1 // gdb-index.cc -- generate .gdb_index section for fast debug lookup
3 // Copyright (C) 2012-2014 Free Software Foundation, Inc.
4 // Written by Cary Coutant <ccoutant@google.com>.
6 // This file is part of gold.
8 // This program is free software; you can redistribute it and/or modify
9 // it under the terms of the GNU General Public License as published by
10 // the Free Software Foundation; either version 3 of the License, or
11 // (at your option) any later version.
13 // This program is distributed in the hope that it will be useful,
14 // but WITHOUT ANY WARRANTY; without even the implied warranty of
15 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 // GNU General Public License for more details.
18 // You should have received a copy of the GNU General Public License
19 // along with this program; if not, write to the Free Software
20 // Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
21 // MA 02110-1301, USA.
25 #include "gdb-index.h"
26 #include "dwarf_reader.h"
35 const int gdb_index_version = 7;
37 // Sizes of various records in the .gdb_index section.
38 const int gdb_index_offset_size = 4;
39 const int gdb_index_hdr_size = 6 * gdb_index_offset_size;
40 const int gdb_index_cu_size = 16;
41 const int gdb_index_tu_size = 24;
42 const int gdb_index_addr_size = 16 + gdb_index_offset_size;
43 const int gdb_index_sym_size = 2 * gdb_index_offset_size;
45 // This class manages the hashed symbol table for the .gdb_index section.
46 // It is essentially equivalent to the hashtab implementation in libiberty,
47 // but is copied into gdb sources and here for compatibility because its
48 // data structure is exposed on disk.
55 : size_(0), capacity_(0), hashtab_(NULL)
60 for (size_t i = 0; i < this->capacity_; ++i)
61 if (this->hashtab_[i] != NULL)
62 delete this->hashtab_[i];
63 delete[] this->hashtab_;
70 // Resize the hash table if necessary.
71 if (4 * this->size_ / 3 >= this->capacity_)
74 T** slot = this->find_slot(symbol);
84 // Return the current size.
87 { return this->size_; }
89 // Return the current capacity.
92 { return this->capacity_; }
94 // Return the contents of slot N.
97 { return this->hashtab_[n]; }
100 // Find a symbol in the hash table, or return an empty slot if
101 // the symbol is not in the table.
105 unsigned int index = symbol->hash() & (this->capacity_ - 1);
106 unsigned int step = ((symbol->hash() * 17) & (this->capacity_ - 1)) | 1;
110 if (this->hashtab_[index] == NULL
111 || this->hashtab_[index]->equal(symbol))
112 return &this->hashtab_[index];
113 index = (index + step) & (this->capacity_ - 1);
117 // Expand the hash table.
121 if (this->capacity_ == 0)
123 // Allocate the hash table for the first time.
124 this->capacity_ = Gdb_hashtab::initial_size;
125 this->hashtab_ = new T*[this->capacity_];
126 memset(this->hashtab_, 0, this->capacity_ * sizeof(T*));
130 // Expand and rehash.
131 unsigned int old_cap = this->capacity_;
132 T** old_hashtab = this->hashtab_;
133 this->capacity_ *= 2;
134 this->hashtab_ = new T*[this->capacity_];
135 memset(this->hashtab_, 0, this->capacity_ * sizeof(T*));
136 for (size_t i = 0; i < old_cap; ++i)
138 if (old_hashtab[i] != NULL)
140 T** slot = this->find_slot(old_hashtab[i]);
141 *slot = old_hashtab[i];
144 delete[] old_hashtab;
148 // Initial size of the hash table; must be a power of 2.
149 static const int initial_size = 1024;
155 // The hash function for strings in the mapped index. This is copied
156 // directly from gdb/dwarf2read.c.
159 mapped_index_string_hash(const unsigned char* str)
164 while ((c = *str++) != 0)
166 if (gdb_index_version >= 5)
168 r = r * 67 + c - 113;
174 // A specialization of Dwarf_info_reader, for building the .gdb_index.
176 class Gdb_index_info_reader : public Dwarf_info_reader
179 Gdb_index_info_reader(bool is_type_unit,
181 const unsigned char* symbols,
184 unsigned int reloc_shndx,
185 unsigned int reloc_type,
186 Gdb_index* gdb_index)
187 : Dwarf_info_reader(is_type_unit, object, symbols, symbols_size, shndx,
188 reloc_shndx, reloc_type),
189 gdb_index_(gdb_index), cu_index_(0), cu_language_(0)
192 ~Gdb_index_info_reader()
193 { this->clear_declarations(); }
195 // Print usage statistics.
200 // Visit a compilation unit.
202 visit_compilation_unit(off_t cu_offset, off_t cu_length, Dwarf_die*);
204 // Visit a type unit.
206 visit_type_unit(off_t tu_offset, off_t tu_length, off_t type_offset,
207 uint64_t signature, Dwarf_die*);
210 // A map for recording DIEs we've seen that may be referred to be
211 // later DIEs (via DW_AT_specification or DW_AT_abstract_origin).
212 // The map is indexed by a DIE offset within the compile unit.
213 // PARENT_OFFSET_ is the offset of the DIE that represents the
214 // outer context, and NAME_ is a pointer to a component of the
215 // fully-qualified name.
