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Chuck Zhao

2011-May-09 14:54 UTC

[LLVMdev] <badref> showed up when duplicating a list of dependent instructions

I collected a sequence of LLVM instructions, want to make a copy of each 
and insert them into a PREVIOUS location inside the same function (all 
globals and locals are properly declared before the PREVIOUS location).

Here is the list of instructions I want to duplicate and insert:

0    %90 = load i32* @strstart, align 4
1    %91 = add i32 %90, 2
2    %88 = load i32* @ins_h, align 4
3    %92 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %91
4    %89 = shl i32 %88, 5
5    %93 = load i8* %92, align 1
6    %.masked = and i32 %89, 32736
7    %94 = zext i8 %93 to i32
8    %95 = xor i32 %94, %.masked
9    %.sum73 = or i32 %95, 32768
10    %104 = getelementptr inbounds [65536 x i16]* @prev, i32 0, i32 %.sum73
11    %take_addr2 = getelementptr i16* %104
12    %105 = bitcast i16* %take_addr2 to i8*
13    call void @bkp_memory(i8* %105, i32 2)

{basically, I want to duplicate the bkp_memory() call, everything else 
are its dependent instructions.}

I put them into a std::vector<Instruction *> coll, with the following 
code trying to do the replication and insertion:

std::vector<Instruction *>::iterator p;
Instruction * pi = PREVIOUS_POSITION;
BasicBlock * pb = PREVIOUS_POSITION->getParent();

for(p = coll.begin(); p != coll.end(); ++p){
    Instruction * CurI = * p;
    Instruction * CloneI = CurI->clone();
    CloneI->setName(CurI->getName());
    errs() << *CloneI << "\n";
    pb->getInstList().insertAfter(pi, CloneI); // Inserts newInst after 
pi in pb

    // adjust pi: point to the newly inserted inst:
    pi = CurI;

}//end of for loop on p


However, I got the following errors:

--- Insert New (cloned) Instructions: ...
   <badref>  = load i32* @strstart, align 4
   <badref>  = add i32<badref>, 2
   <badref>  = load i32* @ins_h, align 4
   <badref>  = getelementptr inbounds [65536 x i8]* @window, i32 0,
i32<badref>
   <badref>  = shl i32<badref>, 5
   <badref>  = load i8*<badref>, align 1
   %.masked = and i32<badref>, 32736
   <badref>  = zext i8<badref>  to i32
   <badref>  = xor i32<badref>, %.masked
   %.sum73 = or i32<badref>, 32768
   <badref>  = getelementptr inbounds [65536 x i16]* @prev, i32 0, i32
%.sum73
   %take_addr2 = getelementptr i16*<badref>
   <badref>  = bitcast i16* %take_addr2 to i8*
   call void @bkp_memory(i8*<badref>, i32 2)
Instruction does not dominate all uses!
   %95 = add i32 %93, 2
   %90 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
Instruction does not dominate all uses!
   %97 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
   %92 = load i8* %97, align 1
Instruction does not dominate all uses!
   %.masked = and i32 %91, 32736
   %101 = xor i32 %100, %.masked
Broken module found, compilation aborted!


What am I doing wrong here?
Does the<badref>  sound alarm to anyone?
What is the right approach I should take here?


Thank you very much

Chuck




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Duncan Sands

2011-May-09 15:13 UTC

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[LLVMdev] <badref> showed up when duplicating a list of dependent instructions

Hi Chuck,
> std::vector<Instruction *>::iterator p;
> Instruction * pi = PREVIOUS_POSITION;
> BasicBlock * pb = PREVIOUS_POSITION->getParent();
>
> for(p = coll.begin(); p != coll.end(); ++p){
> Instruction * CurI = * p;
> Instruction * CloneI = CurI->clone();
clone doesn't know have any magical way of knowing that it should update the
instruction's operands to point to the clone you created earlier.  For
example,
consider

  %l = load i32* @ins_h, align 4
  %s = shl i32 %l, 5

You clone %l, getting:
   %lc = load i32* @ins_h, align 4
You clone %s, getting:
   %sc = shl i32 %l, 5
But %sc still has %l as an operand.  You want it to have %lc as an
operand, which requires doing more.

