cbprintf_internal.h

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/*
 * Copyright (c) 2020 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef ZEPHYR_INCLUDE_SYS_CBPRINTF_INTERNAL_H_
#define ZEPHYR_INCLUDE_SYS_CBPRINTF_INTERNAL_H_
 
#include <errno.h>
#include <stdarg.h>
#include <stddef.h>
#include <stdint.h>
#include <toolchain.h>
#include <sys/util.h>
 
#ifdef CONFIG_CBPRINTF_STATIC_PACKAGE_CHECK_ALIGNMENT
#include <sys/__assert.h>
#endif
 
/*
 * Special alignment cases
 */
 
#if defined(__i386__)
/* there are no gaps on the stack */
#define VA_STACK_ALIGN(type)    1
#elif defined(__sparc__)
/* there are no gaps on the stack */
#define VA_STACK_ALIGN(type)    1
#elif defined(__x86_64__)
#define VA_STACK_MIN_ALIGN      8
#elif defined(__aarch64__)
#define VA_STACK_MIN_ALIGN      8
#elif defined(__riscv)
#define VA_STACK_MIN_ALIGN      (__riscv_xlen / 8)
#endif
 
/*
 * Default alignment values if not specified by architecture config
 */
 
#ifndef VA_STACK_MIN_ALIGN
#define VA_STACK_MIN_ALIGN      1
#endif
 
#ifndef VA_STACK_ALIGN
#define VA_STACK_ALIGN(type)    MAX(VA_STACK_MIN_ALIGN, __alignof__(type))
#endif
 
static inline void z_cbprintf_wcpy(int *dst, int *src, size_t len)
{
        for (size_t i = 0; i < len; i++) {
                dst[i] = src[i];
        }
}
 
#include <sys/cbprintf_cxx.h>
 
#ifdef __cplusplus
extern "C" {
#endif
 
 
#if defined(__sparc__)
/* The SPARC V8 ABI guarantees that the arguments of a variable argument
 * list function are stored on the stack at addresses which are 32-bit
 * aligned. It means that variables of type unit64_t and double may not
 * be properly aligned on the stack.
 *
 * The compiler is aware of the ABI and takes care of this. However,
 * as we are directly accessing the variable argument list here, we need
 * to take the alignment into consideration and copy 64-bit arguments
 * as 32-bit words.
 */
#define Z_CBPRINTF_VA_STACK_LL_DBL_MEMCPY       1
#else
#define Z_CBPRINTF_VA_STACK_LL_DBL_MEMCPY       0
#endif
 
#ifdef __cplusplus
#define Z_CBPRINTF_IS_PCHAR(x) z_cbprintf_cxx_is_pchar(x)
#else
#define Z_CBPRINTF_IS_PCHAR(x) \
        _Generic((x) + 0, \
                char * : 1, \
                const char * : 1, \
                volatile char * : 1, \
                const volatile char * : 1, \
                wchar_t * : 1, \
                const wchar_t * : 1, \
                volatile wchar_t * : 1, \
                const volatile wchar_t * : 1, \
                default : \
                        0)
#endif
 
#define Z_CBPRINTF_HAS_PCHAR_ARGS(fmt, ...) \
        (FOR_EACH(Z_CBPRINTF_IS_PCHAR, (+),  __VA_ARGS__))
 
#if Z_C_GENERIC
#define Z_CBPRINTF_MUST_RUNTIME_PACKAGE(skip, ...) ({\
        _Pragma("GCC diagnostic push") \
        _Pragma("GCC diagnostic ignored \"-Wpointer-arith\"") \
        int _rv = COND_CODE_0(NUM_VA_ARGS_LESS_1(__VA_ARGS__), \
                        (0), \
                        (((Z_CBPRINTF_HAS_PCHAR_ARGS(__VA_ARGS__) - skip) > 0))); \
        _Pragma("GCC diagnostic pop")\
        _rv; \
})
#else
#define Z_CBPRINTF_MUST_RUNTIME_PACKAGE(skip, ...) 1
#endif
 
#ifdef __cplusplus
#define Z_CBPRINTF_ARG_SIZE(v) z_cbprintf_cxx_arg_size(v)
#else
#define Z_CBPRINTF_ARG_SIZE(v) ({\
        __auto_type _v = (v) + 0; \
        size_t _arg_size = _Generic((v), \
                float : sizeof(double), \
                default : \
                        sizeof((_v)) \
                ); \
        _arg_size; \
})
#endif
 
