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5f6b30b7c0
llvm-mirror/lib/Analysis/DataStructure/DataStructure.cpp
Chris Lattner 5f6b30b7c0 This replaces the correct but slow code with a more aggressive scc-finder 
based approach to find globals and call sites that need to be copied.  This
speeds up the BU pass on 176.gcc from 22s back up to 2.3s.  Not as good
as 1.5s, but at least it's correct :)

llvm-svn: 20820
2005-03-24 23:06:02 +00:00

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//===- DataStructure.cpp - Implement the core data structure analysis -----===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the core data structure functionality.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/DataStructure/DSGraphTraits.h"
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Instructions.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Timer.h"
#include <algorithm>
using namespace llvm;
#define COLLAPSE_ARRAYS_AGGRESSIVELY 0
namespace {
Statistic<> NumFolds ("dsa", "Number of nodes completely folded");
Statistic<> NumCallNodesMerged("dsa", "Number of call nodes merged");
Statistic<> NumNodeAllocated ("dsa", "Number of nodes allocated");
Statistic<> NumDNE ("dsa", "Number of nodes removed by reachability");
Statistic<> NumTrivialDNE ("dsa", "Number of nodes trivially removed");
Statistic<> NumTrivialGlobalDNE("dsa", "Number of globals trivially removed");
};
#if 0
#define TIME_REGION(VARNAME, DESC) \
NamedRegionTimer VARNAME(DESC)
#else
#define TIME_REGION(VARNAME, DESC)
#endif
using namespace DS;
/// isForwarding - Return true if this NodeHandle is forwarding to another
/// one.
bool DSNodeHandle::isForwarding() const {
return N && N->isForwarding();
}
DSNode *DSNodeHandle::HandleForwarding() const {
assert(N->isForwarding() && "Can only be invoked if forwarding!");
// Handle node forwarding here!
DSNode *Next = N->ForwardNH.getNode(); // Cause recursive shrinkage
Offset += N->ForwardNH.getOffset();
if (--N->NumReferrers == 0) {
// Removing the last referrer to the node, sever the forwarding link
N->stopForwarding();
}
N = Next;
N->NumReferrers++;
if (N->Size <= Offset) {
assert(N->Size <= 1 && "Forwarded to shrunk but not collapsed node?");
Offset = 0;
}
return N;
}
//===----------------------------------------------------------------------===//
// DSScalarMap Implementation
//===----------------------------------------------------------------------===//
DSNodeHandle &DSScalarMap::AddGlobal(GlobalValue *GV) {
assert(ValueMap.count(GV) == 0 && "GV already exists!");
// If the node doesn't exist, check to see if it's a global that is
// equated to another global in the program.
EquivalenceClasses<GlobalValue*>::iterator ECI = GlobalECs.findValue(GV);
if (ECI != GlobalECs.end()) {
GlobalValue *Leader = *GlobalECs.findLeader(ECI);
if (Leader != GV) {
GV = Leader;
iterator I = ValueMap.find(GV);
if (I != ValueMap.end())
return I->second;
}
}
// Okay, this is either not an equivalenced global or it is the leader, it
// will be inserted into the scalar map now.
GlobalSet.insert(GV);
return ValueMap.insert(std::make_pair(GV, DSNodeHandle())).first->second;
}
//===----------------------------------------------------------------------===//
// DSNode Implementation
//===----------------------------------------------------------------------===//
DSNode::DSNode(const Type *T, DSGraph *G)
: NumReferrers(0), Size(0), ParentGraph(G), Ty(Type::VoidTy), NodeType(0) {
// Add the type entry if it is specified...
if (T) mergeTypeInfo(T, 0);
if (G) G->addNode(this);
++NumNodeAllocated;
}
// DSNode copy constructor... do not copy over the referrers list!
DSNode::DSNode(const DSNode &N, DSGraph *G, bool NullLinks)
: NumReferrers(0), Size(N.Size), ParentGraph(G),
Ty(N.Ty), NodeType(N.NodeType) {
if (!NullLinks) {
Links = N.Links;
Globals = N.Globals;
} else
Links.resize(N.Links.size()); // Create the appropriate number of null links
G->addNode(this);
++NumNodeAllocated;
}
/// getTargetData - Get the target data object used to construct this node.
///
const TargetData &DSNode::getTargetData() const {
return ParentGraph->getTargetData();
}
void DSNode::assertOK() const {
assert((Ty != Type::VoidTy ||
Ty == Type::VoidTy && (Size == 0 ||
(NodeType & DSNode::Array))) &&
"Node not OK!");
assert(ParentGraph && "Node has no parent?");
const DSScalarMap &SM = ParentGraph->getScalarMap();
for (unsigned i = 0, e = Globals.size(); i != e; ++i) {
assert(SM.global_count(Globals[i]));
assert(SM.find(Globals[i])->second.getNode() == this);
}
}
/// forwardNode - Mark this node as being obsolete, and all references to it
/// should be forwarded to the specified node and offset.
///
void DSNode::forwardNode(DSNode *To, unsigned Offset) {
assert(this != To && "Cannot forward a node to itself!");
assert(ForwardNH.isNull() && "Already forwarding from this node!");
if (To->Size <= 1) Offset = 0;
assert((Offset < To->Size || (Offset == To->Size && Offset == 0)) &&
"Forwarded offset is wrong!");
ForwardNH.setTo(To, Offset);
NodeType = DEAD;
Size = 0;
Ty = Type::VoidTy;
// Remove this node from the parent graph's Nodes list.
ParentGraph->unlinkNode(this);
ParentGraph = 0;
}
// addGlobal - Add an entry for a global value to the Globals list. This also
// marks the node with the 'G' flag if it does not already have it.
//
void DSNode::addGlobal(GlobalValue *GV) {
// First, check to make sure this is the leader if the global is in an
// equivalence class.
GV = getParentGraph()->getScalarMap().getLeaderForGlobal(GV);
// Keep the list sorted.
std::vector<GlobalValue*>::iterator I =
std::lower_bound(Globals.begin(), Globals.end(), GV);
if (I == Globals.end() || *I != GV) {
Globals.insert(I, GV);
NodeType |= GlobalNode;
}
}
// removeGlobal - Remove the specified global that is explicitly in the globals
// list.
void DSNode::removeGlobal(GlobalValue *GV) {
std::vector<GlobalValue*>::iterator I =
std::lower_bound(Globals.begin(), Globals.end(), GV);
assert(I != Globals.end() && *I == GV && "Global not in node!");
Globals.erase(I);
}
/// foldNodeCompletely - If we determine that this node has some funny
/// behavior happening to it that we cannot represent, we fold it down to a
/// single, completely pessimistic, node. This node is represented as a
/// single byte with a single TypeEntry of "void".
///
void DSNode::foldNodeCompletely() {
if (isNodeCompletelyFolded()) return; // If this node is already folded...
++NumFolds;
// If this node has a size that is <= 1, we don't need to create a forwarding
// node.
if (getSize() <= 1) {
NodeType |= DSNode::Array;
Ty = Type::VoidTy;
Size = 1;
assert(Links.size() <= 1 && "Size is 1, but has more links?");
Links.resize(1);
} else {
// Create the node we are going to forward to. This is required because
// some referrers may have an offset that is > 0. By forcing them to
// forward, the forwarder has the opportunity to correct the offset.
DSNode *DestNode = new DSNode(0, ParentGraph);
DestNode->NodeType = NodeType|DSNode::Array;
DestNode->Ty = Type::VoidTy;
DestNode->Size = 1;
DestNode->Globals.swap(Globals);
// Start forwarding to the destination node...
forwardNode(DestNode, 0);
if (!Links.empty()) {
DestNode->Links.reserve(1);
DSNodeHandle NH(DestNode);
DestNode->Links.push_back(Links[0]);
// If we have links, merge all of our outgoing links together...
for (unsigned i = Links.size()-1; i != 0; --i)
NH.getNode()->Links[0].mergeWith(Links[i]);
Links.clear();
} else {
DestNode->Links.resize(1);
}
}
}
/// isNodeCompletelyFolded - Return true if this node has been completely
/// folded down to something that can never be expanded, effectively losing
/// all of the field sensitivity that may be present in the node.
///
bool DSNode::isNodeCompletelyFolded() const {
return getSize() == 1 && Ty == Type::VoidTy && isArray();
}
/// addFullGlobalsList - Compute the full set of global values that are
/// represented by this node. Unlike getGlobalsList(), this requires fair
/// amount of work to compute, so don't treat this method call as free.
void DSNode::addFullGlobalsList(std::vector<GlobalValue*> &List) const {
if (globals_begin() == globals_end()) return;
EquivalenceClasses<GlobalValue*> &EC = getParentGraph()->getGlobalECs();
for (globals_iterator I = globals_begin(), E = globals_end(); I != E; ++I) {
EquivalenceClasses<GlobalValue*>::iterator ECI = EC.findValue(*I);
if (ECI == EC.end())
List.push_back(*I);
else
List.insert(List.end(), EC.member_begin(ECI), EC.member_end());
}
}
/// addFullFunctionList - Identical to addFullGlobalsList, but only return the
/// functions in the full list.
void DSNode::addFullFunctionList(std::vector<Function*> &List) const {
if (globals_begin() == globals_end()) return;
EquivalenceClasses<GlobalValue*> &EC = getParentGraph()->getGlobalECs();
for (globals_iterator I = globals_begin(), E = globals_end(); I != E; ++I) {
EquivalenceClasses<GlobalValue*>::iterator ECI = EC.findValue(*I);
if (ECI == EC.end()) {
if (Function *F = dyn_cast<Function>(*I))
List.push_back(F);
} else {
for (EquivalenceClasses<GlobalValue*>::member_iterator MI =
EC.member_begin(ECI), E = EC.member_end(); MI != E; ++MI)
if (Function *F = dyn_cast<Function>(*MI))
List.push_back(F);
}
}
}
namespace {
/// TypeElementWalker Class - Used for implementation of physical subtyping...
