2008-11-02 13:52:50 +08:00
|
|
|
//===- 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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|
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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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//
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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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|
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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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//
|
2010-05-13 13:48:45 +08:00
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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.
|
2008-11-02 13:52:50 +08:00
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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
|
2010-08-08 13:04:23 +08:00
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|
|
// and call, this is irrelevant, and we'd like to fold such functions.
|
2008-11-02 13:52:50 +08:00
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|
|
//
|
2010-08-02 13:23:03 +08:00
|
|
|
// * switch from n^2 pair-wise comparisons to an n-way comparison for each
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|
|
// bucket.
|
2010-05-13 13:48:45 +08:00
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|
|
//
|
2010-08-08 13:04:23 +08:00
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|
|
// * be smarter about bitcasts.
|
2010-05-13 13:48:45 +08:00
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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
|
2010-08-08 13:04:23 +08:00
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|
|
// other doesn't. We should learn to look through bitcasts.
|
2010-05-13 13:48:45 +08:00
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|
|
//
|
2008-11-02 13:52:50 +08:00
|
|
|
//===----------------------------------------------------------------------===//
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|
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|
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|
|
#include "llvm/Transforms/IPO.h"
|
2012-12-04 00:50:05 +08:00
|
|
|
#include "llvm/ADT/DenseSet.h"
|
|
|
|
#include "llvm/ADT/FoldingSet.h"
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|
|
#include "llvm/ADT/STLExtras.h"
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|
|
|
#include "llvm/ADT/SmallSet.h"
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|
|
#include "llvm/ADT/Statistic.h"
|
2014-03-04 19:01:28 +08:00
|
|
|
#include "llvm/IR/CallSite.h"
|
2013-01-02 19:36:10 +08:00
|
|
|
#include "llvm/IR/Constants.h"
|
|
|
|
#include "llvm/IR/DataLayout.h"
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|
|
#include "llvm/IR/IRBuilder.h"
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|
|
|
#include "llvm/IR/InlineAsm.h"
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|
|
|
#include "llvm/IR/Instructions.h"
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|
|
#include "llvm/IR/LLVMContext.h"
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|
|
#include "llvm/IR/Module.h"
|
|
|
|
#include "llvm/IR/Operator.h"
|
2014-03-04 19:17:44 +08:00
|
|
|
#include "llvm/IR/ValueHandle.h"
|
2008-11-02 13:52:50 +08:00
|
|
|
#include "llvm/Pass.h"
|
|
|
|
#include "llvm/Support/Debug.h"
|
2009-07-12 04:10:48 +08:00
|
|
|
#include "llvm/Support/ErrorHandling.h"
|
2009-07-25 08:23:56 +08:00
|
|
|
#include "llvm/Support/raw_ostream.h"
|
2010-08-31 16:29:37 +08:00
|
|
|
#include <vector>
|
2008-11-02 13:52:50 +08:00
|
|
|
using namespace llvm;
|
|
|
|
|
2014-04-22 10:55:47 +08:00
|
|
|
#define DEBUG_TYPE "mergefunc"
|
|
|
|
|
2008-11-02 13:52:50 +08:00
|
|
|
STATISTIC(NumFunctionsMerged, "Number of functions merged");
|
2010-09-07 09:42:10 +08:00
|
|
|
STATISTIC(NumThunksWritten, "Number of thunks generated");
|
2011-01-25 16:56:50 +08:00
|
|
|
STATISTIC(NumAliasesWritten, "Number of aliases generated");
|
2010-09-07 09:42:10 +08:00
|
|
|
STATISTIC(NumDoubleWeak, "Number of new functions created");
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2013-04-20 07:06:44 +08:00
|
|
|
/// 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();
|
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// 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) {
|
2011-07-18 12:54:35 +08:00
|
|
|
FunctionType *FTy = F->getFunctionType();
|
2010-09-05 16:22:49 +08:00
|
|
|
|
|
|
|
FoldingSetNodeID ID;
|
|
|
|
ID.AddInteger(F->size());
|
|
|
|
ID.AddInteger(F->getCallingConv());
|
|
|
|
ID.AddBoolean(F->hasGC());
|
|
|
|
ID.AddBoolean(FTy->isVarArg());
|
2013-04-20 07:06:44 +08:00
|
|
|
ID.AddInteger(getTypeIDForHash(FTy->getReturnType()));
|
2010-09-05 16:22:49 +08:00
|
|
|
for (unsigned i = 0, e = FTy->getNumParams(); i != e; ++i)
|
2013-04-20 07:06:44 +08:00
|
|
|
ID.AddInteger(getTypeIDForHash(FTy->getParamType(i)));
|
2010-09-05 16:22:49 +08:00
|
|
|
return ID.ComputeHash();
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2010-09-07 09:42:10 +08:00
|
|
|
namespace {
|
|
|
|
|
2011-01-28 16:19:00 +08:00
|
|
|
/// ComparableFunction - A struct that pairs together functions with a
|
2012-10-09 00:38:25 +08:00
|
|
|
/// DataLayout so that we can keep them together as elements in the DenseSet.
|
2010-09-05 16:22:49 +08:00
|
|
|
class ComparableFunction {
|
|
|
|
public:
|
2010-09-05 17:00:32 +08:00
|
|
|
static const ComparableFunction EmptyKey;
|
|
|
|
static const ComparableFunction TombstoneKey;
|
2012-10-09 00:38:25 +08:00
|
|
|
static DataLayout * const LookupOnly;
|
2010-09-05 17:00:32 +08:00
|
|
|
|
2014-02-25 07:12:18 +08:00
|
|
|
ComparableFunction(Function *Func, const DataLayout *DL)
|
2014-02-21 08:06:31 +08:00
|
|
|
: Func(Func), Hash(profileFunction(Func)), DL(DL) {}
|
2010-09-05 16:22:49 +08:00
|
|
|
|
2010-09-05 17:00:32 +08:00
|
|
|
Function *getFunc() const { return Func; }
|
|
|
|
unsigned getHash() const { return Hash; }
|
2014-02-25 07:12:18 +08:00
|
|
|
const DataLayout *getDataLayout() const { return DL; }
|
2010-09-05 16:22:49 +08:00
|
|
|
|
2010-09-05 17:00:32 +08:00
|
|
|
// Drops AssertingVH reference to the function. Outside of debug mode, this
|
|
|
|
// does nothing.
