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author | Benjamin Kramer <benny.kra@googlemail.com> | 2010-03-12 09:27:41 +0000 |
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committer | Benjamin Kramer <benny.kra@googlemail.com> | 2010-03-12 09:27:41 +0000 |
commit | 0b6cb507385c8bd10b6a51b5e45a9b99d8d94798 (patch) | |
tree | 5b215ee4ea7339e068a16c0b92203d6c41f944c8 /lib/Transforms/InstCombine | |
parent | b3e87b2262087cf69f7461e4bc586cdb747434f7 (diff) | |
download | external_llvm-0b6cb507385c8bd10b6a51b5e45a9b99d8d94798.zip external_llvm-0b6cb507385c8bd10b6a51b5e45a9b99d8d94798.tar.gz external_llvm-0b6cb507385c8bd10b6a51b5e45a9b99d8d94798.tar.bz2 |
Factor checked library call optimization into a common helper class and use it
to unify the almost identical code in CodeGenPrepare and InstCombineCalls.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98338 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms/InstCombine')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineCalls.cpp | 132 |
1 files changed, 28 insertions, 104 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp index 4b933f0..bdb46eb 100644 --- a/lib/Transforms/InstCombine/InstCombineCalls.cpp +++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp @@ -751,117 +751,41 @@ static bool isSafeToEliminateVarargsCast(const CallSite CS, return true; } +namespace { +class InstCombineFortifiedLibCalls : public SimplifyFortifiedLibCalls { + InstCombiner *IC; +protected: + void replaceCall(Value *With) { + NewInstruction = IC->ReplaceInstUsesWith(*CI, With); + } + bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const { + if (ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(SizeCIOp))) { + if (SizeCI->isAllOnesValue()) + return true; + if (isString) + return SizeCI->getZExtValue() >= + GetStringLength(CI->getOperand(SizeArgOp)); + if (ConstantInt *Arg = dyn_cast<ConstantInt>(CI->getOperand(SizeArgOp))) + return SizeCI->getZExtValue() <= Arg->getZExtValue(); + } + return false; + } +public: + InstCombineFortifiedLibCalls(InstCombiner *IC) : IC(IC), NewInstruction(0) { } + Instruction *NewInstruction; +}; +} // end anonymous namespace + // Try to fold some different type of calls here. // Currently we're only working with the checking functions, memcpy_chk, // mempcpy_chk, memmove_chk, memset_chk, strcpy_chk, stpcpy_chk, strncpy_chk, // strcat_chk and strncat_chk. Instruction *InstCombiner::tryOptimizeCall(CallInst *CI, const TargetData *TD) { if (CI->getCalledFunction() == 0) return 0; - - StringRef Name = CI->getCalledFunction()->getName(); - BasicBlock *BB = CI->getParent(); - IRBuilder<> B(CI->getParent()->getContext()); - - // Set the builder to the instruction after the call. - B.SetInsertPoint(BB, CI); - if (Name == "__memcpy_chk") { - ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(4)); - if (!SizeCI) - return 0; - ConstantInt *SizeArg = dyn_cast<ConstantInt>(CI->getOperand(3)); - if (!SizeArg) - return 0; - if (SizeCI->isAllOnesValue() || - SizeCI->getZExtValue() <= SizeArg->getZExtValue()) { - EmitMemCpy(CI->getOperand(1), CI->getOperand(2), CI->getOperand(3), - 1, B, TD); - return ReplaceInstUsesWith(*CI, CI->getOperand(1)); - } - return 0; - } - - // Should be similar to memcpy. - if (Name == "__mempcpy_chk") { - return 0; - } - - if (Name == "__memmove_chk") { - ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(4)); - if (!SizeCI) - return 0; - ConstantInt *SizeArg = dyn_cast<ConstantInt>(CI->getOperand(3)); - if (!SizeArg) - return 0; - if (SizeCI->isAllOnesValue() || - SizeCI->getZExtValue() <= SizeArg->getZExtValue()) { - EmitMemMove(CI->getOperand(1), CI->getOperand(2), CI->getOperand(3), - 1, B, TD); - return ReplaceInstUsesWith(*CI, CI->getOperand(1)); - } - return 0; - } - - if (Name == "__memset_chk") { - ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(4)); - if (!SizeCI) - return 0; - ConstantInt *SizeArg = dyn_cast<ConstantInt>(CI->getOperand(3)); - if (!SizeArg) - return 0; - if (SizeCI->isAllOnesValue() || - SizeCI->getZExtValue() <= SizeArg->getZExtValue()) { - Value *Val = B.CreateIntCast(CI->getOperand(2), B.getInt8Ty(), - false); - EmitMemSet(CI->getOperand(1), Val, CI->getOperand(3), B, TD); - return ReplaceInstUsesWith(*CI, CI->getOperand(1)); - } - return 0; - } - - if (Name == "__strcpy_chk" || 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 st[rp]cpy. Otherwise we'll keep our - // st[rp]cpy_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 = EmitStrCpy(CI->getOperand(1), CI->getOperand(2), B, TD, - Name.substr(2, 6)); - return ReplaceInstUsesWith(*CI, Ret); - } - return 0; - } - - if (Name == "__strncpy_chk") { - ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getOperand(4)); - if (!SizeCI) - return 0; - ConstantInt *SizeArg = dyn_cast<ConstantInt>(CI->getOperand(3)); - if (!SizeArg) - return 0; - if (SizeCI->isAllOnesValue() || - SizeCI->getZExtValue() <= SizeArg->getZExtValue()) { - Value *Ret = EmitStrNCpy(CI->getOperand(1), CI->getOperand(2), - CI->getOperand(3), B, TD); - return ReplaceInstUsesWith(*CI, Ret); - } - return 0; - } - - if (Name == "__strcat_chk") { - return 0; - } - - if (Name == "__strncat_chk") { - return 0; - } - - return 0; + InstCombineFortifiedLibCalls Simplifier(this); + Simplifier.fold(CI, TD); + return Simplifier.NewInstruction; } // visitCallSite - Improvements for call and invoke instructions. |