216 // Normally, the names we point to are in a string table, so we don't
217 // have to manage them, but when we have a fully-qualified name
218 // computed, we put it in the table, and set PARENT_OFFSET_ to -1
219 // indicate a string that we are managing.
220 struct Declaration_pair
222 Declaration_pair(off_t parent_offset, const char* name)
223 : parent_offset_(parent_offset), name_(name)
226 off_t parent_offset_;
229 typedef Unordered_map<off_t, Declaration_pair> Declaration_map;
231 // Visit a top-level DIE.
233 visit_top_die(Dwarf_die* die);
235 // Visit the children of a DIE.
237 visit_children(Dwarf_die* die, Dwarf_die* context);
241 visit_die(Dwarf_die* die, Dwarf_die* context);
243 // Visit the children of a DIE.
245 visit_children_for_decls(Dwarf_die* die);
249 visit_die_for_decls(Dwarf_die* die, Dwarf_die* context);
251 // Guess a fully-qualified name for a class type, based on member function
254 guess_full_class_name(Dwarf_die* die);
256 // Add a declaration DIE to the table of declarations.
258 add_declaration(Dwarf_die* die, Dwarf_die* context);
260 // Add a declaration whose fully-qualified name is already known.
262 add_declaration_with_full_name(Dwarf_die* die, const char* full_name);
264 // Return the context for a DIE whose parent is at DIE_OFFSET.
266 get_context(off_t die_offset);
268 // Construct a fully-qualified name for DIE.
270 get_qualified_name(Dwarf_die* die, Dwarf_die* context);
272 // Record the address ranges for a compilation unit.
274 record_cu_ranges(Dwarf_die* die);
276 // Wrapper for read_pubtable.
278 read_pubnames_and_pubtypes(Dwarf_die* die);
280 // Read the .debug_pubnames and .debug_pubtypes tables.
282 read_pubtable(Dwarf_pubnames_table* table, off_t offset);
284 // Clear the declarations map.
286 clear_declarations();
288 // The Gdb_index section.
289 Gdb_index* gdb_index_;
290 // The current CU index (negative for a TU).
292 // The language of the current CU or TU.
293 unsigned int cu_language_;
294 // Map from DIE offset to (parent offset, name) pair,
295 // for DW_AT_specification.
296 Declaration_map declarations_;
299 // Total number of DWARF compilation units processed.
300 static unsigned int dwarf_cu_count;
301 // Number of DWARF compilation units with pubnames/pubtypes.
302 static unsigned int dwarf_cu_nopubnames_count;
303 // Total number of DWARF type units processed.
304 static unsigned int dwarf_tu_count;
305 // Number of DWARF type units with pubnames/pubtypes.
306 static unsigned int dwarf_tu_nopubnames_count;
309 // Total number of DWARF compilation units processed.
310 unsigned int Gdb_index_info_reader::dwarf_cu_count = 0;
311 // Number of DWARF compilation units without pubnames/pubtypes.
312 unsigned int Gdb_index_info_reader::dwarf_cu_nopubnames_count = 0;
313 // Total number of DWARF type units processed.
314 unsigned int Gdb_index_info_reader::dwarf_tu_count = 0;
315 // Number of DWARF type units without pubnames/pubtypes.
316 unsigned int Gdb_index_info_reader::dwarf_tu_nopubnames_count = 0;
318 // Process a compilation unit and parse its child DIE.
321 Gdb_index_info_reader::visit_compilation_unit(off_t cu_offset, off_t cu_length,
324 ++Gdb_index_info_reader::dwarf_cu_count;
325 this->cu_index_ = this->gdb_index_->add_comp_unit(cu_offset, cu_length);
326 this->visit_top_die(root_die);
329 // Process a type unit and parse its child DIE.
332 Gdb_index_info_reader::visit_type_unit(off_t tu_offset, off_t,
333 off_t type_offset, uint64_t signature,
336 ++Gdb_index_info_reader::dwarf_tu_count;
337 // Use a negative index to flag this as a TU instead of a CU.
338 this->cu_index_ = -1 - this->gdb_index_->add_type_unit(tu_offset, type_offset,
340 this->visit_top_die(root_die);
343 // Process a top-level DIE.
344 // For compile_unit DIEs, record the address ranges. For all
345 // interesting tags, add qualified names to the symbol table
346 // and process interesting children. We may need to process
347 // certain children just for saving declarations that might be
348 // referenced by later DIEs with a DW_AT_specification attribute.
351 Gdb_index_info_reader::visit_top_die(Dwarf_die* die)
353 this->clear_declarations();
357 case elfcpp::DW_TAG_compile_unit:
358 case elfcpp::DW_TAG_type_unit:
359 this->cu_language_ = die->int_attribute(elfcpp::DW_AT_language);
360 if (die->tag() == elfcpp::DW_TAG_compile_unit)
361 this->record_cu_ranges(die);
362 // If there is a pubnames and/or pubtypes section for this
363 // compilation unit, use those; otherwise, parse the DWARF
364 // info to extract the names.
365 if (!this->read_pubnames_and_pubtypes(die))
367 // Check for languages that require specialized knowledge to
368 // construct fully-qualified names, that we don't yet support.
