gdb/ 2014-10-02 Jan Kratochvil Fix 100x slowdown regression on DWZ files. * dwarf2read.c (struct dwarf2_per_objfile): Add line_header_hash. (struct line_header): Add offset and offset_in_dwz. (dwarf_decode_lines): Add parameter decode_mapping to the declaration. (free_line_header_voidp): New declaration. (line_header_hash, line_header_eq): New functions. (dwarf2_build_include_psymtabs): Update dwarf_decode_lines caller. (handle_DW_AT_stmt_list): Use dwarf2_per_objfile->line_header_hash. (free_line_header_voidp): New function. (dwarf_decode_line_header): Initialize offset and offset_in_dwz. (dwarf_decode_lines): New parameter decode_mapping, use it. diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c index 9d0ee13..206dc10 100644 --- a/gdb/dwarf2read.c +++ b/gdb/dwarf2read.c @@ -309,6 +309,9 @@ struct dwarf2_per_objfile /* The CUs we recently read. */ VEC (dwarf2_per_cu_ptr) *just_read_cus; + + /* Table containing line_header indexed by offset and offset_in_dwz. */ + htab_t line_header_hash; }; static struct dwarf2_per_objfile *dwarf2_per_objfile; @@ -1025,6 +1028,12 @@ typedef void (die_reader_func_ftype) (const struct die_reader_specs *reader, which contains the following information. */ struct line_header { + /* Offset of line number information in .debug_line section. */ + sect_offset offset; + + /* OFFSET is for struct dwz_file associated with dwarf2_per_objfile. */ + unsigned offset_in_dwz : 1; + unsigned int total_length; unsigned short version; unsigned int header_length; @@ -1513,7 +1522,7 @@ static struct line_header *dwarf_decode_line_header (unsigned int offset, static void dwarf_decode_lines (struct line_header *, const char *, struct dwarf2_cu *, struct partial_symtab *, - CORE_ADDR); + CORE_ADDR, int decode_mapping); static void dwarf2_start_subfile (const char *, const char *, const char *); @@ -1845,6 +1854,8 @@ static void free_dwo_file_cleanup (void *); static void process_cu_includes (void); static void check_producer (struct dwarf2_cu *cu); + +static void free_line_header_voidp (void *arg); /* Various complaints about symbol reading that don't abort the process. */ @@ -1911,6 +1922,29 @@ dwarf2_invalid_attrib_class_complaint (const char *arg1, const char *arg2) _("invalid attribute class or form for '%s' in '%s'"), arg1, arg2); } + +/* Hash function for line_header_hash. */ + +static hashval_t +line_header_hash (const void *item) +{ + const struct line_header *ofs = item; + + return ofs->offset.sect_off ^ ofs->offset_in_dwz; +} + +/* Equality function for line_header_hash. */ + +static int +line_header_eq (const void *item_lhs, const void *item_rhs) +{ + const struct line_header *ofs_lhs = item_lhs; + const struct line_header *ofs_rhs = item_rhs; + + return (ofs_lhs->offset.sect_off == ofs_rhs->offset.sect_off + && ofs_lhs->offset_in_dwz == ofs_rhs->offset_in_dwz); +} + #if WORDS_BIGENDIAN @@ -4449,7 +4483,7 @@ dwarf2_build_include_psymtabs (struct dwarf2_cu *cu, return; /* No linetable, so no includes. */ /* NOTE: pst->dirname is DW_AT_comp_dir (if present). */ - dwarf_decode_lines (lh, pst->dirname, cu, pst, pst->textlow); + dwarf_decode_lines (lh, pst->dirname, cu, pst, pst->textlow, 1); free_line_header (lh); } @@ -8975,24 +9009,64 @@ static void handle_DW_AT_stmt_list (struct die_info *die, struct dwarf2_cu *cu, const char *comp_dir, CORE_ADDR lowpc) /* ARI: editCase function */ { + struct objfile *objfile = dwarf2_per_objfile->objfile; struct attribute *attr; + unsigned int line_offset; + struct