///
class TypeElementWalker {
struct StackState {
const Type *Ty;
unsigned Offset;
unsigned Idx;
StackState(const Type *T, unsigned Off = 0)
: Ty(T), Offset(Off), Idx(0) {}
};
std::vector<StackState> Stack;
const TargetData &TD;
public:
TypeElementWalker(const Type *T, const TargetData &td) : TD(td) {
Stack.push_back(T);
StepToLeaf();
}
bool isDone() const { return Stack.empty(); }
const Type *getCurrentType() const { return Stack.back().Ty; }
unsigned getCurrentOffset() const { return Stack.back().Offset; }
void StepToNextType() {
PopStackAndAdvance();
StepToLeaf();
}
private:
/// PopStackAndAdvance - Pop the current element off of the stack and
/// advance the underlying element to the next contained member.
void PopStackAndAdvance() {
assert(!Stack.empty() && "Cannot pop an empty stack!");
Stack.pop_back();
while (!Stack.empty()) {
StackState &SS = Stack.back();
if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
++SS.Idx;
if (SS.Idx != ST->getNumElements()) {
const StructLayout *SL = TD.getStructLayout(ST);
SS.Offset +=
unsigned(SL->MemberOffsets[SS.Idx]-SL->MemberOffsets[SS.Idx-1]);
return;
}
Stack.pop_back(); // At the end of the structure
} else {
const ArrayType *AT = cast<ArrayType>(SS.Ty);
++SS.Idx;
if (SS.Idx != AT->getNumElements()) {
SS.Offset += unsigned(TD.getTypeSize(AT->getElementType()));
return;
}
Stack.pop_back(); // At the end of the array
}
}
}
/// StepToLeaf - Used by physical subtyping to move to the first leaf node
/// on the type stack.
void StepToLeaf() {
if (Stack.empty()) return;
while (!Stack.empty() && !Stack.back().Ty->isFirstClassType()) {
StackState &SS = Stack.back();
if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
if (ST->getNumElements() == 0) {
assert(SS.Idx == 0);
PopStackAndAdvance();
} else {
// Step into the structure...
assert(SS.Idx < ST->getNumElements());
const StructLayout *SL = TD.getStructLayout(ST);
Stack.push_back(StackState(ST->getElementType(SS.Idx),
SS.Offset+unsigned(SL->MemberOffsets[SS.Idx])));
}
} else {
const ArrayType *AT = cast<ArrayType>(SS.Ty);
if (AT->getNumElements() == 0) {
assert(SS.Idx == 0);
PopStackAndAdvance();
} else {
// Step into the array...
assert(SS.Idx < AT->getNumElements());
Stack.push_back(StackState(AT->getElementType(),
SS.Offset+SS.Idx*
unsigned(TD.getTypeSize(AT->getElementType()))));
}
}
}
}
};
} // end anonymous namespace
/// ElementTypesAreCompatible - Check to see if the specified types are
/// "physically" compatible. If so, return true, else return false. We only
/// have to check the fields in T1: T2 may be larger than T1. If AllowLargerT1
/// is true, then we also allow a larger T1.
///
static bool ElementTypesAreCompatible(const Type *T1, const Type *T2,
bool AllowLargerT1, const TargetData &TD){
TypeElementWalker T1W(T1, TD), T2W(T2, TD);
while (!T1W.isDone() && !T2W.isDone()) {
if (T1W.getCurrentOffset() != T2W.getCurrentOffset())
return false;
const Type *T1 = T1W.getCurrentType();
const Type *T2 = T2W.getCurrentType();
if (T1 != T2 && !T1->isLosslesslyConvertibleTo(T2))
return false;
T1W.StepToNextType();
T2W.StepToNextType();
}
return AllowLargerT1 || T1W.isDone();
}
/// mergeTypeInfo - This method merges the specified type into the current node
/// at the specified offset. This may update the current node's type record if
/// this gives more information to the node, it may do nothing to the node if
/// this information is already known, or it may merge the node completely (and
/// return true) if the information is incompatible with what is already known.
///
/// This method returns true if the node is completely folded, otherwise false.
///
bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset,
bool FoldIfIncompatible) {
const TargetData &TD = getTargetData();
// Check to make sure the Size member is up-to-date. Size can be one of the
// following:
// Size = 0, Ty = Void: Nothing is known about this node.
// Size = 0, Ty = FnTy: FunctionPtr doesn't have a size, so we use zero
// Size = 1, Ty = Void, Array = 1: The node is collapsed
// Otherwise, sizeof(Ty) = Size
//
assert(((Size == 0 && Ty == Type::VoidTy && !isArray()) ||
(Size == 0 && !Ty->isSized() && !isArray()) ||
(Size == 1 && Ty == Type::VoidTy && isArray()) ||
(Size == 0 && !Ty->isSized() && !isArray()) ||
(TD.getTypeSize(Ty) == Size)) &&
"Size member of DSNode doesn't match the type structure!");
assert(NewTy != Type::VoidTy && "Cannot merge void type into DSNode!");
if (Offset == 0 && NewTy == Ty)
return false; // This should be a common case, handle it efficiently
// Return true immediately if the node is completely folded.
if (isNodeCompletelyFolded()) return true;
// If this is an array type, eliminate the outside arrays because they won't
// be used anyway. This greatly reduces the size of large static arrays used
// as global variables, for example.
//
bool WillBeArray = false;
while (const ArrayType *AT = dyn_cast<ArrayType>(NewTy)) {
// FIXME: we might want to keep small arrays, but must be careful about
// things like: [2 x [10000 x int*]]
NewTy = AT->getElementType();
WillBeArray = true;
}
// Figure out how big the new type we're merging in is...
unsigned NewTySize = NewTy->isSized() ? (unsigned)TD.getTypeSize(NewTy) : 0;
// Otherwise check to see if we can fold this type into the current node. If
// we can't, we fold the node completely, if we can, we potentially update our
// internal state.
//
if (Ty == Type::VoidTy) {
// If this is the first type that this node has seen, just accept it without
// question....
assert(Offset == 0 && !isArray() &&
"Cannot have an offset into a void node!");
// If this node would have to have an unreasonable number of fields, just
// collapse it. This can occur for fortran common blocks, which have stupid
// things like { [100000000 x double], [1000000 x double] }.
unsigned NumFields = (NewTySize+DS::PointerSize-1) >> DS::PointerShift;
if (NumFields > 256) {
foldNodeCompletely();
return true;
}
Ty = NewTy;
NodeType &= ~Array;
if (WillBeArray) NodeType |= Array;
Size = NewTySize;
// Calculate the number of outgoing links from this node.
Links.resize(NumFields);
return false;
}
// Handle node expansion case here...
if (Offset+NewTySize > Size) {
// It is illegal to grow this node if we have treated it as an array of
// objects...
if (isArray()) {
if (FoldIfIncompatible) foldNodeCompletely();
return true;
}
if (Offset) { // We could handle this case, but we don't for now...
std::cerr << "UNIMP: Trying to merge a growth type into "
<< "offset != 0: Collapsing!\n";
if (FoldIfIncompatible) foldNodeCompletely();
return true;
}
// Okay, the situation is nice and simple, we are trying to merge a type in
// at offset 0 that is bigger than our current type. Implement this by
// switching to the new type and then merge in the smaller one, which should
// hit the other code path here. If the other code path decides it's not
// ok, it will collapse the node as appropriate.
//
// If this node would have to have an unreasonable number of fields, just
// collapse it. This can occur for fortran common blocks, which have stupid
// things like { [100000000 x double], [1000000 x double] }.
unsigned NumFields = (NewTySize+DS::PointerSize-1) >> DS::PointerShift;
if (NumFields > 256) {
foldNodeCompletely();
return true;
}
const Type *OldTy = Ty;
Ty = NewTy;
NodeType &= ~Array;
if (WillBeArray) NodeType |= Array;
Size = NewTySize;
// Must grow links to be the appropriate size...
Links.resize(NumFields);
// Merge in the old type now... which is guaranteed to be smaller than the
// "current" type.
return mergeTypeInfo(OldTy, 0);
}
assert(Offset <= Size &&
"Cannot merge something into a part of our type that doesn't exist!");
// Find the section of Ty that NewTy overlaps with... first we find the
// type that starts at offset Offset.
//
unsigned O = 0;
const Type *SubType = Ty;
while (O < Offset) {
assert(Offset-O < TD.getTypeSize(SubType) && "Offset out of range!");
switch (SubType->getTypeID()) {
case Type::StructTyID: {
const StructType *STy = cast<StructType>(SubType);
const StructLayout &SL = *TD.getStructLayout(STy);
unsigned i = SL.getElementContainingOffset(Offset-O);
// The offset we are looking for must be in the i'th element...
SubType = STy->getElementType(i);
O += (unsigned)SL.MemberOffsets[i];
break;
}
case Type::ArrayTyID: {
SubType = cast<ArrayType>(SubType)->getElementType();
unsigned ElSize = (unsigned)TD.getTypeSize(SubType);
unsigned Remainder = (Offset-O) % ElSize;
O = Offset-Remainder;
break;
}
default:
if (FoldIfIncompatible) foldNodeCompletely();
return true;
}
}
assert(O == Offset && "Could not achieve the correct offset!");
// If we found our type exactly, early exit
if (SubType == NewTy) return false;
// Differing function types don't require us to merge. They are not values
// anyway.
if (isa<FunctionType>(SubType) &&
isa<FunctionType>(NewTy)) return false;
unsigned SubTypeSize = SubType->isSized() ?
(unsigned)TD.getTypeSize(SubType) : 0;
// Ok, we are getting desperate now. Check for physical subtyping, where we
// just require each element in the node to be compatible.
if (NewTySize <= SubTypeSize && NewTySize && NewTySize < 256 &&
SubTypeSize && SubTypeSize < 256 &&
ElementTypesAreCompatible(NewTy, SubType, !isArray(), TD))
return false;
// Okay, so we found the leader type at the offset requested. Search the list
// of types that starts at this offset. If SubType is currently an array or
// structure, the type desired may actually be the first element of the
// composite type...
//
unsigned PadSize = SubTypeSize; // Size, including pad memory which is ignored
while (SubType != NewTy) {
const Type *NextSubType = 0;
unsigned NextSubTypeSize = 0;
unsigned NextPadSize = 0;
switch (SubType->getTypeID()) {
case Type::StructTyID: {
const StructType *STy = cast<StructType>(SubType);
const StructLayout &SL = *TD.getStructLayout(STy);
if (SL.MemberOffsets.size() > 1)
NextPadSize = (unsigned)SL.MemberOffsets[1];
else
NextPadSize = SubTypeSize;
NextSubType = STy->getElementType(0);
NextSubTypeSize = (unsigned)TD.getTypeSize(NextSubType);
break;
}
case Type::ArrayTyID:
NextSubType = cast<ArrayType>(SubType)->getElementType();
NextSubTypeSize = (unsigned)TD.getTypeSize(NextSubType);
NextPadSize = NextSubTypeSize;
break;
default: ;
// fall out
}
if (NextSubType == 0)
break; // In the default case, break out of the loop
if (NextPadSize < NewTySize)
break; // Don't allow shrinking to a smaller type than NewTySize
SubType = NextSubType;
SubTypeSize = NextSubTypeSize;
PadSize = NextPadSize;
}
// If we found the type exactly, return it...
if (SubType == NewTy)
return false;
// Check to see if we have a compatible, but different type...
if (NewTySize == SubTypeSize) {
// Check to see if this type is obviously convertible... int -> uint f.e.
if (NewTy->isLosslesslyConvertibleTo(SubType))
return false;
// Check to see if we have a pointer & integer mismatch going on here,
// loading a pointer as a long, for example.