369 if (this->cu_language_ == elfcpp::DW_LANG_Ada83
370 || this->cu_language_ == elfcpp::DW_LANG_Fortran77
371 || this->cu_language_ == elfcpp::DW_LANG_Fortran90
372 || this->cu_language_ == elfcpp::DW_LANG_Java
373 || this->cu_language_ == elfcpp::DW_LANG_Ada95
374 || this->cu_language_ == elfcpp::DW_LANG_Fortran95)
376 gold_warning(_("%s: --gdb-index currently supports "
377 "only C and C++ languages"),
378 this->object()->name().c_str());
381 if (die->tag() == elfcpp::DW_TAG_compile_unit)
382 ++Gdb_index_info_reader::dwarf_cu_nopubnames_count;
384 ++Gdb_index_info_reader::dwarf_tu_nopubnames_count;
385 this->visit_children(die, NULL);
389 // The top level DIE should be one of the above.
390 gold_warning(_("%s: top level DIE is not DW_TAG_compile_unit "
391 "or DW_TAG_type_unit"),
392 this->object()->name().c_str());
397 // Visit the children of PARENT, looking for symbols to add to the index.
398 // CONTEXT points to the DIE to use for constructing the qualified name --
399 // NULL if PARENT is the top-level DIE; otherwise it is the same as PARENT.
402 Gdb_index_info_reader::visit_children(Dwarf_die* parent, Dwarf_die* context)
404 off_t next_offset = 0;
405 for (off_t die_offset = parent->child_offset();
407 die_offset = next_offset)
409 Dwarf_die die(this, die_offset, parent);
412 this->visit_die(&die, context);
413 next_offset = die.sibling_offset();
417 // Visit a child DIE, looking for symbols to add to the index.
418 // CONTEXT is the parent DIE, used for constructing the qualified name;
419 // it is NULL if the parent DIE is the top-level DIE.
422 Gdb_index_info_reader::visit_die(Dwarf_die* die, Dwarf_die* context)
426 case elfcpp::DW_TAG_subprogram:
427 case elfcpp::DW_TAG_constant:
428 case elfcpp::DW_TAG_variable:
429 case elfcpp::DW_TAG_enumerator:
430 case elfcpp::DW_TAG_base_type:
431 if (die->is_declaration())
432 this->add_declaration(die, context);
435 // If the DIE is not a declaration, add it to the index.
436 std::string full_name = this->get_qualified_name(die, context);
437 if (!full_name.empty())
438 this->gdb_index_->add_symbol(this->cu_index_,
439 full_name.c_str(), 0);
442 case elfcpp::DW_TAG_typedef:
443 case elfcpp::DW_TAG_union_type:
444 case elfcpp::DW_TAG_class_type:
445 case elfcpp::DW_TAG_interface_type:
446 case elfcpp::DW_TAG_structure_type:
447 case elfcpp::DW_TAG_enumeration_type:
448 case elfcpp::DW_TAG_subrange_type:
449 case elfcpp::DW_TAG_namespace:
451 std::string full_name;
453 // For classes at the top level, we need to look for a
454 // member function with a linkage name in order to get
455 // the properly-canonicalized name.
457 && (die->tag() == elfcpp::DW_TAG_class_type
458 || die->tag() == elfcpp::DW_TAG_structure_type
459 || die->tag() == elfcpp::DW_TAG_union_type))
460 full_name.assign(this->guess_full_class_name(die));
462 // Because we will visit the children, we need to add this DIE
463 // to the declarations table.
464 if (full_name.empty())
465 this->add_declaration(die, context);
467 this->add_declaration_with_full_name(die, full_name.c_str());
469 // If the DIE is not a declaration, add it to the index.
470 // Gdb stores a namespace in the index even when it is
472 if (die->tag() == elfcpp::DW_TAG_namespace
473 || !die->is_declaration())
475 if (full_name.empty())
476 full_name = this->get_qualified_name(die, context);
477 if (!full_name.empty())
478 this->gdb_index_->add_symbol(this->cu_index_,
479 full_name.c_str(), 0);
482 // We're interested in the children only for namespaces and
483 // enumeration types. For enumeration types, we do not include
484 // the enumeration tag as part of the full name. For other tags,
485 // visit the children only to collect declarations.
486 if (die->tag() == elfcpp::DW_TAG_namespace
487 || die->tag() == elfcpp::DW_TAG_enumeration_type)
488 this->visit_children(die, die);
490 this->visit_children_for_decls(die);
498 // Visit the children of PARENT, looking only for declarations that
499 // may be referenced by later specification DIEs.
502 Gdb_index_info_reader::visit_children_for_decls(Dwarf_die* parent)
504 off_t next_offset = 0;
505 for (off_t die_offset = parent->child_offset();
507 die_offset = next_offset)
509 Dwarf_die die(this, die_offset, parent);
512 this->visit_die_for_decls(&die, parent);
513 next_offset = die.sibling_offset();
517 // Visit a child DIE, looking only for declarations that
518 // may be referenced by later specification DIEs.
