From ec673e648cf7b2fa6a03342b0bca3ed3855f002f Mon Sep 17 00:00:00 2001 From: Cary Coutant Date: Tue, 28 Jan 2014 15:35:47 -0800 Subject: [PATCH] Add .gdb_index version 7 support. This patch adds support for .gdb_index version 7, which adds several flag bits to the symbol index. It also fixes a problem where it did not handle compressed debug sections correctly. Tested with a google/gcc-4_8 branch compiler, which supports the -ggnu-pubnames option to generate .debug_gnu_pubnames/pubtypes tables. (We will submit that patch to GCC when stage 1 reopens.) 2014-01-28 Cary Coutant * gold/dwarf_reader.cc: include (for make_pair). (Dwarf_abbrev_table::do_read_abbrevs): Check for compressed debug sections. (Dwarf_ranges_table::read_ranges_table): Likewise. (Dwarf_pubnames_table::read_section): Check for GNU-style sections, and for compressed debug sections. (Dwarf_pubnames_table::read_header): Compute end address of table. (Dwarf_pubnames_table::next_name): Return flag_byte. Check for end of list by offset, not by offset == 0. (Dwarf_info_reader::do_read_string_table): Check for compressed debug sections. * gold/dwarf_reader.h (Dwarf_pubnames_table::Dwarf_pubnames_table): Initialize new data members. (Dwarf_pubnames_table::next_name): return flag_byte. (Dwarf_pubnames_table::end_of_table_): New data member. (Dwarf_pubnames_table::is_gnu_style_): New data member. * gold/gdb-index.cc (gdb_index_version): Update to version 7. (Gdb_index_info_reader::read_pubtable): Read flag_byte. (Gdb_index_info_reader::read_pubnames_and_pubtypes): Don't read skeleton type unit DIEs. (Gdb_index::add_symbol): Add flag_byte; adjust all callers. (Gdb_index::do_write): Write flag_byte. * gold/gdb-index.h (Gdb_index::add_symbol): Add flags parameter. (Gdb_index::Cu_vector): Store flags along with cu indexes. * gold/testsuite/gdb_index_test_3.sh: Allow versions 4-7. * gold/testsuite/gdb_index_test_comm.sh: Likewise. --- gold/ChangeLog | 31 ++++++++++++++ gold/dwarf_reader.cc | 59 +++++++++++++++++++-------- gold/dwarf_reader.h | 13 ++++-- gold/gdb-index.cc | 32 +++++++++++---- gold/gdb-index.h | 7 ++-- gold/testsuite/gdb_index_test_3.sh | 2 +- gold/testsuite/gdb_index_test_comm.sh | 2 +- 7 files changed, 111 insertions(+), 35 deletions(-) diff --git a/gold/ChangeLog b/gold/ChangeLog index a9b583bc820..d2c975e7da2 100644 --- a/gold/ChangeLog +++ b/gold/ChangeLog @@ -1,3 +1,34 @@ +2014-01-28 Cary Coutant + + Add .gdb_index version 7 support. + + * gold/dwarf_reader.cc: include (for make_pair). + (Dwarf_abbrev_table::do_read_abbrevs): Check for compressed + debug sections. + (Dwarf_ranges_table::read_ranges_table): Likewise. + (Dwarf_pubnames_table::read_section): Check for GNU-style + sections, and for compressed debug sections. + (Dwarf_pubnames_table::read_header): Compute end address of table. + (Dwarf_pubnames_table::next_name): Return flag_byte. Check + for end of list by offset, not by offset == 0. + (Dwarf_info_reader::do_read_string_table): Check for compressed + debug sections. + * gold/dwarf_reader.h (Dwarf_pubnames_table::Dwarf_pubnames_table): + Initialize new data members. + (Dwarf_pubnames_table::next_name): return flag_byte. + (Dwarf_pubnames_table::end_of_table_): New data member. + (Dwarf_pubnames_table::is_gnu_style_): New data member. + * gold/gdb-index.cc (gdb_index_version): Update to version 7. + (Gdb_index_info_reader::read_pubtable): Read flag_byte. + (Gdb_index_info_reader::read_pubnames_and_pubtypes): Don't + read skeleton type unit DIEs. + (Gdb_index::add_symbol): Add flag_byte; adjust all callers. + (Gdb_index::do_write): Write flag_byte. + * gold/gdb-index.h (Gdb_index::add_symbol): Add