From 437afbb81e3a04cbd933fc534a50c686eaa63b19 Mon Sep 17 00:00:00 2001 From: Jan Kratochvil Date: Fri, 8 Dec 2017 22:44:10 +0000 Subject: [PATCH] DWARF-5: .debug_names index producer This adds a new "-dwarf-5" switch to "save gdb-index" that makes it generate index files with DWARF-5 .debug_names/.debug_str sections instead of GDB's own .gdb_index. We should probably add a command line option to contrib/gdb-add-index.sh (incl. cc-with-tweaks.sh) for the new -dwarf-5 GDB option, and a new target board to make it more convenient to exercise this. To be done later. gdb/ChangeLog 2017-12-08 Jan Kratochvil Pedro Alves * contrib/gdb-add-index.sh (index): Rename to ... (index4): ... here. (index5, debugstr, debugstrmerge, debugstrerr): New variables. Support also .debug_names and .debug_str. * dwarf2read.c: Include cmath, set, list. (INDEX_SUFFIX): Rename to ... (INDEX4_SUFFIX): ... here. (INDEX5_SUFFIX, DEBUG_STR_SUFFIX): New. (file_write(FILE *, const void *, size_t)): New. (file_write(FILE *, const std::vector &)): New. (data_buf::append_unsigned_leb128, data_buf::empty): New. (data_buf::file_write): Use ::file_write. (data_buf::c_str, dwarf5_djb_hash, debug_names) (check_dwarf64_offsets): New. (psyms_seen_size, write_gdbindex): New from write_psymtabs_to_index code. (dwarf5_gdb_augmentation, write_debug_names, assert_file_size) (enum dw_index_kind): New. (write_psymtabs_to_index): New parameter index_kind. Support filename_str and out_file_str. Move code to write_gdbindex, possibly call write_debug_names. (save_gdb_index_command): New parameter -dwarf-5. (_initialize_dwarf2_read): Document the new parameter -dwarf-5. gdb/doc/ChangeLog 2017-12-08 Jan Kratochvil * gdb.texinfo (Index Files): Document .debug_names and -dwarf-5. -- gdb/contrib/gdb-add-index.sh | 53 ++ gdb/doc/gdb.texinfo | 24 + gdb/dwarf2read.c | 919 ++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 935 insertions(+), 61 deletions(-) --- gdb/ChangeLog | 27 ++ gdb/contrib/gdb-add-index.sh | 53 +- gdb/doc/ChangeLog | 4 + gdb/doc/gdb.texinfo | 24 +- gdb/dwarf2read.c | 918 +++++++++++++++++++++++++++++++++-- 5 files changed, 965 insertions(+), 61 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index e90a3f01b3c..0f26785f16c 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,30 @@ +2017-12-08 Jan Kratochvil + Pedro Alves + + * contrib/gdb-add-index.sh (index): Rename to ... + (index4): ... here. + (index5, debugstr, debugstrmerge, debugstrerr): New variables. + Support also .debug_names and .debug_str. + * dwarf2read.c: Include cmath, set, list. + (INDEX_SUFFIX): Rename to ... + (INDEX4_SUFFIX): ... here. + (INDEX5_SUFFIX, DEBUG_STR_SUFFIX): New. + (file_write(FILE *, const void *, size_t)): New. + (file_write(FILE *, const std::vector &)): New. + (data_buf::append_unsigned_leb128, data_buf::empty): New. + (data_buf::file_write): Use ::file_write. + (data_buf::c_str, dwarf5_djb_hash, debug_names) + (check_dwarf64_offsets): New. + (psyms_seen_size, write_gdbindex): New from + write_psymtabs_to_index code. + (dwarf5_gdb_augmentation, write_debug_names, assert_file_size) + (enum dw_index_kind): New. + (write_psymtabs_to_index): New parameter index_kind. Support + filename_str and out_file_str. Move code to write_gdbindex, + possibly call write_debug_names. + (save_gdb_index_command): New parameter -dwarf-5. + (_initialize_dwarf2_read): Document the new parameter -dwarf-5. + 2017-12-08 Jan Kratochvil Pedro Alves diff --git a/gdb/contrib/gdb-add-index.sh b/gdb/contrib/gdb-add-index.sh index 0cd4ce3c9d6..02b17f0fc06 100755 --- a/gdb/contrib/gdb-add-index.sh +++ b/gdb/contrib/gdb-add-index.sh @@ -37,11 +37,15 @@ fi dir="${file%/*}" test "$dir" = "$file" && dir="." -index="${file}.gdb-index" +index4="${file}.gdb-index" +index5="${file}.debug_names" +debugstr="${file}.debug_str" +debugstrmerge="${file}.debug_str.merge" +debugstrerr="${file}.debug_str.err" -rm -f $index +rm -f $index4 $index5 $debugstr $debugstrmerge $debugstrerr # Ensure intermediate index file is removed when we exit. -trap "rm -f $index" 0 +trap "rm -f $index4 $index5 $debugstr $debugstrmerge $debugstrerr" 0 $GDB --batch -nx -iex 'set auto-load no' \ -ex "file $file" -ex "save gdb-index $dir" || { @@ -57,9 +61,46 @@ $GDB --batch -nx -iex 'set auto-load no' \ # already stripped binary, it's a no-op. status=0 -if test -f "$index"; then - $OBJCOPY --add-section .gdb_index="$index" \ - --set-section-flags .gdb_index=readonly "$file" "$file" +if test -f "$index4" -a -f "$index5"; then + echo "$myname: Both index types were created for $file" 1>&2 + status=1 +elif test -f "$index4" -o -f "$index5"; then + if test -f "$index4"; then + index="$index4" + section=".gdb_index" + else + index="$index5" + section=".debug_names" + fi + debugstradd=false + debugstrupdate=false + if test -s "$debugstr"; then + if ! $OBJCOPY --dump-section .debug_str="$debugstrmerge" "$file" /dev/null \ + 2>$debugstrerr; then + cat >&2 $debugstrerr + exit 1 + fi + if grep -q "can't dump section '.debug_str' - it does not exist" \ + $debugstrerr; then + debugstradd=true + else + debugstrupdate=true + cat >&2 $debugstrerr + fi + cat "$debugstr" >>"$debugstrmerge" + fi + + $OBJCOPY --add-section $section="$index" \ + --set-section-flags $section=readonly \ + $(if $debugstradd; then \ + echo --add-section .debug_str="$debugstrmerge"; \ + echo --set-section-flags .debug_str=readonly; \ + fi; \ + if $debugstrupdate; then \ + echo --update-section .debug_str="$debugstrmerge"; \ + fi) \ + "$file" "$file" + status=$? else echo "$myname: No index was created for $file" 1>&2 diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index df294d6874f..771064041ce 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,7 @@ +2017-12-08 Jan Kratochvil + + * gdb.texinfo (Index Files): Document .debug_names and -dwarf-5. + 2017-12-07 Keith Seitz * gdb.texinfo (Symbols): Document "set print type nested-type-limit" diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index 1e4ef98738e..062f01d5ff2 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -19565,12 +19565,16 @@ using @command{objcopy}. To create an index file, use the @code{save gdb-index} command: @table @code -@item save gdb-index @var{directory} +@item save gdb-index [-dwarf-5] @var{directory} @kindex save gdb-index -Create an index file for each symbol file currently known by -@value{GDBN}. Each file is named after its corresponding symbol file, -with @samp{.gdb-index} appended, and is written into the given -@var{directory}. +Create index files for all symbol files currently known by +@value{GDBN}. For each known @var{symbol-file}, this command by +default creates it produces a single file +@file{@var{symbol-file}.gdb-index}. If you invoke this command with +the @option{-dwarf-5} option, it produces 2 files: +@file{@var{symbol-file}.debug_names} and +@file{@var{symbol-file}.debug_str}. The files are created in the +given @var{directory}. @end table Once you have created an index file you can merge it into your symbol @@ -19581,6 +19585,16 @@ $ objcopy --add-section .gdb_index=symfile.gdb-index \ --set-section-flags .gdb_index=readonly symfile symfile @end smallexample +Or for @code{-dwarf-5}: + +@smallexample +$ objcopy --dump-section .debug_str=symfile.debug_str.new symfile +$ cat symfile.debug_str >>symfile.debug_str.new +$ objcopy --add-section .debug_names=symfile.gdb-index \ + --set-section-flags .debug_names=readonly \ + --update-section .debug_str=symfile.debug_str.new symfile symfile +@end smallexample + @value{GDBN} will normally ignore older versions of @file{.gdb_index} sections that have been deprecated. Usually they are deprecated because they are missing a new feature or have performance issues. diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c index 68ddbb1dbda..a9daf1f3bc7 100644 --- a/gdb/dwarf2read.c +++ b/gdb/dwarf2read.c @@ -82,6 +82,12 @@ #include #include #include "selftest.h" +#include +#include +#include + +typedef struct symbol *symbolp; +DEF_VEC_P (symbolp); /* When == 1, print basic high level tracing messages. When > 1, be more verbose. @@ -2267,7 +2273,9 @@ attr_value_as_address (struct attribute *attr) } /* The suffix for an index file. */ -#define INDEX_SUFFIX ".gdb-index" +#define INDEX4_SUFFIX ".gdb-index" +#define INDEX5_SUFFIX ".debug_names" +#define DEBUG_STR_SUFFIX ".debug_str" /* See declaration. */ @@ -24232,6 +24240,25 @@ dwarf2_per_objfile_free (struct objfile *objfile, void *d) /* The "save gdb-index" command. */ +/* Write SIZE bytes from the buffer pointed to by DATA to FILE, with + error checking. */ + +static void +file_write (FILE *file, const void *data, size_t size) +{ + if (fwrite (data, 1, size, file) != size) + error (_("couldn't data write to file")); +} + +/* Write the contents of VEC to FILE, with error checking. */ + +template +static void +file_write (FILE *file, const std::vector &vec) +{ + file_write (file, vec.data (), vec.size () * sizeof (vec[0])); +} + /* In-memory buffer to prepare data to be written later to a file. */ class data_buf { @@ -24253,6 +24280,21 @@ class data_buf std::copy (cstr, cstr + size, grow (size)); } + /* Store INPUT as ULEB128 to the end of buffer. */ + void append_unsigned_leb128 (ULONGEST input) + { + for (;;) + { + gdb_byte output = input & 0x7f; + input >>= 7; + if (input) + output |= 0x80; + append_data (output); + if (input == 0) + break; + } + } + /* Accept a host-format integer in VAL and append it to the buffer as a target-format integer which is LEN bytes long. */ void append_uint (size_t len, bfd_endian byte_order, ULONGEST val) @@ -24266,11 +24308,16 @@ class data_buf return