[LLVMdev] Local variable information in scope

[Eric Christopher]

With ToT clang I get output that looks something like this:

0x00000051:     TAG_subprogram [2] *
                 AT_sibling( {0x000000be} )
                 AT_name( "func" )
                 AT_decl_file( "/Users/echristo/bar.c" )
                 AT_decl_line( 2 )
                 AT_prototyped( 0x01 )
                 AT_type( {0x000000be} ( int ) )
                 AT_external( 0x01 )
                 AT_low_pc( 0x0000000000000000 )
                 AT_high_pc( 0x0000000000000017 )
                 AT_frame_base( rbp )

0x00000075:         TAG_formal_parameter [3]  
                     AT_name( "t" )
                     AT_decl_file( "/Users/echristo/bar.c" )
                     AT_decl_line( 1 )
                     AT_type( {0x000000be} ( int ) )
                     AT_location( fbreg -4 )

0x00000081:         TAG_lexical_block [4] *
                     AT_low_pc( 0x0000000000000007 )
                     AT_high_pc( 0x0000000000000017 )

0x00000092:             TAG_variable [5]  
                         AT_name( "x" )
                         AT_decl_file( "/Users/echristo/bar.c" )
                         AT_decl_line( 3 )
                         AT_type( {0x000000be} ( int ) )
                         AT_location( fbreg -8 )

0x0000009e:             TAG_lexical_block [4] *
                         AT_low_pc( 0x0000000000000007 )
                         AT_high_pc( 0x0000000000000012 )

0x000000af:                 TAG_variable [5]  
                             AT_name( "a" )
                             AT_decl_file( "/Users/echristo/bar.c" )
                             AT_decl_line( 6 )
                             AT_type( {0x000000be} ( int ) )
                             AT_location( fbreg -12 )

using your test case from below slightly modified to make sure that a was actually used.

Which appears to be exactly what you were looking for? And yes, it matches the dbg.declare instruction.

-eric

On Oct 13, 2011, at 1:43 AM, Pankaj Gode wrote:

> 
> Hi,
>  
> I want to list some additional information on this.
>  
> The variable collection I am looking at is, "variables 'declared' in scope".
>  
> 1. When I traverse the MachineInstructions in the LexicalScopes ranges, and check for variables, I get variables used in this scope.  
>    The variables listed include variables which may not have been declared in the scope. (for example "int t", which is not declared in scope1, is listed.)
>    I do this by checking if the instruction uses memoperands then I collect name of value.
>  
> So, for the example below
> int func( int t)
> { 
>   int x;
>   //scope 1
>   {
>      int a;
>      ....
>   }
>   return x;
> }
>  
> what I am expecting is as below:
> <scope name>: <list of variables declared in scope>
> func scope: t, x
> scope 1: a
>   
>  
> 2. I checked the "CodeGen/AsmPrinter/DwarfDebug.cpp" as reference, to find mapping of "MachineInstruction" to "llvm.dbg.declare", to extract variables declared in scope.
>  
> I am not sure whether there is any other way to get to variables declared in scope.
>  
>  
> Regards,
> Pankaj
>  
>  
> On Oct 12, 2011, at 3:14 AM, Pankaj Gode wrote:
> 
>> Hi all,
>>  
>> Using "CodeGen/LexicalScopes" pass, I could collect scope information i.e. start and end line numbers.
>>  
>> I also want to collect information of variables within the scope.
>>  
>> For the below example:
>>  
>> int global;
>> int func( int t)
>> { 
>>   //scope 1
>>   {
>>      int a;
>>      ....
>>   }
>>   return x;
>> }
>>  
>> For "scope 1", I should be able to collect that "a" is a local variable in scope1 and should also be able to identify whether "a" is static or non-static.
>>  
>> Regards,
>> Pankaj
>> _______________________________________________
>> 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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