On Tue, 7 Jan 2025, Jakub Jelinek wrote:
> Hi!
>
> DWARF has voted in yesterday https://dwarfstd.org/issues/241209.1.html ,
> which is basically just a guarantee that the DWARF 6 draft
> DW_AT_language_{name,version} attribute codes and content of
> https://dwarfstd.org/languages-v6.html can be used as an extension
> in DWARF 5 and won't be changed.
>
> So, this patch is an alternative to the
> https://gcc.gnu.org/pipermail/gcc-patches/2024-November/669671.html
> patch, which had the major problem that it required changing all the
> DWARF consumers to be able to debug C17 or later or C++17 or later
> sources.
> This patch uses still DWARF 5 DW_LANG_C11 or DW_LANG_C_plus_plus_14,
> the latest code in DWARF 5 proper, so all DWARF 5 capable consumers
> should be able to deal with that, but additionally emits the
> DWARF 6 attributes so that newer DWARF consumers can see it isn't
> just C++14 but say C++23 or C11 but C23. Consumers which don't know
> those DWARF 6 attributes would just ignore them. This is like any other
> -gno-strict-dwarf extension, except that normally we emit say DWARF 5
> codes where possible only after DWARF 5 is released, while in this case
> there is a guarantee it can be used before DWARF 6 is released.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
Ok with me.
Thanks,
Richard.
> 2025-01-07 Jakub Jelinek <ja...@redhat.com>
>
> include/
> * dwarf2.h (enum dwarf_source_language): Fix comment pasto.
> (enum dwarf_source_language_name): New type.
> * dwarf2.def (DW_AT_language_name, DW_AT_language_version): New
> DWARF 6 codes.
> gcc/
> * dwarf2out.cc (break_out_comdat_types): Copy over
> DW_AT_language_{name,version} if present.
> (output_skeleton_debug_sections): Remove also
> DW_AT_language_{name,version}.
> (gen_compile_unit_die): For C17, C23, C2Y, C++17, C++20, C++23
> and C++26 emit for -gdwarf-5 -gno-strict-dwarf also
> DW_AT_language_{name,version} attributes.
> gcc/testsuite/
> * g++.dg/debug/dwarf2/lang-cpp17.C: Add -gno-strict-dwarf to
> dg-options. Check also for DW_AT_language_{name,version} values.
> * g++.dg/debug/dwarf2/lang-cpp20.C: Likewise.
> * g++.dg/debug/dwarf2/lang-cpp23.C: New test.
>
> --- include/dwarf2.h.jj 2025-01-02 11:47:47.431981968 +0100
> +++ include/dwarf2.h 2025-01-06 18:55:59.802378204 +0100
> @@ -411,7 +411,7 @@ enum dwarf_source_language
> DW_LANG_Hylo = 0x0042,
>
> DW_LANG_lo_user = 0x8000, /* Implementation-defined range start.
> */
> - DW_LANG_hi_user = 0xffff, /* Implementation-defined range start.
