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llvm-mirror/include/llvm/Transforms/IPO/Attributor.h
Joseph Huber 4f1fd1c209 [Attributor] Change function internalization to not replace uses in internalized callers 
The current implementation of function internalization creats a copy of each
function and replaces every use. This has the downside that the external
versions of the functions will call into the internalized versions of the
functions. This prevents them from being fully independent of eachother. This
patch replaces the current internalization scheme with a method that creates
all the copies of the functions intended to be internalized first and then
replaces the uses as long as their caller is not already internalized.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106931

(cherry picked from commit adbaa39dfce7a8361d89b6a3b382fd8f50b94727)
2021-08-04 16:35:01 -07:00

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//===- Attributor.h --- Module-wide attribute deduction ---------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Attributor: An inter procedural (abstract) "attribute" deduction framework.
//
// The Attributor framework is an inter procedural abstract analysis (fixpoint
// iteration analysis). The goal is to allow easy deduction of new attributes as
// well as information exchange between abstract attributes in-flight.
//
// The Attributor class is the driver and the link between the various abstract
// attributes. The Attributor will iterate until a fixpoint state is reached by
// all abstract attributes in-flight, or until it will enforce a pessimistic fix
// point because an iteration limit is reached.
//
// Abstract attributes, derived from the AbstractAttribute class, actually
// describe properties of the code. They can correspond to actual LLVM-IR
// attributes, or they can be more general, ultimately unrelated to LLVM-IR
// attributes. The latter is useful when an abstract attributes provides
// information to other abstract attributes in-flight but we might not want to
// manifest the information. The Attributor allows to query in-flight abstract
// attributes through the `Attributor::getAAFor` method (see the method
// description for an example). If the method is used by an abstract attribute
// P, and it results in an abstract attribute Q, the Attributor will
// automatically capture a potential dependence from Q to P. This dependence
// will cause P to be reevaluated whenever Q changes in the future.
//
// The Attributor will only reevaluate abstract attributes that might have
// changed since the last iteration. That means that the Attribute will not
// revisit all instructions/blocks/functions in the module but only query
// an update from a subset of the abstract attributes.
//
// The update method `AbstractAttribute::updateImpl` is implemented by the
// specific "abstract attribute" subclasses. The method is invoked whenever the
// currently assumed state (see the AbstractState class) might not be valid
// anymore. This can, for example, happen if the state was dependent on another
// abstract attribute that changed. In every invocation, the update method has
// to adjust the internal state of an abstract attribute to a point that is
// justifiable by the underlying IR and the current state of abstract attributes
// in-flight. Since the IR is given and assumed to be valid, the information
// derived from it can be assumed to hold. However, information derived from
// other abstract attributes is conditional on various things. If the justifying
// state changed, the `updateImpl` has to revisit the situation and potentially
// find another justification or limit the optimistic assumes made.
//
// Change is the key in this framework. Until a state of no-change, thus a
// fixpoint, is reached, the Attributor will query the abstract attributes
// in-flight to re-evaluate their state. If the (current) state is too
// optimistic, hence it cannot be justified anymore through other abstract
// attributes or the state of the IR, the state of the abstract attribute will
// have to change. Generally, we assume abstract attribute state to be a finite
// height lattice and the update function to be monotone. However, these
// conditions are not enforced because the iteration limit will guarantee
// termination. If an optimistic fixpoint is reached, or a pessimistic fix
// point is enforced after a timeout, the abstract attributes are tasked to
// manifest their result in the IR for passes to come.
//
// Attribute manifestation is not mandatory. If desired, there is support to
// generate a single or multiple LLVM-IR attributes already in the helper struct
// IRAttribute. In the simplest case, a subclass inherits from IRAttribute with
// a proper Attribute::AttrKind as template parameter. The Attributor
// manifestation framework will then create and place a new attribute if it is
// allowed to do so (based on the abstract state). Other use cases can be
// achieved by overloading AbstractAttribute or IRAttribute methods.
//
//
// The "mechanics" of adding a new "abstract attribute":
// - Define a class (transitively) inheriting from AbstractAttribute and one
// (which could be the same) that (transitively) inherits from AbstractState.
// For the latter, consider the already available BooleanState and
// {Inc,Dec,Bit}IntegerState if they fit your needs, e.g., you require only a
// number tracking or bit-encoding.
// - Implement all pure methods. Also use overloading if the attribute is not
// conforming with the "default" behavior: A (set of) LLVM-IR attribute(s) for
// an argument, call site argument, function return value, or function. See
// the class and method descriptions for more information on the two
// "Abstract" classes and their respective methods.
// - Register opportunities for the new abstract attribute in the
// `Attributor::identifyDefaultAbstractAttributes` method if it should be
// counted as a 'default' attribute.
// - Add sufficient tests.
// - Add a Statistics object for bookkeeping. If it is a simple (set of)
// attribute(s) manifested through the Attributor manifestation framework, see
// the bookkeeping function in Attributor.cpp.
// - If instructions with a certain opcode are interesting to the attribute, add
// that opcode to the switch in `Attributor::identifyAbstractAttributes`. This
// will make it possible to query all those instructions through the
// `InformationCache::getOpcodeInstMapForFunction` interface and eliminate the
// need to traverse the IR repeatedly.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_IPO_ATTRIBUTOR_H
#define LLVM_TRANSFORMS_IPO_ATTRIBUTOR_H
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/GraphTraits.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Triple.h"
#include "llvm/ADT/iterator.h"
#include "llvm/Analysis/AssumeBundleQueries.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CGSCCPassManager.h"
#include "llvm/Analysis/LazyCallGraph.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/MustExecute.h"
#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/AbstractCallSite.h"
#include "llvm/IR/ConstantRange.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/TimeProfiler.h"
#include "llvm/Transforms/Utils/CallGraphUpdater.h"
namespace llvm {
struct AADepGraphNode;
struct AADepGraph;
struct Attributor;
struct AbstractAttribute;
struct InformationCache;
struct AAIsDead;
struct AttributorCallGraph;
class AAManager;
class AAResults;
class Function;
/// Abstract Attribute helper functions.
namespace AA {
/// Return true if \p V is dynamically unique, that is, there are no two
/// "instances" of \p V at runtime with different values.
bool isDynamicallyUnique(Attributor &A, const AbstractAttribute &QueryingAA,
const Value &V);
/// Return true if \p V is a valid value in \p Scope, that is a constant or an
/// instruction/argument of \p Scope.
bool isValidInScope(const Value &V, const Function *Scope);
/// Return true if \p V is a valid value at position \p CtxI, that is a
/// constant, an argument of the same function as \p CtxI, or an instruction in
/// that function that dominates \p CtxI.
bool isValidAtPosition(const Value &V, const Instruction &CtxI,
InformationCache &InfoCache);
/// Try to convert \p V to type \p Ty without introducing new instructions. If
/// this is not possible return `nullptr`. Note: this function basically knows
/// how to cast various constants.
Value *getWithType(Value &V, Type &Ty);
/// Return the combination of \p A and \p B such that the result is a possible
/// value of both. \p B is potentially casted to match the type \p Ty or the
/// type of \p A if \p Ty is null.
///
/// Examples:
/// X + none => X
/// not_none + undef => not_none
/// V1 + V2 => nullptr
Optional<Value *>
combineOptionalValuesInAAValueLatice(const Optional<Value *> &A,
const Optional<Value *> &B, Type *Ty);
/// Return the initial value of \p Obj with type \p Ty if that is a constant.
Constant *getInitialValueForObj(Value &Obj, Type &Ty);
/// Collect all potential underlying objects of \p Ptr at position \p CtxI in
/// \p Objects. Assumed information is used and dependences onto \p QueryingAA
/// are added appropriately.
///
/// \returns True if \p Objects contains all assumed underlying objects, and
/// false if something went wrong and the objects could not be
/// determined.
bool getAssumedUnderlyingObjects(Attributor &A, const Value &Ptr,
SmallVectorImpl<Value *> &Objects,
const AbstractAttribute &QueryingAA,
const Instruction *CtxI);
/// Collect all potential values of the one stored by \p SI into
/// \p PotentialCopies. That is, the only copies that were made via the
/// store are assumed to be known and all in \p PotentialCopies. Dependences
/// onto \p QueryingAA are properly tracked, \p UsedAssumedInformation will
/// inform the caller if assumed information was used.
///
/// \returns True if the assumed potential copies are all in \p PotentialCopies,
/// false if something went wrong and the copies could not be
/// determined.
bool getPotentialCopiesOfStoredValue(
Attributor &A, StoreInst &SI, SmallSetVector<Value *, 4> &PotentialCopies,
const AbstractAttribute &QueryingAA, bool &UsedAssumedInformation);
} // namespace AA
/// The value passed to the line option that defines the maximal initialization
/// chain length.
extern unsigned MaxInitializationChainLength;
///{
enum class ChangeStatus {
CHANGED,
UNCHANGED,
};
ChangeStatus operator|(ChangeStatus l, ChangeStatus r);
ChangeStatus &operator|=(ChangeStatus &l, ChangeStatus r);
ChangeStatus operator&(ChangeStatus l, ChangeStatus r);
ChangeStatus &operator&=(ChangeStatus &l, ChangeStatus r);
enum class DepClassTy {
REQUIRED, ///< The target cannot be valid if the source is not.
OPTIONAL, ///< The target may be valid if the source is not.
NONE, ///< Do not track a dependence between source and target.
};
///}
/// The data structure for the nodes of a dependency graph
struct AADepGraphNode {
public:
virtual ~AADepGraphNode(){};
using DepTy = PointerIntPair<AADepGraphNode *, 1>;
protected:
/// Set of dependency graph nodes which should be updated if this one
/// is updated. The bit encodes if it is optional.
TinyPtrVector<DepTy> Deps;
static AADepGraphNode *DepGetVal(DepTy &DT) { return DT.getPointer(); }
static AbstractAttribute *DepGetValAA(DepTy &DT) {
return cast<AbstractAttribute>(DT.getPointer());
}
operator AbstractAttribute *() { return cast<AbstractAttribute>(this); }
public:
using iterator =
mapped_iterator<TinyPtrVector<DepTy>::iterator, decltype(&DepGetVal)>;
using aaiterator =
mapped_iterator<TinyPtrVector<DepTy>::iterator, decltype(&DepGetValAA)>;
aaiterator begin() { return aaiterator(Deps.begin(), &DepGetValAA); }
aaiterator end() { return aaiterator(Deps.end(), &DepGetValAA); }
iterator child_begin() { return iterator(Deps.begin(), &DepGetVal); }
iterator child_end() { return iterator(Deps.end(), &DepGetVal); }
virtual void print(raw_ostream &OS) const { OS << "AADepNode Impl\n"; }
TinyPtrVector<DepTy> &getDeps() { return Deps; }
friend struct Attributor;
friend struct AADepGraph;
};
/// The data structure for the dependency graph
///
/// Note that in this graph if there is an edge from A to B (A -> B),
/// then it means that B depends on A, and when the state of A is
/// updated, node B should also be updated
struct AADepGraph {
AADepGraph() {}
~AADepGraph() {}
using DepTy = AADepGraphNode::DepTy;
static AADepGraphNode *DepGetVal(DepTy &DT) { return DT.getPointer(); }
using iterator =
mapped_iterator<TinyPtrVector<DepTy>::iterator, decltype(&DepGetVal)>;
/// There is no root node for the dependency graph. But the SCCIterator
/// requires a single entry point, so we maintain a fake("synthetic") root
/// node that depends on every node.
AADepGraphNode SyntheticRoot;
AADepGraphNode *GetEntryNode() { return &SyntheticRoot; }
iterator begin() { return SyntheticRoot.child_begin(); }
iterator end() { return SyntheticRoot.child_end(); }
void viewGraph();
/// Dump graph to file
void dumpGraph();
/// Print dependency graph
void print();
};
/// Helper to describe and deal with positions in the LLVM-IR.
///
/// A position in the IR is described by an anchor value and an "offset" that
/// could be the argument number, for call sites and arguments, or an indicator
/// of the "position kind". The kinds, specified in the Kind enum below, include
/// the locations in the attribute list, i.a., function scope and return value,
/// as well as a distinction between call sites and functions. Finally, there
/// are floating values that do not have a corresponding attribute list
/// position.
struct IRPosition {
// NOTE: In the future this definition can be changed to support recursive
// functions.
using CallBaseContext = CallBase;
/// The positions we distinguish in the IR.
enum Kind : char {
IRP_INVALID, ///< An invalid position.
IRP_FLOAT, ///< A position that is not associated with a spot suitable
///< for attributes. This could be any value or instruction.
IRP_RETURNED, ///< An attribute for the function return value.
IRP_CALL_SITE_RETURNED, ///< An attribute for a call site return value.
IRP_FUNCTION, ///< An attribute for a function (scope).
IRP_CALL_SITE, ///< An attribute for a call site (function scope).
IRP_ARGUMENT, ///< An attribute for a function argument.
IRP_CALL_SITE_ARGUMENT, ///< An attribute for a call site argument.
};
/// Default constructor available to create invalid positions implicitly. All
/// other positions need to be created explicitly through the appropriate
/// static member function.
IRPosition() : Enc(nullptr, ENC_VALUE) { verify(); }
/// Create a position describing the value of \p V.
static const IRPosition value(const Value &V,
const CallBaseContext *CBContext = nullptr) {
if (auto *Arg = dyn_cast<Argument>(&V))
return IRPosition::argument(*Arg, CBContext);
if (auto *CB = dyn_cast<CallBase>(&V))
return IRPosition::callsite_returned(*CB);
return IRPosition(const_cast<Value &>(V), IRP_FLOAT, CBContext);
}
/// Create a position describing the function scope of \p F.
/// \p CBContext is used for call base specific analysis.
static const IRPosition function(const Function &F,
const CallBaseContext *CBContext = nullptr) {
return IRPosition(const_cast<Function &>(F), IRP_FUNCTION, CBContext);
}
/// Create a position describing the returned value of \p F.
/// \p CBContext is used for call base specific analysis.
static const IRPosition returned(const Function &F,
const CallBaseContext *CBContext = nullptr) {
return IRPosition(const_cast<Function &>(F), IRP_RETURNED, CBContext);
}
/// Create a position describing the argument \p Arg.
/// \p CBContext is used for call base specific analysis.
static const IRPosition argument(const Argument &Arg,
const CallBaseContext *CBContext = nullptr) {
return IRPosition(const_cast<Argument &>(Arg), IRP_ARGUMENT, CBContext);
}
/// Create a position describing the function scope of \p CB.
static const IRPosition callsite_function(const CallBase &CB) {
return IRPosition(const_cast<CallBase &>(CB), IRP_CALL_SITE);
}
/// Create a position describing the returned value of \p CB.
static const IRPosition callsite_returned(const CallBase &CB) {
return IRPosition(const_cast<CallBase &>(CB), IRP_CALL_SITE_RETURNED);
}
/// Create a position describing the argument of \p CB at position \p ArgNo.
static const IRPosition callsite_argument(const CallBase &CB,
unsigned ArgNo) {
return IRPosition(const_cast<Use &>(CB.getArgOperandUse(ArgNo)),
IRP_CALL_SITE_ARGUMENT);
}
/// Create a position describing the argument of \p ACS at position \p ArgNo.
static const IRPosition callsite_argument(AbstractCallSite ACS,
unsigned ArgNo) {
if (ACS.getNumArgOperands() <= ArgNo)
return IRPosition();
int CSArgNo = ACS.getCallArgOperandNo(ArgNo);
if (CSArgNo >= 0)
return IRPosition::callsite_argument(
cast<CallBase>(*ACS.getInstruction()), CSArgNo);
return IRPosition();
}
/// Create a position with function scope matching the "context" of \p IRP.
/// If \p IRP is a call site (see isAnyCallSitePosition()) then the result
/// will be a call site position, otherwise the function position of the
/// associated function.
static const IRPosition
function_scope(const IRPosition &IRP,
const CallBaseContext *CBContext = nullptr) {
if (IRP.isAnyCallSitePosition()) {
return IRPosition::callsite_function(
cast<CallBase>(IRP.getAnchorValue()));
}
assert(IRP.getAssociatedFunction());
return IRPosition::function(*IRP.getAssociatedFunction(), CBContext);
}
bool operator==(const IRPosition &RHS) const {
return Enc == RHS.Enc && RHS.CBContext == CBContext;
}
bool operator!=(const IRPosition &RHS) const { return !(*this == RHS); }
/// Return the value this abstract attribute is anchored with.
///
/// The anchor value might not be the associated value if the latter is not
/// sufficient to determine where arguments will be manifested. This is, so
/// far, only the case for call site arguments as the value is not sufficient
/// to pinpoint them. Instead, we can use the call site as an anchor.
Value &getAnchorValue() const {
switch (getEncodingBits()) {
case ENC_VALUE:
case ENC_RETURNED_VALUE:
case ENC_FLOATING_FUNCTION:
return *getAsValuePtr();
case ENC_CALL_SITE_ARGUMENT_USE:
return *(getAsUsePtr()->getUser());
default:
llvm_unreachable("Unkown encoding!");
};
}
/// Return the associated function, if any.
Function *getAssociatedFunction() const {
if (auto *CB = dyn_cast<CallBase>(&getAnchorValue())) {
// We reuse the logic that associates callback calles to arguments of a
// call site here to identify the callback callee as the associated
// function.
if (Argument *Arg = getAssociatedArgument())
return Arg->getParent();
return CB->getCalledFunction();
}
return getAnchorScope();
}
/// Return the associated argument, if any.
Argument *getAssociatedArgument() const;
/// Return true if the position refers to a function interface, that is the
/// function scope, the function return, or an argument.
bool isFnInterfaceKind() const {
switch (getPositionKind()) {
case IRPosition::IRP_FUNCTION:
case IRPosition::IRP_RETURNED:
case IRPosition::IRP_ARGUMENT:
return true;
default:
return false;
}
}
/// Return the Function surrounding the anchor value.
Function *getAnchorScope() const {
Value &V = getAnchorValue();
if (isa<Function>(V))
return &cast<Function>(V);
if (isa<Argument>(V))
return cast<Argument>(V).getParent();
if (isa<Instruction>(V))
return cast<Instruction>(V).getFunction();
return nullptr;
}
/// Return the context instruction, if any.
Instruction *getCtxI() const {
Value &V = getAnchorValue();
if (auto *I = dyn_cast<Instruction>(&V))
return I;
if (auto *Arg = dyn_cast<Argument>(&V))
if (!Arg->getParent()->isDeclaration())
return &Arg->getParent()->getEntryBlock().front();
if (auto *F = dyn_cast<Function>(&V))
if (!F->isDeclaration())
return &(F->getEntryBlock().front());
return nullptr;
}
/// Return the value this abstract attribute is associated with.
Value &getAssociatedValue() const {
if (getCallSiteArgNo() < 0 || isa<Argument>(&getAnchorValue()))
return getAnchorValue();
assert(isa<CallBase>(&getAnchorValue()) && "Expected a call base!");
return *cast<CallBase>(&getAnchorValue())
->getArgOperand(getCallSiteArgNo());
}
/// Return the type this abstract attribute is associated with.
