[PR,gdb/16841] virtual inheritance via typedef cannot find base

Message ID 1529106313-11806-1-git-send-email-weimin.pan@oracle.com
State New, archived
Headers

Commit Message

Weimin Pan June 15, 2018, 11:45 p.m. UTC
  Fix failure to find member of a typedef base class

The test case below demonstrates the problem, as described in this PR's Comment 5:

typedef struct {
        int x;
} A;

struct C : A {
        int y;
};

int main()
{
        C c;
        return 55;
}

$ gdb a.out
(gdb) ptype C::x
Internal error: non-aggregate type to value_struct_elt_for_reference

In value_struct_elt_for_reference(), need to call check_typedef() on
the aggregate type to handle the case of *curtype being ptr->typedef.

Tested on x86_64-linux. No regressions.
---
 gdb/ChangeLog                               |  6 +++++
 gdb/testsuite/ChangeLog                     |  6 +++++
 gdb/testsuite/gdb.cp/typedef-base-ptype.cc  | 30 +++++++++++++++++++++++
 gdb/testsuite/gdb.cp/typedef-base-ptype.exp | 37 +++++++++++++++++++++++++++++
 gdb/valops.c                                |  2 +-
 5 files changed, 80 insertions(+), 1 deletion(-)
 create mode 100644 gdb/testsuite/gdb.cp/typedef-base-ptype.cc
 create mode 100644 gdb/testsuite/gdb.cp/typedef-base-ptype.exp
  

Comments

Simon Marchi June 17, 2018, 1:06 a.m. UTC | #1
On 2018-06-15 07:45 PM, Weimin Pan wrote:
> Fix failure to find member of a typedef base class
> 
> The test case below demonstrates the problem, as described in this PR's Comment 5:
> 
> typedef struct {
>         int x;
> } A;
> 
> struct C : A {
>         int y;
> };
> 
> int main()
> {
>         C c;
>         return 55;
> }
> 
> $ gdb a.out
> (gdb) ptype C::x
> Internal error: non-aggregate type to value_struct_elt_for_reference
> 
> In value_struct_elt_for_reference(), need to call check_typedef() on
> the aggregate type to handle the case of *curtype being ptr->typedef.

Thanks, that makes sense.  I noted some nits, you can push the patch after
addressing them.

> diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
> index b2938b1..78771d3 100644
> --- a/gdb/testsuite/ChangeLog
> +++ b/gdb/testsuite/ChangeLog
> @@ -1,3 +1,9 @@
> +2018-06-12  Weimin Pan  <weimin.pan@oracle.com>
> +
> +	PR gdb/16841
> +	* gdb/testsuite/gdb.cp/typedef-base-ptype.cc: New file.
> +	* gdb/testsuite/gdb.cp/typedef-base-ptype.exp: New file.

Filenames should be relative to the ChangeLog file, so remove "gdb/testsuite/".

> diff --git a/gdb/testsuite/gdb.cp/typedef-base-ptype.cc b/gdb/testsuite/gdb.cp/typedef-base-ptype.cc
> new file mode 100644
> index 0000000..bfbcc4a
> --- /dev/null
> +++ b/gdb/testsuite/gdb.cp/typedef-base-ptype.cc
> @@ -0,0 +1,30 @@
> +/* 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/>.  */
> +
> +typedef struct {
> +        int x;
> +} A;
> +
> +struct C : A {
> +        int y;
> +};
> +
> +int main()
> +{
> +        C c;
> +        return 55;
> +}

We try to make the test code follow the GNU coding style (unless testing
a particular formatting is the purpose of the test).

> diff --git a/gdb/testsuite/gdb.cp/typedef-base-ptype.exp b/gdb/testsuite/gdb.cp/typedef-base-ptype.exp

I would suggest naming this test "typedef-base.exp", because we may add other tests
than ptype in it.  For example, David's original reproducer in PR 16841 still won't
work after this patch (AFAIK), and would be a good candidate to end up as a test in
this file.

> new file mode 100644
> index 0000000..e588fd3
> --- /dev/null
> +++ b/gdb/testsuite/gdb.cp/typedef-base-ptype.exp
> @@ -0,0 +1,37 @@
> +# 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/>.

Can you add a one-liner comment that states the purpose of the test?  Something
like

