Fix crash with "finish" in Rust
Commit Message
PR rust/30090 points out that a certain "finish" in a Rust program
will cause gdb to crash. This happens due to some confusion about
field indices in rust_language::print_enum. The fix is to use
value_primitive_field so that the correct type can be passed; other
spots in rust-lang.c already do this.
Note that the enclosed test case comes with an xfail. This is needed
because for this function, rustc doesn't follow the platform ABI.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30090
---
gdb/rust-lang.c | 2 +-
gdb/testsuite/gdb.rust/finish.exp | 39 +++++++++++++++++++++++++++++++
gdb/testsuite/gdb.rust/finish.rs | 30 ++++++++++++++++++++++++
3 files changed, 70 insertions(+), 1 deletion(-)
create mode 100644 gdb/testsuite/gdb.rust/finish.exp
create mode 100644 gdb/testsuite/gdb.rust/finish.rs
Comments
>>>>> "Tom" == Tom Tromey <tom@tromey.com> writes:
Tom> PR rust/30090 points out that a certain "finish" in a Rust program
Tom> will cause gdb to crash. This happens due to some confusion about
Tom> field indices in rust_language::print_enum. The fix is to use
Tom> value_primitive_field so that the correct type can be passed; other
Tom> spots in rust-lang.c already do this.
Tom> Note that the enclosed test case comes with an xfail. This is needed
Tom> because for this function, rustc doesn't follow the platform ABI.
Tom> Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30090
I'm going to check this in now.
Tom
@@ -470,7 +470,7 @@ rust_language::print_enum (struct value *val, struct ui_file *stream,
}
int variant_fieldno = rust_enum_variant (type);
- val = value_field (val, variant_fieldno);
+ val = value_primitive_field (val, 0, variant_fieldno, type);
struct type *variant_type = type->field (variant_fieldno).type ();
int nfields = variant_type->num_fields ();
new file mode 100644
@@ -0,0 +1,39 @@
+# Copyright (C) 2023 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 a certain 'finish' in Rust.
+
+load_lib rust-support.exp
+require allow_rust_tests
+
+standard_testfile .rs
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug rust}]} {
+ return -1
+}
+
+set line [gdb_get_line_number "BREAK"]
+if {![runto ${srcfile}:$line]} {
+ untested "could not run to breakpoint"
+ return -1
+}
+
+# This 'finish' used to crash. See PR rust/30090. Also, this does
+# not currently print the correct value, because rustc does not use
+# the standard ABI here. This is being tracked here:
+# https://github.com/rust-lang/rust/issues/85641
+setup_xfail *-*-*
+gdb_test "finish" [string_to_regexp " = finish::MyResult::Some(97)"]
+gdb_test "next"
+gdb_test "print dei" [string_to_regexp " = finish::MyResult::Some(97)"]
new file mode 100644
@@ -0,0 +1,30 @@
+// Copyright (C) 2023 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/>.
+
+#![allow(warnings)]
+
+enum MyResult {
+ None,
+ Some(u32)
+}
+
+fn return_some() -> MyResult {
+ MyResult::Some(97) // BREAK
+}
+
+fn main() {
+ let dei = return_some();
+ let another = return_some();
+}