From 8e4847ee957a7c7c434a72fdb7a6010004ca86f4 Mon Sep 17 00:00:00 2001 From: Duncan Sands Date: Sun, 16 Dec 2007 15:51:49 +0000 Subject: [PATCH] Make instcombine promote inline asm calls to 'nounwind' calls. Remove special casing of inline asm from the inliner. There is a potential problem: the verifier rejects invokes of inline asm (not sure why). If an asm call is not marked "nounwind" in some .ll, and instcombine is not run, but the inliner is run, then an illegal module will be created. This is bad but I'm not sure what the best approach is. I'm tempted to remove the check in the verifier... llvm-svn: 45073 --- llvm/include/llvm/Support/CallSite.h | 3 +++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 13 +++++++++++++ llvm/lib/Transforms/Utils/InlineFunction.cpp | 5 ++--- llvm/lib/VMCore/Instructions.cpp | 6 ++++++ llvm/test/CFrontend/2007-12-16-AsmNoUnwind.c | 3 +++ llvm/test/Transforms/Inline/2007-04-15-InlineEH.ll | 2 +- .../InstCombine/2007-12-16-AsmNoUnwind.ll | 7 +++++++ 7 files changed, 35 insertions(+), 4 deletions(-) create mode 100644 llvm/test/CFrontend/2007-12-16-AsmNoUnwind.c create mode 100644 llvm/test/Transforms/InstCombine/2007-12-16-AsmNoUnwind.ll diff --git a/llvm/include/llvm/Support/CallSite.h b/llvm/include/llvm/Support/CallSite.h index 5bb60a8a8af9..3735842e7244 100644 --- a/llvm/include/llvm/Support/CallSite.h +++ b/llvm/include/llvm/Support/CallSite.h @@ -73,6 +73,9 @@ public: /// @brief Determine if the call does not access or only reads memory. bool onlyReadsMemory() const; + /// @brief Determine if the call cannot unwind. + bool isNoUnwind() const; + /// getType - Return the type of the instruction that generated this call site /// const Type *getType() const { return I->getType(); } diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 653d35e34f49..aa9e932fc527 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -7972,6 +7972,19 @@ Instruction *InstCombiner::visitCallSite(CallSite CS) { } } + if (isa(Callee) && !CS.isNoUnwind()) { + // Inline asm calls cannot throw - mark them 'nounwind'. + const ParamAttrsList *PAL = CS.getParamAttrs(); + uint16_t RAttributes = PAL ? PAL->getParamAttrs(0) : 0; + RAttributes |= ParamAttr::NoUnwind; + + ParamAttrsVector modVec; + modVec.push_back(ParamAttrsWithIndex::get(0, RAttributes)); + PAL = ParamAttrsList::getModified(PAL, modVec); + CS.setParamAttrs(PAL); + Changed = true; + } + return Changed ? CS.getInstruction() : 0; } diff --git a/llvm/lib/Transforms/Utils/InlineFunction.cpp b/llvm/lib/Transforms/Utils/InlineFunction.cpp index e9f6b28e98b5..3d31f71300ac 100644 --- a/llvm/lib/Transforms/Utils/InlineFunction.cpp +++ b/llvm/lib/Transforms/Utils/InlineFunction.cpp @@ -69,9 +69,8 @@ static void HandleInlinedInvoke(InvokeInst *II, BasicBlock *FirstNewBlock, if (!isa(I)) continue; CallInst *CI = cast(I); - // If this call cannot unwind or is an inline asm, don't - // convert it to an invoke. - if (CI->isNoUnwind() || isa(CI->getCalledValue())) + // If this call cannot unwind, don't convert it to an invoke. + if (CI->isNoUnwind()) continue; // Convert this function call into an invoke instruction. diff --git a/llvm/lib/VMCore/Instructions.cpp b/llvm/lib/VMCore/Instructions.cpp index 5207ea52f493..511a0e851a10 100644 --- a/llvm/lib/VMCore/Instructions.cpp +++ b/llvm/lib/VMCore/Instructions.cpp @@ -65,6 +65,12 @@ bool CallSite::onlyReadsMemory() const { else return cast(I)->onlyReadsMemory(); } +bool CallSite::isNoUnwind() const { + if (CallInst *CI = dyn_cast(I)) + return CI->isNoUnwind(); + else + return cast(I)->isNoUnwind(); +} diff --git a/llvm/test/CFrontend/2007-12-16-AsmNoUnwind.c b/llvm/test/CFrontend/2007-12-16-AsmNoUnwind.c new file mode 100644 index 000000000000..b080e6a511e8 --- /dev/null +++ b/llvm/test/CFrontend/2007-12-16-AsmNoUnwind.c @@ -0,0 +1,3 @@ +// RUN: %llvmgcc %s -S -o - | grep nounwind + +void bar() { asm (""); } diff --git a/llvm/test/Transforms/Inline/2007-04-15-InlineEH.ll b/llvm/test/Transforms/Inline/2007-04-15-InlineEH.ll index 73b0e215e8c5..9d28755d2890 100644 --- a/llvm/test/Transforms/Inline/2007-04-15-InlineEH.ll +++ b/llvm/test/Transforms/Inline/2007-04-15-InlineEH.ll @@ -8,7 +8,7 @@ target triple = "i686-pc-linux-gnu" define void @bc__support__high_resolution_time__clock() { entry: - call void asm "rdtsc\0A\09movl %eax, $0\0A\09movl %edx, $1", "=*imr,=*imr,~{dirflag},~{fpsr},~{flags},~{dx},~{ax}"( i32* null, i32* null ) + call void asm "rdtsc\0A\09movl %eax, $0\0A\09movl %edx, $1", "=*imr,=*imr,~{dirflag},~{fpsr},~{flags},~{dx},~{ax}"( i32* null, i32* null ) nounwind unreachable } diff --git a/llvm/test/Transforms/InstCombine/2007-12-16-AsmNoUnwind.ll b/llvm/test/Transforms/InstCombine/2007-12-16-AsmNoUnwind.ll new file mode 100644 index 000000000000..336c6d5a2eba --- /dev/null +++ b/llvm/test/Transforms/InstCombine/2007-12-16-AsmNoUnwind.ll @@ -0,0 +1,7 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep nounwind + +define void @bar() { +entry: + call void asm sideeffect "", "~{dirflag},~{fpsr},~{flags}"( ) + ret void +}