|
|
|
|
void release() {
|
|
|
|
assert(Func &&
|
|
|
|
"Attempted to release function twice, or release empty/tombstone!");
|
2014-04-25 13:29:35 +08:00
|
|
|
Func = nullptr;
|
2010-09-05 16:22:49 +08:00
|
|
|
}
|
2010-09-05 17:00:32 +08:00
|
|
|
|
|
|
|
private:
|
|
|
|
explicit ComparableFunction(unsigned Hash)
|
2014-04-25 13:29:35 +08:00
|
|
|
: Func(nullptr), Hash(Hash), DL(nullptr) {}
|
2010-09-05 17:00:32 +08:00
|
|
|
|
|
|
|
AssertingVH<Function> Func;
|
|
|
|
unsigned Hash;
|
2014-02-25 07:12:18 +08:00
|
|
|
const DataLayout *DL;
|
2010-09-05 16:22:49 +08:00
|
|
|
};
|
|
|
|
|
2010-09-05 17:00:32 +08:00
|
|
|
const ComparableFunction ComparableFunction::EmptyKey = ComparableFunction(0);
|
|
|
|
const ComparableFunction ComparableFunction::TombstoneKey =
|
|
|
|
ComparableFunction(1);
|
2012-10-09 00:38:25 +08:00
|
|
|
DataLayout *const ComparableFunction::LookupOnly = (DataLayout*)(-1);
|
2010-09-05 17:00:32 +08:00
|
|
|
|
2010-09-07 09:42:10 +08:00
|
|
|
}
|
2010-09-05 17:00:32 +08:00
|
|
|
|
|
|
|
namespace llvm {
|
|
|
|
template <>
|
|
|
|
struct DenseMapInfo<ComparableFunction> {
|
|
|
|
static ComparableFunction getEmptyKey() {
|
|
|
|
return ComparableFunction::EmptyKey;
|
|
|
|
}
|
|
|
|
static ComparableFunction getTombstoneKey() {
|
|
|
|
return ComparableFunction::TombstoneKey;
|
|
|
|
}
|
|
|
|
static unsigned getHashValue(const ComparableFunction &CF) {
|
|
|
|
return CF.getHash();
|
|
|
|
}
|
|
|
|
static bool isEqual(const ComparableFunction &LHS,
|
|
|
|
const ComparableFunction &RHS);
|
|
|
|
};
|
|
|
|
}
|
|
|
|
|
|
|
|
namespace {
|
|
|
|
|
2010-08-08 13:04:23 +08:00
|
|
|
/// FunctionComparator - Compares two functions to determine whether or not
|
2012-10-09 00:38:25 +08:00
|
|
|
/// they will generate machine code with the same behaviour. DataLayout is
|
2010-08-08 13:04:23 +08:00
|
|
|
/// used if available. The comparator always fails conservatively (erring on the
|
|
|
|
/// side of claiming that two functions are different).
|
2010-08-02 13:23:03 +08:00
|
|
|
class FunctionComparator {
|
|
|
|
public:
|
2014-02-21 08:06:31 +08:00
|
|
|
FunctionComparator(const DataLayout *DL, const Function *F1,
|
2010-08-31 13:53:05 +08:00
|
|
|
const Function *F2)
|
2014-02-21 08:06:31 +08:00
|
|
|
: F1(F1), F2(F2), DL(DL) {}
|
2010-08-02 13:23:03 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Test whether the two functions have equivalent behaviour.
|
|
|
|
bool compare();
|
2010-08-02 13:23:03 +08:00
|
|
|
|
|
|
|
private:
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Test whether two basic blocks have equivalent behaviour.
|
|
|
|
bool compare(const BasicBlock *BB1, const BasicBlock *BB2);
|
2010-08-02 13:23:03 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Assign or look up previously assigned numbers for the two values, and
|
|
|
|
/// return whether the numbers are equal. Numbers are assigned in the order
|
|
|
|
/// visited.
|
|
|
|
bool enumerate(const Value *V1, const Value *V2);
|
2010-08-02 13:23:03 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Compare two Instructions for equivalence, similar to
|
|
|
|
/// Instruction::isSameOperationAs but with modifications to the type
|
2010-08-08 13:04:23 +08:00
|
|
|
/// comparison.
|
2010-08-02 13:23:03 +08:00
|
|
|
bool isEquivalentOperation(const Instruction *I1,
|
|
|
|
const Instruction *I2) const;
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Compare two GEPs for equivalent pointer arithmetic.
|
2010-08-02 13:23:03 +08:00
|
|
|
bool isEquivalentGEP(const GEPOperator *GEP1, const GEPOperator *GEP2);
|
|
|
|
bool isEquivalentGEP(const GetElementPtrInst *GEP1,
|
2010-08-08 13:04:23 +08:00
|
|
|
const GetElementPtrInst *GEP2) {
|
2010-08-02 13:23:03 +08:00
|
|
|
return isEquivalentGEP(cast<GEPOperator>(GEP1), cast<GEPOperator>(GEP2));
|
|
|
|
}
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2014-03-13 19:54:50 +08:00
|
|
|
/// cmpType - compares two types,
|
|
|
|
/// defines total ordering among the types set.
|
|
|
|
///
|
|
|
|
/// Return values:
|
|
|
|
/// 0 if types are equal,
|
|
|
|
/// -1 if Left is less than Right,
|
|
|
|
/// +1 if Left is greater than Right.
|
|
|
|
///
|
|
|
|
/// Description:
|
|
|
|
/// Comparison is broken onto stages. Like in lexicographical comparison
|
|
|
|
/// stage coming first has higher priority.
|
|
|
|
/// On each explanation stage keep in mind total ordering properties.
|
|
|
|
///
|
2014-03-14 16:17:19 +08:00
|
|
|
/// 0. Before comparison we coerce pointer types of 0 address space to
|
|
|
|
/// integer.
|
2014-03-13 19:54:50 +08:00
|
|
|
/// We also don't bother with same type at left and right, so
|
|
|
|
/// just return 0 in this case.
|
|
|
|
///
|
|
|
|
/// 1. If types are of different kind (different type IDs).
|
|
|
|
/// Return result of type IDs comparison, treating them as numbers.
|
|
|
|
/// 2. If types are vectors or integers, compare Type* values as numbers.
|
|
|
|
/// 3. Types has same ID, so check whether they belongs to the next group:
|
|
|
|
/// * Void
|
|
|
|
/// * Float
|
|
|
|
/// * Double
|
|
|
|
/// * X86_FP80
|
|
|
|
/// * FP128
|
|
|
|
/// * PPC_FP128
|
|
|
|
/// * Label
|
|
|
|
/// * Metadata
|
|
|
|
/// If so - return 0, yes - we can treat these types as equal only because
|
|
|
|
/// their IDs are same.
|
|
|
|
/// 4. If Left and Right are pointers, return result of address space
|
|
|
|
/// comparison (numbers comparison). We can treat pointer types of same
|
|
|
|
/// address space as equal.
|
|
|
|
/// 5. If types are complex.
|
|
|
|
/// Then both Left and Right are to be expanded and their element types will
|
|
|
|
/// be checked with the same way. If we get Res != 0 on some stage, return it.
|
|
|
|
/// Otherwise return 0.
|
|
|
|
/// 6. For all other cases put llvm_unreachable.
|
|
|
|
int cmpType(Type *TyL, Type *TyR) const;
|
|
|
|
|
|
|
|
bool isEquivalentType(Type *Ty1, Type *Ty2) const {
|
|
|
|
return cmpType(Ty1, Ty2) == 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
int cmpNumbers(uint64_t L, uint64_t R) const;
|
2010-08-02 13:23:03 +08:00
|
|
|
|
|
|
|
// The two functions undergoing comparison.
|
2010-08-31 13:53:05 +08:00
|
|
|
const Function *F1, *F2;
|
2010-08-02 13:23:03 +08:00
|
|
|
|
2014-02-21 08:06:31 +08:00
|
|
|
const DataLayout *DL;
|
2010-08-02 13:23:03 +08:00
|
|
|
|
2011-02-20 16:11:03 +08:00
|
|
|
DenseMap<const Value *, const Value *> id_map;
|
|
|
|
DenseSet<const Value *> seen_values;
|
2010-08-02 13:23:03 +08:00
|
|
|
};
|
2011-01-28 15:36:21 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
}
|
|
|
|
|
2014-03-13 19:54:50 +08:00
|
|
|
int FunctionComparator::cmpNumbers(uint64_t L, uint64_t R) const {
|
|
|
|
if (L < R) return -1;
|
|
|
|
if (L > R) return 1;
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/// cmpType - compares two types,
|
|
|
|
/// defines total ordering among the types set.
