mirror of
https://github.com/c64scene-ar/llvm-6502.git
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110022 91177308-0d34-0410-b5e6-96231b3b80d8
796 lines
26 KiB
C++
796 lines
26 KiB
C++
//===- MergeFunctions.cpp - Merge identical functions ---------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This pass looks for equivalent functions that are mergable and folds them.
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//
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// A hash is computed from the function, based on its type and number of
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// basic blocks.
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//
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// Once all hashes are computed, we perform an expensive equality comparison
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// on each function pair. This takes n^2/2 comparisons per bucket, so it's
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// important that the hash function be high quality. The equality comparison
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// iterates through each instruction in each basic block.
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//
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// When a match is found the functions are folded. If both functions are
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// overridable, we move the functionality into a new internal function and
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// leave two overridable thunks to it.
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//
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//===----------------------------------------------------------------------===//
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//
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// Future work:
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//
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// * virtual functions.
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//
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// Many functions have their address taken by the virtual function table for
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// the object they belong to. However, as long as it's only used for a lookup
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// and call, this is irrelevant, and we'd like to fold such implementations.
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//
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// * switch from n^2 pair-wise comparisons to an n-way comparison for each
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// bucket.
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//
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// * be smarter about bitcast.
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//
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// In order to fold functions, we will sometimes add either bitcast instructions
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// or bitcast constant expressions. Unfortunately, this can confound further
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// analysis since the two functions differ where one has a bitcast and the
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// other doesn't. We should learn to peer through bitcasts without imposing bad
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// performance properties.
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//
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// * emit aliases for ELF
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//
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// ELF supports symbol aliases which are represented with GlobalAlias in the
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// Module, and we could emit them in the case that the addresses don't need to
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// be distinct. The problem is that not all object formats support equivalent
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// functionality. There's a few approaches to this problem;
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// a) teach codegen to lower global aliases to thunks on platforms which don't
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// support them.
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// b) always emit thunks, and create a separate thunk-to-alias pass which
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// runs on ELF systems. This has the added benefit of transforming other
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// thunks such as those produced by a C++ frontend into aliases when legal
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// to do so.
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//
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//===----------------------------------------------------------------------===//
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#define DEBUG_TYPE "mergefunc"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/FoldingSet.h"
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#include "llvm/ADT/SmallSet.h"
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#include "llvm/ADT/Statistic.h"
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#include "llvm/Constants.h"
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#include "llvm/InlineAsm.h"
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#include "llvm/Instructions.h"
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#include "llvm/LLVMContext.h"
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#include "llvm/Module.h"
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#include "llvm/Pass.h"
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#include "llvm/Support/CallSite.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/raw_ostream.h"
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#include "llvm/Target/TargetData.h"
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#include <map>
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#include <vector>
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using namespace llvm;
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STATISTIC(NumFunctionsMerged, "Number of functions merged");
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namespace {
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/// MergeFunctions finds functions which will generate identical machine code,
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/// by considering all pointer types to be equivalent. Once identified,
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/// MergeFunctions will fold them by replacing a call to one to a call to a
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/// bitcast of the other.
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///
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struct MergeFunctions : public ModulePass {
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static char ID; // Pass identification, replacement for typeid
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MergeFunctions() : ModulePass(&ID) {}
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bool runOnModule(Module &M);
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};
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}
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char MergeFunctions::ID = 0;
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INITIALIZE_PASS(MergeFunctions, "mergefunc", "Merge Functions", false, false);
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ModulePass *llvm::createMergeFunctionsPass() {
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return new MergeFunctions();
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}
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// ===----------------------------------------------------------------------===
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// Comparison of functions
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// ===----------------------------------------------------------------------===
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namespace {
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class FunctionComparator {
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public:
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FunctionComparator(TargetData *TD, Function *F1, Function *F2)
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: F1(F1), F2(F2), TD(TD) {}
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// Compare - test whether the two functions have equivalent behaviour.
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bool Compare();
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private:
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// Compare - test whether two basic blocks have equivalent behaviour.
