llvm dev - Apr 2015 - [LLVMdev] what is the Line number of Phi Node with addr2line

Hi, all

   When compiling a program with -g -O0, and if we have a PC, then with
addr2line, we can get the line number of the instruction.

My quesions are:  what is the result of Phi node instruction, can we get
the similar results ?

-- 
Best Regards!
Eric Lew
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Hey Eric,
phi nodes don't exist for real, so you can't.
The are removed by PHI elimination as part of codegen.

What are you trying to achieve?




On Tue, Apr 21, 2015 at 9:12 PM, Eric Lu <eirc.lew at gmail.com>
wrote:
> Hi, all
>
>    When compiling a program with -g -O0, and if we have a PC, then with
> addr2line, we can get the line number of the instruction.
>
> My quesions are:  what is the result of Phi node instruction, can we get
the
> similar results ?
>
> --
> Best Regards!
> Eric Lew
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>

Hi, Daniel

I want to profile load/store operations, in order to reduce the overhead of
profiling, I try to instrument the optimized llvm ir, which has phi nodes.

BTW, when the value of some load/store operations may have multi-source,
then the load will be translated into phi nodes, and all phi nodes are
placed in the front of BB. Sometimes, the position is not where the load
happens, is there any way to figure out where the load should be placed?(
If the phi node translated back to load operations)

Best Regards!
Eric Lew
On 周三, 4月 22, 2015 at 12:24 下午, Daniel Berlin <dberlin at dberlin.org>
wrote:

Hey Eric,
phi nodes don't exist for real, so you can't.
The are removed by PHI elimination as part of codegen.

What are you trying to achieve?




On Tue, Apr 21, 2015 at 9:12 PM, Eric Lu <eirc.lew at gmail.com>
wrote:
> Hi, all
>
>    When compiling a program with -g -O0, and if we have a PC, then with
> addr2line, we can get the line number of the instruction.
>
> My quesions are:  what is the result of Phi node instruction, can we get
the
> similar results ?
>
> --
> Best Regards!
> Eric Lew
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
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