|
|
|
|
/// See method declaration comments for more details.
|
|
|
|
int FunctionComparator::cmpType(Type *TyL, Type *TyR) const {
|
2013-11-27 00:11:03 +08:00
|
|
|
|
2014-03-14 16:48:52 +08:00
|
|
|
PointerType *PTyL = dyn_cast<PointerType>(TyL);
|
|
|
|
PointerType *PTyR = dyn_cast<PointerType>(TyR);
|
2013-11-27 00:11:03 +08:00
|
|
|
|
2014-02-21 08:06:31 +08:00
|
|
|
if (DL) {
|
2014-03-14 16:48:52 +08:00
|
|
|
if (PTyL && PTyL->getAddressSpace() == 0) TyL = DL->getIntPtrType(TyL);
|
|
|
|
if (PTyR && PTyR->getAddressSpace() == 0) TyR = DL->getIntPtrType(TyR);
|
2013-11-27 00:11:03 +08:00
|
|
|
}
|
|
|
|
|
2014-03-13 19:54:50 +08:00
|
|
|
if (TyL == TyR)
|
|
|
|
return 0;
|
2013-11-10 09:44:37 +08:00
|
|
|
|
2014-03-13 19:54:50 +08:00
|
|
|
if (int Res = cmpNumbers(TyL->getTypeID(), TyR->getTypeID()))
|
|
|
|
return Res;
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2014-03-13 19:54:50 +08:00
|
|
|
switch (TyL->getTypeID()) {
|
2010-05-13 13:48:45 +08:00
|
|
|
default:
|
|
|
|
llvm_unreachable("Unknown type!");
|
2010-07-07 15:48:00 +08:00
|
|
|
// Fall through in Release mode.
|
2010-05-13 13:48:45 +08:00
|
|
|
case Type::IntegerTyID:
|
2011-01-26 16:50:18 +08:00
|
|
|
case Type::VectorTyID:
|
2014-03-13 19:54:50 +08:00
|
|
|
// TyL == TyR would have returned true earlier.
|
|
|
|
return cmpNumbers((uint64_t)TyL, (uint64_t)TyR);
|
2010-05-13 13:48:45 +08:00
|
|
|
|
2009-06-12 16:04:51 +08:00
|
|
|
case Type::VoidTyID:
|
|
|
|
case Type::FloatTyID:
|
|
|
|
case Type::DoubleTyID:
|
|
|
|
case Type::X86_FP80TyID:
|
|
|
|
case Type::FP128TyID:
|
|
|
|
case Type::PPC_FP128TyID:
|
|
|
|
case Type::LabelTyID:
|
|
|
|
case Type::MetadataTyID:
|
2014-03-13 19:54:50 +08:00
|
|
|
return 0;
|
2009-06-12 16:04:51 +08:00
|
|
|
|
|
|
|
case Type::PointerTyID: {
|
2014-03-14 16:48:52 +08:00
|
|
|
assert(PTyL && PTyR && "Both types must be pointers here.");
|
|
|
|
return cmpNumbers(PTyL->getAddressSpace(), PTyR->getAddressSpace());
|
2009-06-12 16:04:51 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
case Type::StructTyID: {
|
2014-03-14 16:48:52 +08:00
|
|
|
StructType *STyL = cast<StructType>(TyL);
|
|
|
|
StructType *STyR = cast<StructType>(TyR);
|
|
|
|
if (STyL->getNumElements() != STyR->getNumElements())
|
|
|
|
return cmpNumbers(STyL->getNumElements(), STyR->getNumElements());
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2014-03-14 16:48:52 +08:00
|
|
|
if (STyL->isPacked() != STyR->isPacked())
|
|
|
|
return cmpNumbers(STyL->isPacked(), STyR->isPacked());
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2014-03-14 16:48:52 +08:00
|
|
|
for (unsigned i = 0, e = STyL->getNumElements(); i != e; ++i) {
|
|
|
|
if (int Res = cmpType(STyL->getElementType(i),
|
|
|
|
STyR->getElementType(i)))
|
2014-03-13 19:54:50 +08:00
|
|
|
return Res;
|
2009-06-12 16:04:51 +08:00
|
|
|
}
|
2014-03-13 19:54:50 +08:00
|
|
|
return 0;
|
2009-06-12 16:04:51 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
case Type::FunctionTyID: {
|
2014-03-14 16:48:52 +08:00
|
|
|
FunctionType *FTyL = cast<FunctionType>(TyL);
|
|
|
|
FunctionType *FTyR = cast<FunctionType>(TyR);
|
|
|
|
if (FTyL->getNumParams() != FTyR->getNumParams())
|
|
|
|
return cmpNumbers(FTyL->getNumParams(), FTyR->getNumParams());
|
2014-03-13 19:54:50 +08:00
|
|
|
|
2014-03-14 16:48:52 +08:00
|
|
|
if (FTyL->isVarArg() != FTyR->isVarArg())
|
|
|
|
return cmpNumbers(FTyL->isVarArg(), FTyR->isVarArg());
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2014-03-14 16:48:52 +08:00
|
|
|
if (int Res = cmpType(FTyL->getReturnType(), FTyR->getReturnType()))
|
2014-03-13 19:54:50 +08:00
|
|
|
return Res;
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2014-03-14 16:48:52 +08:00
|
|
|
for (unsigned i = 0, e = FTyL->getNumParams(); i != e; ++i) {
|
|
|
|
if (int Res = cmpType(FTyL->getParamType(i), FTyR->getParamType(i)))
|
2014-03-13 19:54:50 +08:00
|
|
|
return Res;
|
2009-06-12 16:04:51 +08:00
|
|
|
}
|
2014-03-13 19:54:50 +08:00
|
|
|
return 0;
|
2009-06-12 16:04:51 +08:00
|
|
|
}
|
|
|
|
|
2010-07-16 14:31:12 +08:00
|
|
|
case Type::ArrayTyID: {
|
2014-03-14 16:48:52 +08:00
|
|
|
ArrayType *ATyL = cast<ArrayType>(TyL);
|
|
|
|
ArrayType *ATyR = cast<ArrayType>(TyR);
|
|
|
|
if (ATyL->getNumElements() != ATyR->getNumElements())
|
|
|
|
return cmpNumbers(ATyL->getNumElements(), ATyR->getNumElements());
|
|
|
|
return cmpType(ATyL->getElementType(), ATyR->getElementType());
|
2009-06-12 16:04:51 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Determine whether the two operations are the same except that pointer-to-A
|
|
|
|
// and pointer-to-B are equivalent. This should be kept in sync with
|
|
|
|
// Instruction::isSameOperationAs.
|
2010-08-02 13:23:03 +08:00
|
|
|
bool FunctionComparator::isEquivalentOperation(const Instruction *I1,
|
|
|
|
const Instruction *I2) const {
|
2011-02-06 13:04:00 +08:00
|
|
|
// Differences from Instruction::isSameOperationAs:
|
|
|
|
// * replace type comparison with calls to isEquivalentType.
