[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><d2>: Abbrev Number: 2 (DW_TAG_partial_unit)
<d3> DW_AT_language : 2 (non-ANSI C)
<d4> DW_AT_name : imported_unit.c
<1><e4>: Abbrev Number: 3 (DW_TAG_base_type)
<e5> DW_AT_byte_size : 4
<e6> DW_AT_encoding : 5 (signed)
<e7> DW_AT_name : int
<1><eb>: Abbrev Number: 4 (DW_TAG_subprogram)
<ec> DW_AT_name : main
<f1> DW_AT_type : <0xe4>
<f5> DW_AT_external : 1
<1><f6>: 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 : <artificial>
<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.)
<repeat>
warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.)
<repeat>
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.)
<repeat>
warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.)
<repeat>
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.)
<repeat>
0x00000000004004ab in main ()
warning: (Internal error: pc 0x4004ab in read in CU, but not in symtab.)
<repeat>
(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 <tdevries@suse.de>
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 <tdevries@suse.de>
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.
This commit is contained in:
Tom de Vries
parent
97ed802d15
commit
efba5c2319
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@ -1,3 +1,9 @@
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2020-04-16 Tom de Vries <tdevries@suse.de>
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PR symtab/25791
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* dwarf2/index-write.c (write_gdbindex): Generate CU table entries for
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CUs without psymtab.
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2020-04-16 Kevin Buettner <kevinb@redhat.com>
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* python/python.c (do_start_initialization): Don't call
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@ -1426,18 +1426,15 @@ write_gdbindex (struct dwarf2_per_objfile *dwarf2_per_objfile, FILE *out_file,
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= dwarf2_per_objfile->all_comp_units[i];
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partial_symtab *psymtab = per_cu->v.psymtab;
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/* CU of a shared file from 'dwz -m' may be unused by this main file.
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It may be referenced from a local scope but in such case it does not
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need to be present in .gdb_index. */
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if (psymtab == NULL)
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continue;
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if (psymtab != NULL)
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{
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if (psymtab->user == NULL)
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recursively_write_psymbols (objfile, psymtab, &symtab,
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psyms_seen, i);
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if (psymtab->user == NULL)
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recursively_write_psymbols (objfile, psymtab, &symtab,
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psyms_seen, i);
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const auto insertpair = cu_index_htab.emplace (psymtab, i);
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gdb_assert (insertpair.second);
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const auto insertpair = cu_index_htab.emplace (psymtab, i);
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gdb_assert (insertpair.second);
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}
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/* The all_comp_units list contains CUs read from the objfile as well as
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from the eventual dwz file. We need to place the entry in the
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@ -1,3 +1,11 @@
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2020-04-16 Tom de Vries <tdevries@suse.de>
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PR symtab/25791
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* gdb.dwarf2/gdb-add-index.exp (add_gdb_index): Move ...
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(ensure_gdb_index): and factor out and move ...
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* lib/gdb.exp (add_gdb_index, ensure_gdb_index): ... here.
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* gdb.dwarf2/imported-unit-runto-main.exp: New file.
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2020-04-16 Tom de Vries <tdevries@suse.de>
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* gdb.base/maint-expand-symbols-header-file.exp: Set language before
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@ -27,48 +27,14 @@ if { [prepare_for_testing "failed to prepare" "${testfile}" \
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return -1
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}
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# Add a .gdb_index section to PROGRAM.
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# PROGRAM is assumed to be the output of standard_output_file.
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# Returns the 0 if there is a failure, otherwise 1.
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proc add_gdb_index { program } {
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global srcdir GDB env BUILD_DATA_DIRECTORY
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set contrib_dir "$srcdir/../contrib"
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set env(GDB) "$GDB --data-directory=$BUILD_DATA_DIRECTORY"
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set result [catch "exec $contrib_dir/gdb-add-index.sh $program" output]
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if { $result != 0 } {
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verbose -log "result is $result"
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verbose -log "output is $output"
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return 0
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}
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return 1
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}
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# Build a copy of the program with an index (.gdb_index/.debug_names).
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# But only if the toolchain didn't already create one: gdb doesn't support
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# building an index from a program already using one.
