[cfe-dev] Compound Literal semantic analysis...

[Neil Booth]

Steve Naroff wrote:-

> Folks,
> 
> Eli and I have been on improving clang's support for Compound Literals.
> 
> GCC and EDG produce different diagnostics for the following program.
> 
> void a(void) {
> int tmp;
> static int *t = &tmp;        // Both GCC and EDG issue an error  
> diagnostic ("initializer element is not constant").
> static int *a = (int[]){1}; // GCC issues an error diagnostic for this  
> as well (but EDG allows it).
> }
> 
> C99 6.5.2.5p6 says the following:
> 
> The value of the compound literal is that of an unnamed object  
> initialized by the
> initializer list. If the compound literal occurs outside the body of a  
> function, the object
> has static storage duration; otherwise, it has automatic storage  
> duration associated with
> the enclosing block.
> 
> This seems pretty clear to me...GCC is right and EDG is wrong.
> 
> Anyone disagree?

I'm curious about your reasoning.  My front end, which is pretty
good about most things but a tad weak on compuond literals emits:

neil at duron:~/src/c$ ../cfe/cfe /tmp/bug.c 
"/tmp/bug.c", line 3: error: expression must be a constant
static int *t = &tmp;        // Both GCC and EDG issue an error
                ^
"/tmp/bug.c", line 4: warning: declaration hides function "a" declared
at line 1
static int *a = (int[]){1}; // GCC issues an error diagnostic for this
            ^
"/tmp/bug.c", line 3: warning: variable "t" declared but not used
static int *t = &tmp;        // Both GCC and EDG issue an error
            ^
"/tmp/bug.c", line 4: warning: variable "a" declared but not used
static int *a = (int[]){1}; // GCC issues an error diagnostic for this
            ^

1 error found compiling "/tmp/bug.c".

Which agrees with GCC and seems pretty reasonable to me :)

Neil.