| /* DWARF 2 debugging format support for GDB. |
| |
| Copyright (C) 1994-2018 Free Software Foundation, Inc. |
| |
| This file is part of GDB. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 3 of the License, or |
| (at your option) any later version. |
| |
| This program is distributed in the hope that it will be useful, |
| but WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| |
| #ifndef DWARF2READ_H |
| #define DWARF2READ_H |
| |
| #include <unordered_map> |
| #include "dwarf-index-cache.h" |
| #include "filename-seen-cache.h" |
| #include "gdb_obstack.h" |
| |
| /* Hold 'maintenance (set|show) dwarf' commands. */ |
| extern struct cmd_list_element *set_dwarf_cmdlist; |
| extern struct cmd_list_element *show_dwarf_cmdlist; |
| |
| typedef struct dwarf2_per_cu_data *dwarf2_per_cu_ptr; |
| DEF_VEC_P (dwarf2_per_cu_ptr); |
| |
| /* A descriptor for dwarf sections. |
| |
| S.ASECTION, SIZE are typically initialized when the objfile is first |
| scanned. BUFFER, READIN are filled in later when the section is read. |
| If the section contained compressed data then SIZE is updated to record |
| the uncompressed size of the section. |
| |
| DWP file format V2 introduces a wrinkle that is easiest to handle by |
| creating the concept of virtual sections contained within a real section. |
| In DWP V2 the sections of the input DWO files are concatenated together |
| into one section, but section offsets are kept relative to the original |
| input section. |
| If this is a virtual dwp-v2 section, S.CONTAINING_SECTION is a backlink to |
| the real section this "virtual" section is contained in, and BUFFER,SIZE |
| describe the virtual section. */ |
| |
| struct dwarf2_section_info |
| { |
| union |
| { |
| /* If this is a real section, the bfd section. */ |
| asection *section; |
| /* If this is a virtual section, pointer to the containing ("real") |
| section. */ |
| struct dwarf2_section_info *containing_section; |
| } s; |
| /* Pointer to section data, only valid if readin. */ |
| const gdb_byte *buffer; |
| /* The size of the section, real or virtual. */ |
| bfd_size_type size; |
| /* If this is a virtual section, the offset in the real section. |
| Only valid if is_virtual. */ |
| bfd_size_type virtual_offset; |
| /* True if we have tried to read this section. */ |
| char readin; |
| /* True if this is a virtual section, False otherwise. |
| This specifies which of s.section and s.containing_section to use. */ |
| char is_virtual; |
| }; |
| |
| typedef struct dwarf2_section_info dwarf2_section_info_def; |
| DEF_VEC_O (dwarf2_section_info_def); |
| |
| /* Read the contents of the section INFO. |
| OBJFILE is the main object file, but not necessarily the file where |
| the section comes from. E.g., for DWO files the bfd of INFO is the bfd |
| of the DWO file. |
| If the section is compressed, uncompress it before returning. */ |
| |
| void dwarf2_read_section (struct objfile *objfile, dwarf2_section_info *info); |
| |
| struct tu_stats |
| { |
| int nr_uniq_abbrev_tables; |
| int nr_symtabs; |
| int nr_symtab_sharers; |
| int nr_stmt_less_type_units; |
| int nr_all_type_units_reallocs; |
| }; |
| |
| struct dwarf2_debug_sections; |
| struct mapped_index; |
| struct mapped_debug_names; |
| struct signatured_type; |
| struct die_info; |
| typedef struct die_info *die_info_ptr; |
| |
| /* Collection of data recorded per objfile. |
| This hangs off of dwarf2_objfile_data_key. */ |
| |
| struct dwarf2_per_objfile : public allocate_on_obstack |
| { |
| /* Construct a dwarf2_per_objfile for OBJFILE. NAMES points to the |
| dwarf2 section names, or is NULL if the standard ELF names are |
| used. */ |
| dwarf2_per_objfile (struct objfile *objfile, |
| const dwarf2_debug_sections *names); |
| |
| ~dwarf2_per_objfile (); |
| |