//
if (SubType->isInteger() && isa<PointerType>(NewTy) ||
NewTy->isInteger() && isa<PointerType>(SubType))
return false;
} else if (NewTySize > SubTypeSize && NewTySize <= PadSize) {
// We are accessing the field, plus some structure padding. Ignore the
// structure padding.
return false;
}
Module *M = 0;
if (getParentGraph()->retnodes_begin() != getParentGraph()->retnodes_end())
M = getParentGraph()->retnodes_begin()->first->getParent();
DEBUG(std::cerr << "MergeTypeInfo Folding OrigTy: ";
WriteTypeSymbolic(std::cerr, Ty, M) << "\n due to:";
WriteTypeSymbolic(std::cerr, NewTy, M) << " @ " << Offset << "!\n"
<< "SubType: ";
WriteTypeSymbolic(std::cerr, SubType, M) << "\n\n");
if (FoldIfIncompatible) foldNodeCompletely();
return true;
}
/// addEdgeTo - Add an edge from the current node to the specified node. This
/// can cause merging of nodes in the graph.
///
void DSNode::addEdgeTo(unsigned Offset, const DSNodeHandle &NH) {
if (NH.isNull()) return; // Nothing to do
DSNodeHandle &ExistingEdge = getLink(Offset);
if (!ExistingEdge.isNull()) {
// Merge the two nodes...
ExistingEdge.mergeWith(NH);
} else { // No merging to perform...
setLink(Offset, NH); // Just force a link in there...
}
}
/// MergeSortedVectors - Efficiently merge a vector into another vector where
/// duplicates are not allowed and both are sorted. This assumes that 'T's are
/// efficiently copyable and have sane comparison semantics.
///
static void MergeSortedVectors(std::vector<GlobalValue*> &Dest,
const std::vector<GlobalValue*> &Src) {
// By far, the most common cases will be the simple ones. In these cases,
// avoid having to allocate a temporary vector...
//
if (Src.empty()) { // Nothing to merge in...
return;
} else if (Dest.empty()) { // Just copy the result in...
Dest = Src;
} else if (Src.size() == 1) { // Insert a single element...
const GlobalValue *V = Src[0];
std::vector<GlobalValue*>::iterator I =
std::lower_bound(Dest.begin(), Dest.end(), V);
if (I == Dest.end() || *I != Src[0]) // If not already contained...
Dest.insert(I, Src[0]);
} else if (Dest.size() == 1) {
GlobalValue *Tmp = Dest[0]; // Save value in temporary...
Dest = Src; // Copy over list...
std::vector<GlobalValue*>::iterator I =
std::lower_bound(Dest.begin(), Dest.end(), Tmp);
if (I == Dest.end() || *I != Tmp) // If not already contained...
Dest.insert(I, Tmp);
} else {
// Make a copy to the side of Dest...
std::vector<GlobalValue*> Old(Dest);
// Make space for all of the type entries now...
Dest.resize(Dest.size()+Src.size());
// Merge the two sorted ranges together... into Dest.
std::merge(Old.begin(), Old.end(), Src.begin(), Src.end(), Dest.begin());
// Now erase any duplicate entries that may have accumulated into the
// vectors (because they were in both of the input sets)
Dest.erase(std::unique(Dest.begin(), Dest.end()), Dest.end());
}
}
void DSNode::mergeGlobals(const std::vector<GlobalValue*> &RHS) {
MergeSortedVectors(Globals, RHS);
}
// MergeNodes - Helper function for DSNode::mergeWith().
// This function does the hard work of merging two nodes, CurNodeH
// and NH after filtering out trivial cases and making sure that
// CurNodeH.offset >= NH.offset.
//
// ***WARNING***
// Since merging may cause either node to go away, we must always
// use the node-handles to refer to the nodes. These node handles are
// automatically updated during merging, so will always provide access
// to the correct node after a merge.
//
void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
assert(CurNodeH.getOffset() >= NH.getOffset() &&
"This should have been enforced in the caller.");
assert(CurNodeH.getNode()->getParentGraph()==NH.getNode()->getParentGraph() &&
"Cannot merge two nodes that are not in the same graph!");
// Now we know that Offset >= NH.Offset, so convert it so our "Offset" (with
// respect to NH.Offset) is now zero. NOffset is the distance from the base
// of our object that N starts from.
//
unsigned NOffset = CurNodeH.getOffset()-NH.getOffset();
unsigned NSize = NH.getNode()->getSize();
// If the two nodes are of different size, and the smaller node has the array
// bit set, collapse!
if (NSize != CurNodeH.getNode()->getSize()) {
#if COLLAPSE_ARRAYS_AGGRESSIVELY
if (NSize < CurNodeH.getNode()->getSize()) {
if (NH.getNode()->isArray())
NH.getNode()->foldNodeCompletely();
} else if (CurNodeH.getNode()->isArray()) {
NH.getNode()->foldNodeCompletely();
}
#endif
}
// Merge the type entries of the two nodes together...
if (NH.getNode()->Ty != Type::VoidTy)
CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
assert(!CurNodeH.getNode()->isDeadNode());
// If we are merging a node with a completely folded node, then both nodes are
// now completely folded.
//
if (CurNodeH.getNode()->isNodeCompletelyFolded()) {
if (!NH.getNode()->isNodeCompletelyFolded()) {
NH.getNode()->foldNodeCompletely();
assert(NH.getNode() && NH.getOffset() == 0 &&
"folding did not make offset 0?");
NOffset = NH.getOffset();
NSize = NH.getNode()->getSize();
assert(NOffset == 0 && NSize == 1);
}
} else if (NH.getNode()->isNodeCompletelyFolded()) {
CurNodeH.getNode()->foldNodeCompletely();
assert(CurNodeH.getNode() && CurNodeH.getOffset() == 0 &&
"folding did not make offset 0?");
NSize = NH.getNode()->getSize();
NOffset = NH.getOffset();
assert(NOffset == 0 && NSize == 1);
}
DSNode *N = NH.getNode();
if (CurNodeH.getNode() == N || N == 0) return;
assert(!CurNodeH.getNode()->isDeadNode());
// Merge the NodeType information.
CurNodeH.getNode()->NodeType |= N->NodeType;
// Start forwarding to the new node!
N->forwardNode(CurNodeH.getNode(), NOffset);
assert(!CurNodeH.getNode()->isDeadNode());
// Make all of the outgoing links of N now be outgoing links of CurNodeH.
//
for (unsigned i = 0; i < N->getNumLinks(); ++i) {
DSNodeHandle &Link = N->getLink(i << DS::PointerShift);
if (Link.getNode()) {
// Compute the offset into the current node at which to
// merge this link. In the common case, this is a linear
// relation to the offset in the original node (with
// wrapping), but if the current node gets collapsed due to
// recursive merging, we must make sure to merge in all remaining
// links at offset zero.
unsigned MergeOffset = 0;
DSNode *CN = CurNodeH.getNode();
if (CN->Size != 1)
MergeOffset = ((i << DS::PointerShift)+NOffset) % CN->getSize();
CN->addEdgeTo(MergeOffset, Link);
}
}
// Now that there are no outgoing edges, all of the Links are dead.
N->Links.clear();
// Merge the globals list...
if (!N->Globals.empty()) {
CurNodeH.getNode()->mergeGlobals(N->Globals);
// Delete the globals from the old node...
std::vector<GlobalValue*>().swap(N->Globals);
}
}
/// mergeWith - Merge this node and the specified node, moving all links to and
/// from the argument node into the current node, deleting the node argument.
/// Offset indicates what offset the specified node is to be merged into the
/// current node.
///
/// The specified node may be a null pointer (in which case, we update it to
/// point to this node).
///
void DSNode::mergeWith(const DSNodeHandle &NH, unsigned Offset) {
DSNode *N = NH.getNode();
if (N == this && NH.getOffset() == Offset)
return; // Noop
// If the RHS is a null node, make it point to this node!
if (N == 0) {
NH.mergeWith(DSNodeHandle(this, Offset));
return;
}
assert(!N->isDeadNode() && !isDeadNode());
assert(!hasNoReferrers() && "Should not try to fold a useless node!");
if (N == this) {
// We cannot merge two pieces of the same node together, collapse the node
// completely.
DEBUG(std::cerr << "Attempting to merge two chunks of"
<< " the same node together!\n");
foldNodeCompletely();
return;
}
// If both nodes are not at offset 0, make sure that we are merging the node
// at an later offset into the node with the zero offset.
//
if (Offset < NH.getOffset()) {
N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
return;
} else if (Offset == NH.getOffset() && getSize() < N->getSize()) {
// If the offsets are the same, merge the smaller node into the bigger node
N->mergeWith(DSNodeHandle(this, Offset), NH.getOffset());
return;
}
// Ok, now we can merge the two nodes. Use a static helper that works with
// two node handles, since "this" may get merged away at intermediate steps.
DSNodeHandle CurNodeH(this, Offset);
DSNodeHandle NHCopy(NH);
DSNode::MergeNodes(CurNodeH, NHCopy);
}
//===----------------------------------------------------------------------===//
// ReachabilityCloner Implementation
//===----------------------------------------------------------------------===//
DSNodeHandle ReachabilityCloner::getClonedNH(const DSNodeHandle &SrcNH) {
if (SrcNH.isNull()) return DSNodeHandle();
const DSNode *SN = SrcNH.getNode();
DSNodeHandle &NH = NodeMap[SN];
if (!NH.isNull()) { // Node already mapped?
DSNode *NHN = NH.getNode();
return DSNodeHandle(NHN, NH.getOffset()+SrcNH.getOffset());
}
// If SrcNH has globals and the destination graph has one of the same globals,
// merge this node with the destination node, which is much more efficient.
if (SN->globals_begin() != SN->globals_end()) {
DSScalarMap &DestSM = Dest.getScalarMap();
for (DSNode::globals_iterator I = SN->globals_begin(),E = SN->globals_end();
I != E; ++I) {
GlobalValue *GV = *I;
DSScalarMap::iterator GI = DestSM.find(GV);
if (GI != DestSM.end() && !GI->second.isNull()) {
// We found one, use merge instead!
merge(GI->second, Src.getNodeForValue(GV));
assert(!NH.isNull() && "Didn't merge node!");
DSNode *NHN = NH.getNode();
return DSNodeHandle(NHN, NH.getOffset()+SrcNH.getOffset());
}
}
}
DSNode *DN = new DSNode(*SN, &Dest, true /* Null out all links */);
DN->maskNodeTypes(BitsToKeep);
NH = DN;
// Next, recursively clone all outgoing links as necessary. Note that
// adding these links can cause the node to collapse itself at any time, and
// the current node may be merged with arbitrary other nodes. For this
// reason, we must always go through NH.
