/* Copyright (c) 2003-2004, Roger Dingledine * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson. * Copyright (c) 2007-2018, The Tor Project, Inc. */ /* See LICENSE for licensing information */ #ifndef TOR_COMPAT_COMPILER_H #define TOR_COMPAT_COMPILER_H #include "orconfig.h" #include #if defined(__has_feature) # if __has_feature(address_sanitizer) /* Some of the fancy glibc strcmp() macros include references to memory that * clang rejects because it is off the end of a less-than-3. Clang hates this, * even though those references never actually happen. */ # undef strcmp #endif /* __has_feature(address_sanitizer) */ #endif /* defined(__has_feature) */ #ifndef NULL_REP_IS_ZERO_BYTES #error "It seems your platform does not represent NULL as zero. We can't cope." #endif #ifndef DOUBLE_0_REP_IS_ZERO_BYTES #error "It seems your platform does not represent 0.0 as zeros. We can't cope." #endif #if 'a'!=97 || 'z'!=122 || 'A'!=65 || ' '!=32 #error "It seems that you encode characters in something other than ASCII." #endif /* GCC can check printf and scanf types on arbitrary functions. */ #ifdef __GNUC__ #define CHECK_PRINTF(formatIdx, firstArg) \ __attribute__ ((format(printf, formatIdx, firstArg))) #else #define CHECK_PRINTF(formatIdx, firstArg) #endif /* defined(__GNUC__) */ #ifdef __GNUC__ #define CHECK_SCANF(formatIdx, firstArg) \ __attribute__ ((format(scanf, formatIdx, firstArg))) #else #define CHECK_SCANF(formatIdx, firstArg) #endif /* defined(__GNUC__) */ /* What GCC do we have? */ #ifdef __GNUC__ #define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__) #else #define GCC_VERSION 0 #endif /* Temporarily enable and disable warnings. */ #ifdef __GNUC__ # define PRAGMA_STRINGIFY_(s) #s # define PRAGMA_JOIN_STRINGIFY_(a,b) PRAGMA_STRINGIFY_(a ## b) /* Support for macro-generated pragmas (c99) */ # define PRAGMA_(x) _Pragma (#x) # ifdef __clang__ # define PRAGMA_DIAGNOSTIC_(x) PRAGMA_(clang diagnostic x) # else # define PRAGMA_DIAGNOSTIC_(x) PRAGMA_(GCC diagnostic x) # endif # if defined(__clang__) || GCC_VERSION >= 406 /* we have push/pop support */ # define DISABLE_GCC_WARNING(warningopt) \ PRAGMA_DIAGNOSTIC_(push) \ PRAGMA_DIAGNOSTIC_(ignored PRAGMA_JOIN_STRINGIFY_(-W,warningopt)) # define ENABLE_GCC_WARNING(warningopt) \ PRAGMA_DIAGNOSTIC_(pop) #else /* !(defined(__clang__) || GCC_VERSION >= 406) */ /* older version of gcc: no push/pop support. */ # define DISABLE_GCC_WARNING(warningopt) \ PRAGMA_DIAGNOSTIC_(ignored PRAGMA_JOIN_STRINGIFY_(-W,warningopt)) # define ENABLE_GCC_WARNING(warningopt) \ PRAGMA_DIAGNOSTIC_(warning PRAGMA_JOIN_STRINGIFY_(-W,warningopt)) #endif /* defined(__clang__) || GCC_VERSION >= 406 */ #else /* !(defined(__GNUC__)) */ /* not gcc at all */ # define DISABLE_GCC_WARNING(warning) # define ENABLE_GCC_WARNING(warning) #endif /* defined(__GNUC__) */ /* inline is __inline on windows. */ #ifdef _WIN32 #define inline __inline #endif /* Try to get a reasonable __func__ substitute in place. */ #if defined(_MSC_VER) #define __func__ __FUNCTION__ #else /* For platforms where autoconf works, make sure __func__ is defined * sanely. */ #ifndef HAVE_MACRO__func__ #ifdef HAVE_MACRO__FUNCTION__ #define __func__ __FUNCTION__ #elif HAVE_MACRO__FUNC__ #define __func__ __FUNC__ #else #define __func__ "???" #endif /* defined(HAVE_MACRO__FUNCTION__) || ... */ #endif /* !defined(HAVE_MACRO__func__) */ #endif /* defined(_MSC_VER) */ #ifdef ENUM_VALS_ARE_SIGNED #define ENUM_BF(t) unsigned #else /** Wrapper for having a bitfield of an enumerated type. Where possible, we * just use the enumerated type (so the compiler can help us and notice * problems), but if enumerated types are unsigned, we must use unsigned, * so that the loss of precision doesn't make large values negative. */ #define ENUM_BF(t) t #endif /* defined(ENUM_VALS_ARE_SIGNED) */ /* GCC has several useful attributes. */ #if defined(__GNUC__) && __GNUC__ >= 3 #define ATTR_NORETURN __attribute__((noreturn)) #define ATTR_CONST __attribute__((const)) #define ATTR_MALLOC __attribute__((malloc)) #define ATTR_NORETURN __attribute__((noreturn)) #define ATTR_WUR __attribute__((warn_unused_result)) #define ATTR_UNUSED __attribute__ ((unused)) /** Macro: Evaluates to exp and hints the compiler that the value * of exp will probably be true. * * In other words, "if (PREDICT_LIKELY(foo))" is the same as "if (foo)", * except that it tells the compiler that the branch will be taken most of the * time. This can generate slightly better code with some CPUs. */ #define PREDICT_LIKELY(exp) __builtin_expect(!!(exp), 1) /** Macro: Evaluates to exp and hints the compiler that the value * of exp will probably be false. * * In other words, "if (PREDICT_UNLIKELY(foo))" is the same as "if (foo)", * except that it tells the compiler that the branch will usually not be * taken. This can generate slightly better code with some CPUs. */ #define PREDICT_UNLIKELY(exp) __builtin_expect(!!(exp), 0) #else /* !(defined(__GNUC__) && __GNUC__ >= 3) */ #define ATTR_NORETURN #define ATTR_CONST #define ATTR_MALLOC #define ATTR_NORETURN #define ATTR_UNUSED #define ATTR_WUR #define PREDICT_LIKELY(exp) (exp) #define PREDICT_UNLIKELY(exp) (exp) #endif /* defined(__GNUC__) && __GNUC__ >= 3 */ /** Expands to a syntactically valid empty statement. */ #define STMT_NIL (void)0 /** Expands to a syntactically valid empty statement, explicitly (void)ing its * argument. */ #define STMT_VOID(a) while (0) { (void)(a); } #ifdef __GNUC__ /** STMT_BEGIN and STMT_END are used to wrap blocks inside macros so that * the macro can be used as if it were a single C statement. */ #define STMT_BEGIN (void) ({ #define STMT_END }) #elif defined(sun) || defined(__sun__) #define STMT_BEGIN if (1) { #define STMT_END } else STMT_NIL #else #define STMT_BEGIN do { #define STMT_END } while (0) #endif /* defined(__GNUC__) || ... */ /* Some tools (like coccinelle) don't like to see operators as macro * arguments. */ #define OP_LT < #define OP_GT > #define OP_GE >= #define OP_LE <= #define OP_EQ == #define OP_NE != #if defined(__MINGW32__) || defined(__MINGW64__) #define MINGW_ANY #endif /** Macro: yield a pointer to the field at position off within the * structure st. Example: * 
 *   struct a { int foo; int bar; } x;
 *   off_t bar_offset = offsetof(struct a, bar);
 *   int *bar_p = STRUCT_VAR_P(&x, bar_offset);
 *   *bar_p = 3;
 *
*/ #define STRUCT_VAR_P(st, off) ((void*) ( ((char*)(st)) + (off) ) ) /** Macro: yield a pointer to an enclosing structure given a pointer to * a substructure at offset off. Example: * 
 *   struct base { ... };
 *   struct subtype { int x; struct base b; } x;
 *   struct base *bp = &x.base;
 *   struct *sp = SUBTYPE_P(bp, struct subtype, b);
 *
*/ #define SUBTYPE_P(p, subtype, basemember) \ ((void*) ( ((char*)(p)) - offsetof(subtype, basemember) )) /** Macro: Yields the number of elements in array x. */ #define ARRAY_LENGTH(x) ((sizeof(x)) / sizeof(x[0])) #endif /* !defined(TOR_COMPAT_H) */