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bool Compare(const BasicBlock *BB1, const BasicBlock *BB2);
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// getDomain - a value's domain is its parent function if it is specific to a
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// function, or NULL otherwise.
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const Function *getDomain(const Value *V) const;
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// Enumerate - Assign or look up previously assigned numbers for the two
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// values, and return whether the numbers are equal. Numbers are assigned in
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// the order visited.
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bool Enumerate(const Value *V1, const Value *V2);
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// isEquivalentOperation - Compare two Instructions for equivalence, similar
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// to Instruction::isSameOperationAs but with modifications to the type
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// comparison.
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bool isEquivalentOperation(const Instruction *I1,
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const Instruction *I2) const;
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// isEquivalentGEP - Compare two GEPs for equivalent pointer arithmetic.
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bool isEquivalentGEP(const GEPOperator *GEP1, const GEPOperator *GEP2);
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bool isEquivalentGEP(const GetElementPtrInst *GEP1,
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const GetElementPtrInst *GEP2) {
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return isEquivalentGEP(cast<GEPOperator>(GEP1), cast<GEPOperator>(GEP2));
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}
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// isEquivalentType - Compare two Types, treating all pointer types as equal.
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bool isEquivalentType(const Type *Ty1, const Type *Ty2) const;
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// The two functions undergoing comparison.
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Function *F1, *F2;
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TargetData *TD;
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typedef DenseMap<const Value *, unsigned long> IDMap;
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IDMap Map;
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DenseMap<const Function *, IDMap> Domains;
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DenseMap<const Function *, unsigned long> DomainCount;
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};
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}
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/// Compute a number which is guaranteed to be equal for two equivalent
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/// functions, but is very likely to be different for different functions. This
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/// needs to be computed as efficiently as possible.
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static unsigned long ProfileFunction(const Function *F) {
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const FunctionType *FTy = F->getFunctionType();
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FoldingSetNodeID ID;
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ID.AddInteger(F->size());
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ID.AddInteger(F->getCallingConv());
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ID.AddBoolean(F->hasGC());
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ID.AddBoolean(FTy->isVarArg());
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ID.AddInteger(FTy->getReturnType()->getTypeID());
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for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
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ID.AddInteger(FTy->getParamType(i)->getTypeID());
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return ID.ComputeHash();
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}
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/// isEquivalentType - any two pointers are equivalent. Otherwise, standard
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/// type equivalence rules apply.
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bool FunctionComparator::isEquivalentType(const Type *Ty1,
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const Type *Ty2) const {
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if (Ty1 == Ty2)
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return true;
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if (Ty1->getTypeID() != Ty2->getTypeID())
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return false;
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switch(Ty1->getTypeID()) {
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default:
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llvm_unreachable("Unknown type!");
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// Fall through in Release mode.
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case Type::IntegerTyID:
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case Type::OpaqueTyID:
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// Ty1 == Ty2 would have returned true earlier.
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return false;
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case Type::VoidTyID:
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case Type::FloatTyID:
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case Type::DoubleTyID:
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case Type::X86_FP80TyID:
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case Type::FP128TyID:
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case Type::PPC_FP128TyID:
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case Type::LabelTyID:
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case Type::MetadataTyID:
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return true;
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case Type::PointerTyID: {
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const PointerType *PTy1 = cast<PointerType>(Ty1);
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const PointerType *PTy2 = cast<PointerType>(Ty2);
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return PTy1->getAddressSpace() == PTy2->getAddressSpace();
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}
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case Type::StructTyID: {
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const StructType *STy1 = cast<StructType>(Ty1);
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const StructType *STy2 = cast<StructType>(Ty2);
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if (STy1->getNumElements() != STy2->getNumElements())
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return false;
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if (STy1->isPacked() != STy2->isPacked())
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return false;
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for (unsigned i = 0, e = STy1->getNumElements(); i != e; ++i) {
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if (!isEquivalentType(STy1->getElementType(i), STy2->getElementType(i)))
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return false;
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}
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return true;
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}
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case Type::UnionTyID: {
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const UnionType *UTy1 = cast<UnionType>(Ty1);
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const UnionType *UTy2 = cast<UnionType>(Ty2);
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// TODO: we could be fancy with union(A, union(A, B)) === union(A, B), etc.
