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/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/CodeGen/MachineLocation.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCContext.h"
23 #include "llvm/MC/MCExpr.h"
24 #include "llvm/MC/MCSection.h"
25 #include "llvm/MC/MCStreamer.h"
26 #include "llvm/MC/MCSymbol.h"
27 #include "llvm/Target/Mangler.h"
28 #include "llvm/Target/TargetData.h"
29 #include "llvm/Target/TargetFrameLowering.h"
30 #include "llvm/Target/TargetLoweringObjectFile.h"
31 #include "llvm/Target/TargetMachine.h"
32 #include "llvm/Target/TargetOptions.h"
33 #include "llvm/Target/TargetRegisterInfo.h"
34 #include "llvm/Support/Dwarf.h"
35 #include "llvm/Support/ErrorHandling.h"
36 #include "llvm/Support/FormattedStream.h"
37 #include "llvm/ADT/SmallString.h"
38 #include "llvm/ADT/StringExtras.h"
39 #include "llvm/ADT/Twine.h"
42 DwarfCFIException::DwarfCFIException(AsmPrinter *A)
44 shouldEmitPersonality(false), shouldEmitLSDA(false), shouldEmitMoves(false)
47 DwarfCFIException::~DwarfCFIException() {}
49 /// EndModule - Emit all exception information that should come after the
51 void DwarfCFIException::EndModule() {
52 if (!Asm->MAI->isExceptionHandlingDwarf())
55 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
56 unsigned PerEncoding = TLOF.getPersonalityEncoding();
58 if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel)
61 // Emit references to all used personality functions
62 const std::vector<const Function*> &Personalities = MMI->getPersonalities();
63 for (size_t i = 0, e = Personalities.size(); i != e; ++i) {
64 if (!Personalities[i])
66 MCSymbol *Sym = Asm->Mang->getSymbol(Personalities[i]);
67 TLOF.emitPersonalityValue(Asm->OutStreamer, Asm->TM, Sym);
71 /// BeginFunction - Gather pre-function exception information. Assumes it's
72 /// being emitted immediately after the function entry point.
73 void DwarfCFIException::BeginFunction(const MachineFunction *MF) {
74 shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
76 // If any landing pads survive, we need an EH table.
77 bool hasLandingPads = !MMI->getLandingPads().empty();
79 // See if we need frame move info.
80 shouldEmitMoves = Asm->needsCFIMoves();
82 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
83 unsigned PerEncoding = TLOF.getPersonalityEncoding();
84 const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
86 shouldEmitPersonality = hasLandingPads &&
87 PerEncoding != dwarf::DW_EH_PE_omit && Per;
89 unsigned LSDAEncoding = TLOF.getLSDAEncoding();
90 shouldEmitLSDA = shouldEmitPersonality &&
91 LSDAEncoding != dwarf::DW_EH_PE_omit;
93 if (!shouldEmitPersonality && !shouldEmitMoves)
96 Asm->OutStreamer.EmitCFIStartProc();
98 // Indicate personality routine, if any.
99 if (!shouldEmitPersonality)
102 const MCSymbol *Sym = TLOF.getCFIPersonalitySymbol(Per, Asm->Mang, MMI);
103 Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
105 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
106 Asm->getFunctionNumber()));
108 // Provide LSDA information.
112 Asm->OutStreamer.EmitCFILsda(Asm->GetTempSymbol("exception",
113 Asm->getFunctionNumber()),
117 /// EndFunction - Gather and emit post-function exception information.
119 void DwarfCFIException::EndFunction() {
120 if (!shouldEmitPersonality && !shouldEmitMoves)
123 Asm->OutStreamer.EmitCFIEndProc();
125 Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
126 Asm->getFunctionNumber()));
128 // Map all labels and get rid of any dead landing pads.
129 MMI->TidyLandingPads();
131 if (shouldEmitPersonality)
132 EmitExceptionTable();