llvm dev - Jun 2009 - [LLVMdev] debug information for functions

Suppose I have fun.h as:

 

static  void fun() {

  int a =10;

}

 

Now I have two files foo.c and goo.c as 

foo.c :

#include "fun.h"

void foo() 

{

  fun();

}

 

goo.c:

#include "fun.h"

void goo()

{

  fun();

}

 

I get .bc files for foo.c and foo.bc through clang. Now I run llvm-ld
with -disable-opt for foo.bc and goo.bc. In the resulting .bc files, one
of the two functions fun, is renamed to fun<number>. There are two
llvm.dbg.subprogram descriptors created for the two fun functions. Both
have name foo . So there is no way to know which descriptor represents
which function. I am trying to get this information in assembly printer.

 


Proposed solution :  llvm.dbg.subprogram.type should have a reference to
function is represents. This is in the same way as
llvm.dbg.global_variable.type has a reference to global variable it
represents.

 

Thanks

Vasudev

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I would assume this is similar to the problem of dealing with structure
tags, and I guess your proposal is along lines of the same solution
right? 

 

A.

 

________________________________

From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
On Behalf Of Vasudev.Negi at microchip.com
Sent: Monday, June 08, 2009 3:25 AM
To: llvmdev at cs.uiuc.edu
Subject: debug information for functions

 

Suppose I have fun.h as:

 

static  void fun() {

  int a =10;

}

 

Now I have two files foo.c and goo.c as 

foo.c :

#include "fun.h"

void foo() 

{

  fun();

}

 

goo.c:

#include "fun.h"

void goo()

{

  fun();

}

 

I get .bc files for foo.c and foo.bc through clang. Now I run llvm-ld
with -disable-opt for foo.bc and goo.bc. In the resulting .bc files, one
of the two functions fun, is renamed to fun<number>. There are two
llvm.dbg.subprogram descriptors created for the two fun functions. Both
have name foo . So there is no way to know which descriptor represents
which function. I am trying to get this information in assembly printer.

 


Proposed solution :  llvm.dbg.subprogram.type should have a reference to
function is represents. This is in the same way as
llvm.dbg.global_variable.type has a reference to global variable it
represents.

 

Thanks

Vasudev

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On Mon, Jun 8, 2009 at 3:25 AM, <Vasudev.Negi at microchip.com>
wrote:
>
> I get .bc files for foo.c and foo.bc through clang. Now I run llvm-ld
> with -disable-opt for foo.bc and goo.bc. In the resulting .bc files, one
> of the two functions fun, is renamed to fun<number>. There are two
> llvm.dbg.subprogram descriptors created for the two fun functions. Both
> have name foo . So there is no way to know which descriptor represents
> which function. I am trying to get this information in assembly printer.
What is the use of this info ? The descriptor includes enough location
info (thru func.start) and the display name for static functions.

-
Devang

-----Original Message-----
From: llvmdev-bounces at cs.uiuc.edu [mailto:llvmdev-bounces at cs.uiuc.edu]
On Behalf Of Devang Patel
Sent: Monday, June 08, 2009 11:03 PM
To: LLVM Developers Mailing List
Subject: Re: [LLVMdev] debug information for functions

On Mon, Jun 8, 2009 at 3:25 AM, <Vasudev.Negi at microchip.com>
wrote:
>
> I get .bc files for foo.c and foo.bc through clang. Now I run llvm-ld
> with -disable-opt for foo.bc and goo.bc. In the resulting .bc files,
one
> of the two functions fun, is renamed to fun<number>. There are two
> llvm.dbg.subprogram descriptors created for the two fun functions.
Both
> have name foo . So there is no way to know which descriptor represents
> which function. I am trying to get this information in assembly
printer.

What is the use of this info ? The descriptor includes enough location
info (thru func.start) and the display name for static functions.

-
Devang

We are not using Dwarf writer. We are emitting debug info in coff
format. I need the file in which function is defined to emit .file
directive. MachineFunction has DefaultDebugLoc but it gets set only in
the case of -O0.
I can get the DebugLoc from machine instruction but that will be an ugly
way to do it.