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if (UTy1->getNumElements() != UTy2->getNumElements())
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return false;
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for (unsigned i = 0, e = UTy1->getNumElements(); i != e; ++i) {
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if (!isEquivalentType(UTy1->getElementType(i), UTy2->getElementType(i)))
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return false;
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}
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return true;
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}
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case Type::FunctionTyID: {
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const FunctionType *FTy1 = cast<FunctionType>(Ty1);
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const FunctionType *FTy2 = cast<FunctionType>(Ty2);
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if (FTy1->getNumParams() != FTy2->getNumParams() ||
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FTy1->isVarArg() != FTy2->isVarArg())
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return false;
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if (!isEquivalentType(FTy1->getReturnType(), FTy2->getReturnType()))
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return false;
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for (unsigned i = 0, e = FTy1->getNumParams(); i != e; ++i) {
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if (!isEquivalentType(FTy1->getParamType(i), FTy2->getParamType(i)))
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return false;
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}
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return true;
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}
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case Type::ArrayTyID: {
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const ArrayType *ATy1 = cast<ArrayType>(Ty1);
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const ArrayType *ATy2 = cast<ArrayType>(Ty2);
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return ATy1->getNumElements() == ATy2->getNumElements() &&
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isEquivalentType(ATy1->getElementType(), ATy2->getElementType());
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}
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case Type::VectorTyID: {
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const VectorType *VTy1 = cast<VectorType>(Ty1);
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const VectorType *VTy2 = cast<VectorType>(Ty2);
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return VTy1->getNumElements() == VTy2->getNumElements() &&
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isEquivalentType(VTy1->getElementType(), VTy2->getElementType());
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}
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}
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}
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/// isEquivalentOperation - determine whether the two operations are the same
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/// except that pointer-to-A and pointer-to-B are equivalent. This should be
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/// kept in sync with Instruction::isSameOperationAs.
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bool FunctionComparator::isEquivalentOperation(const Instruction *I1,
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const Instruction *I2) const {
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if (I1->getOpcode() != I2->getOpcode() ||
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I1->getNumOperands() != I2->getNumOperands() ||
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!isEquivalentType(I1->getType(), I2->getType()) ||
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!I1->hasSameSubclassOptionalData(I2))
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return false;
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// We have two instructions of identical opcode and #operands. Check to see
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// if all operands are the same type
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for (unsigned i = 0, e = I1->getNumOperands(); i != e; ++i)
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if (!isEquivalentType(I1->getOperand(i)->getType(),
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I2->getOperand(i)->getType()))
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return false;
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// Check special state that is a part of some instructions.
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if (const LoadInst *LI = dyn_cast<LoadInst>(I1))
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return LI->isVolatile() == cast<LoadInst>(I2)->isVolatile() &&
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LI->getAlignment() == cast<LoadInst>(I2)->getAlignment();
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if (const StoreInst *SI = dyn_cast<StoreInst>(I1))
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return SI->isVolatile() == cast<StoreInst>(I2)->isVolatile() &&
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SI->getAlignment() == cast<StoreInst>(I2)->getAlignment();
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if (const CmpInst *CI = dyn_cast<CmpInst>(I1))
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return CI->getPredicate() == cast<CmpInst>(I2)->getPredicate();
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if (const CallInst *CI = dyn_cast<CallInst>(I1))
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return CI->isTailCall() == cast<CallInst>(I2)->isTailCall() &&
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CI->getCallingConv() == cast<CallInst>(I2)->getCallingConv() &&
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CI->getAttributes().getRawPointer() ==
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cast<CallInst>(I2)->getAttributes().getRawPointer();
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if (const InvokeInst *CI = dyn_cast<InvokeInst>(I1))
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return CI->getCallingConv() == cast<InvokeInst>(I2)->getCallingConv() &&
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CI->getAttributes().getRawPointer() ==
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cast<InvokeInst>(I2)->getAttributes().getRawPointer();
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if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(I1)) {
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if (IVI->getNumIndices() != cast<InsertValueInst>(I2)->getNumIndices())
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return false;
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for (unsigned i = 0, e = IVI->getNumIndices(); i != e; ++i)
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if (IVI->idx_begin()[i] != cast<InsertValueInst>(I2)->idx_begin()[i])
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return false;
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return true;
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}
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if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I1)) {
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if (EVI->getNumIndices() != cast<ExtractValueInst>(I2)->getNumIndices())
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return false;
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for (unsigned i = 0, e = EVI->getNumIndices(); i != e; ++i)
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if (EVI->idx_begin()[i] != cast<ExtractValueInst>(I2)->idx_begin()[i])
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return false;
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return true;
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}
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return true;
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}
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/// isEquivalentGEP - determine whether two GEP operations perform the same
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/// underlying arithmetic.
