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 "lldb/Expression/DWARFExpression.h"
10
11#include <cinttypes>
12
13#include <optional>
14#include <vector>
15
16#include "lldb/Core/Module.h"
17#include "lldb/Core/Value.h"
18#include "lldb/Utility/DataEncoder.h"
19#include "lldb/Utility/LLDBLog.h"
20#include "lldb/Utility/Log.h"
21#include "lldb/Utility/RegisterValue.h"
22#include "lldb/Utility/Scalar.h"
23#include "lldb/Utility/StreamString.h"
24#include "lldb/Utility/VMRange.h"
25
26#include "lldb/Host/Host.h"
27#include "lldb/Utility/Endian.h"
28
29#include "lldb/Symbol/Function.h"
30
31#include "lldb/Target/ABI.h"
32#include "lldb/Target/ExecutionContext.h"
33#include "lldb/Target/Process.h"
34#include "lldb/Target/RegisterContext.h"
35#include "lldb/Target/StackFrame.h"
36#include "lldb/Target/StackID.h"
37#include "lldb/Target/Target.h"
38#include "lldb/Target/Thread.h"
39#include "llvm/DebugInfo/DWARF/DWARFExpression.h"
40
41using namespace lldb;
42using namespace lldb_private;
43using namespace lldb_private::dwarf;
44using namespace lldb_private::plugin::dwarf;
45
46// DWARFExpression constructor
47DWARFExpression::DWARFExpression() : m_data() {}
48
49DWARFExpression::DWARFExpression(const DataExtractor &data) : m_data(data) {}
50
51// Destructor
52DWARFExpression::~DWARFExpression() = default;
53
54bool DWARFExpression::IsValid() const { return m_data.GetByteSize() > 0; }
55
56void DWARFExpression::UpdateValue(uint64_t const_value,
57 lldb::offset_t const_value_byte_size,
58 uint8_t addr_byte_size) {
59 if (!const_value_byte_size)
60 return;
61
62 m_data.SetData(
63 data_sp: DataBufferSP(new DataBufferHeap(&const_value, const_value_byte_size)));
64 m_data.SetByteOrder(endian::InlHostByteOrder());
65 m_data.SetAddressByteSize(addr_byte_size);
66}
67
68void DWARFExpression::DumpLocation(Stream *s, lldb::DescriptionLevel level,
69 ABI *abi) const {
70 auto *MCRegInfo = abi ? &abi->GetMCRegisterInfo() : nullptr;
71 auto GetRegName = [&MCRegInfo](uint64_t DwarfRegNum,
72 bool IsEH) -> llvm::StringRef {
73 if (!MCRegInfo)
74 return {};
75 if (std::optional<unsigned> LLVMRegNum =
76 MCRegInfo->getLLVMRegNum(RegNum: DwarfRegNum, isEH: IsEH))
77 if (const char *RegName = MCRegInfo->getName(RegNo: *LLVMRegNum))
78 return llvm::StringRef(RegName);
79 return {};
80 };
81 llvm::DIDumpOptions DumpOpts;
82 DumpOpts.GetNameForDWARFReg = GetRegName;
83 llvm::DWARFExpression E(m_data.GetAsLLVM(), m_data.GetAddressByteSize());
84 llvm::DWARFExpressionPrinter::print(E: &E, OS&: s->AsRawOstream(), DumpOpts, U: nullptr);
85}
86
87RegisterKind DWARFExpression::GetRegisterKind() const { return m_reg_kind; }
88
89void DWARFExpression::SetRegisterKind(RegisterKind reg_kind) {
90 m_reg_kind = reg_kind;
91}
92
93static llvm::Error ReadRegisterValueAsScalar(RegisterContext *reg_ctx,
94 lldb::RegisterKind reg_kind,
95 uint32_t reg_num, Value &value) {
96 if (reg_ctx == nullptr)
97 return llvm::createStringError(Fmt: "no register context in frame");
98
99 const uint32_t native_reg =
100 reg_ctx->ConvertRegisterKindToRegisterNumber(kind: reg_kind, num: reg_num);
101 if (native_reg == LLDB_INVALID_REGNUM)
102 return llvm::createStringError(
103 Fmt: "unable to convert register kind=%u reg_num=%u to a native "
104 "register number",
105 Vals: reg_kind, Vals: reg_num);
106
107 const RegisterInfo *reg_info = reg_ctx->GetRegisterInfoAtIndex(reg: native_reg);
108 RegisterValue reg_value;
109 if (reg_ctx->ReadRegister(reg_info, reg_value)) {
110 if (reg_value.GetScalarValue(scalar&: value.GetScalar())) {
111 value.SetValueType(Value::ValueType::Scalar);
112 value.SetContext(context_type: Value::ContextType::RegisterInfo,
113 p: const_cast<RegisterInfo *>(reg_info));
114 return llvm::Error::success();
115 }
116
117 // If we get this error, then we need to implement a value buffer in
118 // the dwarf expression evaluation function...
119 return llvm::createStringError(
120 Fmt: "register %s can't be converted to a scalar value", Vals: reg_info->name);
121 }
122
123 return llvm::createStringError(Fmt: "register %s is not available",
124 Vals: reg_info->name);
125}
126
127/// Return the length in bytes of the set of operands for \p op. No guarantees
128/// are made on the state of \p data after this call.
129static lldb::offset_t
130GetOpcodeDataSize(const DataExtractor &data, const lldb::offset_t data_offset,
131 const LocationAtom op,
132 const DWARFExpression::Delegate *dwarf_cu) {
133 lldb::offset_t offset = data_offset;
134 switch (op) {
135 // Only used in LLVM metadata.
136 case DW_OP_LLVM_fragment:
137 case DW_OP_LLVM_convert:
138 case DW_OP_LLVM_tag_offset:
139 case DW_OP_LLVM_entry_value:
140 case DW_OP_LLVM_implicit_pointer:
141 case DW_OP_LLVM_arg:
142 case DW_OP_LLVM_extract_bits_sext:
143 case DW_OP_LLVM_extract_bits_zext:
144 break;
145 // Vendor extensions:
146 case DW_OP_HP_is_value:
147 case DW_OP_HP_fltconst4:
148 case DW_OP_HP_fltconst8:
149 case DW_OP_HP_mod_range:
150 case DW_OP_HP_unmod_range:
151 case DW_OP_HP_tls:
152 case DW_OP_INTEL_bit_piece:
153 case DW_OP_WASM_location:
154 case DW_OP_WASM_location_int:
155 case DW_OP_APPLE_uninit:
156 case DW_OP_PGI_omp_thread_num:
157 case DW_OP_hi_user:
158 case DW_OP_GNU_implicit_pointer:
159 break;
160
161 case DW_OP_addr:
162 case DW_OP_call_ref: // 0x9a 1 address sized offset of DIE (DWARF3)
163 return data.GetAddressByteSize();
164
165 // Opcodes with no arguments
166 case DW_OP_deref: // 0x06
167 case DW_OP_dup: // 0x12
168 case DW_OP_drop: // 0x13
169 case DW_OP_over: // 0x14
170 case DW_OP_swap: // 0x16
171 case DW_OP_rot: // 0x17
172 case DW_OP_xderef: // 0x18
173 case DW_OP_abs: // 0x19
174 case DW_OP_and: // 0x1a
175 case DW_OP_div: // 0x1b
176 case DW_OP_minus: // 0x1c
177 case DW_OP_mod: // 0x1d
178 case DW_OP_mul: // 0x1e
179 case DW_OP_neg: // 0x1f
180 case DW_OP_not: // 0x20
181 case DW_OP_or: // 0x21
182 case DW_OP_plus: // 0x22
183 case DW_OP_shl: // 0x24
184 case DW_OP_shr: // 0x25
185 case DW_OP_shra: // 0x26
186 case DW_OP_xor: // 0x27
187 case DW_OP_eq: // 0x29
188 case DW_OP_ge: // 0x2a
189 case DW_OP_gt: // 0x2b
190 case DW_OP_le: // 0x2c
191 case DW_OP_lt: // 0x2d
192 case DW_OP_ne: // 0x2e
193 case DW_OP_lit0: // 0x30
194 case DW_OP_lit1: // 0x31
195 case DW_OP_lit2: // 0x32
196 case DW_OP_lit3: // 0x33
197 case DW_OP_lit4: // 0x34
198 case DW_OP_lit5: // 0x35
199 case DW_OP_lit6: // 0x36
200 case DW_OP_lit7: // 0x37
201 case DW_OP_lit8: // 0x38
202 case DW_OP_lit9: // 0x39
203 case DW_OP_lit10: // 0x3A
204 case DW_OP_lit11: // 0x3B
205 case DW_OP_lit12: // 0x3C
206 case DW_OP_lit13: // 0x3D
207 case DW_OP_lit14: // 0x3E
208 case DW_OP_lit15: // 0x3F
209 case DW_OP_lit16: // 0x40
210 case DW_OP_lit17: // 0x41
211 case DW_OP_lit18: // 0x42
212 case DW_OP_lit19: // 0x43
213 case DW_OP_lit20: // 0x44
214 case DW_OP_lit21: // 0x45
215 case DW_OP_lit22: // 0x46
216 case DW_OP_lit23: // 0x47
217 case DW_OP_lit24: // 0x48
218 case DW_OP_lit25: // 0x49
219 case DW_OP_lit26: // 0x4A
220 case DW_OP_lit27: // 0x4B
221 case DW_OP_lit28: // 0x4C
222 case DW_OP_lit29: // 0x4D
223 case DW_OP_lit30: // 0x4E
224 case DW_OP_lit31: // 0x4f
225 case DW_OP_reg0: // 0x50
226 case DW_OP_reg1: // 0x51
227 case DW_OP_reg2: // 0x52
228 case DW_OP_reg3: // 0x53
229 case DW_OP_reg4: // 0x54
230 case DW_OP_reg5: // 0x55
231 case DW_OP_reg6: // 0x56
232 case DW_OP_reg7: // 0x57
233 case DW_OP_reg8: // 0x58
234 case DW_OP_reg9: // 0x59
235 case DW_OP_reg10: // 0x5A
236 case DW_OP_reg11: // 0x5B
237 case DW_OP_reg12: // 0x5C
238 case DW_OP_reg13: // 0x5D
239 case DW_OP_reg14: // 0x5E
240 case DW_OP_reg15: // 0x5F
241 case DW_OP_reg16: // 0x60
242 case DW_OP_reg17: // 0x61
243 case DW_OP_reg18: // 0x62
244 case DW_OP_reg19: // 0x63
245 case DW_OP_reg20: // 0x64
246 case DW_OP_reg21: // 0x65
247 case DW_OP_reg22: // 0x66
248 case DW_OP_reg23: // 0x67
249 case DW_OP_reg24: // 0x68
250 case DW_OP_reg25: // 0x69
251 case DW_OP_reg26: // 0x6A
252 case DW_OP_reg27: // 0x6B
253 case DW_OP_reg28: // 0x6C
254 case DW_OP_reg29: // 0x6D
255 case DW_OP_reg30: // 0x6E
256 case DW_OP_reg31: // 0x6F
257 case DW_OP_nop: // 0x96
258 case DW_OP_push_object_address: // 0x97 DWARF3
259 case DW_OP_form_tls_address: // 0x9b DWARF3
260 case DW_OP_call_frame_cfa: // 0x9c DWARF3
261 case DW_OP_stack_value: // 0x9f DWARF4
262 case DW_OP_GNU_push_tls_address: // 0xe0 GNU extension
263 return 0;
264
265 // Opcodes with a single 1 byte arguments
266 case DW_OP_const1u: // 0x08 1 1-byte constant
267 case DW_OP_const1s: // 0x09 1 1-byte constant
268 case DW_OP_pick: // 0x15 1 1-byte stack index
269 case DW_OP_deref_size: // 0x94 1 1-byte size of data retrieved
270 case DW_OP_xderef_size: // 0x95 1 1-byte size of data retrieved
271 case DW_OP_deref_type: // 0xa6 1 1-byte constant
272 return 1;
273
274 // Opcodes with a single 2 byte arguments
275 case DW_OP_const2u: // 0x0a 1 2-byte constant
276 case DW_OP_const2s: // 0x0b 1 2-byte constant
277 case DW_OP_skip: // 0x2f 1 signed 2-byte constant
278 case DW_OP_bra: // 0x28 1 signed 2-byte constant
279 case DW_OP_call2: // 0x98 1 2-byte offset of DIE (DWARF3)
280 return 2;
281
282 // Opcodes with a single 4 byte arguments
283 case DW_OP_const4u: // 0x0c 1 4-byte constant
284 case DW_OP_const4s: // 0x0d 1 4-byte constant
285 case DW_OP_call4: // 0x99 1 4-byte offset of DIE (DWARF3)
286 return 4;
287
288 // Opcodes with a single 8 byte arguments
289 case DW_OP_const8u: // 0x0e 1 8-byte constant
290 case DW_OP_const8s: // 0x0f 1 8-byte constant
291 return 8;
292
293 // All opcodes that have a single ULEB (signed or unsigned) argument
294 case DW_OP_constu: // 0x10 1 ULEB128 constant
295 case DW_OP_consts: // 0x11 1 SLEB128 constant
296 case DW_OP_plus_uconst: // 0x23 1 ULEB128 addend
297 case DW_OP_breg0: // 0x70 1 ULEB128 register
298 case DW_OP_breg1: // 0x71 1 ULEB128 register
299 case DW_OP_breg2: // 0x72 1 ULEB128 register
300 case DW_OP_breg3: // 0x73 1 ULEB128 register
301 case DW_OP_breg4: // 0x74 1 ULEB128 register
302 case DW_OP_breg5: // 0x75 1 ULEB128 register
303 case DW_OP_breg6: // 0x76 1 ULEB128 register
304 case DW_OP_breg7: // 0x77 1 ULEB128 register
305 case DW_OP_breg8: // 0x78 1 ULEB128 register
306 case DW_OP_breg9: // 0x79 1 ULEB128 register
307 case DW_OP_breg10: // 0x7a 1 ULEB128 register
308 case DW_OP_breg11: // 0x7b 1 ULEB128 register
309 case DW_OP_breg12: // 0x7c 1 ULEB128 register
310 case DW_OP_breg13: // 0x7d 1 ULEB128 register
311 case DW_OP_breg14: // 0x7e 1 ULEB128 register
312 case DW_OP_breg15: // 0x7f 1 ULEB128 register
313 case DW_OP_breg16: // 0x80 1 ULEB128 register
314 case DW_OP_breg17: // 0x81 1 ULEB128 register
315 case DW_OP_breg18: // 0x82 1 ULEB128 register
316 case DW_OP_breg19: // 0x83 1 ULEB128 register
317 case DW_OP_breg20: // 0x84 1 ULEB128 register
318 case DW_OP_breg21: // 0x85 1 ULEB128 register
319 case DW_OP_breg22: // 0x86 1 ULEB128 register
320 case DW_OP_breg23: // 0x87 1 ULEB128 register