  # Make sure that inheritance through a typedef is well handled.

Thanks,

Simon
  
Weimin Pan June 18, 2018, 4:12 p.m. UTC | #2
On 6/16/2018 6:06 PM, Simon Marchi wrote:
> On 2018-06-15 07:45 PM, Weimin Pan wrote:
>> Fix failure to find member of a typedef base class
>>
>> The test case below demonstrates the problem, as described in this PR's Comment 5:
>>
>> typedef struct {
>>          int x;
>> } A;
>>
>> struct C : A {
>>          int y;
>> };
>>
>> int main()
>> {
>>          C c;
>>          return 55;
>> }
>>
>> $ gdb a.out
>> (gdb) ptype C::x
>> Internal error: non-aggregate type to value_struct_elt_for_reference
>>
>> In value_struct_elt_for_reference(), need to call check_typedef() on
>> the aggregate type to handle the case of *curtype being ptr->typedef.
> Thanks, that makes sense.  I noted some nits, you can push the patch after
> addressing them.
>
>> diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
>> index b2938b1..78771d3 100644
>> --- a/gdb/testsuite/ChangeLog
>> +++ b/gdb/testsuite/ChangeLog
>> @@ -1,3 +1,9 @@
>> +2018-06-12  Weimin Pan  <weimin.pan@oracle.com>
>> +
>> +	PR gdb/16841
>> +	* gdb/testsuite/gdb.cp/typedef-base-ptype.cc: New file.
>> +	* gdb/testsuite/gdb.cp/typedef-base-ptype.exp: New file.
> Filenames should be relative to the ChangeLog file, so remove "gdb/testsuite/".
>
>> diff --git a/gdb/testsuite/gdb.cp/typedef-base-ptype.cc b/gdb/testsuite/gdb.cp/typedef-base-ptype.cc
>> new file mode 100644
>> index 0000000..bfbcc4a
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.cp/typedef-base-ptype.cc
>> @@ -0,0 +1,30 @@
>> +/* 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/>.  */
>> +
>> +typedef struct {
>> +        int x;
>> +} A;
>> +
>> +struct C : A {
>> +        int y;
>> +};
>> +
>> +int main()
>> +{
>> +        C c;
>> +        return 55;
>> +}
> We try to make the test code follow the GNU coding style (unless testing
> a particular formatting is the purpose of the test).
>
>> diff --git a/gdb/testsuite/gdb.cp/typedef-base-ptype.exp b/gdb/testsuite/gdb.cp/typedef-base-ptype.exp
> I would suggest naming this test "typedef-base.exp", because we may add other tests
> than ptype in it.  For example, David's original reproducer in PR 16841 still won't
> work after this patch (AFAIK), and would be a good candidate to end up as a test in
> this file.
>
>> new file mode 100644
>> index 0000000..e588fd3
>> --- /dev/null
>> +++ b/gdb/testsuite/gdb.cp/typedef-base-ptype.exp
>> @@ -0,0 +1,37 @@
>> +# 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/>.
> Can you add a one-liner comment that states the purpose of the test?  Something
> like
>
>    # Make sure that inheritance through a typedef is well handled.
>
> Thanks,
>
> Simon
>

Hi Simon,

Will incorporate your comments into the patch and push it.

Thanks,
Weimin
  

Patch

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index ff2f145..99a3175 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@ 
+2018-06-12  Weimin Pan  <weimin.pan@oracle.com>
+
+	PR gdb/16841
+	* valops.c (value_struct_elt_for_reference): Call check_typedef on 
+	aggregate type to get its real type before accessing it.
+
 2018-05-29  Weimin Pan  <weimin.pan@oracle.com>
 
 	* minsyms.h (lookup_minimal_symbol_and_objfile): Remove declaration.
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index b2938b1..78771d3 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@ 
+2018-06-12  Weimin Pan  <weimin.pan@oracle.com>
+
+	PR gdb/16841
+	* gdb/testsuite/gdb.cp/typedef-base-ptype.cc: New file.
+	* gdb/testsuite/gdb.cp/typedef-base-ptype.exp: New file.
+
 2018-05-24  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	PR gdb/23203
diff --git a/gdb/testsuite/gdb.cp/typedef-base-ptype.cc b/gdb/testsuite/gdb.cp/typedef-base-ptype.cc
new file mode 100644
index 0000000..bfbcc4a
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/typedef-base-ptype.cc
@@ -0,0 +1,30 @@ 
+/* 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/>.  */
+
+typedef struct {
+        int x;
+} A;
+
+struct C : A {
+        int y;
+};
+
+int main()
+{
+        C c;
+        return 55;
+}
diff --git a/gdb/testsuite/gdb.cp/typedef-base-ptype.exp b/gdb/testsuite/gdb.cp/typedef-base-ptype.exp
new file mode 100644
index 0000000..e588fd3
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/typedef-base-ptype.exp
@@ -0,0 +1,37 @@ 
+# 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/>.
+
+if { [skip_cplus_tests] } { continue }
+
+standard_testfile .cc
+
+if [get_compiler_info "c++"] {
+    return -1
+}
+
+if {[prepare_for_testing "failed to prepare" $testfile $srcfile {debug c++}]} {
+    return -1
+}
+
+clean_restart $testfile
+
+if ![runto_main] {
+    untested "could not run to main"
+    return -1
+}
+
+gdb_test "ptype C::x" \
+         "type = int" \
+         "ptype typedef base struct member"
diff --git a/gdb/valops.c b/gdb/valops.c
index 62a86c0..3970a25 100644
--- a/gdb/valops.c
+++ b/gdb/valops.c
@@ -3343,7 +3343,7 @@  value_struct_elt_for_reference (struct type *domain, int offset,
 				int want_address,
 				enum noside noside)
 {
-  struct type *t = curtype;
+  struct type *t = check_typedef (curtype);
   int i;
   struct value *v, *result;