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David Blaikie

2015-Jan-19 18:08 UTC

[LLVMdev] Dropping the DW_ prefix from names in dwarfdump

Hey guys,

Frederic is introducing the expression dumping support and in the interests
of tersity is skipping the "DW_" in every "DW_OP" (heck, we
could even skip
the "OP" given the context - nothing else textual can appear there,
right?)

Any thoughts on skipping the "DW_" (maybe even the AT/TAG/FORM too) in
the
rest of dwarfdump? (skipping the AT/TAG (FORM would be relatively easy I
think) would be a bit trickier, but still identifiable/solvable) I haven't
tried it to see how it looks/reads.
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Adrian Prantl

2015-Jan-19 18:26 UTC

head link

[LLVMdev] Dropping the DW_ prefix from names in dwarfdump

> On Jan 19, 2015, at 10:08 AM, David Blaikie <dblaikie at gmail.com>
wrote:
> 
> Hey guys,
> 
> Frederic is introducing the expression dumping support and in the interests
of tersity is skipping the "DW_" in every "DW_OP" (heck, we
could even skip the "OP" given the context - nothing else textual can
appear there, right?)
> 
> Any thoughts on skipping the "DW_" (maybe even the AT/TAG/FORM
too) in the rest of dwarfdump? (skipping the AT/TAG (FORM would be relatively
easy I think) would be a bit trickier, but still identifiable/solvable) I
haven't tried it to see how it looks/reads.
I think we should have a switchable level of verbosity. I think that the Darwin
dwarfdump utility could serve as an example (at least to fuel the discussion):
Here is Darwin's dwarfdump output with the default settings

----------------------------------------------------------------------
 File: out.o (x86_64)
----------------------------------------------------------------------
.debug_info contents:

0x00000000: Compile Unit: length = 0x0000005b  version = 0x0004  abbr_offset =
0x00000000  addr_size = 0x08  (next CU at 0x0000005f)

0x0000000b: TAG_compile_unit [1] *
             AT_producer( "clang version 3.5.0 (209308)" )
             AT_language( DW_LANG_C_plus_plus )
             AT_name( "test.cc" )
             AT_stmt_list( 0x00000000 )
             AT_comp_dir( "/llvm_cmake" )
             AT_low_pc( 0x0000000000000000 )
             AT_high_pc( 0x00000184 )

0x0000002a:     TAG_subprogram [2] *
                 AT_low_pc( 0x0000000000000000 )
                 AT_high_pc( 0x00000184 )
                 AT_frame_base( rbp )
                 AT_MIPS_linkage_name( "_Z3bari" )
                 AT_name( "bar" )
                 AT_decl_file( "/llvm_cmake/test.cc" )
                 AT_decl_line( 1 )
                 AT_type( {0x00000057} ( int ) )
                 AT_external( true )

0x00000047:         TAG_formal_parameter [3]  
                     AT_location( 0x00000000
                        0x0000000000000000 - 0x00000000000000b9: rdi+0
                        0x00000000000000b9 - 0x0000000000000184: rsp+16, deref )
                     AT_name( "y" )
                     AT_decl_file( "/llvm_cmake/test.cc" )
                     AT_decl_line( 1 )
                     AT_type( {0x00000057} ( int ) )

0x00000056:         NULL

0x00000057:     TAG_base_type [4]  
                 AT_name( "int" )
                 AT_encoding( DW_ATE_signed )
                 AT_byte_size( 0x04 )

0x0000005e:     NULL


and here is the same file with -v:

----------------------------------------------------------------------
 File: out.o {mach64-x86_64-MH_OBJECT} (x86_64)
----------------------------------------------------------------------
.debug_info contents:

0x00000000: Compile Unit: length = 0x0000005b  version = 0x0004  abbr_offset =
0x00000000  addr_size = 0x08  (next CU at 0x0000005f)

0x0000000b: TAG_compile_unit [1] *
0x0000000c:  AT_producer( .debug_str[0x00000000] = "clang version 3.5.0
(209308)" )
0x00000010:  AT_language( 0x0004 ( DW_LANG_C_plus_plus ) )
0x00000012:  AT_name( .debug_str[0x0000001d] = "test.cc" )
0x00000016:  AT_stmt_list( 0x00000000 ( 0x00000000 ) )
0x0000001a:  AT_comp_dir( .debug_str[0x00000025] = "/llvm_cmake" )
0x0000001e:  AT_low_pc( 0x0000000000000000 )
0x00000026:  AT_high_pc( 0x00000184 )