| DISABLE_COPY_AND_ASSIGN (dwarf2_per_objfile); |
| |
| /* Return the CU/TU given its index. |
| |
| This is intended for loops like: |
| |
| for (i = 0; i < (dwarf2_per_objfile->n_comp_units |
| + dwarf2_per_objfile->n_type_units); ++i) |
| { |
| dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->get_cutu (i); |
| |
| ...; |
| } |
| */ |
| dwarf2_per_cu_data *get_cutu (int index); |
| |
| /* Return the CU given its index. |
| This differs from get_cutu in that it's for when you know INDEX refers to a |
| CU. */ |
| dwarf2_per_cu_data *get_cu (int index); |
| |
| /* Return the TU given its index. |
| This differs from get_cutu in that it's for when you know INDEX refers to a |
| TU. */ |
| signatured_type *get_tu (int index); |
| |
| /* Free all cached compilation units. */ |
| void free_cached_comp_units (); |
| private: |
| /* This function is mapped across the sections and remembers the |
| offset and size of each of the debugging sections we are |
| interested in. */ |
| void locate_sections (bfd *abfd, asection *sectp, |
| const dwarf2_debug_sections &names); |
| |
| public: |
| dwarf2_section_info info {}; |
| dwarf2_section_info abbrev {}; |
| dwarf2_section_info line {}; |
| dwarf2_section_info loc {}; |
| dwarf2_section_info loclists {}; |
| dwarf2_section_info macinfo {}; |
| dwarf2_section_info macro {}; |
| dwarf2_section_info str {}; |
| dwarf2_section_info line_str {}; |
| dwarf2_section_info ranges {}; |
| dwarf2_section_info rnglists {}; |
| dwarf2_section_info addr {}; |
| dwarf2_section_info frame {}; |
| dwarf2_section_info eh_frame {}; |
| dwarf2_section_info gdb_index {}; |
| dwarf2_section_info debug_names {}; |
| dwarf2_section_info debug_aranges {}; |
| |
| VEC (dwarf2_section_info_def) *types = NULL; |
| |
| /* Back link. */ |
| struct objfile *objfile = NULL; |
| |
| /* Table of all the compilation units. This is used to locate |
| the target compilation unit of a particular reference. */ |
| std::vector<dwarf2_per_cu_data *> all_comp_units; |
| |
| /* The .debug_types-related CUs (TUs). */ |
| std::vector<signatured_type *> all_type_units; |
| |
| /* Table of struct type_unit_group objects. |
| The hash key is the DW_AT_stmt_list value. */ |
| htab_t type_unit_groups {}; |
| |
| /* A table mapping .debug_types signatures to its signatured_type entry. |
| This is NULL if the .debug_types section hasn't been read in yet. */ |
| htab_t signatured_types {}; |
| |
| /* Type unit statistics, to see how well the scaling improvements |
| are doing. */ |
| struct tu_stats tu_stats {}; |
| |
| /* A chain of compilation units that are currently read in, so that |
| they can be freed later. */ |
| dwarf2_per_cu_data *read_in_chain = NULL; |
| |
| /* A table mapping DW_AT_dwo_name values to struct dwo_file objects. |
| This is NULL if the table hasn't been allocated yet. */ |
| htab_t dwo_files {}; |
| |
| /* True if we've checked for whether there is a DWP file. */ |
| bool dwp_checked = false; |
| |
| /* The DWP file if there is one, or NULL. */ |
| std::unique_ptr<struct dwp_file> dwp_file; |
| |
| /* The shared '.dwz' file, if one exists. This is used when the |
| original data was compressed using 'dwz -m'. */ |
| std::unique_ptr<struct dwz_file> dwz_file; |
| |
| /* A flag indicating whether this objfile has a section loaded at a |
| VMA of 0. */ |
| bool has_section_at_zero = false; |
| |
| /* True if we are using the mapped index, |
| or we are faking it for OBJF_READNOW's sake. */ |
| bool using_index = false; |
| |
| /* The mapped index, or NULL if .gdb_index is missing or not being used. */ |
| std::unique_ptr<mapped_index> index_table; |
| |
| /* The mapped index, or NULL if .debug_names is missing or not being used. */ |
| std::unique_ptr<mapped_debug_names> debug_names_table; |
| |
