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[patch] Regressed TLS variables type (PR 13448)
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: gdb-patches at sourceware dot org
- Cc: Jerome Guitton <guitton at adacore dot com>, Ben Cohen <ben dot cohen at kognitio dot com>
- Date: Fri, 2 Dec 2011 02:07:48 +0100
- Subject: [patch] Regressed TLS variables type (PR 13448)
Hi,
http://sourceware.org/bugzilla/show_bug.cgi?id=13448
FAIL:
(gdb) print myname
$2 = 1936287860
PASS:
(gdb) print myname
$4 = "this is the main thread", '\000' <repeats 104 times>
9602d20e52e1a2291bd9edbdf98e4d82995a385e is the first bad commit
[RFA] Nullified garbage-collected global variables
http://sourceware.org/ml/gdb-patches/2010-07/msg00206.html
commit 9602d20e52e1a2291bd9edbdf98e4d82995a385e
Author: Jerome Guitton <guitton@adacore.com>
Date: Mon Jul 26 09:29:59 2010 +0000
gdb/
* dwarf2read.c (add_partial_symbol): Do not add a global variable if
its adress is null. Add comment to explain why.
(new_symbol): Ditto.
Added a testcase for the patch of Jul 2010 causing the regression.
Added a fix and a testcase for the regressed case.
The fix is not great, it further hacks up decode_locdesc, which I already
replaced before but later returned back by the revertion:
[patch#2] fetch result of locdesc expressions as integer (not address)
http://sourceware.org/ml/gdb-patches/2011-10/msg00225.html
After archer-jankratochvil-vla or its equivalent gets merged it may be fixed
better, at least the testcase exists for it now.
I will check it in in a day or so. It is a "recent" regression.
No regressions on {x86_64,x86_64-m32,i686}-fedora16-linux-gnu.
Thanks,
Jan
gdb/
2011-12-01 Jan Kratochvil <jan.kratochvil@redhat.com>
PR 13448
* dwarf2read.c (decode_locdesc): Handle DW_OP_const8u.
For DW_OP_GNU_push_tls_address increment the value, new comment for it.
gdb/testsuite/
2011-12-01 Jan Kratochvil <jan.kratochvil@redhat.com>
PR 13448
* gdb.dwarf2/dw2-var-zero-addr.S:: New file.
* gdb.dwarf2/dw2-var-zero-addr.exp:: New file.
* gdb.threads/tls-var-main.c:: New file.
* gdb.threads/tls-var.c:: New file.
* gdb.threads/tls-var.exp:: New file.
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -14667,6 +14667,11 @@ decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu)
i += 4;
break;
+ case DW_OP_const8u:
+ stack[++stacki] = read_8_bytes (objfile->obfd, &data[i]);
+ i += 8;
+ break;
+
case DW_OP_constu:
stack[++stacki] = read_unsigned_leb128 (NULL, (data + i),
&bytes_read);
@@ -14714,9 +14719,12 @@ decode_locdesc (struct dwarf_block *blk, struct dwarf2_cu *cu)
/* Nothing should follow this operator, so the top of stack would
be returned. */
/* This is valid for partial global symbols, but the variable's
- address will be bogus in the psymtab. */
+ address will be bogus in the psymtab. Make it always at least
+ non-zero to not look as a variable garbage collected by linker
+ which have DW_OP_addr 0. */
if (i < size)
dwarf2_complex_location_expr_complaint ();
+ stack[stacki]++;
break;
case DW_OP_GNU_uninit:
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-var-zero-addr.S
@@ -0,0 +1,92 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2011 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 <http://www.gnu.org/licenses/>. */
+
+ .data
+
+ .section .debug_info
+.Lcu1_begin:
+ /* CU header */
+ .4byte .Lcu1_end - .Lcu1_start /* Length of Compilation Unit */
+.Lcu1_start:
+ .2byte 2 /* DWARF Version */
+ .4byte .Labbrev1_begin /* Offset into abbrev section */
+ .byte 4 /* Pointer size */
+
+ /* CU die */
+ .uleb128 1 /* Abbrev: DW_TAG_compile_unit */
+ .ascii "dw2-var-zero-addr.c\0" /* DW_AT_name */
+ .ascii "GNU C 4.3.2\0" /* DW_AT_producer */
+ .byte 1 /* DW_AT_language (C) */
+
+.Ltype_uchar:
+ .uleb128 2 /* Abbrev: DW_TAG_base_type */
+ .ascii "int\0" /* DW_AT_name */
+ .byte 4 /* DW_AT_byte_size */
