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* [binutils-gdb] Handle two-linetable function in find_epilogue_using_linetable
@ 2024-04-24 14:27 Bernd Edlinger
0 siblings, 0 replies; only message in thread
From: Bernd Edlinger @ 2024-04-24 14:27 UTC (permalink / raw)
To: gdb-cvs
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=730f5068f5fb6613e4faa2efc2309cd107562cbd
commit 730f5068f5fb6613e4faa2efc2309cd107562cbd
Author: Bernd Edlinger <bernd.edlinger@hotmail.de>
Date: Tue Apr 9 09:27:53 2024 +0000
Handle two-linetable function in find_epilogue_using_linetable
Consider the following test-case:
...
$ cat hello.c
int main()
{
printf("hello ");
#include "world.inc"
$ cat world.inc
printf("world\n");
return 0;
}
$ gcc -g hello.c
...
The line table for the compilation unit, consisting just of
function main, is translated into these two gdb line tables, one for hello.c
and one for world.inc:
...
compunit_symtab: hello.c
symtab: hello.c
INDEX LINE REL-ADDRESS UNREL-ADDRESS IS-STMT PROLOGUE-END EPILOGUE-BEGIN
0 3 0x400557 0x400557 Y
1 4 0x40055b 0x40055b Y
2 END 0x40056a 0x40056a Y
compunit_symtab: hello.c
symtab: world.inc
INDEX LINE REL-ADDRESS UNREL-ADDRESS IS-STMT PROLOGUE-END EPILOGUE-BEGIN
0 1 0x40056a 0x40056a Y
1 2 0x400574 0x400574 Y
2 3 0x400579 0x400579 Y
3 END 0x40057b 0x40057b Y
...
The epilogue of main starts at 0x400579:
...
400579: 5d pop %rbp
40057a: c3 ret
...
Now, say we have an epilogue_begin marker in the line table at 0x400579.
We won't find it using find_epilogue_using_linetable, because it does:
...
const struct symtab_and_line sal = find_pc_line (start_pc, 0);
...
which gets us the line table for hello.c.
Fix this by using "find_pc_line (end_pc - 1, 0)" instead.
Tested on x86_64-linux.
Co-Authored-By: Tom de Vries <tdevries@suse.de>
PR symtab/31622
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31622
Diff:
---
gdb/symtab.c | 11 +-
gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin-2.exp | 20 +++
gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.c.inc | 51 ++++++
gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp | 158 +---------------
.../gdb.dwarf2/dw2-epilogue-begin.exp.tcl | 199 +++++++++++++++++++++
gdb/testsuite/lib/dwarf.exp | 5 +-
6 files changed, 284 insertions(+), 160 deletions(-)
diff --git a/gdb/symtab.c b/gdb/symtab.c
index 06b32c03884..6d3732aee8c 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -4159,8 +4159,15 @@ find_epilogue_using_linetable (CORE_ADDR func_addr)
/* While the standard allows for multiple points marked with epilogue_begin
in the same function, for performance reasons, this function will only
- find the last address that sets this flag for a given block. */
- const struct symtab_and_line sal = find_pc_line (start_pc, 0);
+ find the last address that sets this flag for a given block.
+
+ The lines of a function can be described by several line tables in case
+ there are different files involved. There's a corner case where a
+ function epilogue is in a different file than a function start, and using
+ start_pc as argument to find_pc_line will mean we won't find the
+ epilogue. Instead, use "end_pc - 1" to maximize our chances of picking
+ the line table containing an epilogue. */
+ const struct symtab_and_line sal = find_pc_line (end_pc - 1, 0);
if (sal.symtab != nullptr && sal.symtab->language () != language_asm)
{
struct objfile *objfile = sal.symtab->compunit ()->objfile ();
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin-2.exp b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin-2.exp
new file mode 100644
index 00000000000..6302ef1ad05
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin-2.exp
@@ -0,0 +1,20 @@
+# Copyright 2022-2024 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/>.
