Why keep embedded.S in v8_snapshot?

[Yahan Lu]

V8 disable Embedded Builtins ( https://v8.dev/blog/short-builtin-calls) and load builtins from snapshot_blob.bin. I think v8 don't need to add embedded.S into source.

if (emit_builtins_as_inline_asm) {

deps += [ ":asm_to_inline_asm_default" ]

sources += [ "$target_gen_dir/embedded.cc" ]

} else {

sources += [ "$target_gen_dir/embedded.S" ]

}

[Yahan Lu]

I see only these builtins from embedded.S

extern "C" {

void Builtins_InterpreterEnterAtBytecode();

void Builtins_InterpreterEnterAtNextBytecode();

void Builtins_ContinueToCodeStubBuiltinWithResult();

void Builtins_ContinueToCodeStubBuiltin();

void Builtins_ContinueToJavaScriptBuiltinWithResult();

void Builtins_ContinueToJavaScriptBuiltin();

void construct_stub_create_deopt_addr();

void construct_stub_invoke_deopt_addr();

void Builtins_BaselineOrInterpreterEnterAtBytecode();

void Builtins_BaselineOrInterpreterEnterAtNextBytecode();

void Builtins_RestartFrameTrampoline();

typedef void (*function_ptr)();

}

[Wenqin Yang]

IIUC, the current builtins is embedded into d8 binary, at least x64 did.

Let's take `Builtins_LoadGlobalIC` as an example:

here are the contents for it in the `embedded.S`:

here are contents from `objdump -d -C d8`:

We could see they're same code, and there is `Builtins_LoadGlobalIC` symbol in d8 binary, so we could say the builtins were embedded?

I suppose the second image you posted may just contains a part of builtins not all builtins, it may just use to verify the address of these builtins, is it correct?