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[patch] Limit DW_AT_comp_dir workaround only for gcc<=4.2
- From: Jan Kratochvil <jan dot kratochvil at redhat dot com>
- To: gdb-patches at sourceware dot org
- Date: Fri, 30 Nov 2012 18:39:46 +0100
- Subject: [patch] Limit DW_AT_comp_dir workaround only for gcc<=4.2
Hi,
there was commit
[commit] Handle files without DW_AT_comp_dir
Message-ID: <20070604123615.GA22533@caradoc.them.org>
http://sourceware.org/ml/gdb-patches/2007-06/msg00031.html
with further discusssion
Message-ID: <20120406123641.GA18063@host2.jankratochvil.net>
http://sourceware.org/ml/gdb-patches/2012-04/msg00105.html
That commit started to guess DW_AT_comp_dir if it was missing, because with
some GCC versions .debug_line could contain a relative directory. But
DW_AT_comp_dir is always only a best guess (dirname of CU's DW_AT_name), it
may be commonly wrong as shown in:
Subject: Re: [commit] Handle files without DW_AT_comp_dir
Message-ID: <20120409154750.GA15639@host2.jankratochvil.net>
http://sourceware.org/ml/gdb-patches/2012-04/msg00148.html
This guessed DW_AT_comp_dir (IMO) caused later confusion during implementation
of:
[patch] GDB 7.2: new feature for "backtrace" that cuts path to file (remain filename)
Message-ID: <BANLkTinD+9_Mkug8o2VhZ03L6XSriL_RKQ@mail.gmail.com>
http://sourceware.org/ml/gdb-patches/2011-06/msg00385.html
(with many replies on following months)
The GCC bug was fixed along a different feature, released first as gcc-4.3.0:
Subject: Debug info path remapping
Message-ID: <Pine.LNX.4.64.0707050046160.26969@digraph.polyomino.org.uk>
http://gcc.gnu.org/ml/gcc-patches/2007-07/msg00404.html
GCC GIT commit 5f1f2de5fe3f87b056e802102fcb975979845eff
I do not know since which GCC version had the missing DW_AT_comp_dir bug.
FSF GCC 3.3.5 PASS - .debug_line directory is absolute
FSF GCC 4.0.4 unknown, it fails to build for me
FSF GCC 4.2.5 20090330 (prerelease) FAIL - DW_AT_comp_dir missing
FSF GCC 4.3.6 PASS - DW_AT_comp_dir present
So I have kept the workaround there for anyhing < 4.3.0, it is at least no GDB
change for those GCC versions.
This is more a pre-requisite for the later new post of:
[patch] GDB 7.2: new feature for "backtrace" that cuts path to file (remain filename)
No regressions on {x86_64,x86_64-m32,i686}-fedora18-linux-gnu.
Thanks,
Jan
gdb/
2012-11-30 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2read.c (struct dwarf2_cu): New field producer_is_gcc_lt_4_3.
Update the comment for checked_producer.
(check_producer): New forward declaration.
(producer_is_gcc_lt_4_3): New function.
(find_file_and_directory): Simulate *COMP_DIR only for gcc < 4.3.
(check_producer): Initialize also PRODUCER_IS_GCC_LT_4_3.
gdb/testsuite/
2012-11-30 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdb.dwarf2/dw2-compdir-oldgcc.S: New file.
* gdb.dwarf2/dw2-compdir-oldgcc.exp: New file.
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index f4bd7a9..c0c0755 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -492,12 +492,13 @@ struct dwarf2_cu
unoptimized code. For a future better test see GCC PR other/32998. */
unsigned int has_loclist : 1;
- /* These cache the results for producer_is_gxx_lt_4_6 and producer_is_icc.
