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