[llvm] [CGData] Global Merge Functions (PR #112671)
Kyungwoo Lee via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 11 00:52:20 PST 2024
https://github.com/kyulee-com updated https://github.com/llvm/llvm-project/pull/112671
>From 4e2d83d8675799da1a5c6b57d285ecefc0285c71 Mon Sep 17 00:00:00 2001
From: Kyungwoo Lee <kyulee at meta.com>
Date: Fri, 30 Aug 2024 00:09:09 -0700
Subject: [PATCH 1/7] [CGData] Global Merge Functions
---
llvm/include/llvm/CGData/CodeGenData.h | 11 +
llvm/include/llvm/InitializePasses.h | 1 +
llvm/include/llvm/LinkAllPasses.h | 1 +
llvm/include/llvm/Transforms/IPO.h | 2 +
.../Transforms/IPO/GlobalMergeFunctions.h | 77 ++
llvm/lib/CodeGen/TargetPassConfig.cpp | 3 +
llvm/lib/LTO/LTO.cpp | 1 +
llvm/lib/Transforms/IPO/CMakeLists.txt | 2 +
.../Transforms/IPO/GlobalMergeFunctions.cpp | 747 ++++++++++++++++++
.../ThinLTO/AArch64/cgdata-merge-local.ll | 62 ++
.../test/ThinLTO/AArch64/cgdata-merge-read.ll | 82 ++
.../AArch64/cgdata-merge-two-rounds.ll | 68 ++
.../ThinLTO/AArch64/cgdata-merge-write.ll | 97 +++
llvm/tools/llvm-lto2/CMakeLists.txt | 1 +
llvm/tools/llvm-lto2/llvm-lto2.cpp | 6 +
15 files changed, 1161 insertions(+)
create mode 100644 llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
create mode 100644 llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
create mode 100644 llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll
create mode 100644 llvm/test/ThinLTO/AArch64/cgdata-merge-read.ll
create mode 100644 llvm/test/ThinLTO/AArch64/cgdata-merge-two-rounds.ll
create mode 100644 llvm/test/ThinLTO/AArch64/cgdata-merge-write.ll
diff --git a/llvm/include/llvm/CGData/CodeGenData.h b/llvm/include/llvm/CGData/CodeGenData.h
index 5d7c74725ccef1..da0e412f2a0e03 100644
--- a/llvm/include/llvm/CGData/CodeGenData.h
+++ b/llvm/include/llvm/CGData/CodeGenData.h
@@ -145,6 +145,9 @@ class CodeGenData {
const OutlinedHashTree *getOutlinedHashTree() {
return PublishedHashTree.get();
}
+ const StableFunctionMap *getStableFunctionMap() {
+ return PublishedStableFunctionMap.get();
+ }
/// Returns true if we should write codegen data.
bool emitCGData() { return EmitCGData; }
@@ -169,10 +172,18 @@ inline bool hasOutlinedHashTree() {
return CodeGenData::getInstance().hasOutlinedHashTree();
}
+inline bool hasStableFunctionMap() {
+ return CodeGenData::getInstance().hasStableFunctionMap();
+}
+
inline const OutlinedHashTree *getOutlinedHashTree() {
return CodeGenData::getInstance().getOutlinedHashTree();
}
+inline const StableFunctionMap *getStableFunctionMap() {
+ return CodeGenData::getInstance().getStableFunctionMap();
+}
+
inline bool emitCGData() { return CodeGenData::getInstance().emitCGData(); }
inline void
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 54c070401ec8a4..a43a96e90543cc 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -123,6 +123,7 @@ void initializeGCEmptyBasicBlocksPass(PassRegistry &);
void initializeGCMachineCodeAnalysisPass(PassRegistry &);
void initializeGCModuleInfoPass(PassRegistry &);
void initializeGVNLegacyPassPass(PassRegistry &);
+void initializeGlobalMergeFuncPass(PassRegistry &);
void initializeGlobalMergePass(PassRegistry &);
void initializeGlobalsAAWrapperPassPass(PassRegistry &);
void initializeHardwareLoopsLegacyPass(PassRegistry &);
diff --git a/llvm/include/llvm/LinkAllPasses.h b/llvm/include/llvm/LinkAllPasses.h
index 3516b47d29ef36..d1219d6ee2a13e 100644
--- a/llvm/include/llvm/LinkAllPasses.h
+++ b/llvm/include/llvm/LinkAllPasses.h
@@ -79,6 +79,7 @@ struct ForcePassLinking {
(void)llvm::createDomOnlyViewerWrapperPassPass();
(void)llvm::createDomViewerWrapperPassPass();
(void)llvm::createAlwaysInlinerLegacyPass();
+ (void)llvm::createGlobalMergeFuncPass();
(void)llvm::createGlobalsAAWrapperPass();
(void)llvm::createInstSimplifyLegacyPass();
(void)llvm::createInstructionCombiningPass();
diff --git a/llvm/include/llvm/Transforms/IPO.h b/llvm/include/llvm/Transforms/IPO.h
index ee0e35aa618325..86a8654f56997c 100644
--- a/llvm/include/llvm/Transforms/IPO.h
+++ b/llvm/include/llvm/Transforms/IPO.h
@@ -55,6 +55,8 @@ enum class PassSummaryAction {
Export, ///< Export information to summary.
};
+Pass *createGlobalMergeFuncPass();
+
} // End llvm namespace
#endif
diff --git a/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h b/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
new file mode 100644
index 00000000000000..565be54f89e882
--- /dev/null
+++ b/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
@@ -0,0 +1,77 @@
+//===------ GlobalMergeFunctions.h - Global merge functions -----*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file defines global merge functions pass and related data structure.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef PIKA_TRANSFORMS_UTILS_GLOBALMERGEFUNCTIONS_H
+#define PIKA_TRANSFORMS_UTILS_GLOBALMERGEFUNCTIONS_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/StableHashing.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/CGData/StableFunctionMap.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include <map>
+#include <mutex>
+
+enum class HashFunctionMode {
+ Local,
+ BuildingHashFuncion,
+ UsingHashFunction,
+};
+
+namespace llvm {
+
+// A vector of locations (the pair of (instruction, operand) indices) reachable
+// from a parameter.
+using ParamLocs = SmallVector<IndexPair, 4>;
+// A vector of parameters
+using ParamLocsVecTy = SmallVector<ParamLocs, 8>;
+// A map of stable hash to a vector of stable functions
+
+/// GlobalMergeFunc finds functions which only differ by constants in
+/// certain instructions, e.g. resulting from specialized functions of layout
+/// compatible types.
+/// Unlike PikaMergeFunc that directly compares IRs, this uses stable function
+/// hash to find the merge candidate. Similar to the global outliner, we can run
+/// codegen twice to collect function merge candidate in the first round, and
+/// merge functions globally in the second round.
+class GlobalMergeFunc : public ModulePass {
+ HashFunctionMode MergerMode = HashFunctionMode::Local;
+
+ std::unique_ptr<StableFunctionMap> LocalFunctionMap;
+
+public:
+ static char ID;
+
+ GlobalMergeFunc();
+
+ StringRef getPassName() const override;
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override;
+
+ void initializeMergerMode(const Module &M);
+
+ bool runOnModule(Module &M) override;
+
+ /// Analyze module to create stable function into LocalFunctionMap.
+ void analyze(Module &M);
+
+ /// Emit LocalFunctionMap into __llvm_merge section.
+ void emitFunctionMap(Module &M);
+
+ /// Merge functions in the module using the global function map.
+ bool merge(Module &M, const StableFunctionMap *FunctionMap);
+};
+
+} // end namespace llvm
+#endif // PIKA_TRANSFORMS_UTILS_GLOBALMERGEFUNCTIONS_H
diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index aff74104006e5a..beeb8ea2d078d9 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -141,6 +141,9 @@ static cl::opt<RunOutliner> EnableMachineOutliner(
"Disable all outlining"),
// Sentinel value for unspecified option.
clEnumValN(RunOutliner::AlwaysOutline, "", "")));
+cl::opt<bool> EnableGlobalMergeFunc(
+ "enable-global-merge-func", cl::Hidden,
+ cl::desc("Enable global merge functions that are based on hash function"));
// Disable the pass to fix unwind information. Whether the pass is included in
// the pipeline is controlled via the target options, this option serves as
// manual override.
diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 0f53c608512171..3f88c6c475d4d8 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -53,6 +53,7 @@
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/IPO/GlobalMergeFunctions.h"
#include "llvm/Transforms/IPO/MemProfContextDisambiguation.h"
#include "llvm/Transforms/IPO/WholeProgramDevirt.h"
#include "llvm/Transforms/Utils/FunctionImportUtils.h"
diff --git a/llvm/lib/Transforms/IPO/CMakeLists.txt b/llvm/lib/Transforms/IPO/CMakeLists.txt
index 15cb57399d2460..6a36ed64149f93 100644
--- a/llvm/lib/Transforms/IPO/CMakeLists.txt
+++ b/llvm/lib/Transforms/IPO/CMakeLists.txt
@@ -21,6 +21,7 @@ add_llvm_component_library(LLVMipo
GlobalDCE.cpp
GlobalOpt.cpp
GlobalSplit.cpp
+ GlobalMergeFunctions.cpp
HotColdSplitting.cpp
IPO.cpp
IROutliner.cpp
@@ -60,6 +61,7 @@ add_llvm_component_library(LLVMipo
Analysis
BitReader
BitWriter
+ CGData
Core
FrontendOpenMP
InstCombine
diff --git a/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp b/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
new file mode 100644
index 00000000000000..6fd1a66b5a197c
--- /dev/null
+++ b/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
@@ -0,0 +1,747 @@
+//===---- GlobalMergeFunctions.cpp - Global merge functions -------*- C++ -===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// TODO: This implements a function merge using function hash while tracking
+// differences in Constants. This uses stable function hash to find potential
+// merge candidates. The first codegen round collects stable function hashes,
+// and determines the merge candidates that match the stable function hashes.
+// The set of parameters pointing to different Constants are also computed
+// during the stable function merge. The second codegen round uses this global
+// function info to optimistically create a merged function in each module
+// context to guarantee correct transformation. Similar to the global outliner,
+// the linker's deduplication (ICF) folds the identical merged functions to save
+// the final binary size.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/IPO/GlobalMergeFunctions.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/ModuleSummaryAnalysis.h"
+#include "llvm/CGData/CodeGenData.h"
+#include "llvm/CGData/StableFunctionMap.h"
+#include "llvm/CodeGen/MachineStableHash.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/StructuralHash.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Transforms/Utils/ModuleUtils.h"
+
+#define DEBUG_TYPE "global-merge-func"
+
+using namespace llvm;
+using namespace llvm::support;
+
+static cl::opt<bool>
+ DisableGlobalMerging("disable-global-merging", cl::Hidden,
+ cl::desc("Disable global merging only by ignoring "
+ "the codegen data generation or use. Local "
+ "merging is still enabled within a module."),
+ cl::init(false));
+static cl::opt<unsigned> GlobalMergingMinInstrs(
+ "global-merging-min-instrs",
+ cl::desc("The minimum instruction count required when merging functions."),
+ cl::init(1), cl::Hidden);
+static cl::opt<unsigned> GlobalMergingMaxParams(
+ "global-merging-max-params",
+ cl::desc(
+ "The maximum number of parameters allowed when merging functions."),
+ cl::init(std::numeric_limits<unsigned>::max()), cl::Hidden);
+static cl::opt<unsigned> GlobalMergingParamOverhead(
+ "global-merging-param-overhead",
+ cl::desc("The overhead cost associated with each parameter when merging "
+ "functions."),
+ cl::init(2), cl::Hidden);
+static cl::opt<unsigned>
+ GlobalMergingCallOverhead("global-merging-call-overhead",
+ cl::desc("The overhead cost associated with each "
+ "function call when merging functions."),
+ cl::init(1), cl::Hidden);
+static cl::opt<unsigned> GlobalMergingExtraThreshold(
+ "global-merging-extra-threshold",
+ cl::desc("An additional cost threshold that must be exceeded for merging "
+ "to be considered beneficial."),
+ cl::init(0), cl::Hidden);
+
+extern cl::opt<bool> EnableGlobalMergeFunc;
+
+STATISTIC(NumMismatchedFunctionHashGlobalMergeFunction,
+ "Number of mismatched function hash for global merge function");
+STATISTIC(NumMismatchedInstCountGlobalMergeFunction,
+ "Number of mismatched instruction count for global merge function");
+STATISTIC(NumMismatchedConstHashGlobalMergeFunction,
+ "Number of mismatched const hash for global merge function");
+STATISTIC(NumMismatchedModuleIdGlobalMergeFunction,
+ "Number of mismatched Module Id for global merge function");
+STATISTIC(NumGlobalMergeFunctions,
+ "Number of functions that are actually merged using function hash");
+STATISTIC(NumAnalyzedModues, "Number of modules that are analyzed");
+STATISTIC(NumAnalyzedFunctions, "Number of functions that are analyzed");
+STATISTIC(NumEligibleFunctions, "Number of functions that are eligible");
+
+/// Returns true if the \opIdx operand of \p CI is the callee operand.
+static bool isCalleeOperand(const CallBase *CI, unsigned OpIdx) {
+ return &CI->getCalledOperandUse() == &CI->getOperandUse(OpIdx);
+}
+
+static bool canParameterizeCallOperand(const CallBase *CI, unsigned OpIdx) {
+ if (CI->isInlineAsm())
+ return false;
+ Function *Callee = CI->getCalledOperand()
+ ? dyn_cast_or_null<Function>(
+ CI->getCalledOperand()->stripPointerCasts())
+ : nullptr;
+ if (Callee) {
+ if (Callee->isIntrinsic())
+ return false;
+ // objc_msgSend stubs must be called, and can't have their address taken.
+ if (Callee->getName().starts_with("objc_msgSend$"))
+ return false;
+ }
+ if (isCalleeOperand(CI, OpIdx) &&
+ CI->getOperandBundle(LLVMContext::OB_ptrauth).has_value()) {
+ // The operand is the callee and it has already been signed. Ignore this
+ // because we cannot add another ptrauth bundle to the call instruction.
+ return false;
+ }
+ return true;
+}
+
+bool isEligibleInstrunctionForConstantSharing(const Instruction *I) {
+ switch (I->getOpcode()) {
+ case Instruction::Load:
+ case Instruction::Store:
+ case Instruction::Call:
+ case Instruction::Invoke:
+ return true;
+ default:
+ return false;
+ }
+}
+
+bool isEligibleOperandForConstantSharing(const Instruction *I, unsigned OpIdx) {
+ assert(OpIdx < I->getNumOperands() && "Invalid operand index");
+
+ if (!isEligibleInstrunctionForConstantSharing(I))
+ return false;
+
+ auto Opnd = I->getOperand(OpIdx);
+ if (!isa<Constant>(Opnd))
+ return false;
+
+ if (const auto *CI = dyn_cast<CallBase>(I))
+ return canParameterizeCallOperand(CI, OpIdx);
+
+ return true;
+}
+
+/// Returns true if function \p F is eligible for merging.
+bool isEligibleFunction(Function *F) {
+ if (F->isDeclaration())
+ return false;
+
+ if (F->hasFnAttribute(llvm::Attribute::NoMerge))
+ return false;
+
+ if (F->hasAvailableExternallyLinkage()) {
+ return false;
+ }
+
+ if (F->getFunctionType()->isVarArg()) {
+ return false;
+ }
+
+ if (F->getCallingConv() == CallingConv::SwiftTail)
+ return false;
+
+ // if function contains callsites with musttail, if we merge
+ // it, the merged function will have the musttail callsite, but
+ // the number of parameters can change, thus the parameter count
+ // of the callsite will mismatch with the function itself.
