From fa9d1372c99e5b74406a606756ba77d620d575bb Mon Sep 17 00:00:00 2001 From: Meador Inge Date: Wed, 31 Oct 2012 00:20:51 +0000 Subject: [PATCH] instcombine: Split out the __stpcpy_chk simplifications from StrCpyChkOpt r166198 migrated the strcpy optimization to instcombine. The strcpy simplifier that was migrated from Transforms/Scalar/SimplifyLibCalls.cpp was also doing some __strcpy_chk simplifications. Those fortified simplifications were migrated as well, but introduced a bug in the __stpcpy_chk simplifier in the process. This happened because the __strcpy_chk and __stpcpy_chk simplifiers were both mapped to StrCpyChkOpt which was updated with simplifications that worked for __strcpy_chk, but not __stpcpy_chk. This patch fixes the problem by adding proper test coverage and creating a new simplifier for __stpcpy_chk (instead of sharing one with __strcpy_chk). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167082 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/SimplifyLibCalls.cpp | 57 +++++++++++- test/Transforms/InstCombine/stpcpy_chk-1.ll | 96 +++++++++++++++++++++ test/Transforms/InstCombine/stpcpy_chk-2.ll | 21 +++++ 3 files changed, 171 insertions(+), 3 deletions(-) create mode 100644 test/Transforms/InstCombine/stpcpy_chk-1.ll create mode 100644 test/Transforms/InstCombine/stpcpy_chk-2.ll diff --git a/lib/Transforms/Utils/SimplifyLibCalls.cpp b/lib/Transforms/Utils/SimplifyLibCalls.cpp index 162b29e8291..5984a96cd0f 100644 --- a/lib/Transforms/Utils/SimplifyLibCalls.cpp +++ b/lib/Transforms/Utils/SimplifyLibCalls.cpp @@ -185,8 +185,8 @@ struct StrCpyChkOpt : public InstFortifiedLibCallOptimization { return Src; // 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. + // 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 (isFoldable(2, 1, true)) { @@ -210,6 +210,56 @@ struct StrCpyChkOpt : public InstFortifiedLibCallOptimization { } }; +struct StpCpyChkOpt : public InstFortifiedLibCallOptimization { + virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { + this->CI = CI; + StringRef Name = Callee->getName(); + FunctionType *FT = Callee->getFunctionType(); + LLVMContext &Context = CI->getParent()->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) != TD->getIntPtrType(FT->getParamType(0))) + return 0; + + Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1); + if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x) + Value *StrLen = EmitStrLen(Src, B, TD, TLI); + return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : 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 (isFoldable(2, 1, true)) { + Value *Ret = EmitStrCpy(Dst, Src, B, TD, 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 0; + + // This optimization require DataLayout. + if (!TD) return 0; + + Type *PT = FT->getParamType(0); + Value *LenV = ConstantInt::get(TD->getIntPtrType(PT), Len); + Value *DstEnd = B.CreateGEP(Dst, + ConstantInt::get(TD->getIntPtrType(PT), + Len - 1)); + if (!EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B, TD, TLI)) + return 0; + return DstEnd; + } + return 0; + } +}; + struct StrNCpyChkOpt : public InstFortifiedLibCallOptimization { virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) { this->CI = CI; @@ -556,6 +606,7 @@ class LibCallSimplifierImpl { MemMoveChkOpt MemMoveChk; MemSetChkOpt MemSetChk; StrCpyChkOpt StrCpyChk; + StpCpyChkOpt StpCpyChk; StrNCpyChkOpt StrNCpyChk; // String and memory library call optimizations. @@ -583,7 +634,7 @@ void LibCallSimplifierImpl::initOptimizations() { Optimizations["__memmove_chk"] = &MemMoveChk; Optimizations["__memset_chk"] = &MemSetChk; Optimizations["__strcpy_chk"] = &StrCpyChk; - Optimizations["__stpcpy_chk"] = &StrCpyChk; + Optimizations["__stpcpy_chk"] = &StpCpyChk; Optimizations["__strncpy_chk"] = &StrNCpyChk; Optimizations["__stpncpy_chk"] = &StrNCpyChk; diff --git a/test/Transforms/InstCombine/stpcpy_chk-1.ll b/test/Transforms/InstCombine/stpcpy_chk-1.ll new file mode 100644 index 00000000000..d06b3286f51 --- /dev/null +++ b/test/Transforms/InstCombine/stpcpy_chk-1.ll @@ -0,0 +1,96 @@ +; Test lib call simplification of __stpcpy_chk calls with various values +; for src, dst, and slen. +; +; RUN: opt < %s -instcombine -S | FileCheck %s + +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" + +@a = common global [60 x i8] zeroinitializer, align 1 +@b = common global [60 x i8] zeroinitializer, align 1 +@.str = private constant [12 x i8] c"abcdefghijk\00" + +; Check cases where slen >= strlen (src). + +define void @test_simplify1() { +; CHECK: @test_simplify1 + %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0 + %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0 + +; CHECK-NEXT: call i8* @stpcpy + call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 60) + ret void +} + +define void @test_simplify2() { +; CHECK: @test_simplify2 + %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0 + %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0 + +; CHECK-NEXT: call i8* @stpcpy + call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 12) + ret void +} + +define void @test_simplify3() { +; CHECK: @test_simplify3 + %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0 + %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0 + +; CHECK-NEXT: call i8* @stpcpy + call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 -1) + ret void +} + +; Check cases where there are no string constants. + +define void @test_simplify4() { +; CHECK: @test_simplify4 + %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0 + %src = getelementptr inbounds [60 x i8]* @b, i32 0, i32 0 + +; CHECK-NEXT: call i8* @stpcpy + call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 -1) + ret void +} + +; Check case where the string length is not constant. + +define i8* @test_simplify5() { +; CHECK: @test_simplify5 + %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0 + %src = getelementptr inbounds [12 x i8]* @.str, i32 0, i32 0 + +; CHECK: @__memcpy_chk + %len = call i32 @llvm.objectsize.i32(i8* %dst, i1 false) + %ret = call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 %len) +; CHECK: ret i8* getelementptr inbounds ([60 x i8]* @a, i32 0, i32 11) + ret i8* %ret +} + +; Check case where the source and destination are the same. + +define i8* @test_simplify6() { +; CHECK: @test_simplify6 + %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0 + +; CHECK: [[LEN:%[a-z]+]] = call i32 @strlen +; CHECK-NEXT: getelementptr inbounds [60 x i8]* @a, i32 0, i32 [[LEN]] + %len = call i32 @llvm.objectsize.i32(i8* %dst, i1 false) + %ret = call i8* @__stpcpy_chk(i8* %dst, i8* %dst, i32 %len) + ret i8* %ret +} + +; Check case where slen < strlen (src). + +define void @test_no_simplify1() { +; CHECK: @test_no_simplify1 + %dst = getelementptr inbounds [60 x i8]* @a, i32 0, i32 0 + %src = getelementptr inbounds [60 x i8]* @b, i32 0, i32 0 + +; CHECK-NEXT: call i8* @__stpcpy_chk + call i8* @__stpcpy_chk(i8* %dst, i8* %src, i32 8) + ret void +} + +declare i8* @__stpcpy_chk(i8*, i8*, i32) nounwind +declare i32 @llvm.objectsize.i32(i8*, i1) nounwind readonly diff --git a/test/Transforms/InstCombine/stpcpy_chk-2.ll b/test/Transforms/InstCombine/stpcpy_chk-2.ll new file mode 100644 index 00000000000..46c2139276e --- /dev/null +++ b/test/Transforms/InstCombine/stpcpy_chk-2.ll @@ -0,0 +1,21 @@ +; Test that lib call simplification doesn't simplify __stpcpy_chk calls +; with the wrong prototype. +; +; RUN: opt < %s -instcombine -S | FileCheck %s + +target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128" + +@a = common global [60 x i16] zeroinitializer, align 1 +@.str = private constant [8 x i8] c"abcdefg\00" + +define void @test_no_simplify() { +; CHECK: @test_no_simplify + %dst = getelementptr inbounds [60 x i16]* @a, i32 0, i32 0 + %src = getelementptr inbounds [8 x i8]* @.str, i32 0, i32 0 + +; CHECK-NEXT: call i16* @__strcpy_chk + call i16* @__strcpy_chk(i16* %dst, i8* %src, i32 8) + ret void +} + +declare i16* @__strcpy_chk(i16*, i8*, i32) -- 2.34.1