Type *getAssociatedType() const {
if (getPositionKind() == IRPosition::IRP_RETURNED)
return getAssociatedFunction()->getReturnType();
return getAssociatedValue().getType();
}
/// Return the callee argument number of the associated value if it is an
/// argument or call site argument, otherwise a negative value. In contrast to
/// `getCallSiteArgNo` this method will always return the "argument number"
/// from the perspective of the callee. This may not the same as the call site
/// if this is a callback call.
int getCalleeArgNo() const {
return getArgNo(/* CallbackCalleeArgIfApplicable */ true);
}
/// Return the call site argument number of the associated value if it is an
/// argument or call site argument, otherwise a negative value. In contrast to
/// `getCalleArgNo` this method will always return the "operand number" from
/// the perspective of the call site. This may not the same as the callee
/// perspective if this is a callback call.
int getCallSiteArgNo() const {
return getArgNo(/* CallbackCalleeArgIfApplicable */ false);
}
/// Return the index in the attribute list for this position.
unsigned getAttrIdx() const {
switch (getPositionKind()) {
case IRPosition::IRP_INVALID:
case IRPosition::IRP_FLOAT:
break;
case IRPosition::IRP_FUNCTION:
case IRPosition::IRP_CALL_SITE:
return AttributeList::FunctionIndex;
case IRPosition::IRP_RETURNED:
case IRPosition::IRP_CALL_SITE_RETURNED:
return AttributeList::ReturnIndex;
case IRPosition::IRP_ARGUMENT:
case IRPosition::IRP_CALL_SITE_ARGUMENT:
return getCallSiteArgNo() + AttributeList::FirstArgIndex;
}
llvm_unreachable(
"There is no attribute index for a floating or invalid position!");
}
/// Return the associated position kind.
Kind getPositionKind() const {
char EncodingBits = getEncodingBits();
if (EncodingBits == ENC_CALL_SITE_ARGUMENT_USE)
return IRP_CALL_SITE_ARGUMENT;
if (EncodingBits == ENC_FLOATING_FUNCTION)
return IRP_FLOAT;
Value *V = getAsValuePtr();
if (!V)
return IRP_INVALID;
if (isa<Argument>(V))
return IRP_ARGUMENT;
if (isa<Function>(V))
return isReturnPosition(EncodingBits) ? IRP_RETURNED : IRP_FUNCTION;
if (isa<CallBase>(V))
return isReturnPosition(EncodingBits) ? IRP_CALL_SITE_RETURNED
: IRP_CALL_SITE;
return IRP_FLOAT;
}
/// TODO: Figure out if the attribute related helper functions should live
/// here or somewhere else.
/// Return true if any kind in \p AKs existing in the IR at a position that
/// will affect this one. See also getAttrs(...).
/// \param IgnoreSubsumingPositions Flag to determine if subsuming positions,
/// e.g., the function position if this is an
/// argument position, should be ignored.
bool hasAttr(ArrayRef<Attribute::AttrKind> AKs,
bool IgnoreSubsumingPositions = false,
Attributor *A = nullptr) const;
/// Return the attributes of any kind in \p AKs existing in the IR at a
/// position that will affect this one. While each position can only have a
/// single attribute of any kind in \p AKs, there are "subsuming" positions
/// that could have an attribute as well. This method returns all attributes
/// found in \p Attrs.
/// \param IgnoreSubsumingPositions Flag to determine if subsuming positions,
/// e.g., the function position if this is an
/// argument position, should be ignored.
void getAttrs(ArrayRef<Attribute::AttrKind> AKs,
SmallVectorImpl<Attribute> &Attrs,
bool IgnoreSubsumingPositions = false,
Attributor *A = nullptr) const;
/// Remove the attribute of kind \p AKs existing in the IR at this position.
void removeAttrs(ArrayRef<Attribute::AttrKind> AKs) const {
if (getPositionKind() == IRP_INVALID || getPositionKind() == IRP_FLOAT)
return;
AttributeList AttrList;
auto *CB = dyn_cast<CallBase>(&getAnchorValue());
if (CB)
AttrList = CB->getAttributes();
else
AttrList = getAssociatedFunction()->getAttributes();
LLVMContext &Ctx = getAnchorValue().getContext();
for (Attribute::AttrKind AK : AKs)
AttrList = AttrList.removeAttribute(Ctx, getAttrIdx(), AK);
if (CB)
CB->setAttributes(AttrList);
else
getAssociatedFunction()->setAttributes(AttrList);
}
bool isAnyCallSitePosition() const {
switch (getPositionKind()) {
case IRPosition::IRP_CALL_SITE:
case IRPosition::IRP_CALL_SITE_RETURNED:
case IRPosition::IRP_CALL_SITE_ARGUMENT:
return true;
default:
return false;
}
}
/// Return true if the position is an argument or call site argument.
bool isArgumentPosition() const {
switch (getPositionKind()) {
case IRPosition::IRP_ARGUMENT:
case IRPosition::IRP_CALL_SITE_ARGUMENT:
return true;
default:
return false;
}
}
/// Return the same position without the call base context.
IRPosition stripCallBaseContext() const {
IRPosition Result = *this;
Result.CBContext = nullptr;
return Result;
}
/// Get the call base context from the position.
const CallBaseContext *getCallBaseContext() const { return CBContext; }
/// Check if the position has any call base context.
bool hasCallBaseContext() const { return CBContext != nullptr; }
/// Special DenseMap key values.
///
///{
static const IRPosition EmptyKey;
static const IRPosition TombstoneKey;
///}
/// Conversion into a void * to allow reuse of pointer hashing.
operator void *() const { return Enc.getOpaqueValue(); }
private:
/// Private constructor for special values only!
explicit IRPosition(void *Ptr, const CallBaseContext *CBContext = nullptr)
: CBContext(CBContext) {
Enc.setFromOpaqueValue(Ptr);
}
/// IRPosition anchored at \p AnchorVal with kind/argument numbet \p PK.
explicit IRPosition(Value &AnchorVal, Kind PK,
const CallBaseContext *CBContext = nullptr)
: CBContext(CBContext) {
switch (PK) {
case IRPosition::IRP_INVALID:
llvm_unreachable("Cannot create invalid IRP with an anchor value!");
break;
case IRPosition::IRP_FLOAT:
// Special case for floating functions.
if (isa<Function>(AnchorVal))
Enc = {&AnchorVal, ENC_FLOATING_FUNCTION};
else
Enc = {&AnchorVal, ENC_VALUE};
break;
case IRPosition::IRP_FUNCTION:
case IRPosition::IRP_CALL_SITE:
Enc = {&AnchorVal, ENC_VALUE};
break;
case IRPosition::IRP_RETURNED:
case IRPosition::IRP_CALL_SITE_RETURNED:
Enc = {&AnchorVal, ENC_RETURNED_VALUE};
break;
case IRPosition::IRP_ARGUMENT:
Enc = {&AnchorVal, ENC_VALUE};
break;
case IRPosition::IRP_CALL_SITE_ARGUMENT:
llvm_unreachable(
"Cannot create call site argument IRP with an anchor value!");
break;
}
verify();
}
/// Return the callee argument number of the associated value if it is an
/// argument or call site argument. See also `getCalleeArgNo` and
/// `getCallSiteArgNo`.
int getArgNo(bool CallbackCalleeArgIfApplicable) const {
if (CallbackCalleeArgIfApplicable)
if (Argument *Arg = getAssociatedArgument())
return Arg->getArgNo();
switch (getPositionKind()) {
case IRPosition::IRP_ARGUMENT:
return cast<Argument>(getAsValuePtr())->getArgNo();
case IRPosition::IRP_CALL_SITE_ARGUMENT: {
Use &U = *getAsUsePtr();
return cast<CallBase>(U.getUser())->getArgOperandNo(&U);
}
default:
return -1;
}
}
/// IRPosition for the use \p U. The position kind \p PK needs to be
/// IRP_CALL_SITE_ARGUMENT, the anchor value is the user, the associated value
/// the used value.
explicit IRPosition(Use &U, Kind PK) {
assert(PK == IRP_CALL_SITE_ARGUMENT &&
"Use constructor is for call site arguments only!");
Enc = {&U, ENC_CALL_SITE_ARGUMENT_USE};
verify();
}
/// Verify internal invariants.
void verify();
/// Return the attributes of kind \p AK existing in the IR as attribute.
bool getAttrsFromIRAttr(Attribute::AttrKind AK,
SmallVectorImpl<Attribute> &Attrs) const;
/// Return the attributes of kind \p AK existing in the IR as operand bundles
/// of an llvm.assume.
bool getAttrsFromAssumes(Attribute::AttrKind AK,
SmallVectorImpl<Attribute> &Attrs,
Attributor &A) const;
/// Return the underlying pointer as Value *, valid for all positions but
/// IRP_CALL_SITE_ARGUMENT.
Value *getAsValuePtr() const {
assert(getEncodingBits() != ENC_CALL_SITE_ARGUMENT_USE &&
"Not a value pointer!");
return reinterpret_cast<Value *>(Enc.getPointer());
}
/// Return the underlying pointer as Use *, valid only for
/// IRP_CALL_SITE_ARGUMENT positions.
Use *getAsUsePtr() const {
assert(getEncodingBits() == ENC_CALL_SITE_ARGUMENT_USE &&
"Not a value pointer!");
return reinterpret_cast<Use *>(Enc.getPointer());
}
/// Return true if \p EncodingBits describe a returned or call site returned
/// position.
static bool isReturnPosition(char EncodingBits) {
return EncodingBits == ENC_RETURNED_VALUE;
}
/// Return true if the encoding bits describe a returned or call site returned
/// position.
bool isReturnPosition() const { return isReturnPosition(getEncodingBits()); }
/// The encoding of the IRPosition is a combination of a pointer and two
/// encoding bits. The values of the encoding bits are defined in the enum
/// below. The pointer is either a Value* (for the first three encoding bit
/// combinations) or Use* (for ENC_CALL_SITE_ARGUMENT_USE).
///
///{
enum {
ENC_VALUE = 0b00,
ENC_RETURNED_VALUE = 0b01,
ENC_FLOATING_FUNCTION = 0b10,
ENC_CALL_SITE_ARGUMENT_USE = 0b11,
};
// Reserve the maximal amount of bits so there is no need to mask out the
// remaining ones. We will not encode anything else in the pointer anyway.
static constexpr int NumEncodingBits =
PointerLikeTypeTraits<void *>::NumLowBitsAvailable;
static_assert(NumEncodingBits >= 2, "At least two bits are required!");
/// The pointer with the encoding bits.
PointerIntPair<void *, NumEncodingBits, char> Enc;
///}
/// Call base context. Used for callsite specific analysis.
const CallBaseContext *CBContext = nullptr;
/// Return the encoding bits.
char getEncodingBits() const { return Enc.getInt(); }
};
/// Helper that allows IRPosition as a key in a DenseMap.
template <> struct DenseMapInfo<IRPosition> {
static inline IRPosition getEmptyKey() { return IRPosition::EmptyKey; }
static inline IRPosition getTombstoneKey() {
return IRPosition::TombstoneKey;
}
static unsigned getHashValue(const IRPosition &IRP) {
return (DenseMapInfo<void *>::getHashValue(IRP) << 4) ^
(DenseMapInfo<Value *>::getHashValue(IRP.getCallBaseContext()));
}
static bool isEqual(const IRPosition &a, const IRPosition &b) {
return a == b;
}
};
/// A visitor class for IR positions.
///
/// Given a position P, the SubsumingPositionIterator allows to visit "subsuming
/// positions" wrt. attributes/information. Thus, if a piece of information
/// holds for a subsuming position, it also holds for the position P.
///
/// The subsuming positions always include the initial position and then,
/// depending on the position kind, additionally the following ones:
/// - for IRP_RETURNED:
/// - the function (IRP_FUNCTION)
/// - for IRP_ARGUMENT:
/// - the function (IRP_FUNCTION)
/// - for IRP_CALL_SITE:
/// - the callee (IRP_FUNCTION), if known
/// - for IRP_CALL_SITE_RETURNED:
/// - the callee (IRP_RETURNED), if known
/// - the call site (IRP_FUNCTION)
/// - the callee (IRP_FUNCTION), if known
/// - for IRP_CALL_SITE_ARGUMENT:
/// - the argument of the callee (IRP_ARGUMENT), if known
/// - the callee (IRP_FUNCTION), if known
/// - the position the call site argument is associated with if it is not
/// anchored to the call site, e.g., if it is an argument then the argument
/// (IRP_ARGUMENT)
class SubsumingPositionIterator {
SmallVector<IRPosition, 4> IRPositions;
using iterator = decltype(IRPositions)::iterator;
public:
SubsumingPositionIterator(const IRPosition &IRP);
iterator begin() { return IRPositions.begin(); }
iterator end() { return IRPositions.end(); }
};
/// Wrapper for FunctoinAnalysisManager.
struct AnalysisGetter {
template <typename Analysis>
typename Analysis::Result *getAnalysis(const Function &F) {
if (!FAM || !F.getParent())
return nullptr;
return &FAM->getResult<Analysis>(const_cast<Function &>(F));
}
AnalysisGetter(FunctionAnalysisManager &FAM) : FAM(&FAM) {}
AnalysisGetter() {}
private:
FunctionAnalysisManager *FAM = nullptr;
};
/// Data structure to hold cached (LLVM-IR) information.
///
/// All attributes are given an InformationCache object at creation time to
/// avoid inspection of the IR by all of them individually. This default
/// InformationCache will hold information required by 'default' attributes,
/// thus the ones deduced when Attributor::identifyDefaultAbstractAttributes(..)
/// is called.
///
/// If custom abstract attributes, registered manually through
/// Attributor::registerAA(...), need more information, especially if it is not
/// reusable, it is advised to inherit from the InformationCache and cast the
/// instance down in the abstract attributes.
struct InformationCache {
InformationCache(const Module &M, AnalysisGetter &AG,
BumpPtrAllocator &Allocator, SetVector<Function *> *CGSCC)
: DL(M.getDataLayout()), Allocator(Allocator),
Explorer(
/* ExploreInterBlock */ true, /* ExploreCFGForward */ true,
/* ExploreCFGBackward */ true,
/* LIGetter */
[&](const Function &F) { return AG.getAnalysis<LoopAnalysis>(F); },
/* DTGetter */
[&](const Function &F) {
return AG.getAnalysis<DominatorTreeAnalysis>(F);
},
/* PDTGetter */
[&](const Function &F) {
return AG.getAnalysis<PostDominatorTreeAnalysis>(F);
}),
AG(AG), CGSCC(CGSCC), TargetTriple(M.getTargetTriple()) {
if (CGSCC)
initializeModuleSlice(*CGSCC);
}
~InformationCache() {
// The FunctionInfo objects are allocated via a BumpPtrAllocator, we call
// the destructor manually.
for (auto &It : FuncInfoMap)
It.getSecond()->~FunctionInfo();
}
/// Apply \p CB to all uses of \p F. If \p LookThroughConstantExprUses is
/// true, constant expression users are not given to \p CB but their uses are
/// traversed transitively.
template <typename CBTy>
static void foreachUse(Function &F, CBTy CB,
bool LookThroughConstantExprUses = true) {
SmallVector<Use *, 8> Worklist(make_pointer_range(F.uses()));
for (unsigned Idx = 0; Idx < Worklist.size(); ++Idx) {
Use &U = *Worklist[Idx];
// Allow use in constant bitcasts and simply look through them.
if (LookThroughConstantExprUses && isa<ConstantExpr>(U.getUser())) {
for (Use &CEU : cast<ConstantExpr>(U.getUser())->uses())
Worklist.push_back(&CEU);
continue;
}
CB(U);
}
}
/// Initialize the ModuleSlice member based on \p SCC. ModuleSlices contains
/// (a subset of) all functions that we can look at during this SCC traversal.
/// This includes functions (transitively) called from the SCC and the
/// (transitive) callers of SCC functions. We also can look at a function if
/// there is a "reference edge", i.a., if the function somehow uses (!=calls)
/// a function in the SCC or a caller of a function in the SCC.
void initializeModuleSlice(SetVector<Function *> &SCC) {
ModuleSlice.insert(SCC.begin(), SCC.end());
SmallPtrSet<Function *, 16> Seen;
SmallVector<Function *, 16> Worklist(SCC.begin(), SCC.end());
while (!Worklist.empty()) {
Function *F = Worklist.pop_back_val();
ModuleSlice.insert(F);
for (Instruction &I : instructions(*F))
if (auto *CB = dyn_cast<CallBase>(&I))
if (Function *Callee = CB->getCalledFunction())
if (Seen.insert(Callee).second)
Worklist.push_back(Callee);
}
Seen.clear();
Worklist.append(SCC.begin(), SCC.end());
while (!Worklist.empty()) {
Function *F = Worklist.pop_back_val();
ModuleSlice.insert(F);
// Traverse all transitive uses.
foreachUse(*F, [&](Use &U) {
if (auto *UsrI = dyn_cast<Instruction>(U.getUser()))
if (Seen.insert(UsrI->getFunction()).second)
Worklist.push_back(UsrI->getFunction());
});
}
}
/// The slice of the module we are allowed to look at.
SmallPtrSet<Function *, 8> ModuleSlice;
/// A vector type to hold instructions.
using InstructionVectorTy = SmallVector<Instruction *, 8>;
/// A map type from opcodes to instructions with this opcode.
using OpcodeInstMapTy = DenseMap<unsigned, InstructionVectorTy *>;
/// Return the map that relates "interesting" opcodes with all instructions
/// with that opcode in \p F.
OpcodeInstMapTy &getOpcodeInstMapForFunction(const Function &F) {
return getFunctionInfo(F).OpcodeInstMap;
}
/// Return the instructions in \p F that may read or write memory.
InstructionVectorTy &getReadOrWriteInstsForFunction(const Function &F) {
return getFunctionInfo(F).RWInsts;
}
/// Return MustBeExecutedContextExplorer
MustBeExecutedContextExplorer &getMustBeExecutedContextExplorer() {
return Explorer;
}
/// Return TargetLibraryInfo for function \p F.
TargetLibraryInfo *getTargetLibraryInfoForFunction(const Function &F) {
return AG.getAnalysis<TargetLibraryAnalysis>(F);
}
/// Return AliasAnalysis Result for function \p F.
AAResults *getAAResultsForFunction(const Function &F);
/// Return true if \p Arg is involved in a must-tail call, thus the argument
/// of the caller or callee.
bool isInvolvedInMustTailCall(const Argument &Arg) {
FunctionInfo &FI = getFunctionInfo(*Arg.getParent());
return FI.CalledViaMustTail || FI.ContainsMustTailCall;
}
/// Return the analysis result from a pass \p AP for function \p F.
template <typename AP>
typename AP::Result *getAnalysisResultForFunction(const Function &F) {
return AG.getAnalysis<AP>(F);
}
/// Return SCC size on call graph for function \p F or 0 if unknown.
unsigned getSccSize(const Function &F) {
if (CGSCC && CGSCC->count(const_cast<Function *>(&F)))
return CGSCC->size();
return 0;
}
/// Return datalayout used in the module.
const DataLayout &getDL() { return DL; }
/// Return the map conaining all the knowledge we have from `llvm.assume`s.
const RetainedKnowledgeMap &getKnowledgeMap() const { return KnowledgeMap; }
/// Return if \p To is potentially reachable form \p From or not
/// If the same query was answered, return cached result
bool getPotentiallyReachable(const Instruction &From, const Instruction &To) {
auto KeyPair = std::make_pair(&From, &To);
auto Iter = PotentiallyReachableMap.find(KeyPair);
if (Iter != PotentiallyReachableMap.end())
return Iter->second;
const Function &F = *From.getFunction();
bool Result = true;
if (From.getFunction() == To.getFunction())
Result = isPotentiallyReachable(&From, &To, nullptr,
AG.getAnalysis<DominatorTreeAnalysis>(F),
AG.getAnalysis<LoopAnalysis>(F));
PotentiallyReachableMap.insert(std::make_pair(KeyPair, Result));
return Result;
}
/// Check whether \p F is part of module slice.
bool isInModuleSlice(const Function &F) {
return ModuleSlice.count(const_cast<Function *>(&F));
}
/// Return true if the stack (llvm::Alloca) can be accessed by other threads.
bool stackIsAccessibleByOtherThreads() { return !targetIsGPU(); }
/// Return true if the target is a GPU.
bool targetIsGPU() {
return TargetTriple.isAMDGPU() || TargetTriple.isNVPTX();
}
private:
struct FunctionInfo {
~FunctionInfo();
/// A nested map that remembers all instructions in a function with a
/// certain instruction opcode (Instruction::getOpcode()).