> */
> + DW_LANG_hi_user = 0xffff, /* Implementation-defined range end. */
>
> /* MIPS. */
> DW_LANG_Mips_Assembler = 0x8001,
> @@ -428,6 +428,59 @@ enum dwarf_source_language
> DW_LANG_Rust_old = 0x9000
> };
>
> +/* DWARF 6 source language names and codes. */
> +enum dwarf_source_language_name
> + {
> + /* https://dwarfstd.org/languages-v6.html */
> + DW_LNAME_Ada = 0x0001,
> + DW_LNAME_BLISS = 0x0002,
> + DW_LNAME_C = 0x0003,
> + DW_LNAME_C_plus_plus = 0x0004,
> + DW_LNAME_Cobol = 0x0005,
> + DW_LNAME_Crystal = 0x0006,
> + DW_LNAME_D = 0x0007,
> + DW_LNAME_Dylan = 0x0008,
> + DW_LNAME_Fortran = 0x0009,
> + DW_LNAME_Go = 0x000a,
> + DW_LNAME_Haskell = 0x000b,
> + DW_LNAME_Java = 0x000c,
> + DW_LNAME_Julia = 0x000d,
> + DW_LNAME_Kotlin = 0x000e,
> + DW_LNAME_Modula2 = 0x000f,
> + DW_LNAME_Modula3 = 0x0010,
> + DW_LNAME_ObjC = 0x0011,
> + DW_LNAME_ObjC_plus_plus = 0x0012,
> + DW_LNAME_OCaml = 0x0013,
> + DW_LNAME_OpenCL_C = 0x0014,
> + DW_LNAME_Pascal = 0x0015,
> + DW_LNAME_PLI = 0x0016,
> + DW_LNAME_Python = 0x0017,
> + DW_LNAME_RenderScript = 0x0018,
> + DW_LNAME_Rust = 0x0019,
> + DW_LNAME_Swift = 0x001a,
> + DW_LNAME_UPC = 0x001b,
> + DW_LNAME_Zig = 0x001c,
> + DW_LNAME_Assembly = 0x001d,
> + DW_LNAME_C_sharp = 0x001e,
> + DW_LNAME_Mojo = 0x001f,
> + DW_LNAME_GLSL = 0x0020,
> + DW_LNAME_GLSL_ES = 0x0021,
> + DW_LNAME_HLSL = 0x0022,
> + DW_LNAME_OpenCL_CPP = 0x0023,
> + DW_LNAME_CPP_for_OpenCL = 0x0024,
> + DW_LNAME_SYCL = 0x0025,
> + DW_LNAME_Ruby = 0x0026,
> + DW_LNAME_Move = 0x0027,
> + DW_LNAME_Hylo = 0x0028,
> + DW_LNAME_HIP = 0x0029,
> + DW_LNAME_Odin = 0x002a,
> + DW_LNAME_P4 = 0x002b,
> + DW_LNAME_Metal = 0x002c,
> +
> + DW_LNAME_lo_user = 0x8000, /* Implementation-defined range start.
> */
> + DW_LNAME_hi_user = 0xffff /* Implementation-defined range end. */
> + };
> +
> /* Names and codes for macro information. */
> enum dwarf_macinfo_record_type
> {
> --- include/dwarf2.def.jj 2025-01-02 11:47:47.191985318 +0100
> +++ include/dwarf2.def 2025-01-06 18:39:02.642383150 +0100
> @@ -364,6 +364,9 @@ DW_AT (DW_AT_export_symbols, 0x89)
> DW_AT (DW_AT_deleted, 0x8a)
> DW_AT (DW_AT_defaulted, 0x8b)
> DW_AT (DW_AT_loclists_base, 0x8c)
> +/* DWARF 6. */
> +DW_AT (DW_AT_language_name, 0x90)
> +DW_AT (DW_AT_language_version, 0x91)
>
> DW_AT_DUP (DW_AT_lo_user, 0x2000) /* Implementation-defined range start. */
> DW_AT_DUP (DW_AT_hi_user, 0x3fff) /* Implementation-defined range end. */
> --- gcc/dwarf2out.cc.jj 2025-01-02 11:23:35.541251268 +0100
> +++ gcc/dwarf2out.cc 2025-01-07 10:09:16.866866563 +0100
> @@ -8755,6 +8755,14 @@ break_out_comdat_types (dw_die_ref die)
> unit = new_die (DW_TAG_type_unit, NULL, NULL);
> add_AT_unsigned (unit, DW_AT_language,
> get_AT_unsigned (comp_unit_die (), DW_AT_language));
> + if (unsigned lname = get_AT_unsigned (comp_unit_die (),
> + DW_AT_language_name))
> + {
> + add_AT_unsigned (unit, DW_AT_language_name, lname);
> + add_AT_unsigned (unit, DW_AT_language_version,