| /* When using index_table, this keeps track of all quick_file_names entries. |
| TUs typically share line table entries with a CU, so we maintain a |
| separate table of all line table entries to support the sharing. |
| Note that while there can be way more TUs than CUs, we've already |
| sorted all the TUs into "type unit groups", grouped by their |
| DW_AT_stmt_list value. Therefore the only sharing done here is with a |
| CU and its associated TU group if there is one. */ |
| htab_t quick_file_names_table {}; |
| |
| /* Set during partial symbol reading, to prevent queueing of full |
| symbols. */ |
| bool reading_partial_symbols = false; |
| |
| /* Table mapping type DIEs to their struct type *. |
| This is NULL if not allocated yet. |
| The mapping is done via (CU/TU + DIE offset) -> type. */ |
| htab_t die_type_hash {}; |
| |
| /* The CUs we recently read. */ |
| std::vector<dwarf2_per_cu_data *> just_read_cus; |
| |
| /* Table containing line_header indexed by offset and offset_in_dwz. */ |
| htab_t line_header_hash {}; |
| |
| /* Table containing all filenames. This is an optional because the |
| table is lazily constructed on first access. */ |
| gdb::optional<filename_seen_cache> filenames_cache; |
| |
| /* If we loaded the index from an external file, this contains the |
| resources associated to the open file, memory mapping, etc. */ |
| std::unique_ptr<index_cache_resource> index_cache_res; |
| |
| /* Mapping from abstract origin DIE to concrete DIEs that reference it as |
| DW_AT_abstract_origin. */ |
| std::unordered_map<die_info_ptr, std::vector<die_info_ptr>> |
| abstract_to_concrete; |
| }; |
| |
| /* Get the dwarf2_per_objfile associated to OBJFILE. */ |
| |
| dwarf2_per_objfile *get_dwarf2_per_objfile (struct objfile *objfile); |
| |
| /* Persistent data held for a compilation unit, even when not |
| processing it. We put a pointer to this structure in the |
| read_symtab_private field of the psymtab. */ |
| |
| struct dwarf2_per_cu_data |
| { |
| /* The start offset and length of this compilation unit. |
| NOTE: Unlike comp_unit_head.length, this length includes |
| initial_length_size. |
| If the DIE refers to a DWO file, this is always of the original die, |
| not the DWO file. */ |
| sect_offset sect_off; |
| unsigned int length; |
| |
| /* DWARF standard version this data has been read from (such as 4 or 5). */ |
| short dwarf_version; |
| |
| /* Flag indicating this compilation unit will be read in before |
| any of the current compilation units are processed. */ |
| unsigned int queued : 1; |
| |
| /* This flag will be set when reading partial DIEs if we need to load |
| absolutely all DIEs for this compilation unit, instead of just the ones |
| we think are interesting. It gets set if we look for a DIE in the |
| hash table and don't find it. */ |
| unsigned int load_all_dies : 1; |
| |
| /* Non-zero if this CU is from .debug_types. |
| Struct dwarf2_per_cu_data is contained in struct signatured_type iff |
| this is non-zero. */ |
| unsigned int is_debug_types : 1; |
| |
| /* Non-zero if this CU is from the .dwz file. */ |
| unsigned int is_dwz : 1; |
| |
| /* Non-zero if reading a TU directly from a DWO file, bypassing the stub. |
| This flag is only valid if is_debug_types is true. |
| We can't read a CU directly from a DWO file: There are required |
| attributes in the stub. */ |
| unsigned int reading_dwo_directly : 1; |
| |
| /* Non-zero if the TU has been read. |
| This is used to assist the "Stay in DWO Optimization" for Fission: |
| When reading a DWO, it's faster to read TUs from the DWO instead of |
| fetching them from random other DWOs (due to comdat folding). |
| If the TU has already been read, the optimization is unnecessary |
| (and unwise - we don't want to change where gdb thinks the TU lives |
| "midflight"). |
