#ifndef COMPILER_H
#define COMPILER_H
/*
* Doxygen can't cope with some of the more esoteric areas of C, so we
* make its life simpler.
*
*/
#ifdef DOXYGEN
#define __attribute__(x)
#endif
/** @file
*
* Global compiler definitions.
*
* This file is implicitly included by every @c .c file in Etherboot.
* It defines global macros such as DBG().
*
* We arrange for each object to export the symbol @c obj_OBJECT
* (where @c OBJECT is the object name, e.g. @c rtl8139) as a global
* symbol, so that the linker can drag in selected object files from
* the library using <tt> -u obj_OBJECT </tt>.
*
*/
/* Force visibility of all symbols to "hidden", i.e. inform gcc that
* all symbol references resolve strictly within our final binary.
* This avoids unnecessary PLT/GOT entries on x86_64.
*
* This is a stronger claim than specifying "-fvisibility=hidden",
* since it also affects symbols marked with "extern".
*/
#ifndef ASSEMBLY
#if __GNUC__ >= 4
#pragma GCC visibility push(hidden)
#endif
#endif /* ASSEMBLY */
#undef _S1
#undef _S2
#undef _C1
#undef _C2
/** Concatenate non-expanded arguments */
#define _C1( x, y ) x ## y
/** Concatenate expanded arguments */
#define _C2( x, y ) _C1 ( x, y )
/** Stringify non-expanded argument */
#define _S1( x ) #x
/** Stringify expanded argument */
#define _S2( x ) _S1 ( x )
/**
* @defgroup symmacros Macros to provide or require explicit symbols
* @{
*/
/** Provide a symbol within this object file */
#ifdef ASSEMBLY
#define PROVIDE_SYMBOL( _sym ) \
.globl _sym ; \
.comm _sym, 0
#else /* ASSEMBLY */
#define PROVIDE_SYMBOL( _sym ) \
char _sym[0]
#endif /* ASSEMBLY */
/** Require a symbol within this object file
*
* The symbol is referenced by a relocation in a discarded section, so
* if it is not available at link time the link will fail.
*/
#ifdef ASSEMBLY
#define REQUIRE_SYMBOL( _sym ) \
.section ".discard", "a", @progbits ; \
.extern _sym ; \
.long _sym ; \
.previous
#else /* ASSEMBLY */
#define REQUIRE_SYMBOL( _sym ) \
extern char _sym; \
static char * _C2 ( _C2 ( __require_, _sym ), _C2 ( _, __LINE__ ) ) \
__attribute__ (( section ( ".discard" ), used )) \
= &_sym
#endif
/** Request that a symbol be available at runtime
*
* The requested symbol is entered as undefined into the symbol table
* for this object, so the linker will pull in other object files as
* necessary to satisfy the reference. However, the undefined symbol
* is not referenced in any relocations, so the link can still succeed
* if no file contains it.
*
* A symbol passed to this macro may not be referenced anywhere
* else in the file. If you want to do that, see IMPORT_SYMBOL().
*/
#ifdef ASSEMBLY
#define REQUEST_SYMBOL( _sym ) \
.equ __need_ ## _sym, _sym
#else /* ASSEMBLY */
#define REQUEST_SYMBOL( _sym ) \
__asm__ ( ".equ\t__need_" #_sym ", " #_sym )
#endif /* ASSEMBLY */
/** Set up a symbol to be usable in another file by IMPORT_SYMBOL()
*
* The symbol must already be marked as global.
*/
#define EXPORT_SYMBOL( _sym ) PROVIDE_SYMBOL ( __export_ ## _sym )
/** Make a symbol usable to this file if available at link time
*
* If no file passed to the linker contains the symbol, it will have
* @c NULL value to future uses. Keep in mind that the symbol value is
* really the @e address of a variable or function; see the code
* snippet below.
*
* In C using IMPORT_SYMBOL, you must specify the declaration as the
* second argument, for instance
*
* @code
* IMPORT_SYMBOL ( my_func, int my_func ( int arg ) );
* IMPORT_SYMBOL ( my_var, int my_var );
*
* void use_imports ( void ) {
* if ( my_func && &my_var )
* my_var = my_func ( my_var );
* }
* @endcode
*
* GCC considers a weak declaration to override a strong one no matter
* which comes first, so it is safe to include a header file declaring
* the imported symbol normally, but providing the declaration to
* IMPORT_SYMBOL is still required.
