#define DEBUG_TYPE "mergefunc"
#include "llvm/Transforms/IPO.h"
-#include "llvm/Constants.h"
-#include "llvm/IRBuilder.h"
-#include "llvm/InlineAsm.h"
-#include "llvm/Instructions.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Module.h"
-#include "llvm/Operator.h"
-#include "llvm/Pass.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/Statistic.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/InlineAsm.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Operator.h"
+#include "llvm/Pass.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/ValueHandle.h"
#include "llvm/Support/raw_ostream.h"
-#include "llvm/Target/TargetData.h"
#include <vector>
using namespace llvm;
STATISTIC(NumAliasesWritten, "Number of aliases generated");
STATISTIC(NumDoubleWeak, "Number of new functions created");
+/// Returns the type id for a type to be hashed. We turn pointer types into
+/// integers here because the actual compare logic below considers pointers and
+/// integers of the same size as equal.
+static Type::TypeID getTypeIDForHash(Type *Ty) {
+ if (Ty->isPointerTy())
+ return Type::IntegerTyID;
+ return Ty->getTypeID();
+}
+
/// Creates a hash-code for the function which is the same for any two
/// functions that will compare equal, without looking at the instructions
/// inside the function.
ID.AddInteger(F->getCallingConv());
ID.AddBoolean(F->hasGC());
ID.AddBoolean(FTy->isVarArg());
- ID.AddInteger(FTy->getReturnType()->getTypeID());
+ ID.AddInteger(getTypeIDForHash(FTy->getReturnType()));
for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
- ID.AddInteger(FTy->getParamType(i)->getTypeID());
+ ID.AddInteger(getTypeIDForHash(FTy->getParamType(i)));
return ID.ComputeHash();
}
namespace {
/// ComparableFunction - A struct that pairs together functions with a
-/// TargetData so that we can keep them together as elements in the DenseSet.
+/// DataLayout so that we can keep them together as elements in the DenseSet.
class ComparableFunction {
public:
static const ComparableFunction EmptyKey;
static const ComparableFunction TombstoneKey;
- static TargetData * const LookupOnly;
+ static DataLayout * const LookupOnly;
- ComparableFunction(Function *Func, TargetData *TD)
+ ComparableFunction(Function *Func, DataLayout *TD)
: Func(Func), Hash(profileFunction(Func)), TD(TD) {}
Function *getFunc() const { return Func; }
unsigned getHash() const { return Hash; }
- TargetData *getTD() const { return TD; }
+ DataLayout *getTD() const { return TD; }
// Drops AssertingVH reference to the function. Outside of debug mode, this
// does nothing.
AssertingVH<Function> Func;
unsigned Hash;
- TargetData *TD;
+ DataLayout *TD;
};
const ComparableFunction ComparableFunction::EmptyKey = ComparableFunction(0);
const ComparableFunction ComparableFunction::TombstoneKey =
ComparableFunction(1);
-TargetData *const ComparableFunction::LookupOnly = (TargetData*)(-1);
+DataLayout *const ComparableFunction::LookupOnly = (DataLayout*)(-1);
}
namespace {
/// FunctionComparator - Compares two functions to determine whether or not
-/// they will generate machine code with the same behaviour. TargetData is
+/// they will generate machine code with the same behaviour. DataLayout is
/// used if available. The comparator always fails conservatively (erring on the
/// side of claiming that two functions are different).
class FunctionComparator {
public:
- FunctionComparator(const TargetData *TD, const Function *F1,
+ FunctionComparator(const DataLayout *TD, const Function *F1,
const Function *F2)
: F1(F1), F2(F2), TD(TD) {}
// The two functions undergoing comparison.
const Function *F1, *F2;
- const TargetData *TD;
+ const DataLayout *TD;
DenseMap<const Value *, const Value *> id_map;
DenseSet<const Value *> seen_values;
// Any two pointers in the same address space are equivalent, intptr_t and
// pointers are equivalent. Otherwise, standard type equivalence rules apply.
-bool FunctionComparator::isEquivalentType(Type *Ty1,
- Type *Ty2) const {
+bool FunctionComparator::isEquivalentType(Type *Ty1, Type *Ty2) const {
+
+ PointerType *PTy1 = dyn_cast<PointerType>(Ty1);
+ PointerType *PTy2 = dyn_cast<PointerType>(Ty2);
+
+ if (TD) {
+ if (PTy1 && PTy1->getAddressSpace() == 0) Ty1 = TD->getIntPtrType(Ty1);
+ if (PTy2 && PTy2->getAddressSpace() == 0) Ty2 = TD->getIntPtrType(Ty2);
+ }
+
if (Ty1 == Ty2)
return true;
- if (Ty1->getTypeID() != Ty2->getTypeID()) {
- if (TD) {
- LLVMContext &Ctx = Ty1->getContext();
- if (isa<PointerType>(Ty1) && Ty2 == TD->getIntPtrType(Ctx)) return true;
- if (isa<PointerType>(Ty2) && Ty1 == TD->getIntPtrType(Ctx)) return true;
- }
+
+ if (Ty1->getTypeID() != Ty2->getTypeID())
return false;
- }
switch (Ty1->getTypeID()) {
default:
return true;
case Type::PointerTyID: {
- PointerType *PTy1 = cast<PointerType>(Ty1);
- PointerType *PTy2 = cast<PointerType>(Ty2);
+ assert(PTy1 && PTy2 && "Both types must be pointers here.");
return PTy1->getAddressSpace() == PTy2->getAddressSpace();
}
// Determine whether two GEP operations perform the same underlying arithmetic.