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bool FunctionComparator::isEquivalentGEP(const GEPOperator *GEP1,
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const GEPOperator *GEP2) {
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// When we have target data, we can reduce the GEP down to the value in bytes
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// added to the address.
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if (TD && GEP1->hasAllConstantIndices() && GEP2->hasAllConstantIndices()) {
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SmallVector<Value *, 8> Indices1(GEP1->idx_begin(), GEP1->idx_end());
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SmallVector<Value *, 8> Indices2(GEP2->idx_begin(), GEP2->idx_end());
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uint64_t Offset1 = TD->getIndexedOffset(GEP1->getPointerOperandType(),
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Indices1.data(), Indices1.size());
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uint64_t Offset2 = TD->getIndexedOffset(GEP2->getPointerOperandType(),
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Indices2.data(), Indices2.size());
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return Offset1 == Offset2;
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}
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if (GEP1->getPointerOperand()->getType() !=
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GEP2->getPointerOperand()->getType())
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return false;
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if (GEP1->getNumOperands() != GEP2->getNumOperands())
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return false;
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for (unsigned i = 0, e = GEP1->getNumOperands(); i != e; ++i) {
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if (!Enumerate(GEP1->getOperand(i), GEP2->getOperand(i)))
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return false;
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}
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return true;
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}
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/// getDomain - a value's domain is its parent function if it is specific to a
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/// function, or NULL otherwise.
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const Function *FunctionComparator::getDomain(const Value *V) const {
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if (const Argument *A = dyn_cast<Argument>(V)) {
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return A->getParent();
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} else if (const BasicBlock *BB = dyn_cast<BasicBlock>(V)) {
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return BB->getParent();
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} else if (const Instruction *I = dyn_cast<Instruction>(V)) {
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return I->getParent()->getParent();
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}
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return NULL;
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}
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/// Enumerate - Compare two values used by the two functions under pair-wise
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/// comparison. If this is the first time the values are seen, they're added to
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/// the mapping so that we will detect mismatches on next use.
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bool FunctionComparator::Enumerate(const Value *V1, const Value *V2) {
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// Check for function @f1 referring to itself and function @f2 referring to
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// itself, or referring to each other, or both referring to either of them.
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// They're all equivalent if the two functions are otherwise equivalent.
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if (V1 == F1 || V1 == F2)
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if (V2 == F1 || V2 == F2)
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return true;
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// TODO: constant expressions with GEP or references to F1 or F2.
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if (isa<Constant>(V1))
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return V1 == V2;
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if (isa<InlineAsm>(V1) && isa<InlineAsm>(V2)) {
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const InlineAsm *IA1 = cast<InlineAsm>(V1);
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const InlineAsm *IA2 = cast<InlineAsm>(V2);
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return IA1->getAsmString() == IA2->getAsmString() &&
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IA1->getConstraintString() == IA2->getConstraintString();
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}
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// We enumerate constants globally and arguments, basic blocks or
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// instructions within the function they belong to.
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const Function *Domain1 = getDomain(V1);
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const Function *Domain2 = getDomain(V2);
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// The domains have to either be both NULL, or F1, F2.