OpcodeInstMapTy OpcodeInstMap;
/// A map from functions to their instructions that may read or write
/// memory.
InstructionVectorTy RWInsts;
/// Function is called by a `musttail` call.
bool CalledViaMustTail;
/// Function contains a `musttail` call.
bool ContainsMustTailCall;
};
/// A map type from functions to informatio about it.
DenseMap<const Function *, FunctionInfo *> FuncInfoMap;
/// Return information about the function \p F, potentially by creating it.
FunctionInfo &getFunctionInfo(const Function &F) {
FunctionInfo *&FI = FuncInfoMap[&F];
if (!FI) {
FI = new (Allocator) FunctionInfo();
initializeInformationCache(F, *FI);
}
return *FI;
}
/// Initialize the function information cache \p FI for the function \p F.
///
/// This method needs to be called for all function that might be looked at
/// through the information cache interface *prior* to looking at them.
void initializeInformationCache(const Function &F, FunctionInfo &FI);
/// The datalayout used in the module.
const DataLayout &DL;
/// The allocator used to allocate memory, e.g. for `FunctionInfo`s.
BumpPtrAllocator &Allocator;
/// MustBeExecutedContextExplorer
MustBeExecutedContextExplorer Explorer;
/// A map with knowledge retained in `llvm.assume` instructions.
RetainedKnowledgeMap KnowledgeMap;
/// Getters for analysis.
AnalysisGetter &AG;
/// The underlying CGSCC, or null if not available.
SetVector<Function *> *CGSCC;
/// Set of inlineable functions
SmallPtrSet<const Function *, 8> InlineableFunctions;
/// A map for caching results of queries for isPotentiallyReachable
DenseMap<std::pair<const Instruction *, const Instruction *>, bool>
PotentiallyReachableMap;
/// The triple describing the target machine.
Triple TargetTriple;
/// Give the Attributor access to the members so
/// Attributor::identifyDefaultAbstractAttributes(...) can initialize them.
friend struct Attributor;
};
/// The fixpoint analysis framework that orchestrates the attribute deduction.
///
/// The Attributor provides a general abstract analysis framework (guided
/// fixpoint iteration) as well as helper functions for the deduction of
/// (LLVM-IR) attributes. However, also other code properties can be deduced,
/// propagated, and ultimately manifested through the Attributor framework. This
/// is particularly useful if these properties interact with attributes and a
/// co-scheduled deduction allows to improve the solution. Even if not, thus if
/// attributes/properties are completely isolated, they should use the
/// Attributor framework to reduce the number of fixpoint iteration frameworks
/// in the code base. Note that the Attributor design makes sure that isolated
/// attributes are not impacted, in any way, by others derived at the same time
/// if there is no cross-reasoning performed.
///
/// The public facing interface of the Attributor is kept simple and basically
/// allows abstract attributes to one thing, query abstract attributes
/// in-flight. There are two reasons to do this:
/// a) The optimistic state of one abstract attribute can justify an
/// optimistic state of another, allowing to framework to end up with an
/// optimistic (=best possible) fixpoint instead of one based solely on
/// information in the IR.
/// b) This avoids reimplementing various kinds of lookups, e.g., to check
/// for existing IR attributes, in favor of a single lookups interface
/// provided by an abstract attribute subclass.
///
/// NOTE: The mechanics of adding a new "concrete" abstract attribute are
/// described in the file comment.
struct Attributor {
using OptimizationRemarkGetter =
function_ref<OptimizationRemarkEmitter &(Function *)>;
/// Constructor
///
/// \param Functions The set of functions we are deriving attributes for.
/// \param InfoCache Cache to hold various information accessible for
/// the abstract attributes.
/// \param CGUpdater Helper to update an underlying call graph.
/// \param Allowed If not null, a set limiting the attribute opportunities.
/// \param DeleteFns Whether to delete functions.
/// \param RewriteSignatures Whether to rewrite function signatures.
/// \param MaxFixedPointIterations Maximum number of iterations to run until
/// fixpoint.
Attributor(SetVector<Function *> &Functions, InformationCache &InfoCache,
CallGraphUpdater &CGUpdater,
DenseSet<const char *> *Allowed = nullptr, bool DeleteFns = true,
bool RewriteSignatures = true)
: Allocator(InfoCache.Allocator), Functions(Functions),
InfoCache(InfoCache), CGUpdater(CGUpdater), Allowed(Allowed),
DeleteFns(DeleteFns), RewriteSignatures(RewriteSignatures),
MaxFixpointIterations(None), OREGetter(None), PassName("") {}
/// Constructor
///
/// \param Functions The set of functions we are deriving attributes for.
/// \param InfoCache Cache to hold various information accessible for
/// the abstract attributes.
/// \param CGUpdater Helper to update an underlying call graph.
/// \param Allowed If not null, a set limiting the attribute opportunities.
/// \param DeleteFns Whether to delete functions
/// \param MaxFixedPointIterations Maximum number of iterations to run until
/// fixpoint.
/// \param OREGetter A callback function that returns an ORE object from a
/// Function pointer.
/// \param PassName The name of the pass emitting remarks.
Attributor(SetVector<Function *> &Functions, InformationCache &InfoCache,
CallGraphUpdater &CGUpdater, DenseSet<const char *> *Allowed,
bool DeleteFns, bool RewriteSignatures,
Optional<unsigned> MaxFixpointIterations,
OptimizationRemarkGetter OREGetter, const char *PassName)
: Allocator(InfoCache.Allocator), Functions(Functions),
InfoCache(InfoCache), CGUpdater(CGUpdater), Allowed(Allowed),
DeleteFns(DeleteFns), RewriteSignatures(RewriteSignatures),
MaxFixpointIterations(MaxFixpointIterations),
OREGetter(Optional<OptimizationRemarkGetter>(OREGetter)),
PassName(PassName) {}
~Attributor();
/// Run the analyses until a fixpoint is reached or enforced (timeout).
///
/// The attributes registered with this Attributor can be used after as long
/// as the Attributor is not destroyed (it owns the attributes now).
///
/// \Returns CHANGED if the IR was changed, otherwise UNCHANGED.
ChangeStatus run();
/// Lookup an abstract attribute of type \p AAType at position \p IRP. While
/// no abstract attribute is found equivalent positions are checked, see
/// SubsumingPositionIterator. Thus, the returned abstract attribute
/// might be anchored at a different position, e.g., the callee if \p IRP is a
/// call base.
///
/// This method is the only (supported) way an abstract attribute can retrieve
/// information from another abstract attribute. As an example, take an
/// abstract attribute that determines the memory access behavior for a
/// argument (readnone, readonly, ...). It should use `getAAFor` to get the
/// most optimistic information for other abstract attributes in-flight, e.g.
/// the one reasoning about the "captured" state for the argument or the one
/// reasoning on the memory access behavior of the function as a whole.
///
/// If the DepClass enum is set to `DepClassTy::None` the dependence from
/// \p QueryingAA to the return abstract attribute is not automatically
/// recorded. This should only be used if the caller will record the
/// dependence explicitly if necessary, thus if it the returned abstract
/// attribute is used for reasoning. To record the dependences explicitly use
/// the `Attributor::recordDependence` method.
template <typename AAType>
const AAType &getAAFor(const AbstractAttribute &QueryingAA,
const IRPosition &IRP, DepClassTy DepClass) {
return getOrCreateAAFor<AAType>(IRP, &QueryingAA, DepClass,
/* ForceUpdate */ false);
}
/// Similar to getAAFor but the return abstract attribute will be updated (via
/// `AbstractAttribute::update`) even if it is found in the cache. This is
/// especially useful for AAIsDead as changes in liveness can make updates
/// possible/useful that were not happening before as the abstract attribute
/// was assumed dead.
template <typename AAType>
const AAType &getAndUpdateAAFor(const AbstractAttribute &QueryingAA,
const IRPosition &IRP, DepClassTy DepClass) {
return getOrCreateAAFor<AAType>(IRP, &QueryingAA, DepClass,
/* ForceUpdate */ true);
}
/// The version of getAAFor that allows to omit a querying abstract
/// attribute. Using this after Attributor started running is restricted to
/// only the Attributor itself. Initial seeding of AAs can be done via this
/// function.
/// NOTE: ForceUpdate is ignored in any stage other than the update stage.
template <typename AAType>
const AAType &getOrCreateAAFor(IRPosition IRP,
const AbstractAttribute *QueryingAA,
DepClassTy DepClass, bool ForceUpdate = false,
bool UpdateAfterInit = true) {
if (!shouldPropagateCallBaseContext(IRP))
IRP = IRP.stripCallBaseContext();
if (AAType *AAPtr = lookupAAFor<AAType>(IRP, QueryingAA, DepClass,
/* AllowInvalidState */ true)) {
if (ForceUpdate && Phase == AttributorPhase::UPDATE)
updateAA(*AAPtr);
return *AAPtr;
}
// No matching attribute found, create one.
// Use the static create method.
auto &AA = AAType::createForPosition(IRP, *this);
// If we are currenty seeding attributes, enforce seeding rules.
if (Phase == AttributorPhase::SEEDING && !shouldSeedAttribute(AA)) {
AA.getState().indicatePessimisticFixpoint();
return AA;
}
registerAA(AA);
// For now we ignore naked and optnone functions.
bool Invalidate = Allowed && !Allowed->count(&AAType::ID);
const Function *FnScope = IRP.getAnchorScope();
if (FnScope)
Invalidate |= FnScope->hasFnAttribute(Attribute::Naked) ||
FnScope->hasFnAttribute(Attribute::OptimizeNone);
// Avoid too many nested initializations to prevent a stack overflow.
Invalidate |= InitializationChainLength > MaxInitializationChainLength;
// Bootstrap the new attribute with an initial update to propagate
// information, e.g., function -> call site. If it is not on a given
// Allowed we will not perform updates at all.
if (Invalidate) {
AA.getState().indicatePessimisticFixpoint();
return AA;
}
{
TimeTraceScope TimeScope(AA.getName() + "::initialize");
++InitializationChainLength;
AA.initialize(*this);
--InitializationChainLength;
}
// Initialize and update is allowed for code outside of the current function
// set, but only if it is part of module slice we are allowed to look at.
// Only exception is AAIsDeadFunction whose initialization is prevented
// directly, since we don't to compute it twice.
if (FnScope && !Functions.count(const_cast<Function *>(FnScope))) {
if (!getInfoCache().isInModuleSlice(*FnScope)) {
AA.getState().indicatePessimisticFixpoint();
return AA;
}
}
// If this is queried in the manifest stage, we force the AA to indicate
// pessimistic fixpoint immediately.
if (Phase == AttributorPhase::MANIFEST) {
AA.getState().indicatePessimisticFixpoint();
return AA;
}
// Allow seeded attributes to declare dependencies.
// Remember the seeding state.
if (UpdateAfterInit) {
AttributorPhase OldPhase = Phase;
Phase = AttributorPhase::UPDATE;
updateAA(AA);
Phase = OldPhase;
}
if (QueryingAA && AA.getState().isValidState())
recordDependence(AA, const_cast<AbstractAttribute &>(*QueryingAA),
DepClass);
return AA;
}
template <typename AAType>
const AAType &getOrCreateAAFor(const IRPosition &IRP) {
return getOrCreateAAFor<AAType>(IRP, /* QueryingAA */ nullptr,
DepClassTy::NONE);
}
/// Return the attribute of \p AAType for \p IRP if existing and valid. This
/// also allows non-AA users lookup.
template <typename AAType>
AAType *lookupAAFor(const IRPosition &IRP,
const AbstractAttribute *QueryingAA = nullptr,
DepClassTy DepClass = DepClassTy::OPTIONAL,
bool AllowInvalidState = false) {
static_assert(std::is_base_of<AbstractAttribute, AAType>::value,
"Cannot query an attribute with a type not derived from "
"'AbstractAttribute'!");
// Lookup the abstract attribute of type AAType. If found, return it after
// registering a dependence of QueryingAA on the one returned attribute.
AbstractAttribute *AAPtr = AAMap.lookup({&AAType::ID, IRP});
if (!AAPtr)
return nullptr;
AAType *AA = static_cast<AAType *>(AAPtr);
// Do not register a dependence on an attribute with an invalid state.
if (DepClass != DepClassTy::NONE && QueryingAA &&
AA->getState().isValidState())
recordDependence(*AA, const_cast<AbstractAttribute &>(*QueryingAA),
DepClass);
// Return nullptr if this attribute has an invalid state.
if (!AllowInvalidState && !AA->getState().isValidState())
return nullptr;
return AA;
}
/// Explicitly record a dependence from \p FromAA to \p ToAA, that is if
/// \p FromAA changes \p ToAA should be updated as well.
///
/// This method should be used in conjunction with the `getAAFor` method and
/// with the DepClass enum passed to the method set to None. This can
/// be beneficial to avoid false dependences but it requires the users of
/// `getAAFor` to explicitly record true dependences through this method.
/// The \p DepClass flag indicates if the dependence is striclty necessary.
/// That means for required dependences, if \p FromAA changes to an invalid
/// state, \p ToAA can be moved to a pessimistic fixpoint because it required
/// information from \p FromAA but none are available anymore.
void recordDependence(const AbstractAttribute &FromAA,
const AbstractAttribute &ToAA, DepClassTy DepClass);
/// Introduce a new abstract attribute into the fixpoint analysis.
///
/// Note that ownership of the attribute is given to the Attributor. It will
/// invoke delete for the Attributor on destruction of the Attributor.
///
/// Attributes are identified by their IR position (AAType::getIRPosition())
/// and the address of their static member (see AAType::ID).
template <typename AAType> AAType &registerAA(AAType &AA) {
static_assert(std::is_base_of<AbstractAttribute, AAType>::value,
"Cannot register an attribute with a type not derived from "
"'AbstractAttribute'!");
// Put the attribute in the lookup map structure and the container we use to
// keep track of all attributes.
const IRPosition &IRP = AA.getIRPosition();
AbstractAttribute *&AAPtr = AAMap[{&AAType::ID, IRP}];
assert(!AAPtr && "Attribute already in map!");
AAPtr = &AA;
// Register AA with the synthetic root only before the manifest stage.
if (Phase == AttributorPhase::SEEDING || Phase == AttributorPhase::UPDATE)
DG.SyntheticRoot.Deps.push_back(
AADepGraphNode::DepTy(&AA, unsigned(DepClassTy::REQUIRED)));
return AA;
}
/// Return the internal information cache.
InformationCache &getInfoCache() { return InfoCache; }
/// Return true if this is a module pass, false otherwise.
bool isModulePass() const {
return !Functions.empty() &&
Functions.size() == Functions.front()->getParent()->size();
}
/// Return true if we derive attributes for \p Fn
bool isRunOn(Function &Fn) const {
return Functions.empty() || Functions.count(&Fn);
}
/// Determine opportunities to derive 'default' attributes in \p F and create
/// abstract attribute objects for them.
///
/// \param F The function that is checked for attribute opportunities.
///
/// Note that abstract attribute instances are generally created even if the
/// IR already contains the information they would deduce. The most important
/// reason for this is the single interface, the one of the abstract attribute
/// instance, which can be queried without the need to look at the IR in
/// various places.
void identifyDefaultAbstractAttributes(Function &F);
/// Determine whether the function \p F is IPO amendable
///
/// If a function is exactly defined or it has alwaysinline attribute
/// and is viable to be inlined, we say it is IPO amendable
bool isFunctionIPOAmendable(const Function &F) {
return F.hasExactDefinition() || InfoCache.InlineableFunctions.count(&F);
}
/// Mark the internal function \p F as live.
///
/// This will trigger the identification and initialization of attributes for
/// \p F.
void markLiveInternalFunction(const Function &F) {
assert(F.hasLocalLinkage() &&
"Only local linkage is assumed dead initially.");
identifyDefaultAbstractAttributes(const_cast<Function &>(F));
}
/// Helper function to remove callsite.
void removeCallSite(CallInst *CI) {
if (!CI)
return;
CGUpdater.removeCallSite(*CI);
}
/// Record that \p U is to be replaces with \p NV after information was
/// manifested. This also triggers deletion of trivially dead istructions.
bool changeUseAfterManifest(Use &U, Value &NV) {
Value *&V = ToBeChangedUses[&U];
if (V && (V->stripPointerCasts() == NV.stripPointerCasts() ||
isa_and_nonnull<UndefValue>(V)))
return false;
assert((!V || V == &NV || isa<UndefValue>(NV)) &&
"Use was registered twice for replacement with different values!");
V = &NV;
return true;
}
/// Helper function to replace all uses of \p V with \p NV. Return true if
/// there is any change. The flag \p ChangeDroppable indicates if dropppable
/// uses should be changed too.
bool changeValueAfterManifest(Value &V, Value &NV,
bool ChangeDroppable = true) {
auto &Entry = ToBeChangedValues[&V];
Value *&CurNV = Entry.first;
if (CurNV && (CurNV->stripPointerCasts() == NV.stripPointerCasts() ||
isa<UndefValue>(CurNV)))
return false;
assert((!CurNV || CurNV == &NV || isa<UndefValue>(NV)) &&
"Value replacement was registered twice with different values!");
CurNV = &NV;
Entry.second = ChangeDroppable;
return true;
}
/// Record that \p I is to be replaced with `unreachable` after information
/// was manifested.
void changeToUnreachableAfterManifest(Instruction *I) {
ToBeChangedToUnreachableInsts.insert(I);
}
/// Record that \p II has at least one dead successor block. This information
/// is used, e.g., to replace \p II with a call, after information was
/// manifested.
void registerInvokeWithDeadSuccessor(InvokeInst &II) {
InvokeWithDeadSuccessor.push_back(&II);
}
/// Record that \p I is deleted after information was manifested. This also
/// triggers deletion of trivially dead istructions.
void deleteAfterManifest(Instruction &I) { ToBeDeletedInsts.insert(&I); }
/// Record that \p BB is deleted after information was manifested. This also
/// triggers deletion of trivially dead istructions.
void deleteAfterManifest(BasicBlock &BB) { ToBeDeletedBlocks.insert(&BB); }
// Record that \p BB is added during the manifest of an AA. Added basic blocks
// are preserved in the IR.
void registerManifestAddedBasicBlock(BasicBlock &BB) {
ManifestAddedBlocks.insert(&BB);
}
/// Record that \p F is deleted after information was manifested.
void deleteAfterManifest(Function &F) {
if (DeleteFns)
ToBeDeletedFunctions.insert(&F);
}
/// If \p IRP is assumed to be a constant, return it, if it is unclear yet,
/// return None, otherwise return `nullptr`.