+ .byte 5 /* DW_AT_encoding */
+
+ .uleb128 3 /* Abbrev: DW_TAG_variable (location) */
+ .ascii "var\0" /* DW_AT_name */
+ .byte 2f - 1f /* DW_AT_location */
+1: .byte 3 /* DW_OP_addr */
+ .4byte 0 /* <addr> */
+2: .4byte .Ltype_uchar-.Lcu1_begin /* DW_AT_type */
+
+ .byte 0 /* End of children of CU */
+
+.Lcu1_end:
+
+/* Abbrev table */
+ .section .debug_abbrev
+.Labbrev1_begin:
+ .uleb128 1 /* Abbrev code */
+ .uleb128 0x11 /* DW_TAG_compile_unit */
+ .byte 1 /* has_children */
+ .uleb128 0x3 /* DW_AT_name */
+ .uleb128 0x8 /* DW_FORM_string */
+ .uleb128 0x25 /* DW_AT_producer */
+ .uleb128 0x8 /* DW_FORM_string */
+ .uleb128 0x13 /* DW_AT_language */
+ .uleb128 0xb /* DW_FORM_data1 */
+ .byte 0x0 /* Terminator */
+ .byte 0x0 /* Terminator */
+
+ .uleb128 2 /* Abbrev code */
+ .uleb128 0x24 /* DW_TAG_base_type */
+ .byte 0 /* has_children */
+ .uleb128 0x3 /* DW_AT_name */
+ .uleb128 0x8 /* DW_FORM_string */
+ .uleb128 0xb /* DW_AT_byte_size */
+ .uleb128 0xb /* DW_FORM_data1 */
+ .uleb128 0x3e /* DW_AT_encoding */
+ .uleb128 0xb /* DW_FORM_data1 */
+ .byte 0x0 /* Terminator */
+ .byte 0x0 /* Terminator */
+
+ .uleb128 3 /* Abbrev code (location) */
+ .uleb128 0x34 /* DW_TAG_variable */
+ .byte 0 /* has_children */
+ .uleb128 0x3 /* DW_AT_name */
+ .uleb128 0x8 /* DW_FORM_string */
+ .uleb128 0x2 /* DW_AT_location */
+ .uleb128 0xa /* DW_FORM_block1 */
+ .uleb128 0x49 /* DW_AT_type */
+ .uleb128 0x13 /* DW_FORM_ref4 */
+ .byte 0x0 /* Terminator */
+ .byte 0x0 /* Terminator */
+
+ .byte 0x0 /* Terminator */
+ .byte 0x0 /* Terminator */
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-var-zero-addr.exp
@@ -0,0 +1,29 @@
+# Copyright 2011 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 <http://www.gnu.org/licenses/>.
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+if {![dwarf2_support]} {
+ return 0
+}
+
+set testfile dw2-var-zero-addr
+if [prepare_for_testing ${testfile}.exp ${testfile} [list ${testfile}.S main.c] {nodebug}] {
+ return -1
+}
+
+# FAIL was: = (int *) 0x0
+# Such DIE record can be produced using: gcc -fdata-sections -Wl,-gc-sections
+gdb_test "print &var" {No symbol "var" in current context\.}
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/tls-var-main.c
@@ -0,0 +1,22 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2011 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 <http://www.gnu.org/licenses/>. */
+
+int
+main (void)
+{
+ return 0;
+}
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/tls-var.c
@@ -0,0 +1,23 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2011 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 <http://www.gnu.org/licenses/>. */
+
+#include <pthread.h>
+
+/* Place this variable to a separate CU (Compilation Unit) from main so that it
+ has delayed full symtab expansion. */
+
+__thread const char *tls_var = "hello";
--- /dev/null
+++ b/gdb/testsuite/gdb.threads/tls-var.exp
@@ -0,0 +1,40 @@
+# Copyright 2011 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 <http://www.gnu.org/licenses/>.
+
+set testfile tls-var
+set srcfile ${testfile}.c
+set srcmainfile ${testfile}-main.c
+set objfile ${objdir}/${subdir}/${testfile}.o
+set objmainfile ${objdir}/${subdir}/${testfile}-main.o
+set executable ${testfile}
+set binfile ${objdir}/${subdir}/${executable}
+
+if { [gdb_compile ${srcdir}/${subdir}/${srcfile} ${objfile} object {debug}] != ""
+ || [gdb_compile ${srcdir}/${subdir}/${srcmainfile} ${objmainfile} object {}] != ""
+ || [gdb_compile_pthreads "${objfile} ${objmainfile}" ${binfile} executable {}] != ""} {
+ return -1
+}
+
+clean_restart ${executable}
+
+if ![runto_main] {
+ return 0
+}
+
+# FAIL was: type = <thread local variable, no debug info>
+gdb_test "whatis tls_var" {type = const char \*}
+
+# FAIL was: $1 = 4195832
+gdb_test "print tls_var" { = 0x[0-9a-f]+ "hello"}