[llvm] r225640 - [SimplifyLibCalls] Factor out fortified libcall handling.
Ahmed Bougacha
ahmed.bougacha at gmail.com
Mon Jan 12 09:22:43 PST 2015
Author: ab
Date: Mon Jan 12 11:22:43 2015
New Revision: 225640
URL: http://llvm.org/viewvc/llvm-project?rev=225640&view=rev
Log:
[SimplifyLibCalls] Factor out fortified libcall handling.
This lets us remove CGP duplicate.
Differential Revision: http://reviews.llvm.org/D6541
Modified:
llvm/trunk/include/llvm/Transforms/Utils/BuildLibCalls.h
llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h
llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp
llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
Modified: llvm/trunk/include/llvm/Transforms/Utils/BuildLibCalls.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/BuildLibCalls.h?rev=225640&r1=225639&r2=225640&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/BuildLibCalls.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/BuildLibCalls.h Mon Jan 12 11:22:43 2015
@@ -115,20 +115,6 @@ namespace llvm {
/// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
Value *EmitFWrite(Value *Ptr, Value *Size, Value *File, IRBuilder<> &B,
const DataLayout *TD, const TargetLibraryInfo *TLI);
-
- /// SimplifyFortifiedLibCalls - Helper class for folding checked library
- /// calls (e.g. __strcpy_chk) into their unchecked counterparts.
- class SimplifyFortifiedLibCalls {
- protected:
- CallInst *CI;
- virtual void replaceCall(Value *With) = 0;
- virtual bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp,
- bool isString) const = 0;
-
- public:
- virtual ~SimplifyFortifiedLibCalls();
- bool fold(CallInst *CI, const DataLayout *TD, const TargetLibraryInfo *TLI);
- };
}
#endif
Modified: llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h?rev=225640&r1=225639&r2=225640&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h (original)
+++ llvm/trunk/include/llvm/Transforms/Utils/SimplifyLibCalls.h Mon Jan 12 11:22:43 2015
@@ -27,11 +27,46 @@ class TargetLibraryInfo;
class BasicBlock;
class Function;
+/// \brief This class implements simplifications for calls to fortified library
+/// functions (__st*cpy_chk, __memcpy_chk, __memmove_chk, __memset_chk), to,
+/// when possible, replace them with their non-checking counterparts.
+/// Other optimizations can also be done, but it's possible to disable them and
+/// only simplify needless use of the checking versions (when the object size
+/// is unknown) by passing true for OnlyLowerUnknownSize.
+class FortifiedLibCallSimplifier {
+private:
+ const DataLayout *DL;
+ const TargetLibraryInfo *TLI;
+ bool OnlyLowerUnknownSize;
+
+public:
+ FortifiedLibCallSimplifier(const DataLayout *DL, const TargetLibraryInfo *TLI,
+ bool OnlyLowerUnknownSize = false);
+
+ /// \brief Take the given call instruction and return a more
+ /// optimal value to replace the instruction with or 0 if a more
+ /// optimal form can't be found.
+ Value *optimizeCall(CallInst *CI);
+
+private:
+ Value *optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B);
+ Value *optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B);
+ Value *optimizeMemSetChk(CallInst *CI, IRBuilder<> &B);
+ Value *optimizeStrCpyChk(CallInst *CI, IRBuilder<> &B);
+ Value *optimizeStrNCpyChk(CallInst *CI, IRBuilder<> &B);
+
+ /// \brief Checks whether the call \p CI to a fortified libcall is foldable
+ /// to the non-fortified version.
+ bool isFortifiedCallFoldable(CallInst *CI, unsigned ObjSizeOp,
+ unsigned SizeOp, bool isString);
+};
+
/// LibCallSimplifier - This class implements a collection of optimizations
/// that replace well formed calls to library functions with a more optimal
/// form. For example, replacing 'printf("Hello!")' with 'puts("Hello!")'.
