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llvm-mirror/lib/Analysis/ModuleSummaryAnalysis.cpp
Teresa Johnson b787681e80 [ThinLTO] Fix "||" vs "|" mixup.
The effect of the bug was that we would incorrectly create summaries
for global and weak values defined in module asm (since we were
essentially testing for bit 1 which is SF_Undefined, and the
RecordStreamer ignores local undefined references). This would have
resulted in conservatively disabling importing of anything referencing
globals and weaks defined in module asm. Added these cases to the test
which now fails without this bug fix.

Fixes PR31459.

llvm-svn: 290610
2016-12-27 17:45:09 +00:00

375 lines
15 KiB
C++

//===- ModuleSummaryAnalysis.cpp - Module summary index builder -----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass builds a ModuleSummaryIndex object for the module, to be written
// to bitcode or LLVM assembly.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/ModuleSummaryAnalysis.h"
#include "llvm/ADT/MapVector.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/IndirectCallPromotionAnalysis.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/TypeMetadataUtils.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/ValueSymbolTable.h"
#include "llvm/Object/IRObjectFile.h"
#include "llvm/Pass.h"
using namespace llvm;
#define DEBUG_TYPE "module-summary-analysis"
// Walk through the operands of a given User via worklist iteration and populate
// the set of GlobalValue references encountered. Invoked either on an
// Instruction or a GlobalVariable (which walks its initializer).
static void findRefEdges(const User *CurUser, SetVector<ValueInfo> &RefEdges,
SmallPtrSet<const User *, 8> &Visited) {
SmallVector<const User *, 32> Worklist;
Worklist.push_back(CurUser);
while (!Worklist.empty()) {
const User *U = Worklist.pop_back_val();
if (!Visited.insert(U).second)
continue;
ImmutableCallSite CS(U);
for (const auto &OI : U->operands()) {
const User *Operand = dyn_cast<User>(OI);
if (!Operand)
continue;
if (isa<BlockAddress>(Operand))
continue;
if (auto *GV = dyn_cast<GlobalValue>(Operand)) {
// We have a reference to a global value. This should be added to
// the reference set unless it is a callee. Callees are handled
// specially by WriteFunction and are added to a separate list.
if (!(CS && CS.isCallee(&OI)))
RefEdges.insert(GV);
continue;
}
Worklist.push_back(Operand);
}
}
}
static CalleeInfo::HotnessType getHotness(uint64_t ProfileCount,
ProfileSummaryInfo *PSI) {
if (!PSI)
return CalleeInfo::HotnessType::Unknown;
if (PSI->isHotCount(ProfileCount))
return CalleeInfo::HotnessType::Hot;
if (PSI->isColdCount(ProfileCount))
return CalleeInfo::HotnessType::Cold;
return CalleeInfo::HotnessType::None;
}
static void computeFunctionSummary(ModuleSummaryIndex &Index, const Module &M,
const Function &F, BlockFrequencyInfo *BFI,
ProfileSummaryInfo *PSI,
bool HasLocalsInUsed) {
// Summary not currently supported for anonymous functions, they should
// have been named.
assert(F.hasName());
unsigned NumInsts = 0;
// Map from callee ValueId to profile count. Used to accumulate profile
// counts for all static calls to a given callee.
MapVector<ValueInfo, CalleeInfo> CallGraphEdges;
SetVector<ValueInfo> RefEdges;
SetVector<GlobalValue::GUID> TypeTests;
ICallPromotionAnalysis ICallAnalysis;
bool HasInlineAsmMaybeReferencingInternal = false;
SmallPtrSet<const User *, 8> Visited;
for (const BasicBlock &BB : F)
for (const Instruction &I : BB) {
if (isa<DbgInfoIntrinsic>(I))
continue;
++NumInsts;
findRefEdges(&I, RefEdges, Visited);
auto CS = ImmutableCallSite(&I);
if (!CS)
continue;
const auto *CI = dyn_cast<CallInst>(&I);
// Since we don't know exactly which local values are referenced in inline
// assembly, conservatively mark the function as possibly referencing
// a local value from inline assembly to ensure we don't export a
// reference (which would require renaming and promotion of the
// referenced value).
if (HasLocalsInUsed && CI && CI->isInlineAsm())
HasInlineAsmMaybeReferencingInternal = true;
auto *CalledValue = CS.getCalledValue();
auto *CalledFunction = CS.getCalledFunction();
// Check if this is an alias to a function. If so, get the
// called aliasee for the checks below.
if (auto *GA = dyn_cast<GlobalAlias>(CalledValue)) {
assert(!CalledFunction && "Expected null called function in callsite for alias");
CalledFunction = dyn_cast<Function>(GA->getBaseObject());
}
// Check if this is a direct call to a known function or a known
// intrinsic, or an indirect call with profile data.