0x0000002a:     TAG_subprogram [2] *
0x0000002b:      AT_low_pc( 0x0000000000000000 )
0x00000033:      AT_high_pc( 0x00000184 )
0x00000037:      AT_frame_base( <0x0000000000000001> 56  ( reg6 ) )
0x00000039:      AT_MIPS_linkage_name( .debug_str[0x00000039] =
"_Z3bari" )
0x0000003d:      AT_name( .debug_str[0x00000035] = "bar" )
0x00000041:      AT_decl_file( 0x01 ( "/llvm_cmake/test.cc" ) )
0x00000042:      AT_decl_line( 0x01 ( 1 ) )
0x00000043:      AT_type( cu + 0x00000057 => {0x00000057} ( int ) )
0x00000047:      AT_external( true )

0x00000047:         TAG_formal_parameter [3]  
0x00000048:          AT_location( 0x00000000
                        0x0000000000000000 - 0x00000000000000b9: breg5 +0
                        0x00000000000000b9 - 0x0000000000000184: breg7 +16,
deref )
0x0000004c:          AT_name( .debug_str[0x00000045] = "y" )
0x00000050:          AT_decl_file( 0x01 ( "/llvm_cmake/test.cc" ) )
0x00000051:          AT_decl_line( 0x01 ( 1 ) )
0x00000052:          AT_type( cu + 0x00000057 => {0x00000057} ( int ) )

0x00000056:         NULL

0x00000057:     TAG_base_type [4]  
0x00000058:      AT_name( .debug_str[0x00000041] = "int" )
0x0000005c:      AT_encoding( 0x05 ( DW_ATE_signed ) )
0x0000005d:      AT_byte_size( 0x04 )

0x0000005e:     NULL

I particularly like the inline location expressions.

-- adrian

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Adrian Prantl

2015-Jan-19 18:29 UTC

head link

[LLVMdev] Dropping the DW_ prefix from names in dwarfdump

> On Jan 19, 2015, at 10:26 AM, Adrian Prantl <aprantl at apple.com>
wrote:
> 
> 
>> On Jan 19, 2015, at 10:08 AM, David Blaikie <dblaikie at gmail.com
<mailto:dblaikie at gmail.com>> wrote:
>> 
>> Hey guys,
>> 
>> Frederic is introducing the expression dumping support and in the
interests of tersity is skipping the "DW_" in every "DW_OP"
(heck, we could even skip the "OP" given the context - nothing else
textual can appear there, right?)
I think it always depends on what you are debugging. When I’m interested whether
the encoding is correct, I think I’d prefer to have all these details in there,
even if they are redundant. When I’m debugging, e.g., the source location
associated with a function argument, I wouldn’t care about which Form is used to
encode the information.

