1
//===-- AsmPrinterDwarf.cpp - AsmPrinter Dwarf Support --------------------===//
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 implements the Dwarf emissions parts of AsmPrinter.
12
//===----------------------------------------------------------------------===//
14
#include "ByteStreamer.h"
15
#include "DwarfDebug.h"
16
#include "DwarfExpression.h"
17
#include "llvm/ADT/Twine.h"
18
#include "llvm/CodeGen/AsmPrinter.h"
19
#include "llvm/CodeGen/DIE.h"
20
#include "llvm/CodeGen/MachineFunction.h"
21
#include "llvm/CodeGen/MachineModuleInfo.h"
22
#include "llvm/IR/DataLayout.h"
23
#include "llvm/MC/MCAsmInfo.h"
24
#include "llvm/MC/MCRegisterInfo.h"
25
#include "llvm/MC/MCSection.h"
26
#include "llvm/MC/MCStreamer.h"
27
#include "llvm/MC/MCSymbol.h"
28
#include "llvm/MC/MachineLocation.h"
29
#include "llvm/Support/Dwarf.h"
30
#include "llvm/Support/ErrorHandling.h"
31
#include "llvm/Target/TargetLoweringObjectFile.h"
32
#include "llvm/Target/TargetMachine.h"
33
#include "llvm/Target/TargetSubtargetInfo.h"
36
#define DEBUG_TYPE "asm-printer"
38
//===----------------------------------------------------------------------===//
39
// Dwarf Emission Helper Routines
40
//===----------------------------------------------------------------------===//
42
/// EmitSLEB128 - emit the specified signed leb128 value.
43
void AsmPrinter::EmitSLEB128(int64_t Value, const char *Desc) const {
44
if (isVerbose() && Desc)
45
OutStreamer->AddComment(Desc);
47
OutStreamer->EmitSLEB128IntValue(Value);
50
/// EmitULEB128 - emit the specified signed leb128 value.
51
void AsmPrinter::EmitULEB128(uint64_t Value, const char *Desc,
52
unsigned PadTo) const {
53
if (isVerbose() && Desc)
54
OutStreamer->AddComment(Desc);
56
OutStreamer->EmitULEB128IntValue(Value, PadTo);
59
/// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value.
60
void AsmPrinter::EmitCFAByte(unsigned Val) const {
62
if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset + 64)
63
OutStreamer->AddComment("DW_CFA_offset + Reg (" +
64
Twine(Val - dwarf::DW_CFA_offset) + ")");
66
OutStreamer->AddComment(dwarf::CallFrameString(Val));
68
OutStreamer->EmitIntValue(Val, 1);
71
static const char *DecodeDWARFEncoding(unsigned Encoding) {
73
case dwarf::DW_EH_PE_absptr:
75
case dwarf::DW_EH_PE_omit:
77
case dwarf::DW_EH_PE_pcrel:
79
case dwarf::DW_EH_PE_udata4:
81
case dwarf::DW_EH_PE_udata8:
83
case dwarf::DW_EH_PE_sdata4:
85
case dwarf::DW_EH_PE_sdata8:
87
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
88
return "pcrel udata4";
89
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
90
return "pcrel sdata4";
91
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
92
return "pcrel udata8";
93
case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
94
return "pcrel sdata8";
95
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4
97
return "indirect pcrel udata4";
98
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
100
return "indirect pcrel sdata4";
101
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8
103
return "indirect pcrel udata8";
104
case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8
106
return "indirect pcrel sdata8";
109
return "<unknown encoding>";
112
/// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an
113
/// encoding. If verbose assembly output is enabled, we output comments
114
/// describing the encoding. Desc is an optional string saying what the
115
/// encoding is specifying (e.g. "LSDA").
116
void AsmPrinter::EmitEncodingByte(unsigned Val, const char *Desc) const {
119
OutStreamer->AddComment(Twine(Desc) + " Encoding = " +
120
Twine(DecodeDWARFEncoding(Val)));
122
OutStreamer->AddComment(Twine("Encoding = ") + DecodeDWARFEncoding(Val));
125
OutStreamer->EmitIntValue(Val, 1);
128
/// GetSizeOfEncodedValue - Return the size of the encoding in bytes.
129
unsigned AsmPrinter::GetSizeOfEncodedValue(unsigned Encoding) const {
130
if (Encoding == dwarf::DW_EH_PE_omit)
133
switch (Encoding & 0x07) {
135
llvm_unreachable("Invalid encoded value.");
136
case dwarf::DW_EH_PE_absptr:
137
return TM.getDataLayout()->getPointerSize();
138
case dwarf::DW_EH_PE_udata2:
140
case dwarf::DW_EH_PE_udata4:
142
case dwarf::DW_EH_PE_udata8:
147
void AsmPrinter::EmitTTypeReference(const GlobalValue *GV,
148
unsigned Encoding) const {
150
const TargetLoweringObjectFile &TLOF = getObjFileLowering();
153
TLOF.getTTypeGlobalReference(GV, Encoding, *Mang, TM, MMI,
155
OutStreamer->EmitValue(Exp, GetSizeOfEncodedValue(Encoding));
157
OutStreamer->EmitIntValue(0, GetSizeOfEncodedValue(Encoding));
160
void AsmPrinter::emitDwarfSymbolReference(const MCSymbol *Label,
161
bool ForceOffset) const {
163
// On COFF targets, we have to emit the special .secrel32 directive.