if (CalledFunction) {
if (CalledFunction->isIntrinsic()) {
if (CalledFunction->getIntrinsicID() != Intrinsic::type_test)
continue;
// Produce a summary from type.test intrinsics. We only summarize
// type.test intrinsics that are used other than by an llvm.assume
// intrinsic. Intrinsics that are assumed are relevant only to the
// devirtualization pass, not the type test lowering pass.
bool HasNonAssumeUses = llvm::any_of(CI->uses(), [](const Use &CIU) {
auto *AssumeCI = dyn_cast<CallInst>(CIU.getUser());
if (!AssumeCI)
return true;
Function *F = AssumeCI->getCalledFunction();
return !F || F->getIntrinsicID() != Intrinsic::assume;
});
if (HasNonAssumeUses) {
auto *TypeMDVal = cast<MetadataAsValue>(CI->getArgOperand(1));
if (auto *TypeId = dyn_cast<MDString>(TypeMDVal->getMetadata()))
TypeTests.insert(GlobalValue::getGUID(TypeId->getString()));
}
}
// We should have named any anonymous globals
assert(CalledFunction->hasName());
auto ScaledCount = BFI ? BFI->getBlockProfileCount(&BB) : None;
auto Hotness = ScaledCount ? getHotness(ScaledCount.getValue(), PSI)
: CalleeInfo::HotnessType::Unknown;
// Use the original CalledValue, in case it was an alias. We want
// to record the call edge to the alias in that case. Eventually
// an alias summary will be created to associate the alias and
// aliasee.
CallGraphEdges[cast<GlobalValue>(CalledValue)].updateHotness(Hotness);
} else {
// Skip inline assembly calls.
if (CI && CI->isInlineAsm())
continue;
// Skip direct calls.
if (!CS.getCalledValue() || isa<Constant>(CS.getCalledValue()))
continue;
uint32_t NumVals, NumCandidates;
uint64_t TotalCount;
auto CandidateProfileData =
ICallAnalysis.getPromotionCandidatesForInstruction(
&I, NumVals, TotalCount, NumCandidates);
for (auto &Candidate : CandidateProfileData)
CallGraphEdges[Candidate.Value].updateHotness(
getHotness(Candidate.Count, PSI));
}
}
GlobalValueSummary::GVFlags Flags(F);
auto FuncSummary = llvm::make_unique<FunctionSummary>(
Flags, NumInsts, RefEdges.takeVector(), CallGraphEdges.takeVector(),
TypeTests.takeVector());
if (HasInlineAsmMaybeReferencingInternal)
FuncSummary->setHasInlineAsmMaybeReferencingInternal();
Index.addGlobalValueSummary(F.getName(), std::move(FuncSummary));
}
static void computeVariableSummary(ModuleSummaryIndex &Index,
const GlobalVariable &V) {
SetVector<ValueInfo> RefEdges;
SmallPtrSet<const User *, 8> Visited;
findRefEdges(&V, RefEdges, Visited);
GlobalValueSummary::GVFlags Flags(V);
auto GVarSummary =
llvm::make_unique<GlobalVarSummary>(Flags, RefEdges.takeVector());
Index.addGlobalValueSummary(V.getName(), std::move(GVarSummary));
}
static void computeAliasSummary(ModuleSummaryIndex &Index,
const GlobalAlias &A) {
GlobalValueSummary::GVFlags Flags(A);
auto AS = llvm::make_unique<AliasSummary>(Flags, ArrayRef<ValueInfo>{});
auto *Aliasee = A.getBaseObject();
auto *AliaseeSummary = Index.getGlobalValueSummary(*Aliasee);
assert(AliaseeSummary && "Alias expects aliasee summary to be parsed");
AS->setAliasee(AliaseeSummary);
Index.addGlobalValueSummary(A.getName(), std::move(AS));
}
ModuleSummaryIndex llvm::buildModuleSummaryIndex(
const Module &M,
std::function<BlockFrequencyInfo *(const Function &F)> GetBFICallback,
ProfileSummaryInfo *PSI) {
ModuleSummaryIndex Index;
// Identify the local values in the llvm.used and llvm.compiler.used sets,
// which should not be exported as they would then require renaming and
// promotion, but we may have opaque uses e.g. in inline asm. We collect them
// here because we use this information to mark functions containing inline
// assembly calls as not importable.
SmallPtrSet<GlobalValue *, 8> LocalsUsed;
SmallPtrSet<GlobalValue *, 8> Used;
// First collect those in the llvm.used set.
