DwarfCFIException.cpp revision a432997745f668e85e45826106430f69238b1d1e
1//===-- CodeGen/AsmPrinter/DwarfException.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 DWARF 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/CodeGen/MachineLocation.h" 21#include "llvm/MC/MCAsmInfo.h" 22#include "llvm/MC/MCContext.h" 23#include "llvm/MC/MCExpr.h" 24#include "llvm/MC/MCSection.h" 25#include "llvm/MC/MCStreamer.h" 26#include "llvm/MC/MCSymbol.h" 27#include "llvm/Target/Mangler.h" 28#include "llvm/Target/TargetData.h" 29#include "llvm/Target/TargetFrameLowering.h" 30#include "llvm/Target/TargetLoweringObjectFile.h" 31#include "llvm/Target/TargetMachine.h" 32#include "llvm/Target/TargetOptions.h" 33#include "llvm/Target/TargetRegisterInfo.h" 34#include "llvm/Support/Dwarf.h" 35#include "llvm/Support/ErrorHandling.h" 36#include "llvm/Support/FormattedStream.h" 37#include "llvm/ADT/SmallString.h" 38#include "llvm/ADT/StringExtras.h" 39#include "llvm/ADT/Twine.h" 40using namespace llvm; 41 42DwarfCFIException::DwarfCFIException(AsmPrinter *A) 43 : DwarfException(A), 44 shouldEmitTable(false), shouldEmitMoves(false), shouldEmitTableModule(false) 45 {} 46 47DwarfCFIException::~DwarfCFIException() {} 48 49/// EndModule - Emit all exception information that should come after the 50/// content. 51void DwarfCFIException::EndModule() { 52 if (!Asm->MAI->isExceptionHandlingDwarf()) 53 return; 54 55 if (!shouldEmitTableModule) 56 return; 57 58 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); 59 unsigned PerEncoding = TLOF.getPersonalityEncoding(); 60 61 if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel) 62 return; 63 64 // Emit references to all used personality functions 65 const std::vector<const Function*> &Personalities = MMI->getPersonalities(); 66 for (size_t i = 0, e = Personalities.size(); i != e; ++i) { 67 const MCSymbol *Sym = Asm->Mang->getSymbol(Personalities[i]); 68 TLOF.emitPersonalityValue(Asm->OutStreamer, Asm->TM, Sym); 69 } 70} 71 72/// BeginFunction - Gather pre-function exception information. Assumes it's 73/// being emitted immediately after the function entry point. 74void DwarfCFIException::BeginFunction(const MachineFunction *MF) { 75 shouldEmitTable = shouldEmitMoves = false; 76 77 // If any landing pads survive, we need an EH table. 78 shouldEmitTable = !MMI->getLandingPads().empty(); 79 80 // See if we need frame move info. 81 shouldEmitMoves = Asm->needsCFIMoves(); 82 83 if (shouldEmitMoves || shouldEmitTable) 84 // Assumes in correct section after the entry point. 85 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin", 86 Asm->getFunctionNumber())); 87 88 shouldEmitTableModule |= shouldEmitTable; 89 90 if (shouldEmitMoves || shouldEmitTable) 91 Asm->OutStreamer.EmitCFIStartProc(); 92 93 if (!shouldEmitTable) 94 return; 95 96 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering(); 97 98 // Provide LSDA information. 99 unsigned LSDAEncoding = TLOF.getLSDAEncoding(); 100 if (LSDAEncoding != dwarf::DW_EH_PE_omit) 101 Asm->OutStreamer.EmitCFILsda(Asm->GetTempSymbol("exception", 102 Asm->getFunctionNumber()), 103 LSDAEncoding); 104 105 // Indicate personality routine, if any. 106 unsigned PerEncoding = TLOF.getPersonalityEncoding(); 107 const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()]; 108 if (PerEncoding == dwarf::DW_EH_PE_omit || !Per) 109 return; 110 111 const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang, MMI); 112 Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding); 113} 114 115/// EndFunction - Gather and emit post-function exception information. 116/// 117void DwarfCFIException::EndFunction() { 118 if (!shouldEmitMoves && !shouldEmitTable) return; 119 120 Asm->OutStreamer.EmitCFIEndProc(); 121 122 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end", 123 Asm->getFunctionNumber())); 124 125 // Map all labels and get rid of any dead landing pads. 126 MMI->TidyLandingPads(); 127 128 if (shouldEmitTable) 129 EmitExceptionTable(); 130} 131