*
* If no EXPORT_SYMBOL declaration exists for the imported symbol in
* another file, the behavior will be most likely be identical to that
* for an unavailable symbol.
*/
#ifdef ASSEMBLY
#define IMPORT_SYMBOL( _sym ) \
REQUEST_SYMBOL ( __export_ ## _sym ) ; \
.weak _sym
#else /* ASSEMBLY */
#define IMPORT_SYMBOL( _sym, _decl ) \
REQUEST_SYMBOL ( __export_ ## _sym ) ; \
extern _decl __attribute__ (( weak ))
#endif
/** @} */
/**
* @defgroup objmacros Macros to provide or require explicit objects
* @{
*/
#define PREFIX_OBJECT( _prefix ) _C2 ( _prefix, OBJECT )
#define OBJECT_SYMBOL PREFIX_OBJECT ( obj_ )
#define REQUEST_EXPANDED( _sym ) REQUEST_SYMBOL ( _sym )
#define CONFIG_SYMBOL PREFIX_OBJECT ( obj_config_ )
/** Always provide the symbol for the current object (defined by -DOBJECT) */
PROVIDE_SYMBOL ( OBJECT_SYMBOL );
/** Pull in an object-specific configuration file if available */
REQUEST_EXPANDED ( CONFIG_SYMBOL );
/** Explicitly require another object */
#define REQUIRE_OBJECT( _obj ) REQUIRE_SYMBOL ( obj_ ## _obj )
/** Pull in another object if it exists */
#define REQUEST_OBJECT( _obj ) REQUEST_SYMBOL ( obj_ ## _obj )
/** @} */
/** Select file identifier for errno.h (if used) */
#define ERRFILE PREFIX_OBJECT ( ERRFILE_ )
/**
* @defgroup weakmacros Macros to manage weak symbol definitions
*
* Weak symbols allow one to reference a function in another file
* without necessarily requiring that file to be linked in. In their
* native form, the function will be @c NULL if its file is not linked
* in; these macros provide an inline wrapper that returns an
* appropriate error indication or default value.
*
* @{
*/
#ifndef ASSEMBLY
/** Mangle @a name into its weakly-referenced implementation */
#define __weak_impl( name ) _w_ ## name
/**
* Declare a weak function with inline safety wrapper
*
* @v ret Return type of weak function
* @v name Name of function to expose
* @v proto Parenthesized list of arguments with types
* @v args Parenthesized list of argument names
* @v dfl Value to return if weak function is not available
*/
#define __weak_decl( ret, name, proto, args, dfl ) \
ret __weak_impl( name ) proto __attribute__ (( weak )); \
static inline ret name proto { \
if ( __weak_impl( name ) ) \
return __weak_impl( name ) args; \
return dfl; \
}
#endif
/** @} */
/** @defgroup dbg Debugging infrastructure
* @{
*/
#ifndef ASSEMBLY
/** @def DBG
*
* Print a debugging message.
*
* The debug level is set at build time by specifying the @c DEBUG=
* parameter on the @c make command line. For example, to enable
* debugging for the PCI bus functions (in pci.c) in a @c .dsk image
* for the @c rtl8139 card, you could use the command line
*
* @code
*
* make bin/rtl8139.dsk DEBUG=pci
*
* @endcode
*
* This will enable the debugging statements (DBG()) in pci.c. If
* debugging is not enabled, DBG() statements will be ignored.
*
* You can enable debugging in several objects simultaneously by
* separating them with commas, as in
*
* @code
*
* make bin/rtl8139.dsk DEBUG=pci,buffer,heap
*
* @endcode
*
* You can increase the debugging level for an object by specifying it
* with @c :N, where @c N is the level, as in
*
* @code
*
* make bin/rtl8139.dsk DEBUG=pci,buffer:2,heap
*
* @endcode
*
* which would enable debugging for the PCI, buffer-handling and
* heap-allocation code, with the buffer-handling code at level 2.
*
*/
/*
* If debug_OBJECT is set to a true value, the macro DBG(...) will
* expand to printf(...) when compiling OBJECT, and the symbol
* DEBUG_LEVEL will be inserted into the object file.
*
*/
#define DEBUG_SYMBOL PREFIX_OBJECT ( debug_ )
/** printf() for debugging
*
* This function exists so that the DBG() macros can expand to
* printf() calls without dragging the printf() prototype into scope.
