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/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/DataLayout.h"
  23 #include "llvm/MC/MCAsmInfo.h"
  24 #include "llvm/MC/MCContext.h"
  25 #include "llvm/MC/MCExpr.h"
  26 #include "llvm/MC/MCSection.h"
  27 #include "llvm/MC/MCStreamer.h"
  28 #include "llvm/MC/MCSymbol.h"
  29 #include "llvm/Module.h"
  30 #include "llvm/Support/Dwarf.h"
  31 #include "llvm/Support/ErrorHandling.h"
  32 #include "llvm/Support/FormattedStream.h"
  33 #include "llvm/Target/Mangler.h"
  34 #include "llvm/Target/TargetFrameLowering.h"
  35 #include "llvm/Target/TargetLoweringObjectFile.h"
  36 #include "llvm/Target/TargetMachine.h"
  37 #include "llvm/Target/TargetOptions.h"
  38 #include "llvm/Target/TargetRegisterInfo.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 }