libc/src/__support/libc_assert.h

   1 //===-- Definition of a libc internal assert macro --------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef LLVM_LIBC_SRC___SUPPORT_LIBC_ASSERT_H
  10 #define LLVM_LIBC_SRC___SUPPORT_LIBC_ASSERT_H
  11
  12 #include "src/__support/macros/config.h"
  13 #if defined(LIBC_COPT_USE_C_ASSERT) || !defined(LIBC_FULL_BUILD)
  14
  15 // The build is configured to just use the public <assert.h> API
  16 // for libc's internal assertions.
  17
  18 #include <assert.h>
  19
  20 #define LIBC_ASSERT(COND) assert(COND)
  21
  22 #else // Not LIBC_COPT_USE_C_ASSERT
  23
  24 #include "src/__support/OSUtil/exit.h"
  25 #include "src/__support/OSUtil/io.h"
  26 #include "src/__support/integer_to_string.h"
  27 #include "src/__support/macros/attributes.h"   // For LIBC_INLINE
  28 #include "src/__support/macros/optimization.h" // For LIBC_UNLIKELY
  29
  30 namespace LIBC_NAMESPACE_DECL {
  31
  32 // This is intended to be removed in a future patch to use a similar design to
  33 // below, but it's necessary for the external assert.
  34 LIBC_INLINE void report_assertion_failure(const char *assertion,
  35                                           const char *filename, unsigned line,
  36                                           const char *funcname) {
  37   const IntegerToString<unsigned> line_buffer(line);
  38   write_to_stderr(filename);
  39   write_to_stderr(":");
  40   write_to_stderr(line_buffer.view());
  41   write_to_stderr(": Assertion failed: '");
  42   write_to_stderr(assertion);
  43   write_to_stderr("' in function: '");
  44   write_to_stderr(funcname);
  45   write_to_stderr("'\n");
  46 }
  47
  48 } // namespace LIBC_NAMESPACE_DECL
  49
  50 #ifdef LIBC_ASSERT
  51 #error "Unexpected: LIBC_ASSERT macro already defined"
  52 #endif
  53
  54 // The public "assert" macro calls abort on failure. Should it be same here?
  55 // The libc internal assert can fire from anywhere inside the libc. So, to
  56 // avoid potential chicken-and-egg problems, it is simple to do an exit
  57 // on assertion failure instead of calling abort. We also don't want to use
  58 // __builtin_trap as it could potentially be implemented using illegal
  59 // instructions which can be very misleading when debugging.
  60 #ifdef NDEBUG
  61 #define LIBC_ASSERT(COND)                                                      \
  62   do {                                                                         \
  63   } while (false)
  64 #else
  65
  66 // Convert __LINE__ to a string using macros. The indirection is necessary
  67 // because otherwise it will turn "__LINE__" into a string, not its value. The
  68 // value is evaluated in the indirection step.
  69 #define __LIBC_MACRO_TO_STR(x) #x
  70 #define __LIBC_MACRO_TO_STR_INDIR(y) __LIBC_MACRO_TO_STR(y)
  71 #define __LIBC_LINE_STR__ __LIBC_MACRO_TO_STR_INDIR(__LINE__)
  72
  73 #define LIBC_ASSERT(COND)                                                      \
  74   do {                                                                         \
  75     if (LIBC_UNLIKELY(!(COND))) {                                              \
  76       LIBC_NAMESPACE::write_to_stderr(__FILE__ ":" __LIBC_LINE_STR__           \
  77                                                ": Assertion failed: '" #COND   \
  78                                                "' in function: '");            \
  79       LIBC_NAMESPACE::write_to_stderr(__PRETTY_FUNCTION__);                    \
  80       LIBC_NAMESPACE::write_to_stderr("'\n");                                  \
  81       LIBC_NAMESPACE::internal::exit(0xFF);                                    \
  82     }                                                                          \
  83   } while (false)
  84 #endif // NDEBUG
  85
  86 #endif // LIBC_COPT_USE_C_ASSERT
  87
  88 #endif // LLVM_LIBC_SRC___SUPPORT_LIBC_ASSERT_H