m_vec.size (); } + /* Return true iff the buffer is empty. */ + bool empty () const + { + return m_vec.empty (); + } + /* Write the buffer to FILE. */ void file_write (FILE *file) const { - if (::fwrite (m_vec.data (), 1, m_vec.size (), file) != m_vec.size ()) - error (_("couldn't write data to file")); + ::file_write (file, m_vec); } private: @@ -24419,6 +24466,13 @@ class c_str_view return strcmp (m_cstr, other.m_cstr) == 0; } + /* Return the underlying C string. Note, the returned string is + only a reference with lifetime of this object. */ + const char *c_str () const + { + return m_cstr; + } + private: friend class c_str_view_hasher; const char *const m_cstr; @@ -24771,38 +24825,596 @@ recursively_write_psymbols (struct objfile *objfile, 1); } -/* Create an index file for OBJFILE in the directory DIR. */ +/* Symbol name hashing function as specified by DWARF-5. */ -static void -write_psymtabs_to_index (struct objfile *objfile, const char *dir) +static uint32_t +dwarf5_djb_hash (const char *str_) { - if (dwarf2_per_objfile->using_index) - error (_("Cannot use an index to create the index")); + const unsigned char *str = (const unsigned char *) str_; - if (VEC_length (dwarf2_section_info_def, dwarf2_per_objfile->types) > 1) - error (_("Cannot make an index when the file has multiple .debug_types sections")); + /* Note: tolower here ignores UTF-8, which isn't fully compliant. + See http://dwarfstd.org/ShowIssue.php?issue=161027.1. */ - if (!objfile->psymtabs || !objfile->psymtabs_addrmap) - return; + uint32_t hash = 5381; + while (int c = *str++) + hash = hash * 33 + tolower (c); + return hash; +} - struct stat st; - if (stat (objfile_name (objfile), &st) < 0) - perror_with_name (objfile_name (objfile)); +/* DWARF-5 .debug_names builder. */ +class debug_names +{ +public: + debug_names (bool is_dwarf64, bfd_endian dwarf5_byte_order) + : m_dwarf5_byte_order (dwarf5_byte_order), + m_dwarf32 (dwarf5_byte_order), + m_dwarf64 (dwarf5_byte_order), + m_dwarf (is_dwarf64 + ? static_cast (m_dwarf64) + : static_cast (m_dwarf32)), + m_name_table_string_offs (m_dwarf.name_table_string_offs), + m_name_table_entry_offs (m_dwarf.name_table_entry_offs) + {} - std::string filename (std::string (dir) + SLASH_STRING - + lbasename (objfile_name (objfile)) + INDEX_SUFFIX); + /* Insert one symbol. */ + void insert (const partial_symbol *psym, int cu_index, bool is_static) + { + const int dwarf_tag = psymbol_tag (psym); + if (dwarf_tag == 0) + return; + const char *const name = SYMBOL_SEARCH_NAME (psym); + const auto insertpair + = m_name_to_value_set.emplace (c_str_view (name), + std::set ()); + std::set &value_set = insertpair.first->second; + value_set.emplace (symbol_value (dwarf_tag, cu_index, is_static)); + } - FILE *out_file = gdb_fopen_cloexec (filename.c_str (), "wb").release (); - if (!out_file) - error (_("Can't open `%s' for writing"), filename.c_str ()); + /* Build all the tables. All symbols must be already inserted. + This function does not call file_write, caller has to do it + afterwards. */ + void build () + { + /* Verify the build method has not be called twice. */ + gdb_assert (m_abbrev_table.empty ()); + const size_t name_count = m_name_to_value_set.size (); + m_bucket_table.resize + (std::pow (2, std::ceil (std::log2 (name_count * 4 / 3)))); + m_hash_table.reserve (name_count); + m_name_table_string_offs.reserve (name_count); + m_name_table_entry_offs.reserve (name_count); - /* Order matters here; we want FILE to be closed before FILENAME is - unlinked, because on MS-Windows one cannot delete a file that is - still open. (Don't call anything here that might throw until - file_closer is created.) */ - gdb::unlinker unlink_file (filename.c_str ()); - gdb_file_up close_out_file (out_file); + /* Map each hash of symbol to its name and value. */ + struct hash_it_pair + { + uint32_t hash; + decltype (m_name_to_value_set)::const_iterator it; + }; + std::vector> bucket_hash; + bucket_hash.resize (m_bucket_table.size ()); + for (decltype (m_name_to_value_set)::const_iterator it + = m_name_to_value_set.cbegin (); + it != m_name_to_value_set.cend (); + ++it) + { + const char *const name = it->first.c_str (); + const uint32_t hash = dwarf5_djb_hash (name); + hash_it_pair hashitpair; + hashitpair.hash = hash; + hashitpair.it = it; + auto &slot = bucket_hash[hash % bucket_hash.size()]; + slot.push_front (std::move (hashitpair)); + } + for (size_t bucket_ix = 0; bucket_ix < bucket_hash.size (); ++bucket_ix) + { + const std::forward_list &hashitlist + = bucket_hash[bucket_ix]; + if (hashitlist.empty ()) + continue; + uint32_t &bucket_slot = m_bucket_table[bucket_ix]; + /* The hashes array is indexed starting at 1. */ + store_unsigned_integer (reinterpret_cast (&bucket_slot), + sizeof (bucket_slot), m_dwarf5_byte_order, + m_hash_table.size () + 1); + for (const hash_it_pair &hashitpair : hashitlist) + { + m_hash_table.push_back (0); + store_unsigned_integer (reinterpret_cast + (&m_hash_table.back ()), + sizeof (m_hash_table.back ()), + m_dwarf5_byte_order, hashitpair.hash); + const c_str_view &name = hashitpair.it->first; + const std::set &value_set = hashitpair.it->second; + m_name_table_string_offs.push_back_reorder + (m_debugstrlookup.lookup (name.c_str ())); + m_name_table_entry_offs.push_back_reorder (m_entry_pool.size ()); + gdb_assert (!value_set.empty ()); + for (const symbol_value &value : value_set) + { + int &idx = m_indexkey_to_idx[index_key (value.dwarf_tag, + value.is_static)]; + if (idx == 0) + { + idx = m_idx_next++; + m_abbrev_table.append_unsigned_leb128 (idx); + m_abbrev_table.append_unsigned_leb128 (value.dwarf_tag); + m_abbrev_table.append_unsigned_leb128 (DW_IDX_compile_unit); + m_abbrev_table.append_unsigned_leb128 (DW_FORM_udata); + m_abbrev_table.append_unsigned_leb128 (value.is_static + ? DW_IDX_GNU_internal + : DW_IDX_GNU_external); + m_abbrev_table.append_unsigned_leb128 (DW_FORM_flag_present); + /* Terminate attributes list. */ + m_abbrev_table.append_unsigned_leb128 (0); + m_abbrev_table.append_unsigned_leb128 (0); + } + + m_entry_pool.append_unsigned_leb128 (idx); + m_entry_pool.append_unsigned_leb128 (value.cu_index); + } + + /* Terminate the list of CUs. */ + m_entry_pool.append_unsigned_leb128 (0); + } + } + gdb_assert (m_hash_table.size () == name_count); + + /* Terminate tags list. */ + m_abbrev_table.append_unsigned_leb128 (0); + } + + /* Return .debug_names bucket count. This must be called only after + calling the build method. */ + uint32_t bucket_count () const + { + /* Verify the build method has been already called. */ + gdb_assert (!m_abbrev_table.empty ()); + const uint32_t retval = m_bucket_table.size (); + + /* Check for overflow. */ + gdb_assert (retval == m_bucket_table.size ()); + return retval; + } + + /* Return .debug_names names count. This must be called only after + calling the build method. */ + uint32_t name_count () const + { + /* Verify the build method has been already called. */ + gdb_assert (!m_abbrev_table.empty ()); + const uint32_t retval = m_hash_table.size (); + + /* Check for overflow. */ + gdb_assert (retval == m_hash_table.size ()); + return retval; + } + + /* Return number of bytes of .debug_names abbreviation table. This + must be called only after calling the build method. */ + uint32_t abbrev_table_bytes () const + { + gdb_assert (!m_abbrev_table.empty ()); + return m_abbrev_table.size (); + } + + /* Recurse into all "included" dependencies and store their symbols + as if they appeared in this psymtab. */ + void recursively_write_psymbols + (struct objfile *objfile, + struct partial_symtab *psymtab, + std::unordered_set &psyms_seen, + int cu_index) + { + for (int i = 0; i < psymtab->number_of_dependencies; ++i) + if (psymtab->dependencies[i]->user != NULL) + recursively_write_psymbols (objfile, psymtab->dependencies[i], + psyms_seen, cu_index); + + write_psymbols (psyms_seen, + &objfile->global_psymbols[psymtab->globals_offset], + psymtab->n_global_syms, cu_index, false); + write_psymbols (psyms_seen, + &objfile->static_psymbols[psymtab->statics_offset], + psymtab->n_static_syms, cu_index, true); + } + + /* Return number of bytes the .debug_names section will have. This + must be called only after calling the build method. */ + size_t bytes () const + { + /* Verify the build method has been already called. */ + gdb_assert (!m_abbrev_table.empty ()); + size_t expected_bytes = 0; + expected_bytes += m_bucket_table.size () * sizeof (m_bucket_table[0]); + expected_bytes += m_hash_table.size () * sizeof (m_hash_table[0]); + expected_bytes += m_name_table_string_offs.bytes (); + expected_bytes += m_name_table_entry_offs.bytes (); + expected_bytes += m_abbrev_table.size (); + expected_bytes += m_entry_pool.size (); + return expected_bytes; + } + + /* Write .debug_names to FILE_NAMES and .debug_str addition to + FILE_STR. This must be called only after calling the build + method. */ + void file_write (FILE *file_names, FILE *file_str) const + { + /* Verify the build method has been already called. */ + gdb_assert (!m_abbrev_table.empty ()); + ::file_write (file_names, m_bucket_table); + ::file_write (file_names, m_hash_table); + m_name_table_string_offs.file_write (file_names); + m_name_table_entry_offs.file_write (file_names); + m_abbrev_table.file_write (file_names); + m_entry_pool.file_write (file_names); + m_debugstrlookup.file_write (file_str); + } + +private: + + /* Storage for symbol names mapping them to their .debug_str section + offsets. */ + class debug_str_lookup + { + public: + + /* Object costructor to be called for current DWARF2_PER_OBJFILE. + All .debug_str section strings are automatically stored. */ + debug_str_lookup () + : m_abfd (dwarf2_per_objfile->objfile->obfd) + { + dwarf2_read_section (dwarf2_per_objfile->objfile, + &dwarf2_per_objfile->str); + if (dwarf2_per_objfile->str.buffer == NULL) + return; + for (const gdb_byte *data = dwarf2_per_objfile->str.buffer; + data < (dwarf2_per_objfile->str.buffer + + dwarf2_per_objfile->str.size);) + { + const char *const s = reinterpret_cast (data); + const auto insertpair + = m_str_table.emplace (c_str_view (s), + data - dwarf2_per_objfile->str.buffer); + if (!insertpair.second) + complaint (&symfile_complaints, + _("Duplicate string \"%s\" in " + ".debug_str section [in module %s]"), + s, bfd_get_filename (m_abfd)); + data += strlen (s) + 1; + } + } + + /* Return offset of symbol name S in the .debug_str section. Add + such symbol to the section's end if it does not exist there + yet. */ + size_t lookup (const char *s) + { + const auto it = m_str_table.find (c_str_view (s)); + if (it != m_str_table.end ()) + return it->second; + const size_t offset = (dwarf2_per_objfile->str.size + + m_str_add_buf.size ()); + m_str_table.emplace (c_str_view (s), offset); + m_str_add_buf.append_cstr0 (s); + return offset; + } + + /* Append the end of the .debug_str section to FILE. */ + void file_write (FILE *file) const + { + m_str_add_buf.file_write (file); + } + + private: + std::unordered_map m_str_table; + bfd *const m_abfd; + + /* Data to add at the end of .debug_str for new needed symbol names. */ + data_buf m_str_add_buf; + }; + + /* Container to map used DWARF tags to their .debug_names abbreviation + tags. */ + class index_key + { + public: + index_key (int dwarf_tag_, bool is_static_) + : dwarf_tag (dwarf_tag_), is_static (is_static_) + { + } + + bool + operator== (const index_key &other) const + { + return dwarf_tag == other.dwarf_tag && is_static == other.is_static; + } + + const int dwarf_tag; + const bool is_static; + }; + + /* Provide std::unordered_map::hasher for index_key. */ + class index_key_hasher + { + public: + size_t + operator () (const index_key &key) const + { + return (std::hash() (key.dwarf_tag) << 1) | key.is_static; + } + }; + + /* Parameters of one symbol entry. */ + class symbol_value + { + public: + const int dwarf_tag, cu_index; + const bool is_static; + + symbol_value (int dwarf_tag_, int cu_index_, bool is_static_) + : dwarf_tag (dwarf_tag_), cu_index (cu_index_), is_static (is_static_) + {} + + bool + operator< (const symbol_value &other) const + { +#define X(n) \ + do \ + { \ + if (n < other.n) \ + return true; \ + if (n > other.n) \ + return false; \ + } \ + while (0) + X (dwarf_tag); + X (is_static); + X (cu_index); +#undef X + return false; + } + }; + + /* Abstract base class to unify DWARF-32 and DWARF-64 name table + output. */ + class offset_vec + { + protected: + const bfd_endian dwarf5_byte_order; + public: + explicit offset_vec (bfd_endian dwarf5_byte_order_) + : dwarf5_byte_order (dwarf5_byte_order_) + {} + + /* Call std::vector::reserve for NELEM elements. */ + virtual void reserve (size_t nelem) = 0; + + /* Call std::vector::push_back with store_unsigned_integer byte + reordering for ELEM. */ + virtual void push_back_reorder (size_t elem) = 0; + + /* Return expected output size in bytes. */ + virtual size_t bytes () const = 0; + + /* Write name table to FILE. */ + virtual void file_write (FILE *file) const = 0; + }; + + /* Template to unify DWARF-32 and DWARF-64 output. */ + template + class offset_vec_tmpl : public offset_vec + { + public: + explicit offset_vec_tmpl (bfd_endian dwarf5_byte_order_) + : offset_vec (dwarf5_byte_order_) + {} + + /* Implement offset_vec::reserve. */ + void reserve (size_t nelem) override + { + m_vec.reserve (nelem); + } + + /* Implement offset_vec::push_back_reorder. */ + void push_back_reorder (size_t elem) override + { + m_vec.push_back (elem); + /* Check for overflow. */ + gdb_assert (m_vec.back () == elem); + store_unsigned_integer (reinterpret_cast (&m_vec.back ()), + sizeof (m_vec.back ()), dwarf5_byte_order, elem); + } + + /* Implement offset_vec::bytes. */ + size_t bytes () const override + { + return m_vec.size () * sizeof (m_vec[0]); + } + + /* Implement offset_vec::file_write. */ + void file_write (FILE *file) const override + { + ::file_write (file, m_vec); + } + + private: + std::vector m_vec; + }; + + /* Base class to unify DWARF-32 and DWARF-64 .debug_names output + respecting name table width. */ + class dwarf + { + public: + offset_vec &name_table_string_offs, &name_table_entry_offs; + + dwarf (offset_vec &name_table_string_offs_, + offset_vec &name_table_entry_offs_) + : name_table_string_offs (name_table_string_offs_), + name_table_entry_offs (name_table_entry_offs_) + { + } + }; + + /* Template to unify DWARF-32 and DWARF-64 .debug_names output + respecting name table width. */ + template + class dwarf_tmpl : public dwarf + { + public: + explicit dwarf_tmpl (bfd_endian dwarf5_byte_order_) + : dwarf (m_name_table_string_offs, m_name_table_entry_offs), + m_name_table_string_offs (dwarf5_byte_order_), + m_name_table_entry_offs (dwarf5_byte_order_) + {} + + private: + offset_vec_tmpl m_name_table_string_offs; + offset_vec_tmpl m_name_table_entry_offs; + }; + + /* Try to reconstruct original DWARF tag for given partial_symbol. + This function is not DWARF-5 compliant but it is sufficient for + GDB as a DWARF-5 index consumer. */ + static int psymbol_tag (const struct partial_symbol *psym) + { + domain_enum domain = PSYMBOL_DOMAIN (psym); + enum address_class aclass = PSYMBOL_CLASS (psym); + + switch (domain) + { + case VAR_DOMAIN: + switch (aclass) + { + case LOC_BLOCK: + return DW_TAG_subprogram; + case LOC_TYPEDEF: + return DW_TAG_typedef; + case LOC_COMPUTED: + case LOC_CONST_BYTES: + case LOC_OPTIMIZED_OUT: + case LOC_STATIC: + return DW_TAG_variable; + case LOC_CONST: + /* Note: It's currently impossible to recognize psyms as enum values + short of reading the type info. For now punt. */ + return DW_TAG_variable; + default: + /* There are other LOC_FOO values that one might want to classify + as variables, but dwarf2read.c doesn't currently use them. */ + return DW_TAG_variable; + } + case STRUCT_DOMAIN: + return DW_TAG_structure_type; + default: + return 0; + } + } + + /* Call insert for all partial symbols and mark them in PSYMS_SEEN. */ + void write_psymbols (std::unordered_set &psyms_seen, + struct partial_symbol **psymp, int count, int cu_index, + bool is_static) + { + for (; count-- > 0; ++psymp) + { + struct partial_symbol *psym = *psymp; + + if (SYMBOL_LANGUAGE (psym) == language_ada) + error (_("Ada is not currently supported by the index")); + + /* Only add a given psymbol once. */ + if (psyms_seen.insert (psym).second) + insert (psym, cu_index, is_static); + } + } + + /* Store value of each symbol. */ + std::unordered_map, c_str_view_hasher> + m_name_to_value_set; + + /* Tables of DWARF-5 .debug_names. They are in object file byte + order. */ + std::vector m_bucket_table; + std::vector m_hash_table; + + const bfd_endian m_dwarf5_byte_order; + dwarf_tmpl m_dwarf32; + dwarf_tmpl m_dwarf64; + dwarf &m_dwarf; + offset_vec &m_name_table_string_offs, &m_name_table_entry_offs; + debug_str_lookup m_debugstrlookup; + + /* Map each used .debug_names abbreviation tag parameter to its + index value. */ + std::unordered_map m_indexkey_to_idx; + + /* Next unused .debug_names abbreviation tag for + m_indexkey_to_idx. */ + int m_idx_next = 1; + + /* .debug_names abbreviation table. */ + data_buf m_abbrev_table; + + /* .debug_names entry pool. */ + data_buf m_entry_pool; +}; + +/* Return iff any of the needed offsets does not fit into 32-bit + .debug_names section. */ + +static bool +check_dwarf64_offsets () +{ + for (int i = 0; i < dwarf2_per_objfile->n_comp_units; ++i) + { + const dwarf2_per_cu_data &per_cu = *dwarf2_per_objfile->all_comp_units[i]; + + if (to_underlying (per_cu.sect_off) >= (static_cast (1) << 32)) + return true; + } + for (int i = 0; i < dwarf2_per_objfile->n_type_units; ++i) + { + const signatured_type &sigtype = *dwarf2_per_objfile->all_type_units[i]; + const dwarf2_per_cu_data &per_cu = sigtype.per_cu; + + if (to_underlying (per_cu.sect_off) >= (static_cast (1) << 32)) + return true; + } + return false; +} + +/* The psyms_seen set is potentially going to be largish (~40k + elements when indexing a -g3 build of GDB itself). Estimate the + number of elements in order to avoid too many rehashes, which + require rebuilding buckets and thus many trips to + malloc/free. */ + +static size_t +psyms_seen_size () +{ + size_t psyms_count = 0; + for (int i = 0; i < dwarf2_per_objfile->n_comp_units; ++i) + { + struct dwarf2_per_cu_data *per_cu + = dwarf2_per_objfile->all_comp_units[i]; + struct partial_symtab *psymtab = per_cu->v.psymtab; + + if (psymtab != NULL && psymtab->user == NULL) + recursively_count_psymbols (psymtab, psyms_count); + } + /* Generating an index for gdb itself shows a ratio of + TOTAL_SEEN_SYMS/UNIQUE_SYMS or ~5. 4 seems like a good bet. */ + return psyms_count / 4; +} + +/* Write new .gdb_index section for OBJFILE into OUT_FILE. + Return how many bytes were expected to be written into OUT_FILE. */ + +static size_t +write_gdbindex (struct objfile *objfile, FILE *out_file) +{ mapped_symtab symtab; data_buf cu_list; @@ -24817,24 +25429,7 @@ write_psymtabs_to_index (struct objfile *objfile, const char *dir) work here. Also, the debug_types entries do not appear in all_comp_units, but only in their own hash table. */ - /* The psyms_seen set is potentially going to be largish (~40k - elements when indexing a -g3 build of GDB itself). Estimate the - number of elements in order to avoid too many rehashes, which - require rebuilding buckets and thus many trips to - malloc/free. */ - size_t psyms_count = 0; - for (int i = 0; i < dwarf2_per_objfile->n_comp_units; ++i) - { - struct dwarf2_per_cu_data *per_cu - = dwarf2_per_objfile->all_comp_units[i]; - struct partial_symtab *psymtab = per_cu->v.psymtab; - - if (psymtab != NULL && psymtab->user == NULL) - recursively_count_psymbols (psymtab, psyms_count); - } - /* Generating an index for gdb itself shows a ratio of - TOTAL_SEEN_SYMS/UNIQUE_SYMS or ~5. 