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/DebugInfo/DWARF/DWARFUnit.h"
11 #include "llvm/BinaryFormat/Dwarf.h"
12 #include "llvm/MC/MCRegisterInfo.h"
13 #include "llvm/Support/Format.h"
14 #include <cassert>
15 #include <cstdint>
16 #include <vector>
17
18 using namespace llvm;
19 using namespace dwarf;
20
21 namespace llvm {
22
23 typedef std::vector<DWARFExpression::Operation::Description> DescVector;
24
getDescriptions()25 static DescVector getDescriptions() {
26 DescVector Descriptions;
27 typedef DWARFExpression::Operation Op;
28 typedef Op::Description Desc;
29
30 Descriptions.resize(0xff);
31 Descriptions[DW_OP_addr] = Desc(Op::Dwarf2, Op::SizeAddr);
32 Descriptions[DW_OP_deref] = Desc(Op::Dwarf2);
33 Descriptions[DW_OP_const1u] = Desc(Op::Dwarf2, Op::Size1);
34 Descriptions[DW_OP_const1s] = Desc(Op::Dwarf2, Op::SignedSize1);
35 Descriptions[DW_OP_const2u] = Desc(Op::Dwarf2, Op::Size2);
36 Descriptions[DW_OP_const2s] = Desc(Op::Dwarf2, Op::SignedSize2);
37 Descriptions[DW_OP_const4u] = Desc(Op::Dwarf2, Op::Size4);
38 Descriptions[DW_OP_const4s] = Desc(Op::Dwarf2, Op::SignedSize4);
39 Descriptions[DW_OP_const8u] = Desc(Op::Dwarf2, Op::Size8);
40 Descriptions[DW_OP_const8s] = Desc(Op::Dwarf2, Op::SignedSize8);
41 Descriptions[DW_OP_constu] = Desc(Op::Dwarf2, Op::SizeLEB);
42 Descriptions[DW_OP_consts] = Desc(Op::Dwarf2, Op::SignedSizeLEB);
43 Descriptions[DW_OP_dup] = Desc(Op::Dwarf2);
44 Descriptions[DW_OP_drop] = Desc(Op::Dwarf2);
45 Descriptions[DW_OP_over] = Desc(Op::Dwarf2);
46 Descriptions[DW_OP_pick] = Desc(Op::Dwarf2, Op::Size1);
47 Descriptions[DW_OP_swap] = Desc(Op::Dwarf2);
48 Descriptions[DW_OP_rot] = Desc(Op::Dwarf2);
49 Descriptions[DW_OP_xderef] = Desc(Op::Dwarf2);
50 Descriptions[DW_OP_abs] = Desc(Op::Dwarf2);
51 Descriptions[DW_OP_and] = Desc(Op::Dwarf2);
52 Descriptions[DW_OP_div] = Desc(Op::Dwarf2);
53 Descriptions[DW_OP_minus] = Desc(Op::Dwarf2);
54 Descriptions[DW_OP_mod] = Desc(Op::Dwarf2);
55 Descriptions[DW_OP_mul] = Desc(Op::Dwarf2);
56 Descriptions[DW_OP_neg] = Desc(Op::Dwarf2);
57 Descriptions[DW_OP_not] = Desc(Op::Dwarf2);
58 Descriptions[DW_OP_or] = Desc(Op::Dwarf2);
59 Descriptions[DW_OP_plus] = Desc(Op::Dwarf2);
60 Descriptions[DW_OP_plus_uconst] = Desc(Op::Dwarf2, Op::SizeLEB);
61 Descriptions[DW_OP_shl] = Desc(Op::Dwarf2);
62 Descriptions[DW_OP_shr] = Desc(Op::Dwarf2);
63 Descriptions[DW_OP_shra] = Desc(Op::Dwarf2);
64 Descriptions[DW_OP_xor] = Desc(Op::Dwarf2);
65 Descriptions[DW_OP_skip] = Desc(Op::Dwarf2, Op::SignedSize2);
66 Descriptions[DW_OP_bra] = Desc(Op::Dwarf2, Op::SignedSize2);