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if (Domain1 != Domain2)
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if (Domain1 != F1 && Domain1 != F2)
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return false;
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IDMap &Map1 = Domains[Domain1];
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unsigned long &ID1 = Map1[V1];
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if (!ID1)
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ID1 = ++DomainCount[Domain1];
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IDMap &Map2 = Domains[Domain2];
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unsigned long &ID2 = Map2[V2];
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if (!ID2)
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ID2 = ++DomainCount[Domain2];
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return ID1 == ID2;
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}
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// Compare - test whether two basic blocks have equivalent behaviour.
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bool FunctionComparator::Compare(const BasicBlock *BB1, const BasicBlock *BB2) {
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BasicBlock::const_iterator F1I = BB1->begin(), F1E = BB1->end();
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BasicBlock::const_iterator F2I = BB2->begin(), F2E = BB2->end();
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do {
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if (!Enumerate(F1I, F2I))
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return false;
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if (const GetElementPtrInst *GEP1 = dyn_cast<GetElementPtrInst>(F1I)) {
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const GetElementPtrInst *GEP2 = dyn_cast<GetElementPtrInst>(F2I);
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if (!GEP2)
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return false;
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if (!Enumerate(GEP1->getPointerOperand(), GEP2->getPointerOperand()))
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return false;
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if (!isEquivalentGEP(GEP1, GEP2))
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return false;
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} else {
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if (!isEquivalentOperation(F1I, F2I))
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return false;
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assert(F1I->getNumOperands() == F2I->getNumOperands());
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for (unsigned i = 0, e = F1I->getNumOperands(); i != e; ++i) {
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Value *OpF1 = F1I->getOperand(i);
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Value *OpF2 = F2I->getOperand(i);
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if (!Enumerate(OpF1, OpF2))
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return false;
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if (OpF1->getValueID() != OpF2->getValueID() ||
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!isEquivalentType(OpF1->getType(), OpF2->getType()))
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return false;
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}
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}
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++F1I, ++F2I;
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} while (F1I != F1E && F2I != F2E);
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return F1I == F1E && F2I == F2E;
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}
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bool FunctionComparator::Compare() {
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// We need to recheck everything, but check the things that weren't included
|
|
// in the hash first.
|
|
|
|
if (F1->getAttributes() != F2->getAttributes())
|
|
return false;
|
|
|
|
if (F1->hasGC() != F2->hasGC())
|
|
return false;
|
|
|
|
if (F1->hasGC() && F1->getGC() != F2->getGC())
|
|
return false;
|
|
|
|
if (F1->hasSection() != F2->hasSection())
|
|
return false;
|
|
|
|
if (F1->hasSection() && F1->getSection() != F2->getSection())
|
|
return false;
|
|
|
|
if (F1->isVarArg() != F2->isVarArg())
|
|
return false;
|
|
|
|
// TODO: if it's internal and only used in direct calls, we could handle this
|
|
// case too.
|
|
if (F1->getCallingConv() != F2->getCallingConv())
|
|
return false;
|
|
|
|
if (!isEquivalentType(F1->getFunctionType(), F2->getFunctionType()))
|
|
return false;
|
|
|
|
assert(F1->arg_size() == F2->arg_size() &&
|
|
"Identical functions have a different number of args.");
|
|
|
|
// Visit the arguments so that they get enumerated in the order they're
|
|
// passed in.
|
|
for (Function::const_arg_iterator f1i = F1->arg_begin(),
|
|
f2i = F2->arg_begin(), f1e = F1->arg_end(); f1i != f1e; ++f1i, ++f2i) {
|
|
if (!Enumerate(f1i, f2i))
|
|
llvm_unreachable("Arguments repeat");
|
|
}
|
|
|
|
// We need to do an ordered walk since the actual ordering of the blocks in
|
|
// the linked list is immaterial. Our walk starts at the entry block for both
|
|
// functions, then takes each block from each terminator in order. As an
|
|
// artifact, this also means that unreachable blocks are ignored.
|
|
SmallVector<const BasicBlock *, 8> F1BBs, F2BBs;
|
|
SmallSet<const BasicBlock *, 128> VisitedBBs; // in terms of F1.
