From aa5b8b8cc3c0246f00617ec23ebf15203fd75242 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Thu, 10 Aug 2023 21:16:30 +0200 Subject: [PATCH] [gdb/symtab] Fix off-by-one error in cooked_indexer::recurse Test-case gdb.dwarf2/pr13961.exp contains: ... <1><25>: Abbrev Number: 8 (DW_TAG_class_type) <26> DW_AT_specification: <0x2a> <1><2a>: Abbrev Number: 2 (DW_TAG_class_type) <2b> DW_AT_name : foo <2f> DW_AT_byte_size : 4 <30> DW_AT_decl_file : 1 <31> DW_AT_decl_line : 1 <32> DW_AT_sibling : <0x44> ... The DIE at 0x25 contains an intra-CU forward reference, and is deferred during DIE indexing in the cooked_index, by adding it to m_deferred_entries. The resulting cooked index entries are: ... [25] ((cooked_index_entry *) 0x333b5d0) name: foo canonical: foo qualified: foo DWARF tag: DW_TAG_class_type flags: 0x0 [] DIE offset: 0x2a parent: ((cooked_index_entry *) 0) [26] ((cooked_index_entry *) 0x333b630) name: foo canonical: foo qualified: foo::foo DWARF tag: DW_TAG_class_type flags: 0x0 [] DIE offset: 0x25 parent: ((cooked_index_entry *) 0x333b5d0) [foo] ... Notice that 0x2a is the parent of 0x25, and that this is why the qualified name of 0x25 is "foo::foo", which is incorrect, it's supposed to be "foo". The parent is set here in cooked_indexer::make_index: ... for (const auto &entry : m_deferred_entries) { void *obj = m_die_range_map.find (entry.spec_offset); cooked_index_entry *parent = static_cast (obj); m_index_storage->add (entry.die_offset, entry.tag, entry.flags, entry.name, parent, m_per_cu); } ... and AFAICT, we store in m_die_range_map the parent of the respective spec_offset DIE (though that's not clear from the comment describing it). So, the root cause of this is that when we lookup the parent for DIE 0x25, we get m_die_range_map.find (0x2a) == 0x2a. This is an off-by-one error, fixed in cooked_indexer::recurse by: ... - CORE_ADDR start = form_addr (parent_entry->die_offset, + CORE_ADDR start = form_addr (parent_entry->die_offset + 1, ... which gives us: ... [12] ((cooked_index_entry *) 0x41e21f0) name: foo canonical: foo qualified: foo DWARF tag: DW_TAG_class_type flags: 0x0 [] DIE offset: 0x25 parent: ((cooked_index_entry *) 0) [13] ((cooked_index_entry *) 0x41e2190) name: foo canonical: foo qualified: foo DWARF tag: DW_TAG_class_type flags: 0x0 [] DIE offset: 0x2a parent: ((cooked_index_entry *) 0) ... Tested on x86_64-linux. Approved-By: Tom Tromey PR symtab/30739 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30739 --- gdb/dwarf2/read.c | 4 +++- gdb/testsuite/gdb.dwarf2/pr13961.exp | 10 ++++++++++ 2 files changed, 13 insertions(+), 1 deletion(-) diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index dd4fac5..a64f82b 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -16477,7 +16477,9 @@ cooked_indexer::recurse (cutu_reader *reader, if (parent_entry != nullptr) { - CORE_ADDR start = form_addr (parent_entry->die_offset, + /* Both start and end are inclusive, so use both "+ 1" and "- 1" to + limit the range to the children of parent_entry. */ + CORE_ADDR start = form_addr (parent_entry->die_offset + 1, reader->cu->per_cu->is_dwz); CORE_ADDR end = form_addr (sect_offset (info_ptr - 1 - reader->buffer), reader->cu->per_cu->is_dwz); diff --git a/gdb/testsuite/gdb.dwarf2/pr13961.exp b/gdb/testsuite/gdb.dwarf2/pr13961.exp index 63c2595..08c38aa 100644 --- a/gdb/testsuite/gdb.dwarf2/pr13961.exp +++ b/gdb/testsuite/gdb.dwarf2/pr13961.exp @@ -34,3 +34,13 @@ gdb_test "break -q main" "Breakpoint.*at.*" # If we get this far gdb didn't crash. pass $testfile + +# Regression test for PR symtab/30739. +gdb_test_multiple "maint print objfiles $binfile" "no foo::foo" { + -re -wrap "\r\n *qualified: *foo::foo\r\n.*" { + fail $gdb_test_name + } + -re -wrap "" { + pass $gdb_test_name + } +} -- 2.7.4