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/MC/MachineLocation.h"
17 #include "llvm/MC/MCAsmInfo.h"
18 #include "llvm/MC/MCSection.h"
19 #include "llvm/MC/MCStreamer.h"
20 #include "llvm/MC/MCSymbol.h"
21 #include "llvm/DataLayout.h"
22 #include "llvm/Target/TargetFrameLowering.h"
23 #include "llvm/Target/TargetLoweringObjectFile.h"
24 #include "llvm/Target/TargetMachine.h"
25 #include "llvm/Target/TargetRegisterInfo.h"
26 #include "llvm/ADT/Twine.h"
27 #include "llvm/Support/Dwarf.h"
28 #include "llvm/Support/ErrorHandling.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, 0/*addrspace*/, 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, 0/*addrspace*/);
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, 0/*addrspace*/);
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, unsigned Encoding)const{
123 const TargetLoweringObjectFile &TLOF = getObjFileLowering();
126 TLOF.getTTypeGlobalReference(GV, Mang, MMI, Encoding, OutStreamer);
127 OutStreamer.EmitValue(Exp, GetSizeOfEncodedValue(Encoding), /*addrspace*/0);
130 /// EmitSectionOffset - Emit the 4-byte offset of Label from the start of its
131 /// section. This can be done with a special directive if the target supports
132 /// it (e.g. cygwin) or by emitting it as an offset from a label at the start
135 /// SectionLabel is a temporary label emitted at the start of the section that
137 void AsmPrinter::EmitSectionOffset(const MCSymbol *Label,
138 const MCSymbol *SectionLabel) const {
139 // On COFF targets, we have to emit the special .secrel32 directive.
140 if (MAI->getDwarfSectionOffsetDirective()) {
141 OutStreamer.EmitCOFFSecRel32(Label);
145 // Get the section that we're referring to, based on SectionLabel.
146 const MCSection &Section = SectionLabel->getSection();
148 // If Label has already been emitted, verify that it is in the same section as
149 // section label for sanity.
150 assert((!Label->isInSection() || &Label->getSection() == &Section) &&
151 "Section offset using wrong section base for label");
153 // If the section in question will end up with an address of 0 anyway, we can
154 // just emit an absolute reference to save a relocation.
155 if (Section.isBaseAddressKnownZero()) {
156 OutStreamer.EmitSymbolValue(Label, 4, 0/*AddrSpace*/);
160 // Otherwise, emit it as a label difference from the start of the section.
161 EmitLabelDifference(Label, SectionLabel, 4);
164 //===----------------------------------------------------------------------===//
165 // Dwarf Lowering Routines
166 //===----------------------------------------------------------------------===//
168 /// EmitCFIFrameMove - Emit a frame instruction.
169 void AsmPrinter::EmitCFIFrameMove(const MachineMove &Move) const {
170 const TargetRegisterInfo *RI = TM.getRegisterInfo();
172 const MachineLocation &Dst = Move.getDestination();
173 const MachineLocation &Src = Move.getSource();
176 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
177 if (Src.getReg() == MachineLocation::VirtualFP) {
178 OutStreamer.EmitCFIDefCfaOffset(-Src.getOffset());
181 OutStreamer.EmitCFIDefCfa(RI->getDwarfRegNum(Src.getReg(), true),
184 } else if (Src.isReg() && Src.getReg() == MachineLocation::VirtualFP) {
185 assert(Dst.isReg() && "Machine move not supported yet.");
186 OutStreamer.EmitCFIDefCfaRegister(RI->getDwarfRegNum(Dst.getReg(), true));
188 assert(!Dst.isReg() && "Machine move not supported yet.");
189 OutStreamer.EmitCFIOffset(RI->getDwarfRegNum(Src.getReg(), true),