4 seems like a good bet. */ - std::unordered_set psyms_seen (psyms_count / 4); + std::unordered_set psyms_seen (psyms_seen_size ()); for (int i = 0; i < dwarf2_per_objfile->n_comp_units; ++i) { struct dwarf2_per_cu_data *per_cu @@ -24920,22 +25515,241 @@ write_psymtabs_to_index (struct objfile *objfile, const char *dir) symtab_vec.file_write (out_file); constant_pool.file_write (out_file); + return total_len; +} + +/* DWARF-5 augmentation string for GDB's DW_IDX_GNU_* extension. */ +static const gdb_byte dwarf5_gdb_augmentation[] = { 'G', 'D', 'B', 0 }; + +/* Write a new .debug_names section for OBJFILE into OUT_FILE, write + needed addition to .debug_str section to OUT_FILE_STR. Return how + many bytes were expected to be written into OUT_FILE. */ + +static size_t +write_debug_names (struct objfile *objfile, FILE *out_file, FILE *out_file_str) +{ + const bool dwarf5_is_dwarf64 = check_dwarf64_offsets (); + const int dwarf5_offset_size = dwarf5_is_dwarf64 ? 8 : 4; + const enum bfd_endian dwarf5_byte_order + = gdbarch_byte_order (get_objfile_arch (objfile)); + + /* The CU list is already sorted, so we don't need to do additional + work here. Also, the debug_types entries do not appear in + all_comp_units, but only in their own hash table. */ + data_buf cu_list; + debug_names nametable (dwarf5_is_dwarf64, dwarf5_byte_order); + std::unordered_set psyms_seen (psyms_seen_size ()); + for (int i = 0; i < dwarf2_per_objfile->n_comp_units; ++i) + { + const dwarf2_per_cu_data *per_cu = dwarf2_per_objfile->all_comp_units[i]; + partial_symtab *psymtab = per_cu->v.psymtab; + + /* CU of a shared file from 'dwz -m' may be unused by this main + file. It may be referenced from a local scope but in such + case it does not need to be present in .debug_names. */ + if (psymtab == NULL) + continue; + + if (psymtab->user == NULL) + nametable.recursively_write_psymbols (objfile, psymtab, psyms_seen, i); + + cu_list.append_uint (dwarf5_offset_size, dwarf5_byte_order, + to_underlying (per_cu->sect_off)); + } + nametable.build (); + + /* No addr_vec - DWARF-5 uses .debug_aranges generated by GCC. */ + + data_buf types_cu_list; + for (int i = 0; i < dwarf2_per_objfile->n_type_units; ++i) + { + const signatured_type &sigtype = *dwarf2_per_objfile->all_type_units[i]; + const dwarf2_per_cu_data &per_cu = sigtype.per_cu; + + types_cu_list.append_uint (dwarf5_offset_size, dwarf5_byte_order, + to_underlying (per_cu.sect_off)); + } + + const offset_type bytes_of_header + = ((dwarf5_is_dwarf64 ? 12 : 4) + + 2 + 2 + 7 * 4 + + sizeof (dwarf5_gdb_augmentation)); + size_t expected_bytes = 0; + expected_bytes += bytes_of_header; + expected_bytes += cu_list.size (); + expected_bytes += types_cu_list.size (); + expected_bytes += nametable.bytes (); + data_buf header; + + if (!dwarf5_is_dwarf64) + { + const uint64_t size64 = expected_bytes - 4; + gdb_assert (size64 < 0xfffffff0); + header.append_uint (4, dwarf5_byte_order, size64); + } + else + { + header.append_uint (4, dwarf5_byte_order, 0xffffffff); + header.append_uint (8, dwarf5_byte_order, expected_bytes - 12); + } + + /* The version number. */ + header.append_uint (2, dwarf5_byte_order, 5); + + /* Padding. */ + header.append_uint (2, dwarf5_byte_order, 0); + + /* comp_unit_count - The number of CUs in the CU list. */ + header.append_uint (4, dwarf5_byte_order, dwarf2_per_objfile->n_comp_units); + + /* local_type_unit_count - The number of TUs in the local TU + list. */ + header.append_uint (4, dwarf5_byte_order, dwarf2_per_objfile->n_type_units); + + /* foreign_type_unit_count - The number of TUs in the foreign TU + list. */ + header.append_uint (4, dwarf5_byte_order, 0); + + /* bucket_count - The number of hash buckets in the hash lookup + table. */ + header.append_uint (4, dwarf5_byte_order, nametable.bucket_count ()); + + /* name_count - The number of unique names in the index. */ + header.append_uint (4, dwarf5_byte_order, nametable.name_count ()); + + /* abbrev_table_size - The size in bytes of the abbreviations + table. */ + header.append_uint (4, dwarf5_byte_order, nametable.abbrev_table_bytes ()); + + /* augmentation_string_size - The size in bytes of the augmentation + string. This value is rounded