1 //===-- DWARFExpression.cpp -----------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 #include "llvm/DebugInfo/DWARF/DWARFExpression.h"
10 #include "llvm/ADT/SmallString.h"
11 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
12 #include "llvm/Support/Format.h"
13 #include <cassert>
14 #include <cstdint>
15 #include <vector>
16
17 using namespace llvm;
18 using namespace dwarf;
19
20 namespace llvm {
21
22 typedef DWARFExpression::Operation Op;
23 typedef Op::Description Desc;
24
getOpDescriptions()25 static std::vector<Desc> getOpDescriptions() {
26 std::vector<Desc> Descriptions;
27 Descriptions.resize(0xff);
28 Descriptions[DW_OP_addr] = Desc(Op::Dwarf2, Op::SizeAddr);
29 Descriptions[DW_OP_deref] = Desc(Op::Dwarf2);
30 Descriptions[DW_OP_const1u] = Desc(Op::Dwarf2, Op::Size1);
31 Descriptions[DW_OP_const1s] = Desc(Op::Dwarf2, Op::SignedSize1);
32 Descriptions[DW_OP_const2u] = Desc(Op::Dwarf2, Op::Size2);
33 Descriptions[DW_OP_const2s] = Desc(Op::Dwarf2, Op::SignedSize2);
34 Descriptions[DW_OP_const4u] = Desc(Op::Dwarf2, Op::Size4);
35 Descriptions[DW_OP_const4s] = Desc(Op::Dwarf2, Op::SignedSize4);
36 Descriptions[DW_OP_const8u] = Desc(Op::Dwarf2, Op::Size8);
37 Descriptions[DW_OP_const8s] = Desc(Op::Dwarf2, Op::SignedSize8);
38 Descriptions[DW_OP_constu] = Desc(Op::Dwarf2, Op::SizeLEB);
39 Descriptions[DW_OP_consts] = Desc(Op::Dwarf2, Op::SignedSizeLEB);
40 Descriptions[DW_OP_dup] = Desc(Op::Dwarf2);
41 Descriptions[DW_OP_drop] = Desc(Op::Dwarf2);
42 Descriptions[DW_OP_over] = Desc(Op::Dwarf2);
43 Descriptions[DW_OP_pick] = Desc(Op::Dwarf2, Op::Size1);
44 Descriptions[DW_OP_swap] = Desc(Op::Dwarf2);
45 Descriptions[DW_OP_rot] = Desc(Op::Dwarf2);
46 Descriptions[DW_OP_xderef] = Desc(Op::Dwarf2);
47 Descriptions[DW_OP_abs] = Desc(Op::Dwarf2);
48 Descriptions[DW_OP_and] = Desc(Op::Dwarf2);
49 Descriptions[DW_OP_div] = Desc(Op::Dwarf2);
50 Descriptions[DW_OP_minus] = Desc(Op::Dwarf2);
51 Descriptions[DW_OP_mod] = Desc(Op::Dwarf2);
52 Descriptions[DW_OP_mul] = Desc(Op::Dwarf2);
53 Descriptions[DW_OP_neg] = Desc(Op::Dwarf2);
54 Descriptions[DW_OP_not] = Desc(Op::Dwarf2);
55 Descriptions[DW_OP_or] = Desc(Op::Dwarf2);
56 Descriptions[DW_OP_plus] = Desc(Op::Dwarf2);
57 Descriptions[DW_OP_plus_uconst] = Desc(Op::Dwarf2, Op::SizeLEB);
58 Descriptions[DW_OP_shl] = Desc(Op::Dwarf2);
59 Descriptions[DW_OP_shr] = Desc(Op::Dwarf2);
60 Descriptions[DW_OP_shra] = Desc(Op::Dwarf2);
61 Descriptions[DW_OP_xor] = Desc(Op::Dwarf2);
62 Descriptions[DW_OP_skip] = Desc(Op::Dwarf2, Op::SignedSize2);
63 Descriptions[DW_OP_bra] = Desc(Op::Dwarf2, Op::SignedSize2);
