zephyr/include/toolchain/gcc.h

283 lines
7.7 KiB
C

/* toolchain/gcc.h - GCC toolchain abstraction */
/*
* Copyright (c) 2010-2014 Wind River Systems, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
DESCRIPTION
Macros to abstract compiler capabilities for GCC toolchain.
\NOMANUAL
*/
#include <toolchain/common.h>
#define FUNC_ALIAS(real_func, new_alias, return_type) \
return_type new_alias() __attribute__((alias(#real_func)))
#define _ALIAS_OF(of) __attribute__((alias(#of)))
#define CODE_UNREACHABLE __builtin_unreachable()
#define FUNC_NORETURN __attribute__((__noreturn__))
/* The GNU assembler for Cortex-M3 uses # for immediate values, not
* comments, so the @nobits# trick does not work.
*/
#if defined(CONFIG_ARM)
#define _NODATA_SECTION(segment) __attribute__((section(#segment)))
#else
#define _NODATA_SECTION(segment) \
__attribute__((section(#segment ",\"wa\",@nobits#")))
#endif
/*
* Unaligned reads and writes
*
* To prevent GCC from generating a "breaking strict-aliasing rule" warning,
* use the __may_alias__ attribute to inform it that the pointer may alias
* another type.
*/
#ifdef CONFIG_UNALIGNED_WRITE_UNSUPPORTED
#define UNALIGNED_READ(p) _Unaligned32Read((p))
#define UNALIGNED_WRITE(p, v) \
do { \
unsigned int __attribute__((__may_alias__)) *pp = (unsigned int *)(p); \
_Unaligned32Write(pp, (v)); \
} \
while (0)
#else /* !CONFIG_UNALIGNED_WRITE_UNSUPPORTED */
#define UNALIGNED_READ(p) (*(p))
#define UNALIGNED_WRITE(p, v) \
do { \
unsigned int __attribute__((__may_alias__)) *pp = (unsigned int *)(p); \
*pp = (v); \
} \
while (0)
#endif /* !CONFIG_UNALIGNED_WRITE_UNSUPPORTED */
/* Unaligned access */
#define UNALIGNED_GET(p) \
__extension__ ({ \
struct __attribute__((__packed__)) { \
__typeof__(*(p)) __v; \
} *__p = (__typeof__(__p)) (p); \
__p->__v; \
})
#define _GENERIC_SECTION(segment) __attribute__((section(#segment)))
#define __packed __attribute__((__packed__))
#define __aligned(x) __attribute__((__aligned__(x)))
#define __may_alias __attribute__((__may_alias__))
#define __printf_like(f, a) __attribute__((format (printf, f, a)))
#define __used __attribute__((__used__))
#define ARG_UNUSED(x) (void)(x)
#define likely(x) __builtin_expect((long)!!(x), 1L)
#define unlikely(x) __builtin_expect((long)!!(x), 0L)
/* These macros allow having ARM asm functions callable from thumb */
#if defined(_ASMLANGUAGE) && !defined(_LINKER)
#ifdef CONFIG_ARM
#if defined(CONFIG_ISA_THUMB)
#define FUNC_CODE() \
.code 16; \
.thumb_func;
#define FUNC_INSTR(a) \
BX pc; \
NOP; \
.code 32; \
A##a:
#elif defined(CONFIG_ISA_THUMB2)
#define FUNC_CODE() .thumb;
#define FUNC_INSTR(a)
#elif defined(CONFIG_ISA_ARM)
#define FUNC_CODE() .code 32;
#define FUNC_INSTR(a)
#else
#error unknown instruction set
#endif /* ISA */
#else
#define FUNC_CODE()
#define FUNC_INSTR(a)
#endif /* !CONFIG_ARM */
#endif /* _ASMLANGUAGE && !_LINKER */
/*
* These macros are used to declare assembly language symbols that need
* to be typed properly(func or data) to be visible to the OMF tool.
* So that the build tool could mark them as an entry point to be linked
* correctly. This is an elfism. Use #if 0 for a.out.
*/
#if defined(_ASMLANGUAGE) && !defined(_LINKER)
#ifdef CONFIG_ARM
#define GTEXT(sym) .global FUNC(sym); .type FUNC(sym), %function
#define GDATA(sym) .global FUNC(sym); .type FUNC(sym), %object
#define WTEXT(sym) .weak FUNC(sym); .type FUNC(sym), %function
#define WDATA(sym) .weak FUNC(sym); .type FUNC(sym), %object
#elif defined(CONFIG_ARC)
/*
* Need to use assembly macros because ';' is interpreted as the start of
* a single line comment in the ARC assembler.