- CHECKED_PRODUCER is set if both PRODUCER_IS_GXX_LT_4_6 and PRODUCER_IS_ICC
- are valid. This information is cached because profiling CU expansion
- showed excessive time spent in producer_is_gxx_lt_4_6. */
+ /* These cache the results for producer_is_* fields. CHECKED_PRODUCER is set
+ if all the producer_is_* fields are valid. This information is cached
+ because profiling CU expansion showed excessive time spent in
+ producer_is_gxx_lt_4_6. */
unsigned int checked_producer : 1;
unsigned int producer_is_gxx_lt_4_6 : 1;
+ unsigned int producer_is_gcc_lt_4_3 : 1;
unsigned int producer_is_icc : 1;
};
@@ -1710,6 +1711,8 @@ static void free_dwo_file_cleanup (void *);
static void process_cu_includes (void);
+static void check_producer (struct dwarf2_cu *cu);
+
#if WORDS_BIGENDIAN
/* Convert VALUE between big- and little-endian. */
@@ -7803,6 +7806,19 @@ free_cu_line_header (void *arg)
cu->line_header = NULL;
}
+/* Check for possibly missing DW_AT_comp_dir with relative .debug_line
+ directory paths. GCC SVN r127613 (new option -fdebug-prefix-map) fixed
+ this, it was first present in GCC release 4.3.0. */
+
+static int
+producer_is_gcc_lt_4_3 (struct dwarf2_cu *cu)
+{
+ if (!cu->checked_producer)
+ check_producer (cu);
+
+ return cu->producer_is_gcc_lt_4_3;
+}
+
static void
find_file_and_directory (struct die_info *die, struct dwarf2_cu *cu,
char **name, char **comp_dir)
@@ -7823,7 +7839,8 @@ find_file_and_directory (struct die_info *die, struct dwarf2_cu *cu,
attr = dwarf2_attr (die, DW_AT_comp_dir, cu);
if (attr)
*comp_dir = DW_STRING (attr);
- else if (*name != NULL && IS_ABSOLUTE_PATH (*name))
+ else if (producer_is_gcc_lt_4_3 (cu) && *name != NULL
+ && IS_ABSOLUTE_PATH (*name))
{
*comp_dir = ldirname (*name);
if (*comp_dir != NULL)
@@ -10357,7 +10374,10 @@ check_producer (struct dwarf2_cu *cu)
/* Not recognized as GCC. */
}
else
- cu->producer_is_gxx_lt_4_6 = major < 4 || (major == 4 && minor < 6);
+ {
+ cu->producer_is_gxx_lt_4_6 = major < 4 || (major == 4 && minor < 6);
+ cu->producer_is_gcc_lt_4_3 = major < 4 || (major == 4 && minor < 3);
+ }
}
else if (strncmp (cu->producer, "Intel(R) C", strlen ("Intel(R) C")) == 0)
cu->producer_is_icc = 1;
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-compdir-oldgcc.S b/gdb/testsuite/gdb.dwarf2/dw2-compdir-oldgcc.S
new file mode 100644
index 0000000..8c1ed04
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-compdir-oldgcc.S
@@ -0,0 +1,230 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2012 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/>. */
+
+ .text
+main: .globl main
+
+gcc42: .globl gcc42
+ .int 0
+ .type gcc42, %function
+ .size gcc42, . - gcc42
+.Lgcc42_procend:
+
+gcc43: .globl gcc43
+ .int 0
+ .type gcc43, %function