|
|
|
|
// * we test for I->hasSameSubclassOptionalData (nuw/nsw/tail) at the top
|
|
|
|
// * because of the above, we don't test for the tail bit on calls later on
|
2009-06-12 16:04:51 +08:00
|
|
|
if (I1->getOpcode() != I2->getOpcode() ||
|
|
|
|
I1->getNumOperands() != I2->getNumOperands() ||
|
2009-08-26 06:11:20 +08:00
|
|
|
!isEquivalentType(I1->getType(), I2->getType()) ||
|
|
|
|
!I1->hasSameSubclassOptionalData(I2))
|
2009-06-12 16:04:51 +08:00
|
|
|
return false;
|
|
|
|
|
|
|
|
// We have two instructions of identical opcode and #operands. Check to see
|
|
|
|
// if all operands are the same type
|
|
|
|
for (unsigned i = 0, e = I1->getNumOperands(); i != e; ++i)
|
|
|
|
if (!isEquivalentType(I1->getOperand(i)->getType(),
|
|
|
|
I2->getOperand(i)->getType()))
|
|
|
|
return false;
|
|
|
|
|
|
|
|
// 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() &&
|
2011-08-16 06:16:46 +08:00
|
|
|
LI->getAlignment() == cast<LoadInst>(I2)->getAlignment() &&
|
|
|
|
LI->getOrdering() == cast<LoadInst>(I2)->getOrdering() &&
|
|
|
|
LI->getSynchScope() == cast<LoadInst>(I2)->getSynchScope();
|
2009-06-12 16:04:51 +08:00
|
|
|
if (const StoreInst *SI = dyn_cast<StoreInst>(I1))
|
|
|
|
return SI->isVolatile() == cast<StoreInst>(I2)->isVolatile() &&
|
2011-08-16 06:16:46 +08:00
|
|
|
SI->getAlignment() == cast<StoreInst>(I2)->getAlignment() &&
|
|
|
|
SI->getOrdering() == cast<StoreInst>(I2)->getOrdering() &&
|
|
|
|
SI->getSynchScope() == cast<StoreInst>(I2)->getSynchScope();
|
2009-06-12 16:04:51 +08:00
|
|
|
if (const CmpInst *CI = dyn_cast<CmpInst>(I1))
|
|
|
|
return CI->getPredicate() == cast<CmpInst>(I2)->getPredicate();
|
|
|
|
if (const CallInst *CI = dyn_cast<CallInst>(I1))
|
2011-02-06 13:04:00 +08:00
|
|
|
return CI->getCallingConv() == cast<CallInst>(I2)->getCallingConv() &&
|
2011-01-26 17:23:19 +08:00
|
|
|
CI->getAttributes() == cast<CallInst>(I2)->getAttributes();
|
2009-06-12 16:04:51 +08:00
|
|
|
if (const InvokeInst *CI = dyn_cast<InvokeInst>(I1))
|
|
|
|
return CI->getCallingConv() == cast<InvokeInst>(I2)->getCallingConv() &&
|
2011-01-26 17:23:19 +08:00
|
|
|
CI->getAttributes() == cast<InvokeInst>(I2)->getAttributes();
|
2011-07-29 11:05:32 +08:00
|
|
|
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() &&
|
2014-03-11 18:48:52 +08:00
|
|
|
CXI->getSuccessOrdering() ==
|
|
|
|
cast<AtomicCmpXchgInst>(I2)->getSuccessOrdering() &&
|
|
|
|
CXI->getFailureOrdering() ==
|
|
|
|
cast<AtomicCmpXchgInst>(I2)->getFailureOrdering() &&
|
2011-07-29 11:05:32 +08:00
|
|
|
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();
|
2009-06-12 16:04:51 +08:00
|
|
|
|
|
|
|
return true;
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Determine whether two GEP operations perform the same underlying arithmetic.
|
2010-08-02 13:23:03 +08:00
|
|
|
bool FunctionComparator::isEquivalentGEP(const GEPOperator *GEP1,
|
|
|
|
const GEPOperator *GEP2) {
|
2013-11-10 09:44:37 +08:00
|
|
|
unsigned AS = GEP1->getPointerAddressSpace();
|
|
|
|
if (AS != GEP2->getPointerAddressSpace())
|
|
|
|
return false;
|
|
|
|
|
2014-02-21 08:06:31 +08:00
|
|
|
if (DL) {
|
2013-11-10 09:44:37 +08:00
|
|
|
// When we have target data, we can reduce the GEP down to the value in bytes
|
|
|
|
// added to the address.
|
2014-02-21 08:06:31 +08:00
|
|
|
unsigned BitWidth = DL ? DL->getPointerSizeInBits(AS) : 1;
|
2013-11-10 09:44:37 +08:00
|
|
|
APInt Offset1(BitWidth, 0), Offset2(BitWidth, 0);
|
2014-02-21 08:06:31 +08:00
|
|
|
if (GEP1->accumulateConstantOffset(*DL, Offset1) &&
|
|
|
|
GEP2->accumulateConstantOffset(*DL, Offset2)) {
|
2013-11-10 09:44:37 +08:00
|
|
|
return Offset1 == Offset2;
|
|
|
|
}
|
2010-05-13 13:48:45 +08:00
|
|
|
}
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
if (GEP1->getPointerOperand()->getType() !=
|
|
|
|
GEP2->getPointerOperand()->getType())
|
|
|
|
return false;
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
if (GEP1->getNumOperands() != GEP2->getNumOperands())
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
for (unsigned i = 0, e = GEP1->getNumOperands(); i != e; ++i) {
|
2011-01-28 16:43:14 +08:00
|
|
|
if (!enumerate(GEP1->getOperand(i), GEP2->getOperand(i)))
|
2010-05-13 13:48:45 +08:00
|
|
|
return false;
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
return true;
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Compare two values used by the two functions under pair-wise comparison. If
|
|
|
|
// this is the first time the values are seen, they're added to the mapping so
|
|
|
|
// that we will detect mismatches on next use.
|
|
|
|
bool FunctionComparator::enumerate(const Value *V1, const Value *V2) {
|
2010-08-02 13:23:03 +08:00
|
|
|
// Check for function @f1 referring to itself and function @f2 referring to
|
|
|
|
// itself, or referring to each other, or both referring to either of them.
|
|
|
|
// They're all equivalent if the two functions are otherwise equivalent.
|
2010-08-06 15:21:30 +08:00
|
|
|
if (V1 == F1 && V2 == F2)
|
|
|
|
return true;
|
|
|
|
if (V1 == F2 && V2 == F1)
|
|
|
|
return true;
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2011-01-28 04:30:54 +08:00
|
|
|
if (const Constant *C1 = dyn_cast<Constant>(V1)) {
|
2011-01-27 16:38:19 +08:00
|
|
|
if (V1 == V2) return true;
|
|
|
|
const Constant *C2 = dyn_cast<Constant>(V2);
|
|
|
|
if (!C2) return false;
|
|
|
|
// TODO: constant expressions with GEP or references to F1 or F2.
|
|
|
|
if (C1->isNullValue() && C2->isNullValue() &&
|
2012-07-19 08:11:40 +08:00
|
|
|
isEquivalentType(C1->getType(), C2->getType()))
|
2011-01-27 16:38:19 +08:00
|
|
|
return true;
|
2011-01-28 03:51:31 +08:00
|
|
|
// Try bitcasting C2 to C1's type. If the bitcast is legal and returns C1
|
|
|
|
// then they must have equal bit patterns.
|
2011-01-27 16:38:19 +08:00
|
|
|
return C1->getType()->canLosslesslyBitCastTo(C2->getType()) &&
|
|
|
|
C1 == ConstantExpr::getBitCast(const_cast<Constant*>(C2), C1->getType());
|
|
|
|
}
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2011-02-06 12:33:50 +08:00
|
|
|
if (isa<InlineAsm>(V1) || isa<InlineAsm>(V2))
|
|
|
|
return V1 == V2;
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2011-02-20 16:11:03 +08:00
|
|
|
// 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.
