1 //===-- CodeGen/AsmPrinter/Win64Exception.cpp - Dwarf Exception Impl ------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file contains support for writing Win64 exception info into asm files. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "DwarfException.h" 15 #include "llvm/ADT/SmallString.h" 16 #include "llvm/ADT/StringExtras.h" 17 #include "llvm/ADT/Twine.h" 18 #include "llvm/CodeGen/AsmPrinter.h" 19 #include "llvm/CodeGen/MachineFrameInfo.h" 20 #include "llvm/CodeGen/MachineFunction.h" 21 #include "llvm/CodeGen/MachineModuleInfo.h" 22 #include "llvm/IR/DataLayout.h" 23 #include "llvm/IR/Mangler.h" 24 #include "llvm/IR/Module.h" 25 #include "llvm/MC/MCAsmInfo.h" 26 #include "llvm/MC/MCContext.h" 27 #include "llvm/MC/MCExpr.h" 28 #include "llvm/MC/MCSection.h" 29 #include "llvm/MC/MCStreamer.h" 30 #include "llvm/MC/MCSymbol.h" 31 #include "llvm/Support/Dwarf.h" 32 #include "llvm/Support/ErrorHandling.h" 33 #include "llvm/Support/FormattedStream.h" 34 #include "llvm/Target/TargetFrameLowering.h" 35 #include "llvm/Target/TargetLoweringObjectFile.h" 36 #include "llvm/Target/TargetOptions.h" 37 #include "llvm/Target/TargetRegisterInfo.h" 38 using namespace llvm; 39 40 Win64Exception::Win64Exception(AsmPrinter *A) 41 : EHStreamer(A), shouldEmitPersonality(false), shouldEmitLSDA(false), 42 shouldEmitMoves(false) {} 43 44 Win64Exception::~Win64Exception() {} 45 46 /// endModule - Emit all exception information that should come after the 47 /// content. 48 void Win64Exception::endModule() { 49 } 50 51 /// beginFunction - Gather pre-function exception information. Assumes it's 52 /// being emitted immediately after the function entry point. 53 void Win64Exception::beginFunction(const MachineFunction *MF) { 54 shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false; 55 56 // If any landing pads survive, we need an EH table. 57 bool hasLandingPads = !MMI->getLandingPads().empty(); 58 59 shouldEmitMoves = Asm->needsSEHMoves(); 60 61 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); 62 unsigned PerEncoding = TLOF.getPersonalityEncoding(); 63 const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()]; 64 65 shouldEmitPersonality = hasLandingPads && 66 PerEncoding != dwarf::DW_EH_PE_omit && Per; 67 68 unsigned LSDAEncoding = TLOF.getLSDAEncoding(); 69 shouldEmitLSDA = shouldEmitPersonality && 70 LSDAEncoding != dwarf::DW_EH_PE_omit; 71 72 if (!shouldEmitPersonality && !shouldEmitMoves) 73 return; 74 75 Asm->OutStreamer.EmitWinCFIStartProc(Asm->CurrentFnSym); 76 77 if (!shouldEmitPersonality) 78 return; 79 80 const MCSymbol *PersHandlerSym = 81 TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI); 82 Asm->OutStreamer.EmitWinEHHandler(PersHandlerSym, true, true); 83 84 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin", 85 Asm->getFunctionNumber())); 86 } 87 88 /// endFunction - Gather and emit post-function exception information. 89 /// 90 void Win64Exception::endFunction(const MachineFunction *) { 91 if (!shouldEmitPersonality && !shouldEmitMoves) 92 return; 93 94 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end", 95 Asm->getFunctionNumber())); 96 97 // Map all labels and get rid of any dead landing pads. 98 MMI->TidyLandingPads(); 99 100 if (shouldEmitPersonality) { 101 Asm->OutStreamer.PushSection(); 102 Asm->OutStreamer.EmitWinEHHandlerData(); 103 emitExceptionTable(); 104 Asm->OutStreamer.PopSection(); 105 } 106 Asm->OutStreamer.EmitWinCFIEndProc(); 107 } 108