321 case DW_OP_breg24: // 0x88 1 ULEB128 register
322 case DW_OP_breg25: // 0x89 1 ULEB128 register
323 case DW_OP_breg26: // 0x8a 1 ULEB128 register
324 case DW_OP_breg27: // 0x8b 1 ULEB128 register
325 case DW_OP_breg28: // 0x8c 1 ULEB128 register
326 case DW_OP_breg29: // 0x8d 1 ULEB128 register
327 case DW_OP_breg30: // 0x8e 1 ULEB128 register
328 case DW_OP_breg31: // 0x8f 1 ULEB128 register
329 case DW_OP_regx: // 0x90 1 ULEB128 register
330 case DW_OP_fbreg: // 0x91 1 SLEB128 offset
331 case DW_OP_piece: // 0x93 1 ULEB128 size of piece addressed
332 case DW_OP_convert: // 0xa8 1 ULEB128 offset
333 case DW_OP_reinterpret: // 0xa9 1 ULEB128 offset
334 case DW_OP_addrx: // 0xa1 1 ULEB128 index
335 case DW_OP_constx: // 0xa2 1 ULEB128 index
336 case DW_OP_xderef_type: // 0xa7 1 ULEB128 index
337 case DW_OP_GNU_addr_index: // 0xfb 1 ULEB128 index
338 case DW_OP_GNU_const_index: // 0xfc 1 ULEB128 index
339 data.Skip_LEB128(offset_ptr: &offset);
340 return offset - data_offset;
341
342 // All opcodes that have a 2 ULEB (signed or unsigned) arguments
343 case DW_OP_bregx: // 0x92 2 ULEB128 register followed by SLEB128 offset
344 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3);
345 case DW_OP_regval_type: // 0xa5 ULEB128 + ULEB128
346 data.Skip_LEB128(offset_ptr: &offset);
347 data.Skip_LEB128(offset_ptr: &offset);
348 return offset - data_offset;
349
350 case DW_OP_implicit_value: // 0x9e ULEB128 size followed by block of that size
351 // (DWARF4)
352 {
353 uint64_t block_len = data.Skip_LEB128(offset_ptr: &offset);
354 offset += block_len;
355 return offset - data_offset;
356 }
357
358 case DW_OP_implicit_pointer: // 0xa0 4-byte (or 8-byte for DWARF 64) constant
359 // + LEB128
360 {
361 data.Skip_LEB128(offset_ptr: &offset);
362 return (dwarf_cu ? dwarf_cu->GetAddressByteSize() : 4) + offset -
363 data_offset;
364 }
365
366 case DW_OP_GNU_entry_value:
367 case DW_OP_entry_value: // 0xa3 ULEB128 size + variable-length block
368 {
369 uint64_t subexpr_len = data.GetULEB128(offset_ptr: &offset);
370 return (offset - data_offset) + subexpr_len;
371 }
372
373 case DW_OP_const_type: // 0xa4 ULEB128 + size + variable-length block
374 {
375 data.Skip_LEB128(offset_ptr: &offset);
376 uint8_t length = data.GetU8(offset_ptr: &offset);
377 return (offset - data_offset) + length;
378 }
379
380 case DW_OP_LLVM_user: // 0xe9: ULEB128 + variable length constant
381 {
382 uint64_t constants = data.GetULEB128(offset_ptr: &offset);
383 return (offset - data_offset) + constants;
384 }
385 }
386
387 if (dwarf_cu)
388 return dwarf_cu->GetVendorDWARFOpcodeSize(data, data_offset, op);
389
390 return LLDB_INVALID_OFFSET;
391}
392
393static const char *DW_OP_value_to_name(uint32_t val) {
394 static char invalid[100];
395 llvm::StringRef llvmstr = llvm::dwarf::OperationEncodingString(Encoding: val);
396 if (llvmstr.empty()) {
397 snprintf(s: invalid, maxlen: sizeof(invalid), format: "Unknown DW_OP constant: 0x%x", val);
398 return invalid;
399 }
400 return llvmstr.data();
401}
402
403llvm::Expected<lldb::addr_t> DWARFExpression::GetLocation_DW_OP_addr(
404 const DWARFExpression::Delegate *dwarf_cu) const {
405 lldb::offset_t offset = 0;
406 while (m_data.ValidOffset(offset)) {
407 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(offset_ptr: &offset));
408
409 if (op == DW_OP_addr)
410 return m_data.GetAddress(offset_ptr: &offset);
411
412 if (op == DW_OP_GNU_addr_index || op == DW_OP_addrx) {
413 const uint64_t index = m_data.GetULEB128(offset_ptr: &offset);
414 if (dwarf_cu)
415 return dwarf_cu->ReadAddressFromDebugAddrSection(index);
416 return llvm::createStringError(Fmt: "cannot evaluate %s without a DWARF unit",
417 Vals: DW_OP_value_to_name(val: op));
418 }
419
420 const lldb::offset_t op_arg_size =
421 GetOpcodeDataSize(data: m_data, data_offset: offset, op, dwarf_cu);
422 if (op_arg_size == LLDB_INVALID_OFFSET)
423 return llvm::createStringError(Fmt: "cannot get opcode data size for %s",
424 Vals: DW_OP_value_to_name(val: op));
425
426 offset += op_arg_size;
427 }
428
429 return LLDB_INVALID_ADDRESS;
430}
431
432bool DWARFExpression::Update_DW_OP_addr(
433 const DWARFExpression::Delegate *dwarf_cu, lldb::addr_t file_addr) {
434 lldb::offset_t offset = 0;
435 while (m_data.ValidOffset(offset)) {
436 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(offset_ptr: &offset));
437
438 if (op == DW_OP_addr) {
439 const uint32_t addr_byte_size = m_data.GetAddressByteSize();
440 // We have to make a copy of the data as we don't know if this data is
441 // from a read only memory mapped buffer, so we duplicate all of the data
442 // first, then modify it, and if all goes well, we then replace the data
443 // for this expression
444
445 // Make en encoder that contains a copy of the location expression data
446 // so we can write the address into the buffer using the correct byte
447 // order.
448 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(),
449 m_data.GetByteOrder(), addr_byte_size);
450
451 // Replace the address in the new buffer
452 if (encoder.PutAddress(offset, addr: file_addr) == UINT32_MAX)
453 return false;
454
455 // All went well, so now we can reset the data using a shared pointer to
456 // the heap data so "m_data" will now correctly manage the heap data.
457 m_data.SetData(data_sp: encoder.GetDataBuffer());
458 return true;
459 }
460 if (op == DW_OP_addrx) {
461 // Replace DW_OP_addrx with DW_OP_addr, since we can't modify the
462 // read-only debug_addr table.
463 // Subtract one to account for the opcode.
464 llvm::ArrayRef data_before_op = m_data.GetData().take_front(N: offset - 1);
465
466 // Read the addrx index to determine how many bytes it needs.
467 const lldb::offset_t old_offset = offset;
468 m_data.GetULEB128(offset_ptr: &offset);
469 if (old_offset == offset)
470 return false;
471 llvm::ArrayRef data_after_op = m_data.GetData().drop_front(N: offset);
472
473 DataEncoder encoder(m_data.GetByteOrder(), m_data.GetAddressByteSize());
474 encoder.AppendData(data: data_before_op);
475 encoder.AppendU8(value: DW_OP_addr);
476 encoder.AppendAddress(addr: file_addr);
477 encoder.AppendData(data: data_after_op);
478 m_data.SetData(data_sp: encoder.GetDataBuffer());
479 return true;
480 }
481 const lldb::offset_t op_arg_size =
482 GetOpcodeDataSize(data: m_data, data_offset: offset, op, dwarf_cu);
483 if (op_arg_size == LLDB_INVALID_OFFSET)
484 break;
485 offset += op_arg_size;
486 }
487 return false;
488}
489
490bool DWARFExpression::ContainsThreadLocalStorage(
491 const DWARFExpression::Delegate *dwarf_cu) const {
492 lldb::offset_t offset = 0;
493 while (m_data.ValidOffset(offset)) {
494 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(offset_ptr: &offset));
495
496 if (op == DW_OP_form_tls_address || op == DW_OP_GNU_push_tls_address)
497 return true;
498 const lldb::offset_t op_arg_size =
499 GetOpcodeDataSize(data: m_data, data_offset: offset, op, dwarf_cu);
500 if (op_arg_size == LLDB_INVALID_OFFSET)
501 return false;
502 offset += op_arg_size;
503 }
504 return false;
505}
506bool DWARFExpression::LinkThreadLocalStorage(
507 const DWARFExpression::Delegate *dwarf_cu,
508 std::function<lldb::addr_t(lldb::addr_t file_addr)> const
509 &link_address_callback) {
510 const uint32_t addr_byte_size = m_data.GetAddressByteSize();
511 // We have to make a copy of the data as we don't know if this data is from a
512 // read only memory mapped buffer, so we duplicate all of the data first,
513 // then modify it, and if all goes well, we then replace the data for this
514 // expression.
515 // Make en encoder that contains a copy of the location expression data so we
516 // can write the address into the buffer using the correct byte order.
517 DataEncoder encoder(m_data.GetDataStart(), m_data.GetByteSize(),
518 m_data.GetByteOrder(), addr_byte_size);
519
520 lldb::offset_t offset = 0;
521 lldb::offset_t const_offset = 0;
522 lldb::addr_t const_value = 0;
523 size_t const_byte_size = 0;
524 while (m_data.ValidOffset(offset)) {
525 const LocationAtom op = static_cast<LocationAtom>(m_data.GetU8(offset_ptr: &offset));
526
527 bool decoded_data = false;
528 switch (op) {
529 case DW_OP_const4u:
530 // Remember the const offset in case we later have a
531 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address
532 const_offset = offset;
533 const_value = m_data.GetU32(offset_ptr: &offset);
534 decoded_data = true;
535 const_byte_size = 4;
536 break;
537
538 case DW_OP_const8u:
539 // Remember the const offset in case we later have a
540 // DW_OP_form_tls_address or DW_OP_GNU_push_tls_address
541 const_offset = offset;
542 const_value = m_data.GetU64(offset_ptr: &offset);
543 decoded_data = true;
544 const_byte_size = 8;
545 break;
546
547 case DW_OP_form_tls_address:
548 case DW_OP_GNU_push_tls_address:
549 // DW_OP_form_tls_address and DW_OP_GNU_push_tls_address must be preceded
550 // by a file address on the stack. We assume that DW_OP_const4u or
551 // DW_OP_const8u is used for these values, and we check that the last
552 // opcode we got before either of these was DW_OP_const4u or
553 // DW_OP_const8u. If so, then we can link the value accordingly. For
554 // Darwin, the value in the DW_OP_const4u or DW_OP_const8u is the file
555 // address of a structure that contains a function pointer, the pthread
556 // key and the offset into the data pointed to by the pthread key. So we
557 // must link this address and also set the module of this expression to
558 // the new_module_sp so we can resolve the file address correctly
559 if (const_byte_size > 0) {
560 lldb::addr_t linked_file_addr = link_address_callback(const_value);
561 if (linked_file_addr == LLDB_INVALID_ADDRESS)
562 return false;
563 // Replace the address in the new buffer
564 if (encoder.PutUnsigned(offset: const_offset, byte_size: const_byte_size,
565 value: linked_file_addr) == UINT32_MAX)
566 return false;
567 }
568 break;
569
570 default:
571 const_offset = 0;
572 const_value = 0;
573 const_byte_size = 0;
574 break;
575 }
576
577 if (!decoded_data) {
578 const lldb::offset_t op_arg_size =
579 GetOpcodeDataSize(data: m_data, data_offset: offset, op, dwarf_cu);
580 if (op_arg_size == LLDB_INVALID_OFFSET)
581 return false;
582 else
583 offset += op_arg_size;
584 }
585 }
586
587 m_data.SetData(data_sp: encoder.GetDataBuffer());
588 return true;
589}
590
591static llvm::Error Evaluate_DW_OP_entry_value(std::vector<Value> &stack,
592 ExecutionContext *exe_ctx,
593 RegisterContext *reg_ctx,
594 const DataExtractor &opcodes,
595 lldb::offset_t &opcode_offset,
596 Log *log) {
597 // DW_OP_entry_value(sub-expr) describes the location a variable had upon
598 // function entry: this variable location is presumed to be optimized out at
599 // the current PC value. The caller of the function may have call site
600 // information that describes an alternate location for the variable (e.g. a
601 // constant literal, or a spilled stack value) in the parent frame.