|
2010-05-13 13:48:45 +08:00
|
|
|
|
2011-02-20 16:11:03 +08:00
|
|
|
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;
|
2010-05-13 13:48:45 +08:00
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Test whether two basic blocks have equivalent behaviour.
|
|
|
|
bool FunctionComparator::compare(const BasicBlock *BB1, const BasicBlock *BB2) {
|
2010-08-02 13:23:03 +08:00
|
|
|
BasicBlock::const_iterator F1I = BB1->begin(), F1E = BB1->end();
|
|
|
|
BasicBlock::const_iterator F2I = BB2->begin(), F2E = BB2->end();
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
do {
|
2011-01-28 16:43:14 +08:00
|
|
|
if (!enumerate(F1I, F2I))
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (const GetElementPtrInst *GEP1 = dyn_cast<GetElementPtrInst>(F1I)) {
|
|
|
|
const GetElementPtrInst *GEP2 = dyn_cast<GetElementPtrInst>(F2I);
|
|
|
|
if (!GEP2)
|
|
|
|
return false;
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
if (!enumerate(GEP1->getPointerOperand(), GEP2->getPointerOperand()))
|
2010-05-13 14:45:13 +08:00
|
|
|
return false;
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
if (!isEquivalentGEP(GEP1, GEP2))
|
2010-05-13 14:45:13 +08:00
|
|
|
return false;
|
2010-05-13 13:48:45 +08:00
|
|
|
} else {
|
2010-08-02 13:23:03 +08:00
|
|
|
if (!isEquivalentOperation(F1I, F2I))
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
assert(F1I->getNumOperands() == F2I->getNumOperands());
|
|
|
|
for (unsigned i = 0, e = F1I->getNumOperands(); i != e; ++i) {
|
|
|
|
Value *OpF1 = F1I->getOperand(i);
|
|
|
|
Value *OpF2 = F2I->getOperand(i);
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
if (!enumerate(OpF1, OpF2))
|
2010-05-13 14:45:13 +08:00
|
|
|
return false;
|
2010-05-13 13:48:45 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (OpF1->getValueID() != OpF2->getValueID() ||
|
|
|
|
!isEquivalentType(OpF1->getType(), OpF2->getType()))
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
++F1I, ++F2I;
|
|
|
|
} while (F1I != F1E && F2I != F2E);
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
return F1I == F1E && F2I == F2E;
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Test whether the two functions have equivalent behaviour.
|
|
|
|
bool FunctionComparator::compare() {
|
2008-11-02 13:52:50 +08:00
|
|
|
// We need to recheck everything, but check the things that weren't included
|
|
|
|
// in the hash first.
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (F1->getAttributes() != F2->getAttributes())
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (F1->hasGC() != F2->hasGC())
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (F1->hasGC() && F1->getGC() != F2->getGC())
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (F1->hasSection() != F2->hasSection())
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (F1->hasSection() && F1->getSection() != F2->getSection())
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (F1->isVarArg() != F2->isVarArg())
|
2009-06-12 16:04:51 +08:00
|
|
|
return false;
|
|
|
|
|
2008-11-02 13:52:50 +08:00
|
|
|
// TODO: if it's internal and only used in direct calls, we could handle this
|
|
|
|
// case too.
|
2010-08-02 13:23:03 +08:00
|
|
|
if (F1->getCallingConv() != F2->getCallingConv())
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
if (!isEquivalentType(F1->getFunctionType(), F2->getFunctionType()))
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
assert(F1->arg_size() == F2->arg_size() &&
|
2010-09-07 09:42:10 +08:00
|
|
|
"Identically typed functions have different numbers of args!");
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
// Visit the arguments so that they get enumerated in the order they're
|
|
|
|
// passed in.
|
2010-08-02 13:23:03 +08:00
|
|
|
for (Function::const_arg_iterator f1i = F1->arg_begin(),
|
|
|
|
f2i = F2->arg_begin(), f1e = F1->arg_end(); f1i != f1e; ++f1i, ++f2i) {
|
2011-01-28 16:43:14 +08:00
|
|
|
if (!enumerate(f1i, f2i))
|
2010-09-07 09:42:10 +08:00
|
|
|
llvm_unreachable("Arguments repeat!");
|
2010-05-13 13:48:45 +08:00
|
|
|
}
|
2008-11-02 13:52:50 +08:00
|
|
|
|
2010-08-08 13:04:23 +08:00
|
|
|
// We do a CFG-ordered walk since the actual ordering of the blocks in the
|
|
|
|
// linked list is immaterial. Our walk starts at the entry block for both
|
2010-08-02 13:23:03 +08:00
|
|
|
// 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.
|
2010-08-06 15:21:30 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
F1BBs.push_back(&F1->getEntryBlock());
|
|
|
|
F2BBs.push_back(&F2->getEntryBlock());
|
2010-08-06 15:21:30 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
VisitedBBs.insert(F1BBs[0]);
|
|
|
|
while (!F1BBs.empty()) {
|
|
|
|
const BasicBlock *F1BB = F1BBs.pop_back_val();
|
|
|
|
const BasicBlock *F2BB = F2BBs.pop_back_val();
|
2010-08-06 15:21:30 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
if (!enumerate(F1BB, F2BB) || !compare(F1BB, F2BB))
|
2008-11-02 13:52:50 +08:00
|
|
|
return false;
|
2010-08-06 15:21:30 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
const TerminatorInst *F1TI = F1BB->getTerminator();
|
|
|
|
const TerminatorInst *F2TI = F2BB->getTerminator();
|
2010-08-06 15:21:30 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
assert(F1TI->getNumSuccessors() == F2TI->getNumSuccessors());
|
|
|
|
for (unsigned i = 0, e = F1TI->getNumSuccessors(); i != e; ++i) {
|
|
|
|
if (!VisitedBBs.insert(F1TI->getSuccessor(i)))
|
2010-05-13 14:45:13 +08:00
|
|
|
continue;
|
2010-08-06 15:21:30 +08:00
|
|
|
|
2010-08-02 13:23:03 +08:00
|
|
|
F1BBs.push_back(F1TI->getSuccessor(i));
|
|
|
|
F2BBs.push_back(F2TI->getSuccessor(i));
|
2010-05-13 13:48:45 +08:00
|
|
|
}
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
return true;
|
|
|
|
}
|
|
|
|
|
2011-01-28 15:36:21 +08:00
|
|
|
namespace {
|
|
|
|
|
|
|
|
/// MergeFunctions finds functions which will generate identical machine code,
|
|
|
|
/// by considering all pointer types to be equivalent. Once identified,
|
|
|
|
/// MergeFunctions will fold them by replacing a call to one to a call to a
|
|
|
|
/// bitcast of the other.
|
|
|
|
///
|
|
|
|
class MergeFunctions : public ModulePass {
|
|
|
|
public:
|
|
|
|
static char ID;
|
|
|
|
MergeFunctions()
|
|
|
|
: ModulePass(ID), HasGlobalAliases(false) {
|
|
|
|
initializeMergeFunctionsPass(*PassRegistry::getPassRegistry());
|
|
|
|
}
|
|
|
|
|
2014-03-05 17:10:37 +08:00
|
|
|
bool runOnModule(Module &M) override;
|
2011-01-28 15:36:21 +08:00
|
|
|
|
|
|
|
private:
|
|
|
|
typedef DenseSet<ComparableFunction> FnSetType;
|
|
|
|
|
|
|
|
/// A work queue of functions that may have been modified and should be
|
|
|
|
/// analyzed again.
