[PATCH v2] gdb: fix "frame function" issue when call is last instruction

[Sahil Siddiq <icegambit91@gmail.com>]

Currently, the "frame function" fails when the last
instruction is a call. In such a case, the $rip
register points to an address that lies outside the
frame.

Using "get_frame_address_in_block" instead of
"get_frame_pc" resolves this issue.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30929
---
Changes since v1:
* frame-selection-last-instr-call.exp: Modify test to fix regressions on arm/aarch64

Patch v1: https://sourceware.org/pipermail/gdb-patches/2024-June/210251.html

 gdb/stack.c                                   |   4 +-
 .../frame-selection-last-instr-call.c         |  28 ++++
 .../frame-selection-last-instr-call.exp       | 130 ++++++++++++++++++
 3 files changed, 160 insertions(+), 2 deletions(-)
 create mode 100644 gdb/testsuite/gdb.base/frame-selection-last-instr-call.c
 create mode 100644 gdb/testsuite/gdb.base/frame-selection-last-instr-call.exp

diff --git a/gdb/stack.c b/gdb/stack.c
index b36193be2f..8249866468 100644
--- a/gdb/stack.c
+++ b/gdb/stack.c
@@ -2860,8 +2860,8 @@ find_frame_for_function (const char *function_name)
   do
     {
       for (size_t i = 0; (i < sals.size () && !found); i++)
-	found = (get_frame_pc (frame) >= func_bounds[i].low
-		 && get_frame_pc (frame) < func_bounds[i].high);
+	found = (get_frame_address_in_block (frame) >= func_bounds[i].low
+		 && get_frame_address_in_block (frame) < func_bounds[i].high);
       if (!found)
 	{
 	  level = 1;
diff --git a/gdb/testsuite/gdb.base/frame-selection-last-instr-call.c b/gdb/testsuite/gdb.base/frame-selection-last-instr-call.c
new file mode 100644
index 0000000000..4f056332af
--- /dev/null
+++ b/gdb/testsuite/gdb.base/frame-selection-last-instr-call.c
@@ -0,0 +1,28 @@
+/* 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
+frame_1 (void)
+{
+  __builtin_abort();
+}
+
+int
+main (void)
+{
+  frame_1 ();
+}
diff --git a/gdb/testsuite/gdb.base/frame-selection-last-instr-call.exp b/gdb/testsuite/gdb.base/frame-selection-last-instr-call.exp
new file mode 100644
index 0000000000..5ba52cc069
--- /dev/null
+++ b/gdb/testsuite/gdb.base/frame-selection-last-instr-call.exp
@@ -0,0 +1,130 @@
+# 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/>.
+
+# This tests GDB's frame selection as used by the 'frame',
+# 'select-frame', and 'info frame' commands in the corner case
+# when the last instruction in a frame is a call.
+
+standard_testfile
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug}]} {
+    return -1
+}
+
+runto_main
+gdb_breakpoint abort
+gdb_continue_to_breakpoint abort
+
+gdb_test "bt" "#0  $hex in abort .*#1  $hex in frame_1 .*#2  $hex in main.*" "backtrace at breakpoint"
+
+# Perform "info frame" to extract the frame's address.
+proc get_frame_address { {testname ""} } {
+    global hex gdb_prompt
+
+    set frame_address "unknown"
+    set testname "get_frame_address: ${testname}"
+    gdb_test_multiple "info frame" $testname {
+	-re ", frame at ($hex):\r\n.*\r\n$gdb_prompt $" {
+	    set frame_address $expect_out(1,string)
+	    pass $testname
+	}
+    }
+
+    return $frame_address
+}
+
+# Check that the current frame is at stack depth LEVEL, at frame
+# address ADDRESS, and is in FUNCTION.
+proc check_frame { level address function } {
+    global hex gdb_prompt
+
+    set re [multi_line \
+		"Stack level ${level}, frame at ($address):" \
+		".* = $hex in ${function}( \(\[^\r\n\]*\))*; saved .* = $hex" \
+		".*\r\n$gdb_prompt $" ]
+
+    set testname "check frame level ${level}"
+    gdb_test_multiple "info frame" $testname {
+	-re $re {
+	    pass $testname
+	}
+    }
+}
+
+# Select frame using level, but relying on this being the default
+# action, so "frame 0" performs "frame level 0".
+gdb_test "frame 0" "#0  $hex in abort.*"
+set frame_0_address [ get_frame_address "frame 0" ]
+gdb_test "frame 1" "#1  $hex in frame_1.*"
+set frame_1_address [ get_frame_address "frame 1" ]
+gdb_test "frame 2" "#2  $hex in main.*"
+set frame_2_address [ get_frame_address "frame 2" ]
+
+# Select frame using 'level' specification.
+gdb_test "frame level 0" "#0  $hex in abort.*"
+gdb_test "frame level 1" "#1  $hex in frame_1.*"
+gdb_test "frame level 2" "#2  $hex in main.*"
+
+# Select frame by address.
+gdb_test "frame address ${frame_0_address}" "#0  $hex in abort.*" \
+    "select frame 0 by address"
+gdb_test "frame address ${frame_1_address}" "#1  $hex in frame_1.*" \
+    "select frame 1 by address"
+gdb_test "frame address ${frame_2_address}" "#2  $hex in main.*" \
+    "select frame 2 by address"
+
+# Select frame by function.
+gdb_test "frame function abort" "#0  $hex in abort.*"
+gdb_test "frame function frame_1" "#1  $hex in frame_1.*"
+gdb_test "frame function main" "#2  $hex in main.*"
+
+with_test_prefix "select-frame, no keyword" {
+    gdb_test_no_output "select-frame 0"
+    check_frame "0" "${frame_0_address}" "abort"
+    gdb_test_no_output "select-frame 1"
+    check_frame "1" "${frame_1_address}" "frame_1"
+    gdb_test_no_output "select-frame 2"
+    check_frame "2" "${frame_2_address}" "main"
+}
+
+with_test_prefix "select-frame, keyword=level" {
+    gdb_test_no_output "select-frame level 0"
+    check_frame "0" "${frame_0_address}" "abort"
+    gdb_test_no_output "select-frame level 1"
+    check_frame "1" "${frame_1_address}" "frame_1"
+    gdb_test_no_output "select-frame level 2"
+    check_frame "2" "${frame_2_address}" "main"
+}
+
+with_test_prefix "select-frame, keyword=address" {
+    gdb_test_no_output "select-frame address ${frame_0_address}" \
+	"select frame 0 by address"
+    check_frame "0" "${frame_0_address}" "abort"
+    gdb_test_no_output "select-frame address ${frame_1_address}" \
+	"select frame 1 by address"
+    check_frame "1" "${frame_1_address}" "frame_1"
+    gdb_test_no_output "select-frame address ${frame_2_address}" \
+	"select frame 2 by address"
+    check_frame "2" "${frame_2_address}" "main"
+}
+
+with_test_prefix "select-frame, keyword=function" {
+    gdb_test_no_output "select-frame function abort"
+    check_frame "0" "${frame_0_address}" "abort"
+    gdb_test_no_output "select-frame function frame_1"
+    check_frame "1" "${frame_1_address}" "frame_1"
+    gdb_test_no_output "select-frame function main"
+    check_frame "2" "${frame_2_address}" "main"
+}
-- 
2.45.2