602 //
603 // Example (this is pseudo-code & pseudo-DWARF, but hopefully illustrative):
604 //
605 // void child(int &sink, int x) {
606 // ...
607 // /* "x" gets optimized out. */
608 //
609 // /* The location of "x" here is: DW_OP_entry_value($reg2). */
610 // ++sink;
611 // }
612 //
613 // void parent() {
614 // int sink;
615 //
616 // /*
617 // * The callsite information emitted here is:
618 // *
619 // * DW_TAG_call_site
620 // * DW_AT_return_pc ... (for "child(sink, 123);")
621 // * DW_TAG_call_site_parameter (for "sink")
622 // * DW_AT_location ($reg1)
623 // * DW_AT_call_value ($SP - 8)
624 // * DW_TAG_call_site_parameter (for "x")
625 // * DW_AT_location ($reg2)
626 // * DW_AT_call_value ($literal 123)
627 // *
628 // * DW_TAG_call_site
629 // * DW_AT_return_pc ... (for "child(sink, 456);")
630 // * ...
631 // */
632 // child(sink, 123);
633 // child(sink, 456);
634 // }
635 //
636 // When the program stops at "++sink" within `child`, the debugger determines
637 // the call site by analyzing the return address. Once the call site is found,
638 // the debugger determines which parameter is referenced by DW_OP_entry_value
639 // and evaluates the corresponding location for that parameter in `parent`.
640
641 // 1. Find the function which pushed the current frame onto the stack.
642 if ((!exe_ctx || !exe_ctx->HasTargetScope()) || !reg_ctx) {
643 return llvm::createStringError(Fmt: "no exe/reg context");
644 }
645
646 StackFrame *current_frame = exe_ctx->GetFramePtr();
647 Thread *thread = exe_ctx->GetThreadPtr();
648 if (!current_frame || !thread)
649 return llvm::createStringError(Fmt: "no current frame/thread");
650
651 Target &target = exe_ctx->GetTargetRef();
652 StackFrameSP parent_frame = nullptr;
653 addr_t return_pc = LLDB_INVALID_ADDRESS;
654 uint32_t current_frame_idx = current_frame->GetFrameIndex();
655
656 for (uint32_t parent_frame_idx = current_frame_idx + 1;;parent_frame_idx++) {
657 parent_frame = thread->GetStackFrameAtIndex(idx: parent_frame_idx);
658 // If this is null, we're at the end of the stack.
659 if (!parent_frame)
660 break;
661
662 // Record the first valid return address, even if this is an inlined frame,
663 // in order to look up the associated call edge in the first non-inlined
664 // parent frame.
665 if (return_pc == LLDB_INVALID_ADDRESS) {
666 return_pc = parent_frame->GetFrameCodeAddress().GetLoadAddress(target: &target);
667 LLDB_LOG(log, "immediate ancestor with pc = {0:x}", return_pc);
668 }
669
670 // If we've found an inlined frame, skip it (these have no call site
671 // parameters).
672 if (parent_frame->IsInlined())
673 continue;
674
675 // We've found the first non-inlined parent frame.
676 break;
677 }
678 if (!parent_frame || !parent_frame->GetRegisterContext()) {
679 return llvm::createStringError(Fmt: "no parent frame with reg ctx");
680 }
681
682 Function *parent_func =
683 parent_frame->GetSymbolContext(resolve_scope: eSymbolContextFunction).function;
684 if (!parent_func)
685 return llvm::createStringError(Fmt: "no parent function");
686
687 // 2. Find the call edge in the parent function responsible for creating the
688 // current activation.
689 Function *current_func =
690 current_frame->GetSymbolContext(resolve_scope: eSymbolContextFunction).function;
691 if (!current_func)
692 return llvm::createStringError(Fmt: "no current function");
693
694 CallEdge *call_edge = nullptr;
695 ModuleList &modlist = target.GetImages();
696 ExecutionContext parent_exe_ctx = *exe_ctx;
697 parent_exe_ctx.SetFrameSP(parent_frame);
698 if (!parent_frame->IsArtificial()) {
699 // If the parent frame is not artificial, the current activation may be
700 // produced by an ambiguous tail call. In this case, refuse to proceed.
701 call_edge = parent_func->GetCallEdgeForReturnAddress(return_pc, target);
702 if (!call_edge) {
703 return llvm::createStringError(
704 S: llvm::formatv(Fmt: "no call edge for retn-pc = {0:x} in parent frame {1}",
705 Vals&: return_pc, Vals: parent_func->GetName()));
706 }
707 Function *callee_func = call_edge->GetCallee(images&: modlist, exe_ctx&: parent_exe_ctx);
708 if (callee_func != current_func) {
709 return llvm::createStringError(
710 Fmt: "ambiguous call sequence, can't find real parent frame");
711 }
712 } else {
713 // The StackFrameList solver machinery has deduced that an unambiguous tail
714 // call sequence that produced the current activation. The first edge in
715 // the parent that points to the current function must be valid.
716 for (auto &edge : parent_func->GetTailCallingEdges()) {
717 if (edge->GetCallee(images&: modlist, exe_ctx&: parent_exe_ctx) == current_func) {
718 call_edge = edge.get();
719 break;
720 }
721 }
722 }
723 if (!call_edge)
724 return llvm::createStringError(Fmt: "no unambiguous edge from parent "
725 "to current function");
726
727 // 3. Attempt to locate the DW_OP_entry_value expression in the set of
728 // available call site parameters. If found, evaluate the corresponding
729 // parameter in the context of the parent frame.
730 const uint32_t subexpr_len = opcodes.GetULEB128(offset_ptr: &opcode_offset);
731 const void *subexpr_data = opcodes.GetData(offset_ptr: &opcode_offset, length: subexpr_len);
732 if (!subexpr_data)
733 return llvm::createStringError(Fmt: "subexpr could not be read");
734
735 const CallSiteParameter *matched_param = nullptr;
736 for (const CallSiteParameter &param : call_edge->GetCallSiteParameters()) {
737 DataExtractor param_subexpr_extractor;
738 if (!param.LocationInCallee.GetExpressionData(data&: param_subexpr_extractor))
739 continue;
740 lldb::offset_t param_subexpr_offset = 0;
741 const void *param_subexpr_data =
742 param_subexpr_extractor.GetData(offset_ptr: &param_subexpr_offset, length: subexpr_len);
743 if (!param_subexpr_data ||
744 param_subexpr_extractor.BytesLeft(offset: param_subexpr_offset) != 0)
745 continue;
746
747 // At this point, the DW_OP_entry_value sub-expression and the callee-side
748 // expression in the call site parameter are known to have the same length.
749 // Check whether they are equal.
750 //
751 // Note that an equality check is sufficient: the contents of the
752 // DW_OP_entry_value subexpression are only used to identify the right call
753 // site parameter in the parent, and do not require any special handling.
754 if (memcmp(s1: subexpr_data, s2: param_subexpr_data, n: subexpr_len) == 0) {
755 matched_param = &param;
756 break;
757 }
758 }
759 if (!matched_param)
760 return llvm::createStringError(Fmt: "no matching call site param found");
761
762 // TODO: Add support for DW_OP_push_object_address within a DW_OP_entry_value
763 // subexpresion whenever llvm does.
764 const DWARFExpressionList &param_expr = matched_param->LocationInCaller;
765
766 llvm::Expected<Value> maybe_result = param_expr.Evaluate(
767 exe_ctx: &parent_exe_ctx, reg_ctx: parent_frame->GetRegisterContext().get(),
768 LLDB_INVALID_ADDRESS,
769 /*initial_value_ptr=*/nullptr,
770 /*object_address_ptr=*/nullptr);
771 if (!maybe_result) {
772 LLDB_LOG(log,
773 "Evaluate_DW_OP_entry_value: call site param evaluation failed");
774 return maybe_result.takeError();
775 }
776
777 stack.push_back(x: *maybe_result);
778 return llvm::Error::success();
779}
780
781namespace {
782/// The location description kinds described by the DWARF v5
783/// specification. Composite locations are handled out-of-band and
784/// thus aren't part of the enum.
785enum LocationDescriptionKind {
786 Empty,
787 Memory,
788 Register,
789 Implicit
790 /* Composite*/
791};
792/// Adjust value's ValueType according to the kind of location description.
793void UpdateValueTypeFromLocationDescription(
794 Log *log, const DWARFExpression::Delegate *dwarf_cu,
795 LocationDescriptionKind kind, Value *value = nullptr) {
796 // Note that this function is conflating DWARF expressions with
797 // DWARF location descriptions. Perhaps it would be better to define
798 // a wrapper for DWARFExpression::Eval() that deals with DWARF
799 // location descriptions (which consist of one or more DWARF
800 // expressions). But doing this would mean we'd also need factor the
801 // handling of DW_OP_(bit_)piece out of this function.
802 if (dwarf_cu && dwarf_cu->GetVersion() >= 4) {
803 const char *log_msg = "DWARF location description kind: %s";
804 switch (kind) {
805 case Empty:
806 LLDB_LOGF(log, log_msg, "Empty");
807 break;
808 case Memory:
809 LLDB_LOGF(log, log_msg, "Memory");
810 if (value->GetValueType() == Value::ValueType::Scalar)
811 value->SetValueType(Value::ValueType::LoadAddress);
812 break;
813 case Register:
814 LLDB_LOGF(log, log_msg, "Register");
815 value->SetValueType(Value::ValueType::Scalar);
816 break;
817 case Implicit:
818 LLDB_LOGF(log, log_msg, "Implicit");
819 if (value->GetValueType() == Value::ValueType::LoadAddress)
820 value->SetValueType(Value::ValueType::Scalar);
821 break;
822 }
823 }
824}
825} // namespace
826
827/// Helper function to move common code used to resolve a file address and turn
828/// into a load address.
829///
830/// \param exe_ctx Pointer to the execution context
831/// \param module_sp shared_ptr contains the module if we have one
832/// \param dw_op_type C-style string used to vary the error output
833/// \param file_addr the file address we are trying to resolve and turn into a
834/// load address
835/// \param so_addr out parameter, will be set to load address or section offset
836/// \param check_sectionoffset bool which determines if having a section offset
837/// but not a load address is considerd a success
838/// \returns std::optional containing the load address if resolving and getting
839/// the load address succeed or an empty Optinal otherwise. If
840/// check_sectionoffset is true we consider LLDB_INVALID_ADDRESS a
841/// success if so_addr.IsSectionOffset() is true.
842static llvm::Expected<lldb::addr_t>
843ResolveLoadAddress(ExecutionContext *exe_ctx, lldb::ModuleSP &module_sp,
844 const char *dw_op_type, lldb::addr_t file_addr,
845 Address &so_addr, bool check_sectionoffset = false) {
846 if (!module_sp)
847 return llvm::createStringError(Fmt: "need module to resolve file address for %s",
848 Vals: dw_op_type);
849
850 if (!module_sp->ResolveFileAddress(vm_addr: file_addr, so_addr))
851 return llvm::createStringError(Fmt: "failed to resolve file address in module");
852
853 const addr_t load_addr = so_addr.GetLoadAddress(target: exe_ctx->GetTargetPtr());
854
855 if (load_addr == LLDB_INVALID_ADDRESS &&
856 (check_sectionoffset && !so_addr.IsSectionOffset()))
857 return llvm::createStringError(Fmt: "failed to resolve load address");
858
859 return load_addr;
860}
861
862/// Helper function to move common code used to load sized data from a uint8_t
863/// buffer.
864///
865/// \param addr_bytes uint8_t buffer containg raw data
866/// \param size_addr_bytes how large is the underlying raw data
867/// \param byte_order what is the byter order of the underlyig data
868/// \param size How much of the underlying data we want to use
869/// \return The underlying data converted into a Scalar
870static Scalar DerefSizeExtractDataHelper(uint8_t *addr_bytes,
871 size_t size_addr_bytes,
872 ByteOrder byte_order, size_t size) {
873 DataExtractor addr_data(addr_bytes, size_addr_bytes, byte_order, size);
874
875 lldb::offset_t addr_data_offset = 0;
876 if (size <= 8)
877 return addr_data.GetMaxU64(offset_ptr: &addr_data_offset, byte_size: size);
878 else
879 return addr_data.GetAddress(offset_ptr: &addr_data_offset);
880}
881
882llvm::Expected<Value> DWARFExpression::Evaluate(
883 ExecutionContext *exe_ctx, RegisterContext *reg_ctx,
884 lldb::ModuleSP module_sp, const DataExtractor &opcodes,
885 const DWARFExpression::Delegate *dwarf_cu,
886 const lldb::RegisterKind reg_kind, const Value *initial_value_ptr,
887 const Value *object_address_ptr) {
888
889 if (opcodes.GetByteSize() == 0)
890 return llvm::createStringError(
891 Fmt: "no location, value may have been optimized out");
892 std::vector<Value> stack;
893
894 Process *process = nullptr;
895 StackFrame *frame = nullptr;
896 Target *target = nullptr;
897
898 if (exe_ctx) {
899 process = exe_ctx->GetProcessPtr();
900 frame = exe_ctx->GetFramePtr();
901 target = exe_ctx->GetTargetPtr();
902 }
903 if (reg_ctx == nullptr && frame)
904 reg_ctx = frame->GetRegisterContext().get();
905
906 if (initial_value_ptr)
907 stack.push_back(x: *initial_value_ptr);
908
909 lldb::offset_t offset = 0;
910 Value tmp;
911 uint32_t reg_num;
912
913 /// Insertion point for evaluating multi-piece expression.