|
|
|
|
std::vector<WeakVH> Deferred;
|
|
|
|
|
|
|
|
/// Insert a ComparableFunction into the FnSet, or merge it away if it's
|
|
|
|
/// equal to one that's already present.
|
2011-01-28 16:43:14 +08:00
|
|
|
bool insert(ComparableFunction &NewF);
|
2011-01-28 15:36:21 +08:00
|
|
|
|
|
|
|
/// Remove a Function from the FnSet and queue it up for a second sweep of
|
|
|
|
/// analysis.
|
2011-01-28 16:43:14 +08:00
|
|
|
void remove(Function *F);
|
2011-01-28 15:36:21 +08:00
|
|
|
|
|
|
|
/// Find the functions that use this Value and remove them from FnSet and
|
|
|
|
/// queue the functions.
|
2011-01-28 16:43:14 +08:00
|
|
|
void removeUsers(Value *V);
|
2011-01-28 15:36:21 +08:00
|
|
|
|
|
|
|
/// Replace all direct calls of Old with calls of New. Will bitcast New if
|
|
|
|
/// necessary to make types match.
|
|
|
|
void replaceDirectCallers(Function *Old, Function *New);
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Merge two equivalent functions. Upon completion, G may be deleted, or may
|
|
|
|
/// be converted into a thunk. In either case, it should never be visited
|
|
|
|
/// again.
|
|
|
|
void mergeTwoFunctions(Function *F, Function *G);
|
2011-01-28 15:36:21 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Replace G with a thunk or an alias to F. Deletes G.
|
|
|
|
void writeThunkOrAlias(Function *F, Function *G);
|
2011-01-28 15:36:21 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Replace G with a simple tail call to bitcast(F). Also replace direct uses
|
|
|
|
/// of G with bitcast(F). Deletes G.
|
|
|
|
void writeThunk(Function *F, Function *G);
|
2011-01-28 15:36:21 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// Replace G with an alias to F. Deletes G.
|
|
|
|
void writeAlias(Function *F, Function *G);
|
2011-01-28 15:36:21 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
/// The set of all distinct functions. Use the insert() and remove() methods
|
|
|
|
/// to modify it.
|
2011-01-28 15:36:21 +08:00
|
|
|
FnSetType FnSet;
|
|
|
|
|
2012-10-09 00:38:25 +08:00
|
|
|
/// DataLayout for more accurate GEP comparisons. May be NULL.
|
2014-02-25 22:24:11 +08:00
|
|
|
const DataLayout *DL;
|
2011-01-28 15:36:21 +08:00
|
|
|
|
|
|
|
/// Whether or not the target supports global aliases.
|
|
|
|
bool HasGlobalAliases;
|
|
|
|
};
|
|
|
|
|
|
|
|
} // end anonymous namespace
|
|
|
|
|
|
|
|
char MergeFunctions::ID = 0;
|
|
|
|
INITIALIZE_PASS(MergeFunctions, "mergefunc", "Merge Functions", false, false)
|
|
|
|
|
|
|
|
ModulePass *llvm::createMergeFunctionsPass() {
|
|
|
|
return new MergeFunctions();
|
|
|
|
}
|
|
|
|
|
|
|
|
bool MergeFunctions::runOnModule(Module &M) {
|
|
|
|
bool Changed = false;
|
2014-02-26 01:30:31 +08:00
|
|
|
DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
|
2014-04-25 13:29:35 +08:00
|
|
|
DL = DLP ? &DLP->getDataLayout() : nullptr;
|
2011-01-28 15:36:21 +08:00
|
|
|
|
|
|
|
for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
|
|
|
|
if (!I->isDeclaration() && !I->hasAvailableExternallyLinkage())
|
|
|
|
Deferred.push_back(WeakVH(I));
|
|
|
|
}
|
|
|
|
FnSet.resize(Deferred.size());
|
|
|
|
|
|
|
|
do {
|
|
|
|
std::vector<WeakVH> Worklist;
|
|
|
|
Deferred.swap(Worklist);
|
|
|
|
|
|
|
|
DEBUG(dbgs() << "size of module: " << M.size() << '\n');
|
|
|
|
DEBUG(dbgs() << "size of worklist: " << Worklist.size() << '\n');
|
|
|
|
|
|
|
|
// Insert only strong functions and merge them. Strong function merging
|
|
|
|
// always deletes one of them.
|
|
|
|
for (std::vector<WeakVH>::iterator I = Worklist.begin(),
|
|
|
|
E = Worklist.end(); I != E; ++I) {
|
|
|
|
if (!*I) continue;
|
|
|
|
Function *F = cast<Function>(*I);
|
|
|
|
if (!F->isDeclaration() && !F->hasAvailableExternallyLinkage() &&
|
|
|
|
!F->mayBeOverridden()) {
|
2014-02-21 08:06:31 +08:00
|
|
|
ComparableFunction CF = ComparableFunction(F, DL);
|
2011-01-28 16:43:14 +08:00
|
|
|
Changed |= insert(CF);
|
2011-01-28 15:36:21 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
// Insert only weak functions and merge them. By doing these second we
|
|
|
|
// create thunks to the strong function when possible. When two weak
|
|
|
|
// functions are identical, we create a new strong function with two weak
|
|
|
|
// weak thunks to it which are identical but not mergable.
|
|
|
|
for (std::vector<WeakVH>::iterator I = Worklist.begin(),
|
|
|
|
E = Worklist.end(); I != E; ++I) {
|
|
|
|
if (!*I) continue;
|
|
|
|
Function *F = cast<Function>(*I);
|
|
|
|
if (!F->isDeclaration() && !F->hasAvailableExternallyLinkage() &&
|
|
|
|
F->mayBeOverridden()) {
|
2014-02-21 08:06:31 +08:00
|
|
|
ComparableFunction CF = ComparableFunction(F, DL);
|
2011-01-28 16:43:14 +08:00
|
|
|
Changed |= insert(CF);
|
2011-01-28 15:36:21 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
DEBUG(dbgs() << "size of FnSet: " << FnSet.size() << '\n');
|
|
|
|
} while (!Deferred.empty());
|
|
|
|
|
|
|
|
FnSet.clear();
|
|
|
|
|
|
|
|
return Changed;
|
|
|
|
}
|
|
|
|
|
|
|
|
bool DenseMapInfo<ComparableFunction>::isEqual(const ComparableFunction &LHS,
|
|
|
|
const ComparableFunction &RHS) {
|
|
|
|
if (LHS.getFunc() == RHS.getFunc() &&
|
|
|
|
LHS.getHash() == RHS.getHash())
|
|
|
|
return true;
|
|
|
|
if (!LHS.getFunc() || !RHS.getFunc())
|
|
|
|
return false;
|
2011-02-09 14:32:02 +08:00
|
|
|
|
|
|
|
// One of these is a special "underlying pointer comparison only" object.
