From 37cc0caeca4c9a8552370040f4cfeaeceaa03369 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Wed, 18 Jul 2018 13:38:35 +0200 Subject: [PATCH] [gdb/exp] Interpret size of vla with unknown size as At -O3 -g -gstrict-dwarf, gcc generates for an optimized out vla 'a' a DW_TAG_variable with type DW_TAG_array_type containing one DW_TAG_subrange_type, but without DW_AT_upper_bound or DW_AT_count, which makes the upper bound value 'unknown': ... .uleb128 0x15 # (DIE (0x161) DW_TAG_variable) .long 0xec # DW_AT_abstract_origin .long 0x170 # DW_AT_type ... .uleb128 0xa # (DIE (0x170) DW_TAG_array_type) .long 0x110 # DW_AT_type .long 0x17f # DW_AT_sibling .uleb128 0x17 # (DIE (0x179) DW_TAG_subrange_type) .long 0xc6 # DW_AT_type .byte 0 # end of children of DIE 0x170 ... But gdb prints '0' for the size of 'a': ... /gdb ./vla-1.exe -batch -ex "b f1" -ex "run" -ex "p sizeof(a)" Breakpoint 1 at 0x4004c0: f1. (2 locations) Breakpoint 1, f1 (i=) at vla-1.c:18 18 } $1 = 0 ... while would be more appropriate. This patch fixes that in evaluate_subexp_for_sizeof. Build and reg-tested on x86_64-linux. 2018-07-28 Tom de Vries * eval.c (evaluate_subexp_for_sizeof): Interpret size of dynamic type with undefined upper bound as . * gdb.base/vla-optimized-out-o3-strict.exp: New file. --- gdb/ChangeLog | 5 +++ gdb/eval.c | 2 + gdb/testsuite/ChangeLog | 4 ++ .../gdb.base/vla-optimized-out-o3-strict.exp | 40 +++++++++++++++++++ 4 files changed, 51 insertions(+) create mode 100644 gdb/testsuite/gdb.base/vla-optimized-out-o3-strict.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index bee8bffb6ef..2c2763d03c1 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2018-07-28 Tom de Vries + + * eval.c (evaluate_subexp_for_sizeof): Interpret size of dynamic type + with undefined upper bound as . + 2018-07-27 Sergio Durigan Junior * gcore.in: Rename variable "name" to "prefix". Expand diff --git a/gdb/eval.c b/gdb/eval.c index 9db6e7c69da..0495a11bfd7 100644 --- a/gdb/eval.c +++ b/gdb/eval.c @@ -3145,6 +3145,8 @@ evaluate_subexp_for_sizeof (struct expression *exp, int *pos, { val = evaluate_subexp (NULL_TYPE, exp, pos, EVAL_NORMAL); type = value_type (val); + if (TYPE_HIGH_BOUND_UNDEFINED (TYPE_INDEX_TYPE (type))) + return allocate_optimized_out_value (size_type); } else (*pos) += 4; diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index f51e255e316..f3d212c3dda 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2018-07-28 Tom de Vries + + * gdb.base/vla-optimized-out-o3-strict.exp: New file. + 2018-07-26 Tom de Vries * gdb.base/vla-optimized-out.c: Add comment about origin of test-case. diff --git a/gdb/testsuite/gdb.base/vla-optimized-out-o3-strict.exp b/gdb/testsuite/gdb.base/vla-optimized-out-o3-strict.exp new file mode 100644 index 00000000000..81ada875b37 --- /dev/null +++ b/gdb/testsuite/gdb.base/vla-optimized-out-o3-strict.exp @@ -0,0 +1,40 @@ +# Copyright 2018 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 . + +# Check whether we can determine the size of an optimized-out vla. + +standard_testfile + +if { [prepare_for_testing "failed to prepare" $testfile vla-optimized-out.c \ + {debug optimize=-O3 additional_flags=-gstrict-dwarf}] } { + return -1 +} + +proc vla_optimized_out { } { + if ![runto f1] { + fail "can't run to f1" + return + } + + gdb_test "p a" \ + { = } \ + "printed optimized out vla" + + gdb_test "p sizeof (a)" \ + { = } \ + "printed optimized out size of optimized out vla" +} + +vla_optimized_out -- 2.30.2