up to a multiple of 4. */ + static_assert (sizeof (dwarf5_gdb_augmentation) % 4 == 0, ""); + header.append_uint (4, dwarf5_byte_order, sizeof (dwarf5_gdb_augmentation)); + header.append_data (dwarf5_gdb_augmentation); + + gdb_assert (header.size () == bytes_of_header); + + header.file_write (out_file); + cu_list.file_write (out_file); + types_cu_list.file_write (out_file); + nametable.file_write (out_file, out_file_str); + + return expected_bytes; +} + +/* Assert that FILE's size is EXPECTED_SIZE. Assumes file's seek + position is at the end of the file. */ + +static void +assert_file_size (FILE *file, const char *filename, size_t expected_size) +{ + const auto file_size = ftell (file); + if (file_size == -1) + error (_("Can't get `%s' size"), filename); + gdb_assert (file_size == expected_size); +} + +/* An index variant. */ +enum dw_index_kind +{ + /* GDB's own .gdb_index format. */ + GDB_INDEX, + + /* DWARF5 .debug_names. */ + DEBUG_NAMES, +}; + +/* Create an index file for OBJFILE in the directory DIR. */ + +static void +write_psymtabs_to_index (struct objfile *objfile, const char *dir, + dw_index_kind index_kind) +{ + if (dwarf2_per_objfile->using_index) + error (_("Cannot use an index to create the index")); + + if (VEC_length (dwarf2_section_info_def, dwarf2_per_objfile->types) > 1) + error (_("Cannot make an index when the file has multiple .debug_types sections")); + + if (!objfile->psymtabs || !objfile->psymtabs_addrmap) + return; + + struct stat st; + if (stat (objfile_name (objfile), &st) < 0) + perror_with_name (objfile_name (objfile)); + + std::string filename (std::string (dir) + SLASH_STRING + + lbasename (objfile_name (objfile)) + + (index_kind == dw_index_kind::DEBUG_NAMES + ? INDEX5_SUFFIX : INDEX4_SUFFIX)); + + FILE *out_file = gdb_fopen_cloexec (filename.c_str (), "wb").release (); + if (!out_file) + error (_("Can't open `%s' for writing"), filename.c_str ()); + + /* Order matters here; we want FILE to be closed before FILENAME is + unlinked, because on MS-Windows one cannot delete a file that is + still open. (Don't call anything here that might throw until + file_closer is created.) */ + gdb::unlinker unlink_file (filename.c_str ()); + gdb_file_up close_out_file (out_file); + + if (index_kind == dw_index_kind::DEBUG_NAMES) + { + std::string filename_str (std::string (dir) + SLASH_STRING + + lbasename (objfile_name (objfile)) + + DEBUG_STR_SUFFIX); + FILE *out_file_str + = gdb_fopen_cloexec (filename_str.c_str (), "wb").release (); + if (!out_file_str) + error (_("Can't open `%s' for writing"), filename_str.c_str ()); + gdb::unlinker unlink_file_str (filename_str.c_str ()); + gdb_file_up close_out_file_str (out_file_str); + + const size_t total_len + = write_debug_names (objfile, out_file, out_file_str); + assert_file_size (out_file, filename.c_str (), total_len); + + /* We want to keep the file .debug_str file too. */ + unlink_file_str.keep (); + } + else + { + const size_t total_len + = write_gdbindex (objfile, out_file); + assert_file_size (out_file, filename.c_str (), total_len); + } + /* We want to keep the file. */ unlink_file.keep (); } /* Implementation of the `save gdb-index' command. - Note that the file format used by this command is documented in the - GDB manual. Any changes here must be documented there. */ + Note that the .gdb_index file format used by this command is + documented in the GDB manual. Any changes here must be documented + there. */ static void save_gdb_index_command (const char *arg, int from_tty) { struct objfile *objfile; + const char dwarf5space[] = "-dwarf-5 "; + dw_index_kind index_kind = dw_index_kind::GDB_INDEX; - if (!arg || !*arg) - error (_("usage: save gdb-index DIRECTORY")); + if (!arg) + arg = ""; + + arg = skip_spaces (arg); + if (strncmp (arg, dwarf5space, strlen (dwarf5space)) == 0) + { + index_kind = dw_index_kind::DEBUG_NAMES; + arg += strlen (dwarf5space); + arg = skip_spaces (arg); + } + + if (!*arg) + error (_("usage: save gdb-index [-dwarf-5] DIRECTORY")); ALL_OBJFILES (objfile) { @@ -24953,7 +25767,7 @@ save_gdb_index_command (const char *arg, int from_tty) TRY { - write_psymtabs_to_index (objfile, arg); + write_psymtabs_to_index (objfile, arg, index_kind); } CATCH (except, RETURN_MASK_ERROR) { @@ -25085,7 +25899,11 @@ Warning: This option must be enabled before gdb reads the file."), c = add_cmd ("gdb-index", class_files, save_gdb_index_command, _("\ Save a gdb-index file.\n\ -Usage: save gdb-index DIRECTORY"), +Usage: save gdb-index [-dwarf-5] DIRECTORY\n\ +\n\ +No options create one file with .gdb-index extension for pre-DWARF-5\n\ +compatible .gdb_index section. With -dwarf-5 creates two files with\n\ +extension .debug_names and .debug_str for DWARF-5 .debug_names section."), &save_cmdlist); set_cmd_completer (c, filename_completer);