diff mbox

PR c++/17494 - Fix evaluation of method calls under EVAL_SKIP

Message ID CAGyQ6gxnfw6yRmMzGG2T5acqO2od7WL7-8F1wVRTp9mfNvg9Sg@mail.gmail.com
State New
Headers show

Commit Message

Siva Chandra Reddy Oct. 20, 2014, 7:11 p.m. UTC
When evaluating method calls under EVAL_SKIP, the "object" and the
arguments to the method should also be evaluated under EVAL_SKIP,
instead of skipping to evaluate them. Getting this right fixes PR
c++/17494.

gdb/ChangeLog:

2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>

        PR c++/17494
        * eval.c (evaluate_subexp_standard): Evaluate the "object" and
        the method args also under EVAL_SKIP when evaluating method
        calls under EVAL_SKIP.

gdb/testsuite/ChangeLog:

2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>

        PR c++/17494
        * gdb.cp/pr17494.cc: New file.
        * gdb.cp/pr17494.exp: New file.

Comments

Siva Chandra Reddy Oct. 27, 2014, 5:22 p.m. UTC | #1
On Mon, Oct 20, 2014 at 12:11 PM, Siva Chandra <sivachandra@google.com> wrote:
> When evaluating method calls under EVAL_SKIP, the "object" and the
> arguments to the method should also be evaluated under EVAL_SKIP,
> instead of skipping to evaluate them. Getting this right fixes PR
> c++/17494.
>
> gdb/ChangeLog:
>
> 2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>
>
>         PR c++/17494
>         * eval.c (evaluate_subexp_standard): Evaluate the "object" and
>         the method args also under EVAL_SKIP when evaluating method
>         calls under EVAL_SKIP.
>
> gdb/testsuite/ChangeLog:
>
> 2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>
>
>         PR c++/17494
>         * gdb.cp/pr17494.cc: New file.
>         * gdb.cp/pr17494.exp: New file.

Ping.
Siva Chandra Reddy Nov. 3, 2014, 2:35 p.m. UTC | #2
On Mon, Oct 20, 2014 at 12:11 PM, Siva Chandra <sivachandra@google.com> wrote:
> When evaluating method calls under EVAL_SKIP, the "object" and the
> arguments to the method should also be evaluated under EVAL_SKIP,
> instead of skipping to evaluate them. Getting this right fixes PR
> c++/17494.
>
> gdb/ChangeLog:
>
> 2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>
>
>         PR c++/17494
>         * eval.c (evaluate_subexp_standard): Evaluate the "object" and
>         the method args also under EVAL_SKIP when evaluating method
>         calls under EVAL_SKIP.
>
> gdb/testsuite/ChangeLog:
>
> 2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>
>
>         PR c++/17494
>         * gdb.cp/pr17494.cc: New file.
>         * gdb.cp/pr17494.exp: New file.

Ping.
Siva Chandra Reddy Nov. 4, 2014, 2:08 a.m. UTC | #3
On Mon, Nov 3, 2014 at 7:08 AM, Ulrich Weigand <uweigand@de.ibm.com> wrote:
>>gdb/ChangeLog:
>>
>>2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>
>>
>>        PR c++/17494
>>        * eval.c (evaluate_subexp_standard): Evaluate the "object" and
>>        the method args also under EVAL_SKIP when evaluating method
>>        calls under EVAL_SKIP.
>>
>>gdb/testsuite/ChangeLog:
>>
>>2014-10-20  Siva Chandra Reddy  <sivachandra@google.com>
>>
>>        PR c++/17494
>>        * gdb.cp/pr17494.cc: New file.
>>        * gdb.cp/pr17494.exp: New file.
>
> This is OK.

Thanks for the review. Pushed: e0f52461c2467b6610391681fa27cd9b3c5def57
Alan Modra Nov. 5, 2014, 12:24 a.m. UTC | #4
On Mon, Nov 03, 2014 at 06:08:15PM -0800, Siva Chandra wrote:
> >>        PR c++/17494
> >>        * eval.c (evaluate_subexp_standard): Evaluate the "object" and
> >>        the method args also under EVAL_SKIP when evaluating method
> >>        calls under EVAL_SKIP.
> 
> Thanks for the review. Pushed: e0f52461c2467b6610391681fa27cd9b3c5def57

After this patch, when using gcc-4.9.1 and gcc-5.0 (20140911) I see
what looks to me to be nonsense errors (ie. I'd suspect a compiler
bug).  Does anyone else see the same?  Nothing special in configure
options, x86_64-linux.

