[PATCH v2 2/2] Aarch64: Fix segfault when casting dummy calls

Alan Hayward
2018-10-01T15:53:19Z

Prevent the following int cast causing a segfault on aarch64:
(gdb) b foo if (int)strcmp(name,"abc") == 0
(gdb) run

Instead of incorrectly re-calculating lang_struct_return, reuse
the version passed in.

Add common test case using a shared library to ensure FUNC resolving.

gdb/ChangeLog:

2018-10-01 Alan Hayward <alan.hayward@arm.com>

PR gdb/22736:
* aarch64-tdep.c (aarch64_push_dummy_call): Reuse
lang_struct_return.

gdb/testsuite/ChangeLog:

2018-10-01 Alan Hayward <alan.hayward@arm.com>

PR gdb/22736:
* gdb.base/condbreak-solib-lib.cc: New test.
* gdb.base/condbreak-solib-main.cc: New test.
* gdb.base/condbreak-solib.exp: New file.
---
gdb/aarch64-tdep.c | 27 +-----
gdb/testsuite/gdb.base/condbreak-solib-lib.cc | 21 +++++
.../gdb.base/condbreak-solib-main.cc | 33 +++++++
gdb/testsuite/gdb.base/condbreak-solib.exp | 93 +++++++++++++++++++
4 files changed, 149 insertions(+), 25 deletions(-)
create mode 100644 gdb/testsuite/gdb.base/condbreak-solib-lib.cc
create mode 100644 gdb/testsuite/gdb.base/condbreak-solib-main.cc
create mode 100644 gdb/testsuite/gdb.base/condbreak-solib.exp

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 504b040c2e..f6eabc7029 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -1513,14 +1513,11 @@ static CORE_ADDR
aarch64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
struct regcache *regcache, CORE_ADDR bp_addr,
int nargs, struct value **args, CORE_ADDR sp,
- int struct_return, int lang_struct_return_unused,
+ int struct_return, int lang_struct_return,
CORE_ADDR struct_addr)
{
int argnum;
struct aarch64_call_info info;
- struct type *func_type;
- struct type *return_type;
- int lang_struct_return;

memset (&info, 0, sizeof (info));

@@ -1542,27 +1539,7 @@ aarch64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
If the language code decides to pass in memory we want to move
the pointer inserted as the initial argument from the argument
list and into X8, the conventional AArch64 struct return pointer
- register.
-
- This is slightly awkward, ideally the flag "lang_struct_return"
- would be passed to the targets implementation of push_dummy_call.
- Rather that change the target interface we call the language code
- directly ourselves. */
-
- func_type = check_typedef (value_type (function));
-
- /* Dereference function pointer types. */
- if (TYPE_CODE (func_type) == TYPE_CODE_PTR)
- func_type = TYPE_TARGET_TYPE (func_type);
-
- gdb_assert (TYPE_CODE (func_type) == TYPE_CODE_FUNC
- || TYPE_CODE (func_type) == TYPE_CODE_METHOD);
-
- /* If language_pass_by_reference () returned true we will have been
- given an additional initial argument, a hidden pointer to the
- return slot in memory. */
- return_type = TYPE_TARGET_TYPE (func_type);
- lang_struct_return = language_pass_by_reference (return_type);
+ register. */

/* Set the return address. For the AArch64, the return breakpoint
is always at BP_ADDR. */
diff --git a/gdb/testsuite/gdb.base/condbreak-solib-lib.cc b/gdb/testsuite/gdb.base/condbreak-solib-lib.cc
new file mode 100644
index 0000000000..02bf450c43
--- /dev/null
+++ b/gdb/testsuite/gdb.base/condbreak-solib-lib.cc
@@ -0,0 +1,21 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2018 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/>. */
+
+int cmp3 (char *name)
+{
+ return name[0] == '3';
+}
diff --git a/gdb/testsuite/gdb.base/condbreak-solib-main.cc b/gdb/testsuite/gdb.base/condbreak-solib-main.cc
new file mode 100644
index 0000000000..43d39d1da4
--- /dev/null
+++ b/gdb/testsuite/gdb.base/condbreak-solib-main.cc
@@ -0,0 +1,33 @@
+/* This testcase is part of GDB, the GNU debugger.
+
+ Copyright 2018 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 cmp3 (char *name);
+
+const char *word = "stuff";
+
+int bar ()
+{
+ return 1;
+}
+
+int main (void)
+{
+ cmp3 ((char*)"a");
+ bar ();
+ cmp3 ((char*)"a");
+ bar ();
+}
diff --git a/gdb/testsuite/gdb.base/condbreak-solib.exp b/gdb/testsuite/gdb.base/condbreak-solib.exp
new file mode 100644
index 0000000000..27639bd109
--- /dev/null
+++ b/gdb/testsuite/gdb.base/condbreak-solib.exp
@@ -0,0 +1,93 @@
+# This testcase is part of GDB, the GNU debugger.
+# Copyright 2018 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 conditional breakpoints on functions in shared libraries.
+
+if { [skip_cplus_tests] } { continue }
+
+if {![is_elf_target]} {
+ return 0
+}
+
+if [skip_shlib_tests] {
+ return 0
+}
+
+set target_size TARGET_UNKNOWN
+if {[is_lp64_target]} {
+ set target_size TARGET_LP64
+} elseif {[is_ilp32_target]} {
+ set target_size TARGET_ILP32
+} else {
+ return 0
+}
+
+set main_basename condbreak-solib-main
+set lib_basename condbreak-solib-lib
+
+standard_testfile $main_basename.cc $lib_basename.cc
+
+if [get_compiler_info "c++"] {
+ return -1
+}
+
+set libsrc "${srcdir}/${subdir}/${srcfile2}"
+set lib_so [standard_output_file ${lib_basename}.so]
+set lib_syms [shlib_symbol_file ${lib_so}]
+set lib_dlopen [shlib_target_file ${lib_basename}.so]
+
+
+if [get_compiler_info] {
+ return -1
+}
+
+# Compile a shared library containing cmp3
+
+if {[gdb_compile_shlib $libsrc $lib_so {debug c++}] != ""} {
+ untested "failed to compile shared library"
+ return
+}
+
+# Compile the main test linked against the shared library
+
+set exec_opts [list debug c++ "additional_flags= -I$srcdir/../../include/ -D$target_size\
+ -DSHLIB_NAME\\=\"$lib_dlopen\""]
+
+if {[prepare_for_testing "failed to prepare" $binfile "$srcfile $srcfile2" $exec_opts]} {
+ return
+}
+
+gdb_load_shlib ${lib_so}
+
+if ![runto_main] then {
+ fail "can't run to main"
+ return
+}
+
+# Create conditional breakpoint on cmp3(), which will fail the condition.
+
+gdb_test "b cmp3 if (int)strcmp(word,\"abc\") == 0" "Breakpoint .*"
+
+gdb_test "b bar" "Breakpoint .*"
+
+gdb_test "c" "Breakpoint .* bar .*"
+
+# Create conditional breakpoint on cmp3(), which will pass the condition.
+
+gdb_test "b cmp3 if (int)strcmp(word,\"stuff\") == 0" "Breakpoint .*"
+
+gdb_test "c" "Breakpoint .* cmp3 .*"
+
--
2.17.1 (Apple Git-112)