From efba5c2319d6c25393e5cce9a2d30bbc0cb53123 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Thu, 16 Apr 2020 14:56:32 +0200 Subject: [PATCH] [gdb/symtab] Handle PU without import in "save gdb-index" Consider the test-case added in this patch, with resulting dwarf: ... Compilation Unit @ offset 0xc7: Length: 0x2c (32-bit) Version: 4 Abbrev Offset: 0x64 Pointer Size: 8 <0>: Abbrev Number: 2 (DW_TAG_partial_unit) DW_AT_language : 2 (non-ANSI C) DW_AT_name : imported_unit.c <1>: Abbrev Number: 3 (DW_TAG_base_type) DW_AT_byte_size : 4 DW_AT_encoding : 5 (signed) DW_AT_name : int <1>: Abbrev Number: 4 (DW_TAG_subprogram) DW_AT_name : main DW_AT_type : <0xe4> DW_AT_external : 1 <1>: Abbrev Number: 0 Compilation Unit @ offset 0xf7: Length: 0x2c (32-bit) Version: 4 Abbrev Offset: 0x85 Pointer Size: 8 <0><102>: Abbrev Number: 2 (DW_TAG_compile_unit) <103> DW_AT_language : 2 (non-ANSI C) <104> DW_AT_name : <1><111>: Abbrev Number: 3 (DW_TAG_subprogram) <112> DW_AT_abstract_origin: <0xeb> <116> DW_AT_low_pc : 0x4004a7 <11e> DW_AT_high_pc : 0x4004b2 <1><126>: Abbrev Number: 0 ... When run with target board cc-with-gdb-index, we run into: ... (gdb) break main warning: (Internal error: pc 0x4004a7 in read in CU, but not in symtab.) warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.) Breakpoint 1 at 0x4004ab (gdb) PASS: gdb.dwarf2/imported-unit-runto-main.exp: setting breakpoint at main run Starting program: /data/gdb_versions/devel/build/gdb/testsuite/outputs/gdb.dwarf2/imported-unit-runto-main/imported-unit-runto-main warning: (Internal error: pc 0x4004a7 in read in CU, but not in symtab.) warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.) Breakpoint 1, warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.) warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.) 0x00000000004004ab in main () warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.) (gdb) FAIL: gdb.dwarf2/imported-unit-runto-main.exp: running to main in runto ... Looking at the .gdb_index section contents using objdump --dwarf=gdb_index, we have: ... CU table: [ 0] 0x0 - 0x2d [ 1] 0x2e - 0xa4 [ 2] 0xa5 - 0xc6 [ 3] 0xf7 - 0x126 [ 4] 0x127 - 0x2de [ 5] 0x2df - 0x300 Address table: 00000000004004a7 00000000004004b2 4 Symbol table: [489] main: 4 [global, function] ... We see that both the main symbol, and main address range map to CU 4, which has offset range 0x127 - 0x2de, while main actually is contained in CU 3 at offset range 0xf7 - 0x126. This is caused by this continue in write_gdbindex, which triggers for the PU: ... /* 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 .gdb_index. */ if (psymtab == NULL) continue; ... The continue causes the PU to be skipped in the CU table (we can see that the PU offset range 0xc7-0xf6 is missing) but the references are not taking that into account. I've tried fixing this in the optimal way, by updating the references, but ran into trouble when follow_die_offset tries to find the CU for the inter-CU ref. Because the PU is missing from the CU table, dwarf2_find_containing_comp_unit bisects to the wrong CU. Fix this by not skipping the PU in the CU table. Build and reg-tested on x86_64-linux, with native and target boards cc-with-gdb-index, cc-with-dwz and cc-with-dwz-m. gdb/ChangeLog: 2020-04-16 Tom de Vries PR symtab/25791 * dwarf2/index-write.c (write_gdbindex): Generate CU table entries for CUs without psymtab. gdb/testsuite/ChangeLog: 2020-04-16 Tom de Vries PR symtab/25791 * gdb.dwarf2/gdb-add-index.exp (add_gdb_index): Move ... (ensure_gdb_index): and factor out and move ... * lib/gdb.exp (add_gdb_index, ensure_gdb_index): ... here. * gdb.dwarf2/imported-unit-runto-main.exp: New file. --- gdb/ChangeLog | 6 ++ gdb/dwarf2/index-write.c | 19 ++-- gdb/testsuite/ChangeLog | 8 ++ gdb/testsuite/gdb.dwarf2/gdb-add-index.exp | 40 +------- .../gdb.dwarf2/imported-unit-runto-main.exp | 92 +++++++++++++++++++ gdb/testsuite/lib/gdb.exp | 43 +++++++++ 6 files changed, 160 insertions(+), 48 deletions(-) create mode 100644 gdb/testsuite/gdb.dwarf2/imported-unit-runto-main.