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/MC/MCAsmInfo.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCSection.h"
24 #include "llvm/MC/MCStreamer.h"
25 #include "llvm/MC/MCSymbol.h"
26 #include "llvm/Target/Mangler.h"
27 #include "llvm/Target/TargetData.h"
28 #include "llvm/Target/TargetFrameLowering.h"
29 #include "llvm/Target/TargetLoweringObjectFile.h"
30 #include "llvm/Target/TargetMachine.h"
31 #include "llvm/Target/TargetOptions.h"
32 #include "llvm/Target/TargetRegisterInfo.h"
33 #include "llvm/Support/Dwarf.h"
34 #include "llvm/Support/ErrorHandling.h"
35 #include "llvm/Support/FormattedStream.h"
36 #include "llvm/ADT/SmallString.h"
37 #include "llvm/ADT/StringExtras.h"
38 #include "llvm/ADT/Twine.h"
39 using namespace llvm;
40
Win64Exception(AsmPrinter * A)41 Win64Exception::Win64Exception(AsmPrinter *A)
42 : DwarfException(A),
43 shouldEmitPersonality(false), shouldEmitLSDA(false), shouldEmitMoves(false)
44 {}
45
~Win64Exception()46 Win64Exception::~Win64Exception() {}
47
48 /// EndModule - Emit all exception information that should come after the
49 /// content.
EndModule()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.
BeginFunction(const MachineFunction * MF)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 ///
EndFunction()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 }
116