Optional<Constant *> getAssumedConstant(const IRPosition &IRP,
const AbstractAttribute &AA,
bool &UsedAssumedInformation);
Optional<Constant *> getAssumedConstant(const Value &V,
const AbstractAttribute &AA,
bool &UsedAssumedInformation) {
return getAssumedConstant(IRPosition::value(V), AA, UsedAssumedInformation);
}
/// If \p V is assumed simplified, return it, if it is unclear yet,
/// return None, otherwise return `nullptr`.
Optional<Value *> getAssumedSimplified(const IRPosition &IRP,
const AbstractAttribute &AA,
bool &UsedAssumedInformation) {
return getAssumedSimplified(IRP, &AA, UsedAssumedInformation);
}
Optional<Value *> getAssumedSimplified(const Value &V,
const AbstractAttribute &AA,
bool &UsedAssumedInformation) {
return getAssumedSimplified(IRPosition::value(V), AA,
UsedAssumedInformation);
}
/// If \p V is assumed simplified, return it, if it is unclear yet,
/// return None, otherwise return `nullptr`. Same as the public version
/// except that it can be used without recording dependences on any \p AA.
Optional<Value *> getAssumedSimplified(const IRPosition &V,
const AbstractAttribute *AA,
bool &UsedAssumedInformation);
/// Register \p CB as a simplification callback.
/// `Attributor::getAssumedSimplified` will use these callbacks before
/// we it will ask `AAValueSimplify`. It is important to ensure this
/// is called before `identifyDefaultAbstractAttributes`, assuming the
/// latter is called at all.
using SimplifictionCallbackTy = std::function<Optional<Value *>(
const IRPosition &, const AbstractAttribute *, bool &)>;
void registerSimplificationCallback(const IRPosition &IRP,
const SimplifictionCallbackTy &CB) {
SimplificationCallbacks[IRP].emplace_back(CB);
}
/// Return true if there is a simplification callback for \p IRP.
bool hasSimplificationCallback(const IRPosition &IRP) {
return SimplificationCallbacks.count(IRP);
}
private:
/// The vector with all simplification callbacks registered by outside AAs.
DenseMap<IRPosition, SmallVector<SimplifictionCallbackTy, 1>>
SimplificationCallbacks;
public:
/// Translate \p V from the callee context into the call site context.
Optional<Value *>
translateArgumentToCallSiteContent(Optional<Value *> V, CallBase &CB,
const AbstractAttribute &AA,
bool &UsedAssumedInformation);
/// Return true if \p AA (or its context instruction) is assumed dead.
///
/// If \p LivenessAA is not provided it is queried.
bool isAssumedDead(const AbstractAttribute &AA, const AAIsDead *LivenessAA,
bool &UsedAssumedInformation,
bool CheckBBLivenessOnly = false,
DepClassTy DepClass = DepClassTy::OPTIONAL);
/// Return true if \p I is assumed dead.
///
/// If \p LivenessAA is not provided it is queried.
bool isAssumedDead(const Instruction &I, const AbstractAttribute *QueryingAA,
const AAIsDead *LivenessAA, bool &UsedAssumedInformation,
bool CheckBBLivenessOnly = false,
DepClassTy DepClass = DepClassTy::OPTIONAL);
/// Return true if \p U is assumed dead.
///
/// If \p FnLivenessAA is not provided it is queried.
bool isAssumedDead(const Use &U, const AbstractAttribute *QueryingAA,
const AAIsDead *FnLivenessAA, bool &UsedAssumedInformation,
bool CheckBBLivenessOnly = false,
DepClassTy DepClass = DepClassTy::OPTIONAL);
/// Return true if \p IRP is assumed dead.
///
/// If \p FnLivenessAA is not provided it is queried.
bool isAssumedDead(const IRPosition &IRP, const AbstractAttribute *QueryingAA,
const AAIsDead *FnLivenessAA, bool &UsedAssumedInformation,
bool CheckBBLivenessOnly = false,
DepClassTy DepClass = DepClassTy::OPTIONAL);
/// Return true if \p BB is assumed dead.
///
/// If \p LivenessAA is not provided it is queried.
bool isAssumedDead(const BasicBlock &BB, const AbstractAttribute *QueryingAA,
const AAIsDead *FnLivenessAA,
DepClassTy DepClass = DepClassTy::OPTIONAL);
/// Check \p Pred on all (transitive) uses of \p V.
///
/// This method will evaluate \p Pred on all (transitive) uses of the
/// associated value and return true if \p Pred holds every time.
bool checkForAllUses(function_ref<bool(const Use &, bool &)> Pred,
const AbstractAttribute &QueryingAA, const Value &V,
bool CheckBBLivenessOnly = false,
DepClassTy LivenessDepClass = DepClassTy::OPTIONAL);
/// Emit a remark generically.
///
/// This template function can be used to generically emit a remark. The
/// RemarkKind should be one of the following:
/// - OptimizationRemark to indicate a successful optimization attempt
/// - OptimizationRemarkMissed to report a failed optimization attempt
/// - OptimizationRemarkAnalysis to provide additional information about an
/// optimization attempt
///
/// The remark is built using a callback function \p RemarkCB that takes a
/// RemarkKind as input and returns a RemarkKind.
template <typename RemarkKind, typename RemarkCallBack>
void emitRemark(Instruction *I, StringRef RemarkName,
RemarkCallBack &&RemarkCB) const {
if (!OREGetter)
return;
Function *F = I->getFunction();
auto &ORE = OREGetter.getValue()(F);
if (RemarkName.startswith("OMP"))
ORE.emit([&]() {
return RemarkCB(RemarkKind(PassName, RemarkName, I))
<< " [" << RemarkName << "]";
});
else
ORE.emit([&]() { return RemarkCB(RemarkKind(PassName, RemarkName, I)); });
}
/// Emit a remark on a function.
template <typename RemarkKind, typename RemarkCallBack>
void emitRemark(Function *F, StringRef RemarkName,
RemarkCallBack &&RemarkCB) const {
if (!OREGetter)
return;
auto &ORE = OREGetter.getValue()(F);
if (RemarkName.startswith("OMP"))
ORE.emit([&]() {
return RemarkCB(RemarkKind(PassName, RemarkName, F))
<< " [" << RemarkName << "]";
});
else
ORE.emit([&]() { return RemarkCB(RemarkKind(PassName, RemarkName, F)); });
}
/// Helper struct used in the communication between an abstract attribute (AA)
/// that wants to change the signature of a function and the Attributor which
/// applies the changes. The struct is partially initialized with the
/// information from the AA (see the constructor). All other members are
/// provided by the Attributor prior to invoking any callbacks.
struct ArgumentReplacementInfo {
/// Callee repair callback type
///
/// The function repair callback is invoked once to rewire the replacement
/// arguments in the body of the new function. The argument replacement info
/// is passed, as build from the registerFunctionSignatureRewrite call, as
/// well as the replacement function and an iteratore to the first
/// replacement argument.
using CalleeRepairCBTy = std::function<void(
const ArgumentReplacementInfo &, Function &, Function::arg_iterator)>;
/// Abstract call site (ACS) repair callback type
///
/// The abstract call site repair callback is invoked once on every abstract
/// call site of the replaced function (\see ReplacedFn). The callback needs
/// to provide the operands for the call to the new replacement function.
/// The number and type of the operands appended to the provided vector
/// (second argument) is defined by the number and types determined through
/// the replacement type vector (\see ReplacementTypes). The first argument
/// is the ArgumentReplacementInfo object registered with the Attributor
/// through the registerFunctionSignatureRewrite call.
using ACSRepairCBTy =
std::function<void(const ArgumentReplacementInfo &, AbstractCallSite,
SmallVectorImpl<Value *> &)>;
/// Simple getters, see the corresponding members for details.
///{
Attributor &getAttributor() const { return A; }
const Function &getReplacedFn() const { return ReplacedFn; }
const Argument &getReplacedArg() const { return ReplacedArg; }
unsigned getNumReplacementArgs() const { return ReplacementTypes.size(); }
const SmallVectorImpl<Type *> &getReplacementTypes() const {
return ReplacementTypes;
}
///}
private:
/// Constructor that takes the argument to be replaced, the types of
/// the replacement arguments, as well as callbacks to repair the call sites
/// and new function after the replacement happened.
ArgumentReplacementInfo(Attributor &A, Argument &Arg,
ArrayRef<Type *> ReplacementTypes,
CalleeRepairCBTy &&CalleeRepairCB,
ACSRepairCBTy &&ACSRepairCB)
: A(A), ReplacedFn(*Arg.getParent()), ReplacedArg(Arg),
ReplacementTypes(ReplacementTypes.begin(), ReplacementTypes.end()),
CalleeRepairCB(std::move(CalleeRepairCB)),
ACSRepairCB(std::move(ACSRepairCB)) {}
/// Reference to the attributor to allow access from the callbacks.
Attributor &A;
/// The "old" function replaced by ReplacementFn.
const Function &ReplacedFn;
/// The "old" argument replaced by new ones defined via ReplacementTypes.
const Argument &ReplacedArg;
/// The types of the arguments replacing ReplacedArg.
const SmallVector<Type *, 8> ReplacementTypes;
/// Callee repair callback, see CalleeRepairCBTy.
const CalleeRepairCBTy CalleeRepairCB;
/// Abstract call site (ACS) repair callback, see ACSRepairCBTy.
const ACSRepairCBTy ACSRepairCB;
/// Allow access to the private members from the Attributor.
friend struct Attributor;
};
/// Check if we can rewrite a function signature.
///
/// The argument \p Arg is replaced with new ones defined by the number,
/// order, and types in \p ReplacementTypes.
///
/// \returns True, if the replacement can be registered, via
/// registerFunctionSignatureRewrite, false otherwise.
bool isValidFunctionSignatureRewrite(Argument &Arg,
ArrayRef<Type *> ReplacementTypes);
/// Register a rewrite for a function signature.
///
/// The argument \p Arg is replaced with new ones defined by the number,
/// order, and types in \p ReplacementTypes. The rewiring at the call sites is
/// done through \p ACSRepairCB and at the callee site through
/// \p CalleeRepairCB.
///
/// \returns True, if the replacement was registered, false otherwise.
bool registerFunctionSignatureRewrite(
Argument &Arg, ArrayRef<Type *> ReplacementTypes,
ArgumentReplacementInfo::CalleeRepairCBTy &&CalleeRepairCB,
ArgumentReplacementInfo::ACSRepairCBTy &&ACSRepairCB);
/// Check \p Pred on all function call sites.
///
/// This method will evaluate \p Pred on call sites and return
/// true if \p Pred holds in every call sites. However, this is only possible
/// all call sites are known, hence the function has internal linkage.
/// If true is returned, \p AllCallSitesKnown is set if all possible call
/// sites of the function have been visited.
bool checkForAllCallSites(function_ref<bool(AbstractCallSite)> Pred,
const AbstractAttribute &QueryingAA,
bool RequireAllCallSites, bool &AllCallSitesKnown);
/// Check \p Pred on all values potentially returned by \p F.
///
/// This method will evaluate \p Pred on all values potentially returned by
/// the function associated with \p QueryingAA. The returned values are
/// matched with their respective return instructions. Returns true if \p Pred
/// holds on all of them.
bool checkForAllReturnedValuesAndReturnInsts(
function_ref<bool(Value &, const SmallSetVector<ReturnInst *, 4> &)> Pred,
const AbstractAttribute &QueryingAA);
/// Check \p Pred on all values potentially returned by the function
/// associated with \p QueryingAA.
///
/// This is the context insensitive version of the method above.
bool checkForAllReturnedValues(function_ref<bool(Value &)> Pred,
const AbstractAttribute &QueryingAA);
/// Check \p Pred on all instructions with an opcode present in \p Opcodes.
///
/// This method will evaluate \p Pred on all instructions with an opcode
/// present in \p Opcode and return true if \p Pred holds on all of them.
bool checkForAllInstructions(function_ref<bool(Instruction &)> Pred,
const AbstractAttribute &QueryingAA,
const ArrayRef<unsigned> &Opcodes,
bool &UsedAssumedInformation,
bool CheckBBLivenessOnly = false,
bool CheckPotentiallyDead = false);
/// Check \p Pred on all call-like instructions (=CallBased derived).
///
/// See checkForAllCallLikeInstructions(...) for more information.
bool checkForAllCallLikeInstructions(function_ref<bool(Instruction &)> Pred,
const AbstractAttribute &QueryingAA,
bool &UsedAssumedInformation,
bool CheckBBLivenessOnly = false,
bool CheckPotentiallyDead = false) {
return checkForAllInstructions(
Pred, QueryingAA,
{(unsigned)Instruction::Invoke, (unsigned)Instruction::CallBr,
(unsigned)Instruction::Call},
UsedAssumedInformation, CheckBBLivenessOnly, CheckPotentiallyDead);
}
/// Check \p Pred on all Read/Write instructions.
///
/// This method will evaluate \p Pred on all instructions that read or write
/// to memory present in the information cache and return true if \p Pred
/// holds on all of them.
bool checkForAllReadWriteInstructions(function_ref<bool(Instruction &)> Pred,
AbstractAttribute &QueryingAA,
bool &UsedAssumedInformation);
/// Create a shallow wrapper for \p F such that \p F has internal linkage
/// afterwards. It also sets the original \p F 's name to anonymous
///
/// A wrapper is a function with the same type (and attributes) as \p F
/// that will only call \p F and return the result, if any.
///
/// Assuming the declaration of looks like:
/// rty F(aty0 arg0, ..., atyN argN);
///
/// The wrapper will then look as follows:
/// rty wrapper(aty0 arg0, ..., atyN argN) {
/// return F(arg0, ..., argN);
/// }
///
static void createShallowWrapper(Function &F);
/// Returns true if the function \p F can be internalized. i.e. it has a
/// compatible linkage.
static bool isInternalizable(Function &F);
/// Make another copy of the function \p F such that the copied version has
/// internal linkage afterwards and can be analysed. Then we replace all uses
/// of the original function to the copied one
///
/// Only non-locally linked functions that have `linkonce_odr` or `weak_odr`
/// linkage can be internalized because these linkages guarantee that other
/// definitions with the same name have the same semantics as this one.
///
/// This will only be run if the `attributor-allow-deep-wrappers` option is
/// set, or if the function is called with \p Force set to true.
///
/// If the function \p F failed to be internalized the return value will be a
/// null pointer.
static Function *internalizeFunction(Function &F, bool Force = false);
/// Make copies of each function in the set \p FnSet such that the copied
/// version has internal linkage afterwards and can be analysed. Then we
/// replace all uses of the original function to the copied one. The map
/// \p FnMap contains a mapping of functions to their internalized versions.
///
/// Only non-locally linked functions that have `linkonce_odr` or `weak_odr`
/// linkage can be internalized because these linkages guarantee that other
/// definitions with the same name have the same semantics as this one.
///
/// This version will internalize all the functions in the set \p FnSet at
/// once and then replace the uses. This prevents internalized functions being
/// called by external functions when there is an internalized version in the
/// module.
static bool internalizeFunctions(SmallPtrSetImpl<Function *> &FnSet,
DenseMap<Function *, Function *> &FnMap);
/// Return the data layout associated with the anchor scope.
const DataLayout &getDataLayout() const { return InfoCache.DL; }
/// The allocator used to allocate memory, e.g. for `AbstractAttribute`s.
BumpPtrAllocator &Allocator;
private:
/// This method will do fixpoint iteration until fixpoint or the
/// maximum iteration count is reached.
///
/// If the maximum iteration count is reached, This method will
/// indicate pessimistic fixpoint on attributes that transitively depend
/// on attributes that were scheduled for an update.
void runTillFixpoint();
/// Gets called after scheduling, manifests attributes to the LLVM IR.
ChangeStatus manifestAttributes();
/// Gets called after attributes have been manifested, cleans up the IR.
/// Deletes dead functions, blocks and instructions.
/// Rewrites function signitures and updates the call graph.
ChangeStatus cleanupIR();
/// Identify internal functions that are effectively dead, thus not reachable
/// from a live entry point. The functions are added to ToBeDeletedFunctions.
void identifyDeadInternalFunctions();
/// Run `::update` on \p AA and track the dependences queried while doing so.
/// Also adjust the state if we know further updates are not necessary.
ChangeStatus updateAA(AbstractAttribute &AA);
/// Remember the dependences on the top of the dependence stack such that they
/// may trigger further updates. (\see DependenceStack)
void rememberDependences();
/// Check \p Pred on all call sites of \p Fn.
///
/// This method will evaluate \p Pred on call sites and return
/// true if \p Pred holds in every call sites. However, this is only possible
/// all call sites are known, hence the function has internal linkage.
/// If true is returned, \p AllCallSitesKnown is set if all possible call
/// sites of the function have been visited.
bool checkForAllCallSites(function_ref<bool(AbstractCallSite)> Pred,
const Function &Fn, bool RequireAllCallSites,
const AbstractAttribute *QueryingAA,
bool &AllCallSitesKnown);
/// Determine if CallBase context in \p IRP should be propagated.
bool shouldPropagateCallBaseContext(const IRPosition &IRP);
/// Apply all requested function signature rewrites
/// (\see registerFunctionSignatureRewrite) and return Changed if the module
/// was altered.
ChangeStatus
rewriteFunctionSignatures(SmallPtrSetImpl<Function *> &ModifiedFns);
/// Check if the Attribute \p AA should be seeded.
/// See getOrCreateAAFor.
bool shouldSeedAttribute(AbstractAttribute &AA);
/// A nested map to lookup abstract attributes based on the argument position
/// on the outer level, and the addresses of the static member (AAType::ID) on
/// the inner level.
///{
using AAMapKeyTy = std::pair<const char *, IRPosition>;
DenseMap<AAMapKeyTy, AbstractAttribute *> AAMap;
///}
/// Map to remember all requested signature changes (= argument replacements).
DenseMap<Function *, SmallVector<std::unique_ptr<ArgumentReplacementInfo>, 8>>
ArgumentReplacementMap;
/// The set of functions we are deriving attributes for.
SetVector<Function *> &Functions;
/// The information cache that holds pre-processed (LLVM-IR) information.
InformationCache &InfoCache;
/// Helper to update an underlying call graph.
CallGraphUpdater &CGUpdater;
/// Abstract Attribute dependency graph
AADepGraph DG;
/// Set of functions for which we modified the content such that it might
/// impact the call graph.
SmallPtrSet<Function *, 8> CGModifiedFunctions;
/// Information about a dependence. If FromAA is changed ToAA needs to be
/// updated as well.
struct DepInfo {
const AbstractAttribute *FromAA;
const AbstractAttribute *ToAA;
DepClassTy DepClass;
};
/// The dependence stack is used to track dependences during an
/// `AbstractAttribute::update` call. As `AbstractAttribute::update` can be
/// recursive we might have multiple vectors of dependences in here. The stack
/// size, should be adjusted according to the expected recursion depth and the
/// inner dependence vector size to the expected number of dependences per
/// abstract attribute. Since the inner vectors are actually allocated on the
/// stack we can be generous with their size.
using DependenceVector = SmallVector<DepInfo, 8>;
SmallVector<DependenceVector *, 16> DependenceStack;
/// If not null, a set limiting the attribute opportunities.
const DenseSet<const char *> *Allowed;
/// Whether to delete functions.
const bool DeleteFns;
/// Whether to rewrite signatures.
const bool RewriteSignatures;
/// Maximum number of fixedpoint iterations.
