From 2bd3e4b8d2580839a457e221d4e1e09105248215 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Tue, 2 Feb 2021 08:37:45 +0100 Subject: [PATCH] [gdb/symtab] Fix assert in write_one_signatured_type When running test-case gdb.dwarf2/fission-reread.exp with target board cc-with-gdb-index, we run into an abort during the generation of the gdb-index by cc-with-tweaks.sh: ... build/gdb/testsuite/cache/gdb.sh: line 1: 27275 Aborted (core dumped) ... This can be reproduced on the command line like this: ... $ gdb -batch ./outputs/gdb.dwarf2/fission-reread/fission-reread \ -ex 'save gdb-index ./outputs/gdb.dwarf2/fission-reread' warning: Could not find DWO TU fission-reread.dwo(0x9022f1ceac7e8b19) \ referenced by TU at offset 0x0 [in module fission-reread] warning: Could not find DWO CU fission-reread.dwo(0x807060504030201) \ referenced by CU at offset 0x561 [in module fission-reread] Aborted (core dumped) ... The abort is a segfault due to a using a nullptr psymtab in write_one_signatured_type. The problem is that we're trying to write index entries for the type unit with signature: ... (gdb) p /x entry->signature $2 = 0x9022f1ceac7e8b19 ... which is a skeleton type unit: ... Contents of the .debug_types section: Compilation Unit @ offset 0x0: Length: 0x4a (32-bit) Version: 4 Abbrev Offset: 0x165 Pointer Size: 4 Signature: 0x9022f1ceac7e8b19 Type Offset: 0x0 <0><17>: Abbrev Number: 2 (DW_TAG_type_unit) <18> DW_AT_comp_dir : /tmp/src/gdb/testsuite <2f> DW_AT_GNU_dwo_name: fission-reread.dwo <42> DW_AT_GNU_pubnames: 0x0 <46> DW_AT_GNU_pubtypes: 0x0 <4a> DW_AT_GNU_addr_base: 0x0 ... referring to a .dwo file, but as the warnings show, the .dwo file is not found. Fix this by skipping the type unit in write_one_signatured_type if psymtab == nullptr. Tested on x86_64-linux. gdb/ChangeLog: 2021-02-02 Tom de Vries PR symtab/24620 * dwarf2/index-write.c (write_one_signatured_type): Skip if psymtab == nullptr. gdb/testsuite/ChangeLog: 2021-02-02 Tom de Vries PR symtab/24620 * gdb.dwarf2/fission-reread.exp: Add test-case. --- gdb/ChangeLog | 6 ++++++ gdb/dwarf2/index-write.c | 8 ++++++++ gdb/testsuite/ChangeLog | 5 +++++ gdb/testsuite/gdb.dwarf2/fission-reread.exp | 15 +++++++++++++++ 4 files changed, 34 insertions(+) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 7323a13e0f2..0592c8643d6 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2021-02-02 Tom de Vries + + PR symtab/24620 + * dwarf2/index-write.c (write_one_signatured_type): Skip if + psymtab == nullptr. + 2021-02-01 Andrew Burgess * Makefile.in (HFILES_NO_SRCDIR): Add corefile.h. diff --git a/gdb/dwarf2/index-write.c b/gdb/dwarf2/index-write.c index 66781feaf46..a7b9ae66cae 100644 --- a/gdb/dwarf2/index-write.c +++ b/gdb/dwarf2/index-write.c @@ -616,6 +616,14 @@ write_one_signatured_type (void **slot, void *d) struct signatured_type *entry = (struct signatured_type *) *slot; partial_symtab *psymtab = entry->per_cu.v.psymtab; + if (psymtab == nullptr) + { + /* We can end up here when processing a skeleton CU referring to a + .dwo file that hasn't been found. There's not much we can do in + such a case, so skip this CU. */ + return 1; + } + write_psymbols (info->symtab, info->psyms_seen, psymtab->global_psymbols, info->cu_index, 0); diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index a557765c4b6..0f3f445b8f2 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2021-02-02 Tom de Vries + + PR symtab/24620 + * gdb.dwarf2/fission-reread.exp: Add test-case. + 2021-02-01 Tom de Vries * gdb.dwarf2/fission-base.S: Pass -DDWO=$dwo. diff --git a/gdb/testsuite/gdb.dwarf2/fission-reread.exp b/gdb/testsuite/gdb.dwarf2/fission-reread.exp index b97c48ad1b3..58132794ee7 100644 --- a/gdb/testsuite/gdb.dwarf2/fission-reread.exp +++ b/gdb/testsuite/gdb.dwarf2/fission-reread.exp @@ -56,3 +56,18 @@ pass $testfile gdb_unload # If we get this far gdb didn't crash, nor did an error occur. pass "$testfile - unload" + +# Test-case for PR24620: Delete the .dwo file and verify that +# save gdb-index doesn't crash. +remote_file target delete $dwo +clean_restart $binfile +set output_dir [standard_output_file ""] +set cmd "save gdb-index" +gdb_test_multiple "$cmd $output_dir" $cmd { + -re -wrap "Cannot use an index to create the index.*" { + unsupported $gdb_test_name + } + -re "^$cmd \[^\r\n\]*\r\n$gdb_prompt $" { + pass $gdb_test_name + } +} -- 2.30.2