lib/CodeGen/AsmPrinter/Win64Exception.cpp

   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/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"
  40 using namespace llvm;
  41
  42 Win64Exception::Win64Exception(AsmPrinter *A)
  43   : DwarfException(A),
  44     shouldEmitPersonality(false), shouldEmitLSDA(false), shouldEmitMoves(false)
  45     {}
  46
  47 Win64Exception::~Win64Exception() {}
  48
  49 /// EndModule - Emit all exception information that should come after the
  50 /// content.
  51 void Win64Exception::EndModule() {
  52 }
  53
  54 /// BeginFunction - Gather pre-function exception information. Assumes it's
  55 /// being emitted immediately after the function entry point.
  56 void Win64Exception::BeginFunction(const MachineFunction *MF) {
  57   shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
  58
  59   // If any landing pads survive, we need an EH table.
  60   bool hasLandingPads = !MMI->getLandingPads().empty();
  61
  62   shouldEmitMoves = Asm->needsSEHMoves();
  63
  64   const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
  65   unsigned PerEncoding = TLOF.getPersonalityEncoding();
  66   const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
  67
  68   shouldEmitPersonality = hasLandingPads &&
  69     PerEncoding != dwarf::DW_EH_PE_omit && Per;
  70
  71   unsigned LSDAEncoding = TLOF.getLSDAEncoding();
  72   shouldEmitLSDA = shouldEmitPersonality &&
  73     LSDAEncoding != dwarf::DW_EH_PE_omit;
  74
  75   if (!shouldEmitPersonality && !shouldEmitMoves)
  76     return;
  77
  78   Asm->OutStreamer.EmitWin64EHStartProc(Asm->CurrentFnSym);
  79
  80   if (!shouldEmitPersonality)
  81     return;
  82
  83   MCSymbol *GCCHandlerSym =
  84     Asm->GetExternalSymbolSymbol("_GCC_specific_handler");
  85   Asm->OutStreamer.EmitWin64EHHandler(GCCHandlerSym, true, true);
  86
  87   Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
  88                                                 Asm->getFunctionNumber()));
  89 }
  90
  91 /// EndFunction - Gather and emit post-function exception information.
  92 ///
  93 void Win64Exception::EndFunction() {
  94   if (!shouldEmitPersonality && !shouldEmitMoves)
  95     return;
  96
  97   Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
  98                                                 Asm->getFunctionNumber()));
  99
 100   // Map all labels and get rid of any dead landing pads.
 101   MMI->TidyLandingPads();
 102
 103   if (shouldEmitPersonality) {
 104     const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
 105     const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
 106     const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang, MMI);
 107
 108     Asm->OutStreamer.PushSection();
 109     Asm->OutStreamer.EmitWin64EHHandlerData();
 110     Asm->OutStreamer.EmitValue(MCSymbolRefExpr::Create(Sym, Asm->OutContext),
 111                                4);
 112     EmitExceptionTable();
 113     Asm->OutStreamer.PopSection();
 114   }
 115   Asm->OutStreamer.EmitWin64EHEndProc();
 116 }