diff mbox series

[v2] C++: Fix crash in warn_for_memset within templates (PR c++/83814)

Message ID 1516210020-13394-1-git-send-email-dmalcolm@redhat.com
State New
Headers show
Series [v2] C++: Fix crash in warn_for_memset within templates (PR c++/83814) | expand

Commit Message

David Malcolm Jan. 17, 2018, 5:27 p.m. UTC 
On Wed, 2018-01-17 at 09:28 -0500, Jason Merrill wrote:
> On Wed, Jan 17, 2018 at 5:34 AM, Jakub Jelinek <jakub@redhat.com>
> wrote:
> > On Fri, Jan 12, 2018 at 05:09:24PM -0500, David Malcolm wrote:
> > > PR c++/83814 reports an ICE introduced by the location wrapper
> > > patch
> > > (r256448), affecting certain memset calls within templates.
> > 
> > Note, I think this issue sadly affects a lot of code, so it is
> > quite urgent.
> > 
> > That said, wonder if we really can't do any folding when
> > processing_template_decl, could we e.g. do at least
> > maybe_constant_value,
> > or fold if the expression is not type nor value dependent?
> 
> Yes, in a template we should call fold_non_dependent_expr.
> 
> > BTW, never know if cp_fold_rvalue is a superset of
> > maybe_constant_value or not.
> 
> It is.
> 
> Jason

Thanks.  Here's an updated version of the patch.

Changed in v2:
* use fold_non_dependent_expr in the C++ impl of fold_for_warn
* add some test coverage of folding to g++.dg/wrappers/pr83814.C
* added another testcase (from PR c++/83902)

Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu.
OK for trunk?


gcc/c-family/ChangeLog:
	PR c++/83814
	* c-common.c (fold_for_warn): Move to c/c-fold.c and cp/expr.c.

gcc/c/ChangeLog:
	PR c++/83814
	* c-fold.c (fold_for_warn): Move from c-common.c, reducing to just
	the C part.

gcc/cp/ChangeLog:
	PR c++/83814
	* expr.c (fold_for_warn): Move from c-common.c, reducing to just
	the C++ part.  If processing a template, call
	fold_non_dependent_expr rather than fully folding.

gcc/testsuite/ChangeLog:
	PR c++/83814
	PR c++/83902
	* g++.dg/wrappers/pr83814.C: New test case.
	* g++.dg/wrappers/pr83902.C: New test case.
---
 gcc/c-family/c-common.c                 | 13 ------
 gcc/c/c-fold.c                          | 10 +++++
 gcc/cp/expr.c                           | 15 +++++++
 gcc/testsuite/g++.dg/wrappers/pr83814.C | 70 +++++++++++++++++++++++++++++++++
 gcc/testsuite/g++.dg/wrappers/pr83902.C |  9 +++++
 5 files changed, 104 insertions(+), 13 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/wrappers/pr83814.C
 create mode 100644 gcc/testsuite/g++.dg/wrappers/pr83902.C

Comments

Jason Merrill Jan. 17, 2018, 5:43 p.m. UTC | #1 
OK.

