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
Win64Exception(AsmPrinter * A)40 Win64Exception::Win64Exception(AsmPrinter *A)
41 : DwarfException(A),
42 shouldEmitPersonality(false), shouldEmitLSDA(false), shouldEmitMoves(false)
43 {}
44
~Win64Exception()45 Win64Exception::~Win64Exception() {}
46
47 /// EndModule - Emit all exception information that should come after the
48 /// content.
EndModule()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.
BeginFunction(const MachineFunction * MF)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 ///
EndFunction()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 }
115