1 //===--- lib/CodeGen/DwarfPrinter.cpp - Dwarf Printer ---------------------===//
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 // Emit general DWARF directives.
12 //===----------------------------------------------------------------------===//
14 #include "DwarfPrinter.h"
15 #include "llvm/Module.h"
16 #include "llvm/CodeGen/AsmPrinter.h"
17 #include "llvm/CodeGen/MachineFrameInfo.h"
18 #include "llvm/CodeGen/MachineFunction.h"
19 #include "llvm/CodeGen/MachineModuleInfo.h"
20 #include "llvm/MC/MCAsmInfo.h"
21 #include "llvm/MC/MCContext.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCStreamer.h"
24 #include "llvm/MC/MCSymbol.h"
25 #include "llvm/Target/TargetData.h"
26 #include "llvm/Target/TargetFrameInfo.h"
27 #include "llvm/Target/TargetLoweringObjectFile.h"
28 #include "llvm/Target/TargetRegisterInfo.h"
29 #include "llvm/Support/Dwarf.h"
30 #include "llvm/Support/ErrorHandling.h"
31 #include "llvm/ADT/SmallString.h"
34 DwarfPrinter::DwarfPrinter(AsmPrinter *A)
35 : Asm(A), MAI(A->MAI), TD(Asm->TM.getTargetData()),
36 RI(Asm->TM.getRegisterInfo()), M(NULL), MF(NULL), MMI(NULL),
40 /// getDWLabel - Return the MCSymbol corresponding to the assembler temporary
41 /// label with the specified stem and unique ID.
42 MCSymbol *DwarfPrinter::getDWLabel(const char *Name, unsigned ID) const {
43 // FIXME: REMOVE this. However, there is stuff in EH that passes counters in
44 // here that can be zero.
46 //assert(ID && "Should use getTempLabel if no ID");
47 if (ID == 0) return getTempLabel(Name);
48 return Asm->OutContext.GetOrCreateSymbol
49 (Twine(MAI->getPrivateGlobalPrefix()) + Twine(Name) + Twine(ID));
52 /// getTempLabel - Return the MCSymbol corresponding to the assembler temporary
53 /// label with the specified name.
54 MCSymbol *DwarfPrinter::getTempLabel(const char *Name) const {
55 return Asm->OutContext.GetOrCreateSymbol
56 (Twine(MAI->getPrivateGlobalPrefix()) + Name);
60 /// SizeOfEncodedValue - Return the size of the encoding in bytes.
61 unsigned DwarfPrinter::SizeOfEncodedValue(unsigned Encoding) const {
62 if (Encoding == dwarf::DW_EH_PE_omit)
65 switch (Encoding & 0x07) {
66 case dwarf::DW_EH_PE_absptr:
67 return TD->getPointerSize();
68 case dwarf::DW_EH_PE_udata2:
70 case dwarf::DW_EH_PE_udata4:
72 case dwarf::DW_EH_PE_udata8:
76 assert(0 && "Invalid encoded value.");
80 static const char *DecodeDWARFEncoding(unsigned Encoding) {
82 case dwarf::DW_EH_PE_absptr: return "absptr";
83 case dwarf::DW_EH_PE_omit: return "omit";
84 case dwarf::DW_EH_PE_pcrel: return "pcrel";
85 case dwarf::DW_EH_PE_udata4: return "udata4";
86 case dwarf::DW_EH_PE_udata8: return "udata8";
87 case dwarf::DW_EH_PE_sdata4: return "sdata4";
88 case dwarf::DW_EH_PE_sdata8: return "sdata8";
89 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata4: return "pcrel udata4";
90 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4: return "pcrel sdata4";
91 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8: return "pcrel udata8";
92 case dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8: return "pcrel sdata8";
93 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata4:
94 return "indirect pcrel udata4";
95 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata4:
96 return "indirect pcrel sdata4";
97 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_udata8:
98 return "indirect pcrel udata8";
99 case dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |dwarf::DW_EH_PE_sdata8:
100 return "indirect pcrel sdata8";
103 return "<unknown encoding>";
106 /// EmitEncodingByte - Emit a .byte 42 directive that corresponds to an
107 /// encoding. If verbose assembly output is enabled, we output comments
108 /// describing the encoding. Desc is an optional string saying what the
109 /// encoding is specifying (e.g. "LSDA").