521 Gdb_index_info_reader::visit_die_for_decls(Dwarf_die* die, Dwarf_die* context)
525 case elfcpp::DW_TAG_subprogram:
526 case elfcpp::DW_TAG_constant:
527 case elfcpp::DW_TAG_variable:
528 case elfcpp::DW_TAG_enumerator:
529 case elfcpp::DW_TAG_base_type:
531 if (die->is_declaration())
532 this->add_declaration(die, context);
535 case elfcpp::DW_TAG_typedef:
536 case elfcpp::DW_TAG_union_type:
537 case elfcpp::DW_TAG_class_type:
538 case elfcpp::DW_TAG_interface_type:
539 case elfcpp::DW_TAG_structure_type:
540 case elfcpp::DW_TAG_enumeration_type:
541 case elfcpp::DW_TAG_subrange_type:
542 case elfcpp::DW_TAG_namespace:
544 if (die->is_declaration())
545 this->add_declaration(die, context);
546 this->visit_children_for_decls(die);
554 // Extract the class name from the linkage name of a member function.
555 // This code is adapted from ../gdb/cp-support.c.
557 #define d_left(dc) (dc)->u.s_binary.left
558 #define d_right(dc) (dc)->u.s_binary.right
561 class_name_from_linkage_name(const char* linkage_name)
564 struct demangle_component* tree =
565 cplus_demangle_v3_components(linkage_name, DMGL_NO_OPTS, &storage);
571 // First strip off any qualifiers, if we have a function or
576 case DEMANGLE_COMPONENT_CONST:
577 case DEMANGLE_COMPONENT_RESTRICT:
578 case DEMANGLE_COMPONENT_VOLATILE:
579 case DEMANGLE_COMPONENT_CONST_THIS:
580 case DEMANGLE_COMPONENT_RESTRICT_THIS:
581 case DEMANGLE_COMPONENT_VOLATILE_THIS:
582 case DEMANGLE_COMPONENT_VENDOR_TYPE_QUAL:
590 // If what we have now is a function, discard the argument list.
591 if (tree->type == DEMANGLE_COMPONENT_TYPED_NAME)
594 // If what we have now is a template, strip off the template
595 // arguments. The left subtree may be a qualified name.
596 if (tree->type == DEMANGLE_COMPONENT_TEMPLATE)
599 // What we have now should be a name, possibly qualified.
600 // Additional qualifiers could live in the left subtree or the right
601 // subtree. Find the last piece.
603 struct demangle_component* prev_comp = NULL;
604 struct demangle_component* cur_comp = tree;
606 switch (cur_comp->type)
608 case DEMANGLE_COMPONENT_QUAL_NAME:
609 case DEMANGLE_COMPONENT_LOCAL_NAME:
610 prev_comp = cur_comp;
611 cur_comp = d_right(cur_comp);
613 case DEMANGLE_COMPONENT_TEMPLATE:
614 case DEMANGLE_COMPONENT_NAME:
615 case DEMANGLE_COMPONENT_CTOR:
616 case DEMANGLE_COMPONENT_DTOR:
617 case DEMANGLE_COMPONENT_OPERATOR:
618 case DEMANGLE_COMPONENT_EXTENDED_OPERATOR:
628 if (cur_comp != NULL && prev_comp != NULL)
630 // We want to discard the rightmost child of PREV_COMP.
631 *prev_comp = *d_left(prev_comp);
632 size_t allocated_size;
633 ret = cplus_demangle_print(DMGL_NO_OPTS, tree, 30, &allocated_size);
640 // Guess a fully-qualified name for a class type, based on member function
641 // linkage names. This is needed for class/struct/union types at the
642 // top level, because GCC does not always properly embed them within
643 // the namespace. As in gdb, we look for a member function with a linkage
644 // name and extract the qualified name from the demangled name.
647 Gdb_index_info_reader::guess_full_class_name(Dwarf_die* die)
649 std::string full_name;
650 off_t next_offset = 0;
652 // This routine scans ahead in the DIE structure, possibly advancing
653 // the relocation tracker beyond the current DIE. We need to checkpoint
654 // the tracker and reset it when we're done.
655 uint64_t checkpoint = this->get_reloc_checkpoint();
657 for (off_t child_offset = die->child_offset();
659 child_offset = next_offset)
661 Dwarf_die child(this, child_offset, die);
662 if (child.tag() == 0)
664 if (child.tag() == elfcpp::DW_TAG_subprogram)
666 const char* linkage_name = child.linkage_name();
667 if (linkage_name != NULL)
669 char* guess = class_name_from_linkage_name(linkage_name);
672 full_name.assign(guess);
678 next_offset = child.sibling_offset();
681 this->reset_relocs(checkpoint);
685 // Add a declaration DIE to the table of declarations.
688 Gdb_index_info_reader::add_declaration(Dwarf_die* die, Dwarf_die* context)
690 const char* name = die->name();
692 off_t parent_offset = context != NULL ? context->offset() : 0;
694 // If this DIE has a DW_AT_specification or DW_AT_abstract_origin
695 // attribute, use the parent and name from the earlier declaration.
