#include "llvm/Transforms/IPO.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/ADT/STLExtras.h"
-#include "llvm/Constants.h"
-#include "llvm/InlineAsm.h"
-#include "llvm/Instructions.h"
-#include "llvm/LLVMContext.h"
-#include "llvm/Module.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/IRBuilder.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.
static unsigned profileFunction(const Function *F) {
- const FunctionType *FTy = F->getFunctionType();
+ FunctionType *FTy = F->getFunctionType();
FoldingSetNodeID ID;
ID.AddInteger(F->size());
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 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);
+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), IDMap1Count(0), IDMap2Count(0) {}
+ : F1(F1), F2(F2), TD(TD) {}
/// Test whether the two functions have equivalent behaviour.
bool compare();
}
/// Compare two Types, treating all pointer types as equal.
- bool isEquivalentType(const Type *Ty1, const Type *Ty2) const;
+ bool isEquivalentType(Type *Ty1, Type *Ty2) const;
// The two functions undergoing comparison.
const Function *F1, *F2;
- const TargetData *TD;
+ const DataLayout *TD;
- typedef DenseMap<const Value *, unsigned long> IDMap;
- IDMap Map1, Map2;
- unsigned long IDMap1Count, IDMap2Count;
+ 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(const Type *Ty1,
- const 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()) {
+ switch (Ty1->getTypeID()) {
default:
llvm_unreachable("Unknown type!");
// Fall through in Release mode.
case Type::IntegerTyID:
- case Type::OpaqueTyID:
case Type::VectorTyID:
// Ty1 == Ty2 would have returned true earlier.
return false;
return true;
case Type::PointerTyID: {
- const PointerType *PTy1 = cast<PointerType>(Ty1);
- const PointerType *PTy2 = cast<PointerType>(Ty2);
+ assert(PTy1 && PTy2 && "Both types must be pointers here.");
return PTy1->getAddressSpace() == PTy2->getAddressSpace();
}
case Type::StructTyID: {
- const StructType *STy1 = cast<StructType>(Ty1);
- const StructType *STy2 = cast<StructType>(Ty2);
+ StructType *STy1 = cast<StructType>(Ty1);
+ StructType *STy2 = cast<StructType>(Ty2);
if (STy1->getNumElements() != STy2->getNumElements())
return false;
}
case Type::FunctionTyID: {
- const FunctionType *FTy1 = cast<FunctionType>(Ty1);
- const FunctionType *FTy2 = cast<FunctionType>(Ty2);
+ FunctionType *FTy1 = cast<FunctionType>(Ty1);
+ FunctionType *FTy2 = cast<FunctionType>(Ty2);
if (FTy1->getNumParams() != FTy2->getNumParams() ||
FTy1->isVarArg() != FTy2->isVarArg())
return false;
}
case Type::ArrayTyID: {
-
const ArrayType *ATy1 = cast<ArrayType>(Ty1);
-
const ArrayType *ATy2 = cast<ArrayType>(Ty2);
+ ArrayType *ATy1 = cast<ArrayType>(Ty1);
+ ArrayType *ATy2 = cast<ArrayType>(Ty2);
return ATy1->getNumElements() == ATy2->getNumElements() &&
isEquivalentType(ATy1->getElementType(), ATy2->getElementType());
}
// Check special state that is a part of some instructions.
if (const LoadInst *LI = dyn_cast<LoadInst>(I1))
return LI->isVolatile() == cast<LoadInst>(I2)->isVolatile() &&
- LI->getAlignment() == cast<LoadInst>(I2)->getAlignment();
+ LI->getAlignment() == cast<LoadInst>(I2)->getAlignment() &&
+ LI->getOrdering() == cast<LoadInst>(I2)->getOrdering() &&
+ LI->getSynchScope() == cast<LoadInst>(I2)->getSynchScope();
if (const StoreInst *SI = dyn_cast<StoreInst>(I1))
return SI->isVolatile() == cast<StoreInst>(I2)->isVolatile() &&
- SI->getAlignment() == cast<StoreInst>(I2)->getAlignment();
+ SI->getAlignment() == cast<StoreInst>(I2)->getAlignment() &&
+ SI->getOrdering() == cast<StoreInst>(I2)->getOrdering() &&
+ SI->getSynchScope() == cast<StoreInst>(I2)->getSynchScope();
if (const CmpInst *CI = dyn_cast<CmpInst>(I1))
return CI->getPredicate() == cast<CmpInst>(I2)->getPredicate();
if (const CallInst *CI = dyn_cast<CallInst>(I1))
if (const InvokeInst *CI = dyn_cast<InvokeInst>(I1))
return CI->getCallingConv() == cast<InvokeInst>(I2)->getCallingConv() &&
CI->getAttributes() == cast<InvokeInst>(I2)->getAttributes();
- if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(I1)) {
- if (IVI->getNumIndices() != cast<InsertValueInst>(I2)->getNumIndices())
- return false;
- for (unsigned i = 0, e = IVI->getNumIndices(); i != e; ++i)
- if (IVI->idx_begin()[i] != cast<InsertValueInst>(I2)->idx_begin()[i])
- return false;
- return true;
- }
- if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I1)) {
- if (EVI->getNumIndices() != cast<ExtractValueInst>(I2)->getNumIndices())
