Re: [PATCH 1/2] gdb: remove some GCC version checks

[Pedro Alves <pedro@palves.net>]

On 2024-02-21 02:19, Simon Marchi wrote:

> 
> diff --git a/gdb/nat/x86-gcc-cpuid.h b/gdb/nat/x86-gcc-cpuid.h
> index dfd12587d813..b2eda44a2294 100644
> --- a/gdb/nat/x86-gcc-cpuid.h
> +++ b/gdb/nat/x86-gcc-cpuid.h
> @@ -195,7 +195,6 @@ __get_cpuid_max (unsigned int __ext, unsigned int *__sig)
>  
>  #ifndef __x86_64__
>    /* See if we can use cpuid.  On AMD64 we always can.  */
> -#if __GNUC__ >= 3
>    __asm__ ("pushf{l|d}\n\t"
>  	   "pushf{l|d}\n\t"
>  	   "pop{l}\t%0\n\t"
> @@ -208,22 +207,6 @@ __get_cpuid_max (unsigned int __ext, unsigned int *__sig)
>  	   "popf{l|d}\n\t"
>  	   : "=&r" (__eax), "=&r" (__ebx)
>  	   : "i" (0x00200000));
> -#else
> -/* Host GCCs older than 3.0 weren't supporting Intel asm syntax
> -   nor alternatives in i386 code.  */
> -  __asm__ ("pushfl\n\t"
> -	   "pushfl\n\t"
> -	   "popl\t%0\n\t"
> -	   "movl\t%0, %1\n\t"
> -	   "xorl\t%2, %0\n\t"
> -	   "pushl\t%0\n\t"
> -	   "popfl\n\t"
> -	   "pushfl\n\t"
> -	   "popl\t%0\n\t"
> -	   "popfl\n\t"
> -	   : "=&r" (__eax), "=&r" (__ebx)
> -	   : "i" (0x00200000));
> -#endif
>  
>    if (!((__eax ^ __ebx) & 0x00200000))
>      return 0;

It would be better IMO to avoid local changes to this file, especially if they're not
really needed:

/*
 * Helper cpuid.h file copied from gcc-6.0.0.  Code in gdb should not
                       ^^^^^^^^^^^^^^^^^^^^^
 * include this directly, but pull in x86-cpuid.h and use that func.
 */

At some point, someone may want to pull a newer version from GCC, and local changes
just make that a little more difficult.

> diff --git a/gdbserver/tracepoint.h b/gdbserver/tracepoint.h
> index 8b232324d2ec..6369e91aa276 100644
> --- a/gdbserver/tracepoint.h
> +++ b/gdbserver/tracepoint.h
> @@ -38,11 +38,7 @@ void initialize_tracepoint (void);
>  #if defined _WIN32 || defined __CYGWIN__
>  # define EXPORTED_SYMBOL __declspec (dllexport)
>  #else
> -# if __GNUC__ >= 4
>  #  define EXPORTED_SYMBOL __attribute__ ((visibility ("default")))

That "#  define" line should be "reindented".

> -# else
> -#  define EXPORTED_SYMBOL
> -# endif
>  #endif