696 off_t spec = die->specification();
698 spec = die->abstract_origin();
701 Declaration_map::iterator it = this->declarations_.find(spec);
702 if (it != this->declarations_.end())
704 parent_offset = it->second.parent_offset_;
705 name = it->second.name_;
711 if (die->tag() == elfcpp::DW_TAG_namespace)
712 name = "(anonymous namespace)";
713 else if (die->tag() == elfcpp::DW_TAG_union_type)
714 name = "(anonymous union)";
719 Declaration_pair decl(parent_offset, name);
720 this->declarations_.insert(std::make_pair(die->offset(), decl));
723 // Add a declaration whose fully-qualified name is already known.
724 // In the case where we had to get the canonical name by demangling
725 // a linkage name, this ensures we use that name instead of the one
726 // provided in DW_AT_name.
729 Gdb_index_info_reader::add_declaration_with_full_name(
731 const char* full_name)
733 // We need to copy the name.
734 int len = strlen(full_name);
735 char* copy = new char[len + 1];
736 memcpy(copy, full_name, len + 1);
738 // Flag that we now manage the memory this points to.
739 Declaration_pair decl(-1, copy);
740 this->declarations_.insert(std::make_pair(die->offset(), decl));
743 // Return the context for a DIE whose parent is at DIE_OFFSET.
746 Gdb_index_info_reader::get_context(off_t die_offset)
749 Declaration_map::iterator it = this->declarations_.find(die_offset);
750 if (it != this->declarations_.end())
752 off_t parent_offset = it->second.parent_offset_;
753 if (parent_offset > 0)
755 context = get_context(parent_offset);
756 context.append("::");
758 if (it->second.name_ != NULL)
759 context.append(it->second.name_);
764 // Construct the fully-qualified name for DIE.
767 Gdb_index_info_reader::get_qualified_name(Dwarf_die* die, Dwarf_die* context)
769 std::string full_name;
770 const char* name = die->name();
772 off_t parent_offset = context != NULL ? context->offset() : 0;
774 // If this DIE has a DW_AT_specification or DW_AT_abstract_origin
775 // attribute, use the parent and name from the earlier declaration.
776 off_t spec = die->specification();
778 spec = die->abstract_origin();
781 Declaration_map::iterator it = this->declarations_.find(spec);
782 if (it != this->declarations_.end())
784 parent_offset = it->second.parent_offset_;
785 name = it->second.name_;
789 if (name == NULL && die->tag() == elfcpp::DW_TAG_namespace)
790 name = "(anonymous namespace)";
791 else if (name == NULL)
794 // If this is an enumerator constant, skip the immediate parent,
795 // which is the enumeration tag.
796 if (die->tag() == elfcpp::DW_TAG_enumerator)
798 Declaration_map::iterator it = this->declarations_.find(parent_offset);
799 if (it != this->declarations_.end())
800 parent_offset = it->second.parent_offset_;
803 if (parent_offset > 0)
805 full_name.assign(this->get_context(parent_offset));
806 full_name.append("::");
808 full_name.append(name);
813 // Record the address ranges for a compilation unit.
816 Gdb_index_info_reader::record_cu_ranges(Dwarf_die* die)
821 off_t ranges_offset = die->ref_attribute(elfcpp::DW_AT_ranges, &shndx);
822 if (ranges_offset != -1)
824 Dwarf_range_list* ranges = this->read_range_list(shndx, ranges_offset);
826 this->gdb_index_->add_address_range_list(this->object(),
827 this->cu_index_, ranges);
831 off_t low_pc = die->address_attribute(elfcpp::DW_AT_low_pc, &shndx);
832 off_t high_pc = die->address_attribute(elfcpp::DW_AT_high_pc, &shndx2);
835 high_pc = die->uint_attribute(elfcpp::DW_AT_high_pc);
839 if ((low_pc != 0 || high_pc != 0) && low_pc != -1)
843 gold_warning(_("%s: DWARF info may be corrupt; low_pc and high_pc "
844 "are in different sections"),
845 this->object()->name().c_str());
848 if (shndx == 0 || this->object()->is_section_included(shndx))
850 Dwarf_range_list* ranges = new Dwarf_range_list();
851 ranges->add(shndx, low_pc, high_pc);
852 this->gdb_index_->add_address_range_list(this->object(),
853 this->cu_index_, ranges);
858 // Read table and add the relevant names to the index. Returns true
859 // if any names were added.
862 Gdb_index_info_reader::read_pubtable(Dwarf_pubnames_table* table, off_t offset)
864 // If we couldn't read the section when building the cu_pubname_map,
865 // then we won't find any pubnames now.
869 if (!table->read_header(offset))
874 const char* name = table->next_name(&flag_byte);
878 this->gdb_index_->add_symbol(this->cu_index_, name, flag_byte);
883 // Read the .debug_pubnames and .debug_pubtypes tables for the CU or TU.
884 // Returns TRUE if either a pubnames or pubtypes section was found.
887 Gdb_index_info_reader::read_pubnames_and_pubtypes(Dwarf_die* die)
889 // If this is a skeleton debug-type die (generated via
890 // -gsplit-dwarf), then the associated pubnames should have been
891 // read along with the corresponding CU. In any case, there isn't
892 // enough info inside to build a gdb index entry.
893 if (die->tag() == elfcpp::DW_TAG_type_unit
894 && die->string_attribute(elfcpp::DW_AT_GNU_dwo_name))
897 // We use stmt_list_off as a unique identifier for the
898 // compilation unit and its associated type units.
