Line data Source code
1 : // Copyright 2011 the V8 project authors. All rights reserved.
2 : // Use of this source code is governed by a BSD-style license that can be
3 : // found in the LICENSE file.
4 :
5 : #include "src/disassembler.h"
6 :
7 : #include <memory>
8 : #include <unordered_map>
9 : #include <vector>
10 :
11 : #include "src/assembler-inl.h"
12 : #include "src/code-comments.h"
13 : #include "src/code-reference.h"
14 : #include "src/debug/debug.h"
15 : #include "src/deoptimizer.h"
16 : #include "src/disasm.h"
17 : #include "src/ic/ic.h"
18 : #include "src/isolate-data.h"
19 : #include "src/macro-assembler.h"
20 : #include "src/objects-inl.h"
21 : #include "src/snapshot/embedded-data.h"
22 : #include "src/snapshot/serializer-common.h"
23 : #include "src/string-stream.h"
24 : #include "src/vector.h"
25 : #include "src/wasm/wasm-code-manager.h"
26 : #include "src/wasm/wasm-engine.h"
27 :
28 : namespace v8 {
29 : namespace internal {
30 :
31 : #ifdef ENABLE_DISASSEMBLER
32 :
33 : class V8NameConverter: public disasm::NameConverter {
34 : public:
35 : explicit V8NameConverter(Isolate* isolate, CodeReference code = {})
36 : : isolate_(isolate), code_(code) {}
37 : const char* NameOfAddress(byte* pc) const override;
38 : const char* NameInCode(byte* addr) const override;
39 : const char* RootRelativeName(int offset) const override;
40 :
41 : const CodeReference& code() const { return code_; }
42 :
43 : private:
44 : void InitExternalRefsCache() const;
45 :
46 : Isolate* isolate_;
47 : CodeReference code_;
48 :
49 : EmbeddedVector<char, 128> v8_buffer_;
50 :
51 : // Map from root-register relative offset of the external reference value to
52 : // the external reference name (stored in the external reference table).
53 : // This cache is used to recognize [root_reg + offs] patterns as direct
54 : // access to certain external reference's value.
55 : mutable std::unordered_map<int, const char*> directly_accessed_external_refs_;
56 : };
57 :
58 : void V8NameConverter::InitExternalRefsCache() const {
59 : ExternalReferenceTable* external_reference_table =
60 : isolate_->external_reference_table();
61 : if (!external_reference_table->is_initialized()) return;
62 :
63 : base::AddressRegion addressable_region =
64 : isolate_->root_register_addressable_region();
65 : Address isolate_root = isolate_->isolate_root();
66 :
67 : for (uint32_t i = 0; i < ExternalReferenceTable::kSize; i++) {
68 : Address address = external_reference_table->address(i);
69 : if (addressable_region.contains(address)) {
70 : int offset = static_cast<int>(address - isolate_root);
71 : const char* name = external_reference_table->name(i);
72 : directly_accessed_external_refs_.insert({offset, name});
73 : }
74 : }
75 : }
76 :
77 : const char* V8NameConverter::NameOfAddress(byte* pc) const {
78 : if (!code_.is_null()) {
79 : const char* name =
80 : isolate_ ? isolate_->builtins()->Lookup(reinterpret_cast<Address>(pc))
81 : : nullptr;
82 :
83 : if (name != nullptr) {
84 : SNPrintF(v8_buffer_, "%p (%s)", static_cast<void*>(pc), name);
85 : return v8_buffer_.start();
86 : }
87 :
88 : int offs = static_cast<int>(reinterpret_cast<Address>(pc) -
89 : code_.instruction_start());
90 : // print as code offset, if it seems reasonable
91 : if (0 <= offs && offs < code_.instruction_size()) {
92 : SNPrintF(v8_buffer_, "%p <+0x%x>", static_cast<void*>(pc), offs);
93 : return v8_buffer_.start();
94 : }
95 :
96 : wasm::WasmCode* wasm_code =
97 : isolate_ ? isolate_->wasm_engine()->code_manager()->LookupCode(
98 : reinterpret_cast<Address>(pc))
99 : : nullptr;
100 : if (wasm_code != nullptr) {
101 : SNPrintF(v8_buffer_, "%p (%s)", static_cast<void*>(pc),
102 : wasm::GetWasmCodeKindAsString(wasm_code->kind()));
103 : return v8_buffer_.start();
104 : }
105 : }
106 :
107 : return disasm::NameConverter::NameOfAddress(pc);
108 : }
109 :
110 :
111 : const char* V8NameConverter::NameInCode(byte* addr) const {
112 : // The V8NameConverter is used for well known code, so we can "safely"
113 : // dereference pointers in generated code.
