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llvm-mirror/lib/IR/LLVMContext.cpp
Peter Collingbourne e3f12b0e68 IR: New representation for CFI and virtual call optimization pass metadata.
The bitset metadata currently used in LLVM has a few problems:

1. It has the wrong name. The name "bitset" refers to an implementation
   detail of one use of the metadata (i.e. its original use case, CFI).
   This makes it harder to understand, as the name makes no sense in the
   context of virtual call optimization.

2. It is represented using a global named metadata node, rather than
   being directly associated with a global. This makes it harder to
   manipulate the metadata when rebuilding global variables, summarise it
   as part of ThinLTO and drop unused metadata when associated globals are
   dropped. For this reason, CFI does not currently work correctly when
   both CFI and vcall opt are enabled, as vcall opt needs to rebuild vtable
   globals, and fails to associate metadata with the rebuilt globals. As I
   understand it, the same problem could also affect ASan, which rebuilds
   globals with a red zone.

This patch solves both of those problems in the following way:

1. Rename the metadata to "type metadata". This new name reflects how
   the metadata is currently being used (i.e. to represent type information
   for CFI and vtable opt). The new name is reflected in the name for the
   associated intrinsic (llvm.type.test) and pass (LowerTypeTests).

2. Attach metadata directly to the globals that it pertains to, rather
   than using the "llvm.bitsets" global metadata node as we are doing now.
   This is done using the newly introduced capability to attach
   metadata to global variables (r271348 and r271358).