900 off_t stmt_list_off = die->ref_attribute (elfcpp::DW_AT_stmt_list,
902 // Look for the attr as either a flag or a ref.
903 off_t offset = die->ref_attribute(elfcpp::DW_AT_GNU_pubnames, &shndx);
905 // Newer versions of GCC generate CUs, but not TUs, with
906 // DW_AT_FORM_flag_present.
907 unsigned int flag = die->uint_attribute(elfcpp::DW_AT_GNU_pubnames);
908 if (offset == -1 && flag == 0)
910 // Didn't find the attribute.
911 if (die->tag() == elfcpp::DW_TAG_type_unit)
913 // If die is a TU, then it might correspond to a CU which we
914 // have read. If it does, then no need to read the pubnames.
915 // If it doesn't, then the caller will have to parse the
916 // dies manually to find the names.
917 return this->gdb_index_->pubnames_read(this->object(),
922 // No attribute on the CU means that no pubnames were read.
927 // We found the attribute, so we can check if the corresponding
928 // pubnames have been read.
929 if (this->gdb_index_->pubnames_read(this->object(), stmt_list_off))
932 this->gdb_index_->set_pubnames_read(this->object(), stmt_list_off);
934 // We have an attribute, and the pubnames haven't been read, so read
937 // In some of the cases, we could rely on the previous value of
938 // offset here, but sorting out which cases complicates the logic
939 // enough that it isn't worth it. So just look up the offset again.
940 offset = this->gdb_index_->find_pubname_offset(this->cu_offset());
941 names = this->read_pubtable(this->gdb_index_->pubnames_table(), offset);
944 offset = this->gdb_index_->find_pubtype_offset(this->cu_offset());
945 types = this->read_pubtable(this->gdb_index_->pubtypes_table(), offset);
946 return names || types;
949 // Clear the declarations map.
951 Gdb_index_info_reader::clear_declarations()
953 // Free strings in memory we manage.
954 for (Declaration_map::iterator it = this->declarations_.begin();
955 it != this->declarations_.end();
958 if (it->second.parent_offset_ == -1)
959 delete[] it->second.name_;
962 this->declarations_.clear();
965 // Print usage statistics.
967 Gdb_index_info_reader::print_stats()
969 fprintf(stderr, _("%s: DWARF CUs: %u\n"),
970 program_name, Gdb_index_info_reader::dwarf_cu_count);
971 fprintf(stderr, _("%s: DWARF CUs without pubnames/pubtypes: %u\n"),
972 program_name, Gdb_index_info_reader::dwarf_cu_nopubnames_count);
973 fprintf(stderr, _("%s: DWARF TUs: %u\n"),
974 program_name, Gdb_index_info_reader::dwarf_tu_count);
975 fprintf(stderr, _("%s: DWARF TUs without pubnames/pubtypes: %u\n"),
976 program_name, Gdb_index_info_reader::dwarf_tu_nopubnames_count);
981 // Construct the .gdb_index section.
983 Gdb_index::Gdb_index(Output_section* gdb_index_section)
984 : Output_section_data(4),
985 pubnames_table_(NULL),
986 pubtypes_table_(NULL),
987 gdb_index_section_(gdb_index_section),
992 cu_vector_offsets_(NULL),
998 stringpool_offset_(0),
999 pubnames_object_(NULL),
1000 stmt_list_offset_(-1)
1002 this->gdb_symtab_ = new Gdb_hashtab<Gdb_symbol>();
1005 Gdb_index::~Gdb_index()
1007 // Free the memory used by the symbol table.
1008 delete this->gdb_symtab_;
1009 // Free the memory used by the CU vectors.
1010 for (unsigned int i = 0; i < this->cu_vector_list_.size(); ++i)
1011 delete this->cu_vector_list_[i];
1015 // Scan the pubnames and pubtypes sections and build a map of the
1016 // various cus and tus they refer to, so we can process the entries
1017 // when we encounter the die for that cu or tu.
1018 // Return the just-read table so it can be cached.
1020 Dwarf_pubnames_table*
1021 Gdb_index::map_pubtable_to_dies(unsigned int attr,
1022 Gdb_index_info_reader* dwinfo,
1024 const unsigned char* symbols,
1027 uint64_t section_offset = 0;
1028 Dwarf_pubnames_table* table;
1029 Pubname_offset_map* map;
1031 if (attr == elfcpp::DW_AT_GNU_pubnames)
1033 table = new Dwarf_pubnames_table(dwinfo, false);
1034 map = &this->cu_pubname_map_;
1038 table = new Dwarf_pubnames_table(dwinfo, true);
1039 map = &this->cu_pubtype_map_;
1043 if (!table->read_section(object, symbols, symbols_size))
1046 while (table->read_header(section_offset))
1048 map->insert(std::make_pair(table->cu_offset(), section_offset));
1049 section_offset += table->subsection_size();
1055 // Wrapper for map_pubtable_to_dies
1058 Gdb_index::map_pubnames_and_types_to_dies(Gdb_index_info_reader* dwinfo,
1060 const unsigned char* symbols,
1063 // This is a new object, so reset the relevant variables.
