[Bug c++/25955] New: FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[Bug c++/25955] New: FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

            Bug ID: 25955
           Summary: FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with
                    invalid regexp: run until breakpoint in main (unknown
                    output after running)
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: c++
          Assignee: unassigned at sourceware dot org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

When running test-case gdb.mi/mi-catch-cpp-exceptions.exp, I run into:
...
PASS: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: Setup
-catch-catch
-exec-continue^M
^running^M
*running,thread-id="all"^M
(gdb) ^M
=breakpoint-modified,bkpt={number="13",type="catchpoint",disp="keep",enabled="y",what="exception
throw",catch-type="throw",thread-groups=["i1"],regexp="blahblah",times="1"}^M
mi_expect_stop: expecting:
\*stopped,reason="breakpoint-hit",disp="keep",bkptno="[0-9]+",frame={addr="0x[0-9A-Fa-f]+",func="main",args=\[.*\],(?:file="[^
]*.*",fullname="(/[^\n]*/|\\\\[^\\]+\\[^\n]+\\|\\[^\\][^\n]*\\|[a-zA-Z]:[^\n]*\\).*",line="67",arch="[^
]*"|from=".*")}.*,thread-id="[0-9]+",stopped-threads=[^
]*^M
(=thread-selected,id="[0-9]+"^M
|=(?:breakpoint-created|breakpoint-deleted)[^
]+"^M
)*[(]gdb[)] ^M
$
~"\n"^M
~"Catchpoint 13 (exception thrown), 0x00007ffff7ab037e in __cxa_throw () from
/usr/lib64/libstdc++.so.6\n"^M
*stopped,bkptno="13",reason="breakpoint-hit",disp="keep",frame={addr="0x00007ffff7ab037e",func="__cxa_throw",args=[],from="/usr/lib64/libstdc++.so.6",arch="i386:x86-64"},thread-id="1",stopped-threads="all",core="0"^M
(gdb) ^M
got
=breakpoint-modified,bkpt={number="13",type="catchpoint",disp="keep",enabled="y",what="exception
throw",catch-type="throw",thread-groups=["i1"],regexp="blahblah",times="1"}^M
~"\n"^M
~"Catchpoint 13 (exception thrown), 0x00007ffff7ab037e in __cxa_throw () from
/usr/lib64/libstdc++.so.6\n"^M
*stopped,bkptno="13",reason="breakpoint-hit",disp="keep",frame={addr="0x00007ffff7ab037e",func="__cxa_throw",args=[],from="/usr/lib64/libstdc++.so.6",arch="i386:x86-64"},thread-id="1",stopped-threads="all",core="0"^M
(gdb) ^M

FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until
breakpoint in main (unknown output after running)
...

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[Bug c++/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |tromey at sourceware dot org

--- Comment #1 from Tom de Vries <vries at gcc dot gnu.org> ---
Bisects to:

commit 596dc4adfff347b4d8dc1f7e4eb57b8f2f342281 (HEAD, refs/bisect/bad)
Author: Tom Tromey <tom@tromey.com>
Date:   Fri May 8 14:14:05 2020 -0600

    Speed up psymbol reading by removing a copy

    I noticed that cp_canonicalize_string and friends copy a
    unique_xmalloc_ptr to a std::string.  However, this copy isn't
    genuinely needed anywhere, and it serves to slow down DWARF psymbol
    reading.

    This patch removes the copy and updates the callers to adapt.

    This speeds up the reader from 1.906 seconds (mean of 10 runs, of gdb
    on a copy of itself) to 1.888 seconds (mean of 10 runs, on the same
    copy as the first trial).

    gdb/ChangeLog
    2020-05-08  Tom Tromey  <tom@tromey.com>

            * symtab.h (class demangle_result_storage) <set_malloc_ptr>: New
            overload.
            <swap_string, m_string>: Remove.
            * symtab.c (demangle_for_lookup, completion_list_add_symbol):
            Update.

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[Bug c++/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

