Em Thu, Sep 29, 2022 at 09:42:53AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Wed, Sep 28, 2022 at 08:25:51AM -0700, Nathan Chancellor escreveu: > > On Wed, Sep 28, 2022 at 10:42:53AM -0300, Arnaldo Carvalho de Melo wrote: > > > Can you please provide the vmlinux file where this takes place? > > Sure thing, it is compressed to save some bandwidth while downloading: > > https://1drv.ms/u/s!AsQNYeB-IEbqnnzsULjM1pXmOlI5?e=qHKjuW > So, fixed the case reported, DW_TAG_label outside a DW_TAG_lexblock, on > asm DW_TAG_compile_unit DWARF containers, ... Forgot the patch: >From f01e5f3a849558b8ed6b310686d10738f4c2f3bf Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Date: Thu, 29 Sep 2022 09:43:16 -0300 Subject: [PATCH 1/1] dwarf_loader: Support DW_TAG_label outside DW_TAG_lexblock This happens with asm CUs, noticed when building the Linux kernel with clang 15, where we have, for instance: Contents of the .debug_info section: Compilation Unit @ offset 0x0: Length: 0x1df (32-bit) Version: 5 Unit Type: DW_UT_compile (1) Abbrev Offset: 0x0 Pointer Size: 8 <0><c>: Abbrev Number: 1 (DW_TAG_compile_unit) <d> DW_AT_stmt_list : 0x0 <11> DW_AT_ranges : 0xc <15> DW_AT_name : arch/x86/kernel/verify_cpu.S <32> DW_AT_comp_dir : /home/nathan/cbl/src/linux <4d> DW_AT_producer : ClangBuiltLinux clang version 16.0.0 (https://github.com/llvm/llvm-project 7e22179d38c438fedb0d9bb0cff1585843bd7082) <c2> DW_AT_language : 32769 (MIPS assembler) <1><c4>: Abbrev Number: 2 (DW_TAG_label) <c5> DW_AT_name : startup_64 <d0> DW_AT_decl_file : 0x0 <d4> DW_AT_decl_line : 0x364 <d8> DW_AT_low_pc : 0xffffffff81000000 <1><e0>: Abbrev Number: 2 (DW_TAG_label) <e1> DW_AT_name : secondary_startup_64 <f6> DW_AT_decl_file : 0x0 <fa> DW_AT_decl_line : 0x399 <fe> DW_AT_low_pc : 0xffffffff81000060 <1><106>: Abbrev Number: 2 (DW_TAG_label) <107> DW_AT_name : secondary_startup_64_no_verify <126> DW_AT_decl_file : 0x0 <12a> DW_AT_decl_line : 0x39f <12e> DW_AT_low_pc : 0xffffffff81000065 <1><136>: Abbrev Number: 2 (DW_TAG_label) <137> DW_AT_name : verify_cpu <142> DW_AT_decl_file : 0x0 <146> DW_AT_decl_line : 0x430 <14a> DW_AT_low_pc : 0xffffffff81000150 <SNIP> Reported-by: Nathan Chancellor <nathan@xxxxxxxxxx> Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Yonghong Song <yhs@xxxxxx> Link: https://lore.kernel.org/dwarves/YzWSzXKcm6rSWOC5@xxxxxxxxxx Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> --- dwarf_loader.c | 16 ++++++++++++++-- 1 file changed, 14 insertions(+), 2 deletions(-) diff --git a/dwarf_loader.c b/dwarf_loader.c index 631bbd434eb2a4e6..28a912ec725a6e68 100644 --- a/dwarf_loader.c +++ b/dwarf_loader.c @@ -1485,7 +1485,12 @@ static struct tag *die__create_new_label(Dwarf_Die *die, if (label == NULL) return NULL; - lexblock__add_label(lexblock, label); + if (lexblock != NULL) { + // asm CUs have labels and they will be in the cu top level tag list + // See die__process_unit() + lexblock__add_label(lexblock, label); + } + return &label->ip.tag; } @@ -2037,6 +2042,12 @@ static struct tag *__die__process_tag(Dwarf_Die *die, struct cu *cu, */ tag = &unsupported_tag; break; + case DW_TAG_label: + if (conf->ignore_labels) + tag = &unsupported_tag; // callers will assume conf->ignore_labels is true + else // We can have labels in asm CUs, no lexblock + tag = die__create_new_label(die, NULL, cu, conf); + break; } if (tag != NULL) @@ -2055,7 +2066,8 @@ static int die__process_unit(Dwarf_Die *die, struct cu *cu, struct conf_load *co if (tag == &unsupported_tag) { // XXX special case DW_TAG_dwarf_procedure, appears when looking at a recent ~/bin/perf // Investigate later how to properly support this... - if (dwarf_tag(die) != DW_TAG_dwarf_procedure) + if (dwarf_tag(die) != DW_TAG_dwarf_procedure && + dwarf_tag(die) != DW_TAG_label) // conf->ignore_labels == true, see die__process_tag() tag__print_not_supported(dwarf_tag(die)); continue; } -- 2.37.3