114 : return code_.is_null() ? "" : reinterpret_cast<const char*>(addr);
115 : }
116 :
117 : const char* V8NameConverter::RootRelativeName(int offset) const {
118 : if (isolate_ == nullptr) return nullptr;
119 :
120 : const int kRootsTableStart = IsolateData::roots_table_offset();
121 : const unsigned kRootsTableSize = sizeof(RootsTable);
122 : const int kExtRefsTableStart = IsolateData::external_reference_table_offset();
123 : const unsigned kExtRefsTableSize = ExternalReferenceTable::kSizeInBytes;
124 : const int kBuiltinsTableStart = IsolateData::builtins_table_offset();
125 : const unsigned kBuiltinsTableSize =
126 : Builtins::builtin_count * kSystemPointerSize;
127 :
128 : if (static_cast<unsigned>(offset - kRootsTableStart) < kRootsTableSize) {
129 : uint32_t offset_in_roots_table = offset - kRootsTableStart;
130 :
131 : // Fail safe in the unlikely case of an arbitrary root-relative offset.
132 : if (offset_in_roots_table % kSystemPointerSize != 0) return nullptr;
133 :
134 : RootIndex root_index =
135 : static_cast<RootIndex>(offset_in_roots_table / kSystemPointerSize);
136 :
137 : SNPrintF(v8_buffer_, "root (%s)", RootsTable::name(root_index));
138 : return v8_buffer_.start();
139 :
140 : } else if (static_cast<unsigned>(offset - kExtRefsTableStart) <
141 : kExtRefsTableSize) {
142 : uint32_t offset_in_extref_table = offset - kExtRefsTableStart;
143 :
144 : // Fail safe in the unlikely case of an arbitrary root-relative offset.
145 : if (offset_in_extref_table % ExternalReferenceTable::kEntrySize != 0) {
146 : return nullptr;
147 : }
148 :
149 : // Likewise if the external reference table is uninitialized.
150 : if (!isolate_->external_reference_table()->is_initialized()) {
151 : return nullptr;
152 : }
153 :
154 : SNPrintF(v8_buffer_, "external reference (%s)",
155 : isolate_->external_reference_table()->NameFromOffset(
156 : offset_in_extref_table));
157 : return v8_buffer_.start();
158 :
159 : } else if (static_cast<unsigned>(offset - kBuiltinsTableStart) <
160 : kBuiltinsTableSize) {
161 : uint32_t offset_in_builtins_table = (offset - kBuiltinsTableStart);
162 :
163 : Builtins::Name builtin_id = static_cast<Builtins::Name>(
164 : offset_in_builtins_table / kSystemPointerSize);
165 :
166 : const char* name = Builtins::name(builtin_id);
167 : SNPrintF(v8_buffer_, "builtin (%s)", name);
168 : return v8_buffer_.start();
169 :
170 : } else {
171 : // It must be a direct access to one of the external values.
172 : if (directly_accessed_external_refs_.empty()) {
173 : InitExternalRefsCache();
174 : }
175 :
176 : auto iter = directly_accessed_external_refs_.find(offset);
177 : if (iter != directly_accessed_external_refs_.end()) {
178 : SNPrintF(v8_buffer_, "external value (%s)", iter->second);
179 : return v8_buffer_.start();
180 : }
181 : return "WAAT??? What are we accessing here???";
182 : }
183 : }
184 :
185 : static void DumpBuffer(std::ostream* os, StringBuilder* out) {
186 : (*os) << out->Finalize() << std::endl;
187 : out->Reset();
188 : }
189 :
190 :
191 : static const int kOutBufferSize = 2048 + String::kMaxShortPrintLength;
192 : static const int kRelocInfoPosition = 57;
193 :
194 : static void PrintRelocInfo(StringBuilder* out, Isolate* isolate,
195 : const ExternalReferenceEncoder* ref_encoder,
196 : std::ostream* os, CodeReference host,
197 : RelocInfo* relocinfo, bool first_reloc_info = true) {
198 : // Indent the printing of the reloc info.