#ifdef __cplusplus
#define Z_CBPRINTF_STORE_ARG(buf, arg) z_cbprintf_cxx_store_arg(buf, arg)
#else
#define Z_CBPRINTF_STORE_ARG(buf, arg) do { \
        if (Z_CBPRINTF_VA_STACK_LL_DBL_MEMCPY) { \
                /* If required, copy arguments by word to avoid unaligned access.*/ \
                __auto_type _v = (arg) + 0; \
                double _d = _Generic((arg) + 0, \
                                float : (arg) + 0, \
                                default : \
                                        0.0); \
                size_t arg_size = Z_CBPRINTF_ARG_SIZE(arg); \
                size_t _wsize = arg_size / sizeof(int); \
                z_cbprintf_wcpy((int *)buf, \
                              (int *) _Generic((arg) + 0, float : &_d, default : &_v), \
                              _wsize); \
        } else { \
                *_Generic((arg) + 0, \
                        char : (int *)buf, \
                        unsigned char: (int *)buf, \
                        short : (int *)buf, \
                        unsigned short : (int *)buf, \
                        int : (int *)buf, \
                        unsigned int : (unsigned int *)buf, \
                        long : (long *)buf, \
                        unsigned long : (unsigned long *)buf, \
                        long long : (long long *)buf, \
                        unsigned long long : (unsigned long long *)buf, \
                        float : (double *)buf, \
                        double : (double *)buf, \
                        long double : (long double *)buf, \
                        default : \
                                (const void **)buf) = arg; \
        } \
} while (0)
#endif
 
#ifdef __cplusplus
#define Z_CBPRINTF_ALIGNMENT(_arg) z_cbprintf_cxx_alignment(_arg)
#else
#define Z_CBPRINTF_ALIGNMENT(_arg) \
        MAX(_Generic((_arg) + 0, \
                float : VA_STACK_ALIGN(double), \
                double : VA_STACK_ALIGN(double), \
                long double : VA_STACK_ALIGN(long double), \
                long long : VA_STACK_ALIGN(long long), \
                unsigned long long : VA_STACK_ALIGN(long long), \
                default : \
                        __alignof__((_arg) + 0)), VA_STACK_MIN_ALIGN)
#endif
 
#ifdef __cplusplus
#if defined(__x86_64__) || defined(__riscv) || defined(__aarch64__)
#define Z_CBPRINTF_IS_LONGDOUBLE(x) 0
#else
#define Z_CBPRINTF_IS_LONGDOUBLE(x) z_cbprintf_cxx_is_longdouble(x)
#endif
#else
#define Z_CBPRINTF_IS_LONGDOUBLE(x) \
        _Generic((x) + 0, long double : 1, default : 0)
#endif
 
#define Z_CBPRINTF_PACK_ARG2(_buf, _idx, _align_offset, _max, \
                             _cfg_flags, _s_idx, _s_buf, _arg) \
do { \
        BUILD_ASSERT(!((sizeof(double) < VA_STACK_ALIGN(long double)) && \
                        Z_CBPRINTF_IS_LONGDOUBLE(_arg) && \
                        !IS_ENABLED(CONFIG_CBPRINTF_PACKAGE_LONGDOUBLE)),\
                        "Packaging of long double not enabled in Kconfig."); \
        while (_align_offset % Z_CBPRINTF_ALIGNMENT(_arg)) { \
                _idx += sizeof(int); \
                _align_offset += sizeof(int); \
        } \
        uint32_t _arg_size = Z_CBPRINTF_ARG_SIZE(_arg); \
        if (Z_CBPRINTF_IS_PCHAR(_arg)) { \
                _s_buf[_s_idx++] = _idx / sizeof(int); \
        } \
        if (_buf && _idx < (int)_max) { \
                Z_CBPRINTF_STORE_ARG(&_buf[_idx], _arg); \
        } \
        _idx += _arg_size; \
        _align_offset += _arg_size; \
} while (0)
 
#define Z_CBPRINTF_PACK_ARG(arg) \
        Z_CBPRINTF_PACK_ARG2(_pbuf, _pkg_len, _pkg_offset, _pmax, _flags, \
                             _s_cnt, _s_buffer, arg)
 
struct z_cbprintf_desc {
        uint8_t len;
        uint8_t str_cnt;
        uint8_t ro_str_cnt;
};
 
union z_cbprintf_hdr {
        struct z_cbprintf_desc desc;
        void *raw;
};
 