+ // if (IgnoreMusttailFunction) {
+ for (const BasicBlock &BB : *F) {
+ for (const Instruction &I : BB) {
+ const auto *CB = dyn_cast<CallBase>(&I);
+ if (CB && CB->isMustTailCall())
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static bool
+isEligibleInstrunctionForConstantSharingLocal(const Instruction *I) {
+ switch (I->getOpcode()) {
+ case Instruction::Load:
+ case Instruction::Store:
+ case Instruction::Call:
+ case Instruction::Invoke:
+ return true;
+ default:
+ return false;
+ }
+}
+
+static bool ignoreOp(const Instruction *I, unsigned OpIdx) {
+ assert(OpIdx < I->getNumOperands() && "Invalid operand index");
+
+ if (!isEligibleInstrunctionForConstantSharingLocal(I))
+ return false;
+
+ if (!isa<Constant>(I->getOperand(OpIdx)))
+ return false;
+
+ if (const auto *CI = dyn_cast<CallBase>(I))
+ return canParameterizeCallOperand(CI, OpIdx);
+
+ return true;
+}
+
+// copy from merge functions.cpp
+static Value *createCast(IRBuilder<> &Builder, Value *V, Type *DestTy) {
+ Type *SrcTy = V->getType();
+ if (SrcTy->isStructTy()) {
+ assert(DestTy->isStructTy());
+ assert(SrcTy->getStructNumElements() == DestTy->getStructNumElements());
+ Value *Result = PoisonValue::get(DestTy);
+ for (unsigned int I = 0, E = SrcTy->getStructNumElements(); I < E; ++I) {
+ Value *Element =
+ createCast(Builder, Builder.CreateExtractValue(V, ArrayRef(I)),
+ DestTy->getStructElementType(I));
+
+ Result = Builder.CreateInsertValue(Result, Element, ArrayRef(I));
+ }
+ return Result;
+ }
+ assert(!DestTy->isStructTy());
+ if (auto *SrcAT = dyn_cast<ArrayType>(SrcTy)) {
+ auto *DestAT = dyn_cast<ArrayType>(DestTy);
+ assert(DestAT);
+ assert(SrcAT->getNumElements() == DestAT->getNumElements());
+ Value *Result = UndefValue::get(DestTy);
+ for (unsigned int I = 0, E = SrcAT->getNumElements(); I < E; ++I) {
+ Value *Element =
+ createCast(Builder, Builder.CreateExtractValue(V, ArrayRef(I)),
+ DestAT->getElementType());
+
+ Result = Builder.CreateInsertValue(Result, Element, ArrayRef(I));
+ }
+ return Result;
+ }
+ assert(!DestTy->isArrayTy());
+ if (SrcTy->isIntegerTy() && DestTy->isPointerTy())
+ return Builder.CreateIntToPtr(V, DestTy);
+ else if (SrcTy->isPointerTy() && DestTy->isIntegerTy())
+ return Builder.CreatePtrToInt(V, DestTy);
+ else
+ return Builder.CreateBitCast(V, DestTy);
+}
+
+void GlobalMergeFunc::analyze(Module &M) {
+ ++NumAnalyzedModues;
+ for (Function &Func : M) {
+ ++NumAnalyzedFunctions;
+ if (isEligibleFunction(&Func)) {
+ ++NumEligibleFunctions;
+
+ auto FI = llvm::StructuralHashWithDifferences(Func, ignoreOp);
+
+ // Convert the map to a vector for a serialization-friendly format.
+ IndexOperandHashVecType IndexOperandHashes;
+ for (auto &Pair : *FI.IndexOperandHashMap)
+ IndexOperandHashes.emplace_back(Pair);
+
+ StableFunction SF(FI.FunctionHash, get_stable_name(Func.getName()).str(),
+ M.getModuleIdentifier(), FI.IndexInstruction->size(),
+ std::move(IndexOperandHashes));
+
+ LocalFunctionMap->insert(SF);
+ }
+ }
+}
+
+/// Tuple to hold function info to process merging.
+struct FuncMergeInfo {
+ StableFunctionMap::StableFunctionEntry *SF;
+ Function *F;
+ std::unique_ptr<IndexInstrMap> IndexInstruction;
+};
+
+// Given the func info, and the parameterized locations, create and return
+// a new merged function by replacing the original constants with the new
+// parameters.
+static Function *createMergedFunction(FuncMergeInfo &FI,
+ ArrayRef<Type *> ConstParamTypes,
+ const ParamLocsVecTy &ParamLocsVec) {
+ // Synthesize a new merged function name by appending ".Tgm" to the root
+ // function's name.
+ auto *MergedFunc = FI.F;
+ auto NewFunctionName = MergedFunc->getName().str() + ".Tgm";
+ auto *M = MergedFunc->getParent();
+ assert(!M->getFunction(NewFunctionName));
+
+ FunctionType *OrigTy = MergedFunc->getFunctionType();
+ // Get the original params' types.
+ SmallVector<Type *> ParamTypes(OrigTy->param_begin(), OrigTy->param_end());
+ // Append const parameter types that are passed in.
+ ParamTypes.append(ConstParamTypes.begin(), ConstParamTypes.end());
+ FunctionType *FuncType =
+ FunctionType::get(OrigTy->getReturnType(), ParamTypes, false);
+
+ // Declare a new function
+ Function *NewFunction =
+ Function::Create(FuncType, MergedFunc->getLinkage(), NewFunctionName);
+ if (auto *SP = MergedFunc->getSubprogram())
+ NewFunction->setSubprogram(SP);
+ NewFunction->copyAttributesFrom(MergedFunc);
+ NewFunction->setDLLStorageClass(GlobalValue::DefaultStorageClass);
+
+ NewFunction->setLinkage(GlobalValue::InternalLinkage);
+ NewFunction->addFnAttr(Attribute::NoInline);
+
+ // Add the new function before the root function.
+ M->getFunctionList().insert(MergedFunc->getIterator(), NewFunction);
+
+ // Move the body of MergedFunc into the NewFunction.
+ NewFunction->splice(NewFunction->begin(), MergedFunc);
+
+ // Update the original args by the new args.
+ auto NewArgIter = NewFunction->arg_begin();
+ for (Argument &OrigArg : MergedFunc->args()) {
+ Argument &NewArg = *NewArgIter++;
+ OrigArg.replaceAllUsesWith(&NewArg);
+ }
+
+ // Replace the original Constants by the new args.
+ unsigned NumOrigArgs = MergedFunc->arg_size();
+ for (unsigned ParamIdx = 0; ParamIdx < ParamLocsVec.size(); ++ParamIdx) {
+ Argument *NewArg = NewFunction->getArg(NumOrigArgs + ParamIdx);
+ for (auto [InstIndex, OpndIndex] : ParamLocsVec[ParamIdx]) {
+ auto *Inst = FI.IndexInstruction->lookup(InstIndex);
+ auto *OrigC = Inst->getOperand(OpndIndex);
+ if (OrigC->getType() != NewArg->getType()) {
+ IRBuilder<> Builder(Inst->getParent(), Inst->getIterator());
+ Inst->setOperand(OpndIndex,
+ createCast(Builder, NewArg, OrigC->getType()));
+ } else
+ Inst->setOperand(OpndIndex, NewArg);
+ }
+ }
+
+ return NewFunction;
+}
+
+// Given the original function (Thunk) and the merged function (ToFunc), create
+// a thunk to the merged function.
+
+static void createThunk(FuncMergeInfo &FI, ArrayRef<Constant *> Params,
+ Function *ToFunc) {
+ auto *Thunk = FI.F;
+
+ assert(Thunk->arg_size() + Params.size() ==
+ ToFunc->getFunctionType()->getNumParams());
+ Thunk->dropAllReferences();
+
+ BasicBlock *BB = BasicBlock::Create(Thunk->getContext(), "", Thunk);
+ IRBuilder<> Builder(BB);
+
+ SmallVector<Value *> Args;
+ unsigned ParamIdx = 0;
+ FunctionType *ToFuncTy = ToFunc->getFunctionType();
+
+ // Add arguments which are passed through Thunk.
+ for (Argument &AI : Thunk->args()) {
+ Args.push_back(createCast(Builder, &AI, ToFuncTy->getParamType(ParamIdx)));
+ ++ParamIdx;
+ }
+
+ // Add new arguments defined by Params.
+ for (auto *Param : Params) {
+ assert(ParamIdx < ToFuncTy->getNumParams());
+ // FIXME: do not support signing
+ Args.push_back(
+ createCast(Builder, Param, ToFuncTy->getParamType(ParamIdx)));
+ ++ParamIdx;
+ }
+
+ CallInst *CI = Builder.CreateCall(ToFunc, Args);
+ bool isSwiftTailCall = ToFunc->getCallingConv() == CallingConv::SwiftTail &&
+ Thunk->getCallingConv() == CallingConv::SwiftTail;
+ CI->setTailCallKind(isSwiftTailCall ? llvm::CallInst::TCK_MustTail
+ : llvm::CallInst::TCK_Tail);
+ CI->setCallingConv(ToFunc->getCallingConv());
+ CI->setAttributes(ToFunc->getAttributes());
+ if (Thunk->getReturnType()->isVoidTy())
+ Builder.CreateRetVoid();
+ else
+ Builder.CreateRet(createCast(Builder, CI, Thunk->getReturnType()));
+}
+
+// Check if the old merged/optimized IndexOperandHashMap is compatible with
+// the current IndexOperandHashMap. An operand hash may not be stable across
+// different builds due to varying modules combined. To address this, we relax
+// the hash check condition by comparing Const hash patterns instead of absolute
+// hash values. For example, let's assume we have three Consts located at idx1,
+// idx3, and idx6, where their corresponding hashes are hash1, hash2, and hash1
+// in the old merged map below:
+// Old (Merged): [(idx1, hash1), (idx3, hash2), (idx6, hash1)]
+// Current: [(idx1, hash1'), (idx3, hash2'), (idx6, hash1')]
+// If the current function also has three Consts in the same locations,
+// with hash sequences hash1', hash2', and hash1' where the first and third
+// are the same as the old hash sequences, we consider them matched.
+static bool checkConstHashCompatible(
+ const DenseMap<IndexPair, stable_hash> &OldInstOpndIndexToConstHash,
+ const DenseMap<IndexPair, stable_hash> &CurrInstOpndIndexToConstHash) {
+
+ DenseMap<stable_hash, stable_hash> OldHashToCurrHash;
+ for (const auto &[Index, OldHash] : OldInstOpndIndexToConstHash) {
+ auto It = CurrInstOpndIndexToConstHash.find(Index);
+ if (It == CurrInstOpndIndexToConstHash.end())
+ return false;
+
+ auto CurrHash = It->second;
+ auto J = OldHashToCurrHash.find(OldHash);
+ if (J == OldHashToCurrHash.end())
+ OldHashToCurrHash.insert({OldHash, CurrHash});
+ else if (J->second != CurrHash)
+ return false;
+ }
+
+ return true;
+}
+
+// Validate the locations pointed by a param has the same hash and Constant.
+static bool
+checkConstLocationCompatible(const StableFunctionMap::StableFunctionEntry &SF,
+ const IndexInstrMap &IndexInstruction,
+ const ParamLocsVecTy &ParamLocsVec) {
+ for (auto &ParamLocs : ParamLocsVec) {
+ std::optional<stable_hash> OldHash;
+ std::optional<Constant *> OldConst;
+ for (auto &Loc : ParamLocs) {
+ assert(SF.IndexOperandHashMap->count(Loc));
+ auto CurrHash = SF.IndexOperandHashMap.get()->at(Loc);
+ auto [InstIndex, OpndIndex] = Loc;
+ assert(InstIndex < IndexInstruction.size());
+ const auto *Inst = IndexInstruction.lookup(InstIndex);
+ auto *CurrConst = cast<Constant>(Inst->getOperand(OpndIndex));
+ if (!OldHash) {
+ OldHash = CurrHash;
+ OldConst = CurrConst;
+ } else if (CurrConst != *OldConst || CurrHash != *OldHash)
+ return false;
+ }
+ }
+ return true;
+}
+
+static ParamLocsVecTy computeParamInfo(
+ const SmallVector<std::unique_ptr<StableFunctionMap::StableFunctionEntry>>
+ &SFS) {
+ std::map<std::vector<stable_hash>, ParamLocs> HashSeqToLocs;
+ auto &RSF = *SFS[0];
+ unsigned StableFunctionCount = SFS.size();
+
+ for (auto &[IndexPair, Hash] : *RSF.IndexOperandHashMap) {
+ // Const hash sequence across stable functions.
+ // We will allocate a parameter per unique hash squence.
+ // can't use SmallVector as key
+ std::vector<stable_hash> ConstHashSeq;
+ ConstHashSeq.push_back(Hash);
+ bool Identical = true;
+ for (unsigned J = 1; J < StableFunctionCount; ++J) {
+ auto &SF = SFS[J];
+ assert(SF->IndexOperandHashMap->count(IndexPair));
+ auto SHash = (*SF->IndexOperandHashMap)[IndexPair];
+ if (Hash != SHash)
+ Identical = false;
+ ConstHashSeq.push_back(SHash);
+ }
+
+ if (Identical)
+ continue;
+
+ // For each unique Const hash sequence (parameter), add the locations.
+ HashSeqToLocs[ConstHashSeq].push_back(IndexPair);
+ }
+
+ ParamLocsVecTy ParamLocsVec;
+ for (auto &[HashSeq, Locs] : HashSeqToLocs) {
+ ParamLocsVec.push_back(std::move(Locs));
+ std::sort(
+ ParamLocsVec.begin(), ParamLocsVec.end(),
+ [&](const ParamLocs &L, const ParamLocs &R) { return L[0] < R[0]; });
+ }
+ return ParamLocsVec;
+}
+
+static bool isProfitable(
+ const SmallVector<std::unique_ptr<StableFunctionMap::StableFunctionEntry>>
+ &SFS,
+ const Function *F) {
+ // No interest if the number of candidates are less than 2.
+ unsigned StableFunctionCount = SFS.size();
+ if (StableFunctionCount < 2)
+ return false;
+
+ unsigned InstCount = SFS[0]->InstCount;
+ if (InstCount < GlobalMergingMinInstrs)
+ return false;
+
+ unsigned ParamCount = SFS[0]->IndexOperandHashMap->size();
+ unsigned TotalParamCount = ParamCount + F->getFunctionType()->getNumParams();
+ if (TotalParamCount > GlobalMergingMaxParams)
+ return false;
+
+ unsigned Benefit = InstCount * (StableFunctionCount - 1);
+ unsigned Cost =
+ (GlobalMergingParamOverhead * ParamCount + GlobalMergingCallOverhead) *
+ StableFunctionCount +
+ GlobalMergingExtraThreshold;
+
+ bool Result = Benefit > Cost;
+ LLVM_DEBUG(dbgs() << "isProfitable: Function = " << F->getName() << ", "
+ << "StableFunctionCount = " << StableFunctionCount
+ << ", InstCount = " << InstCount
+ << ", ParamCount = " << ParamCount
+ << ", Benefit = " << Benefit << ", Cost = " << Cost
+ << ", Result = " << (Result ? "true" : "false") << "\n");
+ return Result;
+}
+
+bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
+ bool Changed = false;
+
+ // Build a map from stable function name to function.
+ StringMap<Function *> StableNameToFuncMap;
+ for (auto &F : M)
+ StableNameToFuncMap[get_stable_name(F.getName())] = &F;
+ // Track merged functions
+ DenseSet<Function *> MergedFunctions;
+
+ auto ModId = M.getModuleIdentifier();
+ for (auto &[Hash, SFS] : FunctionMap->getFunctionMap()) {
+ // Compute the parameter locations based on the unique hash sequences
+ // across the candidates.
+ auto ParamLocsVec = computeParamInfo(SFS);
+ LLVM_DEBUG({
+ dbgs() << "[GlobalMergeFunc] Merging hash: " << Hash << " with Params "
+ << ParamLocsVec.size() << "\n";
+ });
+
+ Function *MergedFunc = nullptr;
+ std::string MergedModId;
+ SmallVector<FuncMergeInfo> FuncMergeInfos;
+ for (auto &SF : SFS) {
+ // Get the function from the stable name.
+ auto I = StableNameToFuncMap.find(
+ *FunctionMap->getNameForId(SF->FunctionNameId));
+ if (I == StableNameToFuncMap.end())
+ continue;
+ Function *F = I->second;
+ assert(F);
+ // Skip if the function has been merged before.
+ if (MergedFunctions.count(F))
+ continue;
+ // Consider the function if it is eligible for merging.
+ if (!isEligibleFunction(F))
+ continue;
+
+ auto FI = llvm::StructuralHashWithDifferences(*F, ignoreOp);
+ uint64_t FuncHash = FI.FunctionHash;
+ if (Hash != FuncHash) {
+ ++NumMismatchedFunctionHashGlobalMergeFunction;
+ continue;
+ }
+
+ if (SF->InstCount != FI.IndexInstruction->size()) {
+ ++NumMismatchedInstCountGlobalMergeFunction;
+ continue;
+ }
+ bool HasValidSharedConst = true;
+ for (auto &[Index, Hash] : *SF->IndexOperandHashMap) {
+ auto [InstIndex, OpndIndex] = Index;
+ assert(InstIndex < FI.IndexInstruction->size());
+ auto *Inst = FI.IndexInstruction->lookup(InstIndex);
+ if (!isEligibleOperandForConstantSharing(Inst, OpndIndex)) {
+ HasValidSharedConst = false;
+ break;
+ }
+ }
+ if (!HasValidSharedConst) {
+ ++NumMismatchedConstHashGlobalMergeFunction;
+ continue;
+ }
+ if (!checkConstHashCompatible(*SF->IndexOperandHashMap,
+ *FI.IndexOperandHashMap)) {
+ ++NumMismatchedConstHashGlobalMergeFunction;
+ continue;
+ }
+ if (!checkConstLocationCompatible(*SF, *FI.IndexInstruction,
+ ParamLocsVec)) {
+ ++NumMismatchedConstHashGlobalMergeFunction;
+ continue;
+ }
+
+ if (!isProfitable(SFS, F))
+ break;
+
+ if (MergedFunc) {
+ // Check if the matched functions fall into the same (first) module.