/src/binutils-gdb/gdb/eval.c: In function ‘evaluate_subexp_standard’:
/src/binutils-gdb/gdb/eval.c:745:16: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
  struct value *ret = NULL;
                ^
In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
                 from /src/binutils-gdb/gdb/defs.h:28,
                 from /src/binutils-gdb/gdb/eval.c:20:
/src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
        SIGJMP_BUF *buf = \
                    ^
/src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
        SIGJMP_BUF *buf = \
                    ^
/src/binutils-gdb/gdb/eval.c:747:2: note: in expansion of macro ‘TRY_CATCH’
  TRY_CATCH (ex, RETURN_MASK_ERROR)
  ^
/src/binutils-gdb/gdb/eval.c:1429:19: error: ‘value’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
     struct value *value = NULL;
                   ^
In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
                 from /src/binutils-gdb/gdb/defs.h:28,
                 from /src/binutils-gdb/gdb/eval.c:20:
/src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
        SIGJMP_BUF *buf = \
                    ^
/src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
        SIGJMP_BUF *buf = \
                    ^
/src/binutils-gdb/gdb/eval.c:1430:5: note: in expansion of macro ‘TRY_CATCH’
     TRY_CATCH (except, RETURN_MASK_ERROR)
     ^
/src/binutils-gdb/gdb/eval.c:1846:18: error: ‘value’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
    struct value *value = NULL;
                  ^
In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
                 from /src/binutils-gdb/gdb/defs.h:28,
                 from /src/binutils-gdb/gdb/eval.c:20:
/src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
        SIGJMP_BUF *buf = \
                    ^
/src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
        SIGJMP_BUF *buf = \
                    ^
/src/binutils-gdb/gdb/eval.c:1847:4: note: in expansion of macro ‘TRY_CATCH’
    TRY_CATCH (except, RETURN_MASK_ERROR)
    ^
cc1: all warnings being treated as errors
Siva Chandra Reddy Nov. 5, 2014, 12:33 a.m. UTC | #5
Sorry if I am at fault. My compiler is gcc-4.8.2 and I do not see
these errors. I will dig further as soon as I can (which is not likely
until tomorrow).

On Tue, Nov 4, 2014 at 4:24 PM, Alan Modra <amodra@gmail.com> wrote:
> On Mon, Nov 03, 2014 at 06:08:15PM -0800, Siva Chandra wrote:
>> >>        PR c++/17494
>> >>        * eval.c (evaluate_subexp_standard): Evaluate the "object" and
>> >>        the method args also under EVAL_SKIP when evaluating method
>> >>        calls under EVAL_SKIP.
>>
>> Thanks for the review. Pushed: e0f52461c2467b6610391681fa27cd9b3c5def57
>
> After this patch, when using gcc-4.9.1 and gcc-5.0 (20140911) I see
> what looks to me to be nonsense errors (ie. I'd suspect a compiler
> bug).  Does anyone else see the same?  Nothing special in configure
> options, x86_64-linux.
>
> /src/binutils-gdb/gdb/eval.c: In function ‘evaluate_subexp_standard’:
> /src/binutils-gdb/gdb/eval.c:745:16: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>   struct value *ret = NULL;
>                 ^
> In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
>                  from /src/binutils-gdb/gdb/defs.h:28,
>                  from /src/binutils-gdb/gdb/eval.c:20:
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/eval.c:747:2: note: in expansion of macro ‘TRY_CATCH’
>   TRY_CATCH (ex, RETURN_MASK_ERROR)
>   ^
> /src/binutils-gdb/gdb/eval.c:1429:19: error: ‘value’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>      struct value *value = NULL;
>                    ^
> In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
>                  from /src/binutils-gdb/gdb/defs.h:28,
>                  from /src/binutils-gdb/gdb/eval.c:20:
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/eval.c:1430:5: note: in expansion of macro ‘TRY_CATCH’
>      TRY_CATCH (except, RETURN_MASK_ERROR)
>      ^
> /src/binutils-gdb/gdb/eval.c:1846:18: error: ‘value’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>     struct value *value = NULL;
>                   ^
> In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
>                  from /src/binutils-gdb/gdb/defs.h:28,
>                  from /src/binutils-gdb/gdb/eval.c:20:
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/eval.c:1847:4: note: in expansion of macro ‘TRY_CATCH’
>     TRY_CATCH (except, RETURN_MASK_ERROR)
>     ^
> cc1: all warnings being treated as errors
>
>
> --
> Alan Modra
> Australia Development Lab, IBM
James Greenhalgh Nov. 5, 2014, 11 a.m. UTC | #6
On Wed, Nov 05, 2014 at 12:24:16AM +0000, Alan Modra wrote:
> On Mon, Nov 03, 2014 at 06:08:15PM -0800, Siva Chandra wrote:
> > >>        PR c++/17494
> > >>        * eval.c (evaluate_subexp_standard): Evaluate the "object" and
> > >>        the method args also under EVAL_SKIP when evaluating method
> > >>        calls under EVAL_SKIP.
> > 
> > Thanks for the review. Pushed: e0f52461c2467b6610391681fa27cd9b3c5def57
> 
> After this patch, when using gcc-4.9.1 and gcc-5.0 (20140911) I see
> what looks to me to be nonsense errors (ie. I'd suspect a compiler
> bug).  Does anyone else see the same?  Nothing special in configure
> options, x86_64-linux.