67 Descriptions[DW_OP_eq] = Desc(Op::Dwarf2);
68 Descriptions[DW_OP_ge] = Desc(Op::Dwarf2);
69 Descriptions[DW_OP_gt] = Desc(Op::Dwarf2);
70 Descriptions[DW_OP_le] = Desc(Op::Dwarf2);
71 Descriptions[DW_OP_lt] = Desc(Op::Dwarf2);
72 Descriptions[DW_OP_ne] = Desc(Op::Dwarf2);
73 for (uint16_t LA = DW_OP_lit0; LA <= DW_OP_lit31; ++LA)
74 Descriptions[LA] = Desc(Op::Dwarf2);
75 for (uint16_t LA = DW_OP_reg0; LA <= DW_OP_reg31; ++LA)
76 Descriptions[LA] = Desc(Op::Dwarf2);
77 for (uint16_t LA = DW_OP_breg0; LA <= DW_OP_breg31; ++LA)
78 Descriptions[LA] = Desc(Op::Dwarf2, Op::SignedSizeLEB);
79 Descriptions[DW_OP_regx] = Desc(Op::Dwarf2, Op::SizeLEB);
80 Descriptions[DW_OP_fbreg] = Desc(Op::Dwarf2, Op::SignedSizeLEB);
81 Descriptions[DW_OP_bregx] = Desc(Op::Dwarf2, Op::SizeLEB, Op::SignedSizeLEB);
82 Descriptions[DW_OP_piece] = Desc(Op::Dwarf2, Op::SizeLEB);
83 Descriptions[DW_OP_deref_size] = Desc(Op::Dwarf2, Op::Size1);
84 Descriptions[DW_OP_xderef_size] = Desc(Op::Dwarf2, Op::Size1);
85 Descriptions[DW_OP_nop] = Desc(Op::Dwarf2);
86 Descriptions[DW_OP_push_object_address] = Desc(Op::Dwarf3);
87 Descriptions[DW_OP_call2] = Desc(Op::Dwarf3, Op::Size2);
88 Descriptions[DW_OP_call4] = Desc(Op::Dwarf3, Op::Size4);
89 Descriptions[DW_OP_call_ref] = Desc(Op::Dwarf3, Op::SizeRefAddr);
90 Descriptions[DW_OP_form_tls_address] = Desc(Op::Dwarf3);
91 Descriptions[DW_OP_call_frame_cfa] = Desc(Op::Dwarf3);
92 Descriptions[DW_OP_bit_piece] = Desc(Op::Dwarf3, Op::SizeLEB, Op::SizeLEB);
93 Descriptions[DW_OP_implicit_value] =
94 Desc(Op::Dwarf3, Op::SizeLEB, Op::SizeBlock);
95 Descriptions[DW_OP_stack_value] = Desc(Op::Dwarf3);
96 Descriptions[DW_OP_WASM_location] =
97 Desc(Op::Dwarf4, Op::SizeLEB, Op::SignedSizeLEB);
98 Descriptions[DW_OP_GNU_push_tls_address] = Desc(Op::Dwarf3);
99 Descriptions[DW_OP_addrx] = Desc(Op::Dwarf4, Op::SizeLEB);
100 Descriptions[DW_OP_GNU_addr_index] = Desc(Op::Dwarf4, Op::SizeLEB);
101 Descriptions[DW_OP_GNU_const_index] = Desc(Op::Dwarf4, Op::SizeLEB);
102 Descriptions[DW_OP_GNU_entry_value] = Desc(Op::Dwarf4, Op::SizeLEB);
103
104 Descriptions[DW_OP_convert] = Desc(Op::Dwarf5, Op::BaseTypeRef);
105 Descriptions[DW_OP_entry_value] = Desc(Op::Dwarf5, Op::SizeLEB);
106
107 return Descriptions;
108 }
109
getOpDesc(unsigned OpCode)110 static DWARFExpression::Operation::Description getOpDesc(unsigned OpCode) {
111 // FIXME: Make this constexpr once all compilers are smart enough to do it.
112 static DescVector Descriptions = getDescriptions();
113 // Handle possible corrupted or unsupported operation.