64 Descriptions[DW_OP_eq] = Desc(Op::Dwarf2);
65 Descriptions[DW_OP_ge] = Desc(Op::Dwarf2);
66 Descriptions[DW_OP_gt] = Desc(Op::Dwarf2);
67 Descriptions[DW_OP_le] = Desc(Op::Dwarf2);
68 Descriptions[DW_OP_lt] = Desc(Op::Dwarf2);
69 Descriptions[DW_OP_ne] = Desc(Op::Dwarf2);
70 for (uint16_t LA = DW_OP_lit0; LA <= DW_OP_lit31; ++LA)
71 Descriptions[LA] = Desc(Op::Dwarf2);
72 for (uint16_t LA = DW_OP_reg0; LA <= DW_OP_reg31; ++LA)
73 Descriptions[LA] = Desc(Op::Dwarf2);
74 for (uint16_t LA = DW_OP_breg0; LA <= DW_OP_breg31; ++LA)
75 Descriptions[LA] = Desc(Op::Dwarf2, Op::SignedSizeLEB);
76 Descriptions[DW_OP_regx] = Desc(Op::Dwarf2, Op::SizeLEB);
77 Descriptions[DW_OP_fbreg] = Desc(Op::Dwarf2, Op::SignedSizeLEB);
78 Descriptions[DW_OP_bregx] = Desc(Op::Dwarf2, Op::SizeLEB, Op::SignedSizeLEB);
79 Descriptions[DW_OP_piece] = Desc(Op::Dwarf2, Op::SizeLEB);
80 Descriptions[DW_OP_deref_size] = Desc(Op::Dwarf2, Op::Size1);
81 Descriptions[DW_OP_xderef_size] = Desc(Op::Dwarf2, Op::Size1);
82 Descriptions[DW_OP_nop] = Desc(Op::Dwarf2);
83 Descriptions[DW_OP_push_object_address] = Desc(Op::Dwarf3);
84 Descriptions[DW_OP_call2] = Desc(Op::Dwarf3, Op::Size2);
85 Descriptions[DW_OP_call4] = Desc(Op::Dwarf3, Op::Size4);
86 Descriptions[DW_OP_call_ref] = Desc(Op::Dwarf3, Op::SizeRefAddr);
87 Descriptions[DW_OP_form_tls_address] = Desc(Op::Dwarf3);
88 Descriptions[DW_OP_call_frame_cfa] = Desc(Op::Dwarf3);
89 Descriptions[DW_OP_bit_piece] = Desc(Op::Dwarf3, Op::SizeLEB, Op::SizeLEB);
90 Descriptions[DW_OP_implicit_value] =
91 Desc(Op::Dwarf3, Op::SizeLEB, Op::SizeBlock);
92 Descriptions[DW_OP_stack_value] = Desc(Op::Dwarf3);
93 Descriptions[DW_OP_WASM_location] =
94 Desc(Op::Dwarf4, Op::SizeLEB, Op::WasmLocationArg);
95 Descriptions[DW_OP_GNU_push_tls_address] = Desc(Op::Dwarf3);
96 Descriptions[DW_OP_GNU_addr_index] = Desc(Op::Dwarf4, Op::SizeLEB);
97 Descriptions[DW_OP_GNU_const_index] = Desc(Op::Dwarf4, Op::SizeLEB);
98 Descriptions[DW_OP_GNU_entry_value] = Desc(Op::Dwarf4, Op::SizeLEB);
99 Descriptions[DW_OP_addrx] = Desc(Op::Dwarf5, Op::SizeLEB);
100 Descriptions[DW_OP_constx] = Desc(Op::Dwarf5, Op::SizeLEB);
101 Descriptions[DW_OP_convert] = Desc(Op::Dwarf5, Op::BaseTypeRef);
102 Descriptions[DW_OP_entry_value] = Desc(Op::Dwarf5, Op::SizeLEB);
103 Descriptions[DW_OP_regval_type] =
104 Desc(Op::Dwarf5, Op::SizeLEB, Op::BaseTypeRef);
105 // This Description acts as a marker that getSubOpDesc must be called
106 // to fetch the final Description for the operation. Each such final
107 // Description must share the same first SizeSubOpLEB operand.
