Codebase list gdb / fe225fe
upstream proposed fix for PR/30158 Signed-off-by: Héctor Orón Martínez <zumbi@debian.org> Héctor Orón Martínez 1 year, 2 months ago
2 changed file(s) with 141 addition(s) and 0 deletion(s). Raw diff Collapse all Expand all
+140
-0
debian/patches/fix-crash-in-inside_main_func.patch less more
0 gdb 13.1 crashes while running the rust compiler's debugger tests.
1 The crash has a number of causes.
2
3 First, the rust compiler still uses the C++-like _Z mangling, but with
4 its own twist -- some hex digits added to the end of a symbol. So,
5 while gdb finds the correct name of "main":
6
7 (top-gdb) p name
8 $13 = 0x292e0c0 "rustc_gdb_1031745::main"
9
10 It isn't found in the minsyms, because C++ demangling yields:
11
12 [99] t 0x90c0 _ZN17rustc_gdb_10317454main17h5b5be7fe16a97225E section .text rustc_gdb_1031745::main::h5b5be7fe16a97225 zko06yobckx336v
13
14 This could perhaps be fixed. I also filed a new PR to suggest
15 preferring the linkage name of the main program.
16
17 Next, the rust compiler emits both a DW_TAG_subprogram and a
18 DW_TAG_namespace for "main". This happens because the file is named
19 "main.rs" -- i.e., the bug is specific to the source file name. The
20 crash also seems to require the nested function inside of 'main', at
21 least for me. The namespace always is generated, but perhaps this
22 changes the ordering in the DWARF.
23
24 When inside_main_func looks up the main symbol, it finds the namespace
25 symbol rather than the function. (I filed a bug about fixing gdb's
26 symbol tables -- long overdue.)
27
28 Meanwhile, as I think it's important to fix this crash sooner rather
29 than later, this patch changes inside_main_func to check that the
30 symbol that is found is LOC_BLOCK. This perhaps should have been done
31 in the first place, anyway.
32
33 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30158
34 ---
35 gdb/frame.c | 8 ++++++
36 gdb/testsuite/gdb.rust/main-crash.exp | 35 +++++++++++++++++++++++++++
37 gdb/testsuite/gdb.rust/main.rs | 30 +++++++++++++++++++++++
38 3 files changed, 73 insertions(+)
39 create mode 100644 gdb/testsuite/gdb.rust/main-crash.exp
40 create mode 100644 gdb/testsuite/gdb.rust/main.rs
41
42 diff --git a/gdb/frame.c b/gdb/frame.c
43 index 9b867b6cd9c..de3c7de440d 100644
44 --- a/gdb/frame.c
45 +++ b/gdb/frame.c
46 @@ -2551,6 +2551,14 @@ inside_main_func (frame_info_ptr this_frame)
47 if (bs.symbol == nullptr)
48 return false;
49
50 + /* We might have found some unrelated symbol. For example, the
51 + Rust compiler can emit both a subprogram and a namespace with
52 + the same name in the same scope; and due to how gdb's symbol
53 + tables currently work, we can't request the one we'd
54 + prefer. */
55 + if (bs.symbol->aclass () != LOC_BLOCK)
56 + return false;
57 +
58 const struct block *block = bs.symbol->value_block ();
59 gdb_assert (block != nullptr);
60 sym_addr = block->start ();
61 diff --git a/gdb/testsuite/gdb.rust/main-crash.exp b/gdb/testsuite/gdb.rust/main-crash.exp
62 new file mode 100644
63 index 00000000000..9c513f91c1d
64 --- /dev/null
65 +++ b/gdb/testsuite/gdb.rust/main-crash.exp
66 @@ -0,0 +1,35 @@
67 +# Copyright (C) 2023 Free Software Foundation, Inc.
68 +
69 +# This program is free software; you can redistribute it and/or modify
70 +# it under the terms of the GNU General Public License as published by
71 +# the Free Software Foundation; either version 3 of the License, or
72 +# (at your option) any later version.
73 +#
74 +# This program is distributed in the hope that it will be useful,
75 +# but WITHOUT ANY WARRANTY; without even the implied warranty of
76 +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
77 +# GNU General Public License for more details.
78 +#
79 +# You should have received a copy of the GNU General Public License
80 +# along with this program. If not, see <http://www.gnu.org/licenses/>.
81 +
82 +# Regression test for a crash in inside_main_func.
83 +
84 +load_lib rust-support.exp
85 +require allow_rust_tests
86 +
87 +standard_testfile main.rs
88 +if {[prepare_for_testing "failed to prepare" $testfile $srcfile \
89 + {debug rust}]} {
90 + return -1
91 +}
92 +
93 +set line [gdb_get_line_number "BREAK"]
94 +# The bug was that this would crash.
95 +if {![runto ${srcfile}:$line]} {
96 + untested "could not run to breakpoint"
97 + return -1
98 +}
99 +
100 +# Test that gdb is alive.
101 +gdb_test "print 23" " = 23"
102 diff --git a/gdb/testsuite/gdb.rust/main.rs b/gdb/testsuite/gdb.rust/main.rs
103 new file mode 100644
104 index 00000000000..8902446551e
105 --- /dev/null
106 +++ b/gdb/testsuite/gdb.rust/main.rs
107 @@ -0,0 +1,30 @@
108 +// Copyright (C) 2016-2023 Free Software Foundation, Inc.
109 +
110 +// This program is free software; you can redistribute it and/or modify
111 +// it under the terms of the GNU General Public License as published by
112 +// the Free Software Foundation; either version 3 of the License, or
113 +// (at your option) any later version.
114 +//
115 +// This program is distributed in the hope that it will be useful,
116 +// but WITHOUT ANY WARRANTY; without even the implied warranty of
117 +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
118 +// GNU General Public License for more details.
119 +//
120 +// You should have received a copy of the GNU General Public License
121 +// along with this program. If not, see <http://www.gnu.org/licenses/>.
122 +
123 +#![allow(dead_code)]
124 +#![allow(unused_variables)]
125 +#![allow(unused_assignments)]
126 +
127 +fn global_fn(x: u8) {
128 + // BREAK
129 +}
130 +
131 +fn main() {
132 + fn nested(y: u8) {
133 + global_fn(y)
134 + }
135 +
136 + nested(23);
137 +}
138 --
139 2.39.1
+1
-0
debian/patches/series less more
55 gdb_configure.nat.patch
66 fork-inferior-fix
77 fix-build.patch
8 fix-crash-in-inside_main_func.patch