|
2014-02-21 08:06:31 +08:00
|
|
|
if (LHS.getDataLayout() == ComparableFunction::LookupOnly ||
|
|
|
|
RHS.getDataLayout() == ComparableFunction::LookupOnly)
|
2011-02-09 14:32:02 +08:00
|
|
|
return false;
|
|
|
|
|
2014-02-21 08:06:31 +08:00
|
|
|
assert(LHS.getDataLayout() == RHS.getDataLayout() &&
|
2011-01-28 15:36:21 +08:00
|
|
|
"Comparing functions for different targets");
|
|
|
|
|
2014-02-21 08:06:31 +08:00
|
|
|
return FunctionComparator(LHS.getDataLayout(), LHS.getFunc(),
|
2011-02-02 13:31:01 +08:00
|
|
|
RHS.getFunc()).compare();
|
2011-01-28 15:36:21 +08:00
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Replace direct callers of Old with New.
|
2011-01-25 16:56:50 +08:00
|
|
|
void MergeFunctions::replaceDirectCallers(Function *Old, Function *New) {
|
|
|
|
Constant *BitcastNew = ConstantExpr::getBitCast(New, Old->getType());
|
2014-03-09 11:16:01 +08:00
|
|
|
for (auto UI = Old->use_begin(), UE = Old->use_end(); UI != UE;) {
|
|
|
|
Use *U = &*UI;
|
2011-01-25 16:56:50 +08:00
|
|
|
++UI;
|
2014-03-09 11:16:01 +08:00
|
|
|
CallSite CS(U->getUser());
|
|
|
|
if (CS && CS.isCallee(U)) {
|
2011-01-28 16:43:14 +08:00
|
|
|
remove(CS.getInstruction()->getParent()->getParent());
|
2014-03-09 11:16:01 +08:00
|
|
|
U->set(BitcastNew);
|
2011-01-25 16:56:50 +08:00
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Replace G with an alias to F if possible, or else a thunk to F. Deletes G.
|
|
|
|
void MergeFunctions::writeThunkOrAlias(Function *F, Function *G) {
|
2011-01-25 16:56:50 +08:00
|
|
|
if (HasGlobalAliases && G->hasUnnamedAddr()) {
|
|
|
|
if (G->hasExternalLinkage() || G->hasLocalLinkage() ||
|
|
|
|
G->hasWeakLinkage()) {
|
2011-01-28 16:43:14 +08:00
|
|
|
writeAlias(F, G);
|
2011-01-25 16:56:50 +08:00
|
|
|
return;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
writeThunk(F, G);
|
2011-01-25 16:56:50 +08:00
|
|
|
}
|
|
|
|
|
2013-09-17 17:36:11 +08:00
|
|
|
// Helper for writeThunk,
|
|
|
|
// Selects proper bitcast operation,
|
2014-01-25 01:20:08 +08:00
|
|
|
// but a bit simpler then CastInst::getCastOpcode.
|
2014-05-01 01:53:04 +08:00
|
|
|
static Value *createCast(IRBuilder<false> &Builder, Value *V, Type *DestTy) {
|
2013-09-17 17:36:11 +08:00
|
|
|
Type *SrcTy = V->getType();
|
2014-05-01 01:53:04 +08:00
|
|
|
if (SrcTy->isStructTy()) {
|
|
|
|
assert(DestTy->isStructTy());
|
|
|
|
assert(SrcTy->getStructNumElements() == DestTy->getStructNumElements());
|
|
|
|
Value *Result = UndefValue::get(DestTy);
|
|
|
|
for (unsigned int I = 0, E = SrcTy->getStructNumElements(); I < E; ++I) {
|
|
|
|
Value *Element = createCast(
|
|
|
|
Builder, Builder.CreateExtractValue(V, ArrayRef<unsigned int>(I)),
|
|
|
|
DestTy->getStructElementType(I));
|
|
|
|
|
|
|
|
Result =
|
|
|
|
Builder.CreateInsertValue(Result, Element, ArrayRef<unsigned int>(I));
|
|
|
|
}
|
|
|
|
return Result;
|
|
|
|
}
|
|
|
|
assert(!DestTy->isStructTy());
|
2013-09-17 17:36:11 +08:00
|
|
|
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);
|
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// 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) {
|
2010-05-13 13:48:45 +08:00
|
|
|
if (!G->mayBeOverridden()) {
|
|
|
|
// Redirect direct callers of G to F.
|
2011-01-25 16:56:50 +08:00
|
|
|
replaceDirectCallers(G, F);
|
2010-05-13 13:48:45 +08:00
|
|
|
}
|
|
|
|
|
2010-09-07 09:42:10 +08:00
|
|
|
// If G was internal then we may have replaced all uses of G with F. If so,
|
2010-08-06 15:21:30 +08:00
|
|
|
// stop here and delete G. There's no need for a thunk.
|
|
|
|
if (G->hasLocalLinkage() && G->use_empty()) {
|
|
|
|
G->eraseFromParent();
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
2009-06-12 23:56:56 +08:00
|
|
|
Function *NewG = Function::Create(G->getFunctionType(), G->getLinkage(), "",
|
|
|
|
G->getParent());
|
2009-08-14 05:58:54 +08:00
|
|
|
BasicBlock *BB = BasicBlock::Create(F->getContext(), "", NewG);
|
2010-08-08 13:04:23 +08:00
|
|
|
IRBuilder<false> Builder(BB);
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2010-05-13 13:48:45 +08:00
|
|
|
SmallVector<Value *, 16> Args;
|
2009-06-12 16:04:51 +08:00
|
|
|
unsigned i = 0;
|
2011-07-18 12:54:35 +08:00
|
|
|
FunctionType *FFTy = F->getFunctionType();
|
2009-06-12 16:04:51 +08:00
|
|
|
for (Function::arg_iterator AI = NewG->arg_begin(), AE = NewG->arg_end();
|
|
|
|
AI != AE; ++AI) {
|
2013-09-17 17:36:11 +08:00
|
|
|
Args.push_back(createCast(Builder, (Value*)AI, FFTy->getParamType(i)));
|
2009-06-12 16:04:51 +08:00
|
|
|
++i;
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2011-07-15 16:37:34 +08:00
|
|
|
CallInst *CI = Builder.CreateCall(F, Args);
|
2009-06-12 16:04:51 +08:00
|
|
|
CI->setTailCall();
|
2009-06-13 00:04:00 +08:00
|
|
|
CI->setCallingConv(F->getCallingConv());
|
2010-01-05 21:12:22 +08:00
|
|
|
if (NewG->getReturnType()->isVoidTy()) {
|
2010-08-08 13:04:23 +08:00
|
|
|
Builder.CreateRetVoid();
|
2009-06-12 16:04:51 +08:00
|
|
|
} else {
|
2013-09-17 17:36:11 +08:00
|
|
|
Builder.CreateRet(createCast(Builder, CI, NewG->getReturnType()));
|
2008-11-03 00:46:26 +08:00
|
|
|
}
|
|
|
|
|
2009-06-12 16:04:51 +08:00
|
|
|
NewG->copyAttributesFrom(G);
|
|
|
|
NewG->takeName(G);
|
2011-01-28 16:43:14 +08:00
|
|
|
removeUsers(G);
|
2009-06-12 16:04:51 +08:00
|
|
|
G->replaceAllUsesWith(NewG);
|
|
|
|
G->eraseFromParent();
|
2010-09-07 09:42:10 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
DEBUG(dbgs() << "writeThunk: " << NewG->getName() << '\n');
|
2010-09-07 09:42:10 +08:00
|
|
|
++NumThunksWritten;
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Replace G with an alias to F and delete G.
