llvm dev - Nov 2011 - [LLVMdev] LLVM 3.0 oddity

Hi all,

In the LLVM backend for the DDC compiler, since version 2.7 I have
been doing the following:

  declare external ccc i32 @some_fn(%struct.Obj* ) align 8

  ; bunch more declarations and code.

  define external ccc i32 @some_fn(%struct.Obj*  %_p_vn)  
  {
  entry:

but now I'm getting an error at the function definition saying:

    error: invalid redefinition of function 'some_fn'

So my questions are:

 a) Is this a bug? Should llvm be allowing this?

 b) Is there a good reason why I should not be allowed both declare
    and a defined a function in the same module?

 c) Am I doing something else wrong.

Cheers,
Erik

-- 
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/

Erik de Castro Lopo <mle+cl at mega-nerd.com> writes:

[snip]
>   declare external ccc i32 @some_fn(%struct.Obj* ) align 8
>
>   ; bunch more declarations and code.
>
>   define external ccc i32 @some_fn(%struct.Obj*  %_p_vn)  
[snip]
>  c) Am I doing something else wrong.
I guess that the problem is with the missing `align 8' on the `define'.

Óscar Fuentes wrote:
> Erik de Castro Lopo <mle+cl at mega-nerd.com> writes:
> 
> [snip]
> 
> >   declare external ccc i32 @some_fn(%struct.Obj* ) align 8
> >
> >   ; bunch more declarations and code.
> >
> >   define external ccc i32 @some_fn(%struct.Obj*  %_p_vn)  
> [snip]
> >  c) Am I doing something else wrong.
> 
> I guess that the problem is with the missing `align 8' on the
`define'.
Nope, if I add an 'align 8' to the definition, I still get the
same error.

Here is a minimal test case:

    declare i32 @plus_two(i32)

    define i32 @plus_two(i32 %x) {
      %1 = add nsw i32 %x, 2
      ret i32 %1
    }

for which llc gives the error:


    llc: a.ll:4:12: error: invalid redefinition of function 'plus_two'
    define i32 @plus_two(i32 %x) {



Erik
-- 
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/

On Sun, Nov 27, 2011 at 3:10 PM, Erik de Castro Lopo
<mle+cl at mega-nerd.com>wrote:
>  b) Is there a good reason why I should not be allowed both declare
>    and a defined a function in the same module?
>
I don't know the reason, but I do remember that LLVM does not allow you to
declare a function and define it.

Reid
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Reid Kleckner wrote:
> On Sun, Nov 27, 2011 at 3:10 PM, Erik de Castro Lopo
> <mle+cl at mega-nerd.com>wrote:
> 
> >  b) Is there a good reason why I should not be allowed both declare
> >    and a defined a function in the same module?
> >
> 
> I don't know the reason, but I do remember that LLVM does not allow you
to
> declare a function and define it.
Ok, thanks. I'll have to fix my code generator.

Erik
-- 
----------------------------------------------------------------------
Erik de Castro Lopo
http://www.mega-nerd.com/