Optional<unsigned> MaxFixpointIterations;
/// A set to remember the functions we already assume to be live and visited.
DenseSet<const Function *> VisitedFunctions;
/// Uses we replace with a new value after manifest is done. We will remove
/// then trivially dead instructions as well.
DenseMap<Use *, Value *> ToBeChangedUses;
/// Values we replace with a new value after manifest is done. We will remove
/// then trivially dead instructions as well.
DenseMap<Value *, std::pair<Value *, bool>> ToBeChangedValues;
/// Instructions we replace with `unreachable` insts after manifest is done.
SmallDenseSet<WeakVH, 16> ToBeChangedToUnreachableInsts;
/// Invoke instructions with at least a single dead successor block.
SmallVector<WeakVH, 16> InvokeWithDeadSuccessor;
/// A flag that indicates which stage of the process we are in. Initially, the
/// phase is SEEDING. Phase is changed in `Attributor::run()`
enum class AttributorPhase {
SEEDING,
UPDATE,
MANIFEST,
CLEANUP,
} Phase = AttributorPhase::SEEDING;
/// The current initialization chain length. Tracked to avoid stack overflows.
unsigned InitializationChainLength = 0;
/// Functions, blocks, and instructions we delete after manifest is done.
///
///{
SmallPtrSet<Function *, 8> ToBeDeletedFunctions;
SmallPtrSet<BasicBlock *, 8> ToBeDeletedBlocks;
SmallPtrSet<BasicBlock *, 8> ManifestAddedBlocks;
SmallDenseSet<WeakVH, 8> ToBeDeletedInsts;
///}
/// Callback to get an OptimizationRemarkEmitter from a Function *.
Optional<OptimizationRemarkGetter> OREGetter;
/// The name of the pass to emit remarks for.
const char *PassName = "";
friend AADepGraph;
friend AttributorCallGraph;
};
/// An interface to query the internal state of an abstract attribute.
///
/// The abstract state is a minimal interface that allows the Attributor to
/// communicate with the abstract attributes about their internal state without
/// enforcing or exposing implementation details, e.g., the (existence of an)
/// underlying lattice.
///
/// It is sufficient to be able to query if a state is (1) valid or invalid, (2)
/// at a fixpoint, and to indicate to the state that (3) an optimistic fixpoint
/// was reached or (4) a pessimistic fixpoint was enforced.
///
/// All methods need to be implemented by the subclass. For the common use case,
/// a single boolean state or a bit-encoded state, the BooleanState and
/// {Inc,Dec,Bit}IntegerState classes are already provided. An abstract
/// attribute can inherit from them to get the abstract state interface and
/// additional methods to directly modify the state based if needed. See the
/// class comments for help.
struct AbstractState {
virtual ~AbstractState() {}
/// Return if this abstract state is in a valid state. If false, no
/// information provided should be used.
virtual bool isValidState() const = 0;
/// Return if this abstract state is fixed, thus does not need to be updated
/// if information changes as it cannot change itself.
virtual bool isAtFixpoint() const = 0;
/// Indicate that the abstract state should converge to the optimistic state.
///
/// This will usually make the optimistically assumed state the known to be
/// true state.
///
/// \returns ChangeStatus::UNCHANGED as the assumed value should not change.
virtual ChangeStatus indicateOptimisticFixpoint() = 0;
/// Indicate that the abstract state should converge to the pessimistic state.
///
/// This will usually revert the optimistically assumed state to the known to
/// be true state.
///
/// \returns ChangeStatus::CHANGED as the assumed value may change.
virtual ChangeStatus indicatePessimisticFixpoint() = 0;
};
/// Simple state with integers encoding.
///
/// The interface ensures that the assumed bits are always a subset of the known
/// bits. Users can only add known bits and, except through adding known bits,
/// they can only remove assumed bits. This should guarantee monotoniticy and
/// thereby the existence of a fixpoint (if used corretly). The fixpoint is
/// reached when the assumed and known state/bits are equal. Users can
/// force/inidicate a fixpoint. If an optimistic one is indicated, the known
/// state will catch up with the assumed one, for a pessimistic fixpoint it is
/// the other way around.
template <typename base_ty, base_ty BestState, base_ty WorstState>
struct IntegerStateBase : public AbstractState {
using base_t = base_ty;
IntegerStateBase() {}
IntegerStateBase(base_t Assumed) : Assumed(Assumed) {}
/// Return the best possible representable state.
static constexpr base_t getBestState() { return BestState; }
static constexpr base_t getBestState(const IntegerStateBase &) {
return getBestState();
}
/// Return the worst possible representable state.
static constexpr base_t getWorstState() { return WorstState; }
static constexpr base_t getWorstState(const IntegerStateBase &) {
return getWorstState();
}
/// See AbstractState::isValidState()
/// NOTE: For now we simply pretend that the worst possible state is invalid.
bool isValidState() const override { return Assumed != getWorstState(); }
/// See AbstractState::isAtFixpoint()
bool isAtFixpoint() const override { return Assumed == Known; }
/// See AbstractState::indicateOptimisticFixpoint(...)
ChangeStatus indicateOptimisticFixpoint() override {
Known = Assumed;
return ChangeStatus::UNCHANGED;
}
/// See AbstractState::indicatePessimisticFixpoint(...)
ChangeStatus indicatePessimisticFixpoint() override {
Assumed = Known;
return ChangeStatus::CHANGED;
}
/// Return the known state encoding
base_t getKnown() const { return Known; }
/// Return the assumed state encoding.
base_t getAssumed() const { return Assumed; }
/// Equality for IntegerStateBase.
bool
operator==(const IntegerStateBase<base_t, BestState, WorstState> &R) const {
return this->getAssumed() == R.getAssumed() &&
this->getKnown() == R.getKnown();
}
/// Inequality for IntegerStateBase.
bool
operator!=(const IntegerStateBase<base_t, BestState, WorstState> &R) const {
return !(*this == R);
}
/// "Clamp" this state with \p R. The result is subtype dependent but it is
/// intended that only information assumed in both states will be assumed in
/// this one afterwards.
void operator^=(const IntegerStateBase<base_t, BestState, WorstState> &R) {
handleNewAssumedValue(R.getAssumed());
}
/// "Clamp" this state with \p R. The result is subtype dependent but it is
/// intended that information known in either state will be known in
/// this one afterwards.
void operator+=(const IntegerStateBase<base_t, BestState, WorstState> &R) {
handleNewKnownValue(R.getKnown());
}
void operator|=(const IntegerStateBase<base_t, BestState, WorstState> &R) {
joinOR(R.getAssumed(), R.getKnown());
}
void operator&=(const IntegerStateBase<base_t, BestState, WorstState> &R) {
joinAND(R.getAssumed(), R.getKnown());
}
protected:
/// Handle a new assumed value \p Value. Subtype dependent.
virtual void handleNewAssumedValue(base_t Value) = 0;
/// Handle a new known value \p Value. Subtype dependent.
virtual void handleNewKnownValue(base_t Value) = 0;
/// Handle a value \p Value. Subtype dependent.
virtual void joinOR(base_t AssumedValue, base_t KnownValue) = 0;
/// Handle a new assumed value \p Value. Subtype dependent.
virtual void joinAND(base_t AssumedValue, base_t KnownValue) = 0;
/// The known state encoding in an integer of type base_t.
base_t Known = getWorstState();
/// The assumed state encoding in an integer of type base_t.
base_t Assumed = getBestState();
};
/// Specialization of the integer state for a bit-wise encoding.
template <typename base_ty = uint32_t, base_ty BestState = ~base_ty(0),
base_ty WorstState = 0>
struct BitIntegerState
: public IntegerStateBase<base_ty, BestState, WorstState> {
using base_t = base_ty;
/// Return true if the bits set in \p BitsEncoding are "known bits".
bool isKnown(base_t BitsEncoding) const {
return (this->Known & BitsEncoding) == BitsEncoding;
}
/// Return true if the bits set in \p BitsEncoding are "assumed bits".
bool isAssumed(base_t BitsEncoding) const {
return (this->Assumed & BitsEncoding) == BitsEncoding;
}
/// Add the bits in \p BitsEncoding to the "known bits".
BitIntegerState &addKnownBits(base_t Bits) {
// Make sure we never miss any "known bits".
this->Assumed |= Bits;
this->Known |= Bits;
return *this;
}
/// Remove the bits in \p BitsEncoding from the "assumed bits" if not known.
BitIntegerState &removeAssumedBits(base_t BitsEncoding) {
return intersectAssumedBits(~BitsEncoding);
}
/// Remove the bits in \p BitsEncoding from the "known bits".
BitIntegerState &removeKnownBits(base_t BitsEncoding) {
this->Known = (this->Known & ~BitsEncoding);
return *this;
}
/// Keep only "assumed bits" also set in \p BitsEncoding but all known ones.
BitIntegerState &intersectAssumedBits(base_t BitsEncoding) {
// Make sure we never loose any "known bits".
this->Assumed = (this->Assumed & BitsEncoding) | this->Known;
return *this;
}
private:
void handleNewAssumedValue(base_t Value) override {
intersectAssumedBits(Value);
}
void handleNewKnownValue(base_t Value) override { addKnownBits(Value); }
void joinOR(base_t AssumedValue, base_t KnownValue) override {
this->Known |= KnownValue;
this->Assumed |= AssumedValue;
}
void joinAND(base_t AssumedValue, base_t KnownValue) override {
this->Known &= KnownValue;
this->Assumed &= AssumedValue;
}
};
/// Specialization of the integer state for an increasing value, hence ~0u is
/// the best state and 0 the worst.
template <typename base_ty = uint32_t, base_ty BestState = ~base_ty(0),
base_ty WorstState = 0>
struct IncIntegerState
: public IntegerStateBase<base_ty, BestState, WorstState> {
using super = IntegerStateBase<base_ty, BestState, WorstState>;
using base_t = base_ty;
IncIntegerState() : super() {}
IncIntegerState(base_t Assumed) : super(Assumed) {}
/// Return the best possible representable state.
static constexpr base_t getBestState() { return BestState; }
static constexpr base_t
getBestState(const IncIntegerState<base_ty, BestState, WorstState> &) {
return getBestState();
}
/// Take minimum of assumed and \p Value.
IncIntegerState &takeAssumedMinimum(base_t Value) {
// Make sure we never loose "known value".
this->Assumed = std::max(std::min(this->Assumed, Value), this->Known);
return *this;
}
/// Take maximum of known and \p Value.
IncIntegerState &takeKnownMaximum(base_t Value) {
// Make sure we never loose "known value".
this->Assumed = std::max(Value, this->Assumed);
this->Known = std::max(Value, this->Known);
return *this;
}
private:
void handleNewAssumedValue(base_t Value) override {
takeAssumedMinimum(Value);
}
void handleNewKnownValue(base_t Value) override { takeKnownMaximum(Value); }
void joinOR(base_t AssumedValue, base_t KnownValue) override {
this->Known = std::max(this->Known, KnownValue);
this->Assumed = std::max(this->Assumed, AssumedValue);
}
void joinAND(base_t AssumedValue, base_t KnownValue) override {
this->Known = std::min(this->Known, KnownValue);
this->Assumed = std::min(this->Assumed, AssumedValue);
}
};
/// Specialization of the integer state for a decreasing value, hence 0 is the
/// best state and ~0u the worst.
template <typename base_ty = uint32_t>
struct DecIntegerState : public IntegerStateBase<base_ty, 0, ~base_ty(0)> {
using base_t = base_ty;
/// Take maximum of assumed and \p Value.
DecIntegerState &takeAssumedMaximum(base_t Value) {
// Make sure we never loose "known value".
this->Assumed = std::min(std::max(this->Assumed, Value), this->Known);
return *this;
}
/// Take minimum of known and \p Value.
DecIntegerState &takeKnownMinimum(base_t Value) {
// Make sure we never loose "known value".
this->Assumed = std::min(Value, this->Assumed);
this->Known = std::min(Value, this->Known);
return *this;
}
private:
void handleNewAssumedValue(base_t Value) override {
takeAssumedMaximum(Value);
}
void handleNewKnownValue(base_t Value) override { takeKnownMinimum(Value); }
void joinOR(base_t AssumedValue, base_t KnownValue) override {
this->Assumed = std::min(this->Assumed, KnownValue);
this->Assumed = std::min(this->Assumed, AssumedValue);
}
void joinAND(base_t AssumedValue, base_t KnownValue) override {
this->Assumed = std::max(this->Assumed, KnownValue);
this->Assumed = std::max(this->Assumed, AssumedValue);
}
};
/// Simple wrapper for a single bit (boolean) state.
struct BooleanState : public IntegerStateBase<bool, 1, 0> {
using super = IntegerStateBase<bool, 1, 0>;
using base_t = IntegerStateBase::base_t;
BooleanState() : super() {}
BooleanState(base_t Assumed) : super(Assumed) {}
/// Set the assumed value to \p Value but never below the known one.
void setAssumed(bool Value) { Assumed &= (Known | Value); }
/// Set the known and asssumed value to \p Value.
void setKnown(bool Value) {
Known |= Value;
Assumed |= Value;
}
/// Return true if the state is assumed to hold.
bool isAssumed() const { return getAssumed(); }
/// Return true if the state is known to hold.
bool isKnown() const { return getKnown(); }
private:
void handleNewAssumedValue(base_t Value) override {
if (!Value)
Assumed = Known;
}
void handleNewKnownValue(base_t Value) override {
if (Value)
Known = (Assumed = Value);
}
void joinOR(base_t AssumedValue, base_t KnownValue) override {
Known |= KnownValue;
Assumed |= AssumedValue;
}
void joinAND(base_t AssumedValue, base_t KnownValue) override {
Known &= KnownValue;
Assumed &= AssumedValue;
}
};
/// State for an integer range.
struct IntegerRangeState : public AbstractState {
/// Bitwidth of the associated value.
uint32_t BitWidth;
/// State representing assumed range, initially set to empty.
ConstantRange Assumed;
/// State representing known range, initially set to [-inf, inf].
ConstantRange Known;
IntegerRangeState(uint32_t BitWidth)
: BitWidth(BitWidth), Assumed(ConstantRange::getEmpty(BitWidth)),
Known(ConstantRange::getFull(BitWidth)) {}
IntegerRangeState(const ConstantRange &CR)
: BitWidth(CR.getBitWidth()), Assumed(CR),
Known(getWorstState(CR.getBitWidth())) {}
/// Return the worst possible representable state.
static ConstantRange getWorstState(uint32_t BitWidth) {
return ConstantRange::getFull(BitWidth);
}
/// Return the best possible representable state.
static ConstantRange getBestState(uint32_t BitWidth) {
return ConstantRange::getEmpty(BitWidth);
}
static ConstantRange getBestState(const IntegerRangeState &IRS) {
return getBestState(IRS.getBitWidth());
}
/// Return associated values' bit width.
uint32_t getBitWidth() const { return BitWidth; }
/// See AbstractState::isValidState()
bool isValidState() const override {
return BitWidth > 0 && !Assumed.isFullSet();
}
/// See AbstractState::isAtFixpoint()
bool isAtFixpoint() const override { return Assumed == Known; }
/// See AbstractState::indicateOptimisticFixpoint(...)
ChangeStatus indicateOptimisticFixpoint() override {
Known = Assumed;
return ChangeStatus::CHANGED;
}
/// See AbstractState::indicatePessimisticFixpoint(...)
ChangeStatus indicatePessimisticFixpoint() override {
Assumed = Known;
return ChangeStatus::CHANGED;
}
/// Return the known state encoding
ConstantRange getKnown() const { return Known; }
/// Return the assumed state encoding.
ConstantRange getAssumed() const { return Assumed; }
/// Unite assumed range with the passed state.
void unionAssumed(const ConstantRange &R) {
// Don't loose a known range.
Assumed = Assumed.unionWith(R).intersectWith(Known);
}
/// See IntegerRangeState::unionAssumed(..).
void unionAssumed(const IntegerRangeState &R) {
unionAssumed(R.getAssumed());
}
/// Unite known range with the passed state.
void unionKnown(const ConstantRange &R) {
// Don't loose a known range.
Known = Known.unionWith(R);
Assumed = Assumed.unionWith(Known);
}
/// See IntegerRangeState::unionKnown(..).
void unionKnown(const IntegerRangeState &R) { unionKnown(R.getKnown()); }
/// Intersect known range with the passed state.
void intersectKnown(const ConstantRange &R) {
Assumed = Assumed.intersectWith(R);
Known = Known.intersectWith(R);
}
/// See IntegerRangeState::intersectKnown(..).
void intersectKnown(const IntegerRangeState &R) {
intersectKnown(R.getKnown());
}
/// Equality for IntegerRangeState.
bool operator==(const IntegerRangeState &R) const {
return getAssumed() == R.getAssumed() && getKnown() == R.getKnown();
}
/// "Clamp" this state with \p R. The result is subtype dependent but it is
/// intended that only information assumed in both states will be assumed in
/// this one afterwards.
IntegerRangeState operator^=(const IntegerRangeState &R) {
// NOTE: `^=` operator seems like `intersect` but in this case, we need to
// take `union`.
unionAssumed(R);
return *this;
}
IntegerRangeState operator&=(const IntegerRangeState &R) {
// NOTE: `&=` operator seems like `intersect` but in this case, we need to
// take `union`.
unionKnown(R);
unionAssumed(R);
return *this;
}
};
/// Helper struct necessary as the modular build fails if the virtual method
/// IRAttribute::manifest is defined in the Attributor.cpp.
struct IRAttributeManifest {
static ChangeStatus manifestAttrs(Attributor &A, const IRPosition &IRP,
const ArrayRef<Attribute> &DeducedAttrs,
bool ForceReplace = false);
};
/// Helper to tie a abstract state implementation to an abstract attribute.
template <typename StateTy, typename BaseType, class... Ts>
struct StateWrapper : public BaseType, public StateTy {
/// Provide static access to the type of the state.
using StateType = StateTy;
StateWrapper(const IRPosition &IRP, Ts... Args)
: BaseType(IRP), StateTy(Args...) {}
/// See AbstractAttribute::getState(...).
StateType &getState() override { return *this; }
/// See AbstractAttribute::getState(...).
const StateType &getState() const override { return *this; }
};
/// Helper class that provides common functionality to manifest IR attributes.
template <Attribute::AttrKind AK, typename BaseType>
struct IRAttribute : public BaseType {
IRAttribute(const IRPosition &IRP) : BaseType(IRP) {}
/// See AbstractAttribute::initialize(...).
virtual void initialize(Attributor &A) override {
const IRPosition &IRP = this->getIRPosition();
if (isa<UndefValue>(IRP.getAssociatedValue()) ||
this->hasAttr(getAttrKind(), /* IgnoreSubsumingPositions */ false,
&A)) {
this->getState().indicateOptimisticFixpoint();
return;
}
bool IsFnInterface = IRP.isFnInterfaceKind();
const Function *FnScope = IRP.getAnchorScope();
// TODO: Not all attributes require an exact definition. Find a way to
// enable deduction for some but not all attributes in case the
// definition might be changed at runtime, see also
// http://lists.llvm.org/pipermail/llvm-dev/2018-February/121275.html.
// TODO: We could always determine abstract attributes and if sufficient
// information was found we could duplicate the functions that do not
// have an exact definition.
if (IsFnInterface && (!FnScope || !A.isFunctionIPOAmendable(*FnScope)))
this->getState().indicatePessimisticFixpoint();
}
/// See AbstractAttribute::manifest(...).
