1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
//===-- CodeGen/AsmPrinter/DwarfException.cpp - Dwarf Exception Impl ------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains support for writing DWARF exception info into asm files.
//
//===----------------------------------------------------------------------===//
#include "DwarfException.h"
#include "llvm/Module.h"
#include "llvm/CodeGen/AsmPrinter.h"
#include "llvm/CodeGen/MachineModuleInfo.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineLocation.h"
#include "llvm/MC/MCAsmInfo.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCExpr.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/Target/Mangler.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Target/TargetFrameLowering.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
#include "llvm/Target/TargetRegisterInfo.h"
#include "llvm/Support/Dwarf.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/Twine.h"
using namespace llvm;
DwarfCFIException::DwarfCFIException(AsmPrinter *A)
: DwarfException(A),
shouldEmitTable(false), shouldEmitMoves(false), shouldEmitTableModule(false)
{}
DwarfCFIException::~DwarfCFIException() {}
/// EndModule - Emit all exception information that should come after the
/// content.
void DwarfCFIException::EndModule() {
if (!Asm->MAI->isExceptionHandlingDwarf())
return;
if (!shouldEmitTableModule)
return;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
unsigned PerEncoding = TLOF.getPersonalityEncoding();
// Begin eh frame section.
Asm->OutStreamer.SwitchSection(TLOF.getEHFrameSection());
if ((PerEncoding & 0x70) != dwarf::DW_EH_PE_pcrel)
return;
// Emit references to all used personality functions
const std::vector<const Function*> &Personalities = MMI->getPersonalities();
for (size_t i = 0, e = Personalities.size(); i != e; ++i) {
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("personality", i));
const MCSymbol *Sym = Asm->Mang->getSymbol(Personalities[i]);
unsigned Size = Asm->TM.getTargetData()->getPointerSize();
Asm->OutStreamer.EmitSymbolValue(Sym, Size);
}
}
/// BeginFunction - Gather pre-function exception information. Assumes it's
/// being emitted immediately after the function entry point.
void DwarfCFIException::BeginFunction(const MachineFunction *MF) {
shouldEmitTable = shouldEmitMoves = false;
// If any landing pads survive, we need an EH table.
shouldEmitTable = !MMI->getLandingPads().empty();
// See if we need frame move info.
shouldEmitMoves = MMI->hasDebugInfo() ||
!Asm->MF->getFunction()->doesNotThrow() || UnwindTablesMandatory;
if (shouldEmitMoves || shouldEmitTable)
// Assumes in correct section after the entry point.
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_begin",
Asm->getFunctionNumber()));
shouldEmitTableModule |= shouldEmitTable;
if (shouldEmitMoves || shouldEmitTable)
Asm->OutStreamer.EmitCFIStartProc();
if (!shouldEmitTable)
return;
const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
// Provide LSDA information.
unsigned LSDAEncoding = TLOF.getLSDAEncoding();
if (LSDAEncoding != dwarf::DW_EH_PE_omit)
Asm->OutStreamer.EmitCFILsda(Asm->GetTempSymbol("exception",
Asm->getFunctionNumber()),
LSDAEncoding);
// Indicate personality routine, if any.
unsigned PerEncoding = TLOF.getPersonalityEncoding();
const Function *Per = MMI->getPersonalities()[MMI->getPersonalityIndex()];
if (PerEncoding == dwarf::DW_EH_PE_omit || !Per)
return;
const MCSymbol *Sym;
switch (PerEncoding & 0x70) {
default:
report_fatal_error("We do not support this DWARF encoding yet!");
case dwarf::DW_EH_PE_absptr: {
Sym = Asm->Mang->getSymbol(Per);
break;
}
case dwarf::DW_EH_PE_pcrel: {
Sym = Asm->GetTempSymbol("personality",
MMI->getPersonalityIndex());
break;
}
}
Asm->OutStreamer.EmitCFIPersonality(Sym, PerEncoding);
}
/// EndFunction - Gather and emit post-function exception information.
///
void DwarfCFIException::EndFunction() {
if (!shouldEmitMoves && !shouldEmitTable) return;
if (shouldEmitMoves)
Asm->OutStreamer.EmitCFIEndProc();
Asm->OutStreamer.EmitLabel(Asm->GetTempSymbol("eh_func_end",
Asm->getFunctionNumber()));
// Map all labels and get rid of any dead landing pads.
MMI->TidyLandingPads();
if (shouldEmitTable)
EmitExceptionTable();
}
|