+ // This module check is not strictly necessary as the functions can move
+ // around. We just want to avoid merging functions from different
+ // modules than the first one in the functon map, as they may not end up
+ // with not being ICFed.
+ if (MergedModId != *FunctionMap->getNameForId(SF->ModuleNameId)) {
+ ++NumMismatchedModuleIdGlobalMergeFunction;
+ continue;
+ }
+ } else {
+ MergedFunc = F;
+ MergedModId = *FunctionMap->getNameForId(SF->ModuleNameId);
+ }
+
+ FuncMergeInfos.push_back({SF.get(), F, std::move(FI.IndexInstruction)});
+ MergedFunctions.insert(F);
+ }
+ unsigned FuncMergeInfoSize = FuncMergeInfos.size();
+ if (FuncMergeInfoSize == 0)
+ continue;
+
+ LLVM_DEBUG({
+ dbgs() << "[GlobalMergeFunc] Merging function count " << FuncMergeInfoSize
+ << " in " << ModId << "\n";
+ });
+ for (auto &FMI : FuncMergeInfos) {
+ Changed = true;
+
+ // We've already validated all locations of constant operands pointed by
+ // the parameters. Just use the first one to bookkeep the original
+ // constants for each parameter
+ SmallVector<Constant *> Params;
+ SmallVector<Type *> ParamTypes;
+ for (auto &ParamLocs : ParamLocsVec) {
+ assert(!ParamLocs.empty());
+ auto &[InstIndex, OpndIndex] = ParamLocs[0];
+ auto *Inst = FMI.IndexInstruction->lookup(InstIndex);
+ auto *Opnd = cast<Constant>(Inst->getOperand(OpndIndex));
+ Params.push_back(Opnd);
+ ParamTypes.push_back(Opnd->getType());
+ }
+
+ // Create a merged function derived from the first function in the current
+ // module context.
+ Function *MergedFunc =
+ createMergedFunction(FMI, ParamTypes, ParamLocsVec);
+
+ LLVM_DEBUG({
+ dbgs() << "[GlobalMergeFunc] Merged function (hash:" << FMI.SF->Hash
+ << ") " << MergedFunc->getName() << " generated from "
+ << FMI.F->getName() << ":\n";
+ MergedFunc->dump();
+ });
+
+ // Create a thunk to the merged function.
+ createThunk(FMI, Params, MergedFunc);
+ LLVM_DEBUG({
+ dbgs() << "[GlobalMergeFunc] Thunk generated: \n";
+ FMI.F->dump();
+ });
+ ++NumGlobalMergeFunctions;
+ }
+ }
+
+ return Changed;
+}
+
+char GlobalMergeFunc::ID = 0;
+INITIALIZE_PASS_BEGIN(GlobalMergeFunc, "global-merge-func",
+ "Global merge function pass", false, false)
+INITIALIZE_PASS_END(GlobalMergeFunc, "global-merge-func",
+ "Global merge function pass", false, false)
+
+StringRef GlobalMergeFunc::getPassName() const {
+ return "Global Merge Functions";
+}
+
+void GlobalMergeFunc::getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addUsedIfAvailable<ImmutableModuleSummaryIndexWrapperPass>();
+ AU.setPreservesAll();
+ ModulePass::getAnalysisUsage(AU);
+}
+
+GlobalMergeFunc::GlobalMergeFunc() : ModulePass(ID) {
+ initializeGlobalMergeFuncPass(*llvm::PassRegistry::getPassRegistry());
+}
+
+namespace llvm {
+Pass *createGlobalMergeFuncPass() { return new GlobalMergeFunc(); }
+} // namespace llvm
+
+void GlobalMergeFunc::initializeMergerMode(const Module &M) {
+ LocalFunctionMap = std::make_unique<StableFunctionMap>();
+
+ if (DisableGlobalMerging)
+ return;
+
+ if (auto *IndexWrapperPass =
+ getAnalysisIfAvailable<ImmutableModuleSummaryIndexWrapperPass>()) {
+ auto *TheIndex = IndexWrapperPass->getIndex();
+ // (Full)LTO module does not have functions added to the index.
+ // In this case, we run a local merger without using codegen data.
+ if (TheIndex && !TheIndex->hasExportedFunctions(M))
+ return;
+ }
+
+ if (cgdata::emitCGData())
+ MergerMode = HashFunctionMode::BuildingHashFuncion;
+ else if (cgdata::hasStableFunctionMap())
+ MergerMode = HashFunctionMode::UsingHashFunction;
+}
+
+void GlobalMergeFunc::emitFunctionMap(Module &M) {
+ LLVM_DEBUG({
+ dbgs() << "Emit function map. Size: " << LocalFunctionMap->size() << "\n";
+ });
+ // No need to emit the function map if it is empty.
+ if (LocalFunctionMap->empty())
+ return;
+ SmallVector<char> Buf;
+ raw_svector_ostream OS(Buf);
+
+ StableFunctionMapRecord::serialize(OS, LocalFunctionMap.get());
+
+ std::unique_ptr<MemoryBuffer> Buffer = MemoryBuffer::getMemBuffer(
+ OS.str(), "in-memory stable function map", false);
+
+ Triple TT(M.getTargetTriple());
+ embedBufferInModule(M, *Buffer.get(),
+ getCodeGenDataSectionName(CG_merge, TT.getObjectFormat()),
+ Align(4));
+}
+
+bool GlobalMergeFunc::runOnModule(Module &M) {
+ initializeMergerMode(M);
+
+ const StableFunctionMap *FuncMap;
+ if (MergerMode == HashFunctionMode::UsingHashFunction) {
+ // Use the prior CG data to optimistically create global merge candidates.
+ FuncMap = cgdata::getStableFunctionMap();
+ } else {
+ analyze(M);
+ // Emit the local function map to the custom section, __llvm_merge before
+ // finalizing it.
+ if (MergerMode == HashFunctionMode::BuildingHashFuncion)
+ emitFunctionMap(M);
+ LocalFunctionMap->finalize();
+ FuncMap = LocalFunctionMap.get();
+ }
+
+ return merge(M, FuncMap);
+}
diff --git a/llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll b/llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll
new file mode 100644
index 00000000000000..4f5f5c0b5b26d9
--- /dev/null
+++ b/llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll
@@ -0,0 +1,62 @@
+; This test checks if two similar functions, f1 and f2, can be merged locally within a single module
+; while parameterizing a difference in their global variables, g1 and g2.
+; To achieve this, we create two instances of the global merging function, f1.Tgm and f2.Tgm,
+; which are tail-called from thunks g1 and g2 respectively.
+; These identical functions, f1.Tgm and f2.Tgm, will be folded by the linker via Identical Code Folding (IFC).
+
+; RUN: opt -module-summary -module-hash %s -o %t
+
+; RUN: llvm-lto2 run -enable-global-merge-func=false %t -o %tout-nomerge \
+; RUN: -r %t,_f1,px \
+; RUN: -r %t,_f2,px \
+; RUN: -r %t,_g,l -r %t,_g1,l -r %t,_g2,l
+; RUN: llvm-nm %tout-nomerge.1 | FileCheck %s --check-prefix=NOMERGE
+; RUN: llvm-lto2 run -enable-global-merge-func=true %t -o %tout-merge \
+; RUN: -r %t,_f1,px \
+; RUN: -r %t,_f2,px \
+; RUN: -r %t,_g,l -r %t,_g1,l -r %t,_g2,l
+; RUN: llvm-nm %tout-merge.1 | FileCheck %s --check-prefix=GLOBALMERGE
+; RUN: llvm-objdump -d %tout-merge.1 | FileCheck %s --check-prefix=THUNK
+
+; NOMERGE-NOT: _f1.Tgm
+; GLOBALMERGE: _f1.Tgm
+; GLOBALMERGE: _f2.Tgm
+
+; THUNK: <_f1>:
+; THUNK-NEXT: adrp x1,
+; THUNK-NEXT: ldr x1, [x1]
+; THUNK-NEXT: b
+
+; THUNK: <_f2>:
+; THUNK-NEXT: adrp x1,
+; THUNK-NEXT: ldr x1, [x1]
+; THUNK-NEXT: b
+
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-unknown-ios12.0.0"
+
+ at g = external local_unnamed_addr global [0 x i32], align 4
+ at g1 = external global i32, align 4
+ at g2 = external global i32, align 4
+
+define i32 @f1(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g1, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
+
+define i32 @f2(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g2, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
diff --git a/llvm/test/ThinLTO/AArch64/cgdata-merge-read.ll b/llvm/test/ThinLTO/AArch64/cgdata-merge-read.ll
new file mode 100644
index 00000000000000..da756e7f15e68e
--- /dev/null
+++ b/llvm/test/ThinLTO/AArch64/cgdata-merge-read.ll
@@ -0,0 +1,82 @@
+; This test demonstrates how similar functions are handled during global outlining.
+; Currently, we do not attempt to share an merged function for identical sequences.
+; Instead, each merging instance is created uniquely.
+
+; RUN: rm -rf %t; split-file %s %t
+
+; RUN: opt -module-summary -module-hash %t/foo.ll -o %t-foo.bc
+; RUN: opt -module-summary -module-hash %t/goo.ll -o %t-goo.bc
+
+; First, run with -codegen-data-generate=true to generate the cgdata in the object files.
+; Using llvm-cgdata, merge the cg data.
+; RUN: llvm-lto2 run -enable-global-merge-func=true -codegen-data-generate=true %t-foo.bc %t-goo.bc -o %tout-write \
+; RUN: -r %t-foo.bc,_f1,px \
+; RUN: -r %t-goo.bc,_f2,px \
+; RUN: -r %t-foo.bc,_g,l -r %t-foo.bc,_g1,l -r %t-foo.bc,_g2,l \
+; RUN: -r %t-goo.bc,_g,l -r %t-goo.bc,_g1,l -r %t-goo.bc,_g2,l
+; RUN: llvm-cgdata --merge -o %tout.cgdata %tout-write.1 %tout-write.2
+
+; Now run with -codegen-data-use-path=%tout.cgdata to optimize the binary.
+; Each module has its own merging instance as it is matched against the merged cgdata.
+; RUN: llvm-lto2 run -enable-global-merge-func=true \
+; RUN: -codegen-data-use-path=%tout.cgdata \
+; RUN: %t-foo.bc %t-goo.bc -o %tout-read \
+; RUN: -r %t-foo.bc,_f1,px \
+; RUN: -r %t-goo.bc,_f2,px \
+; RUN: -r %t-foo.bc,_g,l -r %t-foo.bc,_g1,l -r %t-foo.bc,_g2,l \
+; RUN: -r %t-goo.bc,_g,l -r %t-goo.bc,_g1,l -r %t-goo.bc,_g2,l
+; RUN: llvm-nm %tout-read.1 | FileCheck %s --check-prefix=READ1
+; RUN: llvm-nm %tout-read.2 | FileCheck %s --check-prefix=READ2
+; RUN: llvm-objdump -d %tout-read.1 | FileCheck %s --check-prefix=THUNK1
+; RUN: llvm-objdump -d %tout-read.2 | FileCheck %s --check-prefix=THUNK2
+
+; READ1: _f1.Tgm
+; READ2: _f2.Tgm
+
+; THUNK1: <_f1>:
+; THUNK1-NEXT: adrp x1,
+; THUNK1-NEXT: ldr x1, [x1]
+; THUNK1-NEXT: b
+
+; THUNK2: <_f2>:
+; THUNK2-NEXT: adrp x1,
+; THUNK2-NEXT: ldr x1, [x1]
+; THUNK2-NEXT: b
+
+;--- foo.ll
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-unknown-ios12.0.0"
+
+ at g = external local_unnamed_addr global [0 x i32], align 4
+ at g1 = external global i32, align 4
+ at g2 = external global i32, align 4
+
+define i32 @f1(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g1, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
+
+;--- goo.ll
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-unknown-ios12.0.0"
+
+ at g = external local_unnamed_addr global [0 x i32], align 4
+ at g1 = external global i32, align 4
+ at g2 = external global i32, align 4
+
+define i32 @f2(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g2, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
diff --git a/llvm/test/ThinLTO/AArch64/cgdata-merge-two-rounds.ll b/llvm/test/ThinLTO/AArch64/cgdata-merge-two-rounds.ll
new file mode 100644
index 00000000000000..06880e3d268189
--- /dev/null
+++ b/llvm/test/ThinLTO/AArch64/cgdata-merge-two-rounds.ll
@@ -0,0 +1,68 @@
+; TODO: This test checks if the how similar functions are handled during global outlining
+; by repeating the codegen via -codegen-data-thinlto-two-rounds=true.
+
+; RUN: rm -rf %t; split-file %s %t
+
+; RUN: opt -module-summary -module-hash %t/foo.ll -o %t-foo.bc
+; RUN: opt -module-summary -module-hash %t/goo.ll -o %t-goo.bc
+
+; RUN: llvm-lto2 run -enable-global-merge-func=true -codegen-data-thinlto-two-rounds=true %t-foo.bc %t-goo.bc -o %tout \
+; RUN: -r %t-foo.bc,_f1,px \
+; RUN: -r %t-goo.bc,_f2,px \
+; RUN: -r %t-foo.bc,_g,l -r %t-foo.bc,_g1,l -r %t-foo.bc,_g2,l \
+; RUN: -r %t-goo.bc,_g,l -r %t-goo.bc,_g1,l -r %t-goo.bc,_g2,l
+; RUN: llvm-nm %tout.1 | FileCheck %s --check-prefix=OUT1
+; RUN: llvm-nm %tout.2 | FileCheck %s --check-prefix=OUT2
+; RUN: llvm-objdump -d %tout.1 | FileCheck %s --check-prefix=THUNK1
+; RUN: llvm-objdump -d %tout.2 | FileCheck %s --check-prefix=THUNK2
+
+; OUT1: _f1.Tgm
+; OUT2: _f2.Tgm
+
+; THUNK1: <_f1>:
+; THUNK1-NEXT: adrp x1,
+; THUNK1-NEXT: ldr x1, [x1]
+; THUNK1-NEXT: b
+
+; THUNK2: <_f2>:
+; THUNK2-NEXT: adrp x1,
+; THUNK2-NEXT: ldr x1, [x1]
+; THUNK2-NEXT: b
+
+;--- foo.ll
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-unknown-ios12.0.0"
+
+ at g = external local_unnamed_addr global [0 x i32], align 4
+ at g1 = external global i32, align 4
+ at g2 = external global i32, align 4
+
+define i32 @f1(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g1, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
+
+;--- goo.ll
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-unknown-ios12.0.0"
+
+ at g = external local_unnamed_addr global [0 x i32], align 4
+ at g1 = external global i32, align 4
+ at g2 = external global i32, align 4
+
+define i32 @f2(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g2, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
diff --git a/llvm/test/ThinLTO/AArch64/cgdata-merge-write.ll b/llvm/test/ThinLTO/AArch64/cgdata-merge-write.ll
new file mode 100644
index 00000000000000..a4022eb885b43f
--- /dev/null
+++ b/llvm/test/ThinLTO/AArch64/cgdata-merge-write.ll
@@ -0,0 +1,97 @@
+; This test verifies whether a stable function is encoded into the __llvm_merge section
+; when the -codegen-data-generate flag is used under -enable-global-merge-func=true.
+
+; RUN: rm -rf %t; split-file %s %t
+
+; RUN: opt -module-summary -module-hash %t/foo.ll -o %t-foo.bc
+; RUN: opt -module-summary -module-hash %t/goo.ll -o %t-goo.bc
+
+; RUN: llvm-lto2 run -enable-global-merge-func=true -codegen-data-generate=false %t-foo.bc %t-goo.bc -o %tout-nowrite \
+; RUN: -r %t-foo.bc,_f1,px \
+; RUN: -r %t-goo.bc,_f2,px \
+; RUN: -r %t-foo.bc,_g,l -r %t-foo.bc,_g1,l -r %t-foo.bc,_g2,l \
+; RUN: -r %t-goo.bc,_g,l -r %t-goo.bc,_g1,l -r %t-goo.bc,_g2,l
+; RUN: llvm-nm %tout-nowrite.1 | FileCheck %s --check-prefix=NOWRITE
+; RUN: llvm-nm %tout-nowrite.2 | FileCheck %s --check-prefix=NOWRITE
+
+; No merge instance is locally created as each module has a singltone function.
+; NOWRITE-NOT: _f1.Tgm
+; NOWRITE-NOT: _f2.Tgm
+
+; RUN: llvm-lto2 run -enable-global-merge-func=true -codegen-data-generate=true %t-foo.bc %t-goo.bc -o %tout-nowrite \
+; RUN: -r %t-foo.bc,_f1,px \
+; RUN: -r %t-goo.bc,_f2,px \
+; RUN: -r %t-foo.bc,_g,l -r %t-foo.bc,_g1,l -r %t-foo.bc,_g2,l \
+; RUN: -r %t-goo.bc,_g,l -r %t-goo.bc,_g1,l -r %t-goo.bc,_g2,l
+; RUN: llvm-nm %tout-nowrite.1 | FileCheck %s --check-prefix=WRITE
+; RUN: llvm-nm %tout-nowrite.2 | FileCheck %s --check-prefix=WRITE
+; RUN: llvm-objdump -h %tout-nowrite.1 | FileCheck %s --check-prefix=SECTNAME
+; RUN: llvm-objdump -h %tout-nowrite.2 | FileCheck %s --check-prefix=SECTNAME
+
+; On a write mode, no merging happens yet for each module.