-- adrian
>> 
>> Any thoughts on skipping the "DW_" (maybe even the
AT/TAG/FORM too) in the rest of dwarfdump? (skipping the AT/TAG (FORM would be
relatively easy I think) would be a bit trickier, but still
identifiable/solvable) I haven't tried it to see how it looks/reads.
> 
> I think we should have a switchable level of verbosity. I think that the
Darwin dwarfdump utility could serve as an example (at least to fuel the
discussion):
> Here is Darwin's dwarfdump output with the default settings
> 
> ----------------------------------------------------------------------
>  File: out.o (x86_64)
> ----------------------------------------------------------------------
> .debug_info contents:
> 
> 0x00000000: Compile Unit: length = 0x0000005b  version = 0x0004 
abbr_offset = 0x00000000  addr_size = 0x08  (next CU at 0x0000005f)
> 
> 0x0000000b: TAG_compile_unit [1] *
>              AT_producer( "clang version 3.5.0 (209308)" )
>              AT_language( DW_LANG_C_plus_plus )
>              AT_name( "test.cc <http://test.cc/>" )
>              AT_stmt_list( 0x00000000 )
>              AT_comp_dir( "/llvm_cmake" )
>              AT_low_pc( 0x0000000000000000 )
>              AT_high_pc( 0x00000184 )
> 
> 0x0000002a:     TAG_subprogram [2] *
>                  AT_low_pc( 0x0000000000000000 )
>                  AT_high_pc( 0x00000184 )
>                  AT_frame_base( rbp )
>                  AT_MIPS_linkage_name( "_Z3bari" )
>                  AT_name( "bar" )
>                  AT_decl_file( "/llvm_cmake/test.cc
<http://test.cc/>" )
>                  AT_decl_line( 1 )
>                  AT_type( {0x00000057} ( int ) )
>                  AT_external( true )
> 
> 0x00000047:         TAG_formal_parameter [3]  
>                      AT_location( 0x00000000
>                         0x0000000000000000 - 0x00000000000000b9: rdi+0
>                         0x00000000000000b9 - 0x0000000000000184: rsp+16,
deref )
>                      AT_name( "y" )
>                      AT_decl_file( "/llvm_cmake/test.cc
<http://test.cc/>" )
>                      AT_decl_line( 1 )
>                      AT_type( {0x00000057} ( int ) )
> 
> 0x00000056:         NULL
> 
> 0x00000057:     TAG_base_type [4]  
>                  AT_name( "int" )
>                  AT_encoding( DW_ATE_signed )
>                  AT_byte_size( 0x04 )
> 
> 0x0000005e:     NULL
> 
> 
> and here is the same file with -v:
> 
> ----------------------------------------------------------------------
>  File: out.o {mach64-x86_64-MH_OBJECT} (x86_64)
> ----------------------------------------------------------------------
> .debug_info contents:
> 
> 0x00000000: Compile Unit: length = 0x0000005b  version = 0x0004 
abbr_offset = 0x00000000  addr_size = 0x08  (next CU at 0x0000005f)
> 
> 0x0000000b: TAG_compile_unit [1] *
> 0x0000000c:  AT_producer( .debug_str[0x00000000] = "clang version
3.5.0 (209308)" )
> 0x00000010:  AT_language( 0x0004 ( DW_LANG_C_plus_plus ) )
> 0x00000012:  AT_name( .debug_str[0x0000001d] = "test.cc
<http://test.cc/>" )
> 0x00000016:  AT_stmt_list( 0x00000000 ( 0x00000000 ) )
> 0x0000001a:  AT_comp_dir( .debug_str[0x00000025] = "/llvm_cmake"
)
> 0x0000001e:  AT_low_pc( 0x0000000000000000 )
> 0x00000026:  AT_high_pc( 0x00000184 )
> 
> 0x0000002a:     TAG_subprogram [2] *
> 0x0000002b:      AT_low_pc( 0x0000000000000000 )
> 0x00000033:      AT_high_pc( 0x00000184 )
> 0x00000037:      AT_frame_base( <0x0000000000000001> 56  ( reg6 ) )
> 0x00000039:      AT_MIPS_linkage_name( .debug_str[0x00000039] =
"_Z3bari" )
> 0x0000003d:      AT_name( .debug_str[0x00000035] = "bar" )
> 0x00000041:      AT_decl_file( 0x01 ( "/llvm_cmake/test.cc
<http://test.cc/>" ) )
> 0x00000042:      AT_decl_line( 0x01 ( 1 ) )
> 0x00000043:      AT_type( cu + 0x00000057 => {0x00000057} ( int ) )
> 0x00000047:      AT_external( true )
> 
> 0x00000047:         TAG_formal_parameter [3]  
> 0x00000048:          AT_location( 0x00000000
>                         0x0000000000000000 - 0x00000000000000b9: breg5 +0
>                         0x00000000000000b9 - 0x0000000000000184: breg7 +16,
deref )
> 0x0000004c:          AT_name( .debug_str[0x00000045] = "y" )
> 0x00000050:          AT_decl_file( 0x01 ( "/llvm_cmake/test.cc
<http://test.cc/>" ) )
> 0x00000051:          AT_decl_line( 0x01 ( 1 ) )
> 0x00000052:          AT_type( cu + 0x00000057 => {0x00000057} ( int ) )
> 
> 0x00000056:         NULL
> 
> 0x00000057:     TAG_base_type [4]  
> 0x00000058:      AT_name( .debug_str[0x00000041] = "int" )
> 0x0000005c:      AT_encoding( 0x05 ( DW_ATE_signed ) )
> 0x0000005d:      AT_byte_size( 0x04 )
> 
> 0x0000005e:     NULL
> 
> I particularly like the inline location expressions.
> 
> -- adrian
> 
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