From FEDORA_PATCHES Mon Sep 17 00:00:00 2001

From: Tom Tromey <tromey@adacore.com>

Date: Fri, 23 Apr 2021 11:28:48 -0600

Subject: gdb-gdb27743-psymtab-imported-unit.patch

;; Backport "Fix crash when expanding partial symtabs with DW_TAG_imported_unit"

;; (Tom Tromey, gdb/27743)

   From e7d77ce0c408e7019f9885b8be64c9cdb46dd312 Mon Sep 17 00:00:00 2001

   Subject: [PATCH] Fix crash when expanding partial symtabs with

 DW_TAG_imported_unit

PR gdb/27743 points out a gdb crash when expanding partial symtabs,

where one of the compilation units uses DW_TAG_imported_unit.

The bug is that partial_map_expand_apply expects only to be called for

the outermost psymtab.  However, filename searching doesn't (and

probably shouldn't) guarantee this.  The fix is to walk upward to find

the outermost CU.

A new test case is included.  It is mostly copied from other test

cases, which really sped up the effort.

This bug does not occur on trunk.  There,

psym_map_symtabs_matching_filename is gone, replaced by

psymbol_functions::expand_symtabs_matching.  When this find a match,

it calls psymtab_to_symtab, which does this same upward walk.

Tested on x86-64 Fedora 32.

I propose checking in this patch on the gdb-10 branch, and just the

new test case on trunk.

gdb/ChangeLog

2021-04-23  Tom Tromey  <tromey@adacore.com>

	PR gdb/27743:

	* psymtab.c (partial_map_expand_apply): Expand outermost psymtab.

gdb/testsuite/ChangeLog

2021-04-23  Tom Tromey  <tromey@adacore.com>

	PR gdb/27743:

	* gdb.dwarf2/imported-unit-bp.exp: New file.

	* gdb.dwarf2/imported-unit-bp-main.c: New file.

	* gdb.dwarf2/imported-unit-bp-alt.c: New file.

diff --git a/gdb/psymtab.c b/gdb/psymtab.c

--- a/gdb/psymtab.c

+++ b/gdb/psymtab.c

@@ -127,9 +127,10 @@ static struct compunit_symtab *psymtab_to_symtab (struct objfile *objfile,

 {

   struct compunit_symtab *last_made = objfile->compunit_symtabs;

-  /* Shared psymtabs should never be seen here.  Instead they should

-     be handled properly by the caller.  */

-  gdb_assert (pst->user == NULL);

+  /* We may see a shared psymtab here, but we want to expand the

+     outermost symtab.  */

+  while (pst->user != nullptr)

+    pst = pst->user;

   /* Don't visit already-expanded psymtabs.  */

   if (pst->readin_p (objfile))

diff --git a/gdb/testsuite/gdb.dwarf2/imported-unit-bp-alt.c b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-alt.c

new file mode 100644

--- /dev/null

+++ b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-alt.c

@@ -0,0 +1,50 @@

+/* Copyright 2020-2021 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/>.  */

+

+/* Used to insert labels with which we can build a fake line table.  */

+#define LL(N) asm ("line_label_" #N ": .globl line_label_" #N)

+

+volatile int var;

+volatile int bar;

+

+/* Generate some code to take up some space.  */

+#define FILLER do { \

+    var = 99;	    \

+} while (0)

+

+int

+func (void)

+{					/* func prologue */

+  asm ("func_label: .globl func_label");

+  LL (1);	// F1, Ln 16

+  FILLER;

+  LL (2);	// F1, Ln 17

+  FILLER;

+  LL (3);	// F2, Ln 21

+  FILLER;

+  LL (4);	// F2, Ln 22 // F1, Ln 18, !S

+  FILLER;

+  LL (5);	// F1, Ln 19 !S

+  FILLER;

+  LL (6);	// F1, Ln 20

+  FILLER;

+  LL (7);

+  FILLER;

+  return 0;				/* func end */

+}

+

+#ifdef WITHMAIN

+int main () { return 0; }

+#endif

diff --git a/gdb/testsuite/gdb.dwarf2/imported-unit-bp-main.c b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-main.c

new file mode 100644

--- /dev/null

+++ b/gdb/testsuite/gdb.dwarf2/imported-unit-bp-main.c

@@ -0,0 +1,24 @@

+/* This testcase is part of GDB, the GNU debugger.

