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/Mangler.h"
24#include "llvm/IR/Module.h"
25#include "llvm/MC/MCAsmInfo.h"
26#include "llvm/MC/MCContext.h"
27#include "llvm/MC/MCExpr.h"
28#include "llvm/MC/MCSection.h"
29#include "llvm/MC/MCStreamer.h"
30#include "llvm/MC/MCSymbol.h"
31#include "llvm/Support/Dwarf.h"
32#include "llvm/Support/ErrorHandling.h"
33#include "llvm/Support/FormattedStream.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"
38using namespace llvm;
39
40Win64Exception::Win64Exception(AsmPrinter *A)
41  : EHStreamer(A), shouldEmitPersonality(false), shouldEmitLSDA(false),
42    shouldEmitMoves(false) {}
43
44Win64Exception::~Win64Exception() {}
45
46/// endModule - Emit all exception information that should come after the
47/// content.
48void Win64Exception::endModule() {
49}
50
51/// beginFunction - Gather pre-function exception information. Assumes it's
52/// being emitted immediately after the function entry point.
53void Win64Exception::beginFunction(const MachineFunction *MF) {
54  shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
55
56  // If any landing pads survive, we need an EH table.
57  bool hasLandingPads = !MMI->getLandingPads().empty();
58
59  shouldEmitMoves = Asm->needsSEHMoves();
60
61  const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
62  unsigned PerEncoding = TLOF.getPersonalityEncoding();
63  const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
64
65  shouldEmitPersonality = hasLandingPads &&
66    PerEncoding != dwarf::DW_EH_PE_omit && Per;
67
68  unsigned LSDAEncoding = TLOF.getLSDAEncoding();
69  shouldEmitLSDA = shouldEmitPersonality &&
70    LSDAEncoding != dwarf::DW_EH_PE_omit;
71
72  if (!shouldEmitPersonality && !shouldEmitMoves)
73    return;
74
75  Asm->OutStreamer.EmitWinCFIStartProc(Asm->CurrentFnSym);
76
77  if (!shouldEmitPersonality)
78    return;
79
80  const MCSymbol *PersHandlerSym =
81      TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
82  Asm->OutStreamer.EmitWinEHHandler(PersHandlerSym, true, true);
83
84  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
85                                                Asm->getFunctionNumber()));
86}
87
88/// endFunction - Gather and emit post-function exception information.
89///
90void Win64Exception::endFunction(const MachineFunction *) {
91  if (!shouldEmitPersonality && !shouldEmitMoves)
92    return;
93
94  Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
95                                                Asm->getFunctionNumber()));
96
97  // Map all labels and get rid of any dead landing pads.
98  MMI->TidyLandingPads();
99
100  if (shouldEmitPersonality) {
101    Asm->OutStreamer.PushSection();
102    Asm->OutStreamer.EmitWinEHHandlerData();
103    emitExceptionTable();
104    Asm->OutStreamer.PopSection();
105  }
106  Asm->OutStreamer.EmitWinCFIEndProc();
107}
108