attribute((init_priority(N))) is not codegen'ed properly

[asl]

Bugzilla Link	11480
Resolution	FIXED
Resolved on	Sep 09, 2015 11:53
Version	unspecified
OS	All
CC	@noloader,@kaomoneus

Extended Description

Right now attribute((init_array(N))) in clang defines the "local" order of initialization of statics in the same TU. However, gcc's behavior for init_array(N) is same as for constructor(N) - global priority wrt all TUs.

The solution seems to be easy - instead of emission of the single global initialization function, emit one for each priority and rely on the priorities in the LLVM's global_ctor / global_dtor section. There, if the target supports the ctor / dtor priorities, then everything will be emitted in the appropriate order. Otherwise (e.g. on Darwin, which does not support the priorities), we'll emit everything into the single section with the proper priority order.

Does this sound reasonable?

[asl]

Surely, the attribute is init_priority, not init_array :)

[asl]

*** Bug llvm/llvm-bugzilla-archive#11521 has been marked as a duplicate of this bug. ***

[llvmbot]

As a test case:

--- cls.h ---
#pragma once

#include

class A
{
public:
A() { printf("A::A\n"); }
};

class B
{
public:
B() { printf("B::B\n"); }
};

class C
{
public:
C() { printf("C::C\n"); }
};

--- main.cc ---
#include "cls.h"

A a attribute((init_priority(30000)));

int main()
{
return 0;
}

--- b.cc ---
#include "cls.h"

B b attribute((init_priority(20000)));

--- c.cc ---
#include "cls.h"

C c attribute((init_priority(40000)));

With G++:
$> g++ main.cc b.cc c.cc -o foo
$> ./foo
B::B
A::A
C::C

With Clang++:
(
Debian clang version 3.0-6 (tags/RELEASE_30/final) (based on LLVM 3.0)
Target: i386-pc-linux-gnu
Thread model: posix
)

$> clang++ main.cc b.cc c.cc -o foo
$> ./foo
A::A
B::B
C::C

[kaomoneus]

Proposed patch+test-case to cfe-commits:
http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20120806/062307.html

[asl]

Fixed in r167496

[asl]

mentioned in issue llvm/llvm-bugzilla-archive#11521