914 uint64_t op_piece_offset = 0;
915 Value pieces; // Used for DW_OP_piece
916
917 Log *log = GetLog(mask: LLDBLog::Expressions);
918 // A generic type is "an integral type that has the size of an address and an
919 // unspecified signedness". For now, just use the signedness of the operand.
920 // TODO: Implement a real typed stack, and store the genericness of the value
921 // there.
922 auto to_generic = [&](auto v) {
923 // TODO: Avoid implicit trunc?
924 // See https://github.com/llvm/llvm-project/issues/112510.
925 bool is_signed = std::is_signed<decltype(v)>::value;
926 return Scalar(llvm::APSInt(llvm::APInt(8 * opcodes.GetAddressByteSize(), v,
927 is_signed, /*implicitTrunc=*/true),
928 !is_signed));
929 };
930
931 // The default kind is a memory location. This is updated by any
932 // operation that changes this, such as DW_OP_stack_value, and reset
933 // by composition operations like DW_OP_piece.
934 LocationDescriptionKind dwarf4_location_description_kind = Memory;
935
936 while (opcodes.ValidOffset(offset)) {
937 const lldb::offset_t op_offset = offset;
938 const uint8_t op = opcodes.GetU8(offset_ptr: &offset);
939
940 if (log && log->GetVerbose()) {
941 size_t count = stack.size();
942 LLDB_LOGF(log, "Stack before operation has %" PRIu64 " values:",
943 (uint64_t)count);
944 for (size_t i = 0; i < count; ++i) {
945 StreamString new_value;
946 new_value.Printf(format: "[%" PRIu64 "]", (uint64_t)i);
947 stack[i].Dump(strm: &new_value);
948 LLDB_LOGF(log, " %s", new_value.GetData());
949 }
950 LLDB_LOGF(log, "0x%8.8" PRIx64 ": %s", op_offset,
951 DW_OP_value_to_name(op));
952 }
953
954 if (std::optional<unsigned> arity =
955 llvm::dwarf::OperationArity(O: static_cast<LocationAtom>(op))) {
956 if (stack.size() < *arity)
957 return llvm::createStringError(
958 Fmt: "%s needs at least %d stack entries (stack has %d entries)",
959 Vals: DW_OP_value_to_name(val: op), Vals: *arity, Vals: stack.size());
960 }
961
962 switch (op) {
963 // The DW_OP_addr operation has a single operand that encodes a machine
964 // address and whose size is the size of an address on the target machine.
965 case DW_OP_addr:
966 stack.push_back(x: Scalar(opcodes.GetAddress(offset_ptr: &offset)));
967 if (target &&
968 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) {
969 // wasm file sections aren't mapped into memory, therefore addresses can
970 // never point into a file section and are always LoadAddresses.
971 stack.back().SetValueType(Value::ValueType::LoadAddress);
972 } else {
973 stack.back().SetValueType(Value::ValueType::FileAddress);
974 }
975 break;
976
977 // The DW_OP_addr_sect_offset4 is used for any location expressions in
978 // shared libraries that have a location like:
979 // DW_OP_addr(0x1000)
980 // If this address resides in a shared library, then this virtual address
981 // won't make sense when it is evaluated in the context of a running
982 // process where shared libraries have been slid. To account for this, this
983 // new address type where we can store the section pointer and a 4 byte
984 // offset.
985 // case DW_OP_addr_sect_offset4:
986 // {
987 // result_type = eResultTypeFileAddress;
988 // lldb::Section *sect = (lldb::Section
989 // *)opcodes.GetMaxU64(&offset, sizeof(void *));
990 // lldb::addr_t sect_offset = opcodes.GetU32(&offset);
991 //
992 // Address so_addr (sect, sect_offset);
993 // lldb::addr_t load_addr = so_addr.GetLoadAddress();
994 // if (load_addr != LLDB_INVALID_ADDRESS)
995 // {
996 // // We successfully resolve a file address to a load
997 // // address.
998 // stack.push_back(load_addr);
999 // break;
1000 // }
1001 // else
1002 // {
1003 // // We were able
1004 // if (error_ptr)
1005 // error_ptr->SetErrorStringWithFormat ("Section %s in
1006 // %s is not currently loaded.\n",
1007 // sect->GetName().AsCString(),
1008 // sect->GetModule()->GetFileSpec().GetFilename().AsCString());
1009 // return false;
1010 // }
1011 // }
1012 // break;
1013
1014 // OPCODE: DW_OP_deref
1015 // OPERANDS: none
1016 // DESCRIPTION: Pops the top stack entry and treats it as an address.
1017 // The value retrieved from that address is pushed. The size of the data
1018 // retrieved from the dereferenced address is the size of an address on the
1019 // target machine.
1020 case DW_OP_deref: {
1021 if (stack.empty())
1022 return llvm::createStringError(
1023 Fmt: "expression stack empty for DW_OP_deref");
1024 Value::ValueType value_type = stack.back().GetValueType();
1025 switch (value_type) {
1026 case Value::ValueType::HostAddress: {
1027 void *src = (void *)stack.back().GetScalar().ULongLong();
1028 intptr_t ptr;
1029 ::memcpy(dest: &ptr, src: src, n: sizeof(void *));
1030 stack.back().GetScalar() = ptr;
1031 stack.back().ClearContext();
1032 } break;
1033 case Value::ValueType::FileAddress: {
1034 auto file_addr = stack.back().GetScalar().ULongLong(
1035 LLDB_INVALID_ADDRESS);
1036
1037 Address so_addr;
1038 auto maybe_load_addr = ResolveLoadAddress(
1039 exe_ctx, module_sp, dw_op_type: "DW_OP_deref", file_addr, so_addr);
1040
1041 if (!maybe_load_addr)
1042 return maybe_load_addr.takeError();
1043
1044 stack.back().GetScalar() = *maybe_load_addr;
1045 // Fall through to load address promotion code below.
1046 }
1047 [[fallthrough]];
1048 case Value::ValueType::Scalar:
1049 // Promote Scalar to LoadAddress and fall through.
1050 stack.back().SetValueType(Value::ValueType::LoadAddress);
1051 [[fallthrough]];
1052 case Value::ValueType::LoadAddress:
1053 if (exe_ctx) {
1054 if (process) {
1055 lldb::addr_t pointer_addr =
1056 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
1057 Status error;
1058 lldb::addr_t pointer_value =
1059 process->ReadPointerFromMemory(vm_addr: pointer_addr, error);
1060 if (pointer_value != LLDB_INVALID_ADDRESS) {
1061 if (ABISP abi_sp = process->GetABI())
1062 pointer_value = abi_sp->FixCodeAddress(pc: pointer_value);
1063 stack.back().GetScalar() = pointer_value;
1064 stack.back().ClearContext();
1065 } else {
1066 return llvm::createStringError(
1067 Fmt: "Failed to dereference pointer from 0x%" PRIx64
1068 " for DW_OP_deref: %s\n",
1069 Vals: pointer_addr, Vals: error.AsCString());
1070 }
1071 } else {
1072 return llvm::createStringError(Fmt: "NULL process for DW_OP_deref");
1073 }
1074 } else {
1075 return llvm::createStringError(
1076 Fmt: "NULL execution context for DW_OP_deref");
1077 }
1078 break;
1079
1080 case Value::ValueType::Invalid:
1081 return llvm::createStringError(Fmt: "invalid value type for DW_OP_deref");
1082 }
1083
1084 } break;
1085
1086 // OPCODE: DW_OP_deref_size
1087 // OPERANDS: 1
1088 // 1 - uint8_t that specifies the size of the data to dereference.
1089 // DESCRIPTION: Behaves like the DW_OP_deref operation: it pops the top
1090 // stack entry and treats it as an address. The value retrieved from that
1091 // address is pushed. In the DW_OP_deref_size operation, however, the size
1092 // in bytes of the data retrieved from the dereferenced address is
1093 // specified by the single operand. This operand is a 1-byte unsigned
1094 // integral constant whose value may not be larger than the size of an
1095 // address on the target machine. The data retrieved is zero extended to
1096 // the size of an address on the target machine before being pushed on the
1097 // expression stack.
1098 case DW_OP_deref_size: {
1099 if (stack.empty()) {
1100 return llvm::createStringError(
1101 Fmt: "expression stack empty for DW_OP_deref_size");
1102 }
1103 uint8_t size = opcodes.GetU8(offset_ptr: &offset);
1104 if (size > 8) {
1105 return llvm::createStringError(
1106 Fmt: "Invalid address size for DW_OP_deref_size: %d\n", Vals: size);
1107 }
1108 Value::ValueType value_type = stack.back().GetValueType();
1109 switch (value_type) {
1110 case Value::ValueType::HostAddress: {
1111 void *src = (void *)stack.back().GetScalar().ULongLong();
1112 intptr_t ptr;
1113 ::memcpy(dest: &ptr, src: src, n: sizeof(void *));
1114 // I can't decide whether the size operand should apply to the bytes in
1115 // their
1116 // lldb-host endianness or the target endianness.. I doubt this'll ever
1117 // come up but I'll opt for assuming big endian regardless.
1118 switch (size) {
1119 case 1:
1120 ptr = ptr & 0xff;
1121 break;
1122 case 2:
1123 ptr = ptr & 0xffff;
1124 break;
1125 case 3:
1126 ptr = ptr & 0xffffff;
1127 break;
1128 case 4:
1129 ptr = ptr & 0xffffffff;
1130 break;
1131 // the casts are added to work around the case where intptr_t is a 32
1132 // bit quantity;
1133 // presumably we won't hit the 5..7 cases if (void*) is 32-bits in this
1134 // program.
1135 case 5:
1136 ptr = (intptr_t)ptr & 0xffffffffffULL;
1137 break;
1138 case 6:
1139 ptr = (intptr_t)ptr & 0xffffffffffffULL;
1140 break;
1141 case 7:
1142 ptr = (intptr_t)ptr & 0xffffffffffffffULL;
1143 break;
1144 default:
1145 break;
1146 }
1147 stack.back().GetScalar() = ptr;
1148 stack.back().ClearContext();
1149 } break;
1150 case Value::ValueType::FileAddress: {
1151 auto file_addr =
1152 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
1153 Address so_addr;
1154 auto maybe_load_addr = ResolveLoadAddress(
1155 exe_ctx, module_sp, dw_op_type: "DW_OP_deref_size", file_addr, so_addr,
1156 /*check_sectionoffset=*/true);
1157
1158 if (!maybe_load_addr)
1159 return maybe_load_addr.takeError();
1160
1161 addr_t load_addr = *maybe_load_addr;
1162
1163 if (load_addr == LLDB_INVALID_ADDRESS && so_addr.IsSectionOffset()) {
1164 uint8_t addr_bytes[8];
1165 Status error;
1166
1167 if (target &&
1168 target->ReadMemory(addr: so_addr, dst: &addr_bytes, dst_len: size, error,
1169 /*force_live_memory=*/false) == size) {
1170 ObjectFile *objfile = module_sp->GetObjectFile();
1171
1172 stack.back().GetScalar() = DerefSizeExtractDataHelper(
1173 addr_bytes, size_addr_bytes: size, byte_order: objfile->GetByteOrder(), size);
1174 stack.back().ClearContext();
1175 break;
1176 } else {
1177 return llvm::createStringError(
1178 Fmt: "Failed to dereference pointer for DW_OP_deref_size: "
1179 "%s\n",
1180 Vals: error.AsCString());
1181 }
1182 }
1183 stack.back().GetScalar() = load_addr;
1184 // Fall through to load address promotion code below.
1185 }
1186
1187 [[fallthrough]];
1188 case Value::ValueType::Scalar:
1189 case Value::ValueType::LoadAddress:
1190 if (exe_ctx) {
1191 if (process) {
1192 lldb::addr_t pointer_addr =
1193 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
1194 uint8_t addr_bytes[sizeof(lldb::addr_t)];
1195 Status error;
1196 if (process->ReadMemory(vm_addr: pointer_addr, buf: &addr_bytes, size, error) ==
1197 size) {
1198
1199 stack.back().GetScalar() =
1200 DerefSizeExtractDataHelper(addr_bytes, size_addr_bytes: sizeof(addr_bytes),
1201 byte_order: process->GetByteOrder(), size);
1202 stack.back().ClearContext();
1203 } else {
1204 return llvm::createStringError(
1205 Fmt: "Failed to dereference pointer from 0x%" PRIx64
1206 " for DW_OP_deref: %s\n",
1207 Vals: pointer_addr, Vals: error.AsCString());
1208 }
1209 } else {
1210
1211 return llvm::createStringError(Fmt: "NULL process for DW_OP_deref_size");
1212 }
1213 } else {
1214 return llvm::createStringError(
1215 Fmt: "NULL execution context for DW_OP_deref_size");
1216 }
1217 break;
1218
1219 case Value::ValueType::Invalid:
1220
1221 return llvm::createStringError(Fmt: "invalid value for DW_OP_deref_size");
1222 }
1223
1224 } break;
1225
1226 // OPCODE: DW_OP_xderef_size
1227 // OPERANDS: 1
1228 // 1 - uint8_t that specifies the size of the data to dereference.