+; We only create stable functions and publish them into __llvm_merge section for each object.
+; WRITE-NOT: _f1.Tgm
+; WRITE-NOT: _f2.Tgm
+; SECTNAME: __llvm_merge
+
+; Merge the cgdata using llvm-cgdata.
+; We now validate the content of the merged cgdata.
+; Two functions have the same hash with only one different constnat at a same location.
+; RUN: llvm-cgdata --merge -o %tout.cgdata %tout-nowrite.1 %tout-nowrite.2
+; RUN: llvm-cgdata --convert %tout.cgdata -o - | FileCheck %s
+
+; CHECK: - Hash: [[#%d,HASH:]]
+; CHECK-NEXT: FunctionName: f1
+; CHECK-NEXT: ModuleName: {{.*}}
+; CHECK-NEXT: InstCount: [[#%d,INSTCOUNT:]]
+; CHECK-NEXT: IndexOperandHashes:
+; CHECK-NEXT: - InstIndex: [[#%d,INSTINDEX:]]
+; CHECK-NEXT: OpndIndex: [[#%d,OPNDINDEX:]]
+; CHECK-NEXT: OpndHash: {{.*}}
+
+; CHECK: - Hash: [[#%d,HASH]]
+; CHECK-NEXT: FunctionName: f2
+; CHECK-NEXT: ModuleName: {{.*}}
+; CHECK-NEXT: InstCount: [[#%d,INSTCOUNT]]
+; CHECK-NEXT: IndexOperandHashes:
+; CHECK-NEXT: - InstIndex: [[#%d,INSTINDEX]]
+; CHECK-NEXT: OpndIndex: [[#%d,OPNDINDEX]]
+; CHECK-NEXT: OpndHash: {{.*}}
+
+;--- foo.ll
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-unknown-ios12.0.0"
+
+ at g = external local_unnamed_addr global [0 x i32], align 4
+ at g1 = external global i32, align 4
+ at g2 = external global i32, align 4
+
+define i32 @f1(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g1, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
+
+;--- goo.ll
+target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
+target triple = "arm64-unknown-ios12.0.0"
+
+ at g = external local_unnamed_addr global [0 x i32], align 4
+ at g1 = external global i32, align 4
+ at g2 = external global i32, align 4
+
+define i32 @f2(i32 %a) {
+entry:
+ %idxprom = sext i32 %a to i64
+ %arrayidx = getelementptr inbounds [0 x i32], [0 x i32]* @g, i64 0, i64 %idxprom
+ %0 = load i32, i32* %arrayidx, align 4
+ %1 = load volatile i32, i32* @g2, align 4
+ %mul = mul nsw i32 %1, %0
+ %add = add nsw i32 %mul, 1
+ ret i32 %add
+}
diff --git a/llvm/tools/llvm-lto2/CMakeLists.txt b/llvm/tools/llvm-lto2/CMakeLists.txt
index 3b4644d6e27715..6ddccc7f17442f 100644
--- a/llvm/tools/llvm-lto2/CMakeLists.txt
+++ b/llvm/tools/llvm-lto2/CMakeLists.txt
@@ -6,6 +6,7 @@ set(LLVM_LINK_COMPONENTS
BitReader
CodeGen
Core
+ IPO
Linker
LTO
MC
diff --git a/llvm/tools/llvm-lto2/llvm-lto2.cpp b/llvm/tools/llvm-lto2/llvm-lto2.cpp
index d4f022ef021a44..0dc6623552a4bd 100644
--- a/llvm/tools/llvm-lto2/llvm-lto2.cpp
+++ b/llvm/tools/llvm-lto2/llvm-lto2.cpp
@@ -28,6 +28,7 @@
#include "llvm/Support/PluginLoader.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/Threading.h"
+#include "llvm/Transforms/IPO.h"
#include <atomic>
using namespace llvm;
@@ -195,6 +196,7 @@ static cl::opt<bool> TryUseNewDbgInfoFormat(
extern cl::opt<bool> UseNewDbgInfoFormat;
extern cl::opt<cl::boolOrDefault> LoadBitcodeIntoNewDbgInfoFormat;
extern cl::opt<cl::boolOrDefault> PreserveInputDbgFormat;
+extern cl::opt<bool> EnableGlobalMergeFunc;
static void check(Error E, std::string Msg) {
if (!E)
@@ -374,6 +376,10 @@ static int run(int argc, char **argv) {
if (DI.getSeverity() == DS_Error)
HasErrors = true;
};
+ Conf.PreCodeGenPassesHook = [](legacy::PassManager &pm) {
+ if (EnableGlobalMergeFunc)
+ pm.add(createGlobalMergeFuncPass());
+ };
LTO::LTOKind LTOMode = LTO::LTOK_Default;
>From e86d78bfa0961a1de88569e18ef5707aeaf680ea Mon Sep 17 00:00:00 2001
From: Kyungwoo Lee <kyulee at meta.com>
Date: Fri, 18 Oct 2024 10:12:21 -0700
Subject: [PATCH 2/7] Address comments from tschuett
---
llvm/include/llvm/Transforms/IPO.h | 3 ++
.../Transforms/IPO/GlobalMergeFunctions.h | 45 ++++++++--------
.../Transforms/IPO/GlobalMergeFunctions.cpp | 53 +++++++++----------
3 files changed, 51 insertions(+), 50 deletions(-)
diff --git a/llvm/include/llvm/Transforms/IPO.h b/llvm/include/llvm/Transforms/IPO.h
index 86a8654f56997c..28cf330ad20812 100644
--- a/llvm/include/llvm/Transforms/IPO.h
+++ b/llvm/include/llvm/Transforms/IPO.h
@@ -55,6 +55,9 @@ enum class PassSummaryAction {
Export, ///< Export information to summary.
};
+/// createGlobalMergeFuncPass - This pass generates merged instances by
+/// parameterizing distinct constants across similar functions, utilizing stable
+/// function hash information.
Pass *createGlobalMergeFuncPass();
} // End llvm namespace
diff --git a/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h b/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
index 565be54f89e882..395aeda73b2d0f 100644
--- a/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
+++ b/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
@@ -5,23 +5,29 @@
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
-///
-/// This file defines global merge functions pass and related data structure.
-///
+//
+// This pass defines the implementation of a function merging mechanism
+// that utilizes a stable function hash to track differences in constants and
+// identify potential merge candidates. The process involves two rounds:
+// 1. The first round collects stable function hashes and identifies merge
+// candidates with matching hashes. It also computes the set of parameters
+// that point to different constants during the stable function merge.
+// 2. The second round leverages this collected global function information to
+// optimistically create a merged function in each module context, ensuring
+// correct transformation.
+// Similar to the global outliner, this approach uses the linker's deduplication
+// (ICF) to fold identical merged functions, thereby reducing the final binary
+// size. The work is inspired by the concepts discussed in the following paper:
+// https://dl.acm.org/doi/pdf/10.1145/3652032.3657575.
+//
//===----------------------------------------------------------------------===//
-#ifndef PIKA_TRANSFORMS_UTILS_GLOBALMERGEFUNCTIONS_H
-#define PIKA_TRANSFORMS_UTILS_GLOBALMERGEFUNCTIONS_H
+#ifndef LLVM_TRANSFORMS_IPO_GLOBALMERGEFUNCTIONS_H
+#define LLVM_TRANSFORMS_IPO_GLOBALMERGEFUNCTIONS_H
-#include "llvm/ADT/DenseMap.h"
-#include "llvm/ADT/StableHashing.h"
-#include "llvm/ADT/StringRef.h"
#include "llvm/CGData/StableFunctionMap.h"
-#include "llvm/IR/Instructions.h"
#include "llvm/IR/Module.h"
#include "llvm/Pass.h"
-#include <map>
-#include <mutex>
enum class HashFunctionMode {
Local,
@@ -36,15 +42,10 @@ namespace llvm {
using ParamLocs = SmallVector<IndexPair, 4>;
// A vector of parameters
using ParamLocsVecTy = SmallVector<ParamLocs, 8>;
-// A map of stable hash to a vector of stable functions
-
-/// GlobalMergeFunc finds functions which only differ by constants in
-/// certain instructions, e.g. resulting from specialized functions of layout
-/// compatible types.
-/// Unlike PikaMergeFunc that directly compares IRs, this uses stable function
-/// hash to find the merge candidate. Similar to the global outliner, we can run
-/// codegen twice to collect function merge candidate in the first round, and
-/// merge functions globally in the second round.
+
+/// GlobalMergeFunc is a ModulePass that implements a function merging mechanism
+/// using stable function hashes. It identifies and merges functions with
+/// matching hashes across modules to optimize binary size.
class GlobalMergeFunc : public ModulePass {
HashFunctionMode MergerMode = HashFunctionMode::Local;
@@ -69,9 +70,9 @@ class GlobalMergeFunc : public ModulePass {
/// Emit LocalFunctionMap into __llvm_merge section.
void emitFunctionMap(Module &M);
- /// Merge functions in the module using the global function map.
+ /// Merge functions in the module using the given function map.
bool merge(Module &M, const StableFunctionMap *FunctionMap);
};
} // end namespace llvm
-#endif // PIKA_TRANSFORMS_UTILS_GLOBALMERGEFUNCTIONS_H
+#endif // LLVM_TRANSFORMS_IPO_GLOBALMERGEFUNCTIONS_H
diff --git a/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp b/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
index 6fd1a66b5a197c..5a52c8f3304186 100644
--- a/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
@@ -6,16 +6,19 @@
//
//===----------------------------------------------------------------------===//
//
-// TODO: This implements a function merge using function hash while tracking
-// differences in Constants. This uses stable function hash to find potential
-// merge candidates. The first codegen round collects stable function hashes,
-// and determines the merge candidates that match the stable function hashes.
-// The set of parameters pointing to different Constants are also computed
-// during the stable function merge. The second codegen round uses this global
-// function info to optimistically create a merged function in each module
-// context to guarantee correct transformation. Similar to the global outliner,
-// the linker's deduplication (ICF) folds the identical merged functions to save
-// the final binary size.
+// This pass defines the implementation of a function merging mechanism
+// that utilizes a stable function hash to track differences in constants and
+// create potential merge candidates. The process involves two rounds:
+// 1. The first round collects stable function hashes and identifies merge
+// candidates with matching hashes. It also computes the set of parameters
+// that point to different constants during the stable function merge.
+// 2. The second round leverages this collected global function information to
+// optimistically create a merged function in each module context, ensuring
+// correct transformation.
+// Similar to the global outliner, this approach uses the linker's deduplication
+// (ICF) to fold identical merged functions, thereby reducing the final binary
+// size. The work is inspired by the concepts discussed in the following paper:
+// https://dl.acm.org/doi/pdf/10.1145/3652032.3657575.
//
//===----------------------------------------------------------------------===//
@@ -23,9 +26,6 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ModuleSummaryAnalysis.h"
#include "llvm/CGData/CodeGenData.h"
-#include "llvm/CGData/StableFunctionMap.h"
-#include "llvm/CodeGen/MachineStableHash.h"
-#include "llvm/CodeGen/Passes.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/StructuralHash.h"
#include "llvm/InitializePasses.h"
@@ -84,7 +84,7 @@ STATISTIC(NumAnalyzedModues, "Number of modules that are analyzed");
STATISTIC(NumAnalyzedFunctions, "Number of functions that are analyzed");
STATISTIC(NumEligibleFunctions, "Number of functions that are eligible");
-/// Returns true if the \opIdx operand of \p CI is the callee operand.
+/// Returns true if the \OpIdx operand of \p CI is the callee operand.
static bool isCalleeOperand(const CallBase *CI, unsigned OpIdx) {
return &CI->getCalledOperandUse() == &CI->getOperandUse(OpIdx);
}
@@ -148,22 +148,19 @@ bool isEligibleFunction(Function *F) {
if (F->hasFnAttribute(llvm::Attribute::NoMerge))
return false;
- if (F->hasAvailableExternallyLinkage()) {
+ if (F->hasAvailableExternallyLinkage())
return false;
- }
- if (F->getFunctionType()->isVarArg()) {
+ if (F->getFunctionType()->isVarArg())
return false;
- }
if (F->getCallingConv() == CallingConv::SwiftTail)
return false;
- // if function contains callsites with musttail, if we merge
+ // If function contains callsites with musttail, if we merge
// it, the merged function will have the musttail callsite, but
// the number of parameters can change, thus the parameter count
// of the callsite will mismatch with the function itself.
- // if (IgnoreMusttailFunction) {
for (const BasicBlock &BB : *F) {
for (const Instruction &I : BB) {
const auto *CB = dyn_cast<CallBase>(&I);
@@ -203,7 +200,6 @@ static bool ignoreOp(const Instruction *I, unsigned OpIdx) {
return true;
}
-// copy from merge functions.cpp
static Value *createCast(IRBuilder<> &Builder, Value *V, Type *DestTy) {
Type *SrcTy = V->getType();
if (SrcTy->isStructTy()) {
@@ -252,7 +248,8 @@ void GlobalMergeFunc::analyze(Module &M) {
auto FI = llvm::StructuralHashWithDifferences(Func, ignoreOp);
- // Convert the map to a vector for a serialization-friendly format.
+ // Convert the operand map to a vector for a serialization-friendly
+ // format.
IndexOperandHashVecType IndexOperandHashes;
for (auto &Pair : *FI.IndexOperandHashMap)
IndexOperandHashes.emplace_back(Pair);
@@ -597,7 +594,7 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
// This module check is not strictly necessary as the functions can move
// around. We just want to avoid merging functions from different
// modules than the first one in the functon map, as they may not end up
- // with not being ICFed.
+ // with not being ICFed by the linker.
if (MergedModId != *FunctionMap->getNameForId(SF->ModuleNameId)) {
++NumMismatchedModuleIdGlobalMergeFunction;
continue;
@@ -618,12 +615,12 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
dbgs() << "[GlobalMergeFunc] Merging function count " << FuncMergeInfoSize
<< " in " << ModId << "\n";
});
+
for (auto &FMI : FuncMergeInfos) {
Changed = true;
// We've already validated all locations of constant operands pointed by
- // the parameters. Just use the first one to bookkeep the original
- // constants for each parameter
+ // the parameters. Populate parameters pointing to the original constants.
SmallVector<Constant *> Params;
SmallVector<Type *> ParamTypes;
for (auto &ParamLocs : ParamLocsVec) {
@@ -635,8 +632,7 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
ParamTypes.push_back(Opnd->getType());
}
- // Create a merged function derived from the first function in the current
- // module context.
+ // Create a merged function derived from the current function.
Function *MergedFunc =
createMergedFunction(FMI, ParamTypes, ParamLocsVec);
@@ -647,7 +643,8 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
MergedFunc->dump();
});
- // Create a thunk to the merged function.
+ // Transform the current function into a thunk that calls the merged
+ // function.
createThunk(FMI, Params, MergedFunc);
LLVM_DEBUG({
dbgs() << "[GlobalMergeFunc] Thunk generated: \n";
>From ac87d92b8bcbb187f24908d0b993c4c39dfb435b Mon Sep 17 00:00:00 2001
From: Kyungwoo Lee <kyulee at meta.com>
Date: Sat, 9 Nov 2024 17:27:02 -0800
Subject: [PATCH 3/7] address comments from ellishg
---
.../Transforms/IPO/GlobalMergeFunctions.h | 5 +
.../Transforms/IPO/GlobalMergeFunctions.cpp | 126 ++++++------------
2 files changed, 47 insertions(+), 84 deletions(-)
diff --git a/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h b/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
index 395aeda73b2d0f..bf2ca6c8977580 100644
--- a/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
+++ b/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
@@ -54,6 +54,11 @@ class GlobalMergeFunc : public ModulePass {
public:
static char ID;
+ /// The suffix used to identify the merged function that parameterizes
+ /// the constant values. Note that the original function, without this suffix,
+ /// becomes a thunk supplying contexts to the merged function via parameters.
+ static constexpr const char MergingInstanceSuffix[] = ".Tgm";
+
GlobalMergeFunc();
StringRef getPassName() const override;
diff --git a/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp b/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
index 5a52c8f3304186..bae5c5b3c8193f 100644
--- a/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
@@ -6,19 +6,7 @@
//
//===----------------------------------------------------------------------===//
//
-// This pass defines the implementation of a function merging mechanism
-// that utilizes a stable function hash to track differences in constants and
-// create potential merge candidates. The process involves two rounds:
-// 1. The first round collects stable function hashes and identifies merge
-// candidates with matching hashes. It also computes the set of parameters
-// that point to different constants during the stable function merge.
