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Diffstat (limited to 'clang/docs/LanguageExtensions.rst')
| -rw-r--r-- | clang/docs/LanguageExtensions.rst | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/clang/docs/LanguageExtensions.rst b/clang/docs/LanguageExtensions.rst index af9b61a704e..54f67ce2801 100644 --- a/clang/docs/LanguageExtensions.rst +++ b/clang/docs/LanguageExtensions.rst @@ -1566,6 +1566,49 @@ The complete list of builtins are: unsigned long __builtin_subcl (unsigned long x, unsigned long y, unsigned long carryin, unsigned long *carryout); unsigned long long __builtin_subcll(unsigned long long x, unsigned long long y, unsigned long long carryin, unsigned long long *carryout); +Checked Arithmetic Builtins +--------------------------- + +Clang provides a set of builtins that implement checked arithmetic for security +critical applications in a manner that is fast and easily expressable in C. As +an example of their usage: + +.. code-block:: c + + errorcode_t security_critical_application(...) { + unsigned x, y, result; + ... + if (__builtin_umul_overflow(x, y, &result)) + return kErrorCodeHackers; + ... + use_multiply(result); + ... + } + +A complete enumeration of the builtins are: + +.. code-block:: c + + bool __builtin_uadd_overflow (unsigned x, unsigned y, unsigned *sum); + bool __builtin_uaddl_overflow (unsigned long x, unsigned long y, unsigned long *sum); + bool __builtin_uaddll_overflow(unsigned long long x, unsigned long long y, unsigned long long *sum); + bool __builtin_usub_overflow (unsigned x, unsigned y, unsigned *diff); + bool __builtin_usubl_overflow (unsigned long x, unsigned long y, unsigned long *diff); + bool __builtin_usubll_overflow(unsigned long long x, unsigned long long y, unsigned long long *diff); + bool __builtin_umul_overflow (unsigned x, unsigned y, unsigned *prod); + bool __builtin_umull_overflow (unsigned long x, unsigned long y, unsigned long *prod); + bool __builtin_umulll_overflow(unsigned long long x, unsigned long long y, unsigned long long *prod); + bool __builtin_sadd_overflow (int x, int y, int *sum); + bool __builtin_saddl_overflow (long x, long y, long *sum); + bool __builtin_saddll_overflow(long long x, long long y, long long *sum); + bool __builtin_ssub_overflow (int x, int y, int *diff); + bool __builtin_ssubl_overflow (long x, long y, long *diff); + bool __builtin_ssubll_overflow(long long x, long long y, long long *diff); + bool __builtin_smul_overflow (int x, int y, int *prod); + bool __builtin_smull_overflow (long x, long y, long *prod); + bool __builtin_smulll_overflow(long long x, long long y, long long *prod); + + .. _langext-__c11_atomic: __c11_atomic builtins |