+
+standard_testfile dw2-epilogue-begin.c dw2-epilogue-begin.S
+
+set version 2
+
+source $srcdir/$subdir/dw2-epilogue-begin.exp.tcl
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.c.inc b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.c.inc
new file mode 100644
index 00000000000..4ff445cf37d
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.c.inc
@@ -0,0 +1,51 @@
+/* Copyright 2023-2024 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/>. */
+
+void
+__attribute__((used))
+trivial (void)
+{
+ asm ("trivial_label: .global trivial_label"); /* trivial function */
+}
+
+char global;
+
+void
+watch (void)
+{ /* watch start */
+ asm ("watch_label: .global watch_label");
+ asm ("mov $0x0, %rax");
+ int local = 0; /* watch prologue */
+
+ asm ("watch_start: .global watch_start");
+ asm ("mov $0x1, %rax");
+ local = 1; /* watch assign */
+ asm ("watch_reassign: .global watch_reassign");
+ asm ("mov $0x2, %rax");
+ local = 2; /* watch reassign */
+ asm ("watch_end: .global watch_end"); /* watch end */
+}
+
+int
+main (void)
+{ /* main prologue */
+ asm ("main_label: .global main_label");
+ global = 0;
+ asm ("main_fun_call: .global main_fun_call");
+ watch (); /* main function call */
+ asm ("main_epilogue: .global main_epilogue");
+ global = 10;
+ return 0; /* main end */
+}
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp
index 7ae14fa9b5a..9b9d6c71de4 100644
--- a/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp
+++ b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp
@@ -13,162 +13,8 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
-# Check that GDB can honor the epilogue_begin flag the compiler can place
-# in the line-table data.
-# We test 2 things: 1. that a software watchpoint triggered in an epilogue
-# is correctly ignored
-# 2. that GDB can mark the same line as both prologue and epilogue
-
-load_lib dwarf.exp
-
-# This test can only be run on targets which support DWARF-2 and use gas.
-require dwarf2_support
-# restricted to x86 to make it simpler to follow a variable
-require is_x86_64_m64_target
-
standard_testfile .c .S
-set trivial_line [gdb_get_line_number "trivial function"]
-set main_prologue [gdb_get_line_number "main prologue"]
-set main_epilogue [gdb_get_line_number "main end"]
-set watch_start_line [gdb_get_line_number "watch start"]
-
-set asm_file [standard_output_file $srcfile2]
-
-# The producer will be set to clang because at the time of writing
-# we only care about epilogues if the producer is clang. When the
-# producer is GCC, variables use CFA locations, so watchpoints can
-# continue working even on epilogues.
-Dwarf::assemble $asm_file {
- global srcdir subdir srcfile srcfile2
- global trivial_line main_prologue main_epilogue watch_start_line
- declare_labels lines_label
-
- get_func_info main
- get_func_info trivial
- get_func_info watch
-
- cu {} {
- compile_unit {
- {language @DW_LANG_C}
- {name dw2-prologue-end.c}
- {stmt_list ${lines_label} DW_FORM_sec_offset}
- {producer "clang version 17.0.1"}
- } {
- declare_labels char_label
-
- char_label: base_type {
- {name char}
- {encoding @DW_ATE_signed}
- {byte_size 1 DW_FORM_sdata}
- }
-
- subprogram {
- {external 1 flag}
- {name trivial}
- {low_pc $trivial_start addr}
- {high_pc "$trivial_start + $trivial_len" addr}
- }
- subprogram {
- {external 1 flag}
- {name watch}
- {low_pc $watch_start addr}
- {high_pc "$watch_start + $watch_len" addr}
- } {
- DW_TAG_variable {
- {name local}
- {type :$char_label}
- {DW_AT_location {DW_OP_reg0} SPECIAL_expr}
- }
- }
- subprogram {
- {external 1 flag}
- {name main}
- {low_pc $main_start addr}
- {high_pc "$main_start + $main_len" addr}
- }
- }
- }
-
- lines {version 5} lines_label {
- set diridx [include_dir "${srcdir}/${subdir}"]
- file_name "$srcfile" $diridx
-
- program {
- DW_LNS_set_file $diridx
- DW_LNE_set_address $trivial_start
- line $trivial_line
- DW_LNS_set_prologue_end
- DW_LNS_set_epilogue_begin
- DW_LNS_copy
-
- DW_LNE_set_address watch
- line $watch_start_line
- DW_LNS_copy
-
- DW_LNE_set_address watch_start
- line [gdb_get_line_number "watch assign"]
- DW_LNS_set_prologue_end
- DW_LNS_copy
-
- DW_LNE_set_address watch_reassign
- line [gdb_get_line_number "watch reassign"]
- DW_LNS_set_epilogue_begin
- DW_LNS_copy
-
- DW_LNE_set_address watch_end
- line [gdb_get_line_number "watch end"]
- DW_LNS_copy
-
- DW_LNE_set_address $main_start
- line $main_prologue
- DW_LNS_set_prologue_end
- DW_LNS_copy
-
- DW_LNE_set_address main_fun_call
- line [gdb_get_line_number "main function call"]
- DW_LNS_copy
-
- DW_LNE_set_address main_epilogue
- line $main_epilogue
- DW_LNS_set_epilogue_begin
- DW_LNS_copy
-
- DW_LNE_set_address "$main_start + $main_len"
- DW_LNE_end_sequence
- }
- }
-}
-
-if { [prepare_for_testing "failed to prepare" ${testfile} \
- [list $srcfile $asm_file] {nodebug}] } {
- return -1
-}
-
-if ![runto_main] {
- return -1
-}
-
-# Moving to the scope with a local variable.
