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/Module.h" 16 #include "llvm/CodeGen/AsmPrinter.h" 17 #include "llvm/CodeGen/MachineModuleInfo.h" 18 #include "llvm/CodeGen/MachineFrameInfo.h" 19 #include "llvm/CodeGen/MachineFunction.h" 20 #include "llvm/MC/MCAsmInfo.h" 21 #include "llvm/MC/MCContext.h" 22 #include "llvm/MC/MCExpr.h" 23 #include "llvm/MC/MCSection.h" 24 #include "llvm/MC/MCStreamer.h" 25 #include "llvm/MC/MCSymbol.h" 26 #include "llvm/Target/Mangler.h" 27 #include "llvm/Target/TargetData.h" 28 #include "llvm/Target/TargetFrameLowering.h" 29 #include "llvm/Target/TargetLoweringObjectFile.h" 30 #include "llvm/Target/TargetMachine.h" 31 #include "llvm/Target/TargetOptions.h" 32 #include "llvm/Target/TargetRegisterInfo.h" 33 #include "llvm/Support/Dwarf.h" 34 #include "llvm/Support/ErrorHandling.h" 35 #include "llvm/Support/FormattedStream.h" 36 #include "llvm/ADT/SmallString.h" 37 #include "llvm/ADT/StringExtras.h" 38 #include "llvm/ADT/Twine.h" 39 using namespace llvm; 40 41 Win64Exception::Win64Exception(AsmPrinter *A) 42 : DwarfException(A), 43 shouldEmitPersonality(false), shouldEmitLSDA(false), shouldEmitMoves(false) 44 {} 45 46 Win64Exception::~Win64Exception() {} 47 48 /// EndModule - Emit all exception information that should come after the 49 /// content. 50 void Win64Exception::EndModule() { 51 } 52 53 /// BeginFunction - Gather pre-function exception information. Assumes it's 54 /// being emitted immediately after the function entry point. 55 void Win64Exception::BeginFunction(const MachineFunction *MF) { 56 shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false; 57 58 // If any landing pads survive, we need an EH table. 59 bool hasLandingPads = !MMI->getLandingPads().empty(); 60 61 shouldEmitMoves = Asm->needsSEHMoves(); 62 63 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); 64 unsigned PerEncoding = TLOF.getPersonalityEncoding(); 65 const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()]; 66 67 shouldEmitPersonality = hasLandingPads && 68 PerEncoding != dwarf::DW_EH_PE_omit && Per; 69 70 unsigned LSDAEncoding = TLOF.getLSDAEncoding(); 71 shouldEmitLSDA = shouldEmitPersonality && 72 LSDAEncoding != dwarf::DW_EH_PE_omit; 73 74 if (!shouldEmitPersonality && !shouldEmitMoves) 75 return; 76 77 Asm->OutStreamer.EmitWin64EHStartProc(Asm->CurrentFnSym); 78 79 if (!shouldEmitPersonality) 80 return; 81 82 MCSymbol *GCCHandlerSym = 83 Asm->GetExternalSymbolSymbol("_GCC_specific_handler"); 84 Asm->OutStreamer.EmitWin64EHHandler(GCCHandlerSym, true, true); 85 86 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin", 87 Asm->getFunctionNumber())); 88 } 89 90 /// EndFunction - Gather and emit post-function exception information. 91 /// 92 void Win64Exception::EndFunction() { 93 if (!shouldEmitPersonality && !shouldEmitMoves) 94 return; 95 96 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end", 97 Asm->getFunctionNumber())); 98 99 // Map all labels and get rid of any dead landing pads. 100 MMI->TidyLandingPads(); 101 102 if (shouldEmitPersonality) { 103 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); 104 const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()]; 105 const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang, MMI); 106 107 Asm->OutStreamer.PushSection(); 108 Asm->OutStreamer.EmitWin64EHHandlerData(); 109 Asm->OutStreamer.EmitValue(MCSymbolRefExpr::Create(Sym, Asm->OutContext), 110 4); 111 EmitExceptionTable(); 112 Asm->OutStreamer.PopSection(); 113 } 114 Asm->OutStreamer.EmitWin64EHEndProc(); 115 } 116