+ .size gcc43, . - gcc43
+.Lgcc43_procend:
+
+/* Debug information */
+
+ .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 */
+
+ .uleb128 1 /* Abbrev: DW_TAG_compile_unit */
+ .4byte .Lgcc42_begin /* DW_AT_stmt_list */
+ .4byte gcc42 /* DW_AT_low_pc */
+ .4byte .Lgcc42_procend /* DW_AT_high_pc */
+ .ascii "/dir/d/dw2-compdir-oldgcc42.S\0" /* DW_AT_name */
+ .ascii "GNU C 4.2.0\0" /* DW_AT_producer */
+ .byte 1 /* DW_AT_language (C) */
+
+ .uleb128 2 /* Abbrev: DW_TAG_subprogram */
+ .byte 1 /* DW_AT_external */
+ .byte 1 /* DW_AT_decl_file */
+ .byte 1 /* DW_AT_decl_line */
+ .ascii "gcc42\0" /* DW_AT_name */
+ .4byte gcc42 /* DW_AT_low_pc */
+ .4byte .Lgcc42_procend /* DW_AT_high_pc */
+
+ .byte 0 /* End of children of CU */
+.Lcu1_end:
+
+.Lcu2_begin:
+ /* CU header */
+ .4byte .Lcu2_end - .Lcu2_start /* Length of Compilation Unit */
+.Lcu2_start:
+ .2byte 2 /* DWARF Version */
+ .4byte .Labbrev1_begin /* Offset into abbrev section */
+ .byte 4 /* Pointer size */
+
+ .uleb128 1 /* Abbrev: DW_TAG_compile_unit */
+ .4byte .Lgcc43_begin /* DW_AT_stmt_list */
+ .4byte gcc43 /* DW_AT_low_pc */
+ .4byte .Lgcc43_procend /* DW_AT_high_pc */
+ .ascii "/dir/d/dw2-compdir-oldgcc43.S\0" /* DW_AT_name */
+ .ascii "GNU C 4.3.0\0" /* DW_AT_producer */
+ .byte 1 /* DW_AT_language (C) */
+
+ .uleb128 2 /* Abbrev: DW_TAG_subprogram */
+ .byte 1 /* DW_AT_external */
+ .byte 1 /* DW_AT_decl_file */
+ .byte 1 /* DW_AT_decl_line */
+ .ascii "gcc43\0" /* DW_AT_name */
+ .4byte gcc43 /* DW_AT_low_pc */
+ .4byte .Lgcc43_procend /* DW_AT_high_pc */
+
+ .byte 0 /* End of children of CU */
+.Lcu2_end:
+
+/* Abbrev table */
+ .section .debug_abbrev
+.Labbrev1_begin:
+ .uleb128 1 /* Abbrev code */
+ .uleb128 0x11 /* DW_TAG_compile_unit */
+ .byte 1 /* has_children */
+ .uleb128 0x10 /* DW_AT_stmt_list */
+ .uleb128 0x6 /* DW_FORM_data4 */
+ .uleb128 0x11 /* DW_AT_low_pc */
+ .uleb128 0x1 /* DW_FORM_addr */
+ .uleb128 0x12 /* DW_AT_high_pc */
+ .uleb128 0x1 /* DW_FORM_addr */
+ .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 0x2e /* DW_TAG_subprogram */
+ .byte 0 /* has_children */
+ .uleb128 0x3f /* DW_AT_external */
+ .uleb128 0xc /* DW_FORM_flag */
+ .uleb128 0x3a /* DW_AT_decl_file */
+ .uleb128 0xb /* DW_FORM_data1 */
+ .uleb128 0x3b /* DW_AT_decl_line */
+ .uleb128 0xb /* DW_FORM_data1 */
+ .uleb128 0x3 /* DW_AT_name */
+ .uleb128 0x8 /* DW_FORM_string */
+ .uleb128 0x11 /* DW_AT_low_pc */
+ .uleb128 0x1 /* DW_FORM_addr */
+ .uleb128 0x12 /* DW_AT_high_pc */
+ .uleb128 0x1 /* DW_FORM_addr */
+ .byte 0x0 /* Terminator */
+ .byte 0x0 /* Terminator */
+
+ .byte 0x0 /* Terminator */
+ .byte 0x0 /* Terminator */
+
+/* Line table */
+ .section .debug_line
+.Lgcc42_begin:
+ .4byte .Lgcc42_end - .Lgcc42_start /* Initial length */