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set test "check if index present"
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gdb_test_multiple "mt print objfiles ${testfile}" $test {
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-re "gdb_index.*${gdb_prompt} $" {
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set binfile_with_index $binfile
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}
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-re "debug_names.*${gdb_prompt} $" {
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set binfile_with_index $binfile
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}
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-re "Psymtabs.*${gdb_prompt} $" {
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if { [add_gdb_index $binfile] != "1" } {
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return -1
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}
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set binfile_with_index $binfile
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}
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if { [ensure_gdb_index $binfile] == -1 } {
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return -1
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}
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# Ok, we have a copy of $binfile with an index.
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# Restart gdb and verify the index was used.
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clean_restart ${binfile_with_index}
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clean_restart ${binfile}
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gdb_test "mt print objfiles ${testfile}" \
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"(gdb_index|debug_names).*" \
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"index used"
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@ -0,0 +1,92 @@
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# Copyright 2020 Free Software Foundation, Inc.
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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load_lib dwarf.exp
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# This test can only be run on targets which support DWARF-2 and use gas.
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if {![dwarf2_support]} {
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return 0
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};
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standard_testfile main.c .S
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set executable ${testfile}
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set asm_file [standard_output_file ${srcfile2}]
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# We need to know the size of integer types in order to write some of the
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# debugging info we'd like to generate.
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if [prepare_for_testing "failed to prepare" ${testfile} ${srcfile}] {
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return -1
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}
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# Create the DWARF.
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Dwarf::assemble $asm_file {
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declare_labels cu_label main_label int_label
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declare_labels aaa_label
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set int_size [get_sizeof "int" 4]
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global srcdir subdir srcfile
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extern main
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set main_range [function_range main ${srcdir}/${subdir}/${srcfile}]
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set main_start [lindex $main_range 0]
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set main_length [lindex $main_range 1]
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cu {} {
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cu_label: partial_unit {
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{language @DW_LANG_C}
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{name "imported_unit.c"}
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} {
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int_label: base_type {
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{byte_size $int_size sdata}
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{encoding @DW_ATE_signed}
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{name int}
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}
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main_label: subprogram {
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{name main}
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{type :$int_label}
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{external 1 flag}
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}
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}
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}
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cu {} {
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compile_unit {
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{language @DW_LANG_C}
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{name "<artificial>"}
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} {
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subprogram {
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{abstract_origin %$main_label}
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{low_pc $main_start addr}
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{high_pc "$main_start + $main_length" addr}
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}
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}
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}
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}
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if { [prepare_for_testing "failed to prepare" ${testfile} \
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[list $srcfile $asm_file] {nodebug}] } {
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return -1
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}
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if { [ensure_gdb_index $binfile] == -1 } {
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return -1
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}
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clean_restart ${binfile}
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runto main message
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@ -7038,5 +7038,48 @@ proc verify_psymtab_expanded { filename readin } {
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}
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}
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# Add a .gdb_index section to PROGRAM.
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# PROGRAM is assumed to be the output of standard_output_file.
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# Returns the 0 if there is a failure, otherwise 1.
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proc add_gdb_index { program } {
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global srcdir GDB env BUILD_DATA_DIRECTORY
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set contrib_dir "$srcdir/../contrib"
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set env(GDB) "$GDB --data-directory=$BUILD_DATA_DIRECTORY"
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set result [catch "exec $contrib_dir/gdb-add-index.sh $program" output]
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if { $result != 0 } {
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verbose -log "result is $result"
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verbose -log "output is $output"
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return 0
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}
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return 1
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}
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# Add a .gdb_index section to PROGRAM, unless it alread has an index
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# (.gdb_index/.debug_names). Gdb doesn't support building an index from a
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# program already using one. Return 1 if a .gdb_index was added, return 0
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# if it already contained an index, and -1 if an error occurred.
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proc ensure_gdb_index { binfile } {
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set testfile [file tail $binfile]
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set test "check if index present"
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gdb_test_multiple "mt print objfiles ${testfile}" $test {
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-re -wrap "gdb_index.*" {
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return 0
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}
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-re -wrap "debug_names.*" {
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return 0
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}
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-re -wrap "Psymtabs.*" {
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if { [add_gdb_index $binfile] != "1" } {
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return -1
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}
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return 1
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}
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}
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return -1
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}
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# Always load compatibility stuff.
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load_lib future.exp
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