/* When using clang additional warning needs to be suppressed since each
 * argument of fmt string is used for sizeof() which results in the warning
 * if argument is a stirng literal. Suppression is added here instead of
 * the macro which generates the warning to not slow down the compiler.
 */
#if __clang__ == 1
#define Z_CBPRINTF_SUPPRESS_SIZEOF_ARRAY_DECAY \
        _Pragma("GCC diagnostic ignored \"-Wsizeof-array-decay\"")
#else
#define Z_CBPRINTF_SUPPRESS_SIZEOF_ARRAY_DECAY
#endif
 
#define Z_CBPRINTF_STATIC_PACKAGE_GENERIC(buf, _inlen, _outlen, _align_offset, \
                                          _flags, ... /* fmt, ... */) \
do { \
        _Pragma("GCC diagnostic push") \
        _Pragma("GCC diagnostic ignored \"-Wpointer-arith\"") \
        Z_CBPRINTF_SUPPRESS_SIZEOF_ARRAY_DECAY \
        BUILD_ASSERT(!IS_ENABLED(CONFIG_XTENSA) || \
                     (IS_ENABLED(CONFIG_XTENSA) && \
                      !(_align_offset % CBPRINTF_PACKAGE_ALIGNMENT)), \
                        "Xtensa requires aligned package."); \
        BUILD_ASSERT((_align_offset % sizeof(int)) == 0, \
                        "Alignment offset must be multiply of a word."); \
        IF_ENABLED(CONFIG_CBPRINTF_STATIC_PACKAGE_CHECK_ALIGNMENT, \
                (__ASSERT(!((uintptr_t)buf & (CBPRINTF_PACKAGE_ALIGNMENT - 1)), \
                          "Buffer must be aligned.");)) \
        bool str_idxs = _flags & CBPRINTF_PACKAGE_ADD_STRING_IDXS; \
        uint8_t *_pbuf = buf; \
        uint8_t _s_cnt = 0; \
        uint16_t _s_buffer[16]; \
        size_t _pmax = (buf != NULL) ? _inlen : INT32_MAX; \
        int _pkg_len = 0; \
        int _total_len = 0; \
        int _pkg_offset = _align_offset; \
        union z_cbprintf_hdr *_len_loc; \
        /* package starts with string address and field with length */ \
        if (_pmax < sizeof(union z_cbprintf_hdr)) { \
                _outlen = -ENOSPC; \
                break; \
        } \
        _len_loc = (union z_cbprintf_hdr *)_pbuf; \
        _pkg_len += sizeof(union z_cbprintf_hdr); \
        _pkg_offset += sizeof(union z_cbprintf_hdr); \
        /* Pack remaining arguments */\
        FOR_EACH(Z_CBPRINTF_PACK_ARG, (;), __VA_ARGS__);\
        _total_len = _pkg_len; \
        if (str_idxs) {\
                _total_len += _s_cnt; \
                if (_pbuf) { \
                        for (int i = 0; i < _s_cnt; i++) { \
                                _pbuf[_pkg_len + i] = _s_buffer[i]; \
                        } \
                } \
        } \
        /* Store length */ \
        _outlen = (_total_len > (int)_pmax) ? -ENOSPC : _total_len; \
        /* Store length in the header, set number of dumped strings to 0 */ \
        if (_pbuf) { \
                union z_cbprintf_hdr hdr = { \
                        .desc = { \
                                .len = (uint8_t)(_pkg_len / sizeof(int)), \
                                .str_cnt = 0, \
                                .ro_str_cnt = str_idxs ? _s_cnt : (uint8_t)0, \
                        } \
                }; \
                *_len_loc = hdr; \
        } \
        _Pragma("GCC diagnostic pop") \
} while (0)
 
#if Z_C_GENERIC
#define Z_CBPRINTF_STATIC_PACKAGE(packaged, inlen, outlen, align_offset, flags, \
                                  ... /* fmt, ... */) \
        Z_CBPRINTF_STATIC_PACKAGE_GENERIC(packaged, inlen, outlen, \
                                          align_offset, flags, __VA_ARGS__)
#else
#define Z_CBPRINTF_STATIC_PACKAGE(packaged, inlen, outlen, align_offset, flags, \
                                  ... /* fmt, ... */) \
do { \
        /* Small trick needed to avoid warning on always true */ \
        if (((uintptr_t)packaged + 1) != 1) { \
                outlen = cbprintf_package(packaged, inlen, flags, __VA_ARGS__); \
        } else { \
                outlen = cbprintf_package(NULL, align_offset, flags, __VA_ARGS__); \
        } \
} while (0)
#endif /* Z_C_GENERIC */
 
#ifdef __cplusplus
}
#endif
 
 
#endif /* ZEPHYR_INCLUDE_SYS_CBPRINTF_INTERNAL_H_ */