From a2860473ef13cfebcd9fddc067b7b36ca56c6b81 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Sat, 14 Sep 2024 14:09:35 +0200 Subject: [PATCH] [gdb/symtab] Revert "Change handling of DW_TAG_enumeration_type in DWARF scanner" After adding dwarf assembly to test-case gdb.dwarf2/enum-type.exp that adds this debug info: ... <1><11f>: Abbrev Number: 3 (DW_TAG_enumeration_type) <120> DW_AT_specification: <0x130> <2><124>: Abbrev Number: 4 (DW_TAG_enumerator) <125> DW_AT_name : val1 <12a> DW_AT_const_value : 1 <2><12b>: Abbrev Number: 0 <1><12c>: Abbrev Number: 5 (DW_TAG_namespace) <12d> DW_AT_name : ns <2><130>: Abbrev Number: 6 (DW_TAG_enumeration_type) <131> DW_AT_name : e <133> DW_AT_type : <0x118> <137> DW_AT_declaration : 1 ... I run into an assertion failure: ... (gdb) file enum-type^M Reading symbols from enum-type...^M cooked-index.h:214: internal-error: get_parent: \ Assertion `(flags & IS_PARENT_DEFERRED) == 0' failed.^M ... This was reported in PR32160 comment 1. This is a regression since commit 4e417d7bb1c ("Change handling of DW_TAG_enumeration_type in DWARF scanner"). Fix this by reverting the commit. [ Also drop the kfails for PR31900 and PR32158, which are regressions by that same commit. ] That allows us to look at the output of "maint print objfiles", and for val1 we get an entry without parent: ... [27] ((cooked_index_entry *) 0x7fbbb4002ef0) name: val1 canonical: val1 qualified: val1 DWARF tag: DW_TAG_enumerator flags: 0x0 [] DIE offset: 0x124 parent: ((cooked_index_entry *) 0) ... which is incorrect, as noted in that same comment, but an improvement over the assertion failure, and I don't think that ever worked. This is to be addressed in a follow-up patch. Reverting the commit begs the question: what was it trying to fix in the first place, and do we need a different fix? I've investigated this and filed PR32160 to track this. My guess is that the commit was based on a misunderstand of what we track in cooked_indexer::m_die_range_map. Each DIE has two types of parent DIEs: - a DIE that is the parent as indicated by the tree structure in which DIEs occur, and - a DIE that represent the parent scope. In most cases, these two are the same, but some times they're not. The debug info above demonstrates such a case. The DIE at 0x11f: - has a tree-parent: the DIE representing the CU, and - has a scope-parent: DIE 0x12c representing namespace ns. In cooked_indexer::m_die_range_map, we track scope-parents, and the commit tried to add a tree-parent instead. So, I don't think we need a different fix, and propose we backport the reversal for gdb 15.2. Tested on x86_64-linux. Approved-By: Tom Tromey Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31900 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32158 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=32160 --- gdb/dwarf2/read.c | 16 +++++----- gdb/testsuite/gdb.dwarf2/enum-type-c++.exp | 2 -- gdb/testsuite/gdb.dwarf2/enum-type.exp | 35 ++++++++++++++++++++++ 3 files changed, 44 insertions(+), 9 deletions(-) diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index e0dcf940402..bbd6bfbaf45 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -16471,12 +16471,6 @@ cooked_indexer::index_dies (cutu_reader *reader, flags &= ~IS_STATIC; flags |= parent_entry->flags & IS_STATIC; } - /* If the parent is an enum, but not an enum class, then use the - grandparent instead. */ - if (this_parent_entry != nullptr - && this_parent_entry->tag == DW_TAG_enumeration_type - && !is_enum_class) - this_parent_entry = this_parent_entry->get_parent (); if (abbrev->tag == DW_TAG_namespace && m_language == language_cplus @@ -16536,7 +16530,15 @@ cooked_indexer::index_dies (cutu_reader *reader, break; case DW_TAG_enumeration_type: - info_ptr = recurse (reader, info_ptr, this_entry, fully); + /* We need to recurse even for an anonymous enumeration. + Which scope we record as the parent scope depends on + whether we're reading an "enum class". If so, we use + the enum itself as the parent, yielding names like + "enum_class::enumerator"; otherwise we inject the + names into our own parent scope. */ + info_ptr = recurse (reader, info_ptr, + is_enum_class ? this_entry : parent_entry, + fully); continue; case DW_TAG_module: diff --git a/gdb/testsuite/gdb.dwarf2/enum-type-c++.exp b/gdb/testsuite/gdb.dwarf2/enum-type-c++.exp index a3dfb4d2f74..8bf737ec506 100644 --- a/gdb/testsuite/gdb.dwarf2/enum-type-c++.exp +++ b/gdb/testsuite/gdb.dwarf2/enum-type-c++.exp @@ -32,7 +32,6 @@ require {string equal [have_index $binfile] ""} set re_ws "\[ \t\]" # Regression test for PR31900. -setup_kfail "gdb/31900" *-*-* set val1 ns::A::val1 gdb_test_lines "maint print objfiles" \ "val1 has a parent" \ @@ -44,7 +43,6 @@ gdb_test_lines "maint print objfiles" \ gdb_test "print $val1" " = $val1" # Regression test for PR32158. -setup_kfail "gdb/32158" *-*-* set val2 ns::ec::val2 gdb_test_lines "maint print objfiles" \ "val2 has correct parent" \ diff --git a/gdb/testsuite/gdb.dwarf2/enum-type.exp b/gdb/testsuite/gdb.dwarf2/enum-type.exp index 394d287738b..b2b3dc6c828 100644 --- a/gdb/testsuite/gdb.dwarf2/enum-type.exp +++ b/gdb/testsuite/gdb.dwarf2/enum-type.exp @@ -65,6 +65,41 @@ Dwarf::assemble $asm_file { } } } + + cu {} { + DW_TAG_compile_unit { + {DW_AT_language @DW_LANG_C_plus_plus} + {DW_AT_name tmp.c} + {DW_AT_comp_dir /tmp} + } { + declare_labels integer_label forward + + integer_label: DW_TAG_base_type { + {DW_AT_byte_size 4 DW_FORM_sdata} + {DW_AT_encoding @DW_ATE_signed} + {DW_AT_name int} + } + + DW_TAG_enumeration_type { + {DW_AT_specification :$forward} + } { + DW_TAG_enumerator { + {DW_AT_name val1} + {DW_AT_const_value 1 DW_FORM_sdata} + } + } + + DW_TAG_namespace { + {DW_AT_name ns} + } { + forward: DW_TAG_enumeration_type { + {DW_AT_name e} + {DW_AT_type :$integer_label} + {DW_AT_declaration 1 flag} + } + } + } + } } if { [prepare_for_testing "failed to prepare" ${testfile} \ -- 2.39.5