+

+   Copyright 2004-2021 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/>.  */

+

+extern int func (void);

+

+int

+main()

+{

+  return func ();

+}

diff --git a/gdb/testsuite/gdb.dwarf2/imported-unit-bp.exp b/gdb/testsuite/gdb.dwarf2/imported-unit-bp.exp

new file mode 100644

--- /dev/null

+++ b/gdb/testsuite/gdb.dwarf2/imported-unit-bp.exp

@@ -0,0 +1,128 @@

+# Copyright 2020-2021 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 that "break /absolute/file:line" works ok with imported CUs.

+

+load_lib dwarf.exp

+

+# This test can only be run on targets which support DWARF-2 and use gas.

+if {![dwarf2_support]} {

+    return 0

+}

+

+# The .c files use __attribute__.

+if [get_compiler_info] {

+    return -1

+}

+if !$gcc_compiled {

+    return 0

+}

+

+standard_testfile imported-unit-bp-alt.c .S imported-unit-bp-main.c

+

+set build_options {nodebug optimize=-O1}

+

+set asm_file [standard_output_file $srcfile2]

+Dwarf::assemble $asm_file {

+    global srcdir subdir srcfile srcfile

+    global build_options

+    declare_labels lines_label callee_subprog_label cu_label

+

+    get_func_info func "$build_options additional_flags=-DWITHMAIN"

+

+    cu {} {

+	compile_unit {

+	    {language @DW_LANG_C}

+	    {name "<artificial>"}

+	} {

+	    imported_unit {

+		{import %$cu_label}

+	    }

+	}

+    }

+

+    cu {} {

+	cu_label: compile_unit {

+	    {producer "gcc"}

+	    {language @DW_LANG_C}

+	    {name ${srcfile}}

+	    {comp_dir "/tmp"}

+	    {low_pc 0 addr}

+	    {stmt_list ${lines_label} DW_FORM_sec_offset}

+	} {

+	    callee_subprog_label: subprogram {

+		{external 1 flag}

+		{name callee}

+		{inline 3 data1}

+	    }

+	    subprogram {

+		{external 1 flag}

+		{name func}

+		{low_pc $func_start addr}

+		{high_pc "$func_start + $func_len" addr}

+	    } {

+	    }

+	}

+    }

+

+    lines {version 2 default_is_stmt 1} lines_label {

+	include_dir "/tmp"

+	file_name "$srcfile" 1

+

+	program {

+	    {DW_LNE_set_address line_label_1}

+	    {DW_LNS_advance_line 15}

+	    {DW_LNS_copy}

+

+	    {DW_LNE_set_address line_label_2}

+	    {DW_LNS_advance_line 1}

+	    {DW_LNS_copy}

+

+	    {DW_LNE_set_address line_label_3}

+	    {DW_LNS_advance_line 4}

+	    {DW_LNS_copy}

+

+	    {DW_LNE_set_address line_label_4}

+	    {DW_LNS_advance_line 1}

+	    {DW_LNS_copy}

+

+	    {DW_LNS_advance_line -4}

+	    {DW_LNS_negate_stmt}

+	    {DW_LNS_copy}

+

+	    {DW_LNE_set_address line_label_5}

+	    {DW_LNS_advance_line 1}

+	    {DW_LNS_copy}

+

+	    {DW_LNE_set_address line_label_6}

+	    {DW_LNS_advance_line 1}

+	    {DW_LNS_negate_stmt}

+	    {DW_LNS_copy}

+

+	    {DW_LNE_set_address line_label_7}

+	    {DW_LNE_end_sequence}

+	}

+    }

+}

+

+if { [prepare_for_testing "failed to prepare" ${testfile} \

+	  [list $srcfile $asm_file $srcfile3] $build_options] } {

+    return -1

+}

+

+gdb_reinitialize_dir /tmp

+

+# Using an absolute path is important to see the bug.

+gdb_test "break /tmp/${srcfile}:19" "Breakpoint .* file $srcfile, line .*"