199 : if (first_reloc_info) {
200 : // The first reloc info is printed after the disassembled instruction.
201 : out->AddPadding(' ', kRelocInfoPosition - out->position());
202 : } else {
203 : // Additional reloc infos are printed on separate lines.
204 : DumpBuffer(os, out);
205 : out->AddPadding(' ', kRelocInfoPosition);
206 : }
207 :
208 : RelocInfo::Mode rmode = relocinfo->rmode();
209 : if (rmode == RelocInfo::DEOPT_SCRIPT_OFFSET) {
210 : out->AddFormatted(" ;; debug: deopt position, script offset '%d'",
211 : static_cast<int>(relocinfo->data()));
212 : } else if (rmode == RelocInfo::DEOPT_INLINING_ID) {
213 : out->AddFormatted(" ;; debug: deopt position, inlining id '%d'",
214 : static_cast<int>(relocinfo->data()));
215 : } else if (rmode == RelocInfo::DEOPT_REASON) {
216 : DeoptimizeReason reason = static_cast<DeoptimizeReason>(relocinfo->data());
217 : out->AddFormatted(" ;; debug: deopt reason '%s'",
218 : DeoptimizeReasonToString(reason));
219 : } else if (rmode == RelocInfo::DEOPT_ID) {
220 : out->AddFormatted(" ;; debug: deopt index %d",
221 : static_cast<int>(relocinfo->data()));
222 : } else if (rmode == RelocInfo::EMBEDDED_OBJECT) {
223 : HeapStringAllocator allocator;
224 : StringStream accumulator(&allocator);
225 : relocinfo->target_object()->ShortPrint(&accumulator);
226 : std::unique_ptr<char[]> obj_name = accumulator.ToCString();
227 : out->AddFormatted(" ;; object: %s", obj_name.get());
228 : } else if (rmode == RelocInfo::EXTERNAL_REFERENCE) {
229 : const char* reference_name =
230 : ref_encoder ? ref_encoder->NameOfAddress(
231 : isolate, relocinfo->target_external_reference())
232 : : "unknown";
233 : out->AddFormatted(" ;; external reference (%s)", reference_name);
234 : } else if (RelocInfo::IsCodeTargetMode(rmode)) {
235 : out->AddFormatted(" ;; code:");
236 : Code code = isolate->heap()->GcSafeFindCodeForInnerPointer(
237 : relocinfo->target_address());
238 : Code::Kind kind = code->kind();
239 : if (code->is_builtin()) {
240 : out->AddFormatted(" Builtin::%s", Builtins::name(code->builtin_index()));
241 : } else {
242 : out->AddFormatted(" %s", Code::Kind2String(kind));
243 : }
244 : } else if (RelocInfo::IsWasmStubCall(rmode) && host.is_wasm_code()) {
245 : // Host is isolate-independent, try wasm native module instead.
246 : const char* runtime_stub_name =
247 : host.as_wasm_code()->native_module()->GetRuntimeStubName(
248 : relocinfo->wasm_stub_call_address());
249 : out->AddFormatted(" ;; wasm stub: %s", runtime_stub_name);
250 : } else if (RelocInfo::IsRuntimeEntry(rmode) && isolate &&
251 : isolate->deoptimizer_data() != nullptr) {
252 : // A runtime entry relocinfo might be a deoptimization bailout.