108 Descriptions[DW_OP_LLVM_user] = Desc(Op::Dwarf5, Op::SizeSubOpLEB);
109 return Descriptions;
110 }
111
getDescImpl(ArrayRef<Desc> Descriptions,unsigned Opcode)112 static Desc getDescImpl(ArrayRef<Desc> Descriptions, unsigned Opcode) {
113 // Handle possible corrupted or unsupported operation.
114 if (Opcode >= Descriptions.size())
115 return {};
116 return Descriptions[Opcode];
117 }
118
getOpDesc(unsigned Opcode)119 static Desc getOpDesc(unsigned Opcode) {
120 static std::vector<Desc> Descriptions = getOpDescriptions();
121 return getDescImpl(Descriptions, Opcode);
122 }
123
getSubOpDescriptions()124 static std::vector<Desc> getSubOpDescriptions() {
125 static constexpr unsigned LlvmUserDescriptionsSize = 1
126 #define HANDLE_DW_OP_LLVM_USEROP(ID, NAME) +1
127 #include "llvm/BinaryFormat/Dwarf.def"
128 ;
129 std::vector<Desc> Descriptions;
130 Descriptions.resize(LlvmUserDescriptionsSize);
131 Descriptions[DW_OP_LLVM_nop] = Desc(Op::Dwarf5, Op::SizeSubOpLEB);
132 return Descriptions;
133 }
134
getSubOpDesc(unsigned Opcode,unsigned SubOpcode)135 static Desc getSubOpDesc(unsigned Opcode, unsigned SubOpcode) {
136 assert(Opcode == DW_OP_LLVM_user);
137 static std::vector<Desc> Descriptions = getSubOpDescriptions();
138 return getDescImpl(Descriptions, SubOpcode);
139 }
140
extract(DataExtractor Data,uint8_t AddressSize,uint64_t Offset,std::optional<DwarfFormat> Format)141 bool DWARFExpression::Operation::extract(DataExtractor Data,
142 uint8_t AddressSize, uint64_t Offset,
143 std::optional<DwarfFormat> Format) {
144 EndOffset = Offset;
145 Opcode = Data.getU8(&Offset);
146
147 Desc = getOpDesc(Opcode);
148 if (Desc.Version == Operation::DwarfNA)
149 return false;
150
151 Operands.resize(Desc.Op.size());
152 OperandEndOffsets.resize(Desc.Op.size());
153 for (unsigned Operand = 0; Operand < Desc.Op.size(); ++Operand) {
154 unsigned Size = Desc.Op[Operand];
155 unsigned Signed = Size & Operation::SignBit;
156
157 switch (Size & ~Operation::SignBit) {
158 case Operation::SizeSubOpLEB:
159 assert(Operand == 0 && "SubOp operand must be the first operand");
160 Operands[Operand] = Data.getULEB128(&Offset);
161 Desc = getSubOpDesc(Opcode, Operands[Operand]);
162 if (Desc.Version == Operation::DwarfNA)
163 return false;
164 assert(Desc.Op[Operand] == Operation::SizeSubOpLEB &&
165 "SizeSubOpLEB Description must begin with SizeSubOpLEB operand");
166 break;
167 case Operation::Size1:
168 Operands[Operand] = Data.getU8(&Offset);
169 if (Signed)
170 Operands[Operand] = (int8_t)Operands[Operand];
171 break;
172 case Operation::Size2:
173 Operands[Operand] = Data.getU16(&Offset);
174 if (Signed)
175 Operands[Operand] = (int16_t)Operands[Operand];
176 break;
177 case Operation::Size4:
178 Operands[Operand] = Data.getU32(&Offset);
179 if (Signed)
180 Operands[Operand] = (int32_t)Operands[Operand];
181 break;
182 case Operation::Size8:
183 Operands[Operand] = Data.getU64(&Offset);
184 break;
185 case Operation::SizeAddr:
186 Operands[Operand] = Data.getUnsigned(&Offset, AddressSize);
187 break;
188 case Operation::SizeRefAddr:
189 if (!Format)
190 return false;
191 Operands[Operand] =