-// 2. The second round leverages this collected global function information to
-// optimistically create a merged function in each module context, ensuring
-// correct transformation.
-// Similar to the global outliner, this approach uses the linker's deduplication
-// (ICF) to fold identical merged functions, thereby reducing the final binary
-// size. The work is inspired by the concepts discussed in the following paper:
-// https://dl.acm.org/doi/pdf/10.1145/3652032.3657575.
+// This pass implements the global merge function pass.
//
//===----------------------------------------------------------------------===//
@@ -70,15 +58,15 @@ static cl::opt<unsigned> GlobalMergingExtraThreshold(
extern cl::opt<bool> EnableGlobalMergeFunc;
-STATISTIC(NumMismatchedFunctionHashGlobalMergeFunction,
+STATISTIC(NumMismatchedFunctionHash,
"Number of mismatched function hash for global merge function");
-STATISTIC(NumMismatchedInstCountGlobalMergeFunction,
+STATISTIC(NumMismatchedInstCount,
"Number of mismatched instruction count for global merge function");
-STATISTIC(NumMismatchedConstHashGlobalMergeFunction,
+STATISTIC(NumMismatchedConstHash,
"Number of mismatched const hash for global merge function");
-STATISTIC(NumMismatchedModuleIdGlobalMergeFunction,
+STATISTIC(NumMismatchedModuleId,
"Number of mismatched Module Id for global merge function");
-STATISTIC(NumGlobalMergeFunctions,
+STATISTIC(NumMergedFunctions,
"Number of functions that are actually merged using function hash");
STATISTIC(NumAnalyzedModues, "Number of modules that are analyzed");
STATISTIC(NumAnalyzedFunctions, "Number of functions that are analyzed");
@@ -112,34 +100,6 @@ static bool canParameterizeCallOperand(const CallBase *CI, unsigned OpIdx) {
return true;
}
-bool isEligibleInstrunctionForConstantSharing(const Instruction *I) {
- switch (I->getOpcode()) {
- case Instruction::Load:
- case Instruction::Store:
- case Instruction::Call:
- case Instruction::Invoke:
- return true;
- default:
- return false;
- }
-}
-
-bool isEligibleOperandForConstantSharing(const Instruction *I, unsigned OpIdx) {
- assert(OpIdx < I->getNumOperands() && "Invalid operand index");
-
- if (!isEligibleInstrunctionForConstantSharing(I))
- return false;
-
- auto Opnd = I->getOperand(OpIdx);
- if (!isa<Constant>(Opnd))
- return false;
-
- if (const auto *CI = dyn_cast<CallBase>(I))
- return canParameterizeCallOperand(CI, OpIdx);
-
- return true;
-}
-
/// Returns true if function \p F is eligible for merging.
bool isEligibleFunction(Function *F) {
if (F->isDeclaration())
@@ -172,8 +132,7 @@ bool isEligibleFunction(Function *F) {
return true;
}
-static bool
-isEligibleInstrunctionForConstantSharingLocal(const Instruction *I) {
+static bool isEligibleInstrunctionForConstantSharing(const Instruction *I) {
switch (I->getOpcode()) {
case Instruction::Load:
case Instruction::Store:
@@ -188,7 +147,7 @@ isEligibleInstrunctionForConstantSharingLocal(const Instruction *I) {
static bool ignoreOp(const Instruction *I, unsigned OpIdx) {
assert(OpIdx < I->getNumOperands() && "Invalid operand index");
- if (!isEligibleInstrunctionForConstantSharingLocal(I))
+ if (!isEligibleInstrunctionForConstantSharing(I))
return false;
if (!isa<Constant>(I->getOperand(OpIdx)))
@@ -233,10 +192,9 @@ static Value *createCast(IRBuilder<> &Builder, Value *V, Type *DestTy) {
assert(!DestTy->isArrayTy());
if (SrcTy->isIntegerTy() && DestTy->isPointerTy())
return Builder.CreateIntToPtr(V, DestTy);
- else if (SrcTy->isPointerTy() && DestTy->isIntegerTy())
+ if (SrcTy->isPointerTy() && DestTy->isIntegerTy())
return Builder.CreatePtrToInt(V, DestTy);
- else
- return Builder.CreateBitCast(V, DestTy);
+ return Builder.CreateBitCast(V, DestTy);
}
void GlobalMergeFunc::analyze(Module &M) {
@@ -268,6 +226,9 @@ struct FuncMergeInfo {
StableFunctionMap::StableFunctionEntry *SF;
Function *F;
std::unique_ptr<IndexInstrMap> IndexInstruction;
+ FuncMergeInfo(StableFunctionMap::StableFunctionEntry *SF, Function *F,
+ std::unique_ptr<IndexInstrMap> IndexInstruction)
+ : SF(SF), F(F), IndexInstruction(std::move(IndexInstruction)) {}
};
// Given the func info, and the parameterized locations, create and return
@@ -279,7 +240,8 @@ static Function *createMergedFunction(FuncMergeInfo &FI,
// Synthesize a new merged function name by appending ".Tgm" to the root
// function's name.
auto *MergedFunc = FI.F;
- auto NewFunctionName = MergedFunc->getName().str() + ".Tgm";
+ std::string NewFunctionName =
+ MergedFunc->getName().str() + GlobalMergeFunc::MergingInstanceSuffix;
auto *M = MergedFunc->getParent();
assert(!M->getFunction(NewFunctionName));
@@ -288,8 +250,8 @@ static Function *createMergedFunction(FuncMergeInfo &FI,
SmallVector<Type *> ParamTypes(OrigTy->param_begin(), OrigTy->param_end());
// Append const parameter types that are passed in.
ParamTypes.append(ConstParamTypes.begin(), ConstParamTypes.end());
- FunctionType *FuncType =
- FunctionType::get(OrigTy->getReturnType(), ParamTypes, false);
+ FunctionType *FuncType = FunctionType::get(OrigTy->getReturnType(),
+ ParamTypes, /*isVarArg=*/false);
// Declare a new function
Function *NewFunction =
@@ -326,8 +288,9 @@ static Function *createMergedFunction(FuncMergeInfo &FI,
IRBuilder<> Builder(Inst->getParent(), Inst->getIterator());
Inst->setOperand(OpndIndex,
createCast(Builder, NewArg, OrigC->getType()));
- } else
+ } else {
Inst->setOperand(OpndIndex, NewArg);
+ }
}
}
@@ -336,7 +299,6 @@ static Function *createMergedFunction(FuncMergeInfo &FI,
// Given the original function (Thunk) and the merged function (ToFunc), create
// a thunk to the merged function.
-
static void createThunk(FuncMergeInfo &FI, ArrayRef<Constant *> Params,
Function *ToFunc) {
auto *Thunk = FI.F;
@@ -361,7 +323,6 @@ static void createThunk(FuncMergeInfo &FI, ArrayRef<Constant *> Params,
// Add new arguments defined by Params.
for (auto *Param : Params) {
assert(ParamIdx < ToFuncTy->getNumParams());
- // FIXME: do not support signing
Args.push_back(
createCast(Builder, Param, ToFuncTy->getParamType(ParamIdx)));
++ParamIdx;
@@ -431,8 +392,9 @@ checkConstLocationCompatible(const StableFunctionMap::StableFunctionEntry &SF,
if (!OldHash) {
OldHash = CurrHash;
OldConst = CurrConst;
- } else if (CurrConst != *OldConst || CurrHash != *OldHash)
+ } else if (CurrConst != *OldConst || CurrHash != *OldHash) {
return false;
+ }
}
}
return true;
@@ -454,8 +416,7 @@ static ParamLocsVecTy computeParamInfo(
bool Identical = true;
for (unsigned J = 1; J < StableFunctionCount; ++J) {
auto &SF = SFS[J];
- assert(SF->IndexOperandHashMap->count(IndexPair));
- auto SHash = (*SF->IndexOperandHashMap)[IndexPair];
+ auto SHash = SF->IndexOperandHashMap->at(IndexPair);
if (Hash != SHash)
Identical = false;
ConstHashSeq.push_back(SHash);
@@ -471,9 +432,9 @@ static ParamLocsVecTy computeParamInfo(
ParamLocsVecTy ParamLocsVec;
for (auto &[HashSeq, Locs] : HashSeqToLocs) {
ParamLocsVec.push_back(std::move(Locs));
- std::sort(
- ParamLocsVec.begin(), ParamLocsVec.end(),
- [&](const ParamLocs &L, const ParamLocs &R) { return L[0] < R[0]; });
+ llvm::sort(ParamLocsVec, [&](const ParamLocs &L, const ParamLocs &R) {
+ return L[0] < R[0];
+ });
}
return ParamLocsVec;
}
@@ -527,10 +488,8 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
// Compute the parameter locations based on the unique hash sequences
// across the candidates.
auto ParamLocsVec = computeParamInfo(SFS);
- LLVM_DEBUG({
- dbgs() << "[GlobalMergeFunc] Merging hash: " << Hash << " with Params "
- << ParamLocsVec.size() << "\n";
- });
+ LLVM_DEBUG(dbgs() << "[GlobalMergeFunc] Merging hash: " << Hash
+ << " with Params " << ParamLocsVec.size() << "\n");
Function *MergedFunc = nullptr;
std::string MergedModId;
@@ -553,12 +512,12 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
auto FI = llvm::StructuralHashWithDifferences(*F, ignoreOp);
uint64_t FuncHash = FI.FunctionHash;
if (Hash != FuncHash) {
- ++NumMismatchedFunctionHashGlobalMergeFunction;
+ ++NumMismatchedFunctionHash;
continue;
}
if (SF->InstCount != FI.IndexInstruction->size()) {
- ++NumMismatchedInstCountGlobalMergeFunction;
+ ++NumMismatchedInstCount;
continue;
}
bool HasValidSharedConst = true;
@@ -566,23 +525,23 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
auto [InstIndex, OpndIndex] = Index;
assert(InstIndex < FI.IndexInstruction->size());
auto *Inst = FI.IndexInstruction->lookup(InstIndex);
- if (!isEligibleOperandForConstantSharing(Inst, OpndIndex)) {
+ if (!ignoreOp(Inst, OpndIndex)) {
HasValidSharedConst = false;
break;
}
}
if (!HasValidSharedConst) {
- ++NumMismatchedConstHashGlobalMergeFunction;
+ ++NumMismatchedConstHash;
continue;
}
if (!checkConstHashCompatible(*SF->IndexOperandHashMap,
*FI.IndexOperandHashMap)) {
- ++NumMismatchedConstHashGlobalMergeFunction;
+ ++NumMismatchedConstHash;
continue;
}
if (!checkConstLocationCompatible(*SF, *FI.IndexInstruction,
ParamLocsVec)) {
- ++NumMismatchedConstHashGlobalMergeFunction;
+ ++NumMismatchedConstHash;
continue;
}
@@ -596,7 +555,7 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
// modules than the first one in the functon map, as they may not end up
// with not being ICFed by the linker.
if (MergedModId != *FunctionMap->getNameForId(SF->ModuleNameId)) {
- ++NumMismatchedModuleIdGlobalMergeFunction;
+ ++NumMismatchedModuleId;
continue;
}
} else {
@@ -604,17 +563,15 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
MergedModId = *FunctionMap->getNameForId(SF->ModuleNameId);
}
- FuncMergeInfos.push_back({SF.get(), F, std::move(FI.IndexInstruction)});
+ FuncMergeInfos.emplace_back(SF.get(), F, std::move(FI.IndexInstruction));
MergedFunctions.insert(F);
}
unsigned FuncMergeInfoSize = FuncMergeInfos.size();
if (FuncMergeInfoSize == 0)
continue;
- LLVM_DEBUG({
- dbgs() << "[GlobalMergeFunc] Merging function count " << FuncMergeInfoSize
- << " in " << ModId << "\n";
- });
+ LLVM_DEBUG(dbgs() << "[GlobalMergeFunc] Merging function count "
+ << FuncMergeInfoSize << " in " << ModId << "\n");
for (auto &FMI : FuncMergeInfos) {
Changed = true;
@@ -650,7 +607,7 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
dbgs() << "[GlobalMergeFunc] Thunk generated: \n";
FMI.F->dump();
});
- ++NumGlobalMergeFunctions;
+ ++NumMergedFunctions;
}
}
@@ -682,8 +639,10 @@ Pass *createGlobalMergeFuncPass() { return new GlobalMergeFunc(); }
} // namespace llvm
void GlobalMergeFunc::initializeMergerMode(const Module &M) {
+ // Initialize the local function map regardless of the merger mode.
LocalFunctionMap = std::make_unique<StableFunctionMap>();
+ // Skip the global merge mode. The local merge is still enabled.
if (DisableGlobalMerging)
return;
@@ -703,9 +662,8 @@ void GlobalMergeFunc::initializeMergerMode(const Module &M) {
}
void GlobalMergeFunc::emitFunctionMap(Module &M) {
- LLVM_DEBUG({
- dbgs() << "Emit function map. Size: " << LocalFunctionMap->size() << "\n";
- });
+ LLVM_DEBUG(dbgs() << "Emit function map. Size: " << LocalFunctionMap->size()
+ << "\n");
// No need to emit the function map if it is empty.
if (LocalFunctionMap->empty())
return;
>From 1d2436e3c578ccf2e06fa708eef23c6dae75412d Mon Sep 17 00:00:00 2001
From: Kyungwoo Lee <kyulee at meta.com>
Date: Sat, 9 Nov 2024 23:47:09 -0800
Subject: [PATCH 4/7] Address comments from nocchijiang
---
.../IPO => CodeGen}/GlobalMergeFunctions.h | 26 +++--
llvm/include/llvm/CodeGen/Passes.h | 3 +
llvm/include/llvm/InitializePasses.h | 2 +-
llvm/include/llvm/Passes/CodeGenPassBuilder.h | 4 +
.../llvm/Passes/MachinePassRegistry.def | 1 +
.../include/llvm/Target/CGPassBuilderOption.h | 1 +
llvm/include/llvm/Transforms/IPO.h | 5 -
llvm/lib/CodeGen/CMakeLists.txt | 1 +
.../IPO => CodeGen}/GlobalMergeFunctions.cpp | 110 +++++++++++-------
llvm/lib/CodeGen/TargetPassConfig.cpp | 4 +
llvm/lib/LTO/LTO.cpp | 1 -
llvm/lib/Passes/PassBuilder.cpp | 1 +
llvm/lib/Passes/PassBuilderPipelines.cpp | 1 +
llvm/lib/Passes/PassRegistry.def | 1 +
llvm/lib/Transforms/IPO/CMakeLists.txt | 2 -
.../ThinLTO/AArch64/cgdata-merge-local.ll | 65 +++++++----
llvm/tools/llvm-lto2/CMakeLists.txt | 1 -
llvm/tools/llvm-lto2/llvm-lto2.cpp | 6 -
18 files changed, 142 insertions(+), 93 deletions(-)
rename llvm/include/llvm/{Transforms/IPO => CodeGen}/GlobalMergeFunctions.h (84%)
rename llvm/lib/{Transforms/IPO => CodeGen}/GlobalMergeFunctions.cpp (92%)
diff --git a/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h b/llvm/include/llvm/CodeGen/GlobalMergeFunctions.h
similarity index 84%
rename from llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
rename to llvm/include/llvm/CodeGen/GlobalMergeFunctions.h
index bf2ca6c8977580..982a66270f616e 100644
--- a/llvm/include/llvm/Transforms/IPO/GlobalMergeFunctions.h
+++ b/llvm/include/llvm/CodeGen/GlobalMergeFunctions.h
@@ -22,11 +22,12 @@
//
//===----------------------------------------------------------------------===//
-#ifndef LLVM_TRANSFORMS_IPO_GLOBALMERGEFUNCTIONS_H
-#define LLVM_TRANSFORMS_IPO_GLOBALMERGEFUNCTIONS_H
+#ifndef LLVM_CODEGEN_GLOBALMERGEFUNCTIONS_H
+#define LLVM_CODEGEN_GLOBALMERGEFUNCTIONS_H
#include "llvm/CGData/StableFunctionMap.h"
#include "llvm/IR/Module.h"
+#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
enum class HashFunctionMode {
@@ -46,28 +47,24 @@ using ParamLocsVecTy = SmallVector<ParamLocs, 8>;
/// GlobalMergeFunc is a ModulePass that implements a function merging mechanism
/// using stable function hashes. It identifies and merges functions with
/// matching hashes across modules to optimize binary size.
