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