On Wed, Jan 17, 2018 at 12:27 PM, David Malcolm <dmalcolm@redhat.com> wrote:
> On Wed, 2018-01-17 at 09:28 -0500, Jason Merrill wrote:
>> On Wed, Jan 17, 2018 at 5:34 AM, Jakub Jelinek <jakub@redhat.com>
>> wrote:
>> > On Fri, Jan 12, 2018 at 05:09:24PM -0500, David Malcolm wrote:
>> > > PR c++/83814 reports an ICE introduced by the location wrapper
>> > > patch
>> > > (r256448), affecting certain memset calls within templates.
>> >
>> > Note, I think this issue sadly affects a lot of code, so it is
>> > quite urgent.
>> >
>> > That said, wonder if we really can't do any folding when
>> > processing_template_decl, could we e.g. do at least
>> > maybe_constant_value,
>> > or fold if the expression is not type nor value dependent?
>>
>> Yes, in a template we should call fold_non_dependent_expr.
>>
>> > BTW, never know if cp_fold_rvalue is a superset of
>> > maybe_constant_value or not.
>>
>> It is.
>>
>> Jason
>
> Thanks.  Here's an updated version of the patch.
>
> Changed in v2:
> * use fold_non_dependent_expr in the C++ impl of fold_for_warn
> * add some test coverage of folding to g++.dg/wrappers/pr83814.C
> * added another testcase (from PR c++/83902)
>
> Successfully bootstrapped&regrtested on x86_64-pc-linux-gnu.
> OK for trunk?
>
>
> gcc/c-family/ChangeLog:
>         PR c++/83814
>         * c-common.c (fold_for_warn): Move to c/c-fold.c and cp/expr.c.
>
> gcc/c/ChangeLog:
>         PR c++/83814
>         * c-fold.c (fold_for_warn): Move from c-common.c, reducing to just
>         the C part.
>
> gcc/cp/ChangeLog:
>         PR c++/83814
>         * expr.c (fold_for_warn): Move from c-common.c, reducing to just
>         the C++ part.  If processing a template, call
>         fold_non_dependent_expr rather than fully folding.
>
> gcc/testsuite/ChangeLog:
>         PR c++/83814
>         PR c++/83902
>         * g++.dg/wrappers/pr83814.C: New test case.
>         * g++.dg/wrappers/pr83902.C: New test case.
> ---
>  gcc/c-family/c-common.c                 | 13 ------
>  gcc/c/c-fold.c                          | 10 +++++
>  gcc/cp/expr.c                           | 15 +++++++
>  gcc/testsuite/g++.dg/wrappers/pr83814.C | 70 +++++++++++++++++++++++++++++++++
>  gcc/testsuite/g++.dg/wrappers/pr83902.C |  9 +++++
>  5 files changed, 104 insertions(+), 13 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/wrappers/pr83814.C
>  create mode 100644 gcc/testsuite/g++.dg/wrappers/pr83902.C
>
> diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
> index 097d192..858ed68 100644
> --- a/gcc/c-family/c-common.c
> +++ b/gcc/c-family/c-common.c
> @@ -868,19 +868,6 @@ c_get_substring_location (const substring_loc &substr_loc,
>  }
>
>
> -/* Fold X for consideration by one of the warning functions when checking
> -   whether an expression has a constant value.  */
> -
> -tree
> -fold_for_warn (tree x)
> -{
> -  if (c_dialect_cxx ())
> -    return c_fully_fold (x, /*for_init*/false, /*maybe_constp*/NULL);
> -  else
> -    /* The C front-end has already folded X appropriately.  */
> -    return x;
> -}
> -
>  /* Return true iff T is a boolean promoted to int.  */
>
>  bool
> diff --git a/gcc/c/c-fold.c b/gcc/c/c-fold.c
> index 5776f1b..be6a0fc 100644
> --- a/gcc/c/c-fold.c
> +++ b/gcc/c/c-fold.c
> @@ -668,3 +668,13 @@ c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
>      }
>    return ret;
>  }
> +
> +/* Fold X for consideration by one of the warning functions when checking
> +   whether an expression has a constant value.  */
> +
> +tree
> +fold_for_warn (tree x)
> +{
> +  /* The C front-end has already folded X appropriately.  */
> +  return x;
> +}
> diff --git a/gcc/cp/expr.c b/gcc/cp/expr.c
> index 7d79215..b1ab453 100644
> --- a/gcc/cp/expr.c
> +++ b/gcc/cp/expr.c
> @@ -315,3 +315,18 @@ mark_exp_read (tree exp)
>      }
>  }
>
> +/* Fold X for consideration by one of the warning functions when checking
> +   whether an expression has a constant value.  */
> +
> +tree
> +fold_for_warn (tree x)
> +{
> +  /* C++ implementation.  */
> +
> +  /* It's not generally safe to fully fold inside of a template, so
> +     call fold_non_dependent_expr instead.  */
> +  if (processing_template_decl)
> +    return fold_non_dependent_expr (x);
> +
> +  return c_fully_fold (x, /*for_init*/false, /*maybe_constp*/NULL);
> +}
> diff --git a/gcc/testsuite/g++.dg/wrappers/pr83814.C b/gcc/testsuite/g++.dg/wrappers/pr83814.C
> new file mode 100644
> index 0000000..b9f8faa
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/wrappers/pr83814.C
> @@ -0,0 +1,70 @@
> +/* Verify that our memset warnings don't crash when folding
> +   arguments within a template (PR c++/83814).  */
> +
> +// { dg-options "-Wno-int-to-pointer-cast -Wmemset-transposed-args -Wmemset-elt-size" }
> +
> +template <class>
> +void test_1()
> +{
> +  __builtin_memset (int() - char(), 0, 0);
> +}
> +
> +template <class>
> +void test_2()
> +{
> +  __builtin_memset (0, 0, int() - char());
> +}
> +
> +template <class>
> +void test_3 (unsigned a, int c)
> +{
> +  __builtin_memset((char *)c + a, 0, a);
> +}
> +
> +template <class>
> +void test_4 (unsigned a, int c)
> +{
> +  __builtin_memset(0, 0, (char *)c + a);
> +}
> +
> +/* Verify that we warn for -Wmemset-transposed-args inside
> +   a template.  */
> +
> +char buf[1024];
> +
> +template <class>
> +void test_5 ()
> +{
> +  __builtin_memset (buf, sizeof buf, 0); // { dg-warning "transposed parameters" }
> +}
> +
> +/* Adapted from c-c++-common/memset-array.c; verify that
> +   -Wmemset-elt-size works within a template.  */
> +
> +enum a {
> +  a_1,
> +  a_2,
> +  a_n
> +};
> +int t1[20];
> +int t2[a_n];
> +
> +struct s
> +{
> +  int t[20];
> +};
> +
> +template<class>
> +void foo (struct s *s)
> +{
> +  __builtin_memset (t1, 0, 20); // { dg-warning "element size" }
> +
> +  // This case requires reading through an enum value:
> +  __builtin_memset (t2, 0, a_n); // { dg-warning "element size" }
> +
> +  __builtin_memset (s->t, 0, 20); // { dg-warning "element size" }
> +
> +  // These cases require folding of arg2 within a template:
> +  __builtin_memset (t2, 0, a_n + 0); // { dg-warning "element size" }
> +  __builtin_memset (t2, 0, a_n * 1); // { dg-warning "element size" }
> +}
> diff --git a/gcc/testsuite/g++.dg/wrappers/pr83902.C b/gcc/testsuite/g++.dg/wrappers/pr83902.C
> new file mode 100644
> index 0000000..3d334e7
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/wrappers/pr83902.C
> @@ -0,0 +1,9 @@
> +extern "C" void *memset (void *, int, __SIZE_TYPE__);
> +void *p;
> +
> +template <int T>
> +struct B
> +{
> +  void foo () { memset (p, 0, 4 * T * sizeof(float)); }
> +};
> +
> --
> 1.8.5.3
>
diff mbox series

