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LibWasm: Fix lossy NaN bit pattern conversions in spec-test gen

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This commit is contained in:
Diego 2024-07-06 08:01:26 -07:00 committed by Ali Mohammad Pur
parent c882498d44
commit c103001f16
Notes: sideshowbarker 2024-07-17 08:13:43 +09:00 
Author: https://github.com/dzfrias
Commit: https://github.com/LadybirdBrowser/ladybird/commit/c103001f16
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/459
Reviewed-by: https://github.com/alimpfard
2 changed files with 23 additions and 9 deletions
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12
Meta/generate-libwasm-spec-test.py
View File

@ -221,9 +221,11 @@ def gen_value(value: WasmValue, as_arg=False) -> str:
f = struct.unpack("d", b)[0]
return f
def float_to_str(f: float, preserve_nan_sign=False) -> str:
def float_to_str(bits: int, *, double=False, preserve_nan_sign=False) -> str:
f = int_to_float64_bitcast(bits) if double else int_to_float_bitcast(bits)
if math.isnan(f) and preserve_nan_sign:
f_bytes = struct.pack("d", f)
f_bytes = bits.to_bytes(8 if double else 4, byteorder="little")
# -NaN does not preserve the sign bit in JavaScript land, so if
# we want to preserve NaN "sign", we pass in raw bytes
return f"new Uint8Array({list(f_bytes)})"
@ -251,9 +253,11 @@ def gen_value(value: WasmValue, as_arg=False) -> str:
case "i64":
return str(unsigned_to_signed(int(value.value), 64)) + "n"
case "f32":
return float_to_str(int_to_float_bitcast(int(value.value)), as_arg)
return float_to_str(
int(value.value), double=False, preserve_nan_sign=as_arg
)
case "f64":
return float_to_str(int_to_float64_bitcast(int(value.value)), as_arg)
return float_to_str(int(value.value), double=True, preserve_nan_sign=as_arg)
case "externref" | "funcref" | "v128":
return value.value
case _:

20
Tests/LibWasm/test-wasm.cpp
View File

@ -259,13 +259,13 @@ JS_DEFINE_NATIVE_FUNCTION(WebAssemblyModule::wasm_invoke)
if (argument.is_object()) {
auto object = MUST(argument.to_object(vm));
// Uint8Array allows for raw bytes to be passed into Wasm. This is
// particularly useful for preserving the sign bit of a NaN
// particularly useful for NaN bit patterns
if (!is<JS::Uint8Array>(*object))
return vm.throw_completion<JS::TypeError>("Expected a Uint8Array object"sv);
auto& array = static_cast<JS::Uint8Array&>(*object);
if (array.array_length().length() != 8)
return vm.throw_completion<JS::TypeError>("Expected a Uint8Array of size 8"sv);
memcpy(&double_value, array.data().data(), sizeof(double));
if (array.array_length().length() > 8)
return vm.throw_completion<JS::TypeError>("Expected a Uint8Array of size <= 8"sv);
memcpy(&double_value, array.data().data(), array.array_length().length());
} else if (!argument.is_bigint())
double_value = TRY(argument.to_double(vm));
switch (param.kind()) {
@ -281,7 +281,17 @@ JS_DEFINE_NATIVE_FUNCTION(WebAssemblyModule::wasm_invoke)
}
break;
case Wasm::ValueType::Kind::F32:
arguments.append(Wasm::Value(static_cast<float>(double_value)));
// double_value should contain up to 8 bytes of information,
// if we were passed a Uint8Array. If the expected arg is a
// float, we were probably passed a Uint8Array of size 4. So
// we copy those bytes into a float value.
if (argument.is_object()) {
float float_value = 0;
memcpy(&float_value, &double_value, sizeof(float));
arguments.append(Wasm::Value(float_value));
} else {
arguments.append(Wasm::Value(static_cast<float>(double_value)));
}
break;
case Wasm::ValueType::Kind::F64:
arguments.append(Wasm::Value(static_cast<double>(double_value)));