flags parameter. + (Gdb_index::Cu_vector): Store flags along with cu indexes. + * gold/testsuite/gdb_index_test_3.sh: Allow versions 4-7. + * gold/testsuite/gdb_index_test_comm.sh: Likewise. + 2014-01-08 H.J. Lu * version.cc (print_version): Update copyright year to 2014. diff --git a/gold/dwarf_reader.cc b/gold/dwarf_reader.cc index 3aad27f7b3e..a628c546408 100644 --- a/gold/dwarf_reader.cc +++ b/gold/dwarf_reader.cc @@ -23,6 +23,7 @@ #include "gold.h" #include +#include #include #include "elfcpp_swap.h" @@ -180,7 +181,7 @@ Dwarf_abbrev_table::do_read_abbrevs( for (unsigned int i = 1; i < object->shnum(); ++i) { std::string name = object->section_name(i); - if (name == ".debug_abbrev") + if (name == ".debug_abbrev" || name == ".zdebug_abbrev") { abbrev_shndx = i; // Correct the offset. For incremental update links, we have a @@ -317,7 +318,7 @@ Dwarf_ranges_table::read_ranges_table( for (unsigned int i = 1; i < object->shnum(); ++i) { std::string name = object->section_name(i); - if (name == ".debug_ranges") + if (name == ".debug_ranges" || name == ".zdebug_ranges") { ranges_shndx = i; this->output_section_offset_ = object->output_section_offset(i); @@ -486,24 +487,38 @@ Dwarf_pubnames_table::read_section(Relobj* object, const unsigned char* symtab, { section_size_type buffer_size; unsigned int shndx = 0; + const char* name = this->is_pubtypes_ ? "pubtypes" : "pubnames"; + const char* gnu_name = (this->is_pubtypes_ + ? "gnu_pubtypes" + : "gnu_pubnames"); - // Find the .debug_pubnames/pubtypes section. - const char* name = (this->is_pubtypes_ - ? ".debug_pubtypes" - : ".debug_pubnames"); for (unsigned int i = 1; i < object->shnum(); ++i) { - if (object->section_name(i) == name) + std::string section_name = object->section_name(i); + const char* section_name_suffix = section_name.c_str(); + if (is_prefix_of(".debug_", section_name_suffix)) + section_name_suffix += 7; + else if (is_prefix_of(".zdebug_", section_name_suffix)) + section_name_suffix += 8; + else + continue; + if (strcmp(section_name_suffix, name) == 0) + { + shndx = i; + this->output_section_offset_ = object->output_section_offset(i); + break; + } + else if (strcmp(section_name_suffix, gnu_name) == 0) { shndx = i; this->output_section_offset_ = object->output_section_offset(i); + this->is_gnu_style_ = true; break; } } if (shndx == 0) return false; - this->buffer_ = object->decompressed_section_contents(shndx, &buffer_size, &this->owns_buffer_); @@ -570,6 +585,7 @@ Dwarf_pubnames_table::read_header(off_t offset) this->unit_length_ = unit_length + 4; this->offset_size_ = 4; } + this->end_of_table_ = pinfo + unit_length; // Check the version. unsigned int version = this->dwinfo_->read_from_pointer<16>(pinfo); @@ -593,20 +609,27 @@ Dwarf_pubnames_table::read_header(off_t offset) // Read the next name from the set. const char* -Dwarf_pubnames_table::next_name() +Dwarf_pubnames_table::next_name(uint8_t* flag_byte) { const unsigned char* pinfo = this->pinfo_; - // Read the offset within the CU. If this is zero, we have reached - // the end of the list. - uint32_t offset; - if (this->offset_size_ == 4) - offset = this->dwinfo_->read_from_pointer<32>(&pinfo); - else - offset = this->dwinfo_->read_from_pointer<64>(&pinfo); - if (offset == 0) + // Check for end of list. The table should be terminated by an + // entry containing nothing but a DIE offset of 0. + if (pinfo + this->offset_size_ >= this->end_of_table_) return NULL; + // Skip the offset within the CU. If this is zero, but we're not + // at the end of the table, then we have a real pubnames entry + // whose DIE offset is 0 (likely to be a GCC bug). Since we + // don't