line_header *line_header, line_header_local; + unsigned u; + void **slot; + int decode_mapping; gdb_assert (! cu->per_cu->is_debug_types); attr = dwarf2_attr (die, DW_AT_stmt_list, cu); - if (attr) + if (attr == NULL) + return; + + line_offset = DW_UNSND (attr); + + if (dwarf2_per_objfile->line_header_hash == NULL) { - unsigned int line_offset = DW_UNSND (attr); - struct line_header *line_header - = dwarf_decode_line_header (line_offset, cu); + dwarf2_per_objfile->line_header_hash + = htab_create_alloc_ex (127, line_header_hash, line_header_eq, + free_line_header_voidp, + &objfile->objfile_obstack, + hashtab_obstack_allocate, + dummy_obstack_deallocate); + } - if (line_header) - { - cu->line_header = line_header; - make_cleanup (free_cu_line_header, cu); - dwarf_decode_lines (line_header, comp_dir, cu, NULL, lowpc); - } + line_header_local.offset.sect_off = line_offset; + line_header_local.offset_in_dwz = cu->per_cu->is_dwz; + slot = htab_find_slot (dwarf2_per_objfile->line_header_hash, + &line_header_local, NO_INSERT); + + /* For DW_TAG_compile_unit we need info like symtab::linetable which + is not present in *SLOT. */ + if (die->tag == DW_TAG_partial_unit && slot != NULL) + { + gdb_assert (*slot != NULL); + cu->line_header = *slot; + return; + } + + line_header = dwarf_decode_line_header (line_offset, cu); + if (line_header == NULL) + return; + cu->line_header = line_header; + + slot = htab_find_slot (dwarf2_per_objfile->line_header_hash, + &line_header_local, INSERT); + gdb_assert (slot != NULL); + if (*slot == NULL) + *slot = line_header; + else + { + gdb_assert (die->tag != DW_TAG_partial_unit); + make_cleanup (free_cu_line_header, cu); } + decode_mapping = (die->tag != DW_TAG_partial_unit); + dwarf_decode_lines (line_header, comp_dir, cu, NULL, lowpc, + decode_mapping); } /* Process DW_TAG_compile_unit or DW_TAG_partial_unit. */ @@ -16863,6 +16937,16 @@ free_line_header (struct line_header *lh) xfree (lh); } +/* Stub for free_line_header to match void * callback types. */ + +static void +free_line_header_voidp (void *arg) +{ + struct line_header *lh = arg; + + free_line_header (lh); +} + /* Add an entry to LH's include directory table. */ static void @@ -16993,6 +17077,9 @@ dwarf_decode_line_header (unsigned int offset, struct dwarf2_cu *cu) back_to = make_cleanup ((make_cleanup_ftype *) free_line_header, (void *) lh); + lh->offset.sect_off = offset; + lh->offset_in_dwz = cu->per_cu->is_dwz; + line_ptr = section->buffer + offset; /* Read in the header. */ @@ -17605,18 +17692,23 @@ dwarf_decode_lines_1 (struct line_header *lh, const char *comp_dir, E.g. expand_line_sal requires this when finding psymtabs to expand. A good testcase for this is mb-inline.exp. - LOWPC is the lowest address in CU (or 0 if not known). */ + LOWPC is the lowest address in CU (or 0 if not known). + + Boolean DECODE_MAPPING specifies we need to fully decode .debug_line + for its PC<->lines mapping information. Otherwise only filenames + tables is read in. */ static void dwarf_decode_lines (struct line_header *lh, const char *comp_dir, struct dwarf2_cu *cu, struct partial_symtab *pst, - CORE_ADDR lowpc) + CORE_ADDR lowpc, int decode_mapping) { struct objfile *objfile = cu->objfile; const int decode_for_pst_p = (pst != NULL); struct subfile *first_subfile = current_subfile; - dwarf_decode_lines_1 (lh, comp_dir, cu, decode_for_pst_p, lowpc); + if (decode_mapping) + dwarf_decode_lines_1 (lh, comp_dir, cu, decode_for_pst_p, lowpc); if (decode_for_pst_p) {