192 Data.getUnsigned(&Offset, dwarf::getDwarfOffsetByteSize(*Format));
193 break;
194 case Operation::SizeLEB:
195 if (Signed)
196 Operands[Operand] = Data.getSLEB128(&Offset);
197 else
198 Operands[Operand] = Data.getULEB128(&Offset);
199 break;
200 case Operation::BaseTypeRef:
201 Operands[Operand] = Data.getULEB128(&Offset);
202 break;
203 case Operation::WasmLocationArg:
204 assert(Operand == 1);
205 switch (Operands[0]) {
206 case 0:
207 case 1:
208 case 2:
209 case 4:
210 Operands[Operand] = Data.getULEB128(&Offset);
211 break;
212 case 3: // global as uint32
213 Operands[Operand] = Data.getU32(&Offset);
214 break;
215 default:
216 return false; // Unknown Wasm location
217 }
218 break;
219 case Operation::SizeBlock:
220 // We need a size, so this cannot be the first operand
221 if (Operand == 0)
222 return false;
223 // Store the offset of the block as the value.
224 Operands[Operand] = Offset;
225 Offset += Operands[Operand - 1];
226 break;
227 default:
228 llvm_unreachable("Unknown DWARFExpression Op size");
229 }
230
231 OperandEndOffsets[Operand] = Offset;
232 }
233
234 EndOffset = Offset;
235 return true;
236 }
237
prettyPrintBaseTypeRef(DWARFUnit * U,raw_ostream & OS,DIDumpOptions DumpOpts,ArrayRef<uint64_t> Operands,unsigned Operand)238 static void prettyPrintBaseTypeRef(DWARFUnit *U, raw_ostream &OS,
239 DIDumpOptions DumpOpts,
240 ArrayRef<uint64_t> Operands,
241 unsigned Operand) {
242 assert(Operand < Operands.size() && "operand out of bounds");
243 auto Die = U->getDIEForOffset(U->getOffset() + Operands[Operand]);
244 if (Die && Die.getTag() == dwarf::DW_TAG_base_type) {
245 OS << " (";
246 if (DumpOpts.Verbose)
247 OS << format("0x%08" PRIx64 " -> ", Operands[Operand]);
248 OS << format("0x%08" PRIx64 ")", U->getOffset() + Operands[Operand]);
249 if (auto Name = dwarf::toString(Die.find(dwarf::DW_AT_name)))
250 OS << " \"" << *Name << "\"";
251 } else {
252 OS << format(" <invalid base_type ref: 0x%" PRIx64 ">",
253 Operands[Operand]);
254 }
255 }
256
prettyPrintRegisterOp(DWARFUnit * U,raw_ostream & OS,DIDumpOptions DumpOpts,uint8_t Opcode,ArrayRef<uint64_t> Operands)257 bool DWARFExpression::prettyPrintRegisterOp(DWARFUnit *U, raw_ostream &OS,
258 DIDumpOptions DumpOpts,
259 uint8_t Opcode,
260 ArrayRef<uint64_t> Operands) {
261 if (!DumpOpts.GetNameForDWARFReg)
262 return false;
263
264 uint64_t DwarfRegNum;
265 unsigned OpNum = 0;
266
267 if (Opcode == DW_OP_bregx || Opcode == DW_OP_regx ||
268 Opcode == DW_OP_regval_type)
269 DwarfRegNum = Operands[OpNum++];
270 else if (Opcode >= DW_OP_breg0 && Opcode < DW_OP_bregx)
271 DwarfRegNum = Opcode - DW_OP_breg0;
272 else
273 DwarfRegNum = Opcode - DW_OP_reg0;
274
275 auto RegName = DumpOpts.GetNameForDWARFReg(DwarfRegNum, DumpOpts.IsEH);
276 if (!RegName.empty()) {
277 if ((Opcode >= DW_OP_breg0 && Opcode <= DW_OP_breg31) ||
278 Opcode == DW_OP_bregx)
279 OS << ' ' << RegName << format("%+" PRId64, Operands[OpNum]);
280 else
281 OS << ' ' << RegName.data();
282
283 if (Opcode == DW_OP_regval_type)
284 prettyPrintBaseTypeRef(U, OS, DumpOpts, Operands, 1);
285 return true;
286 }
287
288 return false;
289 }
290
getSubCode() const291 std::optional<unsigned> DWARFExpression::Operation::getSubCode() const {