110 void DwarfPrinter::EmitEncodingByte(unsigned Val, const char *Desc) {
111 if (Asm->VerboseAsm) {
113 Asm->OutStreamer.AddComment(Twine(Desc)+" Encoding = " +
114 Twine(DecodeDWARFEncoding(Val)));
116 Asm->OutStreamer.AddComment(Twine("Encoding = ") +
117 DecodeDWARFEncoding(Val));
120 Asm->OutStreamer.EmitIntValue(Val, 1, 0/*addrspace*/);
123 /// EmitCFAByte - Emit a .byte 42 directive for a DW_CFA_xxx value.
124 void DwarfPrinter::EmitCFAByte(unsigned Val) {
125 if (Asm->VerboseAsm) {
126 if (Val >= dwarf::DW_CFA_offset && Val < dwarf::DW_CFA_offset+64)
127 Asm->OutStreamer.AddComment("DW_CFA_offset + Reg (" +
128 Twine(Val-dwarf::DW_CFA_offset) + ")");
130 Asm->OutStreamer.AddComment(dwarf::CallFrameString(Val));
132 Asm->OutStreamer.EmitIntValue(Val, 1, 0/*addrspace*/);
135 /// EmitSLEB128 - emit the specified signed leb128 value.
136 void DwarfPrinter::EmitSLEB128(int Value, const char *Desc) const {
137 if (Asm->VerboseAsm && Desc)
138 Asm->OutStreamer.AddComment(Desc);
140 if (MAI->hasLEB128()) {
142 Asm->OutStreamer.EmitRawText("\t.sleb128\t" + Twine(Value));
146 // If we don't have .sleb128, emit as .bytes.
147 int Sign = Value >> (8 * sizeof(Value) - 1);
151 unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
153 IsMore = Value != Sign || ((Byte ^ Sign) & 0x40) != 0;
154 if (IsMore) Byte |= 0x80;
155 Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
159 /// EmitULEB128 - emit the specified signed leb128 value.
160 void DwarfPrinter::EmitULEB128(unsigned Value, const char *Desc,
161 unsigned PadTo) const {
162 if (Asm->VerboseAsm && Desc)
163 Asm->OutStreamer.AddComment(Desc);
165 if (MAI->hasLEB128() && PadTo == 0) {
167 Asm->OutStreamer.EmitRawText("\t.uleb128\t" + Twine(Value));
171 // If we don't have .uleb128 or we want to emit padding, emit as .bytes.
173 unsigned char Byte = static_cast<unsigned char>(Value & 0x7f);
175 if (Value || PadTo != 0) Byte |= 0x80;
176 Asm->OutStreamer.EmitIntValue(Byte, 1, /*addrspace*/0);
181 Asm->OutStreamer.EmitFill(PadTo - 1, 0x80/*fillval*/, 0/*addrspace*/);
182 Asm->OutStreamer.EmitFill(1, 0/*fillval*/, 0/*addrspace*/);
187 void DwarfPrinter::EmitReference(const MCSymbol *Sym, unsigned Encoding) const {
188 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
190 const MCExpr *Exp = TLOF.getExprForDwarfReference(Sym, Asm->Mang,
193 Asm->OutStreamer.EmitValue(Exp, SizeOfEncodedValue(Encoding), /*addrspace*/0);
196 void DwarfPrinter::EmitReference(const GlobalValue *GV, unsigned Encoding)const{
197 const TargetLoweringObjectFile &TLOF = Asm->getObjFileLowering();
200 TLOF.getExprForDwarfGlobalReference(GV, Asm->Mang, Asm->MMI, Encoding,
202 Asm->OutStreamer.EmitValue(Exp, SizeOfEncodedValue(Encoding), /*addrspace*/0);
205 /// EmitDifference - Emit the difference between two labels. If this assembler
206 /// supports .set, we emit a .set of a temporary and then use it in the .word.