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 0130d06c9fc..b019ca9b461 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,9 @@ +2020-04-16 Tom de Vries + + PR symtab/25791 + * dwarf2/index-write.c (write_gdbindex): Generate CU table entries for + CUs without psymtab. + 2020-04-16 Kevin Buettner * python/python.c (do_start_initialization): Don't call diff --git a/gdb/dwarf2/index-write.c b/gdb/dwarf2/index-write.c index 8c933dc63b7..b6a13a0ca16 100644 --- a/gdb/dwarf2/index-write.c +++ b/gdb/dwarf2/index-write.c @@ -1426,18 +1426,15 @@ write_gdbindex (struct dwarf2_per_objfile *dwarf2_per_objfile, FILE *out_file, = 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 .gdb_index. */ - if (psymtab == NULL) - continue; - - if (psymtab->user == NULL) - recursively_write_psymbols (objfile, psymtab, &symtab, - psyms_seen, i); + if (psymtab != NULL) + { + if (psymtab->user == NULL) + recursively_write_psymbols (objfile, psymtab, &symtab, + psyms_seen, i); - const auto insertpair = cu_index_htab.emplace (psymtab, i); - gdb_assert (insertpair.second); + const auto insertpair = cu_index_htab.emplace (psymtab, i); + gdb_assert (insertpair.second); + } /* The all_comp_units list contains CUs read from the objfile as well as from the eventual dwz file. We need to place the entry in the diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index f12a5d78301..eaa96b06e76 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,11 @@ +2020-04-16 Tom de Vries + + PR symtab/25791 + * gdb.dwarf2/gdb-add-index.exp (add_gdb_index): Move ... + (ensure_gdb_index): and factor out and move ... + * lib/gdb.exp (add_gdb_index, ensure_gdb_index): ... here. + * gdb.dwarf2/imported-unit-runto-main.exp: New file. + 2020-04-16 Tom de Vries * gdb.base/maint-expand-symbols-header-file.exp: Set language before diff --git a/gdb/testsuite/gdb.dwarf2/gdb-add-index.exp b/gdb/testsuite/gdb.dwarf2/gdb-add-index.exp index 32d319f4756..708f4b13751 100644 --- a/gdb/testsuite/gdb.dwarf2/gdb-add-index.exp +++ b/gdb/testsuite/gdb.dwarf2/gdb-add-index.exp @@ -27,48 +27,14 @@ if { [prepare_for_testing "failed to prepare" "${testfile}" \ return -1 } -# Add a .gdb_index section to PROGRAM. -# PROGRAM is assumed to be the output of standard_output_file. -# Returns the 0 if there is a failure, otherwise 1. - -proc add_gdb_index { program } { - global srcdir GDB env BUILD_DATA_DIRECTORY - set contrib_dir "$srcdir/../contrib" - set env(GDB) "$GDB --data-directory=$BUILD_DATA_DIRECTORY" - set result [catch "exec $contrib_dir/gdb-add-index.sh $program" output] - if { $result != 0 } { - verbose -log "result is $result" - verbose -log "output is $output" - return 0 - } - - return 1 -} - -# Build a copy of the program with an index (.gdb_index/.debug_names). -# But only if the toolchain didn't already create one: gdb doesn't support -# building an index from a program already using one. - -set test "check if index present" -gdb_test_multiple "mt print objfiles ${testfile}" $test { - -re "gdb_index.*${gdb_prompt} $" { - set binfile_with_index $binfile - } - -re "debug_names.*${gdb_prompt} $" { - set binfile_with_index $binfile - } - -re "Psymtabs.