253 : Address addr = relocinfo->target_address();
254 : DeoptimizeKind type;
255 : if (Deoptimizer::IsDeoptimizationEntry(isolate, addr, &type)) {
256 : out->AddFormatted(" ;; %s deoptimization bailout",
257 : Deoptimizer::MessageFor(type));
258 : } else {
259 : out->AddFormatted(" ;; %s", RelocInfo::RelocModeName(rmode));
260 : }
261 : } else {
262 : out->AddFormatted(" ;; %s", RelocInfo::RelocModeName(rmode));
263 : }
264 : }
265 :
266 : static int DecodeIt(Isolate* isolate, ExternalReferenceEncoder* ref_encoder,
267 : std::ostream* os, CodeReference code,
268 : const V8NameConverter& converter, byte* begin, byte* end,
269 : Address current_pc) {
270 : CHECK(!code.is_null());
271 : v8::internal::EmbeddedVector<char, 128> decode_buffer;
272 : v8::internal::EmbeddedVector<char, kOutBufferSize> out_buffer;
273 : StringBuilder out(out_buffer.start(), out_buffer.length());
274 : byte* pc = begin;
275 : disasm::Disassembler d(converter,
276 : disasm::Disassembler::kContinueOnUnimplementedOpcode);
277 : RelocIterator* it = nullptr;
278 : CodeCommentsIterator cit(code.code_comments());
279 : // Relocation exists if we either have no isolate (wasm code),
280 : // or we have an isolate and it is not an off-heap instruction stream.
281 : if (!isolate ||
282 : !InstructionStream::PcIsOffHeap(isolate, bit_cast<Address>(begin))) {
283 : it = new RelocIterator(code);
284 : } else {
285 : // No relocation information when printing code stubs.
286 : }
287 : int constants = -1; // no constants being decoded at the start
288 :
289 : while (pc < end) {
290 : // First decode instruction so that we know its length.
291 : byte* prev_pc = pc;
292 : if (constants > 0) {
293 : SNPrintF(decode_buffer,
294 : "%08x constant",
295 : *reinterpret_cast<int32_t*>(pc));
296 : constants--;
297 : pc += 4;
298 : } else {
299 : int num_const = d.ConstantPoolSizeAt(pc);
300 : if (num_const >= 0) {
301 : SNPrintF(decode_buffer,
302 : "%08x constant pool begin (num_const = %d)",
303 : *reinterpret_cast<int32_t*>(pc), num_const);
304 : constants = num_const;
305 : pc += 4;
306 : } else if (it != nullptr && !it->done() &&
307 : it->rinfo()->pc() == reinterpret_cast<Address>(pc) &&
308 : it->rinfo()->rmode() == RelocInfo::INTERNAL_REFERENCE) {
309 : // raw pointer embedded in code stream, e.g., jump table
310 : byte* ptr = *reinterpret_cast<byte**>(pc);
311 : SNPrintF(
312 : decode_buffer, "%08" V8PRIxPTR " jump table entry %4" PRIuS,
313 : reinterpret_cast<intptr_t>(ptr), static_cast<size_t>(ptr - begin));
314 : pc += sizeof(ptr);
315 : } else {
316 : decode_buffer[0] = '\0';
317 : pc += d.InstructionDecode(decode_buffer, pc);
318 : }
319 : }
320 :
321 : // Collect RelocInfo for this instruction (prev_pc .. pc-1)
322 : std::vector<const char*> comments;
323 : std::vector<Address> pcs;
324 : std::vector<RelocInfo::Mode> rmodes;
325 : std::vector<intptr_t> datas;
326 : if (it != nullptr) {
327 : while (!it->done() && it->rinfo()->pc() < reinterpret_cast<Address>(pc)) {
328 : // Collect all data.
329 : pcs.push_back(it->rinfo()->pc());
330 : rmodes.push_back(it->rinfo()->rmode());
331 : datas.push_back(it->rinfo()->data());
332 : it->next();
333 : }
334 : }
335 : while (cit.HasCurrent() &&
336 : cit.GetPCOffset() < static_cast<Address>(pc - begin)) {
337 : comments.push_back(cit.GetComment());
338 : cit.Next();
339 : }
340 :
341 : // Comments.
342 : for (size_t i = 0; i < comments.size(); i++) {
343 : out.AddFormatted(" %s", comments[i]);
344 : DumpBuffer(os, &out);
345 : }
346 :
347 : // Instruction address and instruction offset.