-class GlobalMergeFunc : public ModulePass {
+class GlobalMergeFunc {
HashFunctionMode MergerMode = HashFunctionMode::Local;
std::unique_ptr<StableFunctionMap> LocalFunctionMap;
-public:
- static char ID;
+ const ModuleSummaryIndex *Index;
+public:
/// The suffix used to identify the merged function that parameterizes
/// the constant values. Note that the original function, without this suffix,
/// becomes a thunk supplying contexts to the merged function via parameters.
static constexpr const char MergingInstanceSuffix[] = ".Tgm";
- GlobalMergeFunc();
-
- StringRef getPassName() const override;
-
- void getAnalysisUsage(AnalysisUsage &AU) const override;
+ GlobalMergeFunc(const ModuleSummaryIndex *Index) : Index(Index){};
void initializeMergerMode(const Module &M);
- bool runOnModule(Module &M) override;
+ bool run(Module &M);
/// Analyze module to create stable function into LocalFunctionMap.
void analyze(Module &M);
@@ -79,5 +76,10 @@ class GlobalMergeFunc : public ModulePass {
bool merge(Module &M, const StableFunctionMap *FunctionMap);
};
+/// Global function merging pass for new pass manager.
+struct GlobalMergeFuncPass : public PassInfoMixin<GlobalMergeFuncPass> {
+ PreservedAnalyses run(Module &M, AnalysisManager<Module> &);
+};
+
} // end namespace llvm
-#endif // LLVM_TRANSFORMS_IPO_GLOBALMERGEFUNCTIONS_H
+#endif // LLVM_CODEGEN_GLOBALMERGEFUNCTIONS_H
diff --git a/llvm/include/llvm/CodeGen/Passes.h b/llvm/include/llvm/CodeGen/Passes.h
index 72054ab1d3c21a..708ff464b38093 100644
--- a/llvm/include/llvm/CodeGen/Passes.h
+++ b/llvm/include/llvm/CodeGen/Passes.h
@@ -507,6 +507,9 @@ namespace llvm {
/// This pass frees the memory occupied by the MachineFunction.
FunctionPass *createFreeMachineFunctionPass();
+ /// This pass performs merging similar functions globally.
+ ModulePass *createGlobalMergeFuncPass();
+
/// This pass performs outlining on machine instructions directly before
/// printing assembly.
ModulePass *createMachineOutlinerPass(bool RunOnAllFunctions = true);
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index a43a96e90543cc..b27ecd8cdcb8c1 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -123,7 +123,7 @@ void initializeGCEmptyBasicBlocksPass(PassRegistry &);
void initializeGCMachineCodeAnalysisPass(PassRegistry &);
void initializeGCModuleInfoPass(PassRegistry &);
void initializeGVNLegacyPassPass(PassRegistry &);
-void initializeGlobalMergeFuncPass(PassRegistry &);
+void initializeGlobalMergeFuncPassWrapperPass(PassRegistry &);
void initializeGlobalMergePass(PassRegistry &);
void initializeGlobalsAAWrapperPassPass(PassRegistry &);
void initializeHardwareLoopsLegacyPass(PassRegistry &);
diff --git a/llvm/include/llvm/Passes/CodeGenPassBuilder.h b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
index 9e95625fd1d881..3f7d226c7cbffb 100644
--- a/llvm/include/llvm/Passes/CodeGenPassBuilder.h
+++ b/llvm/include/llvm/Passes/CodeGenPassBuilder.h
@@ -35,6 +35,7 @@
#include "llvm/CodeGen/FinalizeISel.h"
#include "llvm/CodeGen/GCMetadata.h"
#include "llvm/CodeGen/GlobalMerge.h"
+#include "llvm/CodeGen/GlobalMergeFunctions.h"
#include "llvm/CodeGen/IndirectBrExpand.h"
#include "llvm/CodeGen/InterleavedAccess.h"
#include "llvm/CodeGen/InterleavedLoadCombine.h"
@@ -713,6 +714,9 @@ void CodeGenPassBuilder<Derived, TargetMachineT>::addIRPasses(
// Convert conditional moves to conditional jumps when profitable.
if (getOptLevel() != CodeGenOptLevel::None && !Opt.DisableSelectOptimize)
addPass(SelectOptimizePass(&TM));
+
+ if (Opt.EnableGlobalMergeFunc)
+ addPass(GlobalMergeFuncPass());
}
/// Turn exception handling constructs into something the code generators can
diff --git a/llvm/include/llvm/Passes/MachinePassRegistry.def b/llvm/include/llvm/Passes/MachinePassRegistry.def
index 9d12a120ff7ac6..3ceb5ca7d18eda 100644
--- a/llvm/include/llvm/Passes/MachinePassRegistry.def
+++ b/llvm/include/llvm/Passes/MachinePassRegistry.def
@@ -29,6 +29,7 @@ MODULE_PASS("jmc-instrumenter", JMCInstrumenterPass())
MODULE_PASS("lower-emutls", LowerEmuTLSPass())
MODULE_PASS("pre-isel-intrinsic-lowering", PreISelIntrinsicLoweringPass())
MODULE_PASS("shadow-stack-gc-lowering", ShadowStackGCLoweringPass())
+MODULE_PASS("global-merge-func", GlobalMergeFuncPass())
#undef MODULE_PASS
#ifndef FUNCTION_ANALYSIS
diff --git a/llvm/include/llvm/Target/CGPassBuilderOption.h b/llvm/include/llvm/Target/CGPassBuilderOption.h
index 8ab6d63a00056a..29bdb9c1746d3c 100644
--- a/llvm/include/llvm/Target/CGPassBuilderOption.h
+++ b/llvm/include/llvm/Target/CGPassBuilderOption.h
@@ -31,6 +31,7 @@ struct CGPassBuilderOption {
bool DisableVerify = false;
bool EnableImplicitNullChecks = false;
bool EnableBlockPlacementStats = false;
+ bool EnableGlobalMergeFunc = false;
bool EnableMachineFunctionSplitter = false;
bool MISchedPostRA = false;
bool EarlyLiveIntervals = false;
diff --git a/llvm/include/llvm/Transforms/IPO.h b/llvm/include/llvm/Transforms/IPO.h
index 28cf330ad20812..ee0e35aa618325 100644
--- a/llvm/include/llvm/Transforms/IPO.h
+++ b/llvm/include/llvm/Transforms/IPO.h
@@ -55,11 +55,6 @@ enum class PassSummaryAction {
Export, ///< Export information to summary.
};
-/// createGlobalMergeFuncPass - This pass generates merged instances by
-/// parameterizing distinct constants across similar functions, utilizing stable
-/// function hash information.
-Pass *createGlobalMergeFuncPass();
-
} // End llvm namespace
#endif
diff --git a/llvm/lib/CodeGen/CMakeLists.txt b/llvm/lib/CodeGen/CMakeLists.txt
index 5a17944db0ae03..5f0496a013795d 100644
--- a/llvm/lib/CodeGen/CMakeLists.txt
+++ b/llvm/lib/CodeGen/CMakeLists.txt
@@ -71,6 +71,7 @@ add_llvm_component_library(LLVMCodeGen
GCMetadataPrinter.cpp
GCRootLowering.cpp
GlobalMerge.cpp
+ GlobalMergeFunctions.cpp
HardwareLoops.cpp
IfConversion.cpp
ImplicitNullChecks.cpp
diff --git a/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
similarity index 92%
rename from llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
rename to llvm/lib/CodeGen/GlobalMergeFunctions.cpp
index bae5c5b3c8193f..46b4ea76b655ff 100644
--- a/llvm/lib/Transforms/IPO/GlobalMergeFunctions.cpp
+++ b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
@@ -10,7 +10,7 @@
//
//===----------------------------------------------------------------------===//
-#include "llvm/Transforms/IPO/GlobalMergeFunctions.h"
+#include "llvm/CodeGen/GlobalMergeFunctions.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/ModuleSummaryAnalysis.h"
#include "llvm/CGData/CodeGenData.h"
@@ -56,8 +56,6 @@ static cl::opt<unsigned> GlobalMergingExtraThreshold(
"to be considered beneficial."),
cl::init(0), cl::Hidden);
-extern cl::opt<bool> EnableGlobalMergeFunc;
-
STATISTIC(NumMismatchedFunctionHash,
"Number of mismatched function hash for global merge function");
STATISTIC(NumMismatchedInstCount,
@@ -87,8 +85,12 @@ static bool canParameterizeCallOperand(const CallBase *CI, unsigned OpIdx) {
if (Callee) {
if (Callee->isIntrinsic())
return false;
+ auto Name = Callee->getName();
// objc_msgSend stubs must be called, and can't have their address taken.
- if (Callee->getName().starts_with("objc_msgSend$"))
+ if (Name.starts_with("objc_msgSend$"))
+ return false;
+ // Calls to dtrace probes must generate unique patchpoints.
+ if (Name.starts_with("__dtrace"))
return false;
}
if (isCalleeOperand(CI, OpIdx) &&
@@ -105,7 +107,8 @@ bool isEligibleFunction(Function *F) {
if (F->isDeclaration())
return false;
- if (F->hasFnAttribute(llvm::Attribute::NoMerge))
+ if (F->hasFnAttribute(llvm::Attribute::NoMerge) ||
+ F->hasFnAttribute(llvm::Attribute::AlwaysInline))
return false;
if (F->hasAvailableExternallyLinkage())
@@ -552,8 +555,8 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
// Check if the matched functions fall into the same (first) module.
// This module check is not strictly necessary as the functions can move
// around. We just want to avoid merging functions from different
- // modules than the first one in the functon map, as they may not end up
- // with not being ICFed by the linker.
+ // modules than the first one in the function map, as they may not end
+ // up with being ICFed by the linker.
if (MergedModId != *FunctionMap->getNameForId(SF->ModuleNameId)) {
++NumMismatchedModuleId;
continue;
@@ -614,30 +617,6 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
return Changed;
}
-char GlobalMergeFunc::ID = 0;
-INITIALIZE_PASS_BEGIN(GlobalMergeFunc, "global-merge-func",
- "Global merge function pass", false, false)
-INITIALIZE_PASS_END(GlobalMergeFunc, "global-merge-func",
- "Global merge function pass", false, false)
-
-StringRef GlobalMergeFunc::getPassName() const {
- return "Global Merge Functions";
-}
-
-void GlobalMergeFunc::getAnalysisUsage(AnalysisUsage &AU) const {
- AU.addUsedIfAvailable<ImmutableModuleSummaryIndexWrapperPass>();
- AU.setPreservesAll();
- ModulePass::getAnalysisUsage(AU);
-}
-
-GlobalMergeFunc::GlobalMergeFunc() : ModulePass(ID) {
- initializeGlobalMergeFuncPass(*llvm::PassRegistry::getPassRegistry());
-}
-
-namespace llvm {
-Pass *createGlobalMergeFuncPass() { return new GlobalMergeFunc(); }
-} // namespace llvm
-
void GlobalMergeFunc::initializeMergerMode(const Module &M) {
// Initialize the local function map regardless of the merger mode.
LocalFunctionMap = std::make_unique<StableFunctionMap>();
@@ -646,14 +625,10 @@ void GlobalMergeFunc::initializeMergerMode(const Module &M) {
if (DisableGlobalMerging)
return;
- if (auto *IndexWrapperPass =
- getAnalysisIfAvailable<ImmutableModuleSummaryIndexWrapperPass>()) {
- auto *TheIndex = IndexWrapperPass->getIndex();
- // (Full)LTO module does not have functions added to the index.
- // In this case, we run a local merger without using codegen data.
- if (TheIndex && !TheIndex->hasExportedFunctions(M))
- return;
- }
+ // (Full)LTO module does not have functions added to the index.
+ // In this case, we run a local merger without using codegen data.
+ if (Index && !Index->hasExportedFunctions(M))
+ return;
if (cgdata::emitCGData())
MergerMode = HashFunctionMode::BuildingHashFuncion;
@@ -681,7 +656,7 @@ void GlobalMergeFunc::emitFunctionMap(Module &M) {
Align(4));
}
-bool GlobalMergeFunc::runOnModule(Module &M) {
+bool GlobalMergeFunc::run(Module &M) {
initializeMergerMode(M);
const StableFunctionMap *FuncMap;
@@ -700,3 +675,58 @@ bool GlobalMergeFunc::runOnModule(Module &M) {
return merge(M, FuncMap);
}
+
+namespace {
+
+class GlobalMergeFuncPassWrapper : public ModulePass {
+
+public:
+ static char ID;
+
+ GlobalMergeFuncPassWrapper();
+
+ void getAnalysisUsage(AnalysisUsage &AU) const override {
+ AU.addUsedIfAvailable<ImmutableModuleSummaryIndexWrapperPass>();
+ AU.setPreservesAll();
+ ModulePass::getAnalysisUsage(AU);
+ }
+
+ StringRef getPassName() const override { return "Global Merge Functions"; }
+
+ bool runOnModule(Module &M) override;
+};
+
+} // namespace
+
+char GlobalMergeFuncPassWrapper::ID = 0;
+INITIALIZE_PASS_BEGIN(GlobalMergeFuncPassWrapper, "global-merge-func",
+ "Global merge function pass", false, false)
+INITIALIZE_PASS_END(GlobalMergeFuncPassWrapper, "global-merge-func",
+ "Global merge function pass", false, false)
+
+namespace llvm {
+ModulePass *createGlobalMergeFuncPass() {
+ return new GlobalMergeFuncPassWrapper();
+}
+} // namespace llvm
+
+GlobalMergeFuncPassWrapper::GlobalMergeFuncPassWrapper() : ModulePass(ID) {
+ initializeGlobalMergeFuncPassWrapperPass(
+ *llvm::PassRegistry::getPassRegistry());
+}
+
+bool GlobalMergeFuncPassWrapper::runOnModule(Module &M) {
+ const ModuleSummaryIndex *Index = nullptr;
+ if (auto *IndexWrapperPass =
+ getAnalysisIfAvailable<ImmutableModuleSummaryIndexWrapperPass>())
+ Index = IndexWrapperPass->getIndex();
+
+ return GlobalMergeFunc(Index).run(M);
+}
+
+PreservedAnalyses GlobalMergeFuncPass::run(Module &M,
+ AnalysisManager<Module> &AM) {
+ ModuleSummaryIndex *Index = &(AM.getResult<ModuleSummaryIndexAnalysis>(M));
+ bool Changed = GlobalMergeFunc(Index).run(M);
+ return Changed ? PreservedAnalyses::none() : PreservedAnalyses::all();
+}
diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index beeb8ea2d078d9..f486351c1d6636 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -492,6 +492,7 @@ CGPassBuilderOption llvm::getCGPassBuilderOption() {
SET_BOOLEAN_OPTION(EarlyLiveIntervals)
SET_BOOLEAN_OPTION(EnableBlockPlacementStats)
+ SET_BOOLEAN_OPTION(EnableGlobalMergeFunc)
SET_BOOLEAN_OPTION(EnableImplicitNullChecks)
SET_BOOLEAN_OPTION(EnableMachineOutliner)
SET_BOOLEAN_OPTION(MISchedPostRA)
@@ -890,6 +891,9 @@ void TargetPassConfig::addIRPasses() {
// Convert conditional moves to conditional jumps when profitable.
if (getOptLevel() != CodeGenOptLevel::None && !DisableSelectOptimize)
addPass(createSelectOptimizePass());
+
+ if (EnableGlobalMergeFunc)
+ addPass(createGlobalMergeFuncPass());
}
/// Turn exception handling constructs into something the code generators can
diff --git a/llvm/lib/LTO/LTO.cpp b/llvm/lib/LTO/LTO.cpp
index 3f88c6c475d4d8..0f53c608512171 100644
--- a/llvm/lib/LTO/LTO.cpp
+++ b/llvm/lib/LTO/LTO.cpp
@@ -53,7 +53,6 @@
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Transforms/IPO.h"
-#include "llvm/Transforms/IPO/GlobalMergeFunctions.h"
#include "llvm/Transforms/IPO/MemProfContextDisambiguation.h"
#include "llvm/Transforms/IPO/WholeProgramDevirt.h"
#include "llvm/Transforms/Utils/FunctionImportUtils.h"
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index a879918005cad8..65eadd5aabbd89 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -90,6 +90,7 @@
#include "llvm/CodeGen/FinalizeISel.h"
#include "llvm/CodeGen/GCMetadata.h"
#include "llvm/CodeGen/GlobalMerge.h"
+#include "llvm/CodeGen/GlobalMergeFunctions.h"
#include "llvm/CodeGen/HardwareLoops.h"
#include "llvm/CodeGen/IndirectBrExpand.h"
#include "llvm/CodeGen/InterleavedAccess.h"
diff --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp
index 16fe9a74bb9c0d..997c23a6bb5a05 100644
--- a/llvm/lib/Passes/PassBuilderPipelines.cpp
+++ b/llvm/lib/Passes/PassBuilderPipelines.cpp
@@ -24,6 +24,7 @@
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/ScopedNoAliasAA.h"
#include "llvm/Analysis/TypeBasedAliasAnalysis.h"
+#include "llvm/CodeGen/GlobalMergeFunctions.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
#include "llvm/Passes/OptimizationLevel.h"
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 017ae311c55eb4..0de532eb232f93 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -69,6 +69,7 @@ MODULE_PASS("extract-blocks", BlockExtractorPass({}, false))
MODULE_PASS("expand-variadics", ExpandVariadicsPass(ExpandVariadicsMode::Disable))
MODULE_PASS("forceattrs", ForceFunctionAttrsPass())
MODULE_PASS("function-import", FunctionImportPass())
+MODULE_PASS("global-merge-func", GlobalMergeFuncPass())
MODULE_PASS("globalopt", GlobalOptPass())
MODULE_PASS("globalsplit", GlobalSplitPass())
MODULE_PASS("hipstdpar-interpose-alloc", HipStdParAllocationInterpositionPass())
diff --git a/llvm/lib/Transforms/IPO/CMakeLists.txt b/llvm/lib/Transforms/IPO/CMakeLists.txt
index 6a36ed64149f93..15cb57399d2460 100644
--- a/llvm/lib/Transforms/IPO/CMakeLists.txt
+++ b/llvm/lib/Transforms/IPO/CMakeLists.txt
@@ -21,7 +21,6 @@ add_llvm_component_library(LLVMipo
GlobalDCE.cpp
GlobalOpt.cpp
GlobalSplit.cpp
- GlobalMergeFunctions.cpp
HotColdSplitting.cpp
IPO.cpp
IROutliner.cpp
@@ -61,7 +60,6 @@ add_llvm_component_library(LLVMipo
Analysis
BitReader
BitWriter
- CGData
Core
FrontendOpenMP
InstCombine
diff --git a/llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll b/llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll
index 4f5f5c0b5b26d9..660ffe6109948f 100644
--- a/llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll
+++ b/llvm/test/ThinLTO/AArch64/cgdata-merge-local.ll
@@ -1,36 +1,51 @@
; This test checks if two similar functions, f1 and f2, can be merged locally within a single module
; while parameterizing a difference in their global variables, g1 and g2.
