From 42dc7699a26be0157c438dcaeb89da38287c6d2d Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Tue, 3 Jul 2018 11:06:45 +0200 Subject: [PATCH] [gdb/exp] Fix printing of type of optimized out vla Consider this snippet from gcc/testsuite/gcc.dg/guality/vla-1.c: ... int __attribute__((noinline)) f1 (int i) { char a[i + 1]; a[0] = 5; /* { dg-final { gdb-test .+1 "i" "5" } } */ return a[0]; /* { dg-final { gdb-test . "sizeof (a)" "6" } } */ } ... When we compile the test-case with -O1 -g, and query the size of optimized out vla 'a', we get: ... $ ./gdb -batch -ex "b f1" -ex "r" -ex "p sizeof (a)" vla-1.exe Breakpoint 1 at 0x4004a8: file vla-1.c, line 17. Breakpoint 1, f1 (i=i@entry=5) at vla-1.c:17 17 return a[0]; $1 = 0 ... while we expect a size of '6'. The problem is that default_read_var_value does not resolve the dynamic type of a variable if the variable is optimized out. This patch fixes that, and consequently gdb prints '6', as expected. Tested on x86_64-linux. 2018-07-18 Tom de Vries * findvar.c (default_read_var_value): Also resolve dynamic type for LOC_OPTIMIZED_OUT vars. * gdb.base/vla-optimized-out.c: New test. * gdb.base/vla-optimized-out.exp: New file. --- gdb/ChangeLog | 5 +++ gdb/findvar.c | 2 + gdb/testsuite/ChangeLog | 5 +++ gdb/testsuite/gdb.base/vla-optimized-out.c | 34 +++++++++++++++++ gdb/testsuite/gdb.base/vla-optimized-out.exp | 40 ++++++++++++++++++++ 5 files changed, 86 insertions(+) create mode 100644 gdb/testsuite/gdb.base/vla-optimized-out.c create mode 100644 gdb/testsuite/gdb.base/vla-optimized-out.exp diff --git a/gdb/ChangeLog b/gdb/ChangeLog index a30780a351a..65096d67203 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2018-07-18 Tom de Vries + + * findvar.c (default_read_var_value): Also resolve dynamic type for + LOC_OPTIMIZED_OUT vars. + 2018-07-18 Maciej W. Rozycki * mips-tdep.c (micromips_next_pc): Add SYSCALL instruction diff --git a/gdb/findvar.c b/gdb/findvar.c index 8ad5e25cb27..ebaff923a13 100644 --- a/gdb/findvar.c +++ b/gdb/findvar.c @@ -789,6 +789,8 @@ default_read_var_value (struct symbol *var, const struct block *var_block, break; case LOC_OPTIMIZED_OUT: + if (is_dynamic_type (type)) + type = resolve_dynamic_type (type, NULL, /* Unused address. */ 0); return allocate_optimized_out_value (type); default: diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index ec7a8197a52..dbd659d995a 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-07-18 Tom de Vries + + * gdb.base/vla-optimized-out.c: New test. + * gdb.base/vla-optimized-out.exp: New file. + 2018-07-13 Sergio Durigan Junior * lib/gdbserver-support.exp (gdbserver_start): Expect for the diff --git a/gdb/testsuite/gdb.base/vla-optimized-out.c b/gdb/testsuite/gdb.base/vla-optimized-out.c new file mode 100644 index 00000000000..913e8ea8670 --- /dev/null +++ b/gdb/testsuite/gdb.base/vla-optimized-out.c @@ -0,0 +1,34 @@ +/* This testcase is part of GDB, the GNU debugger. + + 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 . */ + +int __attribute__((noinline, noclone)) +f1 (int i) +{ + char a[i + 1]; + a[0] = 5; + return a[0]; +} + +int +main (void) +{ + volatile int j; + int i = 5; + asm volatile ("" : "=r" (i) : "0" (i)); + j = f1 (i); + return 0; +} diff --git a/gdb/testsuite/gdb.base/vla-optimized-out.exp b/gdb/testsuite/gdb.base/vla-optimized-out.exp new file mode 100644 index 00000000000..39abb795c89 --- /dev/null +++ b/gdb/testsuite/gdb.base/vla-optimized-out.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 $srcfile \ + {debug optimize=-O1}] } { + 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)" \ + { = 6} \ + "printed size of optimized out vla" +} + +vla_optimized_out -- 2.30.2