|
|
|
|
void MergeFunctions::writeAlias(Function *F, Function *G) {
|
2011-01-25 16:56:50 +08:00
|
|
|
Constant *BitcastF = ConstantExpr::getBitCast(F, G->getType());
|
|
|
|
GlobalAlias *GA = new GlobalAlias(G->getType(), G->getLinkage(), "",
|
|
|
|
BitcastF, G->getParent());
|
|
|
|
F->setAlignment(std::max(F->getAlignment(), G->getAlignment()));
|
|
|
|
GA->takeName(G);
|
|
|
|
GA->setVisibility(G->getVisibility());
|
2011-01-28 16:43:14 +08:00
|
|
|
removeUsers(G);
|
2011-01-25 16:56:50 +08:00
|
|
|
G->replaceAllUsesWith(GA);
|
|
|
|
G->eraseFromParent();
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
DEBUG(dbgs() << "writeAlias: " << GA->getName() << '\n');
|
2011-01-25 16:56:50 +08:00
|
|
|
++NumAliasesWritten;
|
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Merge two equivalent functions. Upon completion, Function G is deleted.
|
|
|
|
void MergeFunctions::mergeTwoFunctions(Function *F, Function *G) {
|
2010-09-07 09:42:10 +08:00
|
|
|
if (F->mayBeOverridden()) {
|
|
|
|
assert(G->mayBeOverridden());
|
2009-06-12 23:56:56 +08:00
|
|
|
|
2011-01-25 16:56:50 +08:00
|
|
|
if (HasGlobalAliases) {
|
|
|
|
// Make them both thunks to the same internal function.
|
|
|
|
Function *H = Function::Create(F->getFunctionType(), F->getLinkage(), "",
|
|
|
|
F->getParent());
|
|
|
|
H->copyAttributesFrom(F);
|
|
|
|
H->takeName(F);
|
2011-01-28 16:43:14 +08:00
|
|
|
removeUsers(F);
|
2011-01-25 16:56:50 +08:00
|
|
|
F->replaceAllUsesWith(H);
|
2009-06-12 23:56:56 +08:00
|
|
|
|
2011-01-25 16:56:50 +08:00
|
|
|
unsigned MaxAlignment = std::max(G->getAlignment(), H->getAlignment());
|
2010-08-10 05:03:28 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
writeAlias(F, G);
|
|
|
|
writeAlias(F, H);
|
2009-06-12 23:56:56 +08:00
|
|
|
|
2011-01-25 16:56:50 +08:00
|
|
|
F->setAlignment(MaxAlignment);
|
|
|
|
F->setLinkage(GlobalValue::PrivateLinkage);
|
|
|
|
} else {
|
|
|
|
// We can't merge them. Instead, pick one and update all direct callers
|
|
|
|
// to call it and hope that we improve the instruction cache hit rate.
|
|
|
|
replaceDirectCallers(G, F);
|
|
|
|
}
|
2010-09-07 09:42:10 +08:00
|
|
|
|
|
|
|
++NumDoubleWeak;
|
2010-08-06 15:21:30 +08:00
|
|
|
} else {
|
2011-01-28 16:43:14 +08:00
|
|
|
writeThunkOrAlias(F, G);
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2009-06-12 16:04:51 +08:00
|
|
|
++NumFunctionsMerged;
|
2008-11-02 13:52:50 +08:00
|
|
|
}
|
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// Insert a ComparableFunction into the FnSet, or merge it away if equal to one
|
|
|
|
// that was already inserted.
|
|
|
|
bool MergeFunctions::insert(ComparableFunction &NewF) {
|
2010-09-05 16:22:49 +08:00
|
|
|
std::pair<FnSetType::iterator, bool> Result = FnSet.insert(NewF);
|
2011-02-09 14:32:02 +08:00
|
|
|
if (Result.second) {
|
|
|
|
DEBUG(dbgs() << "Inserting as unique: " << NewF.getFunc()->getName() << '\n');
|
2010-09-05 16:22:49 +08:00
|
|
|
return false;
|
2011-02-09 14:32:02 +08:00
|
|
|
}
|
2010-08-31 13:53:05 +08:00
|
|
|
|
2010-09-05 17:00:32 +08:00
|
|
|
const ComparableFunction &OldF = *Result.first;
|
2010-09-05 16:22:49 +08:00
|
|
|
|
2013-10-02 02:05:30 +08:00
|
|
|
// 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;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2010-09-05 16:22:49 +08:00
|
|
|
// Never thunk a strong function to a weak function.
|
2010-09-07 09:42:10 +08:00
|
|
|
assert(!OldF.getFunc()->mayBeOverridden() ||
|
|
|
|
NewF.getFunc()->mayBeOverridden());
|
2010-09-05 16:22:49 +08:00
|
|
|
|
2010-09-05 17:00:32 +08:00
|
|
|
DEBUG(dbgs() << " " << OldF.getFunc()->getName() << " == "
|
|
|
|
<< NewF.getFunc()->getName() << '\n');
|
2010-09-05 16:22:49 +08:00
|
|
|
|
2010-09-05 17:00:32 +08:00
|
|
|
Function *DeleteF = NewF.getFunc();
|
|
|
|
NewF.release();
|
2011-01-28 16:43:14 +08:00
|
|
|
mergeTwoFunctions(OldF.getFunc(), DeleteF);
|
2010-09-05 16:22:49 +08:00
|
|
|
return true;
|
2010-08-08 13:04:23 +08:00
|
|
|
}
|
2009-06-12 16:04:51 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// 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) {
|
2011-02-09 14:32:02 +08:00
|
|
|
// 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);
|
2011-01-02 10:46:33 +08:00
|
|
|
if (FnSet.erase(CF)) {
|
2011-02-09 14:32:02 +08:00
|
|
|
DEBUG(dbgs() << "Removed " << F->getName() << " from set and deferred it.\n");
|
2011-01-02 10:46:33 +08:00
|
|
|
Deferred.push_back(F);
|
2010-08-31 13:53:05 +08:00
|
|
|
}
|
2011-01-02 10:46:33 +08:00
|
|
|
}
|
2010-09-05 16:22:49 +08:00
|
|
|
|
2011-01-28 16:43:14 +08:00
|
|
|
// For each instruction used by the value, remove() the function that contains
|
|
|
|
// the instruction. This should happen right before a call to RAUW.
|
|
|
|
void MergeFunctions::removeUsers(Value *V) {
|
2011-01-03 03:16:44 +08:00
|
|
|
std::vector<Value *> Worklist;
|
|
|
|
Worklist.push_back(V);
|
|
|
|
while (!Worklist.empty()) {
|
|
|
|
Value *V = Worklist.back();
|
|
|
|
Worklist.pop_back();
|
|
|
|
|
2014-03-09 11:16:01 +08:00
|
|
|
for (User *U : V->users()) {
|
|
|
|
if (Instruction *I = dyn_cast<Instruction>(U)) {
|
2011-01-28 16:43:14 +08:00
|
|
|
remove(I->getParent()->getParent());
|
2014-03-09 11:16:01 +08:00
|
|
|
} else if (isa<GlobalValue>(U)) {
|
2011-01-15 18:16:23 +08:00
|
|
|
// do nothing
|
2014-03-09 11:16:01 +08:00
|
|
|
} else if (Constant *C = dyn_cast<Constant>(U)) {
|
|
|
|
for (User *UU : C->users())
|
|
|
|
Worklist.push_back(UU);
|
2011-01-03 03:16:44 +08:00
|
|
|
}
|
2010-09-05 16:22:49 +08:00
|
|
|
}
|
2010-08-31 13:53:05 +08:00
|
|
|
}
|
2010-09-05 16:22:49 +08:00
|
|
|
}
|