292 if (!Desc.Op.size() || Desc.Op[0] != Operation::SizeSubOpLEB)
293 return std::nullopt;
294 return Operands[0];
295 }
296
print(raw_ostream & OS,DIDumpOptions DumpOpts,const DWARFExpression * Expr,DWARFUnit * U) const297 bool DWARFExpression::Operation::print(raw_ostream &OS, DIDumpOptions DumpOpts,
298 const DWARFExpression *Expr,
299 DWARFUnit *U) const {
300 if (Error) {
301 OS << "<decoding error>";
302 return false;
303 }
304
305 StringRef Name = OperationEncodingString(Opcode);
306 assert(!Name.empty() && "DW_OP has no name!");
307 OS << Name;
308
309 if ((Opcode >= DW_OP_breg0 && Opcode <= DW_OP_breg31) ||
310 (Opcode >= DW_OP_reg0 && Opcode <= DW_OP_reg31) ||
311 Opcode == DW_OP_bregx || Opcode == DW_OP_regx ||
312 Opcode == DW_OP_regval_type)
313 if (prettyPrintRegisterOp(U, OS, DumpOpts, Opcode, Operands))
314 return true;
315
316 for (unsigned Operand = 0; Operand < Desc.Op.size(); ++Operand) {
317 unsigned Size = Desc.Op[Operand];
318 unsigned Signed = Size & Operation::SignBit;
319
320 if (Size == Operation::SizeSubOpLEB) {
321 StringRef SubName = SubOperationEncodingString(Opcode, Operands[Operand]);
322 assert(!SubName.empty() && "DW_OP SubOp has no name!");
323 OS << " " << SubName;
324 } else if (Size == Operation::BaseTypeRef && U) {
325 // For DW_OP_convert the operand may be 0 to indicate that conversion to
326 // the generic type should be done. The same holds for DW_OP_reinterpret,
327 // which is currently not supported.
328 if (Opcode == DW_OP_convert && Operands[Operand] == 0)
329 OS << " 0x0";
330 else
331 prettyPrintBaseTypeRef(U, OS, DumpOpts, Operands, Operand);
332 } else if (Size == Operation::WasmLocationArg) {
333 assert(Operand == 1);
334 switch (Operands[0]) {
335 case 0:
336 case 1:
337 case 2:
338 case 3: // global as uint32
339 case 4:
340 OS << format(" 0x%" PRIx64, Operands[Operand]);
341 break;
342 default: assert(false);
343 }
344 } else if (Size == Operation::SizeBlock) {
345 uint64_t Offset = Operands[Operand];
346 for (unsigned i = 0; i < Operands[Operand - 1]; ++i)
347 OS << format(" 0x%02x", Expr->Data.getU8(&Offset));
348 } else {
349 if (Signed)
350 OS << format(" %+" PRId64, (int64_t)Operands[Operand]);
351 else if (Opcode != DW_OP_entry_value &&
352 Opcode != DW_OP_GNU_entry_value)
353 OS << format(" 0x%" PRIx64, Operands[Operand]);
354 }
355 }
356 return true;
357 }
358
print(raw_ostream & OS,DIDumpOptions DumpOpts,DWARFUnit * U,bool IsEH) const359 void DWARFExpression::print(raw_ostream &OS, DIDumpOptions DumpOpts,
360 DWARFUnit *U, bool IsEH) const {
361 uint32_t EntryValExprSize = 0;
362 uint64_t EntryValStartOffset = 0;
363 if (Data.getData().empty())
364 OS << "<empty>";
365
366 for (auto &Op : *this) {
367 DumpOpts.IsEH = IsEH;
368 if (!Op.print(OS, DumpOpts, this, U)) {
369 uint64_t FailOffset = Op.getEndOffset();
370 while (FailOffset < Data.getData().size())
371 OS << format(" %02x", Data.getU8(&FailOffset));
372 return;
373 }
374
375 if (Op.getCode() == DW_OP_entry_value ||
376 Op.getCode() == DW_OP_GNU_entry_value) {
377 OS << "(";
378 EntryValExprSize = Op.getRawOperand(0);
379 EntryValStartOffset = Op.getEndOffset();