ChangeStatus manifest(Attributor &A) override {
if (isa<UndefValue>(this->getIRPosition().getAssociatedValue()))
return ChangeStatus::UNCHANGED;
SmallVector<Attribute, 4> DeducedAttrs;
getDeducedAttributes(this->getAnchorValue().getContext(), DeducedAttrs);
return IRAttributeManifest::manifestAttrs(A, this->getIRPosition(),
DeducedAttrs);
}
/// Return the kind that identifies the abstract attribute implementation.
Attribute::AttrKind getAttrKind() const { return AK; }
/// Return the deduced attributes in \p Attrs.
virtual void getDeducedAttributes(LLVMContext &Ctx,
SmallVectorImpl<Attribute> &Attrs) const {
Attrs.emplace_back(Attribute::get(Ctx, getAttrKind()));
}
};
/// Base struct for all "concrete attribute" deductions.
///
/// The abstract attribute is a minimal interface that allows the Attributor to
/// orchestrate the abstract/fixpoint analysis. The design allows to hide away
/// implementation choices made for the subclasses but also to structure their
/// implementation and simplify the use of other abstract attributes in-flight.
///
/// To allow easy creation of new attributes, most methods have default
/// implementations. The ones that do not are generally straight forward, except
/// `AbstractAttribute::updateImpl` which is the location of most reasoning
/// associated with the abstract attribute. The update is invoked by the
/// Attributor in case the situation used to justify the current optimistic
/// state might have changed. The Attributor determines this automatically
/// by monitoring the `Attributor::getAAFor` calls made by abstract attributes.
///
/// The `updateImpl` method should inspect the IR and other abstract attributes
/// in-flight to justify the best possible (=optimistic) state. The actual
/// implementation is, similar to the underlying abstract state encoding, not
/// exposed. In the most common case, the `updateImpl` will go through a list of
/// reasons why its optimistic state is valid given the current information. If
/// any combination of them holds and is sufficient to justify the current
/// optimistic state, the method shall return UNCHAGED. If not, the optimistic
/// state is adjusted to the situation and the method shall return CHANGED.
///
/// If the manifestation of the "concrete attribute" deduced by the subclass
/// differs from the "default" behavior, which is a (set of) LLVM-IR
/// attribute(s) for an argument, call site argument, function return value, or
/// function, the `AbstractAttribute::manifest` method should be overloaded.
///
/// NOTE: If the state obtained via getState() is INVALID, thus if
/// AbstractAttribute::getState().isValidState() returns false, no
/// information provided by the methods of this class should be used.
/// NOTE: The Attributor currently has certain limitations to what we can do.
/// As a general rule of thumb, "concrete" abstract attributes should *for
/// now* only perform "backward" information propagation. That means
/// optimistic information obtained through abstract attributes should
/// only be used at positions that precede the origin of the information
/// with regards to the program flow. More practically, information can
/// *now* be propagated from instructions to their enclosing function, but
/// *not* from call sites to the called function. The mechanisms to allow
/// both directions will be added in the future.
/// NOTE: The mechanics of adding a new "concrete" abstract attribute are
/// described in the file comment.
struct AbstractAttribute : public IRPosition, public AADepGraphNode {
using StateType = AbstractState;
AbstractAttribute(const IRPosition &IRP) : IRPosition(IRP) {}
/// Virtual destructor.
virtual ~AbstractAttribute() {}
/// This function is used to identify if an \p DGN is of type
/// AbstractAttribute so that the dyn_cast and cast can use such information
/// to cast an AADepGraphNode to an AbstractAttribute.
///
/// We eagerly return true here because all AADepGraphNodes except for the
/// Synthethis Node are of type AbstractAttribute
static bool classof(const AADepGraphNode *DGN) { return true; }
/// Initialize the state with the information in the Attributor \p A.
///
/// This function is called by the Attributor once all abstract attributes
/// have been identified. It can and shall be used for task like:
/// - identify existing knowledge in the IR and use it for the "known state"
/// - perform any work that is not going to change over time, e.g., determine
/// a subset of the IR, or attributes in-flight, that have to be looked at
/// in the `updateImpl` method.
virtual void initialize(Attributor &A) {}
/// Return the internal abstract state for inspection.
virtual StateType &getState() = 0;
virtual const StateType &getState() const = 0;
/// Return an IR position, see struct IRPosition.
const IRPosition &getIRPosition() const { return *this; };
IRPosition &getIRPosition() { return *this; };
/// Helper functions, for debug purposes only.
///{
void print(raw_ostream &OS) const override;
virtual void printWithDeps(raw_ostream &OS) const;
void dump() const { print(dbgs()); }
/// This function should return the "summarized" assumed state as string.
virtual const std::string getAsStr() const = 0;
/// This function should return the name of the AbstractAttribute
virtual const std::string getName() const = 0;
/// This function should return the address of the ID of the AbstractAttribute
virtual const char *getIdAddr() const = 0;
///}
/// Allow the Attributor access to the protected methods.
friend struct Attributor;
protected:
/// Hook for the Attributor to trigger an update of the internal state.
///
/// If this attribute is already fixed, this method will return UNCHANGED,
/// otherwise it delegates to `AbstractAttribute::updateImpl`.
///
/// \Return CHANGED if the internal state changed, otherwise UNCHANGED.
ChangeStatus update(Attributor &A);
/// Hook for the Attributor to trigger the manifestation of the information
/// represented by the abstract attribute in the LLVM-IR.
///
/// \Return CHANGED if the IR was altered, otherwise UNCHANGED.
virtual ChangeStatus manifest(Attributor &A) {
return ChangeStatus::UNCHANGED;
}
/// Hook to enable custom statistic tracking, called after manifest that
/// resulted in a change if statistics are enabled.
///
/// We require subclasses to provide an implementation so we remember to
/// add statistics for them.
virtual void trackStatistics() const = 0;
/// The actual update/transfer function which has to be implemented by the
/// derived classes.
///
/// If it is called, the environment has changed and we have to determine if
/// the current information is still valid or adjust it otherwise.
///
/// \Return CHANGED if the internal state changed, otherwise UNCHANGED.
virtual ChangeStatus updateImpl(Attributor &A) = 0;
};
/// Forward declarations of output streams for debug purposes.
///
///{
raw_ostream &operator<<(raw_ostream &OS, const AbstractAttribute &AA);
raw_ostream &operator<<(raw_ostream &OS, ChangeStatus S);
raw_ostream &operator<<(raw_ostream &OS, IRPosition::Kind);
raw_ostream &operator<<(raw_ostream &OS, const IRPosition &);
raw_ostream &operator<<(raw_ostream &OS, const AbstractState &State);
template <typename base_ty, base_ty BestState, base_ty WorstState>
raw_ostream &
operator<<(raw_ostream &OS,
const IntegerStateBase<base_ty, BestState, WorstState> &S) {
return OS << "(" << S.getKnown() << "-" << S.getAssumed() << ")"
<< static_cast<const AbstractState &>(S);
}
raw_ostream &operator<<(raw_ostream &OS, const IntegerRangeState &State);
///}
struct AttributorPass : public PassInfoMixin<AttributorPass> {
PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
};
struct AttributorCGSCCPass : public PassInfoMixin<AttributorCGSCCPass> {
PreservedAnalyses run(LazyCallGraph::SCC &C, CGSCCAnalysisManager &AM,
LazyCallGraph &CG, CGSCCUpdateResult &UR);
};
Pass *createAttributorLegacyPass();
Pass *createAttributorCGSCCLegacyPass();
/// Helper function to clamp a state \p S of type \p StateType with the
/// information in \p R and indicate/return if \p S did change (as-in update is
/// required to be run again).
template <typename StateType>
ChangeStatus clampStateAndIndicateChange(StateType &S, const StateType &R) {
auto Assumed = S.getAssumed();
S ^= R;
return Assumed == S.getAssumed() ? ChangeStatus::UNCHANGED
: ChangeStatus::CHANGED;
}
/// ----------------------------------------------------------------------------
/// Abstract Attribute Classes
/// ----------------------------------------------------------------------------
/// An abstract attribute for the returned values of a function.
struct AAReturnedValues
: public IRAttribute<Attribute::Returned, AbstractAttribute> {
AAReturnedValues(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return an assumed unique return value if a single candidate is found. If
/// there cannot be one, return a nullptr. If it is not clear yet, return the
/// Optional::NoneType.
Optional<Value *> getAssumedUniqueReturnValue(Attributor &A) const;
/// Check \p Pred on all returned values.
///
/// This method will evaluate \p Pred on returned values and return
/// true if (1) all returned values are known, and (2) \p Pred returned true
/// for all returned values.
///
/// Note: Unlike the Attributor::checkForAllReturnedValuesAndReturnInsts
/// method, this one will not filter dead return instructions.
virtual bool checkForAllReturnedValuesAndReturnInsts(
function_ref<bool(Value &, const SmallSetVector<ReturnInst *, 4> &)> Pred)
const = 0;
using iterator =
MapVector<Value *, SmallSetVector<ReturnInst *, 4>>::iterator;
using const_iterator =
MapVector<Value *, SmallSetVector<ReturnInst *, 4>>::const_iterator;
virtual llvm::iterator_range<iterator> returned_values() = 0;
virtual llvm::iterator_range<const_iterator> returned_values() const = 0;
virtual size_t getNumReturnValues() const = 0;
/// Create an abstract attribute view for the position \p IRP.
static AAReturnedValues &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAReturnedValues"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAReturnedValues
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
struct AANoUnwind
: public IRAttribute<Attribute::NoUnwind,
StateWrapper<BooleanState, AbstractAttribute>> {
AANoUnwind(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Returns true if nounwind is assumed.
bool isAssumedNoUnwind() const { return getAssumed(); }
/// Returns true if nounwind is known.
bool isKnownNoUnwind() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANoUnwind &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoUnwind"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoUnwind
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
struct AANoSync
: public IRAttribute<Attribute::NoSync,
StateWrapper<BooleanState, AbstractAttribute>> {
AANoSync(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Returns true if "nosync" is assumed.
bool isAssumedNoSync() const { return getAssumed(); }
/// Returns true if "nosync" is known.
bool isKnownNoSync() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANoSync &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoSync"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoSync
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for all nonnull attributes.
struct AANonNull
: public IRAttribute<Attribute::NonNull,
StateWrapper<BooleanState, AbstractAttribute>> {
AANonNull(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if we assume that the underlying value is nonnull.
bool isAssumedNonNull() const { return getAssumed(); }
/// Return true if we know that underlying value is nonnull.
bool isKnownNonNull() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANonNull &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANonNull"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANonNull
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract attribute for norecurse.
struct AANoRecurse
: public IRAttribute<Attribute::NoRecurse,
StateWrapper<BooleanState, AbstractAttribute>> {
AANoRecurse(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if "norecurse" is assumed.
bool isAssumedNoRecurse() const { return getAssumed(); }
/// Return true if "norecurse" is known.
bool isKnownNoRecurse() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANoRecurse &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoRecurse"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoRecurse
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract attribute for willreturn.
struct AAWillReturn
: public IRAttribute<Attribute::WillReturn,
StateWrapper<BooleanState, AbstractAttribute>> {
AAWillReturn(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if "willreturn" is assumed.
bool isAssumedWillReturn() const { return getAssumed(); }
/// Return true if "willreturn" is known.
bool isKnownWillReturn() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AAWillReturn &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAWillReturn"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AAWillReturn
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract attribute for undefined behavior.
struct AAUndefinedBehavior
: public StateWrapper<BooleanState, AbstractAttribute> {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AAUndefinedBehavior(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// Return true if "undefined behavior" is assumed.
bool isAssumedToCauseUB() const { return getAssumed(); }
/// Return true if "undefined behavior" is assumed for a specific instruction.
virtual bool isAssumedToCauseUB(Instruction *I) const = 0;
/// Return true if "undefined behavior" is known.
bool isKnownToCauseUB() const { return getKnown(); }
/// Return true if "undefined behavior" is known for a specific instruction.
virtual bool isKnownToCauseUB(Instruction *I) const = 0;
/// Create an abstract attribute view for the position \p IRP.
static AAUndefinedBehavior &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAUndefinedBehavior"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAUndefineBehavior
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface to determine reachability of point A to B.
struct AAReachability : public StateWrapper<BooleanState, AbstractAttribute> {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AAReachability(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// Returns true if 'From' instruction is assumed to reach, 'To' instruction.
/// Users should provide two positions they are interested in, and the class
/// determines (and caches) reachability.
bool isAssumedReachable(Attributor &A, const Instruction &From,
const Instruction &To) const {
if (!getState().isValidState())
return true;
return A.getInfoCache().getPotentiallyReachable(From, To);
}
/// Returns true if 'From' instruction is known to reach, 'To' instruction.
/// Users should provide two positions they are interested in, and the class
/// determines (and caches) reachability.
bool isKnownReachable(Attributor &A, const Instruction &From,
const Instruction &To) const {
if (!getState().isValidState())
return false;
return A.getInfoCache().getPotentiallyReachable(From, To);
}
/// Create an abstract attribute view for the position \p IRP.
static AAReachability &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAReachability"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAReachability
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for all noalias attributes.
struct AANoAlias
: public IRAttribute<Attribute::NoAlias,
StateWrapper<BooleanState, AbstractAttribute>> {
AANoAlias(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if we assume that the underlying value is alias.
bool isAssumedNoAlias() const { return getAssumed(); }
/// Return true if we know that underlying value is noalias.
bool isKnownNoAlias() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANoAlias &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoAlias"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoAlias
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An AbstractAttribute for nofree.
struct AANoFree
: public IRAttribute<Attribute::NoFree,
StateWrapper<BooleanState, AbstractAttribute>> {
AANoFree(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if "nofree" is assumed.
bool isAssumedNoFree() const { return getAssumed(); }
/// Return true if "nofree" is known.
bool isKnownNoFree() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANoFree &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoFree"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoFree
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An AbstractAttribute for noreturn.
struct AANoReturn
: public IRAttribute<Attribute::NoReturn,
StateWrapper<BooleanState, AbstractAttribute>> {
AANoReturn(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if the underlying object is assumed to never return.
bool isAssumedNoReturn() const { return getAssumed(); }
/// Return true if the underlying object is known to never return.
bool isKnownNoReturn() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANoReturn &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoReturn"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoReturn
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for liveness abstract attribute.
struct AAIsDead
: public StateWrapper<BitIntegerState<uint8_t, 3, 0>, AbstractAttribute> {
using Base = StateWrapper<BitIntegerState<uint8_t, 3, 0>, AbstractAttribute>;
AAIsDead(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// State encoding bits. A set bit in the state means the property holds.
enum {
HAS_NO_EFFECT = 1 << 0,
IS_REMOVABLE = 1 << 1,
IS_DEAD = HAS_NO_EFFECT | IS_REMOVABLE,
};
static_assert(IS_DEAD == getBestState(), "Unexpected BEST_STATE value");
protected:
/// The query functions are protected such that other attributes need to go
/// through the Attributor interfaces: `Attributor::isAssumedDead(...)`
/// Returns true if the underlying value is assumed dead.
virtual bool isAssumedDead() const = 0;
/// Returns true if the underlying value is known dead.
virtual bool isKnownDead() const = 0;
/// Returns true if \p BB is assumed dead.
virtual bool isAssumedDead(const BasicBlock *BB) const = 0;
/// Returns true if \p BB is known dead.
virtual bool isKnownDead(const BasicBlock *BB) const = 0;
/// Returns true if \p I is assumed dead.
virtual bool isAssumedDead(const Instruction *I) const = 0;
/// Returns true if \p I is known dead.
virtual bool isKnownDead(const Instruction *I) const = 0;
/// This method is used to check if at least one instruction in a collection
/// of instructions is live.
template <typename T> bool isLiveInstSet(T begin, T end) const {
for (const auto &I : llvm::make_range(begin, end)) {
assert(I->getFunction() == getIRPosition().getAssociatedFunction() &&
"Instruction must be in the same anchor scope function.");
if (!isAssumedDead(I))
return true;
}
return false;
}
public:
/// Create an abstract attribute view for the position \p IRP.
static AAIsDead &createForPosition(const IRPosition &IRP, Attributor &A);
/// Determine if \p F might catch asynchronous exceptions.
static bool mayCatchAsynchronousExceptions(const Function &F) {
return F.hasPersonalityFn() && !canSimplifyInvokeNoUnwind(&F);
}
/// Return if the edge from \p From BB to \p To BB is assumed dead.
/// This is specifically useful in AAReachability.
virtual bool isEdgeDead(const BasicBlock *From, const BasicBlock *To) const {
return false;
}
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAIsDead"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AAIsDead
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
friend struct Attributor;
};
/// State for dereferenceable attribute
struct DerefState : AbstractState {
static DerefState getBestState() { return DerefState(); }
static DerefState getBestState(const DerefState &) { return getBestState(); }
/// Return the worst possible representable state.
static DerefState getWorstState() {
DerefState DS;
DS.indicatePessimisticFixpoint();
return DS;
}
static DerefState getWorstState(const DerefState &) {
return getWorstState();
}
/// State representing for dereferenceable bytes.
IncIntegerState<> DerefBytesState;
/// Map representing for accessed memory offsets and sizes.
/// A key is Offset and a value is size.
/// If there is a load/store instruction something like,
/// p[offset] = v;
/// (offset, sizeof(v)) will be inserted to this map.
/// std::map is used because we want to iterate keys in ascending order.
std::map<int64_t, uint64_t> AccessedBytesMap;
/// Helper function to calculate dereferenceable bytes from current known
/// bytes and accessed bytes.
///
/// int f(int *A){
/// *A = 0;
/// *(A+2) = 2;
/// *(A+1) = 1;
/// *(A+10) = 10;
/// }
/// ```
/// In that case, AccessedBytesMap is `{0:4, 4:4, 8:4, 40:4}`.
/// AccessedBytesMap is std::map so it is iterated in accending order on
/// key(Offset). So KnownBytes will be updated like this:
///
/// |Access | KnownBytes
/// |(0, 4)| 0 -> 4
/// |(4, 4)| 4 -> 8
/// |(8, 4)| 8 -> 12
/// |(40, 4) | 12 (break)
void computeKnownDerefBytesFromAccessedMap() {
int64_t KnownBytes = DerefBytesState.getKnown();
for (auto &Access : AccessedBytesMap) {
if (KnownBytes < Access.first)
break;
KnownBytes = std::max(KnownBytes, Access.first + (int64_t)Access.second);
}
DerefBytesState.takeKnownMaximum(KnownBytes);
}
/// State representing that whether the value is globaly dereferenceable.
BooleanState GlobalState;
/// See AbstractState::isValidState()
bool isValidState() const override { return DerefBytesState.isValidState(); }
/// See AbstractState::isAtFixpoint()
bool isAtFixpoint() const override {
return !isValidState() ||
(DerefBytesState.isAtFixpoint() && GlobalState.isAtFixpoint());
}
/// See AbstractState::indicateOptimisticFixpoint(...)
ChangeStatus indicateOptimisticFixpoint() override {
DerefBytesState.indicateOptimisticFixpoint();
GlobalState.indicateOptimisticFixpoint();
return ChangeStatus::UNCHANGED;
}
/// See AbstractState::indicatePessimisticFixpoint(...)