See also: http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html

Differential Revision: http://reviews.llvm.org/D21053

llvm-svn: 273729
2016-06-24 21:21:32 +00:00

347 lines
11 KiB
C++

//===-- LLVMContext.cpp - Implement LLVMContext ---------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements LLVMContext, as a wrapper around the opaque
// class LLVMContextImpl.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/LLVMContext.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include "LLVMContextImpl.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdlib>
#include <string>
#include <utility>
using namespace llvm;
LLVMContext::LLVMContext() : pImpl(new LLVMContextImpl(*this)) {
// Create the fixed metadata kinds. This is done in the same order as the
// MD_* enum values so that they correspond.
// Create the 'dbg' metadata kind.
unsigned DbgID = getMDKindID("dbg");
assert(DbgID == MD_dbg && "dbg kind id drifted"); (void)DbgID;
// Create the 'tbaa' metadata kind.
unsigned TBAAID = getMDKindID("tbaa");
assert(TBAAID == MD_tbaa && "tbaa kind id drifted"); (void)TBAAID;
// Create the 'prof' metadata kind.
unsigned ProfID = getMDKindID("prof");
assert(ProfID == MD_prof && "prof kind id drifted"); (void)ProfID;
// Create the 'fpmath' metadata kind.
unsigned FPAccuracyID = getMDKindID("fpmath");
assert(FPAccuracyID == MD_fpmath && "fpmath kind id drifted");
(void)FPAccuracyID;
// Create the 'range' metadata kind.
unsigned RangeID = getMDKindID("range");
assert(RangeID == MD_range && "range kind id drifted");
(void)RangeID;
// Create the 'tbaa.struct' metadata kind.
unsigned TBAAStructID = getMDKindID("tbaa.struct");
assert(TBAAStructID == MD_tbaa_struct && "tbaa.struct kind id drifted");
(void)TBAAStructID;
// Create the 'invariant.load' metadata kind.
unsigned InvariantLdId = getMDKindID("invariant.load");
assert(InvariantLdId == MD_invariant_load && "invariant.load kind id drifted");
(void)InvariantLdId;
// Create the 'alias.scope' metadata kind.
unsigned AliasScopeID = getMDKindID("alias.scope");
assert(AliasScopeID == MD_alias_scope && "alias.scope kind id drifted");
(void)AliasScopeID;
// Create the 'noalias' metadata kind.
unsigned NoAliasID = getMDKindID("noalias");
assert(NoAliasID == MD_noalias && "noalias kind id drifted");
(void)NoAliasID;
// Create the 'nontemporal' metadata kind.
unsigned NonTemporalID = getMDKindID("nontemporal");
assert(NonTemporalID == MD_nontemporal && "nontemporal kind id drifted");
(void)NonTemporalID;
// Create the 'llvm.mem.parallel_loop_access' metadata kind.
unsigned MemParallelLoopAccessID = getMDKindID("llvm.mem.parallel_loop_access");
assert(MemParallelLoopAccessID == MD_mem_parallel_loop_access &&
"mem_parallel_loop_access kind id drifted");
(void)MemParallelLoopAccessID;
// Create the 'nonnull' metadata kind.
unsigned NonNullID = getMDKindID("nonnull");
assert(NonNullID == MD_nonnull && "nonnull kind id drifted");
(void)NonNullID;
// Create the 'dereferenceable' metadata kind.
unsigned DereferenceableID = getMDKindID("dereferenceable");
assert(DereferenceableID == MD_dereferenceable &&
"dereferenceable kind id drifted");
(void)DereferenceableID;
// Create the 'dereferenceable_or_null' metadata kind.
unsigned DereferenceableOrNullID = getMDKindID("dereferenceable_or_null");
assert(DereferenceableOrNullID == MD_dereferenceable_or_null &&
"dereferenceable_or_null kind id drifted");
(void)DereferenceableOrNullID;
// Create the 'make.implicit' metadata kind.
unsigned MakeImplicitID = getMDKindID("make.implicit");
assert(MakeImplicitID == MD_make_implicit &&
"make.implicit kind id drifted");
(void)MakeImplicitID;
// Create the 'unpredictable' metadata kind.
unsigned UnpredictableID = getMDKindID("unpredictable");
assert(UnpredictableID == MD_unpredictable &&
"unpredictable kind id drifted");
(void)UnpredictableID;
// Create the 'invariant.group' metadata kind.
unsigned InvariantGroupId = getMDKindID("invariant.group");
assert(InvariantGroupId == MD_invariant_group &&
"invariant.group kind id drifted");
(void)InvariantGroupId;
// Create the 'align' metadata kind.
unsigned AlignID = getMDKindID("align");
assert(AlignID == MD_align && "align kind id drifted");
(void)AlignID;
// Create the 'llvm.loop' metadata kind.
unsigned LoopID = getMDKindID("llvm.loop");
assert(LoopID == MD_loop && "llvm.loop kind id drifted");
(void)LoopID;
unsigned TypeID = getMDKindID("type");
assert(TypeID == MD_type && "type kind id drifted");
(void)TypeID;
auto *DeoptEntry = pImpl->getOrInsertBundleTag("deopt");
assert(DeoptEntry->second == LLVMContext::OB_deopt &&
"deopt operand bundle id drifted!");
(void)DeoptEntry;
auto *FuncletEntry = pImpl->getOrInsertBundleTag("funclet");
assert(FuncletEntry->second == LLVMContext::OB_funclet &&
"funclet operand bundle id drifted!");
(void)FuncletEntry;
auto *GCTransitionEntry = pImpl->getOrInsertBundleTag("gc-transition");
assert(GCTransitionEntry->second == LLVMContext::OB_gc_transition &&
"gc-transition operand bundle id drifted!");
(void)GCTransitionEntry;
}
LLVMContext::~LLVMContext() { delete pImpl; }
void LLVMContext::addModule(Module *M) {
pImpl->OwnedModules.insert(M);
}
void LLVMContext::removeModule(Module *M) {
pImpl->OwnedModules.erase(M);
