1 // Copyright 2016 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/assert-scope.h"
6 #include "src/debug/debug.h"
7 #include "src/factory.h"
8 #include "src/isolate.h"
9 #include "src/wasm/module-decoder.h"
10 #include "src/wasm/wasm-module.h"
11 #include "src/wasm/wasm-objects.h"
12
13 using namespace v8::internal;
14 using namespace v8::internal::wasm;
15
16 namespace {
17
18 enum {
19 kWasmDebugInfoWasmObj,
20 kWasmDebugInfoWasmBytesHash,
21 kWasmDebugInfoAsmJsOffsets,
22 kWasmDebugInfoNumEntries
23 };
24
25 // TODO(clemensh): Move asm.js offset tables to the compiled module.
GetAsmJsOffsetTables(Handle<WasmDebugInfo> debug_info,Isolate * isolate)26 FixedArray *GetAsmJsOffsetTables(Handle<WasmDebugInfo> debug_info,
27 Isolate *isolate) {
28 Object *offset_tables = debug_info->get(kWasmDebugInfoAsmJsOffsets);
29 if (!offset_tables->IsUndefined(isolate)) {
30 return FixedArray::cast(offset_tables);
31 }
32
33 Handle<JSObject> wasm_instance(debug_info->wasm_instance(), isolate);
34 Handle<WasmCompiledModule> compiled_module(GetCompiledModule(*wasm_instance),
35 isolate);
36 DCHECK(compiled_module->has_asm_js_offset_tables());
37
38 AsmJsOffsetsResult asm_offsets;
39 {
40 Handle<ByteArray> asm_offset_tables =
41 compiled_module->asm_js_offset_tables();
42 DisallowHeapAllocation no_gc;
43 const byte *bytes_start = asm_offset_tables->GetDataStartAddress();
44 const byte *bytes_end = bytes_start + asm_offset_tables->length();
45 asm_offsets = wasm::DecodeAsmJsOffsets(bytes_start, bytes_end);
46 }
47 // Wasm bytes must be valid and must contain asm.js offset table.
48 DCHECK(asm_offsets.ok());
49 DCHECK_GE(static_cast<size_t>(kMaxInt), asm_offsets.val.size());
50 int num_functions = static_cast<int>(asm_offsets.val.size());
51 DCHECK_EQ(
52 wasm::GetNumberOfFunctions(handle(debug_info->wasm_instance())),
53 static_cast<int>(num_functions +
54 compiled_module->module()->num_imported_functions));
55 Handle<FixedArray> all_tables =
56 isolate->factory()->NewFixedArray(num_functions);
57 debug_info->set(kWasmDebugInfoAsmJsOffsets, *all_tables);
58 for (int func = 0; func < num_functions; ++func) {
59 std::vector<std::pair<int, int>> &func_asm_offsets = asm_offsets.val[func];
60 if (func_asm_offsets.empty()) continue;
61 size_t array_size = 2 * kIntSize * func_asm_offsets.size();
62 CHECK_LE(array_size, static_cast<size_t>(kMaxInt));
63 ByteArray *arr =
64 *isolate->factory()->NewByteArray(static_cast<int>(array_size));
65 all_tables->set(func, arr);
66 int idx = 0;
67 for (std::pair<int, int> p : func_asm_offsets) {
68 // Byte offsets must be strictly monotonously increasing:
69 DCHECK(idx == 0 || p.first > arr->get_int(idx - 2));
70 arr->set_int(idx++, p.first);
71 arr->set_int(idx++, p.second);
72 }
73 DCHECK_EQ(arr->length(), idx * kIntSize);
74 }
75 return *all_tables;
76 }
77 } // namespace
78
New(Handle<JSObject> wasm)79 Handle<WasmDebugInfo> WasmDebugInfo::New(Handle<JSObject> wasm) {
80 Isolate *isolate = wasm->GetIsolate();
81 Factory *factory = isolate->factory();
82 Handle<FixedArray> arr =
83 factory->NewFixedArray(kWasmDebugInfoNumEntries, TENURED);
84 arr->set(kWasmDebugInfoWasmObj, *wasm);
85 int hash = 0;
86 Handle<SeqOneByteString> wasm_bytes = GetWasmBytes(wasm);
87 {
88 DisallowHeapAllocation no_gc;
89 hash = StringHasher::HashSequentialString(
90 wasm_bytes->GetChars(), wasm_bytes->length(), kZeroHashSeed);
91 }
92 Handle<Object> hash_obj = factory->NewNumberFromInt(hash, TENURED);
93 arr->set(kWasmDebugInfoWasmBytesHash, *hash_obj);
94
95 return Handle<WasmDebugInfo>::cast(arr);
96 }
97
IsDebugInfo(Object * object)98 bool WasmDebugInfo::IsDebugInfo(Object *object) {
99 if (!object->IsFixedArray()) return false;
100 FixedArray *arr = FixedArray::cast(object);
101 return arr->length() == kWasmDebugInfoNumEntries &&
102 IsWasmInstance(arr->get(kWasmDebugInfoWasmObj)) &&
103 arr->get(kWasmDebugInfoWasmBytesHash)->IsNumber();
104 }
105
cast(Object * object)106 WasmDebugInfo *WasmDebugInfo::cast(Object *object) {
107 DCHECK(IsDebugInfo(object));
108 return reinterpret_cast<WasmDebugInfo *>(object);
109 }
110
wasm_instance()111 JSObject *WasmDebugInfo::wasm_instance() {
112 return JSObject::cast(get(kWasmDebugInfoWasmObj));
113 }
114
GetAsmJsSourcePosition(Handle<WasmDebugInfo> debug_info,int func_index,int byte_offset)115 int WasmDebugInfo::GetAsmJsSourcePosition(Handle<WasmDebugInfo> debug_info,
116 int func_index, int byte_offset) {
117 Isolate *isolate = debug_info->GetIsolate();
118 Handle<JSObject> instance(debug_info->wasm_instance(), isolate);
119 FixedArray *offset_tables = GetAsmJsOffsetTables(debug_info, isolate);
120
121 WasmCompiledModule *compiled_module = wasm::GetCompiledModule(*instance);
122 int num_imported_functions =
123 compiled_module->module()->num_imported_functions;
124 DCHECK_LE(num_imported_functions, func_index);
125 func_index -= num_imported_functions;
126 DCHECK_LT(func_index, offset_tables->length());
127 ByteArray *offset_table = ByteArray::cast(offset_tables->get(func_index));
128
129 // Binary search for the current byte offset.
130 int left = 0; // inclusive
131 int right = offset_table->length() / kIntSize / 2; // exclusive
132 DCHECK_LT(left, right);
133 while (right - left > 1) {
134 int mid = left + (right - left) / 2;
135 if (offset_table->get_int(2 * mid) <= byte_offset) {
136 left = mid;
137 } else {
138 right = mid;
139 }
140 }
141 // There should be an entry for each position that could show up on the stack
142 // trace:
143 DCHECK_EQ(byte_offset, offset_table->get_int(2 * left));
144 return offset_table->get_int(2 * left + 1);
145 }
146