380 continue;
381 }
382
383 if (EntryValExprSize) {
384 EntryValExprSize -= Op.getEndOffset() - EntryValStartOffset;
385 if (EntryValExprSize == 0)
386 OS << ")";
387 }
388
389 if (Op.getEndOffset() < Data.getData().size())
390 OS << ", ";
391 }
392 }
393
verify(const Operation & Op,DWARFUnit * U)394 bool DWARFExpression::Operation::verify(const Operation &Op, DWARFUnit *U) {
395 for (unsigned Operand = 0; Operand < Op.Desc.Op.size(); ++Operand) {
396 unsigned Size = Op.Desc.Op[Operand];
397
398 if (Size == Operation::BaseTypeRef) {
399 // For DW_OP_convert the operand may be 0 to indicate that conversion to
400 // the generic type should be done, so don't look up a base type in that
401 // case. The same holds for DW_OP_reinterpret, which is currently not
402 // supported.
403 if (Op.Opcode == DW_OP_convert && Op.Operands[Operand] == 0)
404 continue;
405 auto Die = U->getDIEForOffset(U->getOffset() + Op.Operands[Operand]);
406 if (!Die || Die.getTag() != dwarf::DW_TAG_base_type)
407 return false;
408 }
409 }
410
411 return true;
412 }
413
verify(DWARFUnit * U)414 bool DWARFExpression::verify(DWARFUnit *U) {
415 for (auto &Op : *this)
416 if (!Operation::verify(Op, U))
417 return false;
418
419 return true;
420 }
421
422 /// A user-facing string representation of a DWARF expression. This might be an
423 /// Address expression, in which case it will be implicitly dereferenced, or a
424 /// Value expression.
425 struct PrintedExpr {
426 enum ExprKind {
427 Address,
428 Value,
429 };
430 ExprKind Kind;
431 SmallString<16> String;
432
PrintedExprllvm::PrintedExpr433 PrintedExpr(ExprKind K = Address) : Kind(K) {}
434 };
435
printCompactDWARFExpr(raw_ostream & OS,DWARFExpression::iterator I,const DWARFExpression::iterator E,std::function<StringRef (uint64_t RegNum,bool IsEH)> GetNameForDWARFReg=nullptr)436 static bool printCompactDWARFExpr(
437 raw_ostream &OS, DWARFExpression::iterator I,
438 const DWARFExpression::iterator E,
439 std::function<StringRef(uint64_t RegNum, bool IsEH)> GetNameForDWARFReg =
440 nullptr) {
441 SmallVector<PrintedExpr, 4> Stack;
442
443 while (I != E) {
444 const DWARFExpression::Operation &Op = *I;
445 uint8_t Opcode = Op.getCode();
446 switch (Opcode) {
447 case dwarf::DW_OP_regx: {
448 // DW_OP_regx: A register, with the register num given as an operand.
449 // Printed as the plain register name.
450 uint64_t DwarfRegNum = Op.getRawOperand(0);
451 auto RegName = GetNameForDWARFReg(DwarfRegNum, false);
452 if (RegName.empty())
453 return false;
454 raw_svector_ostream S(Stack.emplace_back(PrintedExpr::Value).String);
455 S << RegName;
456 break;
457 }
458 case dwarf::DW_OP_bregx: {
459 int DwarfRegNum = Op.getRawOperand(0);
460 int64_t Offset = Op.getRawOperand(1);
461 auto RegName = GetNameForDWARFReg(DwarfRegNum, false);
462 if (RegName.empty())
463 return false;
464 raw_svector_ostream S(Stack.emplace_back().String);
465 S << RegName;
466 if (Offset)
467 S << format("%+" PRId64, Offset);
468 break;
469 }
470 case dwarf::DW_OP_entry_value:
471 case dwarf::DW_OP_GNU_entry_value: {
472 // DW_OP_entry_value contains a sub-expression which must be rendered
473 // separately.
