Win64Exception.cpp revision 0b8c9a80f20772c3793201ab5b251d3520b9cea3 
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/TargetMachine.h"
37#include "llvm/Target/TargetOptions.h"
38#include "llvm/Target/TargetRegisterInfo.h"
39using namespace llvm;
40
41Win64Exception::Win64Exception(AsmPrinter *A)
42  : DwarfException(A),
43    shouldEmitPersonality(false), shouldEmitLSDA(false), shouldEmitMoves(false)
44    {}
45
46Win64Exception::~Win64Exception() {}
47
48/// EndModule - Emit all exception information that should come after the
49/// content.
50void Win64Exception::EndModule() {
51}
52
53/// BeginFunction - Gather pre-function exception information. Assumes it's
54/// being emitted immediately after the function entry point.
55void 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///
92void 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