bool FunctionComparator::isEquivalentGEP(const GEPOperator *GEP1,
const GEPOperator *GEP2) {
- // When we have target data, we can reduce the GEP down to the value in bytes
- // added to the address.
- if (TD && GEP1->hasAllConstantIndices() && GEP2->hasAllConstantIndices()) {
- SmallVector<Value *, 8> Indices1(GEP1->idx_begin(), GEP1->idx_end());
- SmallVector<Value *, 8> Indices2(GEP2->idx_begin(), GEP2->idx_end());
- uint64_t Offset1 = TD->getIndexedOffset(GEP1->getPointerOperandType(),
- Indices1);
- uint64_t Offset2 = TD->getIndexedOffset(GEP2->getPointerOperandType(),
- Indices2);
- return Offset1 == Offset2;
+ unsigned AS = GEP1->getPointerAddressSpace();
+ if (AS != GEP2->getPointerAddressSpace())
+ return false;
+
+ if (TD) {
+ // When we have target data, we can reduce the GEP down to the value in bytes
+ // added to the address.
+ unsigned BitWidth = TD ? TD->getPointerSizeInBits(AS) : 1;
+ APInt Offset1(BitWidth, 0), Offset2(BitWidth, 0);
+ if (GEP1->accumulateConstantOffset(*TD, Offset1) &&
+ GEP2->accumulateConstantOffset(*TD, Offset2)) {
+ return Offset1 == Offset2;
+ }
}
if (GEP1->getPointerOperand()->getType() !=
if (!C2) return false;
// TODO: constant expressions with GEP or references to F1 or F2.
if (C1->isNullValue() && C2->isNullValue() &&
- isEquivalentType(C1->getType(), C2->getType()))
+ isEquivalentType(C1->getType(), C2->getType()))
return true;
// Try bitcasting C2 to C1's type. If the bitcast is legal and returns C1
// then they must have equal bit patterns.
/// to modify it.
FnSetType FnSet;
- /// TargetData for more accurate GEP comparisons. May be NULL.
- TargetData *TD;
+ /// DataLayout for more accurate GEP comparisons. May be NULL.
+ DataLayout *TD;
/// Whether or not the target supports global aliases.
bool HasGlobalAliases;
bool MergeFunctions::runOnModule(Module &M) {
bool Changed = false;
- TD = getAnalysisIfAvailable<TargetData>();
+ TD = getAnalysisIfAvailable<DataLayout>();
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
if (!I->isDeclaration() && !I->hasAvailableExternallyLinkage())
writeThunk(F, G);
}
+// Helper for writeThunk,
+// Selects proper bitcast operation,
+// but a bit simpler then CastInst::getCastOpcode.
+static Value* createCast(IRBuilder<false> &Builder, Value *V, Type *DestTy) {
+ Type *SrcTy = V->getType();
+ 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);
+}
+
// Replace G with a simple tail call to bitcast(F). Also replace direct uses
// of G with bitcast(F). Deletes G.
void MergeFunctions::writeThunk(Function *F, Function *G) {
FunctionType *FFTy = F->getFunctionType();
for (Function::arg_iterator AI = NewG->arg_begin(), AE = NewG->arg_end();
AI != AE; ++AI) {
- Args.push_back(Builder.CreateBitCast(AI, FFTy->getParamType(i)));
+ Args.push_back(createCast(Builder, (Value*)AI, FFTy->getParamType(i)));
++i;
}
if (NewG->getReturnType()->isVoidTy()) {
Builder.CreateRetVoid();
} else {
- Builder.CreateRet(Builder.CreateBitCast(CI, NewG->getReturnType()));
+ Builder.CreateRet(createCast(Builder, CI, NewG->getReturnType()));
}
NewG->copyAttributesFrom(G);
const ComparableFunction &OldF = *Result.first;
+ // Don't merge tiny functions, since it can just end up making the function
+ // larger.
+ // FIXME: Should still merge them if they are unnamed_addr and produce an
+ // alias.
+ if (NewF.getFunc()->size() == 1) {
+ if (NewF.getFunc()->front().size() <= 2) {
+ DEBUG(dbgs() << NewF.getFunc()->getName()
+ << " is to small to bother merging\n");
+ return false;
+ }
+ }
+
// Never thunk a strong function to a weak function.
assert(!OldF.getFunc()->mayBeOverridden() ||
NewF.getFunc()->mayBeOverridden());
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