|
|
F1BBs.push_back(&F1->getEntryBlock());
|
|
F2BBs.push_back(&F2->getEntryBlock());
|
|
VisitedBBs.insert(F1BBs[0]);
|
|
while (!F1BBs.empty()) {
|
|
const BasicBlock *F1BB = F1BBs.pop_back_val();
|
|
const BasicBlock *F2BB = F2BBs.pop_back_val();
|
|
if (!Enumerate(F1BB, F2BB) || !Compare(F1BB, F2BB))
|
|
return false;
|
|
const TerminatorInst *F1TI = F1BB->getTerminator();
|
|
const TerminatorInst *F2TI = F2BB->getTerminator();
|
|
assert(F1TI->getNumSuccessors() == F2TI->getNumSuccessors());
|
|
for (unsigned i = 0, e = F1TI->getNumSuccessors(); i != e; ++i) {
|
|
if (!VisitedBBs.insert(F1TI->getSuccessor(i)))
|
|
continue;
|
|
F1BBs.push_back(F1TI->getSuccessor(i));
|
|
F2BBs.push_back(F2TI->getSuccessor(i));
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
// ===----------------------------------------------------------------------===
|
|
// Folding of functions
|
|
// ===----------------------------------------------------------------------===
|
|
|
|
// Cases:
|
|
// * F is external strong, G is external strong:
|
|
// turn G into a thunk to F (1)
|
|
// * F is external strong, G is external weak:
|
|
// turn G into a thunk to F (1)
|
|
// * F is external weak, G is external weak:
|
|
// unfoldable
|
|
// * F is external strong, G is internal:
|
|
// address of G taken:
|
|
// turn G into a thunk to F (1)
|
|
// address of G not taken:
|
|
// make G an alias to F (2)
|
|
// * F is internal, G is external weak
|
|
// address of F is taken:
|
|
// turn G into a thunk to F (1)
|
|
// address of F is not taken:
|
|
// make G an alias of F (2)
|
|
// * F is internal, G is internal:
|
|
// address of F and G are taken:
|
|
// turn G into a thunk to F (1)
|
|
// address of G is not taken:
|
|
// make G an alias to F (2)
|
|
//
|
|
// alias requires linkage == (external,local,weak) fallback to creating a thunk
|
|
// external means 'externally visible' linkage != (internal,private)
|
|
// internal means linkage == (internal,private)
|
|
// weak means linkage mayBeOverridable
|
|
// being external implies that the address is taken
|
|
//
|
|
// 1. turn G into a thunk to F
|
|
// 2. make G an alias to F
|
|
|
|
enum LinkageCategory {
|
|
ExternalStrong,
|
|
ExternalWeak,
|
|
Internal
|
|
};
|
|
|
|
static LinkageCategory categorize(const Function *F) {
|
|
switch (F->getLinkage()) {
|
|
case GlobalValue::InternalLinkage:
|
|
case GlobalValue::PrivateLinkage:
|
|
case GlobalValue::LinkerPrivateLinkage:
|
|
return Internal;
|
|
|
|
case GlobalValue::WeakAnyLinkage:
|
|
case GlobalValue::WeakODRLinkage:
|
|
case GlobalValue::ExternalWeakLinkage:
|
|
case GlobalValue::LinkerPrivateWeakLinkage:
|
|
return ExternalWeak;
|
|
|
|
case GlobalValue::ExternalLinkage:
|
|
case GlobalValue::AvailableExternallyLinkage:
|
|
case GlobalValue::LinkOnceAnyLinkage:
|
|
case GlobalValue::LinkOnceODRLinkage:
|
|
case GlobalValue::AppendingLinkage:
|
|
case GlobalValue::DLLImportLinkage:
|
|
case GlobalValue::DLLExportLinkage:
|
|
case GlobalValue::CommonLinkage:
|
|
return ExternalStrong;
|
|
}
|
|
|
|
llvm_unreachable("Unknown LinkageType.");
|
|
return ExternalWeak;
|
|
}
|
|
|
|
static void ThunkGToF(Function *F, Function *G) {
|
|
if (!G->mayBeOverridden()) {
|
|
// Redirect direct callers of G to F.
