1 //===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains support for writing DWARF exception info into asm files.
12 //===----------------------------------------------------------------------===//
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/MC/MachineLocation.h"
32 #include "llvm/Support/Dwarf.h"
33 #include "llvm/Support/ErrorHandling.h"
34 #include "llvm/Support/FormattedStream.h"
35 #include "llvm/Target/TargetFrameLowering.h"
36 #include "llvm/Target/TargetLoweringObjectFile.h"
37 #include "llvm/Target/TargetMachine.h"
38 #include "llvm/Target/TargetOptions.h"
39 #include "llvm/Target/TargetRegisterInfo.h"
42 DwarfCFIException::DwarfCFIException(AsmPrinter *A)
43 : EHStreamer(A), shouldEmitPersonality(false), shouldEmitLSDA(false),
44 shouldEmitMoves(false), moveTypeModule(AsmPrinter::CFI_M_None) {}
46 DwarfCFIException::~DwarfCFIException() {}
48 /// endModule - Emit all exception information that should come after the
50 void DwarfCFIException::endModule() {
51 if (moveTypeModule == AsmPrinter::CFI_M_Debug)
52 Asm->OutStreamer.EmitCFISections(false, true);
54 if (!Asm->MAI->isExceptionHandlingDwarf())
57 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
59 unsigned PerEncoding = TLOF.getPersonalityEncoding();
61 if ((PerEncoding & 0x80) != dwarf::DW_EH_PE_indirect)
64 // Emit references to all used personality functions
65 const std::vector<const Function*> &Personalities = MMI->getPersonalities();
66 for (size_t i = 0, e = Personalities.size(); i != e; ++i) {
67 if (!Personalities[i])
69 MCSymbol *Sym = Asm->getSymbol(Personalities[i]);
70 TLOF.emitPersonalityValue(Asm->OutStreamer, Asm->TM, Sym);
74 /// beginFunction - Gather pre-function exception information. Assumes it's
75 /// being emitted immediately after the function entry point.
76 void DwarfCFIException::beginFunction(const MachineFunction *MF) {
77 shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
79 // If any landing pads survive, we need an EH table.
80 bool hasLandingPads = !MMI->getLandingPads().empty();
82 // See if we need frame move info.
83 AsmPrinter::CFIMoveType MoveType = Asm->needsCFIMoves();
84 if (MoveType == AsmPrinter::CFI_M_EH ||
85 (MoveType == AsmPrinter::CFI_M_Debug &&
86 moveTypeModule == AsmPrinter::CFI_M_None))
87 moveTypeModule = MoveType;
89 shouldEmitMoves = MoveType != AsmPrinter::CFI_M_None;
91 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
92 unsigned PerEncoding = TLOF.getPersonalityEncoding();
93 const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
95 shouldEmitPersonality = hasLandingPads &&
96 PerEncoding != dwarf::DW_EH_PE_omit && Per;
98 unsigned LSDAEncoding = TLOF.getLSDAEncoding();
99 shouldEmitLSDA = shouldEmitPersonality &&
100 LSDAEncoding != dwarf::DW_EH_PE_omit;
102 if (!shouldEmitPersonality && !shouldEmitMoves)
105 Asm->OutStreamer.EmitCFIStartProc(/*IsSimple=*/false);
107 // Indicate personality routine, if any.
108 if (!shouldEmitPersonality)
111 const MCSymbol *Sym =
112 TLOF.getCFIPersonalitySymbol(Per, *Asm->Mang, Asm->TM, MMI);
113 Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
116 Asm->GetTempSymbol("eh_func_begin", Asm->getFunctionNumber());
117 if (Asm->MAI->useAssignmentForEHBegin()) {
118 MCContext &Ctx = Asm->OutContext;
119 MCSymbol *CurPos = Ctx.CreateTempSymbol();
120 Asm->OutStreamer.EmitLabel(CurPos);
121 Asm->OutStreamer.EmitAssignment(EHBegin,
122 MCSymbolRefExpr::Create(CurPos, Ctx));
124 Asm->OutStreamer.EmitLabel(EHBegin);
127 // Provide LSDA information.
131 Asm->OutStreamer.EmitCFILsda(Asm->GetTempSymbol("exception",
132 Asm->getFunctionNumber()),
136 /// endFunction - Gather and emit post-function exception information.
138 void DwarfCFIException::endFunction(const MachineFunction *) {
139 if (!shouldEmitPersonality && !shouldEmitMoves)
142 Asm->OutStreamer.EmitCFIEndProc();
144 if (!shouldEmitPersonality)
147 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
148 Asm->getFunctionNumber()));
150 // Map all labels and get rid of any dead landing pads.
151 MMI->TidyLandingPads();
153 emitExceptionTable();