348 : if (FLAG_log_colour && reinterpret_cast<Address>(prev_pc) == current_pc) {
349 : // If this is the given "current" pc, make it yellow and bold.
350 : out.AddFormatted("\033[33;1m");
351 : }
352 : out.AddFormatted("%p %4" V8PRIxPTRDIFF " ", static_cast<void*>(prev_pc),
353 : prev_pc - begin);
354 :
355 : // Instruction.
356 : out.AddFormatted("%s", decode_buffer.start());
357 :
358 : // Print all the reloc info for this instruction which are not comments.
359 : for (size_t i = 0; i < pcs.size(); i++) {
360 : // Put together the reloc info
361 : const CodeReference& host = code;
362 : Address constant_pool =
363 : host.is_null() ? kNullAddress : host.constant_pool();
364 : RelocInfo relocinfo(pcs[i], rmodes[i], datas[i], Code(), constant_pool);
365 :
366 : bool first_reloc_info = (i == 0);
367 : PrintRelocInfo(&out, isolate, ref_encoder, os, code, &relocinfo,
368 : first_reloc_info);
369 : }
370 :
371 : // If this is a constant pool load and we haven't found any RelocInfo
372 : // already, check if we can find some RelocInfo for the target address in
373 : // the constant pool.
374 : if (pcs.empty() && !code.is_null()) {
375 : RelocInfo dummy_rinfo(reinterpret_cast<Address>(prev_pc),
376 : RelocInfo::NONE,
377 : 0, Code());
378 : if (dummy_rinfo.IsInConstantPool()) {
379 : Address constant_pool_entry_address =
380 : dummy_rinfo.constant_pool_entry_address();
381 : RelocIterator reloc_it(code);
382 : while (!reloc_it.done()) {
383 : if (reloc_it.rinfo()->IsInConstantPool() &&
384 : (reloc_it.rinfo()->constant_pool_entry_address() ==
385 : constant_pool_entry_address)) {
386 : PrintRelocInfo(&out, isolate, ref_encoder, os, code,
387 : reloc_it.rinfo());
388 : break;
389 : }
390 : reloc_it.next();
391 : }
392 : }
393 : }
394 :
395 : if (FLAG_log_colour && reinterpret_cast<Address>(prev_pc) == current_pc) {
396 : out.AddFormatted("\033[m");
397 : }
398 :
399 : DumpBuffer(os, &out);
400 : }
401 :
402 : // Emit comments following the last instruction (if any).
403 : while (cit.HasCurrent() &&
404 : cit.GetPCOffset() < static_cast<Address>(pc - begin)) {
405 : out.AddFormatted(" %s", cit.GetComment());
406 : DumpBuffer(os, &out);
407 : cit.Next();
408 : }
409 :
410 : delete it;
411 : return static_cast<int>(pc - begin);
412 : }
413 :
414 : int Disassembler::Decode(Isolate* isolate, std::ostream* os, byte* begin,
415 : byte* end, CodeReference code, Address current_pc) {
416 : V8NameConverter v8NameConverter(isolate, code);
417 : if (isolate) {
418 : // We have an isolate, so support external reference names.
419 : SealHandleScope shs(isolate);
420 : DisallowHeapAllocation no_alloc;
421 : ExternalReferenceEncoder ref_encoder(isolate);
422 : return DecodeIt(isolate, &ref_encoder, os, code, v8NameConverter, begin,
423 : end, current_pc);
424 : } else {
425 : // No isolate => isolate-independent code. No external reference names.
426 : return DecodeIt(nullptr, nullptr, os, code, v8NameConverter, begin, end,
427 : current_pc);
428 : }
429 : }
430 :
431 : #else // ENABLE_DISASSEMBLER
432 :
433 0 : int Disassembler::Decode(Isolate* isolate, std::ostream* os, byte* begin,
434 : byte* end, CodeReference code, Address current_pc) {
435 0 : return 0;
436 : }
437 :
438 : #endif // ENABLE_DISASSEMBLER
439 :
440 : } // namespace internal
441 120216 : } // namespace v8
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