class LibCallSimplifier {
private:
+ FortifiedLibCallSimplifier FortifiedSimplifier;
const DataLayout *DL;
const TargetLibraryInfo *TLI;
bool UnsafeFPShrink;
@@ -56,14 +91,6 @@ public:
virtual void replaceAllUsesWith(Instruction *I, Value *With) const;
private:
- // Fortified Library Call Optimizations
- Value *optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B);
- Value *optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B);
- Value *optimizeMemSetChk(CallInst *CI, IRBuilder<> &B);
- Value *optimizeStrCpyChk(CallInst *CI, IRBuilder<> &B);
- Value *optimizeStpCpyChk(CallInst *CI, IRBuilder<> &B);
- Value *optimizeStrNCpyChk(CallInst *CI, IRBuilder<> &B);
-
// String and Memory Library Call Optimizations
Value *optimizeStrCat(CallInst *CI, IRBuilder<> &B);
Value *optimizeStrNCat(CallInst *CI, IRBuilder<> &B);
Modified: llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp?rev=225640&r1=225639&r2=225640&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp (original)
+++ llvm/trunk/lib/CodeGen/CodeGenPrepare.cpp Mon Jan 12 11:22:43 2015
@@ -45,6 +45,7 @@
#include "llvm/Transforms/Utils/BuildLibCalls.h"
#include "llvm/Transforms/Utils/BypassSlowDivision.h"
#include "llvm/Transforms/Utils/Local.h"
+#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
using namespace llvm;
using namespace llvm::PatternMatch;
@@ -847,22 +848,6 @@ static bool OptimizeExtractBits(BinaryOp
return MadeChange;
}
-namespace {
-class CodeGenPrepareFortifiedLibCalls : public SimplifyFortifiedLibCalls {
-protected:
- void replaceCall(Value *With) override {
- CI->replaceAllUsesWith(With);
- CI->eraseFromParent();
- }
- bool isFoldable(unsigned SizeCIOp, unsigned, bool) const override {
- if (ConstantInt *SizeCI =
- dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp)))
- return SizeCI->isAllOnesValue();
- return false;
- }
-};
-} // end anonymous namespace
-
// ScalarizeMaskedLoad() translates masked load intrinsic, like
// <16 x i32 > @llvm.masked.load( <16 x i32>* %addr, i32 align,
// <16 x i1> %mask, <16 x i32> %passthru)
@@ -1152,10 +1137,15 @@ bool CodeGenPrepare::OptimizeCallInst(Ca
// Lower all default uses of _chk calls. This is very similar
// to what InstCombineCalls does, but here we are only lowering calls
- // that have the default "don't know" as the objectsize. Anything else
- // should be left alone.
- CodeGenPrepareFortifiedLibCalls Simplifier;
- return Simplifier.fold(CI, TD, TLInfo);
+ // to fortified library functions (e.g. __memcpy_chk) that have the default
+ // "don't know" as the objectsize. Anything else should be left alone.
+ FortifiedLibCallSimplifier Simplifier(TD, TLInfo, true);
+ if (Value *V = Simplifier.optimizeCall(CI)) {
+ CI->replaceAllUsesWith(V);
+ CI->eraseFromParent();
+ return true;
+ }
+ return false;
}
/// DupRetToEnableTailCallOpts - Look for opportunities to duplicate return
Modified: llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp?rev=225640&r1=225639&r2=225640&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/BuildLibCalls.cpp Mon Jan 12 11:22:43 2015
@@ -486,135 +486,3 @@ Value *llvm::EmitFWrite(Value *Ptr, Valu
CI->setCallingConv(Fn->getCallingConv());
return CI;
}
-
-SimplifyFortifiedLibCalls::~SimplifyFortifiedLibCalls() { }
-
-bool SimplifyFortifiedLibCalls::fold(CallInst *CI, const DataLayout *TD,
- const TargetLibraryInfo *TLI) {
- // We really need DataLayout for later.
- if (!TD) return false;
-
- this->CI = CI;
- Function *Callee = CI->getCalledFunction();
- StringRef Name = Callee->getName();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getParent()->getContext();
- IRBuilder<> B(CI);
-
- if (Name == "__memcpy_chk") {
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isPointerTy() ||
- FT->getParamType(2) != TD->getIntPtrType(Context) ||
- FT->getParamType(3) != TD->getIntPtrType(Context))
- return false;
-
- if (isFoldable(3, 2, false)) {
- B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), 1);
- replaceCall(CI->getArgOperand(0));
- return true;
- }
- return false;
- }
-
- // Should be similar to memcpy.
- if (Name == "__mempcpy_chk") {
- return false;
- }
-
- if (Name == "__memmove_chk") {
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isPointerTy() ||
- FT->getParamType(2) != TD->getIntPtrType(Context) ||
- FT->getParamType(3) != TD->getIntPtrType(Context))
- return false;
-
- if (isFoldable(3, 2, false)) {
- B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), 1);
- replaceCall(CI->getArgOperand(0));
- return true;
- }
- return false;
- }
-
- if (Name == "__memset_chk") {
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isIntegerTy() ||
- FT->getParamType(2) != TD->getIntPtrType(Context) ||
- FT->getParamType(3) != TD->getIntPtrType(Context))
- return false;
-
- if (isFoldable(3, 2, false)) {
- Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(),
- false);
- B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
- replaceCall(CI->getArgOperand(0));
- return true;
- }
- return false;
- }
-
- if (Name == "__strcpy_chk" || Name == "__stpcpy_chk") {
- // Check if this has the right signature.