*${gdb_prompt} $" { - if { [add_gdb_index $binfile] != "1" } { - return -1 - } - set binfile_with_index $binfile - } +if { [ensure_gdb_index $binfile] == -1 } { + return -1 } # Ok, we have a copy of $binfile with an index. # Restart gdb and verify the index was used. -clean_restart ${binfile_with_index} +clean_restart ${binfile} gdb_test "mt print objfiles ${testfile}" \ "(gdb_index|debug_names).*" \ "index used" diff --git a/gdb/testsuite/gdb.dwarf2/imported-unit-runto-main.exp b/gdb/testsuite/gdb.dwarf2/imported-unit-runto-main.exp new file mode 100644 index 00000000000..27946840534 --- /dev/null +++ b/gdb/testsuite/gdb.dwarf2/imported-unit-runto-main.exp @@ -0,0 +1,92 @@ +# Copyright 2020 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +load_lib dwarf.exp + +# This test can only be run on targets which support DWARF-2 and use gas. +if {![dwarf2_support]} { + return 0 +}; + +standard_testfile main.c .S + +set executable ${testfile} +set asm_file [standard_output_file ${srcfile2}] + +# We need to know the size of integer types in order to write some of the +# debugging info we'd like to generate. +if [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] { + return -1 +} + +# Create the DWARF. +Dwarf::assemble $asm_file { + declare_labels cu_label main_label int_label + declare_labels aaa_label + set int_size [get_sizeof "int" 4] + + global srcdir subdir srcfile + + extern main + + set main_range [function_range main ${srcdir}/${subdir}/${srcfile}] + set main_start [lindex $main_range 0] + set main_length [lindex $main_range 1] + + cu {} { + cu_label: partial_unit { + {language @DW_LANG_C} + {name "imported_unit.c"} + } { + int_label: base_type { + {byte_size $int_size sdata} + {encoding @DW_ATE_signed} + {name int} + } + + main_label: subprogram { + {name main} + {type :$int_label} + {external 1 flag} + } + } + } + + cu {} { + compile_unit { + {language @DW_LANG_C} + {name ""} + } { + subprogram { + {abstract_origin %$main_label} + {low_pc $main_start addr} + {high_pc "$main_start + $main_length" addr} + } + } + } +} + +if { [prepare_for_testing "failed to prepare" ${testfile} \ + [list $srcfile $asm_file] {nodebug}] } { + return -1 +} + +if { [ensure_gdb_index $binfile] == -1 } { + return -1 +} + +clean_restart ${binfile} + +runto main message diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp index 52687ad89ae..8418c3d8753 100644 --- a/gdb/testsuite/lib/gdb.exp +++ b/gdb/testsuite/lib/gdb.exp @@ -7038,5 +7038,48 @@ proc verify_psymtab_expanded { filename readin } { } } +# Add a .gdb_index section to PROGRAM. +# PROGRAM is assumed to be the output of standard_output_file. +# Returns the 0 if there is a failure, otherwise 1. + +proc add_gdb_index { program } { + global srcdir GDB env BUILD_DATA_DIRECTORY + set contrib_dir "$srcdir/../contrib" + set env(GDB) "$GDB --data-directory=$BUILD_DATA_DIRECTORY" + set result [catch "exec $contrib_dir/gdb-add-index.sh $program" output] + if { $result != 0 } { + verbose -log "result is $result" + verbose -log "output is $output" + return 0 + } + + return 1 +} + +# Add a .gdb_index section to PROGRAM, unless it alread has an index +# (.gdb_index/.debug_names). Gdb doesn't support building an index from a +# program already using one. Return 1 if a .gdb_index was added, return 0 +# if it already contained an index, and -1 if an error occurred. + +proc ensure_gdb_index { binfile } { + set testfile [file tail $binfile] + set test "check if index present" + gdb_test_multiple "mt print objfiles ${testfile}" $test { + -re -wrap "gdb_index.*" { + return 0 + } + -re -wrap "debug_names.*" { + return 0 + } + -re -wrap "Psymtabs.*" { + if { [add_gdb_index $binfile] != "1" } { + return -1 + } + return 1 + } + } + return -1 +} + # Always load compatibility stuff. load_lib future.exp -- 2.30.2