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author | Bill Wendling <isanbard@gmail.com> | 2010-05-26 00:32:40 +0000 |
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committer | Bill Wendling <isanbard@gmail.com> | 2010-05-26 00:32:40 +0000 |
commit | be22683202731127a5128db8be404edcee91defd (patch) | |
tree | 4cdd751a636f97cf2243eed3b1e65cdfde26b64f /lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | |
parent | 6a45d681e53a99b4c4f63e0b1664626a596a8151 (diff) | |
download | external_llvm-be22683202731127a5128db8be404edcee91defd.zip external_llvm-be22683202731127a5128db8be404edcee91defd.tar.gz external_llvm-be22683202731127a5128db8be404edcee91defd.tar.bz2 |
Dale and Evan suggested putting the "check for setjmp" much earlier in the
machine code generation. That's a good idea, so I made it so.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104655 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp')
-rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 34 |
1 files changed, 34 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 6d789a6..7e40cb9 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -25,6 +25,7 @@ #include "llvm/Intrinsics.h" #include "llvm/IntrinsicInst.h" #include "llvm/LLVMContext.h" +#include "llvm/Module.h" #include "llvm/CodeGen/FastISel.h" #include "llvm/CodeGen/GCStrategy.h" #include "llvm/CodeGen/GCMetadata.h" @@ -253,6 +254,39 @@ bool SelectionDAGISel::runOnMachineFunction(MachineFunction &mf) { done:; } + // Set a flag indicating if the machine function makes a call to setjmp / + // sigsetjmp (i.e., a function marked "returns_twice"). We'll use this to + // disable certain optimizations which cannot handle such control flows. + // + // FIXME: This goes beyond the setjmp/sigsetjmp functions. We should check for + // the GCC "returns twice" attribute. + const Module *M = Fn.getParent(); + const Function *SetJmp = M->getFunction("setjmp"); + const Function *SigSetJmp = M->getFunction("sigsetjmp"); + bool HasReturnsTwiceCall = false; + + if (SetJmp || SigSetJmp) { + if (SetJmp && !SetJmp->use_empty()) + for (Value::const_use_iterator + I = SetJmp->use_begin(), E = SetJmp->use_end(); I != E; ++I) + if (const CallInst *CI = dyn_cast<CallInst>(I)) + if (CI->getParent()->getParent() == &Fn) { + HasReturnsTwiceCall = true; + break; + } + + if (!HasReturnsTwiceCall && SigSetJmp && !SigSetJmp->use_empty()) + for (Value::const_use_iterator + I = SigSetJmp->use_begin(), E = SigSetJmp->use_end(); I != E; ++I) + if (const CallInst *CI = dyn_cast<CallInst>(I)) + if (CI->getParent()->getParent() == &Fn) { + HasReturnsTwiceCall = true; + break; + } + + mf.setReturnsTwiceCall(HasReturnsTwiceCall); + } + // Release function-specific state. SDB and CurDAG are already cleared // at this point. FuncInfo->clear(); |