1229 // DESCRIPTION: Behaves like the DW_OP_xderef operation: the entry at
1230 // the top of the stack is treated as an address. The second stack entry is
1231 // treated as an "address space identifier" for those architectures that
1232 // support multiple address spaces. The top two stack elements are popped,
1233 // a data item is retrieved through an implementation-defined address
1234 // calculation and pushed as the new stack top. In the DW_OP_xderef_size
1235 // operation, however, the size in bytes of the data retrieved from the
1236 // dereferenced address is specified by the single operand. This operand is
1237 // a 1-byte unsigned integral constant whose value may not be larger than
1238 // the size of an address on the target machine. The data retrieved is zero
1239 // extended to the size of an address on the target machine before being
1240 // pushed on the expression stack.
1241 case DW_OP_xderef_size:
1242 return llvm::createStringError(Fmt: "unimplemented opcode: DW_OP_xderef_size");
1243 // OPCODE: DW_OP_xderef
1244 // OPERANDS: none
1245 // DESCRIPTION: Provides an extended dereference mechanism. The entry at
1246 // the top of the stack is treated as an address. The second stack entry is
1247 // treated as an "address space identifier" for those architectures that
1248 // support multiple address spaces. The top two stack elements are popped,
1249 // a data item is retrieved through an implementation-defined address
1250 // calculation and pushed as the new stack top. The size of the data
1251 // retrieved from the dereferenced address is the size of an address on the
1252 // target machine.
1253 case DW_OP_xderef:
1254 return llvm::createStringError(Fmt: "unimplemented opcode: DW_OP_xderef");
1255
1256 // All DW_OP_constXXX opcodes have a single operand as noted below:
1257 //
1258 // Opcode Operand 1
1259 // DW_OP_const1u 1-byte unsigned integer constant
1260 // DW_OP_const1s 1-byte signed integer constant
1261 // DW_OP_const2u 2-byte unsigned integer constant
1262 // DW_OP_const2s 2-byte signed integer constant
1263 // DW_OP_const4u 4-byte unsigned integer constant
1264 // DW_OP_const4s 4-byte signed integer constant
1265 // DW_OP_const8u 8-byte unsigned integer constant
1266 // DW_OP_const8s 8-byte signed integer constant
1267 // DW_OP_constu unsigned LEB128 integer constant
1268 // DW_OP_consts signed LEB128 integer constant
1269 case DW_OP_const1u:
1270 stack.push_back(x: to_generic(opcodes.GetU8(offset_ptr: &offset)));
1271 break;
1272 case DW_OP_const1s:
1273 stack.push_back(x: to_generic((int8_t)opcodes.GetU8(offset_ptr: &offset)));
1274 break;
1275 case DW_OP_const2u:
1276 stack.push_back(x: to_generic(opcodes.GetU16(offset_ptr: &offset)));
1277 break;
1278 case DW_OP_const2s:
1279 stack.push_back(x: to_generic((int16_t)opcodes.GetU16(offset_ptr: &offset)));
1280 break;
1281 case DW_OP_const4u:
1282 stack.push_back(x: to_generic(opcodes.GetU32(offset_ptr: &offset)));
1283 break;
1284 case DW_OP_const4s:
1285 stack.push_back(x: to_generic((int32_t)opcodes.GetU32(offset_ptr: &offset)));
1286 break;
1287 case DW_OP_const8u:
1288 stack.push_back(x: to_generic(opcodes.GetU64(offset_ptr: &offset)));
1289 break;
1290 case DW_OP_const8s:
1291 stack.push_back(x: to_generic((int64_t)opcodes.GetU64(offset_ptr: &offset)));
1292 break;
1293 // These should also use to_generic, but we can't do that due to a
1294 // producer-side bug in llvm. See llvm.org/pr48087.
1295 case DW_OP_constu:
1296 stack.push_back(x: Scalar(opcodes.GetULEB128(offset_ptr: &offset)));
1297 break;
1298 case DW_OP_consts:
1299 stack.push_back(x: Scalar(opcodes.GetSLEB128(offset_ptr: &offset)));
1300 break;
1301
1302 // OPCODE: DW_OP_dup
1303 // OPERANDS: none
1304 // DESCRIPTION: duplicates the value at the top of the stack
1305 case DW_OP_dup:
1306 if (stack.empty()) {
1307 return llvm::createStringError(Fmt: "expression stack empty for DW_OP_dup");
1308 } else
1309 stack.push_back(x: stack.back());
1310 break;
1311
1312 // OPCODE: DW_OP_drop
1313 // OPERANDS: none
1314 // DESCRIPTION: pops the value at the top of the stack
1315 case DW_OP_drop:
1316 if (stack.empty()) {
1317 return llvm::createStringError(Fmt: "expression stack empty for DW_OP_drop");
1318 } else
1319 stack.pop_back();
1320 break;
1321
1322 // OPCODE: DW_OP_over
1323 // OPERANDS: none
1324 // DESCRIPTION: Duplicates the entry currently second in the stack at
1325 // the top of the stack.
1326 case DW_OP_over:
1327 stack.push_back(x: stack[stack.size() - 2]);
1328 break;
1329
1330 // OPCODE: DW_OP_pick
1331 // OPERANDS: uint8_t index into the current stack
1332 // DESCRIPTION: The stack entry with the specified index (0 through 255,
1333 // inclusive) is pushed on the stack
1334 case DW_OP_pick: {
1335 uint8_t pick_idx = opcodes.GetU8(offset_ptr: &offset);
1336 if (pick_idx < stack.size())
1337 stack.push_back(x: stack[stack.size() - 1 - pick_idx]);
1338 else {
1339 return llvm::createStringError(
1340 Fmt: "Index %u out of range for DW_OP_pick.\n", Vals: pick_idx);
1341 }
1342 } break;
1343
1344 // OPCODE: DW_OP_swap
1345 // OPERANDS: none
1346 // DESCRIPTION: swaps the top two stack entries. The entry at the top
1347 // of the stack becomes the second stack entry, and the second entry
1348 // becomes the top of the stack
1349 case DW_OP_swap:
1350 tmp = stack.back();
1351 stack.back() = stack[stack.size() - 2];
1352 stack[stack.size() - 2] = tmp;
1353 break;
1354
1355 // OPCODE: DW_OP_rot
1356 // OPERANDS: none
1357 // DESCRIPTION: Rotates the first three stack entries. The entry at
1358 // the top of the stack becomes the third stack entry, the second entry
1359 // becomes the top of the stack, and the third entry becomes the second
1360 // entry.
1361 case DW_OP_rot: {
1362 size_t last_idx = stack.size() - 1;
1363 Value old_top = stack[last_idx];
1364 stack[last_idx] = stack[last_idx - 1];
1365 stack[last_idx - 1] = stack[last_idx - 2];
1366 stack[last_idx - 2] = old_top;
1367 } break;
1368
1369 // OPCODE: DW_OP_abs
1370 // OPERANDS: none
1371 // DESCRIPTION: pops the top stack entry, interprets it as a signed
1372 // value and pushes its absolute value. If the absolute value can not be
1373 // represented, the result is undefined.
1374 case DW_OP_abs:
1375 if (!stack.back().ResolveValue(exe_ctx).AbsoluteValue()) {
1376 return llvm::createStringError(
1377 Fmt: "failed to take the absolute value of the first stack item");
1378 }
1379 break;
1380
1381 // OPCODE: DW_OP_and
1382 // OPERANDS: none
1383 // DESCRIPTION: pops the top two stack values, performs a bitwise and
1384 // operation on the two, and pushes the result.
1385 case DW_OP_and:
1386 tmp = stack.back();
1387 stack.pop_back();
1388 stack.back().ResolveValue(exe_ctx) =
1389 stack.back().ResolveValue(exe_ctx) & tmp.ResolveValue(exe_ctx);
1390 break;
1391
1392 // OPCODE: DW_OP_div
1393 // OPERANDS: none
1394 // DESCRIPTION: pops the top two stack values, divides the former second
1395 // entry by the former top of the stack using signed division, and pushes
1396 // the result.
1397 case DW_OP_div: {
1398 tmp = stack.back();
1399 if (tmp.ResolveValue(exe_ctx).IsZero())
1400 return llvm::createStringError(Fmt: "divide by zero");
1401
1402 stack.pop_back();
1403 Scalar divisor, dividend;
1404 divisor = tmp.ResolveValue(exe_ctx);
1405 dividend = stack.back().ResolveValue(exe_ctx);
1406 divisor.MakeSigned();
1407 dividend.MakeSigned();
1408 stack.back() = dividend / divisor;
1409
1410 if (!stack.back().ResolveValue(exe_ctx).IsValid())
1411 return llvm::createStringError(Fmt: "divide failed");
1412 } break;
1413
1414 // OPCODE: DW_OP_minus
1415 // OPERANDS: none
1416 // DESCRIPTION: pops the top two stack values, subtracts the former top
1417 // of the stack from the former second entry, and pushes the result.
1418 case DW_OP_minus:
1419 tmp = stack.back();
1420 stack.pop_back();
1421 stack.back().ResolveValue(exe_ctx) =
1422 stack.back().ResolveValue(exe_ctx) - tmp.ResolveValue(exe_ctx);
1423 break;
1424
1425 // OPCODE: DW_OP_mod
1426 // OPERANDS: none
1427 // DESCRIPTION: pops the top two stack values and pushes the result of
1428 // the calculation: former second stack entry modulo the former top of the
1429 // stack.
1430 case DW_OP_mod:
1431 tmp = stack.back();
1432 stack.pop_back();
1433 stack.back().ResolveValue(exe_ctx) =
1434 stack.back().ResolveValue(exe_ctx) % tmp.ResolveValue(exe_ctx);
1435 break;
1436
1437 // OPCODE: DW_OP_mul
1438 // OPERANDS: none
1439 // DESCRIPTION: pops the top two stack entries, multiplies them
1440 // together, and pushes the result.
1441 case DW_OP_mul:
1442 tmp = stack.back();
1443 stack.pop_back();
1444 stack.back().ResolveValue(exe_ctx) =
1445 stack.back().ResolveValue(exe_ctx) * tmp.ResolveValue(exe_ctx);
1446 break;
1447
1448 // OPCODE: DW_OP_neg
1449 // OPERANDS: none
1450 // DESCRIPTION: pops the top stack entry, and pushes its negation.
1451 case DW_OP_neg:
1452 if (!stack.back().ResolveValue(exe_ctx).UnaryNegate())
1453 return llvm::createStringError(Fmt: "unary negate failed");
1454 break;
1455
1456 // OPCODE: DW_OP_not
1457 // OPERANDS: none
1458 // DESCRIPTION: pops the top stack entry, and pushes its bitwise
1459 // complement
1460 case DW_OP_not:
1461 if (!stack.back().ResolveValue(exe_ctx).OnesComplement())
1462 return llvm::createStringError(Fmt: "logical NOT failed");
1463 break;
1464
1465 // OPCODE: DW_OP_or
1466 // OPERANDS: none
1467 // DESCRIPTION: pops the top two stack entries, performs a bitwise or
1468 // operation on the two, and pushes the result.
1469 case DW_OP_or:
1470 tmp = stack.back();
1471 stack.pop_back();
1472 stack.back().ResolveValue(exe_ctx) =
1473 stack.back().ResolveValue(exe_ctx) | tmp.ResolveValue(exe_ctx);
1474 break;
1475
1476 // OPCODE: DW_OP_plus
1477 // OPERANDS: none
1478 // DESCRIPTION: pops the top two stack entries, adds them together, and
1479 // pushes the result.
1480 case DW_OP_plus:
1481 tmp = stack.back();
1482 stack.pop_back();
1483 stack.back().GetScalar() += tmp.GetScalar();
1484 break;
1485
1486 // OPCODE: DW_OP_plus_uconst
1487 // OPERANDS: none
1488 // DESCRIPTION: pops the top stack entry, adds it to the unsigned LEB128
1489 // constant operand and pushes the result.
1490 case DW_OP_plus_uconst: {
1491 const uint64_t uconst_value = opcodes.GetULEB128(offset_ptr: &offset);
1492 // Implicit conversion from a UINT to a Scalar...
1493 stack.back().GetScalar() += uconst_value;
1494 if (!stack.back().GetScalar().IsValid())
1495 return llvm::createStringError(Fmt: "DW_OP_plus_uconst failed");
1496 } break;
1497
1498 // OPCODE: DW_OP_shl
1499 // OPERANDS: none
1500 // DESCRIPTION: pops the top two stack entries, shifts the former
1501 // second entry left by the number of bits specified by the former top of
1502 // the stack, and pushes the result.
1503 case DW_OP_shl:
1504 tmp = stack.back();
1505 stack.pop_back();
1506 stack.back().ResolveValue(exe_ctx) <<= tmp.ResolveValue(exe_ctx);
1507 break;
1508
1509 // OPCODE: DW_OP_shr
1510 // OPERANDS: none
1511 // DESCRIPTION: pops the top two stack entries, shifts the former second
1512 // entry right logically (filling with zero bits) by the number of bits
1513 // specified by the former top of the stack, and pushes the result.