--- Comment #2 from Tom de Vries <vries at gcc dot gnu.org> ---
Before the offending commit, we have:
...
PASS: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: Setup
-catch-catch
-exec-continue
^running
*running,thread-id="all"
(gdb) 
mi_expect_stop: expecting:
\*stopped,reason="breakpoint-hit",disp="keep",bkptno="[0-9]+",frame={addr="0x[0-9A-Fa-f]+",func="main",args=\[.*\],(?:file="[^
]*.*",fullname="(/[^\n]*/|\\\\[^\\]+\\[^\n]+\\|\\[^\\][^\n]*\\|[a-zA-Z]:[^\n]*\\).*",line="67",arch="[^
]*"|from=".*")}.*,thread-id="[0-9]+",stopped-threads=[^
]*
(=thread-selected,id="[0-9]+"
|=(?:breakpoint-created|breakpoint-deleted)[^
]+"
)*[(]gdb[)] 
$
=breakpoint-modified,bkpt={number="12",type="breakpoint",disp="keep",enabled="y",addr="0x00000000004008e5",func="main()",file="/data/gdb_versions/devel/src/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.cc",fullname="/data/gdb_versions/devel/binutils-gdb.git/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.cc",line="67",thread-groups=["i1"],times="1",original-location="mi-catch-cpp-exceptions.cc:67"}
~"\n"
~"Breakpoint 12, main () at
/data/gdb_versions/devel/src/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.cc:67\n"
~"67\t\t    return 1;\t/* Stop here.  */\n"
*stopped,reason="breakpoint-hit",disp="keep",bkptno="12",frame={addr="0x00000000004008e5",func="main",args=[],file="/data/gdb_versions/devel/src/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.cc",fullname="/data/gdb_versions/devel/binutils-gdb.git/gdb/testsuite/gdb.mi/mi-catch-cpp-exceptions.cc",line="67",arch="i386:x86-64"},thread-id="1",stopped-threads="all",core="3"
(gdb) 
PASS: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until
breakpoint in main
...

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[Bug c++/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

--- Comment #3 from Tom de Vries <vries at gcc dot gnu.org> ---
Reproduce with command line:
...
$ gdb \
    -batch \
    ./outputs/gdb.mi/mi-catch-cpp-exceptions/mi-catch-cpp-exceptions \
    -ex "break 67" \
    -ex "catch throw -r blahblah" \
    -ex r
Breakpoint 1 at 0x4008e5: file mi-catch-cpp-exceptions.cc, line 67.
Catchpoint 2 (throw)

Catchpoint 2 (exception thrown), 0x00007ffff7ab037e in __cxa_throw () from
/usr/lib64/libstdc++.so.6
...

Before commit:
...
$ gdb \
    -batch \
    ./outputs/gdb.mi/mi-catch-cpp-exceptions/mi-catch-cpp-exceptions \
    -ex "break 67" \
    -ex "catch throw -r blahblah" \
    -ex r
Breakpoint 1 at 0x4008e5: file mi-catch-cpp-exceptions.cc, line 67.
Catchpoint 2 (throw)

Breakpoint 1, main () at mi-catch-cpp-exceptions.cc:67
67                  return 1;   /* Stop here.  */
...

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[Bug c++/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

--- Comment #4 from Tom de Vries <vries at gcc dot gnu.org> ---
Before the commit, we have in check_status_exception_catchpoint:
...
(gdb) n
150       std::string type_name;
(gdb) 
152       bkpt_breakpoint_ops.check_status (bs);
(gdb) 
153       if (bs->stop == 0)
(gdb) 
156       if (self->pattern == NULL)
(gdb) 
162           std::string canon;
(gdb) 
164           fetch_probe_arguments (NULL, &typeinfo_arg);
(gdb) 
165           type_name = cplus_typename_from_type_info (typeinfo_arg);
(gdb) 
167           canon = cp_canonicalize_string (type_name.c_str ());
(gdb) p type_name
$1 = "my_exception"
(gdb) n
168           if (!canon.empty ())
(gdb) p canon
$2 = ""
(gdb) n
162           std::string canon;
(gdb) 
176       if (!type_name.empty ())
(gdb) 
178           if (self->pattern->exec (type_name.c_str (), 0, NULL, 0) != 0)
(gdb) p type_name.c_str ()
$3 = 0x7fffffffce10 "my_exception"
...

And after the commit, we have:
...
(gdb) n
150       std::string type_name;
(gdb) 
152       bkpt_breakpoint_ops.check_status (bs);
(gdb) 
153       if (bs->stop == 0)
(gdb) 
156       if (self->pattern == NULL)
(gdb) 
159       const char *name = nullptr;
(gdb) 
160       gdb::unique_xmalloc_ptr<char> canon;
(gdb) 
165           fetch_probe_arguments (NULL, &typeinfo_arg);
(gdb) 
166           type_name = cplus_typename_from_type_info (typeinfo_arg);
(gdb) 
168           canon = cp_canonicalize_string (type_name.c_str ());
(gdb) p type_name
$1 = "my_exception"
(gdb) n
169           name = (canon == nullptr
(gdb) p canon
$2 = std::unique_ptr<char> = {get() = 0x0}
(gdb) n
170                   ? canon.get ()
(gdb) 
169           name = (canon == nullptr
(gdb) 
178       if (name != nullptr)
(gdb) p name
$3 = 0x0
(gdb) n
160       gdb::unique_xmalloc_ptr<char> canon;
(gdb) n
150       std::string type_name;
(gdb) n
183     }
...