1064 this->pubnames_object_ = object;
1065 this->stmt_list_offset_ = -1;
1067 delete this->pubnames_table_;
1068 this->pubnames_table_
1069 = this->map_pubtable_to_dies(elfcpp::DW_AT_GNU_pubnames, dwinfo,
1070 object, symbols, symbols_size);
1071 delete this->pubtypes_table_;
1072 this->pubtypes_table_
1073 = this->map_pubtable_to_dies(elfcpp::DW_AT_GNU_pubtypes, dwinfo,
1074 object, symbols, symbols_size);
1077 // Given a cu_offset, find the associated section of the pubnames
1081 Gdb_index::find_pubname_offset(off_t cu_offset)
1083 Pubname_offset_map::iterator it = this->cu_pubname_map_.find(cu_offset);
1084 if (it != this->cu_pubname_map_.end())
1089 // Given a cu_offset, find the associated section of the pubnames
1093 Gdb_index::find_pubtype_offset(off_t cu_offset)
1095 Pubname_offset_map::iterator it = this->cu_pubtype_map_.find(cu_offset);
1096 if (it != this->cu_pubtype_map_.end())
1101 // Scan a .debug_info or .debug_types input section.
1104 Gdb_index::scan_debug_info(bool is_type_unit,
1106 const unsigned char* symbols,
1109 unsigned int reloc_shndx,
1110 unsigned int reloc_type)
1112 Gdb_index_info_reader dwinfo(is_type_unit, object,
1113 symbols, symbols_size,
1116 if (object != this->pubnames_object_)
1117 map_pubnames_and_types_to_dies(&dwinfo, object, symbols, symbols_size);
1124 Gdb_index::add_symbol(int cu_index, const char* sym_name, uint8_t flags)
1126 unsigned int hash = mapped_index_string_hash(
1127 reinterpret_cast<const unsigned char*>(sym_name));
1128 Gdb_symbol* sym = new Gdb_symbol();
1129 this->stringpool_.add(sym_name, true, &sym->name_key);
1130 sym->hashval = hash;
1131 sym->cu_vector_index = 0;
1133 Gdb_symbol* found = this->gdb_symtab_->add(sym);
1136 // New symbol -- allocate a new CU index vector.
1137 found->cu_vector_index = this->cu_vector_list_.size();
1138 this->cu_vector_list_.push_back(new Cu_vector());
1142 // Found an existing symbol -- append to the existing
1147 // Add the CU index to the vector list for this symbol,
1148 // if it's not already on the list. We only need to
1149 // check the last added entry.
1150 Cu_vector* cu_vec = this->cu_vector_list_[found->cu_vector_index];
1151 if (cu_vec->size() == 0
1152 || cu_vec->back().first != cu_index
1153 || cu_vec->back().second != flags)
1154 cu_vec->push_back(std::make_pair(cu_index, flags));
1157 // Return TRUE if we have already processed the pubnames associated
1158 // with the statement list at the given OFFSET.
1161 Gdb_index::pubnames_read(const Relobj* object, off_t offset)
1163 bool ret = (this->pubnames_object_ == object
1164 && this->stmt_list_offset_ == offset);
1168 // Record that we have processed the pubnames associated with the
1169 // statement list for OBJECT at the given OFFSET.
1172 Gdb_index::set_pubnames_read(const Relobj* object, off_t offset)
1174 this->pubnames_object_ = object;
1175 this->stmt_list_offset_ = offset;
1178 // Set the size of the .gdb_index section.
1181 Gdb_index::set_final_data_size()
1183 // Finalize the string pool.
1184 this->stringpool_.set_string_offsets();
1186 // Compute the total size of the CU vectors.
1187 // For each CU vector, include one entry for the count at the
1188 // beginning of the vector.
1189 unsigned int cu_vector_count = this->cu_vector_list_.size();
1190 unsigned int cu_vector_size = 0;
1191 this->cu_vector_offsets_ = new off_t[cu_vector_count];
1192 for (unsigned int i = 0; i < cu_vector_count; ++i)
1194 Cu_vector* cu_vec = this->cu_vector_list_[i];
1195 cu_vector_offsets_[i] = cu_vector_size;
1196 cu_vector_size += gdb_index_offset_size * (cu_vec->size() + 1);
1199 // Assign relative offsets to each portion of the index,
1200 // and find the total size of the section.
1201 section_size_type data_size = gdb_index_hdr_size;
1202 data_size += this->comp_units_.size() * gdb_index_cu_size;
1203 this->tu_offset_ = data_size;
1204 data_size += this->type_units_.size() * gdb_index_tu_size;
1205 this->addr_offset_ = data_size;
1206 for (unsigned int i = 0; i < this->ranges_.size(); ++i)
1207 data_size += this->ranges_[i].ranges->size() * gdb_index_addr_size;
1208 this->symtab_offset_ = data_size;
1209 data_size += this->gdb_symtab_->capacity() * gdb_index_sym_size;
1210 this->cu_pool_offset_ = data_size;
1211 data_size += cu_vector_size;
1212 this->stringpool_offset_ = data_size;
1213 data_size += this->stringpool_.get_strtab_size();
1215 this->set_data_size(data_size);
1218 // Write the data to the file.
