diff options
Diffstat (limited to 'lib/CodeGen')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp | 34 | ||||
| -rw-r--r-- | lib/CodeGen/StackSlotColoring.cpp | 42 |
2 files changed, 37 insertions, 39 deletions
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp index 7e40cb9c64..6d789a674c 100644 --- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp +++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp @@ -25,7 +25,6 @@ #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" @@ -254,39 +253,6 @@ 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(); diff --git a/lib/CodeGen/StackSlotColoring.cpp b/lib/CodeGen/StackSlotColoring.cpp index 354878aa42..8043556349 100644 --- a/lib/CodeGen/StackSlotColoring.cpp +++ b/lib/CodeGen/StackSlotColoring.cpp @@ -118,6 +118,7 @@ namespace { private: void InitializeSlots(); + bool CheckForSetJmpCall(const MachineFunction &MF) const; void ScanForSpillSlotRefs(MachineFunction &MF); bool OverlapWithAssignments(LiveInterval *li, int Color) const; int ColorSlot(LiveInterval *li); @@ -161,6 +162,34 @@ namespace { }; } +/// CheckForSetJmpCall - Return true if there's a call to setjmp/sigsetjmp in +/// this function. +bool StackSlotColoring::CheckForSetJmpCall(const MachineFunction &MF) const { + const Function *F = MF.getFunction(); + const Module *M = F->getParent(); + const Function *SetJmp = M->getFunction("setjmp"); + const Function *SigSetJmp = M->getFunction("sigsetjmp"); + + if (!SetJmp && !SigSetJmp) + return false; + + 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() == F) + return true; + + if (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() == F) + return true; + + return false; +} + /// ScanForSpillSlotRefs - Scan all the machine instructions for spill slot /// references and update spill slot weights. void StackSlotColoring::ScanForSpillSlotRefs(MachineFunction &MF) { @@ -724,11 +753,14 @@ bool StackSlotColoring::runOnMachineFunction(MachineFunction &MF) { return false; } - // If there is a call to a function with the attribute "returns_twice" (like - // setjmp or sigsetjmp), don't perform stack slot coloring. The stack could be - // modified before the the second return, resulting in the wrong value being - // used afterwards. (See <rdar://problem/8007500>.) - if (MF.hasReturnsTwiceCall()) + // If there are calls to setjmp or sigsetjmp, don't perform stack slot + // coloring. The stack could be modified before the longjmp is executed, + // resulting in the wrong value being used afterwards. (See + // <rdar://problem/8007500>.) + // + // FIXME: This goes beyond the setjmp/sigsetjmp functions. Ideally, we should + // check for the GCC "returns twice" attribute. + if (CheckForSetJmpCall(MF)) return false; // Gather spill slot references |