diff --git a/include/llvm/CodeGen/MachineModuleInfo.h b/include/llvm/CodeGen/MachineModuleInfo.h index 026c1602210..71ec90a9f2e 100644 --- a/include/llvm/CodeGen/MachineModuleInfo.h +++ b/include/llvm/CodeGen/MachineModuleInfo.h @@ -35,6 +35,7 @@ #include "llvm/Support/DataTypes.h" #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/UniqueVector.h" +#include "llvm/ADT/SmallPtrSet.h" #include "llvm/GlobalValue.h" #include "llvm/Pass.h" @@ -1037,6 +1038,10 @@ private: // common EH frames. std::vector Personalities; + // UsedFunctions - the functions in the llvm.used list in a more easily + // searchable format. + SmallPtrSet UsedFunctions; + bool CallsEHReturn; bool CallsUnwindInit; public: @@ -1235,6 +1240,11 @@ public: return Personalities; } + // UsedFunctions - Return set of the functions in the llvm.used list. + const SmallPtrSet& getUsedFunctions() const { + return UsedFunctions; + } + /// addCatchTypeInfo - Provide the catch typeinfo for a landing pad. /// void addCatchTypeInfo(MachineBasicBlock *LandingPad, diff --git a/lib/CodeGen/DwarfWriter.cpp b/lib/CodeGen/DwarfWriter.cpp index 8b315be7a55..1068f689912 100644 --- a/lib/CodeGen/DwarfWriter.cpp +++ b/lib/CodeGen/DwarfWriter.cpp @@ -2764,15 +2764,14 @@ private: bool hasCalls; bool hasLandingPads; std::vector Moves; - Function::LinkageTypes linkage; + const Function * function; FunctionEHFrameInfo(const std::string &FN, unsigned Num, unsigned P, bool hC, bool hL, const std::vector &M, - Function::LinkageTypes l): + const Function *f): FnName(FN), Number(Num), PersonalityIndex(P), - hasCalls(hC), hasLandingPads(hL), Moves(M), - linkage(l) { } + hasCalls(hC), hasLandingPads(hL), Moves(M), function (f) { } }; std::vector EHFrames; @@ -2869,19 +2868,21 @@ private: /// EmitEHFrame - Emit function exception frame information. /// void EmitEHFrame(const FunctionEHFrameInfo &EHFrameInfo) { + Function::LinkageTypes linkage = EHFrameInfo.function->getLinkage(); + Asm->SwitchToTextSection(TAI->getDwarfEHFrameSection()); // Externally visible entry into the functions eh frame info. // If the corresponding function is static, this should not be // externally visible. - if (EHFrameInfo.linkage != Function::InternalLinkage) { + if (linkage != Function::InternalLinkage) { if (const char *GlobalEHDirective = TAI->getGlobalEHDirective()) O << GlobalEHDirective << EHFrameInfo.FnName << "\n"; } // If corresponding function is weak definition, this should be too. - if ((EHFrameInfo.linkage == Function::WeakLinkage || - EHFrameInfo.linkage == Function::LinkOnceLinkage) && + if ((linkage == Function::WeakLinkage || + linkage == Function::LinkOnceLinkage) && TAI->getWeakDefDirective()) O << TAI->getWeakDefDirective() << EHFrameInfo.FnName << "\n"; @@ -2889,12 +2890,17 @@ private: // omit the EH Frame, but some environments do not handle weak absolute // symbols. if (!EHFrameInfo.hasCalls && - ((EHFrameInfo.linkage != Function::WeakLinkage && - EHFrameInfo.linkage != Function::LinkOnceLinkage) || + ((linkage != Function::WeakLinkage && + linkage != Function::LinkOnceLinkage) || !TAI->getWeakDefDirective() || TAI->getSupportsWeakOmittedEHFrame())) { O << EHFrameInfo.FnName << " = 0\n"; + // This name has no connection to the function, so it might get + // dead-stripped when the function is not, erroneously. Prohibit + // dead-stripping unconditionally. + if (const char *UsedDirective = TAI->getUsedDirective()) + O << UsedDirective << EHFrameInfo.FnName << "\n\n"; } else { O << EHFrameInfo.FnName << ":\n"; @@ -2941,10 +2947,16 @@ private: Asm->EmitAlignment(2); EmitLabel("eh_frame_end", EHFrameInfo.Number); - } - if (const char *UsedDirective = TAI->getUsedDirective()) - O << UsedDirective << EHFrameInfo.FnName << "\n\n"; + // If the function is marked used, this table should be also. We cannot + // make the mark unconditional in this case, since retaining the table + // also retains the function in this case, and there is code around + // that depends on unused functions (calling undefined externals) being + // dead-stripped to link correctly. Yes, there really is. + if (MMI->getUsedFunctions().count(EHFrameInfo.function)) + if (const char *UsedDirective = TAI->getUsedDirective()) + O << UsedDirective << EHFrameInfo.FnName << "\n\n"; + } } /// EmitExceptionTable - Emit landing pads and actions. @@ -3414,7 +3426,7 @@ public: MF->getFrameInfo()->hasCalls(), !MMI->getLandingPads().empty(), MMI->getFrameMoves(), - MF->getFunction()->getLinkage())); + MF->getFunction())); } }; diff --git a/lib/CodeGen/MachineModuleInfo.cpp b/lib/CodeGen/MachineModuleInfo.cpp index f8796acaef7..5e6d4cb4961 100644 --- a/lib/CodeGen/MachineModuleInfo.cpp +++ b/lib/CodeGen/MachineModuleInfo.cpp @@ -1552,6 +1552,21 @@ bool MachineModuleInfo::Verify(Value *V) { /// void MachineModuleInfo::AnalyzeModule(Module &M) { SetupCompileUnits(M); + + // Insert functions in the llvm.used array into UsedFunctions. + GlobalVariable *GV = M.getGlobalVariable("llvm.used"); + if (!GV || !GV->hasInitializer()) return; + + // Should be an array of 'i8*'. + ConstantArray *InitList = dyn_cast(GV->getInitializer()); + if (InitList == 0) return; + + for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) { + if (ConstantExpr *CE = dyn_cast(InitList->getOperand(i))) + if (CE->getOpcode() == Instruction::BitCast) + if (Function *F = dyn_cast(CE->getOperand(0))) + UsedFunctions.insert(F); + } } /// needsFrameInfo - Returns true if we need to gather callee-saved register