actually use the DIE offset in building .gdb_index, + // it's harmless. + pinfo += this->offset_size_; + + if (this->is_gnu_style_) + *flag_byte = *pinfo++; + else + *flag_byte = 0; + // Return a pointer to the string at the current location, // and advance the pointer to the next entry. const char* ret = reinterpret_cast(pinfo); @@ -1366,7 +1389,7 @@ Dwarf_info_reader::do_read_string_table(unsigned int string_shndx) for (unsigned int i = 1; i < this->object_->shnum(); ++i) { std::string name = object->section_name(i); - if (name == ".debug_str") + if (name == ".debug_str" || name == ".zdebug_str") { string_shndx = i; this->string_output_section_offset_ = diff --git a/gold/dwarf_reader.h b/gold/dwarf_reader.h index bbd966730c1..3afc6e2409d 100644 --- a/gold/dwarf_reader.h +++ b/gold/dwarf_reader.h @@ -400,7 +400,8 @@ class Dwarf_pubnames_table public: Dwarf_pubnames_table(Dwarf_info_reader* dwinfo, bool is_pubtypes) : dwinfo_(dwinfo), buffer_(NULL), buffer_end_(NULL), owns_buffer_(false), - offset_size_(0), pinfo_(NULL), is_pubtypes_(is_pubtypes), + offset_size_(0), pinfo_(NULL), end_of_table_(NULL), + is_pubtypes_(is_pubtypes), is_gnu_style_(false), output_section_offset_(0), unit_length_(0), cu_offset_(0) { } @@ -431,9 +432,10 @@ class Dwarf_pubnames_table subsection_size() { return this->unit_length_; } - // Read the next name from the set. + // Read the next name from the set. If the pubname table is gnu-style, + // FLAG_BYTE is set to the high-byte of a gdb_index version 7 cu_index. const char* - next_name(); + next_name(uint8_t* flag_byte); private: // The Dwarf_info_reader, for reading data. @@ -447,8 +449,13 @@ class Dwarf_pubnames_table unsigned int offset_size_; // The current position within the buffer. const unsigned char* pinfo_; + // The end of the current pubnames table. + const unsigned char* end_of_table_; // TRUE if this is a .debug_pubtypes section. bool is_pubtypes_; + // Gnu-style pubnames table. This style has an extra flag byte between the + // offset and the name, and is used for generating version 7 of gdb-index. + bool is_gnu_style_; // For incremental update links, this will hold the offset of the // input section within the output section. Offsets read from // relocated data will be relative to the output section, and need diff --git a/gold/gdb-index.cc b/gold/gdb-index.cc index d42fbbd5b3b..1504abe6db6 100644 --- a/gold/gdb-index.cc +++ b/gold/gdb-index.cc @@ -32,7 +32,7 @@ namespace gold { -const int gdb_index_version = 5; +const int gdb_index_version = 7; // Sizes of various records in the .gdb_index section. const int gdb_index_offset_size = 4; @@ -436,7 +436,8 @@ Gdb_index_info_reader::visit_die(Dwarf_die* die, Dwarf_die* context) // If the DIE is not a declaration, add it to the index. std::string full_name = this->get_qualified_name(die, context); if (!full_name.empty()) - this->gdb_index_->add_symbol(this->cu_index_, full_name.c_str()); + this->gdb_index_->add_symbol(this->cu_index_, + full_name.c_str(), 0); } break; case elfcpp::DW_TAG_typedef: @@ -476,7 +477,7 @@ Gdb_index_info_reader::visit_die(Dwarf_die* die, Dwarf_die* context) full_name = this->get_qualified_name(die, context); if (!full_name.empty()) this->gdb_index_->add_symbol(this->cu_index_, - full_name.c_str()); + full_name.c_str(), 0); } // We're interested in the children only for namespaces and @@ -870,11 +871,12 @@ Gdb_index_info_reader::read_pubtable(Dwarf_pubnames_table* table, off_t offset) return false; while (true) { - const char* name = table->next_name(); + uint8_t flag_byte; + const char* name = table->next_name(&flag_byte); if (name == NULL) break; - this->gdb_index_->add_symbol(this->cu_index_, name); + this->gdb_index_->add_symbol(this->cu_index_, name, flag_byte); } return true; } @@ -885,6 +887,14 @@ Gdb_index_info_reader::read_pubtable(Dwarf_pubnames_table* table, off_t offset) bool Gdb_index_info_reader::read_pubnames_and_pubtypes(Dwarf_die* die) { + // If this is a skeleton debug-type die (generated via + // -gsplit-dwarf), then the associated pubnames should have been + // read along with the corresponding CU. In any case, there isn't + // enough info inside to build a gdb index entry. + if (die->tag() == elfcpp::DW_TAG_type_unit + && die->string_attribute(elfcpp::DW_AT_GNU_dwo_name)) + return true; + // We use stmt_list_off as a unique identifier for the // compilation unit and its associated type units. unsigned int shndx; @@ -1112,7 +1122,7 @@ Gdb_index::scan_debug_info(bool is_type_unit, // Add a symbol. void -Gdb_index::add_symbol(int cu_index, const char* sym_name) +Gdb_index::add_symbol(int cu_index, const char* sym_name, uint8_t flags) { unsigned int hash = mapped_index_string_hash( reinterpret_cast(sym_name)); @@ -1139,8 +1149,10 @@ Gdb_index::add_symbol(int cu_index, const char* sym_name) // if it's not already on the list. We only need to // check the last added entry. Cu_vector* cu_vec = this->cu_vector_list_[found->cu_vector_index]; - if (cu_vec->size() == 0 || cu_vec->back() != cu_index) - cu_vec->push_back(cu_index); + if (cu_vec->size() == 0 + || cu_vec->back().first != cu_index + || cu_vec->back().second != flags) + cu_vec->push_back(std::make_pair(cu_index, flags)); } // Return TRUE if we have already processed the pubnames associated @@ -1317,9 +1329,11 @@ Gdb_index::do_write(Output_file* of) pov += 4; for (unsigned int j = 0; j < cu_vec->size(); ++j) { - int cu_index = (*cu_vec)[j]; + int cu_index = (*cu_vec)[j].first; + uint8_t flags = (*cu_vec)[j].second; if (cu_index < 0) cu_index = comp_units_count + (-1 - cu_index); + cu_index |= flags << 24; elfcpp::Swap<32, false>::writeval(pov, cu_index); pov += 4; } diff --git a/gold/gdb-index.h b/gold/gdb-index.h index 5d9fe476452..babde4a355d 100644 --- a/gold/gdb-index.h +++ b/gold/gdb-index.h @@ -89,9 +89,10 @@ class Gdb_index : public Output_section_data this->ranges_.push_back(Per_cu_range_list(object, cu_index, ranges)); } - // Add a symbol. + // Add a symbol. FLAGS are the gdb_index version 7 flags to be stored in + // the high-byte of the cu_index field. void - add_symbol(int cu_index, const char* sym_name); + add_symbol(int cu_index, const char* sym_name, uint8_t flags); // Return the offset into the pubnames table for the cu at the given // offset. @@ -213,7 +214,7 @@ class Gdb_index : public Output_section_data { return this->name_key == symbol->name_key; } }; - typedef std::vector Cu_vector; + typedef std::vector > Cu_vector; typedef Unordered_map Pubname_offset_map; Pubname_offset_map cu_pubname_map_; diff --git a/gold/testsuite/gdb_index_test_3.sh b/gold/testsuite/gdb_index_test_3.sh index bd1500b83a1..1a239e0f524 100755 --- a/gold/testsuite/gdb_index_test_3.sh +++ b/gold/testsuite/gdb_index_test_3.sh @@ -37,7 +37,7 @@ check() STDOUT=gdb_index_test_3.stdout -check $STDOUT "^Version [45]" +check $STDOUT "^Version [4-7]" # Look for the symbols we know should be in the symbol table. diff --git a/gold/testsuite/gdb_index_test_comm.sh b/gold/testsuite/gdb_index_test_comm.sh index 4ab07b3c3a2..a9d3d4f8ffa 100755 --- a/gold/testsuite/gdb_index_test_comm.sh +++ b/gold/testsuite/gdb_index_test_comm.sh @@ -37,7 +37,7 @@ check() STDOUT="$1" -check $STDOUT "^Version [45]" +check $STDOUT "^Version [4-7]" # Look for the symbols we know should be in the symbol table. -- 2.30.2