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| 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/wasm/wasm-function-name-table.h" |
| 6 |
| 7 #include "src/wasm/wasm-module.h" |
| 8 |
| 9 namespace v8 { |
| 10 namespace internal { |
| 11 namespace wasm { |
| 12 |
| 13 // Build an array with all function names. If there are N functions in the |
| 14 // module, then the first (kIntSize * (N+1)) bytes are integer entries. |
| 15 // The first integer entry encodes the number of functions in the module. |
| 16 // The entries 1 to N contain offsets into the second part of this array. |
| 17 // After these N+1 integer entries, the second part begins, which holds a |
| 18 // concatenation of all function names. |
| 19 // |
| 20 // Returns undefined if the array length would not fit in an integer value |
| 21 Handle<Object> BuildFunctionNamesTable(Isolate* isolate, WasmModule* module) { |
| 22 uint64_t func_names_length = 0; |
| 23 for (auto& func : module->functions) func_names_length += func.name_length; |
| 24 int num_funcs_int = static_cast<int>(module->functions.size()); |
| 25 int current_offset = (num_funcs_int + 1) * kIntSize; |
| 26 uint64_t total_array_length = current_offset + func_names_length; |
| 27 int total_array_length_int = static_cast<int>(total_array_length); |
| 28 // Check for overflow. Just skip function names if it happens. |
| 29 if (total_array_length_int != total_array_length || num_funcs_int < 0 || |
| 30 num_funcs_int != module->functions.size()) |
| 31 return isolate->factory()->undefined_value(); |
| 32 Handle<ByteArray> func_names_array = |
| 33 isolate->factory()->NewByteArray(total_array_length_int, TENURED); |
| 34 if (func_names_array.is_null()) return isolate->factory()->undefined_value(); |
| 35 func_names_array->set_int(0, num_funcs_int); |
| 36 int func_index = 0; |
| 37 for (WasmFunction& fun : module->functions) { |
| 38 WasmName name = module->GetNameOrNull(&fun); |
| 39 func_names_array->copy_in(current_offset, |
| 40 reinterpret_cast<const byte*>(name.start()), |
| 41 name.length()); |
| 42 func_names_array->set_int(func_index + 1, current_offset); |
| 43 current_offset += name.length(); |
| 44 ++func_index; |
| 45 } |
| 46 return func_names_array; |
| 47 } |
| 48 |
| 49 Handle<Object> GetWasmFunctionNameFromTable(Handle<ByteArray> func_names_array, |
| 50 uint32_t func_index) { |
| 51 uint32_t num_funcs = static_cast<uint32_t>(func_names_array->get_int(0)); |
| 52 DCHECK(static_cast<int>(num_funcs) >= 0); |
| 53 auto undefined = [&func_names_array]() -> Handle<Object> { |
| 54 return func_names_array->GetIsolate()->factory()->undefined_value(); |
| 55 }; |
| 56 if (func_index >= num_funcs) return undefined(); |
| 57 int offset = func_names_array->get_int(func_index + 1); |
| 58 int next_offset = func_index == num_funcs - 1 |
| 59 ? func_names_array->length() |
| 60 : func_names_array->get_int(func_index + 2); |
| 61 ScopedVector<byte> buffer(next_offset - offset); |
| 62 func_names_array->copy_out(offset, buffer.start(), next_offset - offset); |
| 63 MaybeHandle<Object> maybe_name = |
| 64 func_names_array->GetIsolate()->factory()->NewStringFromUtf8( |
| 65 Vector<const char>::cast(buffer)); |
| 66 return maybe_name.is_null() ? undefined() : maybe_name.ToHandleChecked(); |
| 67 } |
| 68 |
| 69 } // namespace wasm |
| 70 } // namespace internal |
| 71 } // namespace v8 |
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