DN = 0;
for (unsigned i = 0, e = SN->getNumLinks(); i != e; ++i) {
const DSNodeHandle &SrcEdge = SN->getLink(i << DS::PointerShift);
if (!SrcEdge.isNull()) {
const DSNodeHandle &DestEdge = getClonedNH(SrcEdge);
// Compute the offset into the current node at which to
// merge this link. In the common case, this is a linear
// relation to the offset in the original node (with
// wrapping), but if the current node gets collapsed due to
// recursive merging, we must make sure to merge in all remaining
// links at offset zero.
unsigned MergeOffset = 0;
DSNode *CN = NH.getNode();
if (CN->getSize() != 1)
MergeOffset = ((i << DS::PointerShift)+NH.getOffset()) % CN->getSize();
CN->addEdgeTo(MergeOffset, DestEdge);
}
}
// If this node contains any globals, make sure they end up in the scalar
// map with the correct offset.
for (DSNode::globals_iterator I = SN->globals_begin(), E = SN->globals_end();
I != E; ++I) {
GlobalValue *GV = *I;
const DSNodeHandle &SrcGNH = Src.getNodeForValue(GV);
DSNodeHandle &DestGNH = NodeMap[SrcGNH.getNode()];
assert(DestGNH.getNode() == NH.getNode() &&"Global mapping inconsistent");
Dest.getNodeForValue(GV).mergeWith(DSNodeHandle(DestGNH.getNode(),
DestGNH.getOffset()+SrcGNH.getOffset()));
}
NH.getNode()->mergeGlobals(SN->getGlobalsList());
return DSNodeHandle(NH.getNode(), NH.getOffset()+SrcNH.getOffset());
}
void ReachabilityCloner::merge(const DSNodeHandle &NH,
const DSNodeHandle &SrcNH) {
if (SrcNH.isNull()) return; // Noop
if (NH.isNull()) {
// If there is no destination node, just clone the source and assign the
// destination node to be it.
NH.mergeWith(getClonedNH(SrcNH));
return;
}
// Okay, at this point, we know that we have both a destination and a source
// node that need to be merged. Check to see if the source node has already
// been cloned.
const DSNode *SN = SrcNH.getNode();
DSNodeHandle &SCNH = NodeMap[SN]; // SourceClonedNodeHandle
if (!SCNH.isNull()) { // Node already cloned?
DSNode *SCNHN = SCNH.getNode();
NH.mergeWith(DSNodeHandle(SCNHN,
SCNH.getOffset()+SrcNH.getOffset()));
return; // Nothing to do!
}
// Okay, so the source node has not already been cloned. Instead of creating
// a new DSNode, only to merge it into the one we already have, try to perform
// the merge in-place. The only case we cannot handle here is when the offset
// into the existing node is less than the offset into the virtual node we are
// merging in. In this case, we have to extend the existing node, which
// requires an allocation anyway.
DSNode *DN = NH.getNode(); // Make sure the Offset is up-to-date
if (NH.getOffset() >= SrcNH.getOffset()) {
if (!DN->isNodeCompletelyFolded()) {
// Make sure the destination node is folded if the source node is folded.
if (SN->isNodeCompletelyFolded()) {
DN->foldNodeCompletely();
DN = NH.getNode();
} else if (SN->getSize() != DN->getSize()) {
// If the two nodes are of different size, and the smaller node has the
// array bit set, collapse!
#if COLLAPSE_ARRAYS_AGGRESSIVELY
if (SN->getSize() < DN->getSize()) {
if (SN->isArray()) {
DN->foldNodeCompletely();
DN = NH.getNode();
}
} else if (DN->isArray()) {
DN->foldNodeCompletely();
DN = NH.getNode();
}
#endif
}
// Merge the type entries of the two nodes together...
if (SN->getType() != Type::VoidTy && !DN->isNodeCompletelyFolded()) {
DN->mergeTypeInfo(SN->getType(), NH.getOffset()-SrcNH.getOffset());
DN = NH.getNode();
}
}
assert(!DN->isDeadNode());
// Merge the NodeType information.
DN->mergeNodeFlags(SN->getNodeFlags() & BitsToKeep);
// Before we start merging outgoing links and updating the scalar map, make
// sure it is known that this is the representative node for the src node.
SCNH = DSNodeHandle(DN, NH.getOffset()-SrcNH.getOffset());
// If the source node contains any globals, make sure they end up in the
// scalar map with the correct offset.
if (SN->globals_begin() != SN->globals_end()) {
// Update the globals in the destination node itself.
DN->mergeGlobals(SN->getGlobalsList());
// Update the scalar map for the graph we are merging the source node
// into.
for (DSNode::globals_iterator I = SN->globals_begin(),
E = SN->globals_end(); I != E; ++I) {
GlobalValue *GV = *I;
const DSNodeHandle &SrcGNH = Src.getNodeForValue(GV);
DSNodeHandle &DestGNH = NodeMap[SrcGNH.getNode()];
assert(DestGNH.getNode()==NH.getNode() &&"Global mapping inconsistent");
Dest.getNodeForValue(GV).mergeWith(DSNodeHandle(DestGNH.getNode(),
DestGNH.getOffset()+SrcGNH.getOffset()));
}
NH.getNode()->mergeGlobals(SN->getGlobalsList());
}
} else {
// We cannot handle this case without allocating a temporary node. Fall
// back on being simple.
DSNode *NewDN = new DSNode(*SN, &Dest, true /* Null out all links */);
NewDN->maskNodeTypes(BitsToKeep);
unsigned NHOffset = NH.getOffset();
NH.mergeWith(DSNodeHandle(NewDN, SrcNH.getOffset()));
assert(NH.getNode() &&
(NH.getOffset() > NHOffset ||
(NH.getOffset() == 0 && NH.getNode()->isNodeCompletelyFolded())) &&
"Merging did not adjust the offset!");
// Before we start merging outgoing links and updating the scalar map, make
// sure it is known that this is the representative node for the src node.
SCNH = DSNodeHandle(NH.getNode(), NH.getOffset()-SrcNH.getOffset());
// If the source node contained any globals, make sure to create entries
// in the scalar map for them!
for (DSNode::globals_iterator I = SN->globals_begin(),
E = SN->globals_end(); I != E; ++I) {
GlobalValue *GV = *I;
const DSNodeHandle &SrcGNH = Src.getNodeForValue(GV);
DSNodeHandle &DestGNH = NodeMap[SrcGNH.getNode()];
assert(DestGNH.getNode()==NH.getNode() &&"Global mapping inconsistent");
assert(SrcGNH.getNode() == SN && "Global mapping inconsistent");
Dest.getNodeForValue(GV).mergeWith(DSNodeHandle(DestGNH.getNode(),
DestGNH.getOffset()+SrcGNH.getOffset()));
}
}
// Next, recursively merge all outgoing links as necessary. Note that
// adding these links can cause the destination node to collapse itself at
// any time, and the current node may be merged with arbitrary other nodes.
// For this reason, we must always go through NH.
DN = 0;
for (unsigned i = 0, e = SN->getNumLinks(); i != e; ++i) {
const DSNodeHandle &SrcEdge = SN->getLink(i << DS::PointerShift);
if (!SrcEdge.isNull()) {
// Compute the offset into the current node at which to
// merge this link. In the common case, this is a linear
// relation to the offset in the original node (with
// wrapping), but if the current node gets collapsed due to
// recursive merging, we must make sure to merge in all remaining
// links at offset zero.
DSNode *CN = SCNH.getNode();
unsigned MergeOffset =
((i << DS::PointerShift)+SCNH.getOffset()) % CN->getSize();
DSNodeHandle Tmp = CN->getLink(MergeOffset);
if (!Tmp.isNull()) {
// Perform the recursive merging. Make sure to create a temporary NH,
// because the Link can disappear in the process of recursive merging.
merge(Tmp, SrcEdge);
} else {
Tmp.mergeWith(getClonedNH(SrcEdge));
// Merging this could cause all kinds of recursive things to happen,
// culminating in the current node being eliminated. Since this is
// possible, make sure to reaquire the link from 'CN'.
unsigned MergeOffset = 0;
CN = SCNH.getNode();
MergeOffset = ((i << DS::PointerShift)+SCNH.getOffset()) %CN->getSize();
CN->getLink(MergeOffset).mergeWith(Tmp);
}
}
}
}
/// mergeCallSite - Merge the nodes reachable from the specified src call
/// site into the nodes reachable from DestCS.
void ReachabilityCloner::mergeCallSite(DSCallSite &DestCS,
const DSCallSite &SrcCS) {
merge(DestCS.getRetVal(), SrcCS.getRetVal());
unsigned MinArgs = DestCS.getNumPtrArgs();
if (SrcCS.getNumPtrArgs() < MinArgs) MinArgs = SrcCS.getNumPtrArgs();
for (unsigned a = 0; a != MinArgs; ++a)
merge(DestCS.getPtrArg(a), SrcCS.getPtrArg(a));
for (unsigned a = MinArgs, e = SrcCS.getNumPtrArgs(); a != e; ++a)
DestCS.addPtrArg(getClonedNH(SrcCS.getPtrArg(a)));
}
//===----------------------------------------------------------------------===//
// DSCallSite Implementation
//===----------------------------------------------------------------------===//
// Define here to avoid including iOther.h and BasicBlock.h in DSGraph.h
Function &DSCallSite::getCaller() const {
return *Site.getInstruction()->getParent()->getParent();
}
void DSCallSite::InitNH(DSNodeHandle &NH, const DSNodeHandle &Src,
ReachabilityCloner &RC) {
NH = RC.getClonedNH(Src);
}
//===----------------------------------------------------------------------===//
// DSGraph Implementation
//===----------------------------------------------------------------------===//
/// getFunctionNames - Return a space separated list of the name of the
/// functions in this graph (if any)
std::string DSGraph::getFunctionNames() const {
switch (getReturnNodes().size()) {
case 0: return "Globals graph";
case 1: return retnodes_begin()->first->getName();
default:
std::string Return;
for (DSGraph::retnodes_iterator I = retnodes_begin();
I != retnodes_end(); ++I)
Return += I->first->getName() + " ";
Return.erase(Return.end()-1, Return.end()); // Remove last space character
return Return;
}
}
DSGraph::DSGraph(const DSGraph &G, EquivalenceClasses<GlobalValue*> &ECs,
unsigned CloneFlags)
: GlobalsGraph(0), ScalarMap(ECs), TD(G.TD) {
PrintAuxCalls = false;
cloneInto(G, CloneFlags);
}
DSGraph::~DSGraph() {
FunctionCalls.clear();
AuxFunctionCalls.clear();
ScalarMap.clear();
ReturnNodes.clear();
// Drop all intra-node references, so that assertions don't fail...
for (node_iterator NI = node_begin(), E = node_end(); NI != E; ++NI)
NI->dropAllReferences();
// Free all of the nodes.
Nodes.clear();
}
// dump - Allow inspection of graph in a debugger.
void DSGraph::dump() const { print(std::cerr); }
/// remapLinks - Change all of the Links in the current node according to the
/// specified mapping.