1514 case DW_OP_shr:
1515 tmp = stack.back();
1516 stack.pop_back();
1517 if (!stack.back().ResolveValue(exe_ctx).ShiftRightLogical(
1518 rhs: tmp.ResolveValue(exe_ctx)))
1519 return llvm::createStringError(Fmt: "DW_OP_shr failed");
1520 break;
1521
1522 // OPCODE: DW_OP_shra
1523 // OPERANDS: none
1524 // DESCRIPTION: pops the top two stack entries, shifts the former second
1525 // entry right arithmetically (divide the magnitude by 2, keep the same
1526 // sign for the result) by the number of bits specified by the former top
1527 // of the stack, and pushes the result.
1528 case DW_OP_shra:
1529 tmp = stack.back();
1530 stack.pop_back();
1531 stack.back().ResolveValue(exe_ctx) >>= tmp.ResolveValue(exe_ctx);
1532 break;
1533
1534 // OPCODE: DW_OP_xor
1535 // OPERANDS: none
1536 // DESCRIPTION: pops the top two stack entries, performs the bitwise
1537 // exclusive-or operation on the two, and pushes the result.
1538 case DW_OP_xor:
1539 tmp = stack.back();
1540 stack.pop_back();
1541 stack.back().ResolveValue(exe_ctx) =
1542 stack.back().ResolveValue(exe_ctx) ^ tmp.ResolveValue(exe_ctx);
1543 break;
1544
1545 // OPCODE: DW_OP_skip
1546 // OPERANDS: int16_t
1547 // DESCRIPTION: An unconditional branch. Its single operand is a 2-byte
1548 // signed integer constant. The 2-byte constant is the number of bytes of
1549 // the DWARF expression to skip forward or backward from the current
1550 // operation, beginning after the 2-byte constant.
1551 case DW_OP_skip: {
1552 int16_t skip_offset = (int16_t)opcodes.GetU16(offset_ptr: &offset);
1553 lldb::offset_t new_offset = offset + skip_offset;
1554 // New offset can point at the end of the data, in this case we should
1555 // terminate the DWARF expression evaluation (will happen in the loop
1556 // condition).
1557 if (new_offset <= opcodes.GetByteSize())
1558 offset = new_offset;
1559 else {
1560 return llvm::createStringError(S: llvm::formatv(
1561 Fmt: "Invalid opcode offset in DW_OP_skip: {0}+({1}) > {2}", Vals&: offset,
1562 Vals&: skip_offset, Vals: opcodes.GetByteSize()));
1563 }
1564 } break;
1565
1566 // OPCODE: DW_OP_bra
1567 // OPERANDS: int16_t
1568 // DESCRIPTION: A conditional branch. Its single operand is a 2-byte
1569 // signed integer constant. This operation pops the top of stack. If the
1570 // value popped is not the constant 0, the 2-byte constant operand is the
1571 // number of bytes of the DWARF expression to skip forward or backward from
1572 // the current operation, beginning after the 2-byte constant.
1573 case DW_OP_bra: {
1574 tmp = stack.back();
1575 stack.pop_back();
1576 int16_t bra_offset = (int16_t)opcodes.GetU16(offset_ptr: &offset);
1577 Scalar zero(0);
1578 if (tmp.ResolveValue(exe_ctx) != zero) {
1579 lldb::offset_t new_offset = offset + bra_offset;
1580 // New offset can point at the end of the data, in this case we should
1581 // terminate the DWARF expression evaluation (will happen in the loop
1582 // condition).
1583 if (new_offset <= opcodes.GetByteSize())
1584 offset = new_offset;
1585 else {
1586 return llvm::createStringError(S: llvm::formatv(
1587 Fmt: "Invalid opcode offset in DW_OP_bra: {0}+({1}) > {2}", Vals&: offset,
1588 Vals&: bra_offset, Vals: opcodes.GetByteSize()));
1589 }
1590 }
1591 } break;
1592
1593 // OPCODE: DW_OP_eq
1594 // OPERANDS: none
1595 // DESCRIPTION: pops the top two stack values, compares using the
1596 // equals (==) operator.
1597 // STACK RESULT: push the constant value 1 onto the stack if the result
1598 // of the operation is true or the constant value 0 if the result of the
1599 // operation is false.
1600 case DW_OP_eq:
1601 tmp = stack.back();
1602 stack.pop_back();
1603 stack.back().ResolveValue(exe_ctx) =
1604 stack.back().ResolveValue(exe_ctx) == tmp.ResolveValue(exe_ctx);
1605 break;
1606
1607 // OPCODE: DW_OP_ge
1608 // OPERANDS: none
1609 // DESCRIPTION: pops the top two stack values, compares using the
1610 // greater than or equal to (>=) operator.
1611 // STACK RESULT: push the constant value 1 onto the stack if the result
1612 // of the operation is true or the constant value 0 if the result of the
1613 // operation is false.
1614 case DW_OP_ge:
1615 tmp = stack.back();
1616 stack.pop_back();
1617 stack.back().ResolveValue(exe_ctx) =
1618 stack.back().ResolveValue(exe_ctx) >= tmp.ResolveValue(exe_ctx);
1619 break;
1620
1621 // OPCODE: DW_OP_gt
1622 // OPERANDS: none
1623 // DESCRIPTION: pops the top two stack values, compares using the
1624 // greater than (>) operator.
1625 // STACK RESULT: push the constant value 1 onto the stack if the result
1626 // of the operation is true or the constant value 0 if the result of the
1627 // operation is false.
1628 case DW_OP_gt:
1629 tmp = stack.back();
1630 stack.pop_back();
1631 stack.back().ResolveValue(exe_ctx) =
1632 stack.back().ResolveValue(exe_ctx) > tmp.ResolveValue(exe_ctx);
1633 break;
1634
1635 // OPCODE: DW_OP_le
1636 // OPERANDS: none
1637 // DESCRIPTION: pops the top two stack values, compares using the
1638 // less than or equal to (<=) operator.
1639 // STACK RESULT: push the constant value 1 onto the stack if the result
1640 // of the operation is true or the constant value 0 if the result of the
1641 // operation is false.
1642 case DW_OP_le:
1643 tmp = stack.back();
1644 stack.pop_back();
1645 stack.back().ResolveValue(exe_ctx) =
1646 stack.back().ResolveValue(exe_ctx) <= tmp.ResolveValue(exe_ctx);
1647 break;
1648
1649 // OPCODE: DW_OP_lt
1650 // OPERANDS: none
1651 // DESCRIPTION: pops the top two stack values, compares using the
1652 // less than (<) operator.
1653 // STACK RESULT: push the constant value 1 onto the stack if the result
1654 // of the operation is true or the constant value 0 if the result of the
1655 // operation is false.
1656 case DW_OP_lt:
1657 tmp = stack.back();
1658 stack.pop_back();
1659 stack.back().ResolveValue(exe_ctx) =
1660 stack.back().ResolveValue(exe_ctx) < tmp.ResolveValue(exe_ctx);
1661 break;
1662
1663 // OPCODE: DW_OP_ne
1664 // OPERANDS: none
1665 // DESCRIPTION: pops the top two stack values, compares using the
1666 // not equal (!=) operator.
1667 // STACK RESULT: push the constant value 1 onto the stack if the result
1668 // of the operation is true or the constant value 0 if the result of the
1669 // operation is false.
1670 case DW_OP_ne:
1671 tmp = stack.back();
1672 stack.pop_back();
1673 stack.back().ResolveValue(exe_ctx) =
1674 stack.back().ResolveValue(exe_ctx) != tmp.ResolveValue(exe_ctx);
1675 break;
1676
1677 // OPCODE: DW_OP_litn
1678 // OPERANDS: none
1679 // DESCRIPTION: encode the unsigned literal values from 0 through 31.
1680 // STACK RESULT: push the unsigned literal constant value onto the top
1681 // of the stack.
1682 case DW_OP_lit0:
1683 case DW_OP_lit1:
1684 case DW_OP_lit2:
1685 case DW_OP_lit3:
1686 case DW_OP_lit4:
1687 case DW_OP_lit5:
1688 case DW_OP_lit6:
1689 case DW_OP_lit7:
1690 case DW_OP_lit8:
1691 case DW_OP_lit9:
1692 case DW_OP_lit10:
1693 case DW_OP_lit11:
1694 case DW_OP_lit12:
1695 case DW_OP_lit13:
1696 case DW_OP_lit14:
1697 case DW_OP_lit15:
1698 case DW_OP_lit16:
1699 case DW_OP_lit17:
1700 case DW_OP_lit18:
1701 case DW_OP_lit19:
1702 case DW_OP_lit20:
1703 case DW_OP_lit21:
1704 case DW_OP_lit22:
1705 case DW_OP_lit23:
1706 case DW_OP_lit24:
1707 case DW_OP_lit25:
1708 case DW_OP_lit26:
1709 case DW_OP_lit27:
1710 case DW_OP_lit28:
1711 case DW_OP_lit29:
1712 case DW_OP_lit30:
1713 case DW_OP_lit31:
1714 stack.push_back(x: to_generic(op - DW_OP_lit0));
1715 break;
1716
1717 // OPCODE: DW_OP_regN
1718 // OPERANDS: none
1719 // DESCRIPTION: Push the value in register n on the top of the stack.
1720 case DW_OP_reg0:
1721 case DW_OP_reg1:
1722 case DW_OP_reg2:
1723 case DW_OP_reg3:
1724 case DW_OP_reg4:
1725 case DW_OP_reg5:
1726 case DW_OP_reg6:
1727 case DW_OP_reg7:
1728 case DW_OP_reg8:
1729 case DW_OP_reg9:
1730 case DW_OP_reg10:
1731 case DW_OP_reg11:
1732 case DW_OP_reg12:
1733 case DW_OP_reg13:
1734 case DW_OP_reg14:
1735 case DW_OP_reg15:
1736 case DW_OP_reg16:
1737 case DW_OP_reg17:
1738 case DW_OP_reg18:
1739 case DW_OP_reg19:
1740 case DW_OP_reg20:
1741 case DW_OP_reg21:
1742 case DW_OP_reg22:
1743 case DW_OP_reg23:
1744 case DW_OP_reg24:
1745 case DW_OP_reg25:
1746 case DW_OP_reg26:
1747 case DW_OP_reg27:
1748 case DW_OP_reg28:
1749 case DW_OP_reg29:
1750 case DW_OP_reg30:
1751 case DW_OP_reg31: {
1752 dwarf4_location_description_kind = Register;
1753 reg_num = op - DW_OP_reg0;
1754
1755 if (llvm::Error err =
1756 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, value&: tmp))
1757 return err;
1758 stack.push_back(x: tmp);
1759 } break;
1760 // OPCODE: DW_OP_regx
1761 // OPERANDS:
1762 // ULEB128 literal operand that encodes the register.
1763 // DESCRIPTION: Push the value in register on the top of the stack.
1764 case DW_OP_regx: {
1765 dwarf4_location_description_kind = Register;
1766 reg_num = opcodes.GetULEB128(offset_ptr: &offset);
1767 Status read_err;
1768 if (llvm::Error err =
1769 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, value&: tmp))
1770 return err;
1771 stack.push_back(x: tmp);
1772 } break;
1773
1774 // OPCODE: DW_OP_bregN
1775 // OPERANDS:
1776 // SLEB128 offset from register N
1777 // DESCRIPTION: Value is in memory at the address specified by register
1778 // N plus an offset.
1779 case DW_OP_breg0:
1780 case DW_OP_breg1:
1781 case DW_OP_breg2:
1782 case DW_OP_breg3:
1783 case DW_OP_breg4:
1784 case DW_OP_breg5:
1785 case DW_OP_breg6:
1786 case DW_OP_breg7:
1787 case DW_OP_breg8:
1788 case DW_OP_breg9:
1789 case DW_OP_breg10:
1790 case DW_OP_breg11:
1791 case DW_OP_breg12:
1792 case DW_OP_breg13:
1793 case DW_OP_breg14:
1794 case DW_OP_breg15:
1795 case DW_OP_breg16:
1796 case DW_OP_breg17:
1797 case DW_OP_breg18:
1798 case DW_OP_breg19:
1799 case DW_OP_breg20:
1800 case DW_OP_breg21:
1801 case DW_OP_breg22:
1802 case DW_OP_breg23:
1803 case DW_OP_breg24:
1804 case DW_OP_breg25:
1805 case DW_OP_breg26:
1806 case DW_OP_breg27:
1807 case DW_OP_breg28:
1808 case DW_OP_breg29:
1809 case DW_OP_breg30:
1810 case DW_OP_breg31: {
1811 reg_num = op - DW_OP_breg0;
1812 if (llvm::Error err =
1813 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, value&: tmp))
1814 return err;
1815
1816 int64_t breg_offset = opcodes.GetSLEB128(offset_ptr: &offset);
1817 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset;
1818 tmp.ClearContext();
1819 stack.push_back(x: tmp);
1820 stack.back().SetValueType(Value::ValueType::LoadAddress);
1821 } break;
1822 // OPCODE: DW_OP_bregx
1823 // OPERANDS: 2
1824 // ULEB128 literal operand that encodes the register.
1825 // SLEB128 offset from register N
1826 // DESCRIPTION: Value is in memory at the address specified by register
1827 // N plus an offset.