*
* As far as the compiler is concerned, dbg_printf() and printf() are
* completely unrelated calls; it's only at the assembly stage that
* references to the dbg_printf symbol are collapsed into references
* to the printf symbol.
*/
extern int __attribute__ (( format ( printf, 1, 2 ) ))
dbg_printf ( const char *fmt, ... ) asm ( "printf" );
extern void dbg_autocolourise ( unsigned long id );
extern void dbg_decolourise ( void );
extern void dbg_hex_dump_da ( unsigned long dispaddr,
const void *data, unsigned long len );
#if DEBUG_SYMBOL
#define DBGLVL_MAX DEBUG_SYMBOL
#else
#define DBGLVL_MAX 0
#endif
/* Allow for selective disabling of enabled debug levels */
#if DBGLVL_MAX
int __debug_disable;
#define DBGLVL ( DBGLVL_MAX & ~__debug_disable )
#define DBG_DISABLE( level ) do { \
__debug_disable |= ( (level) & DBGLVL_MAX ); \
} while ( 0 )
#define DBG_ENABLE( level ) do { \
__debug_disable &= ~( (level) & DBGLVL_MAX ); \
} while ( 0 )
#else
#define DBGLVL 0
#define DBG_DISABLE( level ) do { } while ( 0 )
#define DBG_ENABLE( level ) do { } while ( 0 )
#endif
#define DBGLVL_LOG 1
#define DBG_LOG ( DBGLVL & DBGLVL_LOG )
#define DBGLVL_EXTRA 2
#define DBG_EXTRA ( DBGLVL & DBGLVL_EXTRA )
#define DBGLVL_PROFILE 4
#define DBG_PROFILE ( DBGLVL & DBGLVL_PROFILE )
#define DBGLVL_IO 8
#define DBG_IO ( DBGLVL & DBGLVL_IO )
/**
* Print debugging message if we are at a certain debug level
*
* @v level Debug level
* @v ... printf() argument list
*/
#define DBG_IF( level, ... ) do { \
if ( DBG_ ## level ) { \
dbg_printf ( __VA_ARGS__ ); \
} \
} while ( 0 )
/**
* Print a hex dump if we are at a certain debug level
*
* @v level Debug level
* @v dispaddr Display address
* @v data Data to print
* @v len Length of data
*/
#define DBG_HDA_IF( level, dispaddr, data, len ) do { \
if ( DBG_ ## level ) { \
union { \
unsigned long ul; \
typeof ( dispaddr ) raw; \
} da; \
da.raw = dispaddr; \
dbg_hex_dump_da ( da.ul, data, len ); \
} \
} while ( 0 )
/**
* Print a hex dump if we are at a certain debug level
*
* @v level Debug level
* @v data Data to print
* @v len Length of data
*/
#define DBG_HD_IF( level, data, len ) do { \
const void *_data = data; \
DBG_HDA_IF ( level, _data, _data, len ); \
} while ( 0 )
/**
* Select colour for debug messages if we are at a certain debug level
*
* @v level Debug level
* @v id Message stream ID
*/
#define DBG_AC_IF( level, id ) do { \
if ( DBG_ ## level ) { \
union { \
unsigned long ul; \
typeof ( id ) raw; \
} dbg_stream; \
dbg_stream.raw = id; \
dbg_autocolourise ( dbg_stream.ul ); \
} \
} while ( 0 )
/**
* Revert colour for debug messages if we are at a certain debug level
*
* @v level Debug level
*/
#define DBG_DC_IF( level ) do { \
if ( DBG_ ## level ) { \
dbg_decolourise(); \
} \
} while ( 0 )
/* Autocolourising versions of the DBGxxx_IF() macros */
#define DBGC_IF( level, id, ... ) do { \
DBG_AC_IF ( level, id ); \
DBG_IF ( level, __VA_ARGS__ ); \
DBG_DC_IF ( level ); \
} while ( 0 )
#define DBGC_HDA_IF( level, id, ... ) do { \
DBG_AC_IF ( level, id ); \
DBG_HDA_IF ( level, __VA_ARGS__ ); \
DBG_DC_IF ( level ); \
} while ( 0 )
#define DBGC_HD_IF( level, id, ... ) do { \
DBG_AC_IF ( level, id ); \
DBG_HD_IF ( level, __VA_ARGS__ ); \