|
|
Constant *BitcastF = ConstantExpr::getBitCast(F, G->getType());
|
|
for (Value::use_iterator UI = G->use_begin(), UE = G->use_end();
|
|
UI != UE;) {
|
|
Value::use_iterator TheIter = UI;
|
|
++UI;
|
|
CallSite CS(*TheIter);
|
|
if (CS && CS.isCallee(TheIter))
|
|
TheIter.getUse().set(BitcastF);
|
|
}
|
|
}
|
|
|
|
Function *NewG = Function::Create(G->getFunctionType(), G->getLinkage(), "",
|
|
G->getParent());
|
|
BasicBlock *BB = BasicBlock::Create(F->getContext(), "", NewG);
|
|
|
|
SmallVector<Value *, 16> Args;
|
|
unsigned i = 0;
|
|
const FunctionType *FFTy = F->getFunctionType();
|
|
for (Function::arg_iterator AI = NewG->arg_begin(), AE = NewG->arg_end();
|
|
AI != AE; ++AI) {
|
|
if (FFTy->getParamType(i) == AI->getType()) {
|
|
Args.push_back(AI);
|
|
} else {
|
|
Args.push_back(new BitCastInst(AI, FFTy->getParamType(i), "", BB));
|
|
}
|
|
++i;
|
|
}
|
|
|
|
CallInst *CI = CallInst::Create(F, Args.begin(), Args.end(), "", BB);
|
|
CI->setTailCall();
|
|
CI->setCallingConv(F->getCallingConv());
|
|
if (NewG->getReturnType()->isVoidTy()) {
|
|
ReturnInst::Create(F->getContext(), BB);
|
|
} else if (CI->getType() != NewG->getReturnType()) {
|
|
Value *BCI = new BitCastInst(CI, NewG->getReturnType(), "", BB);
|
|
ReturnInst::Create(F->getContext(), BCI, BB);
|
|
} else {
|
|
ReturnInst::Create(F->getContext(), CI, BB);
|
|
}
|
|
|
|
NewG->copyAttributesFrom(G);
|
|
NewG->takeName(G);
|
|
G->replaceAllUsesWith(NewG);
|
|
G->eraseFromParent();
|
|
}
|
|
|
|
static void AliasGToF(Function *F, Function *G) {
|
|
// Darwin will trigger llvm_unreachable if asked to codegen an alias.
|
|
return ThunkGToF(F, G);
|
|
|
|
#if 0
|
|
if (!G->hasExternalLinkage() && !G->hasLocalLinkage() && !G->hasWeakLinkage())
|
|
return ThunkGToF(F, G);
|
|
|
|
GlobalAlias *GA = new GlobalAlias(
|
|
G->getType(), G->getLinkage(), "",
|
|
ConstantExpr::getBitCast(F, G->getType()), G->getParent());
|
|
F->setAlignment(std::max(F->getAlignment(), G->getAlignment()));
|
|
GA->takeName(G);
|
|
GA->setVisibility(G->getVisibility());
|
|
G->replaceAllUsesWith(GA);
|
|
G->eraseFromParent();
|
|
#endif
|
|
}
|
|
|
|
static bool fold(std::vector<Function *> &FnVec, unsigned i, unsigned j) {
|
|
Function *F = FnVec[i];
|
|
Function *G = FnVec[j];
|
|
|
|
LinkageCategory catF = categorize(F);
|
|
LinkageCategory catG = categorize(G);
|
|
|
|
if (catF == ExternalWeak || (catF == Internal && catG == ExternalStrong)) {
|
|
std::swap(FnVec[i], FnVec[j]);
|
|
std::swap(F, G);
|
|
std::swap(catF, catG);
|
|
}
|
|
|
|
switch (catF) {
|
|
case ExternalStrong:
|
|
switch (catG) {
|
|
case ExternalStrong:
|
|
case ExternalWeak:
|
|
ThunkGToF(F, G);
|
|
break;
|
|
case Internal:
|
|
if (G->hasAddressTaken())
|
|
ThunkGToF(F, G);
|
|
else
|
|
AliasGToF(F, G);
|
|
break;
|
|
}
|
|
break;
|
|
|
|
case ExternalWeak: {
|
|
assert(catG == ExternalWeak);
|
|
|
|
// Make them both thunks to the same internal function.