114 if (OpCode >= Descriptions.size())
115 return {};
116 return Descriptions[OpCode];
117 }
118
getRefAddrSize(uint8_t AddrSize,uint16_t Version)119 static uint8_t getRefAddrSize(uint8_t AddrSize, uint16_t Version) {
120 return (Version == 2) ? AddrSize : 4;
121 }
122
extract(DataExtractor Data,uint16_t Version,uint8_t AddressSize,uint64_t Offset)123 bool DWARFExpression::Operation::extract(DataExtractor Data, uint16_t Version,
124 uint8_t AddressSize, uint64_t Offset) {
125 Opcode = Data.getU8(&Offset);
126
127 Desc = getOpDesc(Opcode);
128 if (Desc.Version == Operation::DwarfNA) {
129 EndOffset = Offset;
130 return false;
131 }
132
133 for (unsigned Operand = 0; Operand < 2; ++Operand) {
134 unsigned Size = Desc.Op[Operand];
135 unsigned Signed = Size & Operation::SignBit;
136
137 if (Size == Operation::SizeNA)
138 break;
139
140 switch (Size & ~Operation::SignBit) {
141 case Operation::Size1:
142 Operands[Operand] = Data.getU8(&Offset);
143 if (Signed)
144 Operands[Operand] = (int8_t)Operands[Operand];
145 break;
146 case Operation::Size2:
147 Operands[Operand] = Data.getU16(&Offset);
148 if (Signed)
149 Operands[Operand] = (int16_t)Operands[Operand];
150 break;
151 case Operation::Size4:
152 Operands[Operand] = Data.getU32(&Offset);
153 if (Signed)
154 Operands[Operand] = (int32_t)Operands[Operand];
155 break;
156 case Operation::Size8:
157 Operands[Operand] = Data.getU64(&Offset);
158 break;
159 case Operation::SizeAddr:
160 if (AddressSize == 8) {
161 Operands[Operand] = Data.getU64(&Offset);
162 } else if (AddressSize == 4) {
163 Operands[Operand] = Data.getU32(&Offset);
164 } else {
165 assert(AddressSize == 2);
166 Operands[Operand] = Data.getU16(&Offset);
167 }
168 break;
169 case Operation::SizeRefAddr:
170 if (getRefAddrSize(AddressSize, Version) == 8) {
171 Operands[Operand] = Data.getU64(&Offset);
172 } else if (getRefAddrSize(AddressSize, Version) == 4) {
173 Operands[Operand] = Data.getU32(&Offset);
174 } else {
175 assert(getRefAddrSize(AddressSize, Version) == 2);
176 Operands[Operand] = Data.getU16(&Offset);
177 }
178 break;
179 case Operation::SizeLEB:
180 if (Signed)
181 Operands[Operand] = Data.getSLEB128(&Offset);
182 else
183 Operands[Operand] = Data.getULEB128(&Offset);
184 break;
185 case Operation::BaseTypeRef:
186 Operands[Operand] = Data.getULEB128(&Offset);
187 break;
188 case Operation::SizeBlock:
189 // We need a size, so this cannot be the first operand
190 if (Operand == 0)
191 return false;
192 // Store the offset of the block as the value.
193 Operands[Operand] = Offset;
194 Offset += Operands[Operand - 1];
195 break;
196 default:
197 llvm_unreachable("Unknown DWARFExpression Op size");
198 }
199
200 OperandEndOffsets[Operand] = Offset;
201 }
202
203 EndOffset = Offset;
204 return true;
205 }
206
prettyPrintRegisterOp(raw_ostream & OS,uint8_t Opcode,uint64_t Operands[2],const MCRegisterInfo * MRI,bool isEH)207 static bool prettyPrintRegisterOp(raw_ostream &OS, uint8_t Opcode,
208 uint64_t Operands[2],
209 const MCRegisterInfo *MRI, bool isEH) {
210 if (!MRI)
211 return false;
212
213 uint64_t DwarfRegNum;
214 unsigned OpNum = 0;
215
216 if (Opcode == DW_OP_bregx || Opcode == DW_OP_regx)
217 DwarfRegNum = Operands[OpNum++];
218 else if (Opcode >= DW_OP_breg0 && Opcode < DW_OP_bregx)
219 DwarfRegNum = Opcode - DW_OP_breg0;
220 else
221 DwarfRegNum = Opcode - DW_OP_reg0;
222
223 if (Optional<unsigned> LLVMRegNum = MRI->getLLVMRegNum(DwarfRegNum, isEH)) {
224 if (const char *RegName = MRI->getName(*LLVMRegNum)) {
225 if ((Opcode >= DW_OP_breg0 && Opcode <= DW_OP_breg31) ||