164
if (MAI->needsDwarfSectionOffsetDirective()) {
165
OutStreamer->EmitCOFFSecRel32(Label);
169
// If the format uses relocations with dwarf, refer to the symbol directly.
170
if (MAI->doesDwarfUseRelocationsAcrossSections()) {
171
OutStreamer->EmitSymbolValue(Label, 4);
176
// Otherwise, emit it as a label difference from the start of the section.
177
EmitLabelDifference(Label, Label->getSection().getBeginSymbol(), 4);
180
void AsmPrinter::emitDwarfStringOffset(DwarfStringPoolEntryRef S) const {
181
if (MAI->doesDwarfUseRelocationsAcrossSections()) {
182
emitDwarfSymbolReference(S.getSymbol());
186
// Just emit the offset directly; no need for symbol math.
187
EmitInt32(S.getOffset());
190
/// EmitDwarfRegOp - Emit dwarf register operation.
191
void AsmPrinter::EmitDwarfRegOp(ByteStreamer &Streamer,
192
const MachineLocation &MLoc) const {
193
DebugLocDwarfExpression Expr(*MF->getSubtarget().getRegisterInfo(),
194
getDwarfDebug()->getDwarfVersion(), Streamer);
195
const MCRegisterInfo *MRI = MMI->getContext().getRegisterInfo();
196
int Reg = MRI->getDwarfRegNum(MLoc.getReg(), false);
198
// We assume that pointers are always in an addressable register.
199
if (MLoc.isIndirect())
200
// FIXME: We have no reasonable way of handling errors in here. The
201
// caller might be in the middle of a dwarf expression. We should
202
// probably assert that Reg >= 0 once debug info generation is more
204
return Expr.EmitOp(dwarf::DW_OP_nop,
205
"nop (could not find a dwarf register number)");
207
// Attempt to find a valid super- or sub-register.
208
if (!Expr.AddMachineRegPiece(MLoc.getReg()))
209
Expr.EmitOp(dwarf::DW_OP_nop,
210
"nop (could not find a dwarf register number)");
214
if (MLoc.isIndirect())
215
Expr.AddRegIndirect(Reg, MLoc.getOffset());
220
//===----------------------------------------------------------------------===//
221
// Dwarf Lowering Routines
222
//===----------------------------------------------------------------------===//
224
void AsmPrinter::emitCFIInstruction(const MCCFIInstruction &Inst) const {
225
switch (Inst.getOperation()) {
227
llvm_unreachable("Unexpected instruction");
228
case MCCFIInstruction::OpDefCfaOffset:
229
OutStreamer->EmitCFIDefCfaOffset(Inst.getOffset());
231
case MCCFIInstruction::OpDefCfa:
232
OutStreamer->EmitCFIDefCfa(Inst.getRegister(), Inst.getOffset());
234
case MCCFIInstruction::OpDefCfaRegister:
235
OutStreamer->EmitCFIDefCfaRegister(Inst.getRegister());
237
case MCCFIInstruction::OpOffset:
238
OutStreamer->EmitCFIOffset(Inst.getRegister(), Inst.getOffset());
240
case MCCFIInstruction::OpRegister:
241
OutStreamer->EmitCFIRegister(Inst.getRegister(), Inst.getRegister2());
243
case MCCFIInstruction::OpWindowSave:
244
OutStreamer->EmitCFIWindowSave();
246
case MCCFIInstruction::OpSameValue:
247
OutStreamer->EmitCFISameValue(Inst.getRegister());
252
void AsmPrinter::emitDwarfDIE(const DIE &Die) const {
253
// Emit the code (index) for the abbreviation.
255
OutStreamer->AddComment("Abbrev [" + Twine(Die.getAbbrevNumber()) + "] 0x" +
256
Twine::utohexstr(Die.getOffset()) + ":0x" +
257
Twine::utohexstr(Die.getSize()) + " " +
258
dwarf::TagString(Die.getTag()));
259
EmitULEB128(Die.getAbbrevNumber());
261
// Emit the DIE attribute values.
262
for (const auto &V : Die.values()) {
263
dwarf::Attribute Attr = V.getAttribute();
264
assert(V.getForm() && "Too many attributes for DIE (check abbreviation)");
267
OutStreamer->AddComment(dwarf::AttributeString(Attr));
268
if (Attr == dwarf::DW_AT_accessibility)
269
OutStreamer->AddComment(
270
dwarf::AccessibilityString(V.getDIEInteger().getValue()));
273
// Emit an attribute using the defined form.
277
// Emit the DIE children if any.
278
if (Die.hasChildren()) {
279
for (auto &Child : Die.children())
282
OutStreamer->AddComment("End Of Children Mark");
288
AsmPrinter::emitDwarfAbbrevs(const std::vector<DIEAbbrev *>& Abbrevs) const {
289
// For each abbrevation.
290
for (const DIEAbbrev *Abbrev : Abbrevs) {
291
// Emit the abbrevations code (base 1 index.)
292
EmitULEB128(Abbrev->getNumber(), "Abbreviation Code");
294
// Emit the abbreviations data.
298
// Mark end of abbreviations.
299
EmitULEB128(0, "EOM(3)");