Could __builtin_printf parameters be optimized when being compiled

Jonny Grant jg@jguk.org
Wed Feb 15 14:18:37 GMT 2023


Hi
Has GCC considered an improvement to "compile out" from the builtin printf the strings? That being to change it to just be something like puts("file /app/example.cpp:4")
I had a look, but couldn't find it being asked before.

This is just a short example to demonstrate.
It would be useful to see the exact string in the debugger "file /app/example.cpp:4", also it saves a few lines of asm.

https://godbolt.org/z/aKz3o6aPd


int main()
{
    __builtin_printf("file %s:%d", __FILE__, __LINE__);
}


.LC0:
        .string "/app/example.cpp"
.LC1:
        .string "file %s:%d"
main:
        subq    $8, %rsp
        movl    $4, %edx
        movl    $.LC0, %esi
        xorl    %eax, %eax
        movl    $.LC1, %edi
        call    printf
        xorl    %eax, %eax
        addq    $8, %rsp
        ret


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