///
void DSNode::remapLinks(DSGraph::NodeMapTy &OldNodeMap) {
for (unsigned i = 0, e = Links.size(); i != e; ++i)
if (DSNode *N = Links[i].getNode()) {
DSGraph::NodeMapTy::const_iterator ONMI = OldNodeMap.find(N);
if (ONMI != OldNodeMap.end()) {
DSNode *ONMIN = ONMI->second.getNode();
Links[i].setTo(ONMIN, Links[i].getOffset()+ONMI->second.getOffset());
}
}
}
/// addObjectToGraph - This method can be used to add global, stack, and heap
/// objects to the graph. This can be used when updating DSGraphs due to the
/// introduction of new temporary objects. The new object is not pointed to
/// and does not point to any other objects in the graph.
DSNode *DSGraph::addObjectToGraph(Value *Ptr, bool UseDeclaredType) {
assert(isa<PointerType>(Ptr->getType()) && "Ptr is not a pointer!");
const Type *Ty = cast<PointerType>(Ptr->getType())->getElementType();
DSNode *N = new DSNode(UseDeclaredType ? Ty : 0, this);
assert(ScalarMap[Ptr].isNull() && "Object already in this graph!");
ScalarMap[Ptr] = N;
if (GlobalValue *GV = dyn_cast<GlobalValue>(Ptr)) {
N->addGlobal(GV);
} else if (MallocInst *MI = dyn_cast<MallocInst>(Ptr)) {
N->setHeapNodeMarker();
} else if (AllocaInst *AI = dyn_cast<AllocaInst>(Ptr)) {
N->setAllocaNodeMarker();
} else {
assert(0 && "Illegal memory object input!");
}
return N;
}
/// cloneInto - Clone the specified DSGraph into the current graph. The
/// translated ScalarMap for the old function is filled into the ScalarMap
/// for the graph, and the translated ReturnNodes map is returned into
/// ReturnNodes.
///
/// The CloneFlags member controls various aspects of the cloning process.
///
void DSGraph::cloneInto(const DSGraph &G, unsigned CloneFlags) {
TIME_REGION(X, "cloneInto");
assert(&G != this && "Cannot clone graph into itself!");
NodeMapTy OldNodeMap;
// Remove alloca or mod/ref bits as specified...
unsigned BitsToClear = ((CloneFlags & StripAllocaBit)? DSNode::AllocaNode : 0)
| ((CloneFlags & StripModRefBits)? (DSNode::Modified | DSNode::Read) : 0)
| ((CloneFlags & StripIncompleteBit)? DSNode::Incomplete : 0);
BitsToClear |= DSNode::DEAD; // Clear dead flag...
for (node_const_iterator I = G.node_begin(), E = G.node_end(); I != E; ++I) {
assert(!I->isForwarding() &&
"Forward nodes shouldn't be in node list!");
DSNode *New = new DSNode(*I, this);
New->maskNodeTypes(~BitsToClear);
OldNodeMap[I] = New;
}
#ifndef NDEBUG
Timer::addPeakMemoryMeasurement();
#endif
// Rewrite the links in the new nodes to point into the current graph now.
// Note that we don't loop over the node's list to do this. The problem is
// that remaping links can cause recursive merging to happen, which means
// that node_iterator's can get easily invalidated! Because of this, we
// loop over the OldNodeMap, which contains all of the new nodes as the
// .second element of the map elements. Also note that if we remap a node
// more than once, we won't break anything.
for (NodeMapTy::iterator I = OldNodeMap.begin(), E = OldNodeMap.end();
I != E; ++I)
I->second.getNode()->remapLinks(OldNodeMap);
// Copy the scalar map... merging all of the global nodes...
for (DSScalarMap::const_iterator I = G.ScalarMap.begin(),
E = G.ScalarMap.end(); I != E; ++I) {
DSNodeHandle &MappedNode = OldNodeMap[I->second.getNode()];
DSNodeHandle &H = ScalarMap.getRawEntryRef(I->first);
DSNode *MappedNodeN = MappedNode.getNode();
H.mergeWith(DSNodeHandle(MappedNodeN,
I->second.getOffset()+MappedNode.getOffset()));
}
if (!(CloneFlags & DontCloneCallNodes)) {
// Copy the function calls list.
for (fc_iterator I = G.fc_begin(), E = G.fc_end(); I != E; ++I)
FunctionCalls.push_back(DSCallSite(*I, OldNodeMap));
}
if (!(CloneFlags & DontCloneAuxCallNodes)) {
// Copy the auxiliary function calls list.
for (afc_iterator I = G.afc_begin(), E = G.afc_end(); I != E; ++I)
AuxFunctionCalls.push_back(DSCallSite(*I, OldNodeMap));
}
// Map the return node pointers over...
for (retnodes_iterator I = G.retnodes_begin(),
E = G.retnodes_end(); I != E; ++I) {
const DSNodeHandle &Ret = I->second;
DSNodeHandle &MappedRet = OldNodeMap[Ret.getNode()];
DSNode *MappedRetN = MappedRet.getNode();
ReturnNodes.insert(std::make_pair(I->first,
DSNodeHandle(MappedRetN,
MappedRet.getOffset()+Ret.getOffset())));
}
}
/// getFunctionArgumentsForCall - Given a function that is currently in this
/// graph, return the DSNodeHandles that correspond to the pointer-compatible
/// function arguments. The vector is filled in with the return value (or
/// null if it is not pointer compatible), followed by all of the
/// pointer-compatible arguments.
void DSGraph::getFunctionArgumentsForCall(Function *F,
std::vector<DSNodeHandle> &Args) const {
Args.push_back(getReturnNodeFor(*F));
for (Function::arg_iterator AI = F->arg_begin(), E = F->arg_end();
AI != E; ++AI)
if (isPointerType(AI->getType())) {
Args.push_back(getNodeForValue(AI));
assert(!Args.back().isNull() && "Pointer argument w/o scalarmap entry!?");
}
}
namespace {
// HackedGraphSCCFinder - This is used to find nodes that have a path from the
// node to a node cloned by the ReachabilityCloner object contained. To be
// extra obnoxious it ignores edges from nodes that are globals, and truncates
// search at RC marked nodes. This is designed as an object so that
// intermediate results can be memoized across invocations of
// PathExistsToClonedNode.
struct HackedGraphSCCFinder {
ReachabilityCloner &RC;
unsigned CurNodeId;
std::vector<const DSNode*> SCCStack;
std::map<const DSNode*, std::pair<unsigned, bool> > NodeInfo;
HackedGraphSCCFinder(ReachabilityCloner &rc) : RC(rc), CurNodeId(1) {
// Remove null pointer as a special case.
NodeInfo[0] = std::make_pair(0, false);
}
std::pair<unsigned, bool> &VisitForSCCs(const DSNode *N);
bool PathExistsToClonedNode(const DSNode *N) {
return VisitForSCCs(N).second;
}
bool PathExistsToClonedNode(const DSCallSite &CS) {
if (PathExistsToClonedNode(CS.getRetVal().getNode()))
return true;
for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i)
if (PathExistsToClonedNode(CS.getPtrArg(i).getNode()))
return true;
return false;
}
};
}
std::pair<unsigned, bool> &HackedGraphSCCFinder::
VisitForSCCs(const DSNode *N) {
std::map<const DSNode*, std::pair<unsigned, bool> >::iterator
NodeInfoIt = NodeInfo.lower_bound(N);
if (NodeInfoIt != NodeInfo.end() && NodeInfoIt->first == N)
return NodeInfoIt->second;
unsigned Min = CurNodeId++;
unsigned MyId = Min;
std::pair<unsigned, bool> &ThisNodeInfo =
NodeInfo.insert(NodeInfoIt,
std::make_pair(N, std::make_pair(MyId, false)))->second;
// Base case: if we find a global, this doesn't reach the cloned graph
// portion.
if (N->isGlobalNode()) {
ThisNodeInfo.second = false;
return ThisNodeInfo;
}
// Base case: if this does reach the cloned graph portion... it does. :)
if (RC.hasClonedNode(N)) {
ThisNodeInfo.second = true;
return ThisNodeInfo;
}
SCCStack.push_back(N);
// Otherwise, check all successors.
bool AnyDirectSuccessorsReachClonedNodes = false;
for (DSNode::const_edge_iterator EI = N->edge_begin(), EE = N->edge_end();
EI != EE; ++EI) {
std::pair<unsigned, bool> &SuccInfo = VisitForSCCs(EI->getNode());
if (SuccInfo.first < Min) Min = SuccInfo.first;
AnyDirectSuccessorsReachClonedNodes |= SuccInfo.second;
}
if (Min != MyId)
return ThisNodeInfo; // Part of a large SCC. Leave self on stack.
if (SCCStack.back() == N) { // Special case single node SCC.
SCCStack.pop_back();
ThisNodeInfo.second = AnyDirectSuccessorsReachClonedNodes;
return ThisNodeInfo;
}
// Find out if any direct successors of any node reach cloned nodes.
if (!AnyDirectSuccessorsReachClonedNodes)
for (unsigned i = SCCStack.size()-1; SCCStack[i] != N; --i)
for (DSNode::const_edge_iterator EI = N->edge_begin(), EE = N->edge_end();
EI != EE; ++EI)
if (DSNode *N = EI->getNode())
if (NodeInfo[N].second) {
AnyDirectSuccessorsReachClonedNodes = true;
goto OutOfLoop;
}
OutOfLoop:
// If any successor reaches a cloned node, mark all nodes in this SCC as
// reaching the cloned node.
if (AnyDirectSuccessorsReachClonedNodes)
while (SCCStack.back() != N) {
NodeInfo[SCCStack.back()].second = true;
SCCStack.pop_back();
}
SCCStack.pop_back();
ThisNodeInfo.second = true;
return ThisNodeInfo;
}
/// mergeInCallFromOtherGraph - This graph merges in the minimal number of
/// nodes from G2 into 'this' graph, merging the bindings specified by the
/// call site (in this graph) with the bindings specified by the vector in G2.
/// The two DSGraphs must be different.
///
void DSGraph::mergeInGraph(const DSCallSite &CS,
std::vector<DSNodeHandle> &Args,
const DSGraph &Graph, unsigned CloneFlags) {
TIME_REGION(X, "mergeInGraph");
assert((CloneFlags & DontCloneCallNodes) &&
"Doesn't support copying of call nodes!");
// If this is not a recursive call, clone the graph into this graph...
if (&Graph == this) {
// Merge the return value with the return value of the context.
Args[0].mergeWith(CS.getRetVal());
// Resolve all of the function arguments.
for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i) {
if (i == Args.size()-1)
break;
// Add the link from the argument scalar to the provided value.
Args[i+1].mergeWith(CS.getPtrArg(i));
}
return;
}
// Clone the callee's graph into the current graph, keeping track of where
// scalars in the old graph _used_ to point, and of the new nodes matching
// nodes of the old graph.
