Ben Murdoch | c561043 | 2016-08-08 18:44:38 +0100 | [diff] [blame^] | 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 | if (!unibrow::Utf8::Validate(buffer.start(), buffer.length())) { |
| 64 | return undefined(); |
| 65 | } |
| 66 | MaybeHandle<Object> maybe_name = |
| 67 | func_names_array->GetIsolate()->factory()->NewStringFromUtf8( |
| 68 | Vector<const char>::cast(buffer)); |
| 69 | return maybe_name.is_null() ? undefined() : maybe_name.ToHandleChecked(); |
| 70 | } |
| 71 | |
| 72 | } // namespace wasm |
| 73 | } // namespace internal |
| 74 | } // namespace v8 |