474 uint64_t SubExprLength = Op.getRawOperand(0);
475 DWARFExpression::iterator SubExprEnd = I.skipBytes(SubExprLength);
476 ++I;
477 raw_svector_ostream S(Stack.emplace_back().String);
478 S << "entry(";
479 printCompactDWARFExpr(S, I, SubExprEnd, GetNameForDWARFReg);
480 S << ")";
481 I = SubExprEnd;
482 continue;
483 }
484 case dwarf::DW_OP_stack_value: {
485 // The top stack entry should be treated as the actual value of tne
486 // variable, rather than the address of the variable in memory.
487 assert(!Stack.empty());
488 Stack.back().Kind = PrintedExpr::Value;
489 break;
490 }
491 case dwarf::DW_OP_nop: {
492 break;
493 }
494 case dwarf::DW_OP_LLVM_user: {
495 assert(Op.getSubCode() && *Op.getSubCode() == dwarf::DW_OP_LLVM_nop);
496 break;
497 }
498 default:
499 if (Opcode >= dwarf::DW_OP_reg0 && Opcode <= dwarf::DW_OP_reg31) {
500 // DW_OP_reg<N>: A register, with the register num implied by the
501 // opcode. Printed as the plain register name.
502 uint64_t DwarfRegNum = Opcode - dwarf::DW_OP_reg0;
503 auto RegName = GetNameForDWARFReg(DwarfRegNum, false);
504 if (RegName.empty())
505 return false;
506 raw_svector_ostream S(Stack.emplace_back(PrintedExpr::Value).String);
507 S << RegName;
508 } else if (Opcode >= dwarf::DW_OP_breg0 &&
509 Opcode <= dwarf::DW_OP_breg31) {
510 int DwarfRegNum = Opcode - dwarf::DW_OP_breg0;
511 int64_t Offset = Op.getRawOperand(0);
512 auto RegName = GetNameForDWARFReg(DwarfRegNum, false);
513 if (RegName.empty())
514 return false;
515 raw_svector_ostream S(Stack.emplace_back().String);
516 S << RegName;
517 if (Offset)
518 S << format("%+" PRId64, Offset);
519 } else {
520 // If we hit an unknown operand, we don't know its effect on the stack,
521 // so bail out on the whole expression.
522 OS << "<unknown op " << dwarf::OperationEncodingString(Opcode) << " ("
523 << (int)Opcode << ")>";
524 return false;
525 }
526 break;
527 }
528 ++I;
529 }
530
531 if (Stack.size() != 1) {
532 OS << "<stack of size " << Stack.size() << ", expected 1>";
533 return false;
534 }
535
536 if (Stack.front().Kind == PrintedExpr::Address)
537 OS << "[" << Stack.front().String << "]";
538 else
539 OS << Stack.front().String;
540
541 return true;
542 }
543
printCompact(raw_ostream & OS,std::function<StringRef (uint64_t RegNum,bool IsEH)> GetNameForDWARFReg)544 bool DWARFExpression::printCompact(
545 raw_ostream &OS,
546 std::function<StringRef(uint64_t RegNum, bool IsEH)> GetNameForDWARFReg) {
547 return printCompactDWARFExpr(OS, begin(), end(), GetNameForDWARFReg);
548 }
549
operator ==(const DWARFExpression & RHS) const550 bool DWARFExpression::operator==(const DWARFExpression &RHS) const {
551 if (AddressSize != RHS.AddressSize || Format != RHS.Format)
552 return false;
553 return Data.getData() == RHS.Data.getData();
554 }
555
556 } // namespace llvm
557