> + get_AT_unsigned (comp_unit_die (),
> + DW_AT_language_version));
> + }
>
> /* Add the new unit's type DIE into the comdat type list. */
> type_node = ggc_cleared_alloc<comdat_type_node> ();
> @@ -11404,6 +11412,8 @@ output_skeleton_debug_sections (dw_die_r
> /* These attributes will be found in the full debug_info section. */
> remove_AT (comp_unit, DW_AT_producer);
> remove_AT (comp_unit, DW_AT_language);
> + remove_AT (comp_unit, DW_AT_language_name);
> + remove_AT (comp_unit, DW_AT_language_version);
>
> switch_to_section (debug_skeleton_info_section);
> ASM_OUTPUT_LABEL (asm_out_file, debug_skeleton_info_section_label);
> @@ -25318,7 +25328,7 @@ gen_compile_unit_die (const char *filena
> {
> dw_die_ref die;
> const char *language_string = lang_hooks.name;
> - int language;
> + int language, lname, lversion;
>
> die = new_die (DW_TAG_compile_unit, NULL, NULL);
>
> @@ -25366,6 +25376,8 @@ gen_compile_unit_die (const char *filena
> }
>
> language = DW_LANG_C;
> + lname = 0;
> + lversion = 0;
> if (startswith (language_string, "GNU C")
> && ISDIGIT (language_string[5]))
> {
> @@ -25376,11 +25388,28 @@ gen_compile_unit_die (const char *filena
> language = DW_LANG_C99;
>
> if (dwarf_version >= 5 /* || !dwarf_strict */)
> - if (strcmp (language_string, "GNU C11") == 0
> - || strcmp (language_string, "GNU C17") == 0
> - || strcmp (language_string, "GNU C23") == 0
> - || strcmp (language_string, "GNU C2Y") == 0)
> - language = DW_LANG_C11;
> + {
> + if (strcmp (language_string, "GNU C11") == 0)
> + language = DW_LANG_C11;
> + else if (strcmp (language_string, "GNU C17") == 0)
> + {
> + language = DW_LANG_C11;
> + lname = DW_LNAME_C;
> + lversion = 201710;
> + }
> + else if (strcmp (language_string, "GNU C23") == 0)
> + {
> + language = DW_LANG_C11;
> + lname = DW_LNAME_C;
> + lversion = 202311;
> + }
> + else if (strcmp (language_string, "GNU C2Y") == 0)
> + {
> + language = DW_LANG_C11;
> + lname = DW_LNAME_C;
> + lversion = 202500;
> + }
> + }
> }
> }
> else if (startswith (language_string, "GNU C++"))
> @@ -25392,12 +25421,30 @@ gen_compile_unit_die (const char *filena
> language = DW_LANG_C_plus_plus_11;
> else if (strcmp (language_string, "GNU C++14") == 0)
> language = DW_LANG_C_plus_plus_14;
> - else if (strcmp (language_string, "GNU C++17") == 0
> - || strcmp (language_string, "GNU C++20") == 0
> - || strcmp (language_string, "GNU C++23") == 0
> - || strcmp (language_string, "GNU C++26") == 0)
> - /* For now. */
> - language = DW_LANG_C_plus_plus_14;
> + else if (strcmp (language_string, "GNU C++17") == 0)
> + {
> + language = DW_LANG_C_plus_plus_14;
> + lname = DW_LNAME_C_plus_plus;
> + lversion = 201703;
> + }
> + else if (strcmp (language_string, "GNU C++20") == 0)
> + {
> + language = DW_LANG_C_plus_plus_14;
> + lname = DW_LNAME_C_plus_plus;
> + lversion = 202002;
> + }
> + else if (strcmp (language_string, "GNU C++23") == 0)
> + {
> + language = DW_LANG_C_plus_plus_14;
> + lname = DW_LNAME_C_plus_plus;
> + lversion = 202302;