Ciao, Duncan.
> CloneI->setName(CurI->getName());
> errs() << *CloneI << "\n";
> pb->getInstList().insertAfter(pi, CloneI); // Inserts newInst after pi
in pb
>
> // adjust pi: point to the newly inserted inst:
> pi = CurI;
>
> }//end of for loop on p
>
>
> However, I got the following errors:
>
> --- Insert New (cloned) Instructions: ...
>     <badref>   = load i32* @strstart, align 4
>    <badref>  = add i32<badref>, 2
>    <badref>  = load i32* @ins_h, align 4
>    <badref>  = getelementptr inbounds [65536 x i8]* @window, i32 0,
i32<badref>
>    <badref>  = shl i32<badref>, 5
>    <badref>  = load i8*<badref>, align 1
>    %.masked = and i32<badref>, 32736
>    <badref>  = zext i8<badref>  to i32
>    <badref>  = xor i32<badref>, %.masked
>    %.sum73 = or i32<badref>, 32768
>    <badref>  = getelementptr inbounds [65536 x i16]* @prev, i32 0,
i32 %.sum73
>    %take_addr2 = getelementptr i16*<badref>
>    <badref>  = bitcast i16* %take_addr2 to i8*
>    call void @bkp_memory(i8*<badref>, i32 2)
> Instruction does not dominate all uses!
>    %95 = add i32 %93, 2
>    %90 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
> Instruction does not dominate all uses!
>    %97 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
>    %92 = load i8* %97, align 1
> Instruction does not dominate all uses!
>    %.masked = and i32 %91, 32736
>    %101 = xor i32 %100, %.masked
> Broken module found, compilation aborted!
>
>
> What am I doing wrong here?
> Does the<badref>  sound alarm to anyone?
> What is the right approach I should take here?
>
>
> Thank you very much
>
> Chuck
>
>
>
>
>
>
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev

Chuck Zhao

2011-May-09 15:21 UTC

head link

[LLVMdev] <badref> showed up when duplicating a list of dependent instructions

Duncan,

I see.
Seems the per-operand value mapping is also needed, and is currently 
missing.

Thank you

Chuck

On 5/9/2011 11:13 AM, Duncan Sands wrote:> Hi Chuck,
>
>> std::vector<Instruction *>::iterator p;
>> Instruction * pi = PREVIOUS_POSITION;
>> BasicBlock * pb = PREVIOUS_POSITION->getParent();
>>
>> for(p = coll.begin(); p != coll.end(); ++p){
>> Instruction * CurI = * p;
>> Instruction * CloneI = CurI->clone();
> clone doesn't know have any magical way of knowing that it should
update the
> instruction's operands to point to the clone you created earlier.  For
example,
> consider
>
>    %l = load i32* @ins_h, align 4
>    %s = shl i32 %l, 5
>
> You clone %l, getting:
>     %lc = load i32* @ins_h, align 4
> You clone %s, getting:
>     %sc = shl i32 %l, 5
> But %sc still has %l as an operand.  You want it to have %lc as an
> operand, which requires doing more.
>
> Ciao, Duncan.
>
>> CloneI->setName(CurI->getName());
>> errs()<<  *CloneI<<  "\n";
>> pb->getInstList().insertAfter(pi, CloneI); // Inserts newInst after
pi in pb
>>
>> // adjust pi: point to the newly inserted inst:
>> pi = CurI;
>>
>> }//end of for loop on p
>>
>>
>> However, I got the following errors:
>>
>> --- Insert New (cloned) Instructions: ...
>>      <badref>    = load i32* @strstart, align 4
>>     <badref>   = add i32<badref>, 2
>>     <badref>   = load i32* @ins_h, align 4
>>     <badref>   = getelementptr inbounds [65536 x i8]* @window,
i32 0, i32<badref>
>>     <badref>   = shl i32<badref>, 5
>>     <badref>   = load i8*<badref>, align 1
>>     %.masked = and i32<badref>, 32736
>>     <badref>   = zext i8<badref>   to i32
>>     <badref>   = xor i32<badref>, %.masked
>>     %.sum73 = or i32<badref>, 32768
>>     <badref>   = getelementptr inbounds [65536 x i16]* @prev, i32
0, i32 %.sum73
>>     %take_addr2 = getelementptr i16*<badref>
>>     <badref>   = bitcast i16* %take_addr2 to i8*
>>     call void @bkp_memory(i8*<badref>, i32 2)
>> Instruction does not dominate all uses!
>>     %95 = add i32 %93, 2
>>     %90 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
>> Instruction does not dominate all uses!
>>     %97 = getelementptr inbounds [65536 x i8]* @window, i32 0, i32 %95
>>     %92 = load i8* %97, align 1
>> Instruction does not dominate all uses!
>>     %.masked = and i32 %91, 32736
>>     %101 = xor i32 %100, %.masked
>> Broken module found, compilation aborted!
>>
>>
>> What am I doing wrong here?
>> Does the<badref>   sound alarm to anyone?
>> What is the right approach I should take here?
>>
>>
>> Thank you very much
>>
>> Chuck
>>
>>
>>
>>
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> _______________________________________________
> 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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