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[Bug c++/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

--- Comment #5 from Tom de Vries <vries at gcc dot gnu.org> ---
Tentative patch:
...
diff --git a/gdb/break-catch-throw.c b/gdb/break-catch-throw.c
index 59293c4e57..7f4a9f955d 100644
--- a/gdb/break-catch-throw.c
+++ b/gdb/break-catch-throw.c
@@ -166,7 +166,7 @@ check_status_exception_catchpoint (struct bpstats *bs)
       type_name = cplus_typename_from_type_info (typeinfo_arg);

       canon = cp_canonicalize_string (type_name.c_str ());
-      name = (canon == nullptr
+      name = (canon != nullptr
              ? canon.get ()
              : type_name.c_str ());
     }
...

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[Bug gdb/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |gdb

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[Bug gdb/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

--- Comment #6 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tom de Vries <vries@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=4343499695830fbd4bfe75058fc5570e280ba831

commit 4343499695830fbd4bfe75058fc5570e280ba831
Author: Tom de Vries <tdevries@suse.de>
Date:   Sat May 9 20:17:10 2020 +0200

    [gdb] Fix catch throw regexp matching

    When running test-case gdb.mi/mi-catch-cpp-exceptions.exp, we have:
    ...
    FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run
until \
      breakpoint in main (unknown output after running)
    ...

    This is a regression since commit 596dc4adff "Speed up psymbol reading by
    removing a copy".

    Before that commit, we have:
    ...
    $ gdb \
        -batch \
        ./outputs/gdb.mi/mi-catch-cpp-exceptions/mi-catch-cpp-exceptions \
        -ex "break 67" \
        -ex "catch throw -r blahblah" \
        -ex r
    Breakpoint 1 at 0x4008e5: file mi-catch-cpp-exceptions.cc, line 67.
    Catchpoint 2 (throw)

    Breakpoint 1, main () at mi-catch-cpp-exceptions.cc:67
    67                  return 1;   /* Stop here.  */
    ...
    In other words:
    - we set a breakpoint somewhere in main,
    - we set a catchpoint with a regexp that is intended to not match any
      exception, and
    - run to the breakpoint, without the catchpoint triggering.

    After the commit, we have:
    ...
    $ gdb \
        -batch \
        ./outputs/gdb.mi/mi-catch-cpp-exceptions/mi-catch-cpp-exceptions \
        -ex "break 67" \
        -ex "catch throw -r blahblah" \
        -ex r
    Breakpoint 1 at 0x4008e5: file mi-catch-cpp-exceptions.cc, line 67.
    Catchpoint 2 (throw)

    Catchpoint 2 (exception thrown), 0x00007ffff7ab037e in __cxa_throw () from
\
      /usr/lib64/libstdc++.so.6
    ...
    In other words, the catchpoint triggers.

    This is caused by this bit of the commit:
    ...
           type_name = cplus_typename_from_type_info (typeinfo_arg);

           canon = cp_canonicalize_string (type_name.c_str ());
    -      if (!canon.empty ())
    -       std::swap (type_name, canon);
    +      name = (canon == nullptr
    +             ? canon.get ()
    +             : type_name.c_str ());
         }
       catch (const gdb_exception_error &e)
         {
           exception_print (gdb_stderr, e);
         }

    -  if (!type_name.empty ())
    +  if (name != nullptr)
         {
    -      if (self->pattern->exec (type_name.c_str (), 0, NULL, 0) != 0)
    +      if (self->pattern->exec (name, 0, NULL, 0) != 0)
    ...

    Before the commit, we have:
    - type_name == "my_exception"
    - canon = ""
    and the !type_name.empty () test succeeds, and gdb executes the
    self->pattern->exec call.

    After the commit, we have:
    - type_name == "my_exception"
    - canon == NULL
    - name == NULL
    and the name != nullptr test fails, and gdb doesn't execute the
    self->pattern->exec call.

    Fix this by inverting the condition for the calculation of name:
    ...
    -      name = (canon == nullptr
    +      name = (canon != nullptr
    ...

    Build and tested on x86_64-linux.

    gdb/ChangeLog:

    2020-05-09  Tom de Vries  <tdevries@suse.de>

            PR gdb/25955
            * break-catch-throw.c (check_status_exception_catchpoint): Fix name
            calculation.

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[Bug gdb/25955] FAIL: gdb.mi/mi-catch-cpp-exceptions.exp: all with invalid regexp: run until breakpoint in main (unknown output after running)

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=25955

Tom de Vries <vries at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED

--- Comment #7 from Tom de Vries <vries at gcc dot gnu.org> ---
Patch with fix committed, marking resolved-fixed.

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