}
//===----------------------------------------------------------------------===//
// Recoverable Backend Errors
//===----------------------------------------------------------------------===//
void LLVMContext::
setInlineAsmDiagnosticHandler(InlineAsmDiagHandlerTy DiagHandler,
void *DiagContext) {
pImpl->InlineAsmDiagHandler = DiagHandler;
pImpl->InlineAsmDiagContext = DiagContext;
}
/// getInlineAsmDiagnosticHandler - Return the diagnostic handler set by
/// setInlineAsmDiagnosticHandler.
LLVMContext::InlineAsmDiagHandlerTy
LLVMContext::getInlineAsmDiagnosticHandler() const {
return pImpl->InlineAsmDiagHandler;
}
/// getInlineAsmDiagnosticContext - Return the diagnostic context set by
/// setInlineAsmDiagnosticHandler.
void *LLVMContext::getInlineAsmDiagnosticContext() const {
return pImpl->InlineAsmDiagContext;
}
void LLVMContext::setDiagnosticHandler(DiagnosticHandlerTy DiagnosticHandler,
void *DiagnosticContext,
bool RespectFilters) {
pImpl->DiagnosticHandler = DiagnosticHandler;
pImpl->DiagnosticContext = DiagnosticContext;
pImpl->RespectDiagnosticFilters = RespectFilters;
}
LLVMContext::DiagnosticHandlerTy LLVMContext::getDiagnosticHandler() const {
return pImpl->DiagnosticHandler;
}
void *LLVMContext::getDiagnosticContext() const {
return pImpl->DiagnosticContext;
}
void LLVMContext::setYieldCallback(YieldCallbackTy Callback, void *OpaqueHandle)
{
pImpl->YieldCallback = Callback;
pImpl->YieldOpaqueHandle = OpaqueHandle;
}
void LLVMContext::yield() {
if (pImpl->YieldCallback)
pImpl->YieldCallback(this, pImpl->YieldOpaqueHandle);
}
void LLVMContext::emitError(const Twine &ErrorStr) {
diagnose(DiagnosticInfoInlineAsm(ErrorStr));
}
void LLVMContext::emitError(const Instruction *I, const Twine &ErrorStr) {
assert (I && "Invalid instruction");
diagnose(DiagnosticInfoInlineAsm(*I, ErrorStr));
}
static bool isDiagnosticEnabled(const DiagnosticInfo &DI) {
// Optimization remarks are selective. They need to check whether the regexp
// pattern, passed via one of the -pass-remarks* flags, matches the name of
// the pass that is emitting the diagnostic. If there is no match, ignore the
// diagnostic and return.
if (auto *Remark = dyn_cast<DiagnosticInfoOptimizationBase>(&DI))
return Remark->isEnabled();
return true;
}
const char *
LLVMContext::getDiagnosticMessagePrefix(DiagnosticSeverity Severity) {
switch (Severity) {
case DS_Error:
return "error";
case DS_Warning:
return "warning";
case DS_Remark:
return "remark";
case DS_Note:
return "note";
}
llvm_unreachable("Unknown DiagnosticSeverity");
}
void LLVMContext::diagnose(const DiagnosticInfo &DI) {
// If there is a report handler, use it.
if (pImpl->DiagnosticHandler) {
if (!pImpl->RespectDiagnosticFilters || isDiagnosticEnabled(DI))
pImpl->DiagnosticHandler(DI, pImpl->DiagnosticContext);
return;
}
if (!isDiagnosticEnabled(DI))
return;
// Otherwise, print the message with a prefix based on the severity.
DiagnosticPrinterRawOStream DP(errs());
errs() << getDiagnosticMessagePrefix(DI.getSeverity()) << ": ";
DI.print(DP);
errs() << "\n";
if (DI.getSeverity() == DS_Error)
exit(1);
}
void LLVMContext::emitError(unsigned LocCookie, const Twine &ErrorStr) {
diagnose(DiagnosticInfoInlineAsm(LocCookie, ErrorStr));
}
//===----------------------------------------------------------------------===//
// Metadata Kind Uniquing
//===----------------------------------------------------------------------===//
/// Return a unique non-zero ID for the specified metadata kind.
unsigned LLVMContext::getMDKindID(StringRef Name) const {
// If this is new, assign it its ID.
return pImpl->CustomMDKindNames.insert(
std::make_pair(
Name, pImpl->CustomMDKindNames.size()))
.first->second;
}
/// getHandlerNames - Populate client-supplied smallvector using custom
/// metadata name and ID.
void LLVMContext::getMDKindNames(SmallVectorImpl<StringRef> &Names) const {
Names.resize(pImpl->CustomMDKindNames.size());
for (StringMap<unsigned>::const_iterator I = pImpl->CustomMDKindNames.begin(),
E = pImpl->CustomMDKindNames.end(); I != E; ++I)
Names[I->second] = I->first();
}
void LLVMContext::getOperandBundleTags(SmallVectorImpl<StringRef> &Tags) const {
pImpl->getOperandBundleTags(Tags);
}
uint32_t LLVMContext::getOperandBundleTagID(StringRef Tag) const {
return pImpl->getOperandBundleTagID(Tag);
}
void LLVMContext::setGC(const Function &Fn, std::string GCName) {
auto It = pImpl->GCNames.find(&Fn);
if (It == pImpl->GCNames.end()) {
pImpl->GCNames.insert(std::make_pair(&Fn, std::move(GCName)));
return;
}
It->second = std::move(GCName);
}
const std::string &LLVMContext::getGC(const Function &Fn) {
return pImpl->GCNames[&Fn];
}
void LLVMContext::deleteGC(const Function &Fn) {
pImpl->GCNames.erase(&Fn);
}
bool LLVMContext::shouldDiscardValueNames() const {
return pImpl->DiscardValueNames;
}
bool LLVMContext::isODRUniquingDebugTypes() const { return !!pImpl->DITypeMap; }
void LLVMContext::enableDebugTypeODRUniquing() {
if (pImpl->DITypeMap)
return;
pImpl->DITypeMap.emplace();
}
void LLVMContext::disableDebugTypeODRUniquing() { pImpl->DITypeMap.reset(); }
void LLVMContext::setDiscardValueNames(bool Discard) {
pImpl->DiscardValueNames = Discard;
}
OptBisect &LLVMContext::getOptBisect() {
return pImpl->getOptBisect();
}