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(int 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(unsigned 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: return "absptr";
67 case dwarf::DW_EH_PE_omit: return "omit";
68 case dwarf::DW_EH_PE_pcrel: return "pcrel";
69 case dwarf::DW_EH_PE_udata4: return "udata4";
70 case dwarf::DW_EH_PE_udata8: return "udata8";
71 case dwarf::DW_EH_PE_sdata4: return "sdata4";
72 case dwarf::DW_EH_PE_sdata8: return "sdata8";
73 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4: return "pcrel udata4";
74 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4: return "pcrel sdata4";
75 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8: return "pcrel udata8";
76 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8: return "pcrel sdata8";
77 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4:
78 return "indirect pcrel udata4";
79 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4:
80 return "indirect pcrel sdata4";
81 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8:
82 return "indirect pcrel udata8";
83 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8:
84 return "indirect pcrel sdata8";
87 return "<unknown encoding>";
91 /// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an
92 /// encoding. If verbose assembly output is enabled, we output comments
93 /// describing the encoding. Desc is an optional string saying what the
94 /// encoding is specifying (e.g. "LSDA").
95 void AsmPrinter::EmitEncodingByte(unsigned Val, const char *Desc) const {
98 OutStreamer.AddComment(Twine(Desc)+" Encoding = " +
99 Twine(DecodeDWARFEncoding(Val)));
101 OutStreamer.AddComment(Twine("Encoding = ") +
102 DecodeDWARFEncoding(Val));
105 OutStreamer.EmitIntValue(Val, 1);
108 /// GetSizeOfEncodedValue - Return the size of the encoding in bytes.
109 unsigned AsmPrinter::GetSizeOfEncodedValue(unsigned Encoding) const {
110 if (Encoding == dwarf::DW_EH_PE_omit)
113 switch (Encoding & 0x07) {
114 default: llvm_unreachable("Invalid encoded value.");
115 case dwarf::DW_EH_PE_absptr: return TM.getDataLayout()->getPointerSize();
116 case dwarf::DW_EH_PE_udata2: return 2;
117 case dwarf::DW_EH_PE_udata4: return 4;
118 case dwarf::DW_EH_PE_udata8: return 8;
122 void AsmPrinter::EmitTTypeReference(const GlobalValue *GV,
123 unsigned Encoding) const {
125 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
128 TLOF.getTTypeGlobalReference(GV, Mang, MMI, Encoding, OutStreamer);
129 OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding));
131 OutStreamer.EmitIntValue(0, GetSizeOfEncodedValue(Encoding));
134 /// EmitSectionOffset - Emit the 4-byte offset of Label from the start of its
135 /// section. This can be done with a special directive if the target supports
136 /// it (e.g. cygwin) or by emitting it as an offset from a label at the start
139 /// SectionLabel is a temporary label emitted at the start of the section that
141 void AsmPrinter::EmitSectionOffset(const MCSymbol *Label,
142 const MCSymbol *SectionLabel) const {
143 // On COFF targets, we have to emit the special .secrel32 directive.
144 if (MAI->needsDwarfSectionOffsetDirective()) {
145 OutStreamer.EmitCOFFSecRel32(Label);
149 // Get the section that we're referring to, based on SectionLabel.
150 const MCSection &Section = SectionLabel->getSection();
152 // If Label has already been emitted, verify that it is in the same section as
153 // section label for sanity.
154 assert((!Label->isInSection() || &Label->getSection() == &Section) &&
155 "Section offset using wrong section base for label");
157 // If the section in question will end up with an address of 0 anyway, we can
158 // just emit an absolute reference to save a relocation.
159 if (Section.isBaseAddressKnownZero()) {
160 OutStreamer.EmitSymbolValue(Label, 4);
164 // Otherwise, emit it as a label difference from the start of the section.
165 EmitLabelDifference(Label, SectionLabel, 4);
168 //===----------------------------------------------------------------------===//
169 // Dwarf Lowering Routines
170 //===----------------------------------------------------------------------===//
172 void AsmPrinter::emitCFIInstruction(const MCCFIInstruction &Inst) const {
173 switch (Inst.getOperation()) {
175 llvm_unreachable("Unexpected instruction");
176 case MCCFIInstruction::OpDefCfaOffset:
177 OutStreamer.EmitCFIDefCfaOffset(Inst.getOffset());
179 case MCCFIInstruction::OpDefCfa:
180 OutStreamer.EmitCFIDefCfa(Inst.getRegister(), Inst.getOffset());
182 case MCCFIInstruction::OpDefCfaRegister:
183 OutStreamer.EmitCFIDefCfaRegister(Inst.getRegister());
185 case MCCFIInstruction::OpOffset:
186 OutStreamer.EmitCFIOffset(Inst.getRegister(), Inst.getOffset());