ReachabilityCloner RC(*this, Graph, CloneFlags);
// Map the return node pointer over.
if (!CS.getRetVal().isNull())
RC.merge(CS.getRetVal(), Args[0]);
// Map over all of the arguments.
for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i) {
if (i == Args.size()-1)
break;
// Add the link from the argument scalar to the provided value.
RC.merge(CS.getPtrArg(i), Args[i+1]);
}
// We generally don't want to copy global nodes or aux calls from the callee
// graph to the caller graph. However, we have to copy them if there is a
// path from the node to a node we have already copied which does not go
// through another global. Compute the set of node that can reach globals and
// aux call nodes to copy over, then do it.
std::vector<const DSCallSite*> AuxCallToCopy;
std::vector<GlobalValue*> GlobalsToCopy;
// NodesReachCopiedNodes - Memoize results for efficiency. Contains a
// true/false value for every visited node that reaches a copied node without
// going through a global.
HackedGraphSCCFinder SCCFinder(RC);
if (!(CloneFlags & DontCloneAuxCallNodes))
for (afc_iterator I = Graph.afc_begin(), E = Graph.afc_end(); I!=E; ++I)
if (SCCFinder.PathExistsToClonedNode(*I))
AuxCallToCopy.push_back(&*I);
const DSScalarMap &GSM = Graph.getScalarMap();
for (DSScalarMap::global_iterator GI = GSM.global_begin(),
E = GSM.global_end(); GI != E; ++GI) {
DSNode *GlobalNode = Graph.getNodeForValue(*GI).getNode();
for (DSNode::edge_iterator EI = GlobalNode->edge_begin(),
EE = GlobalNode->edge_end(); EI != EE; ++EI)
if (SCCFinder.PathExistsToClonedNode(EI->getNode())) {
GlobalsToCopy.push_back(*GI);
break;
}
}
// Copy aux calls that are needed.
for (unsigned i = 0, e = AuxCallToCopy.size(); i != e; ++i)
AuxFunctionCalls.push_back(DSCallSite(*AuxCallToCopy[i], RC));
// Copy globals that are needed.
for (unsigned i = 0, e = GlobalsToCopy.size(); i != e; ++i)
RC.getClonedNH(Graph.getNodeForValue(GlobalsToCopy[i]));
}
/// mergeInGraph - The method is used for merging graphs together. If the
/// argument graph is not *this, it makes a clone of the specified graph, then
/// merges the nodes specified in the call site with the formal arguments in the
/// graph.
///
void DSGraph::mergeInGraph(const DSCallSite &CS, Function &F,
const DSGraph &Graph, unsigned CloneFlags) {
// Set up argument bindings.
std::vector<DSNodeHandle> Args;
Graph.getFunctionArgumentsForCall(&F, Args);
mergeInGraph(CS, Args, Graph, CloneFlags);
}
/// getCallSiteForArguments - Get the arguments and return value bindings for
/// the specified function in the current graph.
///
DSCallSite DSGraph::getCallSiteForArguments(Function &F) const {
std::vector<DSNodeHandle> Args;
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
if (isPointerType(I->getType()))
Args.push_back(getNodeForValue(I));
return DSCallSite(CallSite(), getReturnNodeFor(F), &F, Args);
}
/// getDSCallSiteForCallSite - Given an LLVM CallSite object that is live in
/// the context of this graph, return the DSCallSite for it.
DSCallSite DSGraph::getDSCallSiteForCallSite(CallSite CS) const {
DSNodeHandle RetVal;
Instruction *I = CS.getInstruction();
if (isPointerType(I->getType()))
RetVal = getNodeForValue(I);
std::vector<DSNodeHandle> Args;
Args.reserve(CS.arg_end()-CS.arg_begin());
// Calculate the arguments vector...
for (CallSite::arg_iterator I = CS.arg_begin(), E = CS.arg_end(); I != E; ++I)
if (isPointerType((*I)->getType()))
if (isa<ConstantPointerNull>(*I))
Args.push_back(DSNodeHandle());
else
Args.push_back(getNodeForValue(*I));
// Add a new function call entry...
if (Function *F = CS.getCalledFunction())
return DSCallSite(CS, RetVal, F, Args);
else
return DSCallSite(CS, RetVal,
getNodeForValue(CS.getCalledValue()).getNode(), Args);
}
// markIncompleteNodes - Mark the specified node as having contents that are not
// known with the current analysis we have performed. Because a node makes all
// of the nodes it can reach incomplete if the node itself is incomplete, we
// must recursively traverse the data structure graph, marking all reachable
// nodes as incomplete.
//
static void markIncompleteNode(DSNode *N) {
// Stop recursion if no node, or if node already marked...
if (N == 0 || N->isIncomplete()) return;
// Actually mark the node
N->setIncompleteMarker();
// Recursively process children...
for (DSNode::edge_iterator I = N->edge_begin(),E = N->edge_end(); I != E; ++I)
if (DSNode *DSN = I->getNode())
markIncompleteNode(DSN);
}
static void markIncomplete(DSCallSite &Call) {
// Then the return value is certainly incomplete!
markIncompleteNode(Call.getRetVal().getNode());
// All objects pointed to by function arguments are incomplete!
for (unsigned i = 0, e = Call.getNumPtrArgs(); i != e; ++i)
markIncompleteNode(Call.getPtrArg(i).getNode());
}
// markIncompleteNodes - Traverse the graph, identifying nodes that may be
// modified by other functions that have not been resolved yet. This marks
// nodes that are reachable through three sources of "unknownness":
//
// Global Variables, Function Calls, and Incoming Arguments
//
// For any node that may have unknown components (because something outside the
// scope of current analysis may have modified it), the 'Incomplete' flag is
// added to the NodeType.
//
void DSGraph::markIncompleteNodes(unsigned Flags) {
// Mark any incoming arguments as incomplete.
if (Flags & DSGraph::MarkFormalArgs)
for (ReturnNodesTy::iterator FI = ReturnNodes.begin(), E =ReturnNodes.end();
FI != E; ++FI) {
Function &F = *FI->first;
for (Function::arg_iterator I = F.arg_begin(), E = F.arg_end(); I != E; ++I)
if (isPointerType(I->getType()))
markIncompleteNode(getNodeForValue(I).getNode());
markIncompleteNode(FI->second.getNode());
}
// Mark stuff passed into functions calls as being incomplete.
if (!shouldPrintAuxCalls())
for (std::list<DSCallSite>::iterator I = FunctionCalls.begin(),
E = FunctionCalls.end(); I != E; ++I)
markIncomplete(*I);
else
for (std::list<DSCallSite>::iterator I = AuxFunctionCalls.begin(),
E = AuxFunctionCalls.end(); I != E; ++I)
markIncomplete(*I);
// Mark all global nodes as incomplete.
for (DSScalarMap::global_iterator I = ScalarMap.global_begin(),
E = ScalarMap.global_end(); I != E; ++I)
if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*I))
if (!GV->hasInitializer() || // Always mark external globals incomp.
(!GV->isConstant() && (Flags & DSGraph::IgnoreGlobals) == 0))
markIncompleteNode(ScalarMap[GV].getNode());
}
static inline void killIfUselessEdge(DSNodeHandle &Edge) {
if (DSNode *N = Edge.getNode()) // Is there an edge?
if (N->getNumReferrers() == 1) // Does it point to a lonely node?
// No interesting info?
if ((N->getNodeFlags() & ~DSNode::Incomplete) == 0 &&
N->getType() == Type::VoidTy && !N->isNodeCompletelyFolded())
Edge.setTo(0, 0); // Kill the edge!
}
static inline bool nodeContainsExternalFunction(const DSNode *N) {
std::vector<Function*> Funcs;
N->addFullFunctionList(Funcs);
for (unsigned i = 0, e = Funcs.size(); i != e; ++i)
if (Funcs[i]->isExternal()) return true;
return false;
}
static void removeIdenticalCalls(std::list<DSCallSite> &Calls) {
// Remove trivially identical function calls
Calls.sort(); // Sort by callee as primary key!
// Scan the call list cleaning it up as necessary...
DSNodeHandle LastCalleeNode;
Function *LastCalleeFunc = 0;
unsigned NumDuplicateCalls = 0;
bool LastCalleeContainsExternalFunction = false;
unsigned NumDeleted = 0;
for (std::list<DSCallSite>::iterator I = Calls.begin(), E = Calls.end();
I != E;) {
DSCallSite &CS = *I;
std::list<DSCallSite>::iterator OldIt = I++;
if (!CS.isIndirectCall()) {
LastCalleeNode = 0;
} else {
DSNode *Callee = CS.getCalleeNode();
// If the Callee is a useless edge, this must be an unreachable call site,
// eliminate it.
if (Callee->getNumReferrers() == 1 && Callee->isComplete() &&
Callee->getGlobalsList().empty()) { // No useful info?
#ifndef NDEBUG
std::cerr << "WARNING: Useless call site found.\n";
#endif
Calls.erase(OldIt);
++NumDeleted;
continue;
}
// If the last call site in the list has the same callee as this one, and
// if the callee contains an external function, it will never be
// resolvable, just merge the call sites.
if (!LastCalleeNode.isNull() && LastCalleeNode.getNode() == Callee) {
LastCalleeContainsExternalFunction =
nodeContainsExternalFunction(Callee);
std::list<DSCallSite>::iterator PrevIt = OldIt;
--PrevIt;
PrevIt->mergeWith(CS);
// No need to keep this call anymore.
Calls.erase(OldIt);
++NumDeleted;
continue;
} else {
LastCalleeNode = Callee;
}
}
// If the return value or any arguments point to a void node with no
// information at all in it, and the call node is the only node to point
// to it, remove the edge to the node (killing the node).
//
killIfUselessEdge(CS.getRetVal());
for (unsigned a = 0, e = CS.getNumPtrArgs(); a != e; ++a)
killIfUselessEdge(CS.getPtrArg(a));
#if 0
// If this call site calls the same function as the last call site, and if
// the function pointer contains an external function, this node will
// never be resolved. Merge the arguments of the call node because no
// information will be lost.
//
if ((CS.isDirectCall() && CS.getCalleeFunc() == LastCalleeFunc) ||
(CS.isIndirectCall() && CS.getCalleeNode() == LastCalleeNode)) {
++NumDuplicateCalls;
if (NumDuplicateCalls == 1) {
if (LastCalleeNode)
LastCalleeContainsExternalFunction =
nodeContainsExternalFunction(LastCalleeNode);
else
LastCalleeContainsExternalFunction = LastCalleeFunc->isExternal();
}
// It is not clear why, but enabling this code makes DSA really
// sensitive to node forwarding. Basically, with this enabled, DSA
// performs different number of inlinings based on which nodes are
// forwarding or not. This is clearly a problem, so this code is
// disabled until this can be resolved.
#if 1
if (LastCalleeContainsExternalFunction
#if 0
||
// This should be more than enough context sensitivity!