1828 case DW_OP_bregx: {
1829 reg_num = opcodes.GetULEB128(offset_ptr: &offset);
1830 if (llvm::Error err =
1831 ReadRegisterValueAsScalar(reg_ctx, reg_kind, reg_num, value&: tmp))
1832 return err;
1833
1834 int64_t breg_offset = opcodes.GetSLEB128(offset_ptr: &offset);
1835 tmp.ResolveValue(exe_ctx) += (uint64_t)breg_offset;
1836 tmp.ClearContext();
1837 stack.push_back(x: tmp);
1838 stack.back().SetValueType(Value::ValueType::LoadAddress);
1839 } break;
1840
1841 case DW_OP_fbreg:
1842 if (exe_ctx) {
1843 if (frame) {
1844 Scalar value;
1845 if (llvm::Error err = frame->GetFrameBaseValue(value))
1846 return err;
1847 int64_t fbreg_offset = opcodes.GetSLEB128(offset_ptr: &offset);
1848 value += fbreg_offset;
1849 stack.push_back(x: value);
1850 stack.back().SetValueType(Value::ValueType::LoadAddress);
1851 } else {
1852 return llvm::createStringError(
1853 Fmt: "invalid stack frame in context for DW_OP_fbreg opcode");
1854 }
1855 } else {
1856 return llvm::createStringError(
1857 Fmt: "NULL execution context for DW_OP_fbreg");
1858 }
1859
1860 break;
1861
1862 // OPCODE: DW_OP_nop
1863 // OPERANDS: none
1864 // DESCRIPTION: A place holder. It has no effect on the location stack
1865 // or any of its values.
1866 case DW_OP_nop:
1867 break;
1868
1869 // OPCODE: DW_OP_piece
1870 // OPERANDS: 1
1871 // ULEB128: byte size of the piece
1872 // DESCRIPTION: The operand describes the size in bytes of the piece of
1873 // the object referenced by the DWARF expression whose result is at the top
1874 // of the stack. If the piece is located in a register, but does not occupy
1875 // the entire register, the placement of the piece within that register is
1876 // defined by the ABI.
1877 //
1878 // Many compilers store a single variable in sets of registers, or store a
1879 // variable partially in memory and partially in registers. DW_OP_piece
1880 // provides a way of describing how large a part of a variable a particular
1881 // DWARF expression refers to.
1882 case DW_OP_piece: {
1883 LocationDescriptionKind piece_locdesc = dwarf4_location_description_kind;
1884 // Reset for the next piece.
1885 dwarf4_location_description_kind = Memory;
1886
1887 const uint64_t piece_byte_size = opcodes.GetULEB128(offset_ptr: &offset);
1888
1889 if (piece_byte_size > 0) {
1890 Value curr_piece;
1891
1892 if (stack.empty()) {
1893 UpdateValueTypeFromLocationDescription(
1894 log, dwarf_cu, kind: LocationDescriptionKind::Empty);
1895 // In a multi-piece expression, this means that the current piece is
1896 // not available. Fill with zeros for now by resizing the data and
1897 // appending it
1898 curr_piece.ResizeData(len: piece_byte_size);
1899 // Note that "0" is not a correct value for the unknown bits.
1900 // It would be better to also return a mask of valid bits together
1901 // with the expression result, so the debugger can print missing
1902 // members as "<optimized out>" or something.
1903 ::memset(s: curr_piece.GetBuffer().GetBytes(), c: 0, n: piece_byte_size);
1904 pieces.AppendDataToHostBuffer(rhs: curr_piece);
1905 } else {
1906 Status error;
1907 // Extract the current piece into "curr_piece"
1908 Value curr_piece_source_value(stack.back());
1909 stack.pop_back();
1910 UpdateValueTypeFromLocationDescription(log, dwarf_cu, kind: piece_locdesc,
1911 value: &curr_piece_source_value);
1912
1913 const Value::ValueType curr_piece_source_value_type =
1914 curr_piece_source_value.GetValueType();
1915 Scalar &scalar = curr_piece_source_value.GetScalar();
1916 lldb::addr_t addr = scalar.ULongLong(LLDB_INVALID_ADDRESS);
1917 switch (curr_piece_source_value_type) {
1918 case Value::ValueType::Invalid:
1919 return llvm::createStringError(Fmt: "invalid value type");
1920 case Value::ValueType::FileAddress:
1921 if (target) {
1922 curr_piece_source_value.ConvertToLoadAddress(module: module_sp.get(),
1923 target);
1924 addr = scalar.ULongLong(LLDB_INVALID_ADDRESS);
1925 } else {
1926 return llvm::createStringError(
1927 Fmt: "unable to convert file address 0x%" PRIx64
1928 " to load address "
1929 "for DW_OP_piece(%" PRIu64 "): "
1930 "no target available",
1931 Vals: addr, Vals: piece_byte_size);
1932 }
1933 [[fallthrough]];
1934 case Value::ValueType::LoadAddress: {
1935 if (target) {
1936 if (curr_piece.ResizeData(len: piece_byte_size) == piece_byte_size) {
1937 if (target->ReadMemory(addr, dst: curr_piece.GetBuffer().GetBytes(),
1938 dst_len: piece_byte_size, error,
1939 /*force_live_memory=*/false) !=
1940 piece_byte_size) {
1941 const char *addr_type = (curr_piece_source_value_type ==
1942 Value::ValueType::LoadAddress)
1943 ? "load"
1944 : "file";
1945 return llvm::createStringError(
1946 Fmt: "failed to read memory DW_OP_piece(%" PRIu64
1947 ") from %s address 0x%" PRIx64,
1948 Vals: piece_byte_size, Vals: addr_type, Vals: addr);
1949 }
1950 } else {
1951 return llvm::createStringError(
1952 Fmt: "failed to resize the piece memory buffer for "
1953 "DW_OP_piece(%" PRIu64 ")",
1954 Vals: piece_byte_size);
1955 }
1956 }
1957 } break;
1958 case Value::ValueType::HostAddress: {
1959 return llvm::createStringError(
1960 Fmt: "failed to read memory DW_OP_piece(%" PRIu64
1961 ") from host address 0x%" PRIx64,
1962 Vals: piece_byte_size, Vals: addr);
1963 } break;
1964
1965 case Value::ValueType::Scalar: {
1966 uint32_t bit_size = piece_byte_size * 8;
1967 uint32_t bit_offset = 0;
1968 if (!scalar.ExtractBitfield(
1969 bit_size, bit_offset)) {
1970 return llvm::createStringError(
1971 Fmt: "unable to extract %" PRIu64 " bytes from a %" PRIu64
1972 " byte scalar value.",
1973 Vals: piece_byte_size,
1974 Vals: (uint64_t)curr_piece_source_value.GetScalar().GetByteSize());
1975 }
1976 // Create curr_piece with bit_size. By default Scalar
1977 // grows to the nearest host integer type.
1978 llvm::APInt fail_value(1, 0, false);
1979 llvm::APInt ap_int = scalar.UInt128(fail_value);
1980 assert(ap_int.getBitWidth() >= bit_size);
1981 llvm::ArrayRef<uint64_t> buf{ap_int.getRawData(),
1982 ap_int.getNumWords()};
1983 curr_piece.GetScalar() = Scalar(llvm::APInt(bit_size, buf));
1984 } break;
1985 }
1986
1987 // Check if this is the first piece?
1988 if (op_piece_offset == 0) {
1989 // This is the first piece, we should push it back onto the stack
1990 // so subsequent pieces will be able to access this piece and add
1991 // to it.
1992 if (pieces.AppendDataToHostBuffer(rhs: curr_piece) == 0) {
1993 return llvm::createStringError(Fmt: "failed to append piece data");
1994 }
1995 } else {
1996 // If this is the second or later piece there should be a value on
1997 // the stack.
1998 if (pieces.GetBuffer().GetByteSize() != op_piece_offset) {
1999 return llvm::createStringError(
2000 Fmt: "DW_OP_piece for offset %" PRIu64
2001 " but top of stack is of size %" PRIu64,
2002 Vals: op_piece_offset, Vals: pieces.GetBuffer().GetByteSize());
2003 }
2004
2005 if (pieces.AppendDataToHostBuffer(rhs: curr_piece) == 0)
2006 return llvm::createStringError(Fmt: "failed to append piece data");
2007 }
2008 }
2009 op_piece_offset += piece_byte_size;
2010 }
2011 } break;
2012
2013 case DW_OP_bit_piece: // 0x9d ULEB128 bit size, ULEB128 bit offset (DWARF3);
2014 if (stack.size() < 1) {
2015 UpdateValueTypeFromLocationDescription(log, dwarf_cu,
2016 kind: LocationDescriptionKind::Empty);
2017 // Reset for the next piece.
2018 dwarf4_location_description_kind = Memory;
2019 return llvm::createStringError(
2020 Fmt: "expression stack needs at least 1 item for DW_OP_bit_piece");
2021 } else {
2022 UpdateValueTypeFromLocationDescription(
2023 log, dwarf_cu, kind: dwarf4_location_description_kind, value: &stack.back());
2024 // Reset for the next piece.
2025 dwarf4_location_description_kind = Memory;
2026 const uint64_t piece_bit_size = opcodes.GetULEB128(offset_ptr: &offset);
2027 const uint64_t piece_bit_offset = opcodes.GetULEB128(offset_ptr: &offset);
2028 switch (stack.back().GetValueType()) {
2029 case Value::ValueType::Invalid:
2030 return llvm::createStringError(
2031 Fmt: "unable to extract bit value from invalid value");
2032 case Value::ValueType::Scalar: {
2033 if (!stack.back().GetScalar().ExtractBitfield(bit_size: piece_bit_size,
2034 bit_offset: piece_bit_offset)) {
2035 return llvm::createStringError(
2036 Fmt: "unable to extract %" PRIu64 " bit value with %" PRIu64
2037 " bit offset from a %" PRIu64 " bit scalar value.",
2038 Vals: piece_bit_size, Vals: piece_bit_offset,
2039 Vals: (uint64_t)(stack.back().GetScalar().GetByteSize() * 8));
2040 }
2041 } break;
2042
2043 case Value::ValueType::FileAddress:
2044 case Value::ValueType::LoadAddress:
2045 case Value::ValueType::HostAddress:
2046 return llvm::createStringError(
2047 Fmt: "unable to extract DW_OP_bit_piece(bit_size = %" PRIu64
2048 ", bit_offset = %" PRIu64 ") from an address value.",
2049 Vals: piece_bit_size, Vals: piece_bit_offset);
2050 }
2051 }
2052 break;
2053
2054 // OPCODE: DW_OP_implicit_value
2055 // OPERANDS: 2
2056 // ULEB128 size of the value block in bytes
2057 // uint8_t* block bytes encoding value in target's memory
2058 // representation
2059 // DESCRIPTION: Value is immediately stored in block in the debug info with
2060 // the memory representation of the target.
2061 case DW_OP_implicit_value: {
2062 dwarf4_location_description_kind = Implicit;
2063
2064 const uint32_t len = opcodes.GetULEB128(offset_ptr: &offset);
2065 const void *data = opcodes.GetData(offset_ptr: &offset, length: len);
2066
2067 if (!data) {
2068 LLDB_LOG(log, "Evaluate_DW_OP_implicit_value: could not be read data");
2069 return llvm::createStringError(Fmt: "could not evaluate %s",
2070 Vals: DW_OP_value_to_name(val: op));
2071 }
2072
2073 Value result(data, len);
2074 stack.push_back(x: result);
2075 break;
2076 }
2077
2078 case DW_OP_implicit_pointer: {
2079 dwarf4_location_description_kind = Implicit;
2080 return llvm::createStringError(Fmt: "Could not evaluate %s.",
2081 Vals: DW_OP_value_to_name(val: op));
2082 }
2083
2084 // OPCODE: DW_OP_push_object_address
2085 // OPERANDS: none
2086 // DESCRIPTION: Pushes the address of the object currently being
2087 // evaluated as part of evaluation of a user presented expression. This
2088 // object may correspond to an independent variable described by its own
2089 // DIE or it may be a component of an array, structure, or class whose
2090 // address has been dynamically determined by an earlier step during user
2091 // expression evaluation.
2092 case DW_OP_push_object_address:
2093 if (object_address_ptr)
2094 stack.push_back(x: *object_address_ptr);
2095 else {
2096 return llvm::createStringError(Fmt: "DW_OP_push_object_address used without "
2097 "specifying an object address");
2098 }
2099 break;
2100
2101 // OPCODE: DW_OP_call2
2102 // OPERANDS:
2103 // uint16_t compile unit relative offset of a DIE
2104 // DESCRIPTION: Performs subroutine calls during evaluation
2105 // of a DWARF expression. The operand is the 2-byte unsigned offset of a
2106 // debugging information entry in the current compilation unit.
2107 //
2108 // Operand interpretation is exactly like that for DW_FORM_ref2.
2109 //
2110 // This operation transfers control of DWARF expression evaluation to the
2111 // DW_AT_location attribute of the referenced DIE. If there is no such
2112 // attribute, then there is no effect. Execution of the DWARF expression of
2113 // a DW_AT_location attribute may add to and/or remove from values on the
2114 // stack. Execution returns to the point following the call when the end of
2115 // the attribute is reached. Values on the stack at the time of the call
2116 // may be used as parameters by the called expression and values left on
2117 // the stack by the called expression may be used as return values by prior
2118 // agreement between the calling and called expressions.
2119 case DW_OP_call2:
2120 return llvm::createStringError(Fmt: "unimplemented opcode DW_OP_call2");
2121 // OPCODE: DW_OP_call4
2122 // OPERANDS: 1
2123 // uint32_t compile unit relative offset of a DIE
2124 // DESCRIPTION: Performs a subroutine call during evaluation of a DWARF
2125 // expression. For DW_OP_call4, the operand is a 4-byte unsigned offset of
2126 // a debugging information entry in the current compilation unit.
2127 //
2128 // Operand interpretation DW_OP_call4 is exactly like that for
2129 // DW_FORM_ref4.