ChangeStatus indicatePessimisticFixpoint() override {
DerefBytesState.indicatePessimisticFixpoint();
GlobalState.indicatePessimisticFixpoint();
return ChangeStatus::CHANGED;
}
/// Update known dereferenceable bytes.
void takeKnownDerefBytesMaximum(uint64_t Bytes) {
DerefBytesState.takeKnownMaximum(Bytes);
// Known bytes might increase.
computeKnownDerefBytesFromAccessedMap();
}
/// Update assumed dereferenceable bytes.
void takeAssumedDerefBytesMinimum(uint64_t Bytes) {
DerefBytesState.takeAssumedMinimum(Bytes);
}
/// Add accessed bytes to the map.
void addAccessedBytes(int64_t Offset, uint64_t Size) {
uint64_t &AccessedBytes = AccessedBytesMap[Offset];
AccessedBytes = std::max(AccessedBytes, Size);
// Known bytes might increase.
computeKnownDerefBytesFromAccessedMap();
}
/// Equality for DerefState.
bool operator==(const DerefState &R) const {
return this->DerefBytesState == R.DerefBytesState &&
this->GlobalState == R.GlobalState;
}
/// Inequality for DerefState.
bool operator!=(const DerefState &R) const { return !(*this == R); }
/// See IntegerStateBase::operator^=
DerefState operator^=(const DerefState &R) {
DerefBytesState ^= R.DerefBytesState;
GlobalState ^= R.GlobalState;
return *this;
}
/// See IntegerStateBase::operator+=
DerefState operator+=(const DerefState &R) {
DerefBytesState += R.DerefBytesState;
GlobalState += R.GlobalState;
return *this;
}
/// See IntegerStateBase::operator&=
DerefState operator&=(const DerefState &R) {
DerefBytesState &= R.DerefBytesState;
GlobalState &= R.GlobalState;
return *this;
}
/// See IntegerStateBase::operator|=
DerefState operator|=(const DerefState &R) {
DerefBytesState |= R.DerefBytesState;
GlobalState |= R.GlobalState;
return *this;
}
protected:
const AANonNull *NonNullAA = nullptr;
};
/// An abstract interface for all dereferenceable attribute.
struct AADereferenceable
: public IRAttribute<Attribute::Dereferenceable,
StateWrapper<DerefState, AbstractAttribute>> {
AADereferenceable(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if we assume that the underlying value is nonnull.
bool isAssumedNonNull() const {
return NonNullAA && NonNullAA->isAssumedNonNull();
}
/// Return true if we know that the underlying value is nonnull.
bool isKnownNonNull() const {
return NonNullAA && NonNullAA->isKnownNonNull();
}
/// Return true if we assume that underlying value is
/// dereferenceable(_or_null) globally.
bool isAssumedGlobal() const { return GlobalState.getAssumed(); }
/// Return true if we know that underlying value is
/// dereferenceable(_or_null) globally.
bool isKnownGlobal() const { return GlobalState.getKnown(); }
/// Return assumed dereferenceable bytes.
uint32_t getAssumedDereferenceableBytes() const {
return DerefBytesState.getAssumed();
}
/// Return known dereferenceable bytes.
uint32_t getKnownDereferenceableBytes() const {
return DerefBytesState.getKnown();
}
/// Create an abstract attribute view for the position \p IRP.
static AADereferenceable &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AADereferenceable"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AADereferenceable
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
using AAAlignmentStateType =
IncIntegerState<uint32_t, Value::MaximumAlignment, 1>;
/// An abstract interface for all align attributes.
struct AAAlign : public IRAttribute<
Attribute::Alignment,
StateWrapper<AAAlignmentStateType, AbstractAttribute>> {
AAAlign(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return assumed alignment.
unsigned getAssumedAlign() const { return getAssumed(); }
/// Return known alignment.
unsigned getKnownAlign() const { return getKnown(); }
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAAlign"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AAAlign
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Create an abstract attribute view for the position \p IRP.
static AAAlign &createForPosition(const IRPosition &IRP, Attributor &A);
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for all nocapture attributes.
struct AANoCapture
: public IRAttribute<
Attribute::NoCapture,
StateWrapper<BitIntegerState<uint16_t, 7, 0>, AbstractAttribute>> {
AANoCapture(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// State encoding bits. A set bit in the state means the property holds.
/// NO_CAPTURE is the best possible state, 0 the worst possible state.
enum {
NOT_CAPTURED_IN_MEM = 1 << 0,
NOT_CAPTURED_IN_INT = 1 << 1,
NOT_CAPTURED_IN_RET = 1 << 2,
/// If we do not capture the value in memory or through integers we can only
/// communicate it back as a derived pointer.
NO_CAPTURE_MAYBE_RETURNED = NOT_CAPTURED_IN_MEM | NOT_CAPTURED_IN_INT,
/// If we do not capture the value in memory, through integers, or as a
/// derived pointer we know it is not captured.
NO_CAPTURE =
NOT_CAPTURED_IN_MEM | NOT_CAPTURED_IN_INT | NOT_CAPTURED_IN_RET,
};
/// Return true if we know that the underlying value is not captured in its
/// respective scope.
bool isKnownNoCapture() const { return isKnown(NO_CAPTURE); }
/// Return true if we assume that the underlying value is not captured in its
/// respective scope.
bool isAssumedNoCapture() const { return isAssumed(NO_CAPTURE); }
/// Return true if we know that the underlying value is not captured in its
/// respective scope but we allow it to escape through a "return".
bool isKnownNoCaptureMaybeReturned() const {
return isKnown(NO_CAPTURE_MAYBE_RETURNED);
}
/// Return true if we assume that the underlying value is not captured in its
/// respective scope but we allow it to escape through a "return".
bool isAssumedNoCaptureMaybeReturned() const {
return isAssumed(NO_CAPTURE_MAYBE_RETURNED);
}
/// Create an abstract attribute view for the position \p IRP.
static AANoCapture &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoCapture"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoCapture
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
struct ValueSimplifyStateType : public AbstractState {
ValueSimplifyStateType(Type *Ty) : Ty(Ty) {}
static ValueSimplifyStateType getBestState(Type *Ty) {
return ValueSimplifyStateType(Ty);
}
static ValueSimplifyStateType getBestState(const ValueSimplifyStateType &VS) {
return getBestState(VS.Ty);
}
/// Return the worst possible representable state.
static ValueSimplifyStateType getWorstState(Type *Ty) {
ValueSimplifyStateType DS(Ty);
DS.indicatePessimisticFixpoint();
return DS;
}
static ValueSimplifyStateType
getWorstState(const ValueSimplifyStateType &VS) {
return getWorstState(VS.Ty);
}
/// See AbstractState::isValidState(...)
bool isValidState() const override { return BS.isValidState(); }
/// See AbstractState::isAtFixpoint(...)
bool isAtFixpoint() const override { return BS.isAtFixpoint(); }
/// Return the assumed state encoding.
ValueSimplifyStateType getAssumed() { return *this; }
const ValueSimplifyStateType &getAssumed() const { return *this; }
/// See AbstractState::indicatePessimisticFixpoint(...)
ChangeStatus indicatePessimisticFixpoint() override {
return BS.indicatePessimisticFixpoint();
}
/// See AbstractState::indicateOptimisticFixpoint(...)
ChangeStatus indicateOptimisticFixpoint() override {
return BS.indicateOptimisticFixpoint();
}
/// "Clamp" this state with \p PVS.
ValueSimplifyStateType operator^=(const ValueSimplifyStateType &VS) {
BS ^= VS.BS;
unionAssumed(VS.SimplifiedAssociatedValue);
return *this;
}
bool operator==(const ValueSimplifyStateType &RHS) const {
if (isValidState() != RHS.isValidState())
return false;
if (!isValidState() && !RHS.isValidState())
return true;
return SimplifiedAssociatedValue == RHS.SimplifiedAssociatedValue;
}
protected:
/// The type of the original value.
Type *Ty;
/// Merge \p Other into the currently assumed simplified value
bool unionAssumed(Optional<Value *> Other);
/// Helper to track validity and fixpoint
BooleanState BS;
/// An assumed simplified value. Initially, it is set to Optional::None, which
/// means that the value is not clear under current assumption. If in the
/// pessimistic state, getAssumedSimplifiedValue doesn't return this value but
/// returns orignal associated value.
Optional<Value *> SimplifiedAssociatedValue;
};
/// An abstract interface for value simplify abstract attribute.
struct AAValueSimplify
: public StateWrapper<ValueSimplifyStateType, AbstractAttribute, Type *> {
using Base = StateWrapper<ValueSimplifyStateType, AbstractAttribute, Type *>;
AAValueSimplify(const IRPosition &IRP, Attributor &A)
: Base(IRP, IRP.getAssociatedType()) {}
/// Create an abstract attribute view for the position \p IRP.
static AAValueSimplify &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAValueSimplify"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAValueSimplify
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
private:
/// Return an assumed simplified value if a single candidate is found. If
/// there cannot be one, return original value. If it is not clear yet, return
/// the Optional::NoneType.
///
/// Use `Attributor::getAssumedSimplified` for value simplification.
virtual Optional<Value *> getAssumedSimplifiedValue(Attributor &A) const = 0;
friend struct Attributor;
};
struct AAHeapToStack : public StateWrapper<BooleanState, AbstractAttribute> {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AAHeapToStack(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// Returns true if HeapToStack conversion is assumed to be possible.
virtual bool isAssumedHeapToStack(const CallBase &CB) const = 0;
/// Returns true if HeapToStack conversion is assumed and the CB is a
/// callsite to a free operation to be removed.
virtual bool isAssumedHeapToStackRemovedFree(CallBase &CB) const = 0;
/// Create an abstract attribute view for the position \p IRP.
static AAHeapToStack &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAHeapToStack"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AAHeapToStack
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for privatizability.
///
/// A pointer is privatizable if it can be replaced by a new, private one.
/// Privatizing pointer reduces the use count, interaction between unrelated
/// code parts.
///
/// In order for a pointer to be privatizable its value cannot be observed
/// (=nocapture), it is (for now) not written (=readonly & noalias), we know
/// what values are necessary to make the private copy look like the original
/// one, and the values we need can be loaded (=dereferenceable).
struct AAPrivatizablePtr
: public StateWrapper<BooleanState, AbstractAttribute> {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AAPrivatizablePtr(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// Returns true if pointer privatization is assumed to be possible.
bool isAssumedPrivatizablePtr() const { return getAssumed(); }
/// Returns true if pointer privatization is known to be possible.
bool isKnownPrivatizablePtr() const { return getKnown(); }
/// Return the type we can choose for a private copy of the underlying
/// value. None means it is not clear yet, nullptr means there is none.
virtual Optional<Type *> getPrivatizableType() const = 0;
/// Create an abstract attribute view for the position \p IRP.
static AAPrivatizablePtr &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAPrivatizablePtr"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAPricatizablePtr
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for memory access kind related attributes
/// (readnone/readonly/writeonly).
struct AAMemoryBehavior
: public IRAttribute<
Attribute::ReadNone,
StateWrapper<BitIntegerState<uint8_t, 3>, AbstractAttribute>> {
AAMemoryBehavior(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// State encoding bits. A set bit in the state means the property holds.
/// BEST_STATE is the best possible state, 0 the worst possible state.
enum {
NO_READS = 1 << 0,
NO_WRITES = 1 << 1,
NO_ACCESSES = NO_READS | NO_WRITES,
BEST_STATE = NO_ACCESSES,
};
static_assert(BEST_STATE == getBestState(), "Unexpected BEST_STATE value");
/// Return true if we know that the underlying value is not read or accessed
/// in its respective scope.
bool isKnownReadNone() const { return isKnown(NO_ACCESSES); }
/// Return true if we assume that the underlying value is not read or accessed
/// in its respective scope.
bool isAssumedReadNone() const { return isAssumed(NO_ACCESSES); }
/// Return true if we know that the underlying value is not accessed
/// (=written) in its respective scope.
bool isKnownReadOnly() const { return isKnown(NO_WRITES); }
/// Return true if we assume that the underlying value is not accessed
/// (=written) in its respective scope.
bool isAssumedReadOnly() const { return isAssumed(NO_WRITES); }
/// Return true if we know that the underlying value is not read in its
/// respective scope.
bool isKnownWriteOnly() const { return isKnown(NO_READS); }
/// Return true if we assume that the underlying value is not read in its
/// respective scope.
bool isAssumedWriteOnly() const { return isAssumed(NO_READS); }
/// Create an abstract attribute view for the position \p IRP.
static AAMemoryBehavior &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAMemoryBehavior"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAMemoryBehavior
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for all memory location attributes
/// (readnone/argmemonly/inaccessiblememonly/inaccessibleorargmemonly).
struct AAMemoryLocation
: public IRAttribute<
Attribute::ReadNone,
StateWrapper<BitIntegerState<uint32_t, 511>, AbstractAttribute>> {
using MemoryLocationsKind = StateType::base_t;
AAMemoryLocation(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Encoding of different locations that could be accessed by a memory
/// access.
enum {
ALL_LOCATIONS = 0,
NO_LOCAL_MEM = 1 << 0,
NO_CONST_MEM = 1 << 1,
NO_GLOBAL_INTERNAL_MEM = 1 << 2,
NO_GLOBAL_EXTERNAL_MEM = 1 << 3,
NO_GLOBAL_MEM = NO_GLOBAL_INTERNAL_MEM | NO_GLOBAL_EXTERNAL_MEM,
NO_ARGUMENT_MEM = 1 << 4,
NO_INACCESSIBLE_MEM = 1 << 5,
NO_MALLOCED_MEM = 1 << 6,
NO_UNKOWN_MEM = 1 << 7,
NO_LOCATIONS = NO_LOCAL_MEM | NO_CONST_MEM | NO_GLOBAL_INTERNAL_MEM |
NO_GLOBAL_EXTERNAL_MEM | NO_ARGUMENT_MEM |
NO_INACCESSIBLE_MEM | NO_MALLOCED_MEM | NO_UNKOWN_MEM,
// Helper bit to track if we gave up or not.
VALID_STATE = NO_LOCATIONS + 1,
BEST_STATE = NO_LOCATIONS | VALID_STATE,
};
static_assert(BEST_STATE == getBestState(), "Unexpected BEST_STATE value");
/// Return true if we know that the associated functions has no observable
/// accesses.
bool isKnownReadNone() const { return isKnown(NO_LOCATIONS); }
/// Return true if we assume that the associated functions has no observable
/// accesses.
bool isAssumedReadNone() const {
return isAssumed(NO_LOCATIONS) | isAssumedStackOnly();
}
/// Return true if we know that the associated functions has at most
/// local/stack accesses.
bool isKnowStackOnly() const {
return isKnown(inverseLocation(NO_LOCAL_MEM, true, true));
}
/// Return true if we assume that the associated functions has at most
/// local/stack accesses.
bool isAssumedStackOnly() const {
return isAssumed(inverseLocation(NO_LOCAL_MEM, true, true));
}
/// Return true if we know that the underlying value will only access
/// inaccesible memory only (see Attribute::InaccessibleMemOnly).
bool isKnownInaccessibleMemOnly() const {
return isKnown(inverseLocation(NO_INACCESSIBLE_MEM, true, true));
}
/// Return true if we assume that the underlying value will only access
/// inaccesible memory only (see Attribute::InaccessibleMemOnly).
bool isAssumedInaccessibleMemOnly() const {
return isAssumed(inverseLocation(NO_INACCESSIBLE_MEM, true, true));
}
/// Return true if we know that the underlying value will only access
/// argument pointees (see Attribute::ArgMemOnly).
bool isKnownArgMemOnly() const {
return isKnown(inverseLocation(NO_ARGUMENT_MEM, true, true));
}
/// Return true if we assume that the underlying value will only access
/// argument pointees (see Attribute::ArgMemOnly).
bool isAssumedArgMemOnly() const {
return isAssumed(inverseLocation(NO_ARGUMENT_MEM, true, true));
}
/// Return true if we know that the underlying value will only access
/// inaccesible memory or argument pointees (see
/// Attribute::InaccessibleOrArgMemOnly).
bool isKnownInaccessibleOrArgMemOnly() const {
return isKnown(
inverseLocation(NO_INACCESSIBLE_MEM | NO_ARGUMENT_MEM, true, true));
}
/// Return true if we assume that the underlying value will only access
/// inaccesible memory or argument pointees (see
/// Attribute::InaccessibleOrArgMemOnly).
bool isAssumedInaccessibleOrArgMemOnly() const {
return isAssumed(
inverseLocation(NO_INACCESSIBLE_MEM | NO_ARGUMENT_MEM, true, true));
}
/// Return true if the underlying value may access memory through arguement
/// pointers of the associated function, if any.
bool mayAccessArgMem() const { return !isAssumed(NO_ARGUMENT_MEM); }
/// Return true if only the memory locations specififed by \p MLK are assumed
/// to be accessed by the associated function.
bool isAssumedSpecifiedMemOnly(MemoryLocationsKind MLK) const {
return isAssumed(MLK);
}
/// Return the locations that are assumed to be not accessed by the associated
/// function, if any.
MemoryLocationsKind getAssumedNotAccessedLocation() const {
return getAssumed();
}
/// Return the inverse of location \p Loc, thus for NO_XXX the return
/// describes ONLY_XXX. The flags \p AndLocalMem and \p AndConstMem determine
/// if local (=stack) and constant memory are allowed as well. Most of the
/// time we do want them to be included, e.g., argmemonly allows accesses via
/// argument pointers or local or constant memory accesses.
static MemoryLocationsKind
inverseLocation(MemoryLocationsKind Loc, bool AndLocalMem, bool AndConstMem) {
return NO_LOCATIONS & ~(Loc | (AndLocalMem ? NO_LOCAL_MEM : 0) |
(AndConstMem ? NO_CONST_MEM : 0));
};
/// Return the locations encoded by \p MLK as a readable string.
static std::string getMemoryLocationsAsStr(MemoryLocationsKind MLK);
/// Simple enum to distinguish read/write/read-write accesses.
enum AccessKind {
NONE = 0,
READ = 1 << 0,
WRITE = 1 << 1,
READ_WRITE = READ | WRITE,
};
/// Check \p Pred on all accesses to the memory kinds specified by \p MLK.
///
/// This method will evaluate \p Pred on all accesses (access instruction +
/// underlying accessed memory pointer) and it will return true if \p Pred
/// holds every time.
virtual bool checkForAllAccessesToMemoryKind(
function_ref<bool(const Instruction *, const Value *, AccessKind,
MemoryLocationsKind)>
Pred,
MemoryLocationsKind MLK) const = 0;
/// Create an abstract attribute view for the position \p IRP.
static AAMemoryLocation &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractState::getAsStr().
const std::string getAsStr() const override {
return getMemoryLocationsAsStr(getAssumedNotAccessedLocation());
}
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAMemoryLocation"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAMemoryLocation
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for range value analysis.
struct AAValueConstantRange
: public StateWrapper<IntegerRangeState, AbstractAttribute, uint32_t> {
using Base = StateWrapper<IntegerRangeState, AbstractAttribute, uint32_t>;
AAValueConstantRange(const IRPosition &IRP, Attributor &A)
: Base(IRP, IRP.getAssociatedType()->getIntegerBitWidth()) {}
/// See AbstractAttribute::getState(...).
IntegerRangeState &getState() override { return *this; }
const IntegerRangeState &getState() const override { return *this; }
/// Create an abstract attribute view for the position \p IRP.
static AAValueConstantRange &createForPosition(const IRPosition &IRP,
Attributor &A);
/// Return an assumed range for the assocaited value a program point \p CtxI.