-gdb_breakpoint $watch_start_line
-gdb_continue_to_breakpoint "continuing to function" ".*"
-gdb_test "next" "local = 2.*" "stepping to epilogue"
-
-# Forcing software watchpoints because hardware ones don't care if we
-# are in the epilogue or not.
-gdb_test_no_output "set can-use-hw-watchpoints 0"
-
-# Test that the software watchpoint will not trigger in this case
-gdb_test "watch local" "\[W|w\]atchpoint .: local" "set watchpoint"
-gdb_test "continue" ".*\[W|w\]atchpoint . deleted.*" \
- "confirm watchpoint doesn't trigger"
+set version 1
-# First we test that the trivial function has a line with both a prologue
-# and an epilogue. Do this by finding a line that has 3 Y columns
-set sep "\[ \t\]"
-set hex_number "0x\[0-9a-f\]+"
-gdb_test_multiple "maint info line-table" "test epilogue in linetable" -lbl {
- -re "\[0-9\]$sep+$trivial_line$sep+$hex_number$sep+$hex_number$sep+Y$sep+Y$sep+Y" {
- pass $gdb_test_name
- }
-}
+source $srcdir/$subdir/dw2-epilogue-begin.exp.tcl
diff --git a/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp.tcl b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp.tcl
new file mode 100644
index 00000000000..155916b92df
--- /dev/null
+++ b/gdb/testsuite/gdb.dwarf2/dw2-epilogue-begin.exp.tcl
@@ -0,0 +1,199 @@
+# Copyright 2022-2024 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/>.
+
+# Check that GDB can honor the epilogue_begin flag the compiler can place
+# in the line-table data.
+# We test 2 things: 1. that a software watchpoint triggered in an epilogue
+# is correctly ignored
+# 2. that GDB can mark the same line as both prologue and epilogue
+
+load_lib dwarf.exp
+
+# This test can only be run on targets which support DWARF-2 and use gas.
+require dwarf2_support
+# restricted to x86 to make it simpler to follow a variable
+require is_x86_64_m64_target
+
+set trivial_line [gdb_get_line_number "trivial function"]
+set main_prologue [gdb_get_line_number "main prologue"]
+set main_epilogue [gdb_get_line_number "main end"]
+set watch_start_line [gdb_get_line_number "watch start"]
+
+set asm_file [standard_output_file $srcfile2]
+
+# The producer will be set to clang because at the time of writing
+# we only care about epilogues if the producer is clang. When the
+# producer is GCC, variables use CFA locations, so watchpoints can
+# continue working even on epilogues.