1221 Gdb_index::do_write(Output_file* of)
1223 const off_t off = this->offset();
1224 const off_t oview_size = this->data_size();
1225 unsigned char* const oview = of->get_output_view(off, oview_size);
1226 unsigned char* pov = oview;
1228 // Write the file header.
1229 // (1) Version number.
1230 elfcpp::Swap<32, false>::writeval(pov, gdb_index_version);
1232 // (2) Offset of the CU list.
1233 elfcpp::Swap<32, false>::writeval(pov, gdb_index_hdr_size);
1235 // (3) Offset of the types CU list.
1236 elfcpp::Swap<32, false>::writeval(pov, this->tu_offset_);
1238 // (4) Offset of the address area.
1239 elfcpp::Swap<32, false>::writeval(pov, this->addr_offset_);
1241 // (5) Offset of the symbol table.
1242 elfcpp::Swap<32, false>::writeval(pov, this->symtab_offset_);
1244 // (6) Offset of the constant pool.
1245 elfcpp::Swap<32, false>::writeval(pov, this->cu_pool_offset_);
1248 gold_assert(pov - oview == gdb_index_hdr_size);
1250 // Write the CU list.
1251 unsigned int comp_units_count = this->comp_units_.size();
1252 for (unsigned int i = 0; i < comp_units_count; ++i)
1254 const Comp_unit& cu = this->comp_units_[i];
1255 elfcpp::Swap<64, false>::writeval(pov, cu.cu_offset);
1256 elfcpp::Swap<64, false>::writeval(pov + 8, cu.cu_length);
1260 gold_assert(pov - oview == this->tu_offset_);
1262 // Write the types CU list.
1263 for (unsigned int i = 0; i < this->type_units_.size(); ++i)
1265 const Type_unit& tu = this->type_units_[i];
1266 elfcpp::Swap<64, false>::writeval(pov, tu.tu_offset);
1267 elfcpp::Swap<64, false>::writeval(pov + 8, tu.type_offset);
1268 elfcpp::Swap<64, false>::writeval(pov + 16, tu.type_signature);
1272 gold_assert(pov - oview == this->addr_offset_);
1274 // Write the address area.
1275 for (unsigned int i = 0; i < this->ranges_.size(); ++i)
1277 int cu_index = this->ranges_[i].cu_index;
1278 // Translate negative indexes, which refer to a TU, to a
1279 // logical index into a concatenated CU/TU list.
1281 cu_index = comp_units_count + (-1 - cu_index);
1282 Relobj* object = this->ranges_[i].object;
1283 const Dwarf_range_list& ranges = *this->ranges_[i].ranges;
1284 for (unsigned int j = 0; j < ranges.size(); ++j)
1286 const Dwarf_range_list::Range& range = ranges[j];
1288 if (range.shndx > 0)
1290 const Output_section* os = object->output_section(range.shndx);
1291 base = (os->address()
1292 + object->output_section_offset(range.shndx));
1294 elfcpp::Swap_aligned32<64, false>::writeval(pov, base + range.start);
1295 elfcpp::Swap_aligned32<64, false>::writeval(pov + 8,
1297 elfcpp::Swap<32, false>::writeval(pov + 16, cu_index);
1302 gold_assert(pov - oview == this->symtab_offset_);
1304 // Write the symbol table.
1305 for (unsigned int i = 0; i < this->gdb_symtab_->capacity(); ++i)
1307 const Gdb_symbol* sym = (*this->gdb_symtab_)[i];
1308 section_offset_type name_offset = 0;
1309 unsigned int cu_vector_offset = 0;
1312 name_offset = (this->stringpool_.get_offset_from_key(sym->name_key)
1313 + this->stringpool_offset_ - this->cu_pool_offset_);
1314 cu_vector_offset = this->cu_vector_offsets_[sym->cu_vector_index];
1316 elfcpp::Swap<32, false>::writeval(pov, name_offset);
1317 elfcpp::Swap<32, false>::writeval(pov + 4, cu_vector_offset);
1321 gold_assert(pov - oview == this->cu_pool_offset_);
1323 // Write the CU vectors into the constant pool.
1324 for (unsigned int i = 0; i < this->cu_vector_list_.size(); ++i)
1326 Cu_vector* cu_vec = this->cu_vector_list_[i];
1327 elfcpp::Swap<32, false>::writeval(pov, cu_vec->size());
1329 for (unsigned int j = 0; j < cu_vec->size(); ++j)
1331 int cu_index = (*cu_vec)[j].first;
1332 uint8_t flags = (*cu_vec)[j].second;
1334 cu_index = comp_units_count + (-1 - cu_index);
1335 cu_index |= flags << 24;
1336 elfcpp::Swap<32, false>::writeval(pov, cu_index);
1341 gold_assert(pov - oview == this->stringpool_offset_);
1343 // Write the strings into the constant pool.
1344 this->stringpool_.write_to_buffer(pov, oview_size - this->stringpool_offset_);
1346 of->write_output_view(off, oview_size, oview);
1349 // Print usage statistics.
1351 Gdb_index::print_stats()
1353 if (parameters->options().gdb_index())
1354 Gdb_index_info_reader::print_stats();
1357 } // End namespace gold.