[cfe-dev] Q: Custom Assertion Handlers

[Jeffrey Walton]

Hi All,

According to http://clang-analyzer.llvm.org/annotations.html#custom_assertions:

<QUOTE>
void foo(int *p) {
  assert(p != NULL);
}

When this code is preprocessed on Mac OS X it expands to the following:

void foo(int *p) {
  (__builtin_expect(!(p != NULL), 0) ? __assert_rtn(__func__, "t.c",
4, "p != NULL") : (void)0);
}

In this example, the assertion handler is __assert_rtn. When called,
most assertion handlers typically print an error and terminate the
program. The analyzer can exploit such semantics by ending the
analysis of a path once it hits a call to an assertion handler....

The analyzer knows about several well-known assertion handlers, but
can automatically infer if a function should be treated as an
assertion handler if it is annotated with the 'noreturn' attribute or
the (Clang-specific) 'analyzer_noreturn' attribute. Note that,
currently, clang does not support these attributes on Objective-C
methods and C++ methods.
</QUOTE>

I work with source files compiled under a number of compilers,
including GCC, ICC/ICPC, MSVC, and Clang. Some of the compilers don't
support GCC notations.

(1) Is there a way to pass the assertion handler to Clang on the
command line? (I typically use `ASSERT` rather than `assert`).

(2) Is there a way to indicate the failed assertion does *not*
terminate? (Calling abort() is useless behavior during development
(i.e., Debug builds), so my ASSERT raises a SIGTRAP on *nix. Plus,
Release builds don't include 'diagnostics' such as assert, so they are
not present in release builds).

Jeff