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ false);
// Next collect those in the llvm.compiler.used set.
collectUsedGlobalVariables(M, Used, /*CompilerUsed*/ true);
for (auto *V : Used) {
if (V->hasLocalLinkage())
LocalsUsed.insert(V);
}
// Compute summaries for all functions defined in module, and save in the
// index.
for (auto &F : M) {
if (F.isDeclaration())
continue;
BlockFrequencyInfo *BFI = nullptr;
std::unique_ptr<BlockFrequencyInfo> BFIPtr;
if (GetBFICallback)
BFI = GetBFICallback(F);
else if (F.getEntryCount().hasValue()) {
LoopInfo LI{DominatorTree(const_cast<Function &>(F))};
BranchProbabilityInfo BPI{F, LI};
BFIPtr = llvm::make_unique<BlockFrequencyInfo>(F, BPI, LI);
BFI = BFIPtr.get();
}
computeFunctionSummary(Index, M, F, BFI, PSI, !LocalsUsed.empty());
}
// Compute summaries for all variables defined in module, and save in the
// index.
for (const GlobalVariable &G : M.globals()) {
if (G.isDeclaration())
continue;
computeVariableSummary(Index, G);
}
// Compute summaries for all aliases defined in module, and save in the
// index.
for (const GlobalAlias &A : M.aliases())
computeAliasSummary(Index, A);
for (auto *V : LocalsUsed) {
auto *Summary = Index.getGlobalValueSummary(*V);
assert(Summary && "Missing summary for global value");
Summary->setNoRename();
}
if (!M.getModuleInlineAsm().empty()) {
// Collect the local values defined by module level asm, and set up
// summaries for these symbols so that they can be marked as NoRename,
// to prevent export of any use of them in regular IR that would require
// renaming within the module level asm. Note we don't need to create a
// summary for weak or global defs, as they don't need to be flagged as
// NoRename, and defs in module level asm can't be imported anyway.
// Also, any values used but not defined within module level asm should
// be listed on the llvm.used or llvm.compiler.used global and marked as
// referenced from there.
ModuleSymbolTable::CollectAsmSymbols(
Triple(M.getTargetTriple()), M.getModuleInlineAsm(),
[&M, &Index](StringRef Name, object::BasicSymbolRef::Flags Flags) {
// Symbols not marked as Weak or Global are local definitions.
if (Flags & (object::BasicSymbolRef::SF_Weak |
object::BasicSymbolRef::SF_Global))
return;
GlobalValue *GV = M.getNamedValue(Name);
if (!GV)
return;
assert(GV->isDeclaration() && "Def in module asm already has definition");
GlobalValueSummary::GVFlags GVFlags(
GlobalValue::InternalLinkage,
/* NoRename */ true,
/* HasInlineAsmMaybeReferencingInternal */ false,
/* IsNotViableToInline */ true);
// Create the appropriate summary type.
if (isa<Function>(GV)) {
std::unique_ptr<FunctionSummary> Summary =
llvm::make_unique<FunctionSummary>(
GVFlags, 0, ArrayRef<ValueInfo>{},
ArrayRef<FunctionSummary::EdgeTy>{},
ArrayRef<GlobalValue::GUID>{});
Summary->setNoRename();
Index.addGlobalValueSummary(Name, std::move(Summary));
} else {
std::unique_ptr<GlobalVarSummary> Summary =
llvm::make_unique<GlobalVarSummary>(GVFlags,
ArrayRef<ValueInfo>{});
Summary->setNoRename();
Index.addGlobalValueSummary(Name, std::move(Summary));
}
});
}
return Index;
}
AnalysisKey ModuleSummaryIndexAnalysis::Key;
ModuleSummaryIndex
ModuleSummaryIndexAnalysis::run(Module &M, ModuleAnalysisManager &AM) {
ProfileSummaryInfo &PSI = AM.getResult<ProfileSummaryAnalysis>(M);
auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
return buildModuleSummaryIndex(
M,
[&FAM](const Function &F) {
return &FAM.getResult<BlockFrequencyAnalysis>(
*const_cast<Function *>(&F));
},
&PSI);
}
char ModuleSummaryIndexWrapperPass::ID = 0;
INITIALIZE_PASS_BEGIN(ModuleSummaryIndexWrapperPass, "module-summary-analysis",
"Module Summary Analysis", false, true)
INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
INITIALIZE_PASS_END(ModuleSummaryIndexWrapperPass, "module-summary-analysis",
"Module Summary Analysis", false, true)
ModulePass *llvm::createModuleSummaryIndexWrapperPass() {
return new ModuleSummaryIndexWrapperPass();
}
ModuleSummaryIndexWrapperPass::ModuleSummaryIndexWrapperPass()
: ModulePass(ID) {
initializeModuleSummaryIndexWrapperPassPass(*PassRegistry::getPassRegistry());
}
bool ModuleSummaryIndexWrapperPass::runOnModule(Module &M) {
auto &PSI = *getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
Index = buildModuleSummaryIndex(
M,
[this](const Function &F) {
return &(this->getAnalysis<BlockFrequencyInfoWrapperPass>(
*const_cast<Function *>(&F))
.getBFI());
},
&PSI);
return false;
}
bool ModuleSummaryIndexWrapperPass::doFinalization(Module &M) {
Index.reset();
return false;
}
void ModuleSummaryIndexWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<BlockFrequencyInfoWrapperPass>();
AU.addRequired<ProfileSummaryInfoWrapperPass>();
}