; To achieve this, we create two instances of the global merging function, f1.Tgm and f2.Tgm,
-; which are tail-called from thunks g1 and g2 respectively.
+; which are tail-called from thunks f1 and f2 respectively.
; These identical functions, f1.Tgm and f2.Tgm, will be folded by the linker via Identical Code Folding (IFC).
-; RUN: opt -module-summary -module-hash %s -o %t
+; RUN: opt -S --passes=global-merge-func %s | FileCheck %s
-; RUN: llvm-lto2 run -enable-global-merge-func=false %t -o %tout-nomerge \
-; RUN: -r %t,_f1,px \
-; RUN: -r %t,_f2,px \
-; RUN: -r %t,_g,l -r %t,_g1,l -r %t,_g2,l
-; RUN: llvm-nm %tout-nomerge.1 | FileCheck %s --check-prefix=NOMERGE
-; RUN: llvm-lto2 run -enable-global-merge-func=true %t -o %tout-merge \
-; RUN: -r %t,_f1,px \
-; RUN: -r %t,_f2,px \
-; RUN: -r %t,_g,l -r %t,_g1,l -r %t,_g2,l
-; RUN: llvm-nm %tout-merge.1 | FileCheck %s --check-prefix=GLOBALMERGE
-; RUN: llvm-objdump -d %tout-merge.1 | FileCheck %s --check-prefix=THUNK
+; A merging instance is created with additional parameter.
+; CHECK: define internal i32 @f1.Tgm(i32 %0, ptr %1)
+; CHECK-NEXT: entry:
+; CHECK-NEXT: %idxprom = sext i32 %0 to i64
+; CHECK-NEXT: %arrayidx = getelementptr inbounds [0 x i32], ptr @g, i64 0, i64 %idxprom
+; CHECK-NEXT: %2 = load i32, ptr %arrayidx, align 4
+; CHECK-NEXT: %3 = load volatile i32, ptr %1, align 4
+; CHECK-NEXT: %mul = mul nsw i32 %3, %2
+; CHECK-NEXT: %add = add nsw i32 %mul, 1
+; CHECK-NEXT: ret i32 %add
+
+; The original function becomes a thunk passing g1.
+; CHECK: define i32 @f1(i32 %a)
+; CHECK-NEXT: %1 = tail call i32 @f1.Tgm(i32 %a, ptr @g1)
+; CHECK-NEXT: ret i32 %1
+
+; A same sequence is produced for f2.Tgm.
+; CHECK: define internal i32 @f2.Tgm(i32 %0, ptr %1)
+; CHECK-NEXT: entry:
+; CHECK-NEXT: %idxprom = sext i32 %0 to i64
+; CHECK-NEXT: %arrayidx = getelementptr inbounds [0 x i32], ptr @g, i64 0, i64 %idxprom
+; CHECK-NEXT: %2 = load i32, ptr %arrayidx, align 4
+; CHECK-NEXT: %3 = load volatile i32, ptr %1, align 4
+; CHECK-NEXT: %mul = mul nsw i32 %3, %2
+; CHECK-NEXT: %add = add nsw i32 %mul, 1
+; CHECK-NEXT: ret i32 %add
+
+; The original function becomes a thunk passing g2.
+; CHECK: define i32 @f2(i32 %a)
+; CHECK-NEXT: %1 = tail call i32 @f2.Tgm(i32 %a, ptr @g2)
+; CHECK-NEXT: ret i32 %1
+
+; RUN: llc -enable-global-merge-func=true < %s | FileCheck %s --check-prefix=MERGE
+; RUN: llc -enable-global-merge-func=false < %s | FileCheck %s --check-prefix=NOMERGE
+
+; MERGE: _f1.Tgm
+; MERGE: _f2.Tgm
; NOMERGE-NOT: _f1.Tgm
-; GLOBALMERGE: _f1.Tgm
-; GLOBALMERGE: _f2.Tgm
-
-; THUNK: <_f1>:
-; THUNK-NEXT: adrp x1,
-; THUNK-NEXT: ldr x1, [x1]
-; THUNK-NEXT: b
-
-; THUNK: <_f2>:
-; THUNK-NEXT: adrp x1,
-; THUNK-NEXT: ldr x1, [x1]
-; THUNK-NEXT: b
+; NOMERGE-NOT: _f2.Tgm
target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
target triple = "arm64-unknown-ios12.0.0"
diff --git a/llvm/tools/llvm-lto2/CMakeLists.txt b/llvm/tools/llvm-lto2/CMakeLists.txt
index 6ddccc7f17442f..3b4644d6e27715 100644
--- a/llvm/tools/llvm-lto2/CMakeLists.txt
+++ b/llvm/tools/llvm-lto2/CMakeLists.txt
@@ -6,7 +6,6 @@ set(LLVM_LINK_COMPONENTS
BitReader
CodeGen
Core
- IPO
Linker
LTO
MC
diff --git a/llvm/tools/llvm-lto2/llvm-lto2.cpp b/llvm/tools/llvm-lto2/llvm-lto2.cpp
index 0dc6623552a4bd..d4f022ef021a44 100644
--- a/llvm/tools/llvm-lto2/llvm-lto2.cpp
+++ b/llvm/tools/llvm-lto2/llvm-lto2.cpp
@@ -28,7 +28,6 @@
#include "llvm/Support/PluginLoader.h"
#include "llvm/Support/TargetSelect.h"
#include "llvm/Support/Threading.h"
-#include "llvm/Transforms/IPO.h"
#include <atomic>
using namespace llvm;
@@ -196,7 +195,6 @@ static cl::opt<bool> TryUseNewDbgInfoFormat(
extern cl::opt<bool> UseNewDbgInfoFormat;
extern cl::opt<cl::boolOrDefault> LoadBitcodeIntoNewDbgInfoFormat;
extern cl::opt<cl::boolOrDefault> PreserveInputDbgFormat;
-extern cl::opt<bool> EnableGlobalMergeFunc;
static void check(Error E, std::string Msg) {
if (!E)
@@ -376,10 +374,6 @@ static int run(int argc, char **argv) {
if (DI.getSeverity() == DS_Error)
HasErrors = true;
};
- Conf.PreCodeGenPassesHook = [](legacy::PassManager &pm) {
- if (EnableGlobalMergeFunc)
- pm.add(createGlobalMergeFuncPass());
- };
LTO::LTOKind LTOMode = LTO::LTOK_Default;
>From 70070300bf1eefd9badc4767e0af9d36f73c5782 Mon Sep 17 00:00:00 2001
From: Kyungwoo Lee <kyulee at meta.com>
Date: Sun, 10 Nov 2024 08:55:00 -0800
Subject: [PATCH 5/7] Fix format
---
llvm/include/llvm/CodeGen/GlobalMergeFunctions.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/llvm/include/llvm/CodeGen/GlobalMergeFunctions.h b/llvm/include/llvm/CodeGen/GlobalMergeFunctions.h
index 982a66270f616e..82239e04dbd4fd 100644
--- a/llvm/include/llvm/CodeGen/GlobalMergeFunctions.h
+++ b/llvm/include/llvm/CodeGen/GlobalMergeFunctions.h
@@ -60,7 +60,7 @@ class GlobalMergeFunc {
/// becomes a thunk supplying contexts to the merged function via parameters.
static constexpr const char MergingInstanceSuffix[] = ".Tgm";
- GlobalMergeFunc(const ModuleSummaryIndex *Index) : Index(Index){};
+ GlobalMergeFunc(const ModuleSummaryIndex *Index) : Index(Index) {};
void initializeMergerMode(const Module &M);
>From 60f2f31ad46e78bf348b2548fca1f5419d0f18de Mon Sep 17 00:00:00 2001
From: Kyungwoo Lee <kyulee at meta.com>
Date: Sun, 10 Nov 2024 23:24:47 -0800
Subject: [PATCH 6/7] Change related to 2nd comments from nocchijiang
- Move isProfitable to offline (llvm-cgdata)
- skip-trim flag to skip trimming codegen data.
- The default behavior is to trim unnecessary content from the codegen
data.
- With this flag enabled, we skip trimming, which is often useful to
create a synthetic test.
---
llvm/include/llvm/CGData/StableFunctionMap.h | 2 +-
.../llvm/CGData/StableFunctionMapRecord.h | 2 +-
llvm/lib/CGData/StableFunctionMap.cpp | 71 ++++++++++++++++-
llvm/lib/CodeGen/GlobalMergeFunctions.cpp | 79 +++----------------
llvm/lib/CodeGen/TargetPassConfig.cpp | 2 +-
.../merge-combined-funcmap-hashtree.test | 2 +-
.../llvm-cgdata/merge-funcmap-archive.test | 2 +-
.../llvm-cgdata/merge-funcmap-concat.test | 2 +-
.../llvm-cgdata/merge-funcmap-double.test | 2 +-
.../llvm-cgdata/merge-funcmap-single.test | 2 +-
llvm/tools/llvm-cgdata/Opts.td | 1 +
llvm/tools/llvm-cgdata/llvm-cgdata.cpp | 4 +-
.../CGData/StableFunctionMapTest.cpp | 4 +-
13 files changed, 94 insertions(+), 81 deletions(-)
diff --git a/llvm/include/llvm/CGData/StableFunctionMap.h b/llvm/include/llvm/CGData/StableFunctionMap.h
index a2e1abb49a3eba..8881adf5889d0d 100644
--- a/llvm/include/llvm/CGData/StableFunctionMap.h
+++ b/llvm/include/llvm/CGData/StableFunctionMap.h
@@ -110,7 +110,7 @@ struct StableFunctionMap {
size_t size(SizeType Type = UniqueHashCount) const;
/// Finalize the stable function map by trimming content.
- void finalize();
+ void finalize(bool SkipTrim = false);
private:
/// Insert a `StableFunctionEntry` into the function map directly. This
diff --git a/llvm/include/llvm/CGData/StableFunctionMapRecord.h b/llvm/include/llvm/CGData/StableFunctionMapRecord.h
index 0517f2c20d72ff..f9b3ed7c646d6e 100644
--- a/llvm/include/llvm/CGData/StableFunctionMapRecord.h
+++ b/llvm/include/llvm/CGData/StableFunctionMapRecord.h
@@ -49,7 +49,7 @@ struct StableFunctionMapRecord {
void deserializeYAML(yaml::Input &YIS);
/// Finalize the stable function map by trimming content.
- void finalize() { FunctionMap->finalize(); }
+ void finalize(bool SkipTrim = false) { FunctionMap->finalize(SkipTrim); }
/// Merge the stable function map into this one.
void merge(const StableFunctionMapRecord &Other) {
diff --git a/llvm/lib/CGData/StableFunctionMap.cpp b/llvm/lib/CGData/StableFunctionMap.cpp
index cfef5b22fe7849..fe7be0c0b6e7b8 100644
--- a/llvm/lib/CGData/StableFunctionMap.cpp
+++ b/llvm/lib/CGData/StableFunctionMap.cpp
@@ -14,11 +14,43 @@
//===----------------------------------------------------------------------===//
#include "llvm/CGData/StableFunctionMap.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
#define DEBUG_TYPE "stable-function-map"
using namespace llvm;
+static cl::opt<unsigned>
+ GlobalMergingMinMerges("global-merging-min-merges",
+ cl::desc("Minimum number of similar functions with "
+ "the same hash required for merging."),
+ cl::init(2), cl::Hidden);
+static cl::opt<unsigned> GlobalMergingMinInstrs(
+ "global-merging-min-instrs",
+ cl::desc("The minimum instruction count required when merging functions."),
+ cl::init(1), cl::Hidden);
+static cl::opt<unsigned> GlobalMergingMaxParams(
+ "global-merging-max-params",
+ cl::desc(
+ "The maximum number of parameters allowed when merging functions."),
+ cl::init(std::numeric_limits<unsigned>::max()), cl::Hidden);
+static cl::opt<unsigned> GlobalMergingParamOverhead(
+ "global-merging-param-overhead",
+ cl::desc("The overhead cost associated with each parameter when merging "
+ "functions."),
+ cl::init(2), cl::Hidden);
+static cl::opt<unsigned>
+ GlobalMergingCallOverhead("global-merging-call-overhead",
+ cl::desc("The overhead cost associated with each "
+ "function call when merging functions."),
+ cl::init(1), cl::Hidden);
+static cl::opt<unsigned> GlobalMergingExtraThreshold(
+ "global-merging-extra-threshold",
+ cl::desc("An additional cost threshold that must be exceeded for merging "
+ "to be considered beneficial."),
+ cl::init(0), cl::Hidden);
+
unsigned StableFunctionMap::getIdOrCreateForName(StringRef Name) {
auto It = NameToId.find(Name);
if (It != NameToId.end())
@@ -117,7 +149,38 @@ static void removeIdenticalIndexPair(
SF->IndexOperandHashMap->erase(Pair);
}
-void StableFunctionMap::finalize() {
+static bool isProfitable(
+ const SmallVector<std::unique_ptr<StableFunctionMap::StableFunctionEntry>>
+ &SFS) {
+ unsigned StableFunctionCount = SFS.size();
+ if (StableFunctionCount < GlobalMergingMinMerges)
+ return false;
+
+ unsigned InstCount = SFS[0]->InstCount;
+ if (InstCount < GlobalMergingMinInstrs)
+ return false;
+
+ unsigned ParamCount = SFS[0]->IndexOperandHashMap->size();
+ if (ParamCount > GlobalMergingMaxParams)
+ return false;
+
+ unsigned Benefit = InstCount * (StableFunctionCount - 1);
+ unsigned Cost =
+ (GlobalMergingParamOverhead * ParamCount + GlobalMergingCallOverhead) *
+ StableFunctionCount +
+ GlobalMergingExtraThreshold;
+
+ bool Result = Benefit > Cost;
+ LLVM_DEBUG(dbgs() << "isProfitable: Hash = " << SFS[0]->Hash << ", "
+ << "StableFunctionCount = " << StableFunctionCount
+ << ", InstCount = " << InstCount
+ << ", ParamCount = " << ParamCount
+ << ", Benefit = " << Benefit << ", Cost = " << Cost
+ << ", Result = " << (Result ? "true" : "false") << "\n");
+ return Result;
+}
+
+void StableFunctionMap::finalize(bool SkipTrim) {
for (auto It = HashToFuncs.begin(); It != HashToFuncs.end(); ++It) {
auto &[StableHash, SFS] = *It;
@@ -158,9 +221,15 @@ void StableFunctionMap::finalize() {
continue;
}
+ if (SkipTrim)
+ continue;
+
// Trim the index pair that has the same operand hash across
// stable functions.
removeIdenticalIndexPair(SFS);
+
+ if (!isProfitable(SFS))
+ HashToFuncs.erase(It);
}
Finalized = true;
diff --git a/llvm/lib/CodeGen/GlobalMergeFunctions.cpp b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
index 46b4ea76b655ff..4ec9b8b2e6af8e 100644
--- a/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
+++ b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
@@ -31,30 +31,6 @@ static cl::opt<bool>
"the codegen data generation or use. Local "
"merging is still enabled within a module."),
cl::init(false));
-static cl::opt<unsigned> GlobalMergingMinInstrs(
- "global-merging-min-instrs",
- cl::desc("The minimum instruction count required when merging functions."),
- cl::init(1), cl::Hidden);
-static cl::opt<unsigned> GlobalMergingMaxParams(
- "global-merging-max-params",
- cl::desc(
- "The maximum number of parameters allowed when merging functions."),
- cl::init(std::numeric_limits<unsigned>::max()), cl::Hidden);
-static cl::opt<unsigned> GlobalMergingParamOverhead(
- "global-merging-param-overhead",
- cl::desc("The overhead cost associated with each parameter when merging "
- "functions."),
- cl::init(2), cl::Hidden);
-static cl::opt<unsigned>
- GlobalMergingCallOverhead("global-merging-call-overhead",
- cl::desc("The overhead cost associated with each "
- "function call when merging functions."),
- cl::init(1), cl::Hidden);
-static cl::opt<unsigned> GlobalMergingExtraThreshold(
- "global-merging-extra-threshold",
- cl::desc("An additional cost threshold that must be exceeded for merging "
- "to be considered beneficial."),
- cl::init(0), cl::Hidden);
STATISTIC(NumMismatchedFunctionHash,
"Number of mismatched function hash for global merge function");
@@ -442,40 +418,6 @@ static ParamLocsVecTy computeParamInfo(
return ParamLocsVec;
}
-static bool isProfitable(
- const SmallVector<std::unique_ptr<StableFunctionMap::StableFunctionEntry>>
- &SFS,
- const Function *F) {
- // No interest if the number of candidates are less than 2.