+Dwarf::assemble $asm_file {
+ global srcdir subdir srcfile srcfile2
+ global trivial_line main_prologue main_epilogue watch_start_line
+ declare_labels lines_label
+
+ get_func_info main
+ get_func_info trivial
+ get_func_info watch
+
+ if { $::version == 1 } {
+ set switch_file {}
+ } elseif { $::version == 2 } {
+ set switch_file { set f $f2 }
+ } else {
+ error "Unhandled version: $::version"
+ }
+
+ cu {} {
+ compile_unit {
+ {language @DW_LANG_C}
+ {name dw2-prologue-end.c}
+ {stmt_list ${lines_label} DW_FORM_sec_offset}
+ {producer "clang version 17.0.1"}
+ } {
+ declare_labels char_label
+
+ char_label: base_type {
+ {name char}
+ {encoding @DW_ATE_signed}
+ {byte_size 1 DW_FORM_sdata}
+ }
+
+ subprogram {
+ {external 1 flag}
+ {name trivial}
+ {low_pc $trivial_start addr}
+ {high_pc "$trivial_start + $trivial_len" addr}
+ }
+ subprogram {
+ {external 1 flag}
+ {name watch}
+ {low_pc $watch_start addr}
+ {high_pc "$watch_start + $watch_len" addr}
+ } {
+ DW_TAG_variable {
+ {name local}
+ {type :$char_label}
+ {DW_AT_location {DW_OP_reg0} SPECIAL_expr}
+ }
+ }
+ subprogram {
+ {external 1 flag}
+ {name main}
+ {low_pc $main_start addr}
+ {high_pc "$main_start + $main_len" addr}
+ }
+ }
+ }
+
+ lines {version 5} lines_label {
+ set diridx [include_dir "${srcdir}/${subdir}"]
+ set f1 [file_name "$srcfile" $diridx]
+ set f2 [file_name "$srcfile.inc" $diridx]
+
+ set f $f1
+ program {
+ DW_LNS_set_file $f
+
+ DW_LNE_set_address $trivial_start
+ line $trivial_line
+ DW_LNS_set_prologue_end
+ DW_LNS_set_epilogue_begin
+ DW_LNS_copy
+
+ DW_LNE_set_address $trivial_end
+ DW_LNE_end_sequence
+
+
+ DW_LNS_set_file $f
+
+ DW_LNE_set_address $watch_start
+ line $watch_start_line
+ DW_LNS_copy
+
+ DW_LNE_set_address watch_start
+ line [gdb_get_line_number "watch assign"]
+ DW_LNS_set_prologue_end
+ DW_LNS_copy
+
+ eval $switch_file
+ DW_LNS_set_file $f
+
+ DW_LNE_set_address watch_reassign
+ line [gdb_get_line_number "watch reassign"]
+ DW_LNS_set_epilogue_begin
+ DW_LNS_copy
+
+ DW_LNE_set_address watch_end
+ line [gdb_get_line_number "watch end"]
+ DW_LNS_copy
+
+ DW_LNE_set_address $watch_end
+ DW_LNE_end_sequence
+
+
+ DW_LNS_set_file $f
+
+ DW_LNE_set_address $main_start
+ line $main_prologue
+ DW_LNS_set_prologue_end
+ DW_LNS_copy
+
+ DW_LNE_set_address main_fun_call
+ line [gdb_get_line_number "main function call"]
+ DW_LNS_copy
+
+ DW_LNE_set_address main_epilogue
+ line $main_epilogue
+ DW_LNS_set_epilogue_begin
+ DW_LNS_copy
+
+ DW_LNE_set_address $main_end
+ DW_LNE_end_sequence
+ }
+ }
+}
+
+if { [prepare_for_testing "failed to prepare" ${testfile} \
+ [list $srcfile $asm_file] {nodebug}] } {
+ return -1
+}
+
+if ![runto_main] {
+ return -1
+}
+
+# Moving to the scope with a local variable.
+
+gdb_breakpoint $srcfile:$watch_start_line
+gdb_continue_to_breakpoint "continuing to function" ".*"
+gdb_test "next" "local = 2.*" "stepping to epilogue"
+
+# Forcing software watchpoints because hardware ones don't care if we
+# are in the epilogue or not.
+gdb_test_no_output "set can-use-hw-watchpoints 0"
+
+# Test that the software watchpoint will not trigger in this case
+gdb_test "watch local" "\[W|w\]atchpoint .: local" "set watchpoint"
+gdb_test "continue" ".*\[W|w\]atchpoint . deleted.*" \
+ "confirm watchpoint doesn't trigger"
+
+# First we test that the trivial function has a line with both a prologue
+# and an epilogue. Do this by finding a line that has 3 Y columns
+set sep "\[ \t\]"
+set hex_number "0x\[0-9a-f\]+"
+gdb_test_multiple "maint info line-table" "test epilogue in linetable" -lbl {
+ -re "\[0-9\]$sep+$trivial_line$sep+$hex_number$sep+$hex_number$sep+Y$sep+Y$sep+Y" {
+ pass $gdb_test_name
+ }
+}
diff --git a/gdb/testsuite/lib/dwarf.exp b/gdb/testsuite/lib/dwarf.exp
index 1a97f83f8e6..44862dbb339 100644
--- a/gdb/testsuite/lib/dwarf.exp
+++ b/gdb/testsuite/lib/dwarf.exp
@@ -2427,10 +2427,11 @@ namespace eval Dwarf {
variable _line_file_names
lappend _line_file_names $filename $diridx
+ set nr_filenames [expr [llength $_line_file_names] / 2]
if { $Dwarf::_line_unit_version >= 5 } {
- return [expr [llength $_line_file_names] - 1]
+ return [expr $nr_filenames - 1]
} else {
- return [llength $_line_file_names]
+ return $nr_filenames
}
}
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