Adrian Prantl
2015-Jan-19 18:29 UTC
[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 >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20150119/3f109cd0/attachment.html>
David Blaikie
2015-Jan-19 18:34 UTC
[LLVMdev] Dropping the DW_ prefix from names in dwarfdump
On Mon, Jan 19, 2015 at 10:29 AM, Adrian Prantl <aprantl at apple.com> wrote:> > 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> 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. >Well all I was suggesting was dropping the prefixes - this wouldn't result in any information loss, but possibly readability loss. apart from that, I think we could drop some verbosity too - just like we now print constants, file/directory names, without their form, etc, etc - we could probably do the same for strings (printing out the offset in the string table all the time is mostly excessive) and probably other types. That would actually be a loss of information that would certainly need a flag.> > -- 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" ) > 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 > > >-------------- next part -------------- An HTML attachment was scrubbed... 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Frédéric Riss
2015-Jan-19 18:42 UTC
[LLVMdev] Dropping the DW_ prefix from names in dwarfdump
> On Jan 19, 2015, at 10:34 AM, David Blaikie <dblaikie at gmail.com> wrote: > > > > On Mon, Jan 19, 2015 at 10:29 AM, Adrian Prantl <aprantl at apple.com <mailto:aprantl at apple.com>> wrote: > >> On Jan 19, 2015, at 10:26 AM, Adrian Prantl <aprantl at apple.com <mailto: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. > > Well all I was suggesting was dropping the prefixes - this wouldn't result in any information loss, but possibly readability loss.As I said in the review thread, I dropped the DW_ prefix for expressions as they can be multiple of them on the same line. I have no strong feeling one way or another for Attributes or Tags.> apart from that, I think we could drop some verbosity too - just like we now print constants, file/directory names, without their form, etc, etc - we could probably do the same for strings (printing out the offset in the string table all the time is mostly excessive) and probably other types. That would actually be a loss of information that would certainly need a flag.One of the next things I wanted to do was to drop the FORM display by default. This would actually save a lot more horizontal space than the DW_ prefixes and in my experience you nearly never need it. Of course there needs to be a flag to get it back, because ‘nearly never’ ain’t ‘never :-). Fred> > > -- 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 >> > >-------------- next part -------------- An HTML attachment was scrubbed... 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