Patch

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 097d192..858ed68 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -868,19 +868,6 @@  c_get_substring_location (const substring_loc &substr_loc,
 }
 
 
-/* Fold X for consideration by one of the warning functions when checking
-   whether an expression has a constant value.  */
-
-tree
-fold_for_warn (tree x)
-{
-  if (c_dialect_cxx ())
-    return c_fully_fold (x, /*for_init*/false, /*maybe_constp*/NULL);
-  else
-    /* The C front-end has already folded X appropriately.  */
-    return x;
-}
-
 /* Return true iff T is a boolean promoted to int.  */
 
 bool
diff --git a/gcc/c/c-fold.c b/gcc/c/c-fold.c
index 5776f1b..be6a0fc 100644
--- a/gcc/c/c-fold.c
+++ b/gcc/c/c-fold.c
@@ -668,3 +668,13 @@  c_fully_fold_internal (tree expr, bool in_init, bool *maybe_const_operands,
     }
   return ret;
 }
+
+/* Fold X for consideration by one of the warning functions when checking
+   whether an expression has a constant value.  */
+
+tree
+fold_for_warn (tree x)
+{
+  /* The C front-end has already folded X appropriately.  */
+  return x;
+}
diff --git a/gcc/cp/expr.c b/gcc/cp/expr.c
index 7d79215..b1ab453 100644
--- a/gcc/cp/expr.c
+++ b/gcc/cp/expr.c
@@ -315,3 +315,18 @@  mark_exp_read (tree exp)
     }
 }
 
+/* Fold X for consideration by one of the warning functions when checking
+   whether an expression has a constant value.  */
+
+tree
+fold_for_warn (tree x)
+{
+  /* C++ implementation.  */
+
+  /* It's not generally safe to fully fold inside of a template, so
+     call fold_non_dependent_expr instead.  */
+  if (processing_template_decl)
+    return fold_non_dependent_expr (x);
+
+  return c_fully_fold (x, /*for_init*/false, /*maybe_constp*/NULL);
+}
diff --git a/gcc/testsuite/g++.dg/wrappers/pr83814.C b/gcc/testsuite/g++.dg/wrappers/pr83814.C
new file mode 100644
index 0000000..b9f8faa
--- /dev/null
+++ b/gcc/testsuite/g++.dg/wrappers/pr83814.C
@@ -0,0 +1,70 @@ 
+/* Verify that our memset warnings don't crash when folding
+   arguments within a template (PR c++/83814).  */
+
+// { dg-options "-Wno-int-to-pointer-cast -Wmemset-transposed-args -Wmemset-elt-size" }
+
+template <class>
+void test_1()
+{
+  __builtin_memset (int() - char(), 0, 