+.Lgcc42_start:
+ .2byte 2 /* Version */
+ .4byte .Lgcc42_lines - .Lgcc42_hdr /* header_length */
+.Lgcc42_hdr:
+ .byte 1 /* Minimum insn length */
+ .byte 1 /* default_is_stmt */
+ .byte 1 /* line_base */
+ .byte 1 /* line_range */
+ .byte 4 /* opcode_base */
+
+ /* Standard lengths */
+ .byte 0
+ .byte 1
+ .byte 1
+
+ /* Include directories */
+ .byte 0
+
+ /* File names */
+ .ascii "dw2-compdir-oldgcc42.S\0"
+ .uleb128 0 /* directory */
+ .uleb128 0
+ .uleb128 0
+
+ .byte 0
+
+.Lgcc42_lines:
+ .byte 0 /* DW_LNE_set_address */
+ .uleb128 5
+ .byte 2
+ .4byte gcc42
+
+ .byte 3 /* DW_LNS_advance_line */
+ .sleb128 41 /* ... to 42 */
+
+ .byte 1 /* DW_LNS_copy */
+
+ .byte 0 /* DW_LNE_set_address */
+ .uleb128 5
+ .byte 2
+ .4byte .Lgcc42_procend
+
+ .byte 0 /* DW_LNE_end_of_sequence */
+ .uleb128 1
+ .byte 1
+.Lgcc42_end:
+
+.Lgcc43_begin:
+ .4byte .Lgcc43_end - .Lgcc43_start /* Initial length */
+.Lgcc43_start:
+ .2byte 2 /* Version */
+ .4byte .Lgcc43_lines - .Lgcc43_hdr /* header_length */
+.Lgcc43_hdr:
+ .byte 1 /* Minimum insn length */
+ .byte 1 /* default_is_stmt */
+ .byte 1 /* line_base */
+ .byte 1 /* line_range */
+ .byte 4 /* opcode_base */
+
+ /* Standard lengths */
+ .byte 0
+ .byte 1
+ .byte 1
+
+ /* Include directories */
+ .byte 0
+
+ /* File names */
+ .ascii "dw2-compdir-oldgcc43.S\0"
+ .uleb128 0 /* directory */
+ .uleb128 0
+ .uleb128 0
+
+ .byte 0
+
+.Lgcc43_lines:
+ .byte 0 /* DW_LNE_set_address */
+ .uleb128 5
+ .byte 2
+ .4byte gcc43
+
+ .byte 3 /* DW_LNS_advance_line */
+ .sleb128 42 /* ... to 43 */
+
+ .byte 1 /* DW_LNS_copy */
+
+ .byte 0 /* DW_LNE_set_address */
+ .uleb128 5
+ .byte 2
+ .4byte .Lgcc43_procend
+
+ .byte 0 /* DW_LNE_end_of_sequence */
+ .uleb128 1
+ .byte 1
+.Lgcc43_end:
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-compdir-oldgcc.exp b/gdb/testsuite/gdb.dwarf2/dw2-compdir-oldgcc.exp
new file mode 100644
index 0000000..c3c0209
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-compdir-oldgcc.exp
@@ -0,0 +1,42 @@
+# Copyright 2012 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
+}
+
+standard_testfile .S
+if {[prepare_for_testing $testfile.exp $testfile $srcfile]} {
+ return -1
+}
+
+# Here should be GDB-computed "Compilation directory is".
+gdb_test "list gcc42" ".*"
+gdb_test "info source" "\r\nCurrent source file is dw2-compdir-oldgcc42.S\r\nCompilation directory is /dir/d\r\n.*" \
+ "info source gcc42"
+
+# Here should not be GDB-computed "Compilation directory is".
+gdb_test "list gcc43" ".*"
+set test "info source gcc43"
+gdb_test_multiple "info source" $test {
+ -re "\r\nCompilation directory is .*\r\n$gdb_prompt $" {
+ fail $test
+ }
+ -re "\r\nCurrent source file is dw2-compdir-oldgcc43.S\r\n.*\r\n$gdb_prompt $" {
+ pass $test
+ }
+}