- if (FT->getNumParams() != 3 ||
- FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- FT->getParamType(2) != TD->getIntPtrType(Context))
- 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 (isFoldable(2, 1, true)) {
- Value *Ret = EmitStrCpy(CI->getArgOperand(0), CI->getArgOperand(1), B, TD,
- TLI, Name.substr(2, 6));
- if (!Ret)
- return false;
- replaceCall(Ret);
- return true;
- }
- return false;
- }
-
- if (Name == "__strncpy_chk" || Name == "__stpncpy_chk") {
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- !FT->getParamType(2)->isIntegerTy() ||
- FT->getParamType(3) != TD->getIntPtrType(Context))
- return false;
-
- if (isFoldable(3, 2, false)) {
- Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), B, TD, TLI,
- Name.substr(2, 7));
- if (!Ret)
- return false;
- replaceCall(Ret);
- return true;
- }
- return false;
- }
-
- if (Name == "__strcat_chk") {
- return false;
- }
-
- if (Name == "__strncat_chk") {
- return false;
- }
-
- return false;
-}
Modified: llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp?rev=225640&r1=225639&r2=225640&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SimplifyLibCalls.cpp Mon Jan 12 11:22:43 2015
@@ -181,209 +181,6 @@ static bool checkStringCopyLibFuncSignat
}
//===----------------------------------------------------------------------===//
-// Fortified Library Call Optimizations
-//===----------------------------------------------------------------------===//
-
-static bool isFortifiedCallFoldable(CallInst *CI, unsigned SizeCIOp, unsigned SizeArgOp,
- bool isString) {
- if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp))
- return true;
- if (ConstantInt *SizeCI =
- dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) {
- if (SizeCI->isAllOnesValue())
- return true;
- if (isString) {
- uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp));
- // If the length is 0 we don't know how long it is and so we can't
- // remove the check.
- if (Len == 0)
- return false;
- return SizeCI->getZExtValue() >= Len;
- }
- if (ConstantInt *Arg = dyn_cast<ConstantInt>(CI->getArgOperand(SizeArgOp)))
- return SizeCI->getZExtValue() >= Arg->getZExtValue();
- }
- return false;
-}
-
-Value *LibCallSimplifier::optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isPointerTy() ||
- FT->getParamType(2) != DL->getIntPtrType(Context) ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), 1);
- return CI->getArgOperand(0);
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isPointerTy() ||
- FT->getParamType(2) != DL->getIntPtrType(Context) ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), 1);
- return CI->getArgOperand(0);
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeMemSetChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- !FT->getParamType(0)->isPointerTy() ||
- !FT->getParamType(1)->isIntegerTy() ||
- FT->getParamType(2) != DL->getIntPtrType(Context) ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
- B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
- return CI->getArgOperand(0);
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeStrCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- StringRef Name = Callee->getName();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- FT->getParamType(2) != DL->getIntPtrType(Context))
- return nullptr;
-
- Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
- if (Dst == Src) // __strcpy_chk(x,x) -> x
- return Src;
-
- // 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 (isFortifiedCallFoldable(CI, 2, 1, true)) {
- Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
- return Ret;
- } else {
- // Maybe we can stil fold __strcpy_chk to __memcpy_chk.
- uint64_t Len = GetStringLength(Src);
- if (Len == 0)
- return nullptr;
-
- // This optimization require DataLayout.
- if (!DL)
- return nullptr;
-
- Value *Ret = EmitMemCpyChk(
- Dst, Src, ConstantInt::get(DL->getIntPtrType(Context), Len),
- CI->getArgOperand(2), B, DL, TLI);
- return Ret;
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeStpCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- StringRef Name = Callee->getName();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- FT->getParamType(2) != DL->getIntPtrType(FT->getParamType(0)))
- return nullptr;
-
- Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
- if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
- Value *StrLen = EmitStrLen(Src, B, DL, TLI);
- return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
- }
-
- // 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 (isFortifiedCallFoldable(CI, 2, 1, true)) {
- Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
- return Ret;
- } else {
- // Maybe we can stil fold __stpcpy_chk to __memcpy_chk.
- uint64_t Len = GetStringLength(Src);
- if (Len == 0)
- return nullptr;
-
- // This optimization require DataLayout.