- unsigned StableFunctionCount = SFS.size();
- if (StableFunctionCount < 2)
- return false;
-
- unsigned InstCount = SFS[0]->InstCount;
- if (InstCount < GlobalMergingMinInstrs)
- return false;
-
- unsigned ParamCount = SFS[0]->IndexOperandHashMap->size();
- unsigned TotalParamCount = ParamCount + F->getFunctionType()->getNumParams();
- if (TotalParamCount > GlobalMergingMaxParams)
- return false;
-
- unsigned Benefit = InstCount * (StableFunctionCount - 1);
- unsigned Cost =
- (GlobalMergingParamOverhead * ParamCount + GlobalMergingCallOverhead) *
- StableFunctionCount +
- GlobalMergingExtraThreshold;
-
- bool Result = Benefit > Cost;
- LLVM_DEBUG(dbgs() << "isProfitable: Function = " << F->getName() << ", "
- << "StableFunctionCount = " << StableFunctionCount
- << ", InstCount = " << InstCount
- << ", ParamCount = " << ParamCount
- << ", Benefit = " << Benefit << ", Cost = " << Cost
- << ", Result = " << (Result ? "true" : "false") << "\n");
- return Result;
-}
-
bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
bool Changed = false;
@@ -488,12 +430,9 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
auto ModId = M.getModuleIdentifier();
for (auto &[Hash, SFS] : FunctionMap->getFunctionMap()) {
- // Compute the parameter locations based on the unique hash sequences
+ // Parameter locations based on the unique hash sequences
// across the candidates.
- auto ParamLocsVec = computeParamInfo(SFS);
- LLVM_DEBUG(dbgs() << "[GlobalMergeFunc] Merging hash: " << Hash
- << " with Params " << ParamLocsVec.size() << "\n");
-
+ std::optional<ParamLocsVecTy> ParamLocsVec;
Function *MergedFunc = nullptr;
std::string MergedModId;
SmallVector<FuncMergeInfo> FuncMergeInfos;
@@ -542,15 +481,17 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
++NumMismatchedConstHash;
continue;
}
+ if (!ParamLocsVec.has_value()) {
+ ParamLocsVec = computeParamInfo(SFS);
+ LLVM_DEBUG(dbgs() << "[GlobalMergeFunc] Merging hash: " << Hash
+ << " with Params " << ParamLocsVec.size() << "\n");
+ }
if (!checkConstLocationCompatible(*SF, *FI.IndexInstruction,
- ParamLocsVec)) {
+ *ParamLocsVec)) {
++NumMismatchedConstHash;
continue;
}
- if (!isProfitable(SFS, F))
- break;
-
if (MergedFunc) {
// Check if the matched functions fall into the same (first) module.
// This module check is not strictly necessary as the functions can move
@@ -583,7 +524,7 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
// the parameters. Populate parameters pointing to the original constants.
SmallVector<Constant *> Params;
SmallVector<Type *> ParamTypes;
- for (auto &ParamLocs : ParamLocsVec) {
+ for (auto &ParamLocs : *ParamLocsVec) {
assert(!ParamLocs.empty());
auto &[InstIndex, OpndIndex] = ParamLocs[0];
auto *Inst = FMI.IndexInstruction->lookup(InstIndex);
@@ -594,7 +535,7 @@ bool GlobalMergeFunc::merge(Module &M, const StableFunctionMap *FunctionMap) {
// Create a merged function derived from the current function.
Function *MergedFunc =
- createMergedFunction(FMI, ParamTypes, ParamLocsVec);
+ createMergedFunction(FMI, ParamTypes, *ParamLocsVec);
LLVM_DEBUG({
dbgs() << "[GlobalMergeFunc] Merged function (hash:" << FMI.SF->Hash
diff --git a/llvm/lib/CodeGen/TargetPassConfig.cpp b/llvm/lib/CodeGen/TargetPassConfig.cpp
index f486351c1d6636..b1fd1f5f224953 100644
--- a/llvm/lib/CodeGen/TargetPassConfig.cpp
+++ b/llvm/lib/CodeGen/TargetPassConfig.cpp
@@ -141,7 +141,7 @@ static cl::opt<RunOutliner> EnableMachineOutliner(
"Disable all outlining"),
// Sentinel value for unspecified option.
clEnumValN(RunOutliner::AlwaysOutline, "", "")));
-cl::opt<bool> EnableGlobalMergeFunc(
+static cl::opt<bool> EnableGlobalMergeFunc(
"enable-global-merge-func", cl::Hidden,
cl::desc("Enable global merge functions that are based on hash function"));
// Disable the pass to fix unwind information. Whether the pass is included in
diff --git a/llvm/test/tools/llvm-cgdata/merge-combined-funcmap-hashtree.test b/llvm/test/tools/llvm-cgdata/merge-combined-funcmap-hashtree.test
index b9bf067d3771c5..f7e078ba8efa3c 100644
--- a/llvm/test/tools/llvm-cgdata/merge-combined-funcmap-hashtree.test
+++ b/llvm/test/tools/llvm-cgdata/merge-combined-funcmap-hashtree.test
@@ -21,7 +21,7 @@ RUN: sed "s/<RAW_2_BYTES>/$(cat %t/raw-funcmap-bytes.txt)/g" %t/merge-both-hasht
RUN: llc -filetype=obj -mtriple arm64-apple-darwin %t/merge-both-hashtree-funcmap.ll -o %t/merge-both-hashtree-funcmap.o
# Merge an object file having cgdata (__llvm_outline and __llvm_merge)
-RUN: llvm-cgdata -m %t/merge-both-hashtree-funcmap.o -o %t/merge-both-hashtree-funcmap.cgdata
+RUN: llvm-cgdata -m --skip-trim %t/merge-both-hashtree-funcmap.o -o %t/merge-both-hashtree-funcmap.cgdata
RUN: llvm-cgdata -s %t/merge-both-hashtree-funcmap.cgdata | FileCheck %s
CHECK: Outlined hash tree:
diff --git a/llvm/test/tools/llvm-cgdata/merge-funcmap-archive.test b/llvm/test/tools/llvm-cgdata/merge-funcmap-archive.test
index f643c8d92073e3..c1881bc870aadc 100644
--- a/llvm/test/tools/llvm-cgdata/merge-funcmap-archive.test
+++ b/llvm/test/tools/llvm-cgdata/merge-funcmap-archive.test
@@ -21,7 +21,7 @@ RUN: llc -filetype=obj -mtriple arm64-apple-darwin %t/merge-2.ll -o %t/merge-2.o
RUN: llvm-ar rcs %t/merge-archive.a %t/merge-1.o %t/merge-2.o
# Merge the archive into the codegen data file.
-RUN: llvm-cgdata --merge %t/merge-archive.a -o %t/merge-archive.cgdata
+RUN: llvm-cgdata --merge --skip-trim %t/merge-archive.a -o %t/merge-archive.cgdata
RUN: llvm-cgdata --show %t/merge-archive.cgdata | FileCheck %s
RUN: llvm-cgdata --show %t/merge-archive.cgdata| FileCheck %s
diff --git a/llvm/test/tools/llvm-cgdata/merge-funcmap-concat.test b/llvm/test/tools/llvm-cgdata/merge-funcmap-concat.test
index c8acf1f3916e5a..301ee6dcf21c8c 100644
--- a/llvm/test/tools/llvm-cgdata/merge-funcmap-concat.test
+++ b/llvm/test/tools/llvm-cgdata/merge-funcmap-concat.test
@@ -15,7 +15,7 @@ RUN: od -t x1 -j 32 -An %t/raw-2.cgdata | tr -d '\n\r\t' | sed 's/[ ]*$//' | sed
RUN: sed "s/<RAW_2_BYTES>/$(cat %t/raw-2-bytes.txt)/g" %t/merge-concat-template-2.ll > %t/merge-concat.ll
RUN: llc -filetype=obj -mtriple arm64-apple-darwin %t/merge-concat.ll -o %t/merge-concat.o
-RUN: llvm-cgdata --merge %t/merge-concat.o -o %t/merge-concat.cgdata
+RUN: llvm-cgdata --merge --skip-trim %t/merge-concat.o -o %t/merge-concat.cgdata
RUN: llvm-cgdata --show %t/merge-concat.cgdata | FileCheck %s
CHECK: Stable function map:
diff --git a/llvm/test/tools/llvm-cgdata/merge-funcmap-double.test b/llvm/test/tools/llvm-cgdata/merge-funcmap-double.test
index 3ae67f062f820f..98a91487aa8401 100644
--- a/llvm/test/tools/llvm-cgdata/merge-funcmap-double.test
+++ b/llvm/test/tools/llvm-cgdata/merge-funcmap-double.test
@@ -18,7 +18,7 @@ RUN: sed "s/<RAW_2_BYTES>/$(cat %t/raw-2-bytes.txt)/g" %t/merge-2-template.ll >
RUN: llc -filetype=obj -mtriple arm64-apple-darwin %t/merge-2.ll -o %t/merge-2.o
# Merge two object files into the codegen data file.
-RUN: llvm-cgdata --merge %t/merge-1.o %t/merge-2.o -o %t/merge.cgdata
+RUN: llvm-cgdata --merge --skip-trim %t/merge-1.o %t/merge-2.o -o %t/merge.cgdata
RUN: llvm-cgdata --show %t/merge.cgdata | FileCheck %s
CHECK: Stable function map:
diff --git a/llvm/test/tools/llvm-cgdata/merge-funcmap-single.test b/llvm/test/tools/llvm-cgdata/merge-funcmap-single.test
index 6a4e635f638657..2075face72ab93 100644
--- a/llvm/test/tools/llvm-cgdata/merge-funcmap-single.test
+++ b/llvm/test/tools/llvm-cgdata/merge-funcmap-single.test
@@ -13,7 +13,7 @@ RUN: sed "s/<RAW_1_BYTES>/$(cat %t/raw-single-bytes.txt)/g" %t/merge-single-temp
RUN: llc -filetype=obj -mtriple arm64-apple-darwin %t/merge-single.ll -o %t/merge-single.o
# Merge an object file having cgdata (__llvm_merge)
-RUN: llvm-cgdata -m %t/merge-single.o -o %t/merge-single.cgdata
+RUN: llvm-cgdata -m --skip-trim %t/merge-single.o -o %t/merge-single.cgdata
RUN: llvm-cgdata -s %t/merge-single.cgdata | FileCheck %s
CHECK: Stable function map:
CHECK-NEXT: Unique hash Count: 1
diff --git a/llvm/tools/llvm-cgdata/Opts.td b/llvm/tools/llvm-cgdata/Opts.td
index b2cfc6a85bbd32..8da933f744e87a 100644
--- a/llvm/tools/llvm-cgdata/Opts.td
+++ b/llvm/tools/llvm-cgdata/Opts.td
@@ -24,6 +24,7 @@ def : F<"m", "Alias for --merge">, Alias<merge>, Group<action_group>;
// Additional options
def cgdata_version : FF<"cgdata-version", "Display the cgdata version">;
+def skip_trim : FF<"skip-trim", "Skip trimming content when merging the cgdata">;
def output : Option<["--"], "output", KIND_SEPARATE>,
HelpText<"Specify the name for the output file to be created">, MetaVarName<"<file>">;
def : JoinedOrSeparate<["-"], "o">, Alias<output>, MetaVarName<"<file>">, HelpText<"Alias for --output">;
diff --git a/llvm/tools/llvm-cgdata/llvm-cgdata.cpp b/llvm/tools/llvm-cgdata/llvm-cgdata.cpp
index 0931cad4bcb7ed..d33459b194c9a3 100644
--- a/llvm/tools/llvm-cgdata/llvm-cgdata.cpp
+++ b/llvm/tools/llvm-cgdata/llvm-cgdata.cpp
@@ -76,6 +76,7 @@ static StringRef ToolName;
static StringRef OutputFilename = "-";
static StringRef Filename;
static bool ShowCGDataVersion;
+static bool SkipTrim;
static CGDataAction Action;
static std::optional<CGDataFormat> OutputFormat;
static std::vector<std::string> InputFilenames;
@@ -214,7 +215,7 @@ static int merge_main(int argc, const char *argv[]) {
if (!Result)
exitWithError("failed to merge codegen data files.");
- GlobalFunctionMapRecord.finalize();
+ GlobalFunctionMapRecord.finalize(SkipTrim);
CodeGenDataWriter Writer;
if (!GlobalOutlineRecord.empty())
@@ -301,6 +302,7 @@ static void parseArgs(int argc, char **argv) {
}
ShowCGDataVersion = Args.hasArg(OPT_cgdata_version);
+ SkipTrim = Args.hasArg(OPT_skip_trim);
if (opt::Arg *A = Args.getLastArg(OPT_format)) {
StringRef OF = A->getValue();
diff --git a/llvm/unittests/CGData/StableFunctionMapTest.cpp b/llvm/unittests/CGData/StableFunctionMapTest.cpp
index 5e178dcd667240..d551ac8a814f4f 100644
--- a/llvm/unittests/CGData/StableFunctionMapTest.cpp
+++ b/llvm/unittests/CGData/StableFunctionMapTest.cpp
@@ -108,8 +108,8 @@ TEST(StableFunctionMap, Finalize2) {
TEST(StableFunctionMap, Finalize3) {
StableFunctionMap Map;
- StableFunction Func1{1, "Func1", "Mod1", 2, {{{0, 1}, 3}, {{1, 1}, 1}}};
- StableFunction Func2{1, "Func2", "Mod2", 2, {{{0, 1}, 2}, {{1, 1}, 1}}};
+ StableFunction Func1{1, "Func1", "Mod1", 12, {{{0, 1}, 3}, {{1, 1}, 1}}};
+ StableFunction Func2{1, "Func2", "Mod2", 12, {{{0, 1}, 2}, {{1, 1}, 1}}};
Map.insert(Func1);
Map.insert(Func2);
>From 23d6eb2a8bde23b8243a07ab08deac8407decb9f Mon Sep 17 00:00:00 2001
From: Kyungwoo Lee <kyulee at meta.com>
Date: Mon, 11 Nov 2024 00:48:45 -0800
Subject: [PATCH 7/7] Address comments from thevinster
---
llvm/lib/CodeGen/GlobalMergeFunctions.cpp | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/llvm/lib/CodeGen/GlobalMergeFunctions.cpp b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
index 4ec9b8b2e6af8e..652de8ea4f69c6 100644
--- a/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
+++ b/llvm/lib/CodeGen/GlobalMergeFunctions.cpp
@@ -25,12 +25,11 @@
using namespace llvm;
using namespace llvm::support;
-static cl::opt<bool>
- DisableGlobalMerging("disable-global-merging", cl::Hidden,
- cl::desc("Disable global merging only by ignoring "
- "the codegen data generation or use. Local "
- "merging is still enabled within a module."),
- cl::init(false));
+static cl::opt<bool> DisableCGDataForMerging(
+ "disable-cgdata-for-merging", cl::Hidden,
+ cl::desc("Disable codegen data for function merging. Local "
+ "merging is still enabled within a module."),
+ cl::init(false));
STATISTIC(NumMismatchedFunctionHash,
"Number of mismatched function hash for global merge function");
@@ -562,8 +561,8 @@ void GlobalMergeFunc::initializeMergerMode(const Module &M) {
// Initialize the local function map regardless of the merger mode.
LocalFunctionMap = std::make_unique<StableFunctionMap>();
- // Skip the global merge mode. The local merge is still enabled.
- if (DisableGlobalMerging)
+ // Disable codegen data for merging. The local merge is still enabled.
+ if (DisableCGDataForMerging)
return;
// (Full)LTO module does not have functions added to the index.
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