/// If \p I is nullptr, simply return an assumed range.
virtual ConstantRange
getAssumedConstantRange(Attributor &A,
const Instruction *CtxI = nullptr) const = 0;
/// Return a known range for the assocaited value at a program point \p CtxI.
/// If \p I is nullptr, simply return a known range.
virtual ConstantRange
getKnownConstantRange(Attributor &A,
const Instruction *CtxI = nullptr) const = 0;
/// Return an assumed constant for the assocaited value a program point \p
/// CtxI.
Optional<ConstantInt *>
getAssumedConstantInt(Attributor &A,
const Instruction *CtxI = nullptr) const {
ConstantRange RangeV = getAssumedConstantRange(A, CtxI);
if (auto *C = RangeV.getSingleElement())
return cast<ConstantInt>(
ConstantInt::get(getAssociatedValue().getType(), *C));
if (RangeV.isEmptySet())
return llvm::None;
return nullptr;
}
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAValueConstantRange"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAValueConstantRange
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// A class for a set state.
/// The assumed boolean state indicates whether the corresponding set is full
/// set or not. If the assumed state is false, this is the worst state. The
/// worst state (invalid state) of set of potential values is when the set
/// contains every possible value (i.e. we cannot in any way limit the value
/// that the target position can take). That never happens naturally, we only
/// force it. As for the conditions under which we force it, see
/// AAPotentialValues.
template <typename MemberTy, typename KeyInfo = DenseMapInfo<MemberTy>>
struct PotentialValuesState : AbstractState {
using SetTy = DenseSet<MemberTy, KeyInfo>;
PotentialValuesState() : IsValidState(true), UndefIsContained(false) {}
PotentialValuesState(bool IsValid)
: IsValidState(IsValid), UndefIsContained(false) {}
/// See AbstractState::isValidState(...)
bool isValidState() const override { return IsValidState.isValidState(); }
/// See AbstractState::isAtFixpoint(...)
bool isAtFixpoint() const override { return IsValidState.isAtFixpoint(); }
/// See AbstractState::indicatePessimisticFixpoint(...)
ChangeStatus indicatePessimisticFixpoint() override {
return IsValidState.indicatePessimisticFixpoint();
}
/// See AbstractState::indicateOptimisticFixpoint(...)
ChangeStatus indicateOptimisticFixpoint() override {
return IsValidState.indicateOptimisticFixpoint();
}
/// Return the assumed state
PotentialValuesState &getAssumed() { return *this; }
const PotentialValuesState &getAssumed() const { return *this; }
/// Return this set. We should check whether this set is valid or not by
/// isValidState() before calling this function.
const SetTy &getAssumedSet() const {
assert(isValidState() && "This set shoud not be used when it is invalid!");
return Set;
}
/// Returns whether this state contains an undef value or not.
bool undefIsContained() const {
assert(isValidState() && "This flag shoud not be used when it is invalid!");
return UndefIsContained;
}
bool operator==(const PotentialValuesState &RHS) const {
if (isValidState() != RHS.isValidState())
return false;
if (!isValidState() && !RHS.isValidState())
return true;
if (undefIsContained() != RHS.undefIsContained())
return false;
return Set == RHS.getAssumedSet();
}
/// Maximum number of potential values to be tracked.
/// This is set by -attributor-max-potential-values command line option
static unsigned MaxPotentialValues;
/// Return empty set as the best state of potential values.
static PotentialValuesState getBestState() {
return PotentialValuesState(true);
}
static PotentialValuesState getBestState(PotentialValuesState &PVS) {
return getBestState();
}
/// Return full set as the worst state of potential values.
static PotentialValuesState getWorstState() {
return PotentialValuesState(false);
}
/// Union assumed set with the passed value.
void unionAssumed(const MemberTy &C) { insert(C); }
/// Union assumed set with assumed set of the passed state \p PVS.
void unionAssumed(const PotentialValuesState &PVS) { unionWith(PVS); }
/// Union assumed set with an undef value.
void unionAssumedWithUndef() { unionWithUndef(); }
/// "Clamp" this state with \p PVS.
PotentialValuesState operator^=(const PotentialValuesState &PVS) {
IsValidState ^= PVS.IsValidState;
unionAssumed(PVS);
return *this;
}
PotentialValuesState operator&=(const PotentialValuesState &PVS) {
IsValidState &= PVS.IsValidState;
unionAssumed(PVS);
return *this;
}
private:
/// Check the size of this set, and invalidate when the size is no
/// less than \p MaxPotentialValues threshold.
void checkAndInvalidate() {
if (Set.size() >= MaxPotentialValues)
indicatePessimisticFixpoint();
else
reduceUndefValue();
}
/// If this state contains both undef and not undef, we can reduce
/// undef to the not undef value.
void reduceUndefValue() { UndefIsContained = UndefIsContained & Set.empty(); }
/// Insert an element into this set.
void insert(const MemberTy &C) {
if (!isValidState())
return;
Set.insert(C);
checkAndInvalidate();
}
/// Take union with R.
void unionWith(const PotentialValuesState &R) {
/// If this is a full set, do nothing.
if (!isValidState())
return;
/// If R is full set, change L to a full set.
if (!R.isValidState()) {
indicatePessimisticFixpoint();
return;
}
for (const MemberTy &C : R.Set)
Set.insert(C);
UndefIsContained |= R.undefIsContained();
checkAndInvalidate();
}
/// Take union with an undef value.
void unionWithUndef() {
UndefIsContained = true;
reduceUndefValue();
}
/// Take intersection with R.
void intersectWith(const PotentialValuesState &R) {
/// If R is a full set, do nothing.
if (!R.isValidState())
return;
/// If this is a full set, change this to R.
if (!isValidState()) {
*this = R;
return;
}
SetTy IntersectSet;
for (const MemberTy &C : Set) {
if (R.Set.count(C))
IntersectSet.insert(C);
}
Set = IntersectSet;
UndefIsContained &= R.undefIsContained();
reduceUndefValue();
}
/// A helper state which indicate whether this state is valid or not.
BooleanState IsValidState;
/// Container for potential values
SetTy Set;
/// Flag for undef value
bool UndefIsContained;
};
using PotentialConstantIntValuesState = PotentialValuesState<APInt>;
raw_ostream &operator<<(raw_ostream &OS,
const PotentialConstantIntValuesState &R);
/// An abstract interface for potential values analysis.
///
/// This AA collects potential values for each IR position.
/// An assumed set of potential values is initialized with the empty set (the
/// best state) and it will grow monotonically as we find more potential values
/// for this position.
/// The set might be forced to the worst state, that is, to contain every
/// possible value for this position in 2 cases.
/// 1. We surpassed the \p MaxPotentialValues threshold. This includes the
/// case that this position is affected (e.g. because of an operation) by a
/// Value that is in the worst state.
/// 2. We tried to initialize on a Value that we cannot handle (e.g. an
/// operator we do not currently handle).
///
/// TODO: Support values other than constant integers.
struct AAPotentialValues
: public StateWrapper<PotentialConstantIntValuesState, AbstractAttribute> {
using Base = StateWrapper<PotentialConstantIntValuesState, AbstractAttribute>;
AAPotentialValues(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// See AbstractAttribute::getState(...).
PotentialConstantIntValuesState &getState() override { return *this; }
const PotentialConstantIntValuesState &getState() const override {
return *this;
}
/// Create an abstract attribute view for the position \p IRP.
static AAPotentialValues &createForPosition(const IRPosition &IRP,
Attributor &A);
/// Return assumed constant for the associated value
Optional<ConstantInt *>
getAssumedConstantInt(Attributor &A,
const Instruction *CtxI = nullptr) const {
if (!isValidState())
return nullptr;
if (getAssumedSet().size() == 1)
return cast<ConstantInt>(ConstantInt::get(getAssociatedValue().getType(),
*(getAssumedSet().begin())));
if (getAssumedSet().size() == 0) {
if (undefIsContained())
return cast<ConstantInt>(
ConstantInt::get(getAssociatedValue().getType(), 0));
return llvm::None;
}
return nullptr;
}
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAPotentialValues"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is
/// AAPotentialValues
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract interface for all noundef attributes.
struct AANoUndef
: public IRAttribute<Attribute::NoUndef,
StateWrapper<BooleanState, AbstractAttribute>> {
AANoUndef(const IRPosition &IRP, Attributor &A) : IRAttribute(IRP) {}
/// Return true if we assume that the underlying value is noundef.
bool isAssumedNoUndef() const { return getAssumed(); }
/// Return true if we know that underlying value is noundef.
bool isKnownNoUndef() const { return getKnown(); }
/// Create an abstract attribute view for the position \p IRP.
static AANoUndef &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AANoUndef"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AANoUndef
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
struct AACallGraphNode;
struct AACallEdges;
/// An Iterator for call edges, creates AACallEdges attributes in a lazy way.
/// This iterator becomes invalid if the underlying edge list changes.
/// So This shouldn't outlive a iteration of Attributor.
class AACallEdgeIterator
: public iterator_adaptor_base<AACallEdgeIterator,
SetVector<Function *>::iterator> {
AACallEdgeIterator(Attributor &A, SetVector<Function *>::iterator Begin)
: iterator_adaptor_base(Begin), A(A) {}
public:
AACallGraphNode *operator*() const;
private:
Attributor &A;
friend AACallEdges;
friend AttributorCallGraph;
};
struct AACallGraphNode {
AACallGraphNode(Attributor &A) : A(A) {}
virtual ~AACallGraphNode() {}
virtual AACallEdgeIterator optimisticEdgesBegin() const = 0;
virtual AACallEdgeIterator optimisticEdgesEnd() const = 0;
/// Iterator range for exploring the call graph.
iterator_range<AACallEdgeIterator> optimisticEdgesRange() const {
return iterator_range<AACallEdgeIterator>(optimisticEdgesBegin(),
optimisticEdgesEnd());
}
protected:
/// Reference to Attributor needed for GraphTraits implementation.
Attributor &A;
};
/// An abstract state for querying live call edges.
/// This interface uses the Attributor's optimistic liveness
/// information to compute the edges that are alive.
struct AACallEdges : public StateWrapper<BooleanState, AbstractAttribute>,
AACallGraphNode {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AACallEdges(const IRPosition &IRP, Attributor &A)
: Base(IRP), AACallGraphNode(A) {}
/// Get the optimistic edges.
virtual const SetVector<Function *> &getOptimisticEdges() const = 0;
/// Is there any call with a unknown callee.
virtual bool hasUnknownCallee() const = 0;
/// Is there any call with a unknown callee, excluding any inline asm.
virtual bool hasNonAsmUnknownCallee() const = 0;
/// Iterator for exploring the call graph.
AACallEdgeIterator optimisticEdgesBegin() const override {
return AACallEdgeIterator(A, getOptimisticEdges().begin());
}
/// Iterator for exploring the call graph.
AACallEdgeIterator optimisticEdgesEnd() const override {
return AACallEdgeIterator(A, getOptimisticEdges().end());
}
/// Create an abstract attribute view for the position \p IRP.
static AACallEdges &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AACallEdges"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AACallEdges.
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
// Synthetic root node for the Attributor's internal call graph.
struct AttributorCallGraph : public AACallGraphNode {
AttributorCallGraph(Attributor &A) : AACallGraphNode(A) {}
virtual ~AttributorCallGraph() {}
AACallEdgeIterator optimisticEdgesBegin() const override {
return AACallEdgeIterator(A, A.Functions.begin());
}
AACallEdgeIterator optimisticEdgesEnd() const override {
return AACallEdgeIterator(A, A.Functions.end());
}
/// Force populate the entire call graph.
void populateAll() const {
for (const AACallGraphNode *AA : optimisticEdgesRange()) {
// Nothing else to do here.
(void)AA;
}
}
void print();
};
template <> struct GraphTraits<AACallGraphNode *> {
using NodeRef = AACallGraphNode *;
using ChildIteratorType = AACallEdgeIterator;
static AACallEdgeIterator child_begin(AACallGraphNode *Node) {
return Node->optimisticEdgesBegin();
}
static AACallEdgeIterator child_end(AACallGraphNode *Node) {
return Node->optimisticEdgesEnd();
}
};
template <>
struct GraphTraits<AttributorCallGraph *>
: public GraphTraits<AACallGraphNode *> {
using nodes_iterator = AACallEdgeIterator;
static AACallGraphNode *getEntryNode(AttributorCallGraph *G) {
return static_cast<AACallGraphNode *>(G);
}
static AACallEdgeIterator nodes_begin(const AttributorCallGraph *G) {
return G->optimisticEdgesBegin();
}
static AACallEdgeIterator nodes_end(const AttributorCallGraph *G) {
return G->optimisticEdgesEnd();
}
};
template <>
struct DOTGraphTraits<AttributorCallGraph *> : public DefaultDOTGraphTraits {
DOTGraphTraits(bool Simple = false) : DefaultDOTGraphTraits(Simple) {}
std::string getNodeLabel(const AACallGraphNode *Node,
const AttributorCallGraph *Graph) {
const AACallEdges *AACE = static_cast<const AACallEdges *>(Node);
return AACE->getAssociatedFunction()->getName().str();
}
static bool isNodeHidden(const AACallGraphNode *Node,
const AttributorCallGraph *Graph) {
// Hide the synth root.
return static_cast<const AACallGraphNode *>(Graph) == Node;
}
};
struct AAExecutionDomain
: public StateWrapper<BooleanState, AbstractAttribute> {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AAExecutionDomain(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// Create an abstract attribute view for the position \p IRP.
static AAExecutionDomain &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName().
const std::string getName() const override { return "AAExecutionDomain"; }
/// See AbstractAttribute::getIdAddr().
const char *getIdAddr() const override { return &ID; }
/// Check if an instruction is executed only by the initial thread.
virtual bool isExecutedByInitialThreadOnly(const Instruction &) const = 0;
/// Check if a basic block is executed only by the initial thread.
virtual bool isExecutedByInitialThreadOnly(const BasicBlock &) const = 0;
/// This function should return true if the type of the \p AA is
/// AAExecutionDomain.
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
/// An abstract Attribute for computing reachability between functions.
struct AAFunctionReachability
: public StateWrapper<BooleanState, AbstractAttribute> {
using Base = StateWrapper<BooleanState, AbstractAttribute>;
AAFunctionReachability(const IRPosition &IRP, Attributor &A) : Base(IRP) {}
/// If the function represented by this possition can reach \p Fn.
virtual bool canReach(Attributor &A, Function *Fn) const = 0;
/// Create an abstract attribute view for the position \p IRP.
static AAFunctionReachability &createForPosition(const IRPosition &IRP,
Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAFuncitonReacability"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// This function should return true if the type of the \p AA is AACallEdges.
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
private:
/// Can this function reach a call with unknown calee.
virtual bool canReachUnknownCallee() const = 0;
};
/// An abstract interface for struct information.
struct AAPointerInfo : public AbstractAttribute {
AAPointerInfo(const IRPosition &IRP) : AbstractAttribute(IRP) {}
enum AccessKind {
AK_READ = 1 << 0,
AK_WRITE = 1 << 1,
AK_READ_WRITE = AK_READ | AK_WRITE,
};
/// An access description.
struct Access {
Access(Instruction *I, Optional<Value *> Content, AccessKind Kind, Type *Ty)
: LocalI(I), RemoteI(I), Content(Content), Kind(Kind), Ty(Ty) {}
Access(Instruction *LocalI, Instruction *RemoteI, Optional<Value *> Content,
AccessKind Kind, Type *Ty)
: LocalI(LocalI), RemoteI(RemoteI), Content(Content), Kind(Kind),
Ty(Ty) {}
Access(const Access &Other)
: LocalI(Other.LocalI), RemoteI(Other.RemoteI), Content(Other.Content),
Kind(Other.Kind), Ty(Other.Ty) {}
Access(const Access &&Other)
: LocalI(Other.LocalI), RemoteI(Other.RemoteI), Content(Other.Content),
Kind(Other.Kind), Ty(Other.Ty) {}
Access &operator=(const Access &Other) {
LocalI = Other.LocalI;
RemoteI = Other.RemoteI;
Content = Other.Content;
Kind = Other.Kind;
Ty = Other.Ty;
return *this;
}
bool operator==(const Access &R) const {
return LocalI == R.LocalI && RemoteI == R.RemoteI &&
Content == R.Content && Kind == R.Kind;
}
bool operator!=(const Access &R) const { return !(*this == R); }
Access &operator&=(const Access &R) {
assert(RemoteI == R.RemoteI && "Expected same instruction!");
Content =
AA::combineOptionalValuesInAAValueLatice(Content, R.Content, Ty);
Kind = AccessKind(Kind | R.Kind);
return *this;
}
/// Return the access kind.
AccessKind getKind() const { return Kind; }
/// Return true if this is a read access.
bool isRead() const { return Kind & AK_READ; }
/// Return true if this is a write access.
bool isWrite() const { return Kind & AK_WRITE; }
/// Return the instruction that causes the access with respect to the local
/// scope of the associated attribute.
Instruction *getLocalInst() const { return LocalI; }
/// Return the actual instruction that causes the access.
Instruction *getRemoteInst() const { return RemoteI; }
/// Return true if the value written is not known yet.
bool isWrittenValueYetUndetermined() const { return !Content.hasValue(); }
/// Return true if the value written cannot be determined at all.
bool isWrittenValueUnknown() const {
return Content.hasValue() && !*Content;
}
/// Return the type associated with the access, if known.
Type *getType() const { return Ty; }
/// Return the value writen, if any. As long as
/// isWrittenValueYetUndetermined return true this function shall not be
/// called.
Value *getWrittenValue() const { return *Content; }
/// Return the written value which can be `llvm::null` if it is not yet
/// determined.
Optional<Value *> getContent() const { return Content; }
private:
/// The instruction responsible for the access with respect to the local
/// scope of the associated attribute.
Instruction *LocalI;
/// The instruction responsible for the access.
Instruction *RemoteI;
/// The value written, if any. `llvm::none` means "not known yet", `nullptr`
/// cannot be determined.
Optional<Value *> Content;
/// The access kind, e.g., READ, as bitset (could be more than one).
AccessKind Kind;
/// The type of the content, thus the type read/written, can be null if not
/// available.
Type *Ty;
};
/// Create an abstract attribute view for the position \p IRP.
static AAPointerInfo &createForPosition(const IRPosition &IRP, Attributor &A);
/// See AbstractAttribute::getName()
const std::string getName() const override { return "AAPointerInfo"; }
/// See AbstractAttribute::getIdAddr()
const char *getIdAddr() const override { return &ID; }
/// Call \p CB on all accesses that might interfere with \p LI and return true
/// if all such accesses were known and the callback returned true for all of
/// them, false otherwise.
virtual bool forallInterferingAccesses(
LoadInst &LI, function_ref<bool(const Access &, bool)> CB) const = 0;
virtual bool forallInterferingAccesses(
StoreInst &SI, function_ref<bool(const Access &, bool)> CB) const = 0;
/// This function should return true if the type of the \p AA is AAPointerInfo
static bool classof(const AbstractAttribute *AA) {
return (AA->getIdAddr() == &ID);
}
/// Unique ID (due to the unique address)
static const char ID;
};
raw_ostream &operator<<(raw_ostream &, const AAPointerInfo::Access &);
/// Run options, used by the pass manager.
enum AttributorRunOption {
NONE = 0,
MODULE = 1 << 0,
CGSCC = 1 << 1,
ALL = MODULE | CGSCC
};
} // end namespace llvm
#endif // LLVM_TRANSFORMS_IPO_ATTRIBUTOR_H
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