- if (!DL)
- return nullptr;
-
- Type *PT = FT->getParamType(0);
- Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
- Value *DstEnd =
- B.CreateGEP(Dst, ConstantInt::get(DL->getIntPtrType(PT), Len - 1));
- if (!EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B, DL, TLI))
- return nullptr;
- return DstEnd;
- }
- return nullptr;
-}
-
-Value *LibCallSimplifier::optimizeStrNCpyChk(CallInst *CI, IRBuilder<> &B) {
- Function *Callee = CI->getCalledFunction();
- StringRef Name = Callee->getName();
- FunctionType *FT = Callee->getFunctionType();
- LLVMContext &Context = CI->getContext();
-
- // Check if this has the right signature.
- if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
- FT->getParamType(0) != FT->getParamType(1) ||
- FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
- !FT->getParamType(2)->isIntegerTy() ||
- FT->getParamType(3) != DL->getIntPtrType(Context))
- return nullptr;
-
- if (isFortifiedCallFoldable(CI, 3, 2, false)) {
- Value *Ret =
- EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
- CI->getArgOperand(2), B, DL, TLI, Name.substr(2, 7));
- return Ret;
- }
- return nullptr;
-}
-
-//===----------------------------------------------------------------------===//
// String and Memory Library Call Optimizations
//===----------------------------------------------------------------------===//
@@ -2166,6 +1963,15 @@ Value *LibCallSimplifier::optimizeCall(C
}
}
+ // Also try to simplify calls to fortified library functions.
+ if (Value *SimplifiedFortifiedCI = FortifiedSimplifier.optimizeCall(CI)) {
+ // Try to further simplify the result.
+ if (CallInst *SimplifiedCI = dyn_cast<CallInst>(SimplifiedFortifiedCI))
+ if (Value *V = optimizeStringMemoryLibCall(SimplifiedCI, Builder))
+ return V;
+ return SimplifiedFortifiedCI;
+ }
+
// Then check for known library functions.
if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
// We never change the calling convention.
@@ -2270,29 +2076,16 @@ Value *LibCallSimplifier::optimizeCall(C
if (hasFloatVersion(FuncName))
return optimizeBinaryDoubleFP(CI, Builder);
return nullptr;
- case LibFunc::memcpy_chk:
- return optimizeMemCpyChk(CI, Builder);
- case LibFunc::memmove_chk:
- return optimizeMemMoveChk(CI, Builder);
- case LibFunc::memset_chk:
- return optimizeMemSetChk(CI, Builder);
- case LibFunc::strcpy_chk:
- return optimizeStrCpyChk(CI, Builder);
- case LibFunc::stpcpy_chk:
- return optimizeStpCpyChk(CI, Builder);
- case LibFunc::stpncpy_chk:
- case LibFunc::strncpy_chk:
- return optimizeStrNCpyChk(CI, Builder);
default:
return nullptr;
}
}
-
return nullptr;
}
LibCallSimplifier::LibCallSimplifier(const DataLayout *DL,
const TargetLibraryInfo *TLI) :
+ FortifiedSimplifier(DL, TLI),
DL(DL),
TLI(TLI),
UnsafeFPShrink(false) {
@@ -2350,3 +2143,184 @@ void LibCallSimplifier::replaceAllUsesWi
// * trunc(cnst) -> cnst'
//
//
+
+//===----------------------------------------------------------------------===//
+// Fortified Library Call Optimizations
+//===----------------------------------------------------------------------===//
+
+bool FortifiedLibCallSimplifier::isFortifiedCallFoldable(CallInst *CI,
+ unsigned ObjSizeOp,
+ unsigned SizeOp,
+ bool isString) {
+ if (CI->getArgOperand(ObjSizeOp) == CI->getArgOperand(SizeOp))
+ return true;
+ if (ConstantInt *ObjSizeCI =
+ dyn_cast<ConstantInt>(CI->getArgOperand(ObjSizeOp))) {
+ if (ObjSizeCI->isAllOnesValue())
+ return true;
+ // If the object size wasn't -1 (unknown), bail out if we were asked to.
+ if (OnlyLowerUnknownSize)
+ return false;
+ if (isString) {
+ uint64_t Len = GetStringLength(CI->getArgOperand(SizeOp));
+ // If the length is 0 we don't know how long it is and so we can't
+ // remove the check.