DBG_DC_IF ( level ); \
} while ( 0 )
/* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( LOG, ... )*/
#define DBG( ... ) DBG_IF ( LOG, __VA_ARGS__ )
#define DBG_HDA( ... ) DBG_HDA_IF ( LOG, __VA_ARGS__ )
#define DBG_HD( ... ) DBG_HD_IF ( LOG, __VA_ARGS__ )
#define DBGC( ... ) DBGC_IF ( LOG, __VA_ARGS__ )
#define DBGC_HDA( ... ) DBGC_HDA_IF ( LOG, __VA_ARGS__ )
#define DBGC_HD( ... ) DBGC_HD_IF ( LOG, __VA_ARGS__ )
/* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( EXTRA, ... )*/
#define DBG2( ... ) DBG_IF ( EXTRA, __VA_ARGS__ )
#define DBG2_HDA( ... ) DBG_HDA_IF ( EXTRA, __VA_ARGS__ )
#define DBG2_HD( ... ) DBG_HD_IF ( EXTRA, __VA_ARGS__ )
#define DBGC2( ... ) DBGC_IF ( EXTRA, __VA_ARGS__ )
#define DBGC2_HDA( ... ) DBGC_HDA_IF ( EXTRA, __VA_ARGS__ )
#define DBGC2_HD( ... ) DBGC_HD_IF ( EXTRA, __VA_ARGS__ )
/* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( PROFILE, ... )*/
#define DBGP( ... ) DBG_IF ( PROFILE, __VA_ARGS__ )
#define DBGP_HDA( ... ) DBG_HDA_IF ( PROFILE, __VA_ARGS__ )
#define DBGP_HD( ... ) DBG_HD_IF ( PROFILE, __VA_ARGS__ )
#define DBGCP( ... ) DBGC_IF ( PROFILE, __VA_ARGS__ )
#define DBGCP_HDA( ... ) DBGC_HDA_IF ( PROFILE, __VA_ARGS__ )
#define DBGCP_HD( ... ) DBGC_HD_IF ( PROFILE, __VA_ARGS__ )
/* Versions of the DBGxxx_IF() macros that imply DBGxxx_IF( IO, ... )*/
#define DBGIO( ... ) DBG_IF ( IO, __VA_ARGS__ )
#define DBGIO_HDA( ... ) DBG_HDA_IF ( IO, __VA_ARGS__ )
#define DBGIO_HD( ... ) DBG_HD_IF ( IO, __VA_ARGS__ )
#define DBGCIO( ... ) DBGC_IF ( IO, __VA_ARGS__ )
#define DBGCIO_HDA( ... ) DBGC_HDA_IF ( IO, __VA_ARGS__ )
#define DBGCIO_HD( ... ) DBGC_HD_IF ( IO, __VA_ARGS__ )
#if DEBUG_SYMBOL == 0
#define NDEBUG
#endif
#endif /* ASSEMBLY */
/** @} */
/** @defgroup attrs Miscellaneous attributes
* @{
*/
#ifndef ASSEMBLY
/** Declare a data structure as packed. */
#define PACKED __attribute__ (( packed ))
/** Declare a variable or data structure as unused. */
#define __unused __attribute__ (( unused ))
/**
* Declare a function as pure - i.e. without side effects
*/
#define __pure __attribute__ (( pure ))
/**
* Declare a function as const - i.e. it does not access global memory
* (including dereferencing pointers passed to it) at all.
* Must also not call any non-const functions.
*/
#define __const __attribute__ (( const ))
/**
* Declare a function's pointer parameters as non-null - i.e. force
* compiler to check pointers at compile time and enable possible
* optimizations based on that fact
*/
#define __nonnull __attribute__ (( nonnull ))
/**
* Declare a pointer returned by a function as a unique memory address
* as returned by malloc-type functions.
*/
#define __malloc __attribute__ (( malloc ))
/**
* Declare a function as used.
*
* Necessary only if the function is called only from assembler code.
*/
#define __used __attribute__ (( used ))
/** Declare a data structure to be aligned with 16-byte alignment */
#define __aligned __attribute__ (( aligned ( 16 ) ))
/** Declare a function to be always inline */
#define __always_inline __attribute__ (( always_inline ))
/**
* Shared data.
*
* To save space in the binary when multiple-driver images are
* compiled, uninitialised data areas can be shared between drivers.