2130 //
2131 // This operation transfers control of DWARF expression evaluation to the
2132 // DW_AT_location attribute of the referenced DIE. If there is no such
2133 // attribute, then there is no effect. Execution of the DWARF expression of
2134 // a DW_AT_location attribute may add to and/or remove from values on the
2135 // stack. Execution returns to the point following the call when the end of
2136 // the attribute is reached. Values on the stack at the time of the call
2137 // may be used as parameters by the called expression and values left on
2138 // the stack by the called expression may be used as return values by prior
2139 // agreement between the calling and called expressions.
2140 case DW_OP_call4:
2141 return llvm::createStringError(Fmt: "unimplemented opcode DW_OP_call4");
2142
2143 // OPCODE: DW_OP_stack_value
2144 // OPERANDS: None
2145 // DESCRIPTION: Specifies that the object does not exist in memory but
2146 // rather is a constant value. The value from the top of the stack is the
2147 // value to be used. This is the actual object value and not the location.
2148 case DW_OP_stack_value:
2149 dwarf4_location_description_kind = Implicit;
2150 stack.back().SetValueType(Value::ValueType::Scalar);
2151 break;
2152
2153 // OPCODE: DW_OP_convert
2154 // OPERANDS: 1
2155 // A ULEB128 that is either a DIE offset of a
2156 // DW_TAG_base_type or 0 for the generic (pointer-sized) type.
2157 //
2158 // DESCRIPTION: Pop the top stack element, convert it to a
2159 // different type, and push the result.
2160 case DW_OP_convert: {
2161 const uint64_t relative_die_offset = opcodes.GetULEB128(offset_ptr: &offset);
2162 uint64_t bit_size;
2163 bool sign;
2164 if (relative_die_offset == 0) {
2165 // The generic type has the size of an address on the target
2166 // machine and an unspecified signedness. Scalar has no
2167 // "unspecified signedness", so we use unsigned types.
2168 if (!module_sp)
2169 return llvm::createStringError(Fmt: "no module");
2170 sign = false;
2171 bit_size = module_sp->GetArchitecture().GetAddressByteSize() * 8;
2172 if (!bit_size)
2173 return llvm::createStringError(Fmt: "unspecified architecture");
2174 } else {
2175 auto bit_size_sign_or_err =
2176 dwarf_cu->GetDIEBitSizeAndSign(relative_die_offset);
2177 if (!bit_size_sign_or_err)
2178 return bit_size_sign_or_err.takeError();
2179 bit_size = bit_size_sign_or_err->first;
2180 sign = bit_size_sign_or_err->second;
2181 }
2182 Scalar &top = stack.back().ResolveValue(exe_ctx);
2183 top.TruncOrExtendTo(bits: bit_size, sign);
2184 break;
2185 }
2186
2187 // OPCODE: DW_OP_call_frame_cfa
2188 // OPERANDS: None
2189 // DESCRIPTION: Specifies a DWARF expression that pushes the value of
2190 // the canonical frame address consistent with the call frame information
2191 // located in .debug_frame (or in the FDEs of the eh_frame section).
2192 case DW_OP_call_frame_cfa:
2193 if (frame) {
2194 // Note that we don't have to parse FDEs because this DWARF expression
2195 // is commonly evaluated with a valid stack frame.
2196 StackID id = frame->GetStackID();
2197 addr_t cfa = id.GetCallFrameAddress();
2198 if (cfa != LLDB_INVALID_ADDRESS) {
2199 stack.push_back(x: Scalar(cfa));
2200 stack.back().SetValueType(Value::ValueType::LoadAddress);
2201 } else {
2202 return llvm::createStringError(
2203 Fmt: "stack frame does not include a canonical "
2204 "frame address for DW_OP_call_frame_cfa "
2205 "opcode");
2206 }
2207 } else {
2208 return llvm::createStringError(Fmt: "unvalid stack frame in context for "
2209 "DW_OP_call_frame_cfa opcode");
2210 }
2211 break;
2212
2213 // OPCODE: DW_OP_form_tls_address (or the old pre-DWARFv3 vendor extension
2214 // opcode, DW_OP_GNU_push_tls_address)
2215 // OPERANDS: none
2216 // DESCRIPTION: Pops a TLS offset from the stack, converts it to
2217 // an address in the current thread's thread-local storage block, and
2218 // pushes it on the stack.
2219 case DW_OP_form_tls_address:
2220 case DW_OP_GNU_push_tls_address: {
2221 if (stack.size() < 1) {
2222 if (op == DW_OP_form_tls_address)
2223 return llvm::createStringError(
2224 Fmt: "DW_OP_form_tls_address needs an argument");
2225 else
2226 return llvm::createStringError(
2227 Fmt: "DW_OP_GNU_push_tls_address needs an argument");
2228 }
2229
2230 if (!exe_ctx || !module_sp)
2231 return llvm::createStringError(Fmt: "no context to evaluate TLS within");
2232
2233 Thread *thread = exe_ctx->GetThreadPtr();
2234 if (!thread)
2235 return llvm::createStringError(Fmt: "no thread to evaluate TLS within");
2236
2237 // Lookup the TLS block address for this thread and module.
2238 const addr_t tls_file_addr =
2239 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
2240 const addr_t tls_load_addr =
2241 thread->GetThreadLocalData(module: module_sp, tls_file_addr);
2242
2243 if (tls_load_addr == LLDB_INVALID_ADDRESS)
2244 return llvm::createStringError(
2245 Fmt: "no TLS data currently exists for this thread");
2246
2247 stack.back().GetScalar() = tls_load_addr;
2248 stack.back().SetValueType(Value::ValueType::LoadAddress);
2249 } break;
2250
2251 // OPCODE: DW_OP_addrx (DW_OP_GNU_addr_index is the legacy name.)
2252 // OPERANDS: 1
2253 // ULEB128: index to the .debug_addr section
2254 // DESCRIPTION: Pushes an address to the stack from the .debug_addr
2255 // section with the base address specified by the DW_AT_addr_base attribute
2256 // and the 0 based index is the ULEB128 encoded index.
2257 case DW_OP_addrx:
2258 case DW_OP_GNU_addr_index: {
2259 if (!dwarf_cu)
2260 return llvm::createStringError(Fmt: "DW_OP_GNU_addr_index found without a "
2261 "compile unit being specified");
2262 uint64_t index = opcodes.GetULEB128(offset_ptr: &offset);
2263 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index);
2264 stack.push_back(x: Scalar(value));
2265 if (target &&
2266 target->GetArchitecture().GetCore() == ArchSpec::eCore_wasm32) {
2267 // wasm file sections aren't mapped into memory, therefore addresses can
2268 // never point into a file section and are always LoadAddresses.
2269 stack.back().SetValueType(Value::ValueType::LoadAddress);
2270 } else {
2271 stack.back().SetValueType(Value::ValueType::FileAddress);
2272 }
2273 } break;
2274
2275 // OPCODE: DW_OP_GNU_const_index
2276 // OPERANDS: 1
2277 // ULEB128: index to the .debug_addr section
2278 // DESCRIPTION: Pushes an constant with the size of a machine address to
2279 // the stack from the .debug_addr section with the base address specified
2280 // by the DW_AT_addr_base attribute and the 0 based index is the ULEB128
2281 // encoded index.
2282 case DW_OP_GNU_const_index: {
2283 if (!dwarf_cu) {
2284 return llvm::createStringError(Fmt: "DW_OP_GNU_const_index found without a "
2285 "compile unit being specified");
2286 }
2287 uint64_t index = opcodes.GetULEB128(offset_ptr: &offset);
2288 lldb::addr_t value = dwarf_cu->ReadAddressFromDebugAddrSection(index);
2289 stack.push_back(x: Scalar(value));
2290 } break;
2291
2292 case DW_OP_GNU_entry_value:
2293 case DW_OP_entry_value: {
2294 if (llvm::Error err = Evaluate_DW_OP_entry_value(stack, exe_ctx, reg_ctx,
2295 opcodes, opcode_offset&: offset, log))
2296 return llvm::createStringError(
2297 Fmt: "could not evaluate DW_OP_entry_value: %s",
2298 Vals: llvm::toString(E: std::move(err)).c_str());
2299 break;
2300 }
2301
2302 default:
2303 if (dwarf_cu) {
2304 if (dwarf_cu->ParseVendorDWARFOpcode(op, opcodes, offset, stack)) {
2305 break;
2306 }
2307 }
2308 return llvm::createStringError(S: llvm::formatv(
2309 Fmt: "Unhandled opcode {0} in DWARFExpression", Vals: LocationAtom(op)));
2310 }
2311 }
2312
2313 if (stack.empty()) {
2314 // Nothing on the stack, check if we created a piece value from DW_OP_piece
2315 // or DW_OP_bit_piece opcodes
2316 if (pieces.GetBuffer().GetByteSize())
2317 return pieces;
2318
2319 return llvm::createStringError(Fmt: "stack empty after evaluation");
2320 }
2321
2322 UpdateValueTypeFromLocationDescription(
2323 log, dwarf_cu, kind: dwarf4_location_description_kind, value: &stack.back());
2324
2325 if (log && log->GetVerbose()) {
2326 size_t count = stack.size();
2327 LLDB_LOGF(log,
2328 "Stack after operation has %" PRIu64 " values:", (uint64_t)count);
2329 for (size_t i = 0; i < count; ++i) {
2330 StreamString new_value;
2331 new_value.Printf(format: "[%" PRIu64 "]", (uint64_t)i);
2332 stack[i].Dump(strm: &new_value);
2333 LLDB_LOGF(log, " %s", new_value.GetData());
2334 }
2335 }
2336 return stack.back();
2337}
2338
2339bool DWARFExpression::MatchesOperand(
2340 StackFrame &frame, const Instruction::Operand &operand) const {
2341 using namespace OperandMatchers;
2342
2343 RegisterContextSP reg_ctx_sp = frame.GetRegisterContext();
2344 if (!reg_ctx_sp) {
2345 return false;
2346 }
2347
2348 DataExtractor opcodes(m_data);
2349
2350 lldb::offset_t op_offset = 0;
2351 uint8_t opcode = opcodes.GetU8(offset_ptr: &op_offset);
2352
2353 if (opcode == DW_OP_fbreg) {
2354 int64_t offset = opcodes.GetSLEB128(offset_ptr: &op_offset);
2355
2356 DWARFExpressionList *fb_expr = frame.GetFrameBaseExpression(error_ptr: nullptr);
2357 if (!fb_expr) {
2358 return false;
2359 }
2360
2361 auto recurse = [&frame, fb_expr](const Instruction::Operand &child) {
2362 return fb_expr->MatchesOperand(frame, operand: child);
2363 };
2364
2365 if (!offset &&
2366 MatchUnaryOp(base: MatchOpType(type: Instruction::Operand::Type::Dereference),
2367 child: recurse)(operand)) {
2368 return true;
2369 }
2370
2371 return MatchUnaryOp(
2372 base: MatchOpType(type: Instruction::Operand::Type::Dereference),
2373 child: MatchBinaryOp(base: MatchOpType(type: Instruction::Operand::Type::Sum),
2374 left: MatchImmOp(imm: offset), right: recurse))(operand);
2375 }
2376
2377 bool dereference = false;
2378 const RegisterInfo *reg = nullptr;
2379 int64_t offset = 0;
2380
2381 if (opcode >= DW_OP_reg0 && opcode <= DW_OP_reg31) {
2382 reg = reg_ctx_sp->GetRegisterInfo(reg_kind: m_reg_kind, reg_num: opcode - DW_OP_reg0);
2383 } else if (opcode >= DW_OP_breg0 && opcode <= DW_OP_breg31) {
2384 offset = opcodes.GetSLEB128(offset_ptr: &op_offset);
2385 reg = reg_ctx_sp->GetRegisterInfo(reg_kind: m_reg_kind, reg_num: opcode - DW_OP_breg0);
2386 } else if (opcode == DW_OP_regx) {
2387 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(offset_ptr: &op_offset));
2388 reg = reg_ctx_sp->GetRegisterInfo(reg_kind: m_reg_kind, reg_num);
2389 } else if (opcode == DW_OP_bregx) {
2390 uint32_t reg_num = static_cast<uint32_t>(opcodes.GetULEB128(offset_ptr: &op_offset));
2391 offset = opcodes.GetSLEB128(offset_ptr: &op_offset);
2392 reg = reg_ctx_sp->GetRegisterInfo(reg_kind: m_reg_kind, reg_num);
2393 } else {
2394 return false;
2395 }
2396
2397 if (!reg) {
2398 return false;
2399 }
2400
2401 if (dereference) {
2402 if (!offset &&
2403 MatchUnaryOp(base: MatchOpType(type: Instruction::Operand::Type::Dereference),
2404 child: MatchRegOp(info: *reg))(operand)) {
2405 return true;
2406 }
2407
2408 return MatchUnaryOp(
2409 base: MatchOpType(type: Instruction::Operand::Type::Dereference),
2410 child: MatchBinaryOp(base: MatchOpType(type: Instruction::Operand::Type::Sum),
2411 left: MatchRegOp(info: *reg),
2412 right: MatchImmOp(imm: offset)))(operand);
2413 } else {
2414 return MatchRegOp(info: *reg)(operand);
2415 }
2416}
2417

Provided by KDAB

Privacy Policy
Update your C++ knowledge – Modern C++11/14/17 Training
Find out more

source code of lldb/source/Expression/DWARFExpression.cpp