File gdb-testsuite-fix-gdb.dwarf2-dw2-lines.exp-on-arm-li.patch of Package gdb
From e13b5af2c0bc0cdf1b2d66f184fff4ba019b28ec Mon Sep 17 00:00:00 2001
From: Tom de Vries <tdevries@suse.de>
Date: Wed, 4 Sep 2024 10:07:19 +0200
Subject: [PATCH 12/46] [gdb/testsuite] Fix gdb.dwarf2/dw2-lines.exp on
arm-linux
With test-case gdb.dwarf2/dw2-lines.exp on arm-linux, I run into:
...
(gdb) break bar_label^M
Breakpoint 2 at 0x4004f6: file dw2-lines.c, line 29.^M
(gdb) continue^M
Continuing.^M
^M
Breakpoint 2, bar () at dw2-lines.c:29^M
29 foo (2);^M
(gdb) PASS: $exp: cv=2: cdw=32: lv=2: ldw=32: continue to breakpoint: foo \(1\)
...
The pass is incorrect because the continue lands at line 29 with "foo (2)"
instead of line line 27 with "foo (1)".
A minimal version is:
...
$ gdb -q -batch dw2-lines.cv-2-cdw-32-lv-2-ldw-32 -ex "b bar_label"
Breakpoint 1 at 0x4f6: file dw2-lines.c, line 29.
...
where:
...
000004ec <bar>:
4ec: b580 push {r7, lr}
4ee: af00 add r7, sp, #0
000004f0 <bar_label>:
4f0: 2001 movs r0, #1
4f2: f7ff fff1 bl 4d8 <foo>
000004f6 <bar_label_2>:
4f6: 2002 movs r0, #2
4f8: f7ff ffee bl 4d8 <foo>
...
So, how does this happen? In short:
- skip_prologue_sal calls arm_skip_prologue with pc == 0x4ec,
- thumb_analyze_prologue returns 0x4f2
(overshooting by 1 insn, PR tdep/31981), and
- skip_prologue_sal decides that we're mid-line, and updates to 0x4f6.
However, this is a test-case about .debug_line info, so why didn't arm_skip_prologue
use the line info to skip the prologue?
The answer is that the line info starts at bar_label, not at bar.
Fixing that allows us to work around PR tdep/31981.
Likewise in gdb.dwarf2/dw2-line-number-zero.exp.
Instead, add a new test-case gdb.arch/skip-prologue.exp that is dedicated to
checking quality of architecture-specific prologue analysis, without being
written in an architecture-specific way.
If fails on arm-linux for both marm and mthumb:
...
FAIL: gdb.arch/skip-prologue.exp: f2: $bp_addr == $prologue_end_addr (skipped too much)
FAIL: gdb.arch/skip-prologue.exp: f4: $bp_addr == $prologue_end_addr (skipped too much)
...
and passes for:
- x86_64-linux for {m64,m32}x{-fno-PIE/-no-pie,-fPIE/-pie}
- aarch64-linux.
Tested on arm-linux.
---
gdb/testsuite/gdb.arch/skip-prologue.c | 54 +++++++++++++
gdb/testsuite/gdb.arch/skip-prologue.exp | 76 +++++++++++++++++++
.../gdb.dwarf2/dw2-line-number-zero.exp | 8 ++
gdb/testsuite/gdb.dwarf2/dw2-lines.c | 2 +-
gdb/testsuite/gdb.dwarf2/dw2-lines.exp | 4 +
5 files changed, 143 insertions(+), 1 deletion(-)
create mode 100644 gdb/testsuite/gdb.arch/skip-prologue.c
create mode 100644 gdb/testsuite/gdb.arch/skip-prologue.exp
diff --git a/gdb/testsuite/gdb.arch/skip-prologue.c b/gdb/testsuite/gdb.arch/skip-prologue.c
new file mode 100644
index 00000000000..08ceacb6aa8
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/skip-prologue.c
@@ -0,0 +1,54 @@
+/* Copyright 2024 Free Software Foundation, Inc.
+
+ This file is part of GDB.