* This will typically be used to share statically-allocated receive
* and transmit buffers between drivers.
*
* Use as e.g.
*
* @code
*
* struct {
* char rx_buf[NUM_RX_BUF][RX_BUF_SIZE];
* char tx_buf[TX_BUF_SIZE];
* } my_static_data __shared;
*
* @endcode
*
*/
#define __shared __asm__ ( "_shared_bss" ) __aligned
#endif /* ASSEMBLY */
/** @} */
/**
* Optimisation barrier
*/
#ifndef ASSEMBLY
#define barrier() __asm__ __volatile__ ( "" : : : "memory" )
#endif /* ASSEMBLY */
/**
* @defgroup licences Licence declarations
*
* For reasons that are partly historical, various different files
* within the gPXE codebase have differing licences.
*
* @{
*/
/** Declare a file as being in the public domain
*
* This licence declaration is applicable when a file states itself to
* be in the public domain.
*/
#define FILE_LICENCE_PUBLIC_DOMAIN \
PROVIDE_SYMBOL ( __licence_public_domain )
/** Declare a file as being under version 2 (or later) of the GNU GPL
*
* This licence declaration is applicable when a file states itself to
* be licensed under the GNU GPL; "either version 2 of the License, or
* (at your option) any later version".
*/
#define FILE_LICENCE_GPL2_OR_LATER \
PROVIDE_SYMBOL ( __licence_gpl2_or_later )
/** Declare a file as being under version 2 of the GNU GPL
*
* This licence declaration is applicable when a file states itself to
* be licensed under version 2 of the GPL, and does not include the
* "or, at your option, any later version" clause.
*/
#define FILE_LICENCE_GPL2_ONLY \
PROVIDE_SYMBOL ( __licence_gpl2_only )
/** Declare a file as being under any version of the GNU GPL
*
* This licence declaration is applicable when a file states itself to
* be licensed under the GPL, but does not specify a version.
*
* According to section 9 of the GPLv2, "If the Program does not
* specify a version number of this License, you may choose any
* version ever published by the Free Software Foundation".
*/
#define FILE_LICENCE_GPL_ANY \
PROVIDE_SYMBOL ( __licence_gpl_any )
/** Declare a file as being under the three-clause BSD licence
*
* This licence declaration is applicable when a file states itself to
* be licensed under terms allowing redistribution in source and
* binary forms (with or without modification) provided that:
*
* redistributions of source code retain the copyright notice,
* list of conditions and any attached disclaimers
*
* redistributions in binary form reproduce the copyright notice,
* list of conditions and any attached disclaimers in the
* documentation and/or other materials provided with the
* distribution
*
* the name of the author is not used to endorse or promote
* products derived from the software without specific prior
* written permission
*
* It is not necessary for the file to explicitly state that it is
* under a "BSD" licence; only that the licensing terms be
* functionally equivalent to the standard three-clause BSD licence.
*/
#define FILE_LICENCE_BSD3 \
PROVIDE_SYMBOL ( __licence_bsd3 )
/** Declare a file as being under the two-clause BSD licence
*
* This licence declaration is applicable when a file states itself to
* be licensed under terms allowing redistribution in source and
* binary forms (with or without modification) provided that:
*
* redistributions of source code retain the copyright notice,
* list of conditions and any attached disclaimers
*
* redistributions in binary form reproduce the copyright notice,
* list of conditions and any attached disclaimers in the
* documentation and/or other materials provided with the
* distribution
*
* It is not necessary for the file to explicitly state that it is
* under a "BSD" licence; only that the licensing terms be
* functionally equivalent to the standard two-clause BSD licence.
*/
#define FILE_LICENCE_BSD2 \
PROVIDE_SYMBOL ( __licence_bsd2 )
/** Declare a file as being under the one-clause MIT-style licence
*
* This licence declaration is applicable when a file states itself to
* be licensed under terms allowing redistribution for any purpose
* with or without fee, provided that the copyright notice and
* permission notice appear in all copies.
*/
#define FILE_LICENCE_MIT \
PROVIDE_SYMBOL ( __licence_mit )
/** Declare a particular licence as applying to a file */
#define FILE_LICENCE( _licence ) FILE_LICENCE_ ## _licence
/** @} */
/* This file itself is under GPLv2-or-later */
FILE_LICENCE ( GPL2_OR_LATER );
#include <bits/compiler.h>
#endif /* COMPILER_H */