- return false;
- for (unsigned i = 0, e = EVI->getNumIndices(); i != e; ++i)
- if (EVI->idx_begin()[i] != cast<ExtractValueInst>(I2)->idx_begin()[i])
- return false;
- return true;
- }
+ if (const InsertValueInst *IVI = dyn_cast<InsertValueInst>(I1))
+ return IVI->getIndices() == cast<InsertValueInst>(I2)->getIndices();
+ if (const ExtractValueInst *EVI = dyn_cast<ExtractValueInst>(I1))
+ return EVI->getIndices() == cast<ExtractValueInst>(I2)->getIndices();
+ if (const FenceInst *FI = dyn_cast<FenceInst>(I1))
+ return FI->getOrdering() == cast<FenceInst>(I2)->getOrdering() &&
+ FI->getSynchScope() == cast<FenceInst>(I2)->getSynchScope();
+ if (const AtomicCmpXchgInst *CXI = dyn_cast<AtomicCmpXchgInst>(I1))
+ return CXI->isVolatile() == cast<AtomicCmpXchgInst>(I2)->isVolatile() &&
+ CXI->getOrdering() == cast<AtomicCmpXchgInst>(I2)->getOrdering() &&
+ CXI->getSynchScope() == cast<AtomicCmpXchgInst>(I2)->getSynchScope();
+ if (const AtomicRMWInst *RMWI = dyn_cast<AtomicRMWInst>(I1))
+ return RMWI->getOperation() == cast<AtomicRMWInst>(I2)->getOperation() &&
+ RMWI->isVolatile() == cast<AtomicRMWInst>(I2)->isVolatile() &&
+ RMWI->getOrdering() == cast<AtomicRMWInst>(I2)->getOrdering() &&
+ RMWI->getSynchScope() == cast<AtomicRMWInst>(I2)->getSynchScope();
return true;
}
// 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.data(), Indices1.size());
- uint64_t Offset2 = TD->getIndexedOffset(GEP2->getPointerOperandType(),
- Indices2.data(), Indices2.size());
- 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.
if (isa<InlineAsm>(V1) || isa<InlineAsm>(V2))
return V1 == V2;
- unsigned long &ID1 = Map1[V1];
- if (!ID1)
- ID1 = ++IDMap1Count;
-
- unsigned long &ID2 = Map2[V2];
- if (!ID2)
- ID2 = ++IDMap2Count;
+ // Check that V1 maps to V2. If we find a value that V1 maps to then we simply
+ // check whether it's equal to V2. When there is no mapping then we need to
+ // ensure that V2 isn't already equivalent to something else. For this
+ // purpose, we track the V2 values in a set.
- return ID1 == ID2;
+ const Value *&map_elem = id_map[V1];
+ if (map_elem)
+ return map_elem == V2;
+ if (!seen_values.insert(V2).second)
+ return false;
+ map_elem = V2;
+ return true;
}
// Test whether two basic blocks have equivalent behaviour.
/// 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())
return true;
if (!LHS.getFunc() || !RHS.getFunc())
return false;
+
+ // One of these is a special "underlying pointer comparison only" object.
+ if (LHS.getTD() == ComparableFunction::LookupOnly ||
+ RHS.getTD() == ComparableFunction::LookupOnly)
+ return false;
+
assert(LHS.getTD() == RHS.getTD() &&
"Comparing functions for different targets");
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) {
SmallVector<Value *, 16> Args;
unsigned i = 0;
- const FunctionType *FFTy = F->getFunctionType();
+ 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;
}
- CallInst *CI = Builder.CreateCall(F, Args.begin(), Args.end());
+ CallInst *CI = Builder.CreateCall(F, Args);
CI->setTailCall();
CI->setCallingConv(F->getCallingConv());
if (NewG->getReturnType()->isVoidTy()) {
Builder.CreateRetVoid();
} else {
- Builder.CreateRet(Builder.CreateBitCast(CI, NewG->getReturnType()));
+ Builder.CreateRet(createCast(Builder, CI, NewG->getReturnType()));
}
NewG->copyAttributesFrom(G);
// that was already inserted.
bool MergeFunctions::insert(ComparableFunction &NewF) {
std::pair<FnSetType::iterator, bool> Result = FnSet.insert(NewF);
- if (Result.second)
+ if (Result.second) {
+ DEBUG(dbgs() << "Inserting as unique: " << NewF.getFunc()->getName() << '\n');
return false;
+ }
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());
// Remove a function from FnSet. If it was already in FnSet, add it to Deferred
// so that we'll look at it in the next round.
void MergeFunctions::remove(Function *F) {
- ComparableFunction CF = ComparableFunction(F, TD);
+ // We need to make sure we remove F, not a function "equal" to F per the
+ // function equality comparator.
+ //
+ // The special "lookup only" ComparableFunction bypasses the expensive
+ // function comparison in favour of a pointer comparison on the underlying
+ // Function*'s.
+ ComparableFunction CF = ComparableFunction(F, ComparableFunction::LookupOnly);
if (FnSet.erase(CF)) {
+ DEBUG(dbgs() << "Removed " << F->getName() << " from set and deferred it.\n");
Deferred.push_back(F);
}
}
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