+ if (Len == 0)
+ return false;
+ return ObjSizeCI->getZExtValue() >= Len;
+ }
+ if (ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getArgOperand(SizeOp)))
+ return ObjSizeCI->getZExtValue() >= SizeCI->getZExtValue();
+ }
+ return false;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy_chk, DL))
+ return nullptr;
+
+ if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+ B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+ CI->getArgOperand(2), 1);
+ return CI->getArgOperand(0);
+ }
+ return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove_chk, DL))
+ return nullptr;
+
+ if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+ B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
+ CI->getArgOperand(2), 1);
+ return CI->getArgOperand(0);
+ }
+ return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeMemSetChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+
+ if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset_chk, DL))
+ return nullptr;
+
+ if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+ Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
+ B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
+ return CI->getArgOperand(0);
+ }
+ return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrCpyChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+ StringRef Name = Callee->getName();
+ LibFunc::Func Func =
+ Name.startswith("str") ? LibFunc::strcpy_chk : LibFunc::stpcpy_chk;
+
+ if (!checkStringCopyLibFuncSignature(Callee, Func, DL))
+ return nullptr;
+
+ Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1),
+ *ObjSize = CI->getArgOperand(2);
+
+ // __stpcpy_chk(x,x,...) -> x+strlen(x)
+ if (!OnlyLowerUnknownSize && Dst == Src) {
+ Value *StrLen = EmitStrLen(Src, B, DL, TLI);
+ return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
+ }
+
+ // 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 (isFortifiedCallFoldable(CI, 2, 1, true)) {
+ Value *Ret = EmitStrCpy(Dst, Src, B, DL, TLI, Name.substr(2, 6));
+ return Ret;
+ } else if (!OnlyLowerUnknownSize) {
+ // Maybe we can stil fold __st[rp]cpy_chk to __memcpy_chk.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0)
+ return nullptr;
+
+ // This optimization requires DataLayout.
+ if (!DL)
+ return nullptr;
+
+ Type *SizeTTy = DL->getIntPtrType(CI->getContext());
+ Value *LenV = ConstantInt::get(SizeTTy, Len);
+ Value *Ret = EmitMemCpyChk(Dst, Src, LenV, ObjSize, B, DL, TLI);
+ // If the function was an __stpcpy_chk, and we were able to fold it into
+ // a __memcpy_chk, we still need to return the correct end pointer.
+ if (Ret && Func == LibFunc::stpcpy_chk)
+ return B.CreateGEP(Dst, ConstantInt::get(SizeTTy, Len - 1));
+ return Ret;
+ }
+ return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeStrNCpyChk(CallInst *CI, IRBuilder<> &B) {
+ Function *Callee = CI->getCalledFunction();
+ StringRef Name = Callee->getName();
+ LibFunc::Func Func =
+ Name.startswith("str") ? LibFunc::strncpy_chk : LibFunc::stpncpy_chk;
+
+ if (!checkStringCopyLibFuncSignature(Callee, Func, DL))
+ return nullptr;
+ if (isFortifiedCallFoldable(CI, 3, 2, false)) {
+ Value *Ret =
+ EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
+ CI->getArgOperand(2), B, DL, TLI, Name.substr(2, 7));
+ return Ret;
+ }
+ return nullptr;
+}
+
+Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
+ if (CI->isNoBuiltin())
+ return nullptr;
+
+ LibFunc::Func Func;
+ Function *Callee = CI->getCalledFunction();
+ StringRef FuncName = Callee->getName();
+ IRBuilder<> Builder(CI);
+ bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
+
+ // First, check that this is a known library functions.
+ if (!TLI->getLibFunc(FuncName, Func) || !TLI->has(Func))
+ return nullptr;
+
+ // We never change the calling convention.
+ if (!ignoreCallingConv(Func) && !isCallingConvC)
+ return nullptr;
+
+ switch (Func) {
+ case LibFunc::memcpy_chk:
+ return optimizeMemCpyChk(CI, Builder);
+ case LibFunc::memmove_chk:
+ return optimizeMemMoveChk(CI, Builder);
+ case LibFunc::memset_chk:
+ return optimizeMemSetChk(CI, Builder);
+ case LibFunc::stpcpy_chk:
+ case LibFunc::strcpy_chk:
+ return optimizeStrCpyChk(CI, Builder);
+ case LibFunc::stpncpy_chk:
+ case LibFunc::strncpy_chk:
+ return optimizeStrNCpyChk(CI, Builder);
+ default:
+ break;
+ }
+ return nullptr;
+}
+
+FortifiedLibCallSimplifier::
+FortifiedLibCallSimplifier(const DataLayout *DL, const TargetLibraryInfo *TLI,
+ bool OnlyLowerUnknownSize)
+ : DL(DL), TLI(TLI), OnlyLowerUnknownSize(OnlyLowerUnknownSize) {
+}
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