| This flag is only valid if is_debug_types is true. */ |
| unsigned int tu_read : 1; |
| |
| /* The section this CU/TU lives in. |
| If the DIE refers to a DWO file, this is always the original die, |
| not the DWO file. */ |
| struct dwarf2_section_info *section; |
| |
| /* Set to non-NULL iff this CU is currently loaded. When it gets freed out |
| of the CU cache it gets reset to NULL again. This is left as NULL for |
| dummy CUs (a CU header, but nothing else). */ |
| struct dwarf2_cu *cu; |
| |
| /* The corresponding dwarf2_per_objfile. */ |
| struct dwarf2_per_objfile *dwarf2_per_objfile; |
| |
| /* When dwarf2_per_objfile->using_index is true, the 'quick' field |
| is active. Otherwise, the 'psymtab' field is active. */ |
| union |
| { |
| /* The partial symbol table associated with this compilation unit, |
| or NULL for unread partial units. */ |
| struct partial_symtab *psymtab; |
| |
| /* Data needed by the "quick" functions. */ |
| struct dwarf2_per_cu_quick_data *quick; |
| } v; |
| |
| /* The CUs we import using DW_TAG_imported_unit. This is filled in |
| while reading psymtabs, used to compute the psymtab dependencies, |
| and then cleared. Then it is filled in again while reading full |
| symbols, and only deleted when the objfile is destroyed. |
| |
| This is also used to work around a difference between the way gold |
| generates .gdb_index version <=7 and the way gdb does. Arguably this |
| is a gold bug. For symbols coming from TUs, gold records in the index |
| the CU that includes the TU instead of the TU itself. This breaks |
| dw2_lookup_symbol: It assumes that if the index says symbol X lives |
| in CU/TU Y, then one need only expand Y and a subsequent lookup in Y |
| will find X. Alas TUs live in their own symtab, so after expanding CU Y |
| we need to look in TU Z to find X. Fortunately, this is akin to |
| DW_TAG_imported_unit, so we just use the same mechanism: For |
| .gdb_index version <=7 this also records the TUs that the CU referred |
| to. Concurrently with this change gdb was modified to emit version 8 |
| indices so we only pay a price for gold generated indices. |
| http://sourceware.org/bugzilla/show_bug.cgi?id=15021. */ |
| VEC (dwarf2_per_cu_ptr) *imported_symtabs; |
| }; |
| |
| /* Entry in the signatured_types hash table. */ |
| |
| struct signatured_type |
| { |
| /* The "per_cu" object of this type. |
| This struct is used iff per_cu.is_debug_types. |
| N.B.: This is the first member so that it's easy to convert pointers |
| between them. */ |
| struct dwarf2_per_cu_data per_cu; |
| |
| /* The type's signature. */ |
| ULONGEST signature; |
| |
| /* Offset in the TU of the type's DIE, as read from the TU header. |
| If this TU is a DWO stub and the definition lives in a DWO file |
| (specified by DW_AT_GNU_dwo_name), this value is unusable. */ |
| cu_offset type_offset_in_tu; |
| |
| /* Offset in the section of the type's DIE. |
| If the definition lives in a DWO file, this is the offset in the |
| .debug_types.dwo section. |
| The value is zero until the actual value is known. |
| Zero is otherwise not a valid section offset. */ |
| sect_offset type_offset_in_section; |
| |
| /* Type units are grouped by their DW_AT_stmt_list entry so that they |
| can share them. This points to the containing symtab. */ |
| struct type_unit_group *type_unit_group; |
| |
| /* The type. |
| The first time we encounter this type we fully read it in and install it |
| in the symbol tables. Subsequent times we only need the type. */ |
| struct type *type; |
| |
| /* Containing DWO unit. |
| This field is valid iff per_cu.reading_dwo_directly. */ |
| struct dwo_unit *dwo_unit; |
| }; |
| |
| typedef struct signatured_type *sig_type_ptr; |
| DEF_VEC_P (sig_type_ptr); |
| |
| #endif /* DWARF2READ_H */ |