// FIXME: Evaluate how many times this is tripped!
NumDuplicateCalls > 20
#endif
) {
std::list<DSCallSite>::iterator PrevIt = OldIt;
--PrevIt;
PrevIt->mergeWith(CS);
// No need to keep this call anymore.
Calls.erase(OldIt);
++NumDeleted;
continue;
}
#endif
} else {
if (CS.isDirectCall()) {
LastCalleeFunc = CS.getCalleeFunc();
LastCalleeNode = 0;
} else {
LastCalleeNode = CS.getCalleeNode();
LastCalleeFunc = 0;
}
NumDuplicateCalls = 0;
}
#endif
if (I != Calls.end() && CS == *I) {
LastCalleeNode = 0;
Calls.erase(OldIt);
++NumDeleted;
continue;
}
}
// Resort now that we simplified things.
Calls.sort();
// Now that we are in sorted order, eliminate duplicates.
std::list<DSCallSite>::iterator CI = Calls.begin(), CE = Calls.end();
if (CI != CE)
while (1) {
std::list<DSCallSite>::iterator OldIt = CI++;
if (CI == CE) break;
// If this call site is now the same as the previous one, we can delete it
// as a duplicate.
if (*OldIt == *CI) {
Calls.erase(CI);
CI = OldIt;
++NumDeleted;
}
}
//Calls.erase(std::unique(Calls.begin(), Calls.end()), Calls.end());
// Track the number of call nodes merged away...
NumCallNodesMerged += NumDeleted;
DEBUG(if (NumDeleted)
std::cerr << "Merged " << NumDeleted << " call nodes.\n";);
}
// removeTriviallyDeadNodes - After the graph has been constructed, this method
// removes all unreachable nodes that are created because they got merged with
// other nodes in the graph. These nodes will all be trivially unreachable, so
// we don't have to perform any non-trivial analysis here.
//
void DSGraph::removeTriviallyDeadNodes() {
TIME_REGION(X, "removeTriviallyDeadNodes");
#if 0
/// NOTE: This code is disabled. This slows down DSA on 177.mesa
/// substantially!
// Loop over all of the nodes in the graph, calling getNode on each field.
// This will cause all nodes to update their forwarding edges, causing
// forwarded nodes to be delete-able.
{ TIME_REGION(X, "removeTriviallyDeadNodes:node_iterate");
for (node_iterator NI = node_begin(), E = node_end(); NI != E; ++NI) {
DSNode &N = *NI;
for (unsigned l = 0, e = N.getNumLinks(); l != e; ++l)
N.getLink(l*N.getPointerSize()).getNode();
}
}
// NOTE: This code is disabled. Though it should, in theory, allow us to
// remove more nodes down below, the scan of the scalar map is incredibly
// expensive for certain programs (with large SCCs). In the future, if we can
// make the scalar map scan more efficient, then we can reenable this.
{ TIME_REGION(X, "removeTriviallyDeadNodes:scalarmap");
// Likewise, forward any edges from the scalar nodes. While we are at it,
// clean house a bit.
for (DSScalarMap::iterator I = ScalarMap.begin(),E = ScalarMap.end();I != E;){
I->second.getNode();
++I;
}
}
#endif
bool isGlobalsGraph = !GlobalsGraph;
for (NodeListTy::iterator NI = Nodes.begin(), E = Nodes.end(); NI != E; ) {
DSNode &Node = *NI;
// Do not remove *any* global nodes in the globals graph.
// This is a special case because such nodes may not have I, M, R flags set.
if (Node.isGlobalNode() && isGlobalsGraph) {
++NI;
continue;
}
if (Node.isComplete() && !Node.isModified() && !Node.isRead()) {
// This is a useless node if it has no mod/ref info (checked above),
// outgoing edges (which it cannot, as it is not modified in this
// context), and it has no incoming edges. If it is a global node it may
// have all of these properties and still have incoming edges, due to the
// scalar map, so we check those now.
//
if (Node.getNumReferrers() == Node.getGlobalsList().size()) {
const std::vector<GlobalValue*> &Globals = Node.getGlobalsList();
// Loop through and make sure all of the globals are referring directly
// to the node...
for (unsigned j = 0, e = Globals.size(); j != e; ++j) {
DSNode *N = getNodeForValue(Globals[j]).getNode();
assert(N == &Node && "ScalarMap doesn't match globals list!");
}
// Make sure NumReferrers still agrees, if so, the node is truly dead.
if (Node.getNumReferrers() == Globals.size()) {
for (unsigned j = 0, e = Globals.size(); j != e; ++j)
ScalarMap.erase(Globals[j]);
Node.makeNodeDead();
++NumTrivialGlobalDNE;
}
}
}
if (Node.getNodeFlags() == 0 && Node.hasNoReferrers()) {
// This node is dead!
NI = Nodes.erase(NI); // Erase & remove from node list.
++NumTrivialDNE;
} else {
++NI;
}
}
removeIdenticalCalls(FunctionCalls);
removeIdenticalCalls(AuxFunctionCalls);
}
/// markReachableNodes - This method recursively traverses the specified
/// DSNodes, marking any nodes which are reachable. All reachable nodes it adds
/// to the set, which allows it to only traverse visited nodes once.
///
void DSNode::markReachableNodes(hash_set<const DSNode*> &ReachableNodes) const {
if (this == 0) return;
assert(getForwardNode() == 0 && "Cannot mark a forwarded node!");
if (ReachableNodes.insert(this).second) // Is newly reachable?
for (DSNode::const_edge_iterator I = edge_begin(), E = edge_end();
I != E; ++I)
I->getNode()->markReachableNodes(ReachableNodes);
}
void DSCallSite::markReachableNodes(hash_set<const DSNode*> &Nodes) const {
getRetVal().getNode()->markReachableNodes(Nodes);
if (isIndirectCall()) getCalleeNode()->markReachableNodes(Nodes);
for (unsigned i = 0, e = getNumPtrArgs(); i != e; ++i)
getPtrArg(i).getNode()->markReachableNodes(Nodes);
}
// CanReachAliveNodes - Simple graph walker that recursively traverses the graph
// looking for a node that is marked alive. If an alive node is found, return
// true, otherwise return false. If an alive node is reachable, this node is
// marked as alive...
//
static bool CanReachAliveNodes(DSNode *N, hash_set<const DSNode*> &Alive,
hash_set<const DSNode*> &Visited,
bool IgnoreGlobals) {
if (N == 0) return false;
assert(N->getForwardNode() == 0 && "Cannot mark a forwarded node!");
// If this is a global node, it will end up in the globals graph anyway, so we
// don't need to worry about it.
if (IgnoreGlobals && N->isGlobalNode()) return false;
// If we know that this node is alive, return so!
if (Alive.count(N)) return true;
// Otherwise, we don't think the node is alive yet, check for infinite
// recursion.
if (Visited.count(N)) return false; // Found a cycle
Visited.insert(N); // No recursion, insert into Visited...
for (DSNode::edge_iterator I = N->edge_begin(),E = N->edge_end(); I != E; ++I)
if (CanReachAliveNodes(I->getNode(), Alive, Visited, IgnoreGlobals)) {
N->markReachableNodes(Alive);
return true;
}
return false;
}
// CallSiteUsesAliveArgs - Return true if the specified call site can reach any
// alive nodes.
//
static bool CallSiteUsesAliveArgs(const DSCallSite &CS,
hash_set<const DSNode*> &Alive,
hash_set<const DSNode*> &Visited,
bool IgnoreGlobals) {
if (CanReachAliveNodes(CS.getRetVal().getNode(), Alive, Visited,
IgnoreGlobals))
return true;
if (CS.isIndirectCall() &&
CanReachAliveNodes(CS.getCalleeNode(), Alive, Visited, IgnoreGlobals))
return true;
for (unsigned i = 0, e = CS.getNumPtrArgs(); i != e; ++i)
if (CanReachAliveNodes(CS.getPtrArg(i).getNode(), Alive, Visited,
IgnoreGlobals))
return true;
return false;
}
// removeDeadNodes - Use a more powerful reachability analysis to eliminate
// subgraphs that are unreachable. This often occurs because the data
// structure doesn't "escape" into it's caller, and thus should be eliminated
// from the caller's graph entirely. This is only appropriate to use when
// inlining graphs.
//
void DSGraph::removeDeadNodes(unsigned Flags) {
DEBUG(AssertGraphOK(); if (GlobalsGraph) GlobalsGraph->AssertGraphOK());
// Reduce the amount of work we have to do... remove dummy nodes left over by
// merging...
removeTriviallyDeadNodes();
TIME_REGION(X, "removeDeadNodes");
// FIXME: Merge non-trivially identical call nodes...
// Alive - a set that holds all nodes found to be reachable/alive.
hash_set<const DSNode*> Alive;
std::vector<std::pair<Value*, DSNode*> > GlobalNodes;
// Copy and merge all information about globals to the GlobalsGraph if this is
// not a final pass (where unreachable globals are removed).
//
// Strip all alloca bits since the current function is only for the BU pass.
// Strip all incomplete bits since they are short-lived properties and they
// will be correctly computed when rematerializing nodes into the functions.
//
ReachabilityCloner GGCloner(*GlobalsGraph, *this, DSGraph::StripAllocaBit |
DSGraph::StripIncompleteBit);
// Mark all nodes reachable by (non-global) scalar nodes as alive...
{ TIME_REGION(Y, "removeDeadNodes:scalarscan");
for (DSScalarMap::iterator I = ScalarMap.begin(), E = ScalarMap.end();
I != E; ++I)
if (isa<GlobalValue>(I->first)) { // Keep track of global nodes
assert(!I->second.isNull() && "Null global node?");
assert(I->second.getNode()->isGlobalNode() && "Should be a global node!");
GlobalNodes.push_back(std::make_pair(I->first, I->second.getNode()));
// Make sure that all globals are cloned over as roots.
if (!(Flags & DSGraph::RemoveUnreachableGlobals)) {
DSGraph::ScalarMapTy::iterator SMI =
GlobalsGraph->getScalarMap().find(I->first);
if (SMI != GlobalsGraph->getScalarMap().end())
GGCloner.merge(SMI->second, I->second);
else
GGCloner.getClonedNH(I->second);
}
} else {
I->second.getNode()->markReachableNodes(Alive);
}
}
// The return values are alive as well.
for (ReturnNodesTy::iterator I = ReturnNodes.begin(), E = ReturnNodes.end();
I != E; ++I)
I->second.getNode()->markReachableNodes(Alive);
// Mark any nodes reachable by primary calls as alive...
for (fc_iterator I = fc_begin(), E = fc_end(); I != E; ++I)
I->markReachableNodes(Alive);
// Now find globals and aux call nodes that are already live or reach a live
// value (which makes them live in turn), and continue till no more are found.
