NAME

clang-local — OpenBSD-specific behavior of LLVM/clang

DESCRIPTION

On OpenBSD, the LLVM/clang compiler exhibits the following characteristics:

clang comes with stack protection enabled by default, equivalent to the -fstack-protector-strong option on other systems. The system will report any violation of the stack protector cookie along with the function name via syslog(3) at LOG_CRIT priority.
clang will generate PIE code by default, allowing the system to load the resulting binary at a random location. This behavior can be turned off by passing -fno-pie to the compiler and -nopie to the linker.
The -fstrict-aliasing option is turned off by default unless -Ofast has been selected.
clang does not store its version string in objects. There is no option to control this.
The -pg flag is an alias of -p.
clang does not warn for passing pointer arguments or assignment with different signedness outside of -pedantic. This can be re-enabled with the -Wpointer-sign flag.
The warning option -Waddress-of-packed-member is disabled by default.
Color diagnostic messages are disabled by default and can be re-enabled with -fdiagnostics-color.
The -fwrapv option to treat signed integer overflows as defined is enabled by default to prevent dangerous optimizations which could remove security critical overflow checks.
The malloc(3), calloc(3), realloc(3), strdup(3), strndup(3), valloc(3) and free(3) builtins are disabled to prevent undesirable optimizations of calls to these functions.