minix/common/include/minix/compiler.h
Gianluca Guida fa59fc6eb4 Move shared headers in common/include
Headers that will be shared between old includes and NetBSD-like includes
are moved into common/include tree. They are still copied in /usr/include
in 'make includes', so compilation and programs aren't be affected.
2011-02-06 22:59:02 +00:00

49 lines
2 KiB
C

/* Definitions for compiler-specific features. */
#ifndef _MINIX_COMPILER_H
#define _MINIX_COMPILER_H
/*===========================================================================*
* Compiler overrides *
*===========================================================================*/
/* ACK */
#ifdef __ACK__
#include <minix/compiler-ack.h>
#endif
/*===========================================================================*
* Default values *
*===========================================================================*/
/*
* cdecl calling convention expects the callee to pop the hidden pointer on
* struct return. For example, GCC and LLVM comply with this (tested on IA32).
*/
#ifndef BYTES_TO_POP_ON_STRUCT_RETURN
#define BYTES_TO_POP_ON_STRUCT_RETURN $4
#endif
/*
* cdecl calling convention requires to push arguments on the stack in a
* reverse order to easily support variadic arguments. Thus, instead of
* using the proper stdarg.h macros (that nowadays are
* compiler-dependant), it may be tempting to directly take the address of
* the last argument and considering it as the start of an array. This is
* a shortcut that avoid looping to get all the arguments as the CPU
* already pushed them on the stack before the call to the function.
*
* Unfortunately, such an assumption is strictly compiler-dependant and
* compilers are free to move the last argument on the stack, as a local
* variable, and return the address of the location where the argument was
* stored, if asked for. This will break things as the rest of the array's
* argument are stored elsewhere (typically, a couple of words above the
* location where the argument was stored).
*
* Conclusion: if unsure on what the compiler may do, do not make any
* assumption and use the right (typically compiler-dependant) macros.
*/
#ifndef FUNC_ARGS_ARRAY
#define FUNC_ARGS_ARRAY 0
#endif
#endif /* _MINIX_COMPILER_H */