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 #define DEBUG_TYPE "asm-printer"
15 #include "llvm/CodeGen/AsmPrinter.h"
16 #include "llvm/ADT/Twine.h"
17 #include "llvm/IR/DataLayout.h"
18 #include "llvm/MC/MCAsmInfo.h"
19 #include "llvm/MC/MCSection.h"
20 #include "llvm/MC/MCStreamer.h"
21 #include "llvm/MC/MCSymbol.h"
22 #include "llvm/MC/MachineLocation.h"
23 #include "llvm/Support/Dwarf.h"
24 #include "llvm/Support/ErrorHandling.h"
25 #include "llvm/Target/TargetFrameLowering.h"
26 #include "llvm/Target/TargetLoweringObjectFile.h"
27 #include "llvm/Target/TargetMachine.h"
28 #include "llvm/Target/TargetRegisterInfo.h"
31 //===----------------------------------------------------------------------===//
32 // Dwarf Emission Helper Routines
33 //===----------------------------------------------------------------------===//
35 /// EmitSLEB128 - emit the specified signed leb128 value.
36 void AsmPrinter::EmitSLEB128(int64_t Value, const char *Desc) const {
37 if (isVerbose() && Desc)
38 OutStreamer.AddComment(Desc);
40 OutStreamer.EmitSLEB128IntValue(Value);
43 /// EmitULEB128 - emit the specified signed leb128 value.
44 void AsmPrinter::EmitULEB128(uint64_t Value, const char *Desc,
45 unsigned PadTo) const {
46 if (isVerbose() && Desc)
47 OutStreamer.AddComment(Desc);
49 OutStreamer.EmitULEB128IntValue(Value, PadTo);
52 /// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value.
53 void AsmPrinter::EmitCFAByte(unsigned Val) const {
55 if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset + 64)
56 OutStreamer.AddComment("DW_CFA_offset + Reg (" +
57 Twine(Val - dwarf::DW_CFA_offset) + ")");
59 OutStreamer.AddComment(dwarf::CallFrameString(Val));
61 OutStreamer.EmitIntValue(Val, 1);
64 static const char *DecodeDWARFEncoding(unsigned Encoding) {
66 case dwarf::DW_EH_PE_absptr:
68 case dwarf::DW_EH_PE_omit:
70 case dwarf::DW_EH_PE_pcrel:
72 case dwarf::DW_EH_PE_udata4:
74 case dwarf::DW_EH_PE_udata8:
76 case dwarf::DW_EH_PE_sdata4:
78 case dwarf::DW_EH_PE_sdata8:
80 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4:
81 return "pcrel udata4";
82 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4:
83 return "pcrel sdata4";
84 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8:
85 return "pcrel udata8";
86 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8:
87 return "pcrel sdata8";
88 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4
90 return "indirect pcrel udata4";
91 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
93 return "indirect pcrel sdata4";
94 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8
96 return "indirect pcrel udata8";
97 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8
99 return "indirect pcrel sdata8";
102 return "<unknown encoding>";
105 /// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an
106 /// encoding. If verbose assembly output is enabled, we output comments
107 /// describing the encoding. Desc is an optional string saying what the
108 /// encoding is specifying (e.g. "LSDA").
109 void AsmPrinter::EmitEncodingByte(unsigned Val, const char *Desc) const {
112 OutStreamer.AddComment(Twine(Desc) + " Encoding = " +
113 Twine(DecodeDWARFEncoding(Val)));
115 OutStreamer.AddComment(Twine("Encoding = ") + DecodeDWARFEncoding(Val));
118 OutStreamer.EmitIntValue(Val, 1);
121 /// GetSizeOfEncodedValue - Return the size of the encoding in bytes.
122 unsigned AsmPrinter::GetSizeOfEncodedValue(unsigned Encoding) const {
123 if (Encoding == dwarf::DW_EH_PE_omit)
126 switch (Encoding & 0x07) {
128 llvm_unreachable("Invalid encoded value.");
129 case dwarf::DW_EH_PE_absptr:
130 return TM.getDataLayout()->getPointerSize();
131 case dwarf::DW_EH_PE_udata2:
133 case dwarf::DW_EH_PE_udata4:
135 case dwarf::DW_EH_PE_udata8:
140 void AsmPrinter::EmitTTypeReference(const GlobalValue *GV,
141 unsigned Encoding) const {
143 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
146 TLOF.getTTypeGlobalReference(GV, Encoding, *Mang, MMI, OutStreamer);
147 OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding));
149 OutStreamer.EmitIntValue(0, GetSizeOfEncodedValue(Encoding));
152 /// EmitSectionOffset - Emit the 4-byte offset of Label from the start of its
153 /// section. This can be done with a special directive if the target supports
154 /// it (e.g. cygwin) or by emitting it as an offset from a label at the start
157 /// SectionLabel is a temporary label emitted at the start of the section that
159 void AsmPrinter::EmitSectionOffset(const MCSymbol *Label,
160 const MCSymbol *SectionLabel) const {
161 // On COFF targets, we have to emit the special .secrel32 directive.
162 if (MAI->needsDwarfSectionOffsetDirective()) {
163 OutStreamer.EmitCOFFSecRel32(Label);
167 // Get the section that we're referring to, based on SectionLabel.
168 const MCSection &Section = SectionLabel->getSection();
170 // If Label has already been emitted, verify that it is in the same section as
171 // section label for sanity.
172 assert((!Label->isInSection() || &Label->getSection() == &Section) &&
173 "Section offset using wrong section base for label");
175 // If the section in question will end up with an address of 0 anyway, we can
176 // just emit an absolute reference to save a relocation.
177 if (Section.isBaseAddressKnownZero()) {
178 OutStreamer.EmitSymbolValue(Label, 4);
182 // Otherwise, emit it as a label difference from the start of the section.
183 EmitLabelDifference(Label, SectionLabel, 4);
186 //===----------------------------------------------------------------------===//
187 // Dwarf Lowering Routines
188 //===----------------------------------------------------------------------===//
190 void AsmPrinter::emitCFIInstruction(const MCCFIInstruction &Inst) const {
191 switch (Inst.getOperation()) {
193 llvm_unreachable("Unexpected instruction");
194 case MCCFIInstruction::OpDefCfaOffset:
195 OutStreamer.EmitCFIDefCfaOffset(Inst.getOffset());
197 case MCCFIInstruction::OpDefCfa:
198 OutStreamer.EmitCFIDefCfa(Inst.getRegister(), Inst.getOffset());
200 case MCCFIInstruction::OpDefCfaRegister:
201 OutStreamer.EmitCFIDefCfaRegister(Inst.getRegister());
203 case MCCFIInstruction::OpOffset:
204 OutStreamer.EmitCFIOffset(Inst.getRegister(), Inst.getOffset());
206 case MCCFIInstruction::OpRegister:
207 OutStreamer.EmitCFIRegister(Inst.getRegister(), Inst.getRegister2());
209 case MCCFIInstruction::OpWindowSave:
210 OutStreamer.EmitCFIWindowSave();