For what it is worth, I'm seeing the same with my GCC 4.9.1 (x84_64-linux),
again nothing special in the configure options for GCC:

   ../gcc-4.9.1/configure --enable-checking=release --with-cpu=native 

Thanks,
James

> /src/binutils-gdb/gdb/eval.c: In function ‘evaluate_subexp_standard’:
> /src/binutils-gdb/gdb/eval.c:745:16: error: ‘ret’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>   struct value *ret = NULL;
>                 ^
> In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
>                  from /src/binutils-gdb/gdb/defs.h:28,
>                  from /src/binutils-gdb/gdb/eval.c:20:
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/eval.c:747:2: note: in expansion of macro ‘TRY_CATCH’
>   TRY_CATCH (ex, RETURN_MASK_ERROR)
>   ^
> /src/binutils-gdb/gdb/eval.c:1429:19: error: ‘value’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>      struct value *value = NULL;
>                    ^
> In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
>                  from /src/binutils-gdb/gdb/defs.h:28,
>                  from /src/binutils-gdb/gdb/eval.c:20:
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/eval.c:1430:5: note: in expansion of macro ‘TRY_CATCH’
>      TRY_CATCH (except, RETURN_MASK_ERROR)
>      ^
> /src/binutils-gdb/gdb/eval.c:1846:18: error: ‘value’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>     struct value *value = NULL;
>                   ^
> In file included from /src/binutils-gdb/gdb/common/common-defs.h:49:0,
>                  from /src/binutils-gdb/gdb/defs.h:28,
>                  from /src/binutils-gdb/gdb/eval.c:20:
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: error: ‘buf’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/common/common-exceptions.h:148:20: note: ‘buf’ was declared here
>         SIGJMP_BUF *buf = \
>                     ^
> /src/binutils-gdb/gdb/eval.c:1847:4: note: in expansion of macro ‘TRY_CATCH’
>     TRY_CATCH (except, RETURN_MASK_ERROR)
>     ^
> cc1: all warnings being treated as errors
> 
> 
> -- 
> Alan Modra
> Australia Development Lab, IBM
>
Alan Modra Nov. 5, 2014, 12:54 p.m. UTC | #7
On Wed, Nov 05, 2014 at 11:00:26AM +0000, James Greenhalgh wrote:
> For what it is worth, I'm seeing the same with my GCC 4.9.1 (x84_64-linux),
> again nothing special in the configure options for GCC:

Thanks for the confirmation.  I've opened a gcc bugzilla.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63748
diff mbox

Patch

diff --git a/gdb/eval.c b/gdb/eval.c
index 5906744..ab431c6 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1332,9 +1332,6 @@  evaluate_subexp_standard (struct type *expect_type,
 	  /* First, evaluate the structure into arg2.  */
 	  pc2 = (*pos)++;
 
-	  if (noside == EVAL_SKIP)
-	    goto nosideret;
-
 	  if (op == STRUCTOP_MEMBER)
 	    {
 	      arg2 = evaluate_subexp_for_address (exp, pos, noside);
@@ -1353,7 +1350,10 @@  evaluate_subexp_standard (struct type *expect_type,
 	  arg1 = evaluate_subexp (NULL_TYPE, exp, pos, noside);
 
 	  type = check_typedef (value_type (arg1));
-	  if (TYPE_CODE (type) == TYPE_CODE_METHODPTR)
+	  if (noside == EVAL_SKIP)
+	    tem = 1;  /* Set it to the right arg index so that all arguments
+			 can also be skipped.  */
+	  else if (TYPE_CODE (type) == TYPE_CODE_METHODPTR)
 	    {
 	      if (noside == EVAL_AVOID_SIDE_EFFECTS)
 		arg1 = value_zero (TYPE_TARGET_TYPE (type), not_lval);
@@ -1396,8 +1396,6 @@  evaluate_subexp_standard (struct type *expect_type,
 	  pc2 = (*pos)++;
 	  tem2 = longest_to_int (exp->elts[pc2 + 1].longconst);
 	  *pos += 3 + BYTES_TO_EXP_ELEM (tem2 + 1);
-	  if (noside == EVAL_SKIP)
-	    goto nosideret;
 
 	  if (op == STRUCTOP_STRUCT)
 	    {
@@ -1546,6 +1544,9 @@  evaluate_subexp_standard (struct type *expect_type,
       /* Signal end of arglist.  */
       argvec[tem] = 0;
 
