[llvm-gcc] Error when an implicitly external function is re-declared as static

[llvmbot]

Bugzilla Link	244
Resolution	FIXED
Resolved on	Feb 22, 2010 12:49
Version	1.0
OS	All
Attachments	C code to reproduce the problem, Incorrect output generated by the test case.
Reporter	LLVM Bugzilla Contributor

Extended Description

The attached code produces a warning with GCC but otherwise produces a single
function defintion.

With LLVM GCC, the attached code generates one function declaration (but no
function definition) and one internal function (which is defined).

[llvmbot]

assigned to @lattner

[llvmbot]

This bug blocks the correct functioning of the espresso Malloc Benchmark.

[lattner]

I love C! :)

[lattner]

FWIW, this is probably related to Bug 232.

[lattner]

Here's another broken testcase:
int one(int a) {
two(a, 5);
return 0;
}

static void two(int a, int b) {}

... in this case, the body of 'two' never gets emitted.

-Chris

[lattner]

Fixed. Here's the (one token) patch:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20040216/011969.html

Testcase here:
test/Regression/CFrontend/2004-02-20-StaticRedeclare.c.tr

It turns out that the second "bad case" that I included in this bug is actually
erroneous C code, so it's not a suprise we don't handle it. :)

-Chris

[lattner]

*** Bug #604 has been marked as a duplicate of this bug. ***

[lattner]

I'm reopening this bug. There seems to be no way to fix both this bug and Bug
276 at the same time.

It appears that the root cause of this bug is internal to the GCC front-end.
This should be revisited for 1.3 when we have hopefully sync'd up with GCC CVS more.

-Chris

[lattner]

Note that this bug is preventing us from being able to compile 134.perl. There
the situation looks like this:

---

static int func();
void bar() {
int func();
foo(func);
}
static int func(char** A, char ** B) {}

Two prototypes with different names are created for 'func'.

-Chris

[llvmbot]

I'm curious. How are the names of the two "func" functions different? Or, did
you mean with different signatures?

[lattner]

The C front-end (buggily) gave the prototype one name ".func_1" and the body
another ".func_2", which the linker, understandably, does not link up.

This is a CFE bug.

-Chris

[lattner]

Fixed. Testcase here:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20041122/021383.html

Patch here:
http://mail.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20041122/021384.html

-Chris

[llvmbot]

mentioned in issue llvm/llvm-bugzilla-archive#33311