226 Opcode == DW_OP_bregx)
227 OS << format(" %s%+" PRId64, RegName, Operands[OpNum]);
228 else
229 OS << ' ' << RegName;
230 return true;
231 }
232 }
233
234 return false;
235 }
236
print(raw_ostream & OS,const DWARFExpression * Expr,const MCRegisterInfo * RegInfo,DWARFUnit * U,bool isEH)237 bool DWARFExpression::Operation::print(raw_ostream &OS,
238 const DWARFExpression *Expr,
239 const MCRegisterInfo *RegInfo,
240 DWARFUnit *U,
241 bool isEH) {
242 if (Error) {
243 OS << "<decoding error>";
244 return false;
245 }
246
247 StringRef Name = OperationEncodingString(Opcode);
248 assert(!Name.empty() && "DW_OP has no name!");
249 OS << Name;
250
251 if ((Opcode >= DW_OP_breg0 && Opcode <= DW_OP_breg31) ||
252 (Opcode >= DW_OP_reg0 && Opcode <= DW_OP_reg31) ||
253 Opcode == DW_OP_bregx || Opcode == DW_OP_regx)
254 if (prettyPrintRegisterOp(OS, Opcode, Operands, RegInfo, isEH))
255 return true;
256
257 for (unsigned Operand = 0; Operand < 2; ++Operand) {
258 unsigned Size = Desc.Op[Operand];
259 unsigned Signed = Size & Operation::SignBit;
260
261 if (Size == Operation::SizeNA)
262 break;
263
264 if (Size == Operation::BaseTypeRef && U) {
265 auto Die = U->getDIEForOffset(U->getOffset() + Operands[Operand]);
266 if (Die && Die.getTag() == dwarf::DW_TAG_base_type) {
267 OS << format(" (0x%08" PRIx64 ")", U->getOffset() + Operands[Operand]);
268 if (auto Name = Die.find(dwarf::DW_AT_name))
269 OS << " \"" << Name->getAsCString() << "\"";
270 } else {
271 OS << format(" <invalid base_type ref: 0x%" PRIx64 ">",
272 Operands[Operand]);
273 }
274 } else if (Size == Operation::SizeBlock) {
275 uint64_t Offset = Operands[Operand];
276 for (unsigned i = 0; i < Operands[Operand - 1]; ++i)
277 OS << format(" 0x%02x", Expr->Data.getU8(&Offset));
278 } else {
279 if (Signed)
280 OS << format(" %+" PRId64, (int64_t)Operands[Operand]);
281 else if (Opcode != DW_OP_entry_value &&
282 Opcode != DW_OP_GNU_entry_value)
283 OS << format(" 0x%" PRIx64, Operands[Operand]);
284 }
285 }
286 return true;
287 }
288
print(raw_ostream & OS,const MCRegisterInfo * RegInfo,DWARFUnit * U,bool IsEH) const289 void DWARFExpression::print(raw_ostream &OS, const MCRegisterInfo *RegInfo,
290 DWARFUnit *U, bool IsEH) const {
291 uint32_t EntryValExprSize = 0;
292 for (auto &Op : *this) {
293 if (!Op.print(OS, this, RegInfo, U, IsEH)) {
294 uint64_t FailOffset = Op.getEndOffset();
295 while (FailOffset < Data.getData().size())
296 OS << format(" %02x", Data.getU8(&FailOffset));
297 return;
298 }
299
300 if (Op.getCode() == DW_OP_entry_value ||
301 Op.getCode() == DW_OP_GNU_entry_value) {
302 OS << "(";
303 EntryValExprSize = Op.getRawOperand(0);
304 continue;
305 }
306
307 if (EntryValExprSize) {
308 EntryValExprSize--;
309 if (EntryValExprSize == 0)
310 OS << ")";
311 }
312
313 if (Op.getEndOffset() < Data.getData().size())
314 OS << ", ";
315 }
316 }
317
verify(DWARFUnit * U)318 bool DWARFExpression::Operation::verify(DWARFUnit *U) {
319
320 for (unsigned Operand = 0; Operand < 2; ++Operand) {
321 unsigned Size = Desc.Op[Operand];
322
323 if (Size == Operation::SizeNA)
324 break;
325
326 if (Size == Operation::BaseTypeRef) {
327 auto Die = U->getDIEForOffset(U->getOffset() + Operands[Operand]);
328 if (!Die || Die.getTag() != dwarf::DW_TAG_base_type) {
329 Error = true;
330 return false;
331 }
332 }
333 }
334
335 return true;
336 }
337
verify(DWARFUnit * U)338 bool DWARFExpression::verify(DWARFUnit *U) {
339 for (auto &Op : *this)
340 if (!Op.verify(U))
341 return false;
342
343 return true;
344 }
345
346 } // namespace llvm
347