+
+ 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/>. */
+
+void
+f1 (void)
+{
+ asm ("f1_prologue_end: .globl f1_prologue_end");
+}
+
+int
+f2 (int a)
+{
+ asm ("f2_prologue_end: .globl f2_prologue_end");
+ return a;
+}
+
+void
+f3 (void)
+{
+ asm ("f3_prologue_end: .globl f3_prologue_end");
+ f1 ();
+}
+
+int
+f4 (int a)
+{
+ asm ("f4_prologue_end: .globl f4_prologue_end");
+ return f2 (a);
+}
+
+int
+main (void)
+{
+ f1 ();
+ f2 (0);
+ f3 ();
+ f4 (0);
+
+ return 0;
+}
diff --git a/gdb/testsuite/gdb.arch/skip-prologue.exp b/gdb/testsuite/gdb.arch/skip-prologue.exp
new file mode 100644
index 00000000000..89d2225151a
--- /dev/null
+++ b/gdb/testsuite/gdb.arch/skip-prologue.exp
@@ -0,0 +1,76 @@
+# Copyright 2024 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/>.
+
+# Test-case that checks architecture-specific prologue analyzers.
+
+standard_testfile
+
+if { [prepare_for_testing "failed to prepare" $testfile $srcfile \
+ {nodebug}] } {
+ return -1
+}
+
+proc do_test { f } {
+ set bp_addr ""
+ gdb_test_multiple "break $f" "" {
+ -re -wrap "Breakpoint $::decimal at ($::hex)" {
+ set bp_addr $expect_out(1,string)
+ pass $gdb_test_name
+ }
+ }
+
+ if { $bp_addr == "" } {
+ return
+ }
+
+ set prologue_end_addr ""
+ gdb_test_multiple "p /x &${f}_prologue_end" "" {
+ -re -wrap " = ($::hex)" {
+ set prologue_end_addr $expect_out(1,string)
+ pass $gdb_test_name
+ }
+ }
+
+ if { $prologue_end_addr == "" } {
+ return
+ }
+
+ set test {$bp_addr == $prologue_end_addr}
+ if { [expr $test] } {
+ pass $test
+ } elseif { $bp_addr < $prologue_end_addr } {
+ # We'll allow this. For instance, amd64 has a prologue
+ # analyzer that doesn't skip the 3rd instruction here, which saves an
+ # argument register to stack:
+ #
+ # 00000000004004ae <f2>:
+ # 4004ae: 55 push %rbp
+ # 4004af: 48 89 e5 mov %rsp,%rbp
+ # 4004b2: 89 7d fc mov %edi,-0x4(%rbp)
+ # 00000000004004b5 <f2_prologue_end>:
+ #
+ pass "$test (skipped less than possible)"
+ } elseif { $bp_addr > $prologue_end_addr } {
+ fail "$test (skipped too much)"
+ } else {
+ fail "$test"
+ }
+}
+
+foreach f { f1 f2 f3 f4 } {
+ with_test_prefix $f {
+ do_test $f
+ }
+}
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp b/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp
index c510de42037..9124aff1dad 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-line-number-zero.exp
@@ -56,6 +56,10 @@ Dwarf::assemble $asm_file {
file_name "$srcfile" 1
program {
+ DW_LNE_set_address $bar1_start
+ line 25
+ DW_LNS_copy
+
DW_LNE_set_address bar1_label
line 27
DW_LNS_copy
@@ -76,6 +80,10 @@ Dwarf::assemble $asm_file {
DW_LNE_end_sequence
+ DW_LNE_set_address $bar2_start
+ line 39
+ DW_LNS_copy
+
DW_LNE_set_address bar2_label
line 41
DW_LNS_copy
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-lines.c b/gdb/testsuite/gdb.dwarf2/dw2-lines.c
index 67c98fecf02..221d7b95bc3 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-lines.c
+++ b/gdb/testsuite/gdb.dwarf2/dw2-lines.c
@@ -22,7 +22,7 @@ foo (int x)
void
bar (void)
-{
+{ /* bar: */
asm ("bar_label: .globl bar_label");
foo (1);
asm ("bar_label_2: .globl bar_label_2");
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-lines.exp b/gdb/testsuite/gdb.dwarf2/dw2-lines.exp
index af5b6b71768..fd5b83edc5b 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-lines.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-lines.exp
@@ -88,6 +88,10 @@ proc test_1 { _cv _cdw64 _lv _ldw64 {_string_form ""}} {
# to set the current file explicitly.
DW_LNS_set_file $diridx
+ DW_LNE_set_address $bar_start
+ line [line_for bar]
+ DW_LNS_copy
+
DW_LNE_set_address bar_label
line [line_for bar_label]
DW_LNS_copy
--
2.43.0