207 void DwarfPrinter::EmitDifference(const MCSymbol *TagHi, const MCSymbol *TagLo,
209 unsigned Size = IsSmall ? 4 : TD->getPointerSize();
210 Asm->EmitLabelDifference(TagHi, TagLo, Size);
213 void DwarfPrinter::EmitSectionOffset(const MCSymbol *Label,
214 const MCSymbol *Section,
215 bool IsSmall, bool isEH) {
218 isAbsolute = MAI->isAbsoluteEHSectionOffsets();
220 isAbsolute = MAI->isAbsoluteDebugSectionOffsets();
223 return EmitDifference(Label, Section, IsSmall);
225 // On COFF targets, we have to emit the weird .secrel32 directive.
226 if (const char *SecOffDir = MAI->getDwarfSectionOffsetDirective()) {
228 Asm->OutStreamer.EmitRawText(SecOffDir + Twine(Label->getName()));
230 unsigned Size = IsSmall ? 4 : TD->getPointerSize();
231 Asm->OutStreamer.EmitSymbolValue(Label, Size, 0/*AddrSpace*/);
235 /// EmitFrameMoves - Emit frame instructions to describe the layout of the
237 void DwarfPrinter::EmitFrameMoves(MCSymbol *BaseLabel,
238 const std::vector<MachineMove> &Moves,
240 int stackGrowth = TD->getPointerSize();
241 if (Asm->TM.getFrameInfo()->getStackGrowthDirection() !=
242 TargetFrameInfo::StackGrowsUp)
245 for (unsigned i = 0, N = Moves.size(); i < N; ++i) {
246 const MachineMove &Move = Moves[i];
247 MCSymbol *Label = Move.getLabel();
248 // Throw out move if the label is invalid.
249 if (Label && !Label->isDefined()) continue; // Not emitted, in dead code.
251 const MachineLocation &Dst = Move.getDestination();
252 const MachineLocation &Src = Move.getSource();
254 // Advance row if new location.
255 if (BaseLabel && Label) {
256 MCSymbol *ThisSym = Label;
257 if (ThisSym != BaseLabel) {
258 EmitCFAByte(dwarf::DW_CFA_advance_loc4);
259 EmitDifference(ThisSym, BaseLabel, true);
265 if (Dst.isReg() && Dst.getReg() == MachineLocation::VirtualFP) {
267 if (Src.getReg() == MachineLocation::VirtualFP) {
268 EmitCFAByte(dwarf::DW_CFA_def_cfa_offset);
270 EmitCFAByte(dwarf::DW_CFA_def_cfa);
271 EmitULEB128(RI->getDwarfRegNum(Src.getReg(), isEH), "Register");
274 int Offset = -Src.getOffset();
275 EmitULEB128(Offset, "Offset");
277 llvm_unreachable("Machine move not supported yet.");
279 } else if (Src.isReg() &&
280 Src.getReg() == MachineLocation::VirtualFP) {
282 EmitCFAByte(dwarf::DW_CFA_def_cfa_register);
283 EmitULEB128(RI->getDwarfRegNum(Dst.getReg(), isEH), "Register");
285 llvm_unreachable("Machine move not supported yet.");
288 unsigned Reg = RI->getDwarfRegNum(Src.getReg(), isEH);
289 int Offset = Dst.getOffset() / stackGrowth;
292 EmitCFAByte(dwarf::DW_CFA_offset_extended_sf);
293 EmitULEB128(Reg, "Reg");
294 EmitSLEB128(Offset, "Offset");
295 } else if (Reg < 64) {
296 EmitCFAByte(dwarf::DW_CFA_offset + Reg);
297 EmitULEB128(Offset, "Offset");
299 EmitCFAByte(dwarf::DW_CFA_offset_extended);
300 EmitULEB128(Reg, "Reg");
301 EmitULEB128(Offset, "Offset");