On Tuesday, 21 May 2013 at 21:15:58 UTC, Timothee Cour wrote:
I'd like to have the following tools to help with static
analysis & code
coverage:
1) test whether code is reachable or not.
Of course it only works for executables and may have some
caveats (eg:
goto), but its still useful diagnostic tool.
__traits(isReachable): true when the current context can be
reached via at
least one code path starting from main():
----
void fun1(){
//__traits(isReachable) would be false here because even though
fun1 is
called by fun2, it can never be called starting from main().
}
void fun2(){fun1;}
void fun3(){} // would also be false, because of static
if(temp); with temp
being known to be 0 at compile time.
void fun4(){
return;
//__traits(isReachable) would be false here because all code
paths return
above this point.
}
void main(){enum temp=0; static if(temp) fun3; fun4;}
----
When a pointer to a function is taken, we may want to assume by
convention
that __traits(isReachable) is true.
This would enable for example to make sure a given code is
never called.
Note, static assert(0) is not the same.
2)
static code call graph: know caller/calling functions for a
given function.
3) static code coverage
this would allow us to tell at compile time the code coverage
of a module;
it is larger than runtime coverage, but still useful to find
dead code.
It would be very easy to introduce paradoxes if this were
possible, simply use a static if to call something only if it is
unreachable.
