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Lower stpcpy_chk when possible.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98274 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Christopher 2010-03-11 19:24:34 +00:00
parent 55282267e1
commit 19888ca8b4
4 changed files with 45 additions and 6 deletions
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5
include/llvm/Transforms/Utils/BuildLibCalls.h
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@ -39,6 +39,11 @@ namespace llvm {
Value *EmitStrCpy(Value *Dst, Value *Src, IRBuilder<> &B,
const TargetData *TD);
/// EmitStpCpy - Emit a call to the stpcpy function to the builder, for the
/// specified pointer arguments.
Value *EmitStpCpy(Value *Dst, Value *Src, IRBuilder<> &B,
const TargetData *TD);
/// EmitStrNCpy - Emit a call to the strncpy function to the builder, for the
/// specified pointer arguments and length.
Value *EmitStrNCpy(Value *Dst, Value *Src, Value *Len, IRBuilder<> &B,

13
lib/Transforms/InstCombine/InstCombineCalls.cpp
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@ -838,6 +838,19 @@ Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const TargetData *TD) {
// Should be similar to strcpy.
if (Name == "__stpcpy_chk") {
ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(3));
if (!SizeCI)
return 0;
// If a) we don't have any length information, or b) we know this will
// fit then just lower to a plain stpcpy. Otherwise we'll keep our
// stpcpy_chk call which may fail at runtime if the size is too long.
// TODO: It might be nice to get a maximum length out of the possible
// string lengths for varying.
if (SizeCI->isAllOnesValue() ||
SizeCI->getZExtValue() >= GetStringLength(CI->getOperand(2))) {
Value *Ret = EmitStpCpy(CI->getOperand(1), CI->getOperand(2), B, TD);
return ReplaceInstUsesWith(*CI, Ret);
}
return 0;
}

15
lib/Transforms/Scalar/CodeGenPrepare.cpp
View File

@ -624,11 +624,6 @@ bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(3));
if (!SizeCI)
return 0;
// If a) we don't have any length information, or b) we know this will
// fit then just lower to a plain strcpy. Otherwise we'll keep our
// strcpy_chk call which may fail at runtime if the size is too long.
// TODO: It might be nice to get a maximum length out of the possible
// string lengths for varying.
if (SizeCI->isAllOnesValue()) {
Value *Ret = EmitStrCpy(CI->getOperand(1), CI->getOperand(2), B, TD);
CI->replaceAllUsesWith(Ret);
@ -638,8 +633,16 @@ bool CodeGenPrepare::OptimizeCallInst(CallInst *CI) {
return 0;
}
// Should be similar to strcpy.
if (Name == "__stpcpy_chk") {
ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(3));
if (!SizeCI)
return 0;
if (SizeCI->isAllOnesValue()) {
Value *Ret = EmitStpCpy(CI->getOperand(1), CI->getOperand(2), B, TD);
CI->replaceAllUsesWith(Ret);
CI->eraseFromParent();
return true;
}
return 0;
}

18
lib/Transforms/Utils/BuildLibCalls.cpp
View File

@ -87,6 +87,24 @@ Value *llvm::EmitStrCpy(Value *Dst, Value *Src, IRBuilder<> &B,
return CI;
}
/// EmitStpCpy - Emit a call to the stpcpy function to the builder, for the
/// specified pointer arguments.
Value *llvm::EmitStpCpy(Value *Dst, Value *Src, IRBuilder<> &B,
const TargetData *TD) {
Module *M = B.GetInsertBlock()->getParent()->getParent();
AttributeWithIndex AWI[2];
AWI[0] = AttributeWithIndex::get(2, Attribute::NoCapture);
AWI[1] = AttributeWithIndex::get(~0u, Attribute::NoUnwind);
const Type *I8Ptr = B.getInt8PtrTy();
Value *StpCpy = M->getOrInsertFunction("stpcpy", AttrListPtr::get(AWI, 2),
I8Ptr, I8Ptr, I8Ptr, NULL);
CallInst *CI = B.CreateCall2(StpCpy, CastToCStr(Dst, B), CastToCStr(Src, B),
"stpcpy");
if (const Function *F = dyn_cast<Function>(StpCpy->stripPointerCasts()))
CI->setCallingConv(F->getCallingConv());
return CI;
}
/// EmitStrNCpy - Emit a call to the strncpy function to the builder, for the
/// specified pointer arguments.
Value *llvm::EmitStrNCpy(Value *Dst, Value *Src, Value *Len,