+      if (noside == EVAL_SKIP)
+	goto nosideret;
+
       if (op == OP_ADL_FUNC)
         {
           struct symbol *symp;
diff --git a/gdb/testsuite/gdb.cp/pr17494.cc b/gdb/testsuite/gdb.cp/pr17494.cc
new file mode 100644
index 0000000..77653e1
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/pr17494.cc
@@ -0,0 +1,63 @@ 
+/* This testcase is part of GDB, the GNU debugger.
+
+   Copyright 2014 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/>.  */
+
+
+/* One could use unique_ptr instead, but that requires a GCC which can
+   support "-std=c++11".  */
+
+int
+func (int i, int j)
+{
+  return i + j;
+}
+
+class A
+{
+public:
+  A () { a = 12345; f = &func; }
+  int geta ();
+  int adda (int i);
+
+  int a;
+  int (*f) (int, int);
+};
+
+int
+A::geta ()
+{
+  return a;
+}
+
+int
+A::adda (int i)
+{
+  return a + i;
+}
+
+int
+main ()
+{
+  A a;
+  A *a_ptr = &a;
+  int (A::*m1) ();
+  int (A::*m2) (int);
+
+  m1 = &A::geta;
+  m2 = &A::adda;
+
+  return (a.*m1) () + (a.*m2) (12) + (a.*(&A::f)) (1, 2);  /* Break here  */
+}
diff --git a/gdb/testsuite/gdb.cp/pr17494.exp b/gdb/testsuite/gdb.cp/pr17494.exp
new file mode 100644
index 0000000..7f2e0cf
--- /dev/null
+++ b/gdb/testsuite/gdb.cp/pr17494.exp
@@ -0,0 +1,57 @@ 
+# Copyright 2014 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/>.
+
+# This file is part of the gdb testsuite
+
+if {[skip_cplus_tests]} { continue }
+
+standard_testfile .cc
+
+if {[prepare_for_testing $testfile.exp $testfile $srcfile {debug c++}]} {
+    return -1
+}
+
+if {![runto_main]} {
+    return -1
+}
+
+gdb_breakpoint [gdb_get_line_number "Break here"]
+gdb_continue_to_breakpoint "Break here"
+
+gdb_test "p a.geta()" ".* = 12345" "a.geta()"
+gdb_test "p a_ptr->geta()" ".* = 12345" "a.geta()"
+
+gdb_test "p false ? a.geta() : 123" ".* = 123" "ternop 1"
+gdb_test "p false ? a_ptr->geta() : 123" ".* = 123" "ternop 2"
+gdb_test "p (true ? 123 : a.geta()) + 123" ".* = 246" "ternop 3"
+gdb_test "p (true ? 123 : a_ptr->geta()) + 123" ".* = 246" "ternop 4"
+gdb_test "p false ? (a.*m1)() : 123" ".* = 123" "ternop 5"
+gdb_test "p false ? (a_ptr->*m1)() : 123" ".* = 123" "ternop 6"
+gdb_test "p (true ? 123 : (a.*m1)()) + 123" ".* = 246" "ternop 7"
+gdb_test "p (true ? 123 : (a_ptr->*m1)()) + 123" ".* = 246" "ternop 8"
+
+gdb_test "p false ? a.adda(456) : 123" ".* = 123" "ternop 9"
+gdb_test "p false ? a_ptr->adda(456) : 123" ".* = 123" "ternop 10"
+gdb_test "p (true ? 123 : a.adda(456)) + 123" ".* = 246" "ternop 11"
+gdb_test "p (true ? 123 : a_ptr->adda(456)) + 123" ".* = 246" "ternop 12"
+gdb_test "p false ? (a.*m2)(123) : 123" ".* = 123" "ternop 13"
+gdb_test "p false ? (a_ptr->*m2)(123) : 123" ".* = 123" "ternop 14"
+gdb_test "p (true ? 123 : (a.*m2)(123)) + 123" ".* = 246" "ternop 15"
+gdb_test "p (true ? 123 : (a_ptr->*m2)(123)) + 123" ".* = 246" "ternop 16"
+
+gdb_test "p false ? (a.*(&A::f))(1, 2) : 123" ".* = 123" "ternop 17"
+gdb_test "p false ? (a_ptr->*(&A::f))(1, 2) : 123" ".* = 123" "ternop 18"
+gdb_test "p (true ? 123 : (a.*(&A::f))(1, 2)) + 123" ".* = 246" "ternop 19"
+gdb_test "p (true ? 123 : (a_ptr->*(&A::f))(1, 2)) + 123" ".* = 246" "ternop 20"