> + }
> + else if (strcmp (language_string, "GNU C++26") == 0)
> + {
> + language = DW_LANG_C_plus_plus_14;
> + lname = DW_LNAME_C_plus_plus;
> + lversion = 202400;
> + }
> }
> }
> else if (strcmp (language_string, "GNU F77") == 0)
> @@ -25441,6 +25488,11 @@ gen_compile_unit_die (const char *filena
> language = DW_LANG_Ada83;
>
> add_AT_unsigned (die, DW_AT_language, language);
> + if (lname && dwarf_version >= 5 && !dwarf_strict)
> + {
> + add_AT_unsigned (die, DW_AT_language_name, lname);
> + add_AT_unsigned (die, DW_AT_language_version, lversion);
> + }
>
> switch (language)
> {
> --- gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp17.C.jj 2021-01-18
> 07:18:14.929659650 +0100
> +++ gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp17.C 2025-01-07
> 10:07:46.473125326 +0100
> @@ -1,8 +1,10 @@
> // { dg-do compile }
> -// { dg-options "-O -std=c++17 -gdwarf-5 -dA" }
> +// { dg-options "-O -std=c++17 -gdwarf-5 -dA -gno-strict-dwarf" }
> // { dg-skip-if "AIX DWARF5" { powerpc-ibm-aix* } }
> -// For -gdwarf-6 hopefully DW_LANG_C_plus_plus_17
> // DW_LANG_C_plus_plus_14 = 0x0021
> +// DW_LNAME_C_plus_plus = 0x0004 201703
> // { dg-final { scan-assembler "0x21\[^\n\r]* DW_AT_language" } } */
> +// { dg-final { scan-assembler "0x4\[^\n\r]* DW_AT_language_name" } } */
> +// { dg-final { scan-assembler "0x313e7\[^\n\r]* DW_AT_language_version" } }
> */
>
> int version;
> --- gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp20.C.jj 2021-01-18
> 14:52:42.946040137 +0100
> +++ gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp20.C 2025-01-07
> 10:08:28.982533366 +0100
> @@ -1,8 +1,10 @@
> // { dg-do compile }
> -// { dg-options "-O -std=c++20 -gdwarf-5 -dA" }
> +// { dg-options "-O -std=c++20 -gdwarf-5 -dA -gno-strict-dwarf" }
> // { dg-skip-if "AIX DWARF5" { powerpc-ibm-aix* } }
> -// For -gdwarf-6 hopefully DW_LANG_C_plus_plus_20
> // DW_LANG_C_plus_plus_14 = 0x0021
> +// DW_LNAME_C_plus_plus = 0x0004 202002
> // { dg-final { scan-assembler "0x21\[^\n\r]* DW_AT_language" } } */
> +// { dg-final { scan-assembler "0x4\[^\n\r]* DW_AT_language_name" } } */
> +// { dg-final { scan-assembler "0x31512\[^\n\r]* DW_AT_language_version" } }
> */
>
> int version;
> --- gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp23.C.jj 2025-01-07
> 10:07:54.926007612 +0100
> +++ gcc/testsuite/g++.dg/debug/dwarf2/lang-cpp23.C 2025-01-07
> 10:08:19.206669497 +0100
> @@ -0,0 +1,10 @@
> +// { dg-do compile }
> +// { dg-options "-O -std=c++23 -gdwarf-5 -dA -gno-strict-dwarf" }
> +// { dg-skip-if "AIX DWARF5" { powerpc-ibm-aix* } }
> +// DW_LANG_C_plus_plus_14 = 0x0021
> +// DW_LNAME_C_plus_plus = 0x0004 202302
> +// { dg-final { scan-assembler "0x21\[^\n\r]* DW_AT_language" } } */
> +// { dg-final { scan-assembler "0x4\[^\n\r]* DW_AT_language_name" } } */
> +// { dg-final { scan-assembler "0x3163e\[^\n\r]* DW_AT_language_version" } }
> */
> +
> +int version;
>
> Jakub
>
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