//
bool Iterate;
hash_set<const DSNode*> Visited;
hash_set<const DSCallSite*> AuxFCallsAlive;
do {
Visited.clear();
// If any global node points to a non-global that is "alive", the global is
// "alive" as well... Remove it from the GlobalNodes list so we only have
// unreachable globals in the list.
//
Iterate = false;
if (!(Flags & DSGraph::RemoveUnreachableGlobals))
for (unsigned i = 0; i != GlobalNodes.size(); ++i)
if (CanReachAliveNodes(GlobalNodes[i].second, Alive, Visited,
Flags & DSGraph::RemoveUnreachableGlobals)) {
std::swap(GlobalNodes[i--], GlobalNodes.back()); // Move to end to...
GlobalNodes.pop_back(); // erase efficiently
Iterate = true;
}
// Mark only unresolvable call nodes for moving to the GlobalsGraph since
// call nodes that get resolved will be difficult to remove from that graph.
// The final unresolved call nodes must be handled specially at the end of
// the BU pass (i.e., in main or other roots of the call graph).
for (afc_iterator CI = afc_begin(), E = afc_end(); CI != E; ++CI)
if (!AuxFCallsAlive.count(&*CI) &&
(CI->isIndirectCall()
|| CallSiteUsesAliveArgs(*CI, Alive, Visited,
Flags & DSGraph::RemoveUnreachableGlobals))) {
CI->markReachableNodes(Alive);
AuxFCallsAlive.insert(&*CI);
Iterate = true;
}
} while (Iterate);
// Move dead aux function calls to the end of the list
unsigned CurIdx = 0;
for (std::list<DSCallSite>::iterator CI = AuxFunctionCalls.begin(),
E = AuxFunctionCalls.end(); CI != E; )
if (AuxFCallsAlive.count(&*CI))
++CI;
else {
// Copy and merge global nodes and dead aux call nodes into the
// GlobalsGraph, and all nodes reachable from those nodes. Update their
// target pointers using the GGCloner.
//
if (!(Flags & DSGraph::RemoveUnreachableGlobals))
GlobalsGraph->AuxFunctionCalls.push_back(DSCallSite(*CI, GGCloner));
AuxFunctionCalls.erase(CI++);
}
// We are finally done with the GGCloner so we can destroy it.
GGCloner.destroy();
// At this point, any nodes which are visited, but not alive, are nodes
// which can be removed. Loop over all nodes, eliminating completely
// unreachable nodes.
//
std::vector<DSNode*> DeadNodes;
DeadNodes.reserve(Nodes.size());
for (NodeListTy::iterator NI = Nodes.begin(), E = Nodes.end(); NI != E;) {
DSNode *N = NI++;
assert(!N->isForwarding() && "Forwarded node in nodes list?");
if (!Alive.count(N)) {
Nodes.remove(N);
assert(!N->isForwarding() && "Cannot remove a forwarding node!");
DeadNodes.push_back(N);
N->dropAllReferences();
++NumDNE;
}
}
// Remove all unreachable globals from the ScalarMap.
// If flag RemoveUnreachableGlobals is set, GlobalNodes has only dead nodes.
// In either case, the dead nodes will not be in the set Alive.
for (unsigned i = 0, e = GlobalNodes.size(); i != e; ++i)
if (!Alive.count(GlobalNodes[i].second))
ScalarMap.erase(GlobalNodes[i].first);
else
assert((Flags & DSGraph::RemoveUnreachableGlobals) && "non-dead global");
// Delete all dead nodes now since their referrer counts are zero.
for (unsigned i = 0, e = DeadNodes.size(); i != e; ++i)
delete DeadNodes[i];
DEBUG(AssertGraphOK(); GlobalsGraph->AssertGraphOK());
}
void DSGraph::AssertNodeContainsGlobal(const DSNode *N, GlobalValue *GV) const {
assert(std::find(N->globals_begin(),N->globals_end(), GV) !=
N->globals_end() && "Global value not in node!");
}
void DSGraph::AssertCallSiteInGraph(const DSCallSite &CS) const {
if (CS.isIndirectCall()) {
AssertNodeInGraph(CS.getCalleeNode());
#if 0
if (CS.getNumPtrArgs() && CS.getCalleeNode() == CS.getPtrArg(0).getNode() &&
CS.getCalleeNode() && CS.getCalleeNode()->getGlobals().empty())
std::cerr << "WARNING: WEIRD CALL SITE FOUND!\n";
#endif
}
AssertNodeInGraph(CS.getRetVal().getNode());
for (unsigned j = 0, e = CS.getNumPtrArgs(); j != e; ++j)
AssertNodeInGraph(CS.getPtrArg(j).getNode());
}
void DSGraph::AssertCallNodesInGraph() const {
for (fc_iterator I = fc_begin(), E = fc_end(); I != E; ++I)
AssertCallSiteInGraph(*I);
}
void DSGraph::AssertAuxCallNodesInGraph() const {
for (afc_iterator I = afc_begin(), E = afc_end(); I != E; ++I)
AssertCallSiteInGraph(*I);
}
void DSGraph::AssertGraphOK() const {
for (node_const_iterator NI = node_begin(), E = node_end(); NI != E; ++NI)
NI->assertOK();
for (ScalarMapTy::const_iterator I = ScalarMap.begin(),
E = ScalarMap.end(); I != E; ++I) {
assert(!I->second.isNull() && "Null node in scalarmap!");
AssertNodeInGraph(I->second.getNode());
if (GlobalValue *GV = dyn_cast<GlobalValue>(I->first)) {
assert(I->second.getNode()->isGlobalNode() &&
"Global points to node, but node isn't global?");
AssertNodeContainsGlobal(I->second.getNode(), GV);
}
}
AssertCallNodesInGraph();
AssertAuxCallNodesInGraph();
// Check that all pointer arguments to any functions in this graph have
// destinations.
for (ReturnNodesTy::const_iterator RI = ReturnNodes.begin(),
E = ReturnNodes.end();
RI != E; ++RI) {
Function &F = *RI->first;
for (Function::arg_iterator AI = F.arg_begin(); AI != F.arg_end(); ++AI)
if (isPointerType(AI->getType()))
assert(!getNodeForValue(AI).isNull() &&
"Pointer argument must be in the scalar map!");
}
}
/// computeNodeMapping - Given roots in two different DSGraphs, traverse the
/// nodes reachable from the two graphs, computing the mapping of nodes from the
/// first to the second graph. This mapping may be many-to-one (i.e. the first
/// graph may have multiple nodes representing one node in the second graph),
/// but it will not work if there is a one-to-many or many-to-many mapping.
///
void DSGraph::computeNodeMapping(const DSNodeHandle &NH1,
const DSNodeHandle &NH2, NodeMapTy &NodeMap,
bool StrictChecking) {
DSNode *N1 = NH1.getNode(), *N2 = NH2.getNode();
if (N1 == 0 || N2 == 0) return;
DSNodeHandle &Entry = NodeMap[N1];
if (!Entry.isNull()) {
// Termination of recursion!
if (StrictChecking) {
assert(Entry.getNode() == N2 && "Inconsistent mapping detected!");
assert((Entry.getOffset() == (NH2.getOffset()-NH1.getOffset()) ||
Entry.getNode()->isNodeCompletelyFolded()) &&
"Inconsistent mapping detected!");
}
return;
}
Entry.setTo(N2, NH2.getOffset()-NH1.getOffset());
// Loop over all of the fields that N1 and N2 have in common, recursively
// mapping the edges together now.
int N2Idx = NH2.getOffset()-NH1.getOffset();
unsigned N2Size = N2->getSize();
if (N2Size == 0) return; // No edges to map to.
for (unsigned i = 0, e = N1->getSize(); i < e; i += DS::PointerSize) {
const DSNodeHandle &N1NH = N1->getLink(i);
// Don't call N2->getLink if not needed (avoiding crash if N2Idx is not
// aligned right).
if (!N1NH.isNull()) {
if (unsigned(N2Idx)+i < N2Size)
computeNodeMapping(N1NH, N2->getLink(N2Idx+i), NodeMap);
else
computeNodeMapping(N1NH,
N2->getLink(unsigned(N2Idx+i) % N2Size), NodeMap);
}
}
}
/// computeGToGGMapping - Compute the mapping of nodes in the global graph to
/// nodes in this graph.
void DSGraph::computeGToGGMapping(NodeMapTy &NodeMap) {
DSGraph &GG = *getGlobalsGraph();
DSScalarMap &SM = getScalarMap();
for (DSScalarMap::global_iterator I = SM.global_begin(),
E = SM.global_end(); I != E; ++I)
DSGraph::computeNodeMapping(SM[*I], GG.getNodeForValue(*I), NodeMap);
}
/// computeGGToGMapping - Compute the mapping of nodes in the global graph to
/// nodes in this graph. Note that any uses of this method are probably bugs,
/// unless it is known that the globals graph has been merged into this graph!
void DSGraph::computeGGToGMapping(InvNodeMapTy &InvNodeMap) {
NodeMapTy NodeMap;
computeGToGGMapping(NodeMap);
while (!NodeMap.empty()) {
InvNodeMap.insert(std::make_pair(NodeMap.begin()->second,
NodeMap.begin()->first));
NodeMap.erase(NodeMap.begin());
}
}
/// computeCalleeCallerMapping - Given a call from a function in the current
/// graph to the 'Callee' function (which lives in 'CalleeGraph'), compute the
/// mapping of nodes from the callee to nodes in the caller.
void DSGraph::computeCalleeCallerMapping(DSCallSite CS, const Function &Callee,
DSGraph &CalleeGraph,
NodeMapTy &NodeMap) {
DSCallSite CalleeArgs =
CalleeGraph.getCallSiteForArguments(const_cast<Function&>(Callee));
computeNodeMapping(CalleeArgs.getRetVal(), CS.getRetVal(), NodeMap);
unsigned NumArgs = CS.getNumPtrArgs();
if (NumArgs > CalleeArgs.getNumPtrArgs())
NumArgs = CalleeArgs.getNumPtrArgs();
for (unsigned i = 0; i != NumArgs; ++i)
computeNodeMapping(CalleeArgs.getPtrArg(i), CS.getPtrArg(i), NodeMap);
// Map the nodes that are pointed to by globals.
DSScalarMap &CalleeSM = CalleeGraph.getScalarMap();
DSScalarMap &CallerSM = getScalarMap();
if (CalleeSM.global_size() >= CallerSM.global_size()) {
for (DSScalarMap::global_iterator GI = CallerSM.global_begin(),
E = CallerSM.global_end(); GI != E; ++GI)
if (CalleeSM.global_count(*GI))
computeNodeMapping(CalleeSM[*GI], CallerSM[*GI], NodeMap);
} else {
for (DSScalarMap::global_iterator GI = CalleeSM.global_begin(),
E = CalleeSM.global_end(); GI != E; ++GI)
if (CallerSM.global_count(*GI))
computeNodeMapping(CalleeSM[*GI], CallerSM[*GI], NodeMap);
}
}
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