1 /* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ 2 #ifndef PLDM_COMPILER_H 3 #define PLDM_COMPILER_H 4 5 #include <libpldm/compiler.h> 6 7 #ifndef __has_attribute 8 #error The libpldm implementation requires __has_attribute 9 #endif 10 11 #include <assert.h> 12 13 static struct { 14 static_assert(__has_attribute(always_inline), 15 "`always_inline` attribute is required"); 16 static_assert(__has_attribute(cleanup), 17 "`cleanup` attribute is required"); 18 static_assert(__has_attribute(nonnull), 19 "`nonnull` attribute is required"); 20 static_assert(__has_attribute(unused), 21 "`unused` attribute is required"); 22 static_assert(__has_attribute(warn_unused_result), 23 "`warn_unused_result` attribute is required"); 24 static_assert(__has_attribute(weak), "`weak` attribute is required"); 25 int compliance; 26 } pldm_required_attributes __attribute__((unused)); 27 28 #ifndef LIBPLDM_CC_ALWAYS_INLINE 29 #error Missing definition for LIBPLDM_ALWAYS_INLINE 30 #endif 31 32 #ifndef LIBPLDM_CC_NONNULL 33 #error Missing definition for LIBPLDM_CC_NONNULL 34 #endif 35 36 #define LIBPLDM_CC_CLEANUP(fn) __attribute__((cleanup(fn))) 37 #define LIBPLDM_CC_NONNULL_ARGS(...) __attribute__((nonnull(__VA_ARGS__))) 38 #define LIBPLDM_CC_UNUSED __attribute__((unused)) 39 #define LIBPLDM_CC_WARN_UNUSED_RESULT __attribute__((warn_unused_result)) 40 #define LIBPLDM_CC_WEAK __attribute__((weak)) 41 42 // NOLINTBEGIN(bugprone-macro-parentheses) 43 /** 44 * Require that the given object is of the specified type. 45 * 46 * If the object is not of the required type then a diagnostic will be emitted. 47 * 48 * If you are reading this documentation due to hitting a compilation error 49 * passing through the macro, then you have a type error in your code that must 50 * be fixed. Despite the compiler output, the error is _not_ that some array 51 * is negatively sized, the array is negatively sized _because_ you have a type 52 * error. 53 * 54 * How this works: 55 * 56 * If the type of @p obj is not equivalent to the provided type @p type then 57 * we force the compiler to evaluate sizeof on a negatively-sized array. The 58 * C standard requires that the integer constant expression that specifies 59 * the array length must be greater than zero. Failure to meet this constraint 60 * generally terminates compilation of the translation unit as any other result 61 * cannot be handled in a sensible way. The array size is derived to an integer 62 * constant expression from a type eqivalence evaluated using _Generic() 63 * allowing us to stay within the language standard. The default generic 64 * association, representing a type mismatch, yields -1. 65 * 66 * pldm_require_obj_type() was introduced into the libpldm implementation to 67 * enable use of the pldm_msgbuf_extract*() APIs for objects that may or may not 68 * reside in a packed struct. See src/msgbuf.h for more details. 69 * 70 * @param obj The name of the object to evaluate 71 * @param type The required type of @p obj 72 * 73 * @return The expression either yields 1, or compilation is terminated 74 */ 75 #define pldm_require_obj_type(obj, type) \ 76 ((void)(sizeof( \ 77 struct { char buf[_Generic((obj), type: 1, default: -1)]; }))) 78 // NOLINTEND(bugprone-macro-parentheses) 79 80 #endif 81