|
|
F->setAlignment(std::max(F->getAlignment(), G->getAlignment()));
|
|
Function *H = Function::Create(F->getFunctionType(), F->getLinkage(), "",
|
|
F->getParent());
|
|
H->copyAttributesFrom(F);
|
|
H->takeName(F);
|
|
F->replaceAllUsesWith(H);
|
|
|
|
ThunkGToF(F, G);
|
|
ThunkGToF(F, H);
|
|
|
|
F->setLinkage(GlobalValue::InternalLinkage);
|
|
} break;
|
|
|
|
case Internal:
|
|
switch (catG) {
|
|
case ExternalStrong:
|
|
llvm_unreachable(0);
|
|
// fall-through
|
|
case ExternalWeak:
|
|
if (F->hasAddressTaken())
|
|
ThunkGToF(F, G);
|
|
else
|
|
AliasGToF(F, G);
|
|
break;
|
|
case Internal: {
|
|
bool addrTakenF = F->hasAddressTaken();
|
|
bool addrTakenG = G->hasAddressTaken();
|
|
if (!addrTakenF && addrTakenG) {
|
|
std::swap(FnVec[i], FnVec[j]);
|
|
std::swap(F, G);
|
|
std::swap(addrTakenF, addrTakenG);
|
|
}
|
|
|
|
if (addrTakenF && addrTakenG) {
|
|
ThunkGToF(F, G);
|
|
} else {
|
|
assert(!addrTakenG);
|
|
AliasGToF(F, G);
|
|
}
|
|
} break;
|
|
} break;
|
|
}
|
|
|
|
++NumFunctionsMerged;
|
|
return true;
|
|
}
|
|
|
|
// ===----------------------------------------------------------------------===
|
|
// Pass definition
|
|
// ===----------------------------------------------------------------------===
|
|
|
|
bool MergeFunctions::runOnModule(Module &M) {
|
|
bool Changed = false;
|
|
|
|
std::map<unsigned long, std::vector<Function *> > FnMap;
|
|
|
|
for (Module::iterator F = M.begin(), E = M.end(); F != E; ++F) {
|
|
if (F->isDeclaration())
|
|
continue;
|
|
|
|
FnMap[ProfileFunction(F)].push_back(F);
|
|
}
|
|
|
|
TargetData *TD = getAnalysisIfAvailable<TargetData>();
|
|
|
|
bool LocalChanged;
|
|
do {
|
|
LocalChanged = false;
|
|
DEBUG(dbgs() << "size: " << FnMap.size() << "\n");
|
|
for (std::map<unsigned long, std::vector<Function *> >::iterator
|
|
I = FnMap.begin(), E = FnMap.end(); I != E; ++I) {
|
|
std::vector<Function *> &FnVec = I->second;
|
|
DEBUG(dbgs() << "hash (" << I->first << "): " << FnVec.size() << "\n");
|
|
|
|
for (int i = 0, e = FnVec.size(); i != e; ++i) {
|
|
for (int j = i + 1; j != e; ++j) {
|
|
bool isEqual = FunctionComparator(TD, FnVec[i], FnVec[j]).Compare();
|
|
|
|
DEBUG(dbgs() << " " << FnVec[i]->getName()
|
|
<< (isEqual ? " == " : " != ")
|
|
<< FnVec[j]->getName() << "\n");
|
|
|
|
if (isEqual) {
|
|
if (fold(FnVec, i, j)) {
|
|
LocalChanged = true;
|
|
FnVec.erase(FnVec.begin() + j);
|
|
--j, --e;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
}
|
|
Changed |= LocalChanged;
|
|
} while (LocalChanged);
|
|
|
|
return Changed;
|
|
}
|