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Unified Diff: src/wasm/wasm-function-name-table.cc

Issue 1970503004: [wasm] Differentiate unnamed and empty names (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@add-utf8-check
Patch Set: Created 4 years, 7 months ago
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Index: src/wasm/wasm-function-name-table.cc
diff --git a/src/wasm/wasm-function-name-table.cc b/src/wasm/wasm-function-name-table.cc
index 2ba06748bedcaca09e37959e8dae4821690dba7f..14acc856c42d5b30869dd83232917890a144ac96 100644
--- a/src/wasm/wasm-function-name-table.cc
+++ b/src/wasm/wasm-function-name-table.cc
@@ -15,10 +15,12 @@ namespace wasm {
// module, then the first (kIntSize * (N+1)) bytes are integer entries.
// The first integer entry encodes the number of functions in the module.
// The entries 1 to N contain offsets into the second part of this array.
+// If a function is unnamed (not to be confused with an empty name), then the
+// integer entry is the negative offset of the next function name.
titzer 2016/05/12 09:05:51 Why does it have to be the negative offset of the
Clemens Hammacher 2016/05/12 09:45:57 The negative offset of the next function name allo
titzer 2016/05/12 09:54:36 ok
// After these N+1 integer entries, the second part begins, which holds a
// concatenation of all function names.
//
-// Returns undefined if the array length would not fit in an integer value
+// Returns undefined if the array length would not fit in an integer value.
Handle<Object> BuildFunctionNamesTable(Isolate* isolate, WasmModule* module) {
uint64_t func_names_length = 0;
for (auto& func : module->functions) func_names_length += func.name_length;
@@ -37,35 +39,46 @@ Handle<Object> BuildFunctionNamesTable(Isolate* isolate, WasmModule* module) {
int func_index = 0;
for (WasmFunction& fun : module->functions) {
WasmName name = module->GetNameOrNull(&fun);
- func_names_array->copy_in(current_offset,
- reinterpret_cast<const byte*>(name.start()),
- name.length());
- func_names_array->set_int(func_index + 1, current_offset);
- current_offset += name.length();
+ if (name.start() == nullptr) {
+ func_names_array->set_int(func_index + 1, -current_offset);
+ } else {
+ func_names_array->copy_in(current_offset,
+ reinterpret_cast<const byte*>(name.start()),
+ name.length());
+ func_names_array->set_int(func_index + 1, current_offset);
+ current_offset += name.length();
+ }
++func_index;
}
return func_names_array;
}
+// Extract the function name for the given function index from the function name
+// table.
+//
+// Returns undefined if the function index is invalid or the respective function
+// name is no valid UTF-8 string; returns null for unnamed functions (not to be
titzer 2016/05/12 09:05:51 s/no valid/not a valid/ Why not just return undef
Clemens Hammacher 2016/05/12 09:45:57 I am not the JavaScript expert, but I think undefi
titzer 2016/05/12 09:54:36 I think it's OK to use undefined for both here: th
+// confused with empty names).
Handle<Object> GetWasmFunctionNameFromTable(Handle<ByteArray> func_names_array,
uint32_t func_index) {
uint32_t num_funcs = static_cast<uint32_t>(func_names_array->get_int(0));
DCHECK(static_cast<int>(num_funcs) >= 0);
- auto undefined = [&func_names_array]() -> Handle<Object> {
- return func_names_array->GetIsolate()->factory()->undefined_value();
- };
- if (func_index >= num_funcs) return undefined();
+ Factory* factory = func_names_array->GetIsolate()->factory();
+ if (func_index >= num_funcs) return factory->undefined_value();
int offset = func_names_array->get_int(func_index + 1);
+ if (offset < 0) return factory->null_value();
int next_offset = func_index == num_funcs - 1
? func_names_array->length()
- : func_names_array->get_int(func_index + 2);
+ : abs(func_names_array->get_int(func_index + 2));
ScopedVector<byte> buffer(next_offset - offset);
func_names_array->copy_out(offset, buffer.start(), next_offset - offset);
- if (!IsValidUtf8(buffer.start(), buffer.length())) return undefined();
- MaybeHandle<Object> maybe_name =
- func_names_array->GetIsolate()->factory()->NewStringFromUtf8(
- Vector<const char>::cast(buffer));
- return maybe_name.is_null() ? undefined() : maybe_name.ToHandleChecked();
+ if (!IsValidUtf8(buffer.start(), buffer.length()))
+ return factory->undefined_value();
+ Handle<Object> maybe_name;
+ if (!factory->NewStringFromUtf8(Vector<const char>::cast(buffer))
+ .ToHandle(&maybe_name))
+ maybe_name = factory->undefined_value();
+ return maybe_name;
}
} // namespace wasm

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