Replacing assembly-implemented glibc functions to C-implemented, how to

Ángel González
Sun Jul 1 17:13:00 GMT 2012

On 01/07/12 14:51, Journeyer J. Joh wrote:
> Hello list,
> I am now checking all assembly-implemented parts from glibc.
> I need to replace all of them with C funcions so that I can prepare an
> architecture independent glibc.
> In the header file cdefs.h ,in misc/sys of glibc, I found the macro __REDIRECT.
> It seems that __REDIRECT redirects C function name to the Assembly
> function name.
> And there is a comment about this.
> 175 /* __asm__ ("xyz") is used throughout the headers to rename functions
> 176    at the assembly language level.  This is wrapped by the __REDIRECT
> 177    macro, in order to support compilers that can do this some other
> 178    way.  When compilers don't support asm-names at all, we have to do
> 179    preprocessor tricks instead (which don't have exactly the right
> 180    semantics, but it's the best we can do).
> 181
> 182    Example:
> 183    int __REDIRECT(setpgrp, (__pid_t pid, __pid_t pgrp), setpgid); */
> But I cannot understand the exact meaning of the comment above.
> Could someone explain me how I can get rid of all assembly-implemented
> functions from glibc?
void function() __asm__ ("xyz")

Specifies an assembler name of xyz for function. It isn't providing
assembler code.
So you can keep it. It doesn't add binary dependencies.

> Should I enable the part below and add some plugin to the compiler?

Note you'll need to keep syscall() in assembler. System calls are
architecture specific.

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