*/
.macro glbl_text symbol
.globl FUNC(\symbol)
.type FUNC(\symbol), %function
.endm
.macro glbl_data symbol
.globl FUNC(\symbol)
.type FUNC(\symbol), %object
.endm
#define GTEXT(sym) glbl_text sym
#define GDATA(sym) glbl_data sym
#else /* !CONFIG_ARM && !CONFIG_ARC */
#define GTEXT(sym) .globl FUNC(sym); .type FUNC(sym), @function
#define GDATA(sym) .globl FUNC(sym); .type FUNC(sym), @object
#endif
/*
* These macros specify the section in which a given function or variable
* resides.
*
* - SECTION_FUNC allows only one function to reside in a sub-section
* - SECTION_SUBSEC_FUNC allows multiple functions to reside in a sub-section
* This ensures that garbage collection only discards the section
* if all functions in the sub-section are not referenced.
*/
#if defined(CONFIG_ARC)
/*
* Need to use assembly macros because ';' is interpreted as the start of
* a single line comment in the ARC assembler.
*
* Also, '\()' is needed in the .section directive of these macros for
* correct substitution of the 'section' variable.
*/
.macro section_var section, symbol
.section .\section\().FUNC(\symbol)
FUNC(\symbol) :
.endm
.macro section_func section, symbol
.section .\section\().FUNC(\symbol), "ax"
FUNC_CODE()
PERFOPT_ALIGN
FUNC(\symbol) :
FUNC_INSTR(\symbol)
.endm
.macro section_subsec_func section, subsection, symbol
.section .\section\().\subsection, "ax"
PERFOPT_ALIGN
FUNC(\symbol) :
.endm
#define SECTION_VAR(sect, sym) section_var sect, sym
#define SECTION_FUNC(sect, sym) section_func sect, sym
#define SECTION_SUBSEC_FUNC(sect, subsec, sym) \
section_subsec_func sect, subsec, sym
#else /* !CONFIG_ARC */
#define SECTION_VAR(sect, sym) .section .sect.FUNC(sym); FUNC(sym) :
#define SECTION_FUNC(sect, sym) \
.section .sect.FUNC(sym), "ax"; \
FUNC_CODE() \
PERFOPT_ALIGN; FUNC(sym) : \
FUNC_INSTR(sym)
#define SECTION_SUBSEC_FUNC(sect, subsec, sym) \
.section .sect.subsec, "ax"; PERFOPT_ALIGN; FUNC(sym) :
#endif /* CONFIG_ARC */
#endif /* _ASMLANGUAGE && !_LINKER */
#if defined(CONFIG_ARM) && defined(_ASMLANGUAGE)
#if defined(CONFIG_ISA_THUMB2)
/* '.syntax unified' is a gcc-ism used in thumb-2 asm files */
#define _ASM_FILE_PROLOGUE .text; .syntax unified; .thumb
#elif defined(CONFIG_ISA_THUMB)
#define _ASM_FILE_PROLOGUE .text; .code 16
#else
#define _ASM_FILE_PROLOGUE .text; .code 32
#endif
#endif
/*
* These macros generate absolute symbols for GCC
*/
/* create an extern reference to the absolute symbol */
#define GEN_OFFSET_EXTERN(name) extern const char name[]
#define GEN_ABS_SYM_BEGIN(name) \
extern void name(void); \
void name(void) \
{
#define GEN_ABS_SYM_END }
#if defined(CONFIG_ARM)
/*
* GNU/ARM backend does not have a proper operand modifier which does not
* produces prefix # followed by value, such as %0 for PowerPC, Intel, and
* MIPS. The workaround performed here is using %B0 which converts
* the value to ~(value). Thus "n"(~(value)) is set in operand constraint
* to output (value) in the ARM specific GEN_OFFSET macro.
*/
#define GEN_ABSOLUTE_SYM(name, value) \
__asm__(".globl\t" #name "\n\t.equ\t" #name \
",%B0" \
"\n\t.type\t" #name ",%%object" : : "n"(~(value)))
#elif defined(CONFIG_X86_32) || defined(CONFIG_ARC)
#define GEN_ABSOLUTE_SYM(name, value) \
__asm__(".globl\t" #name "\n\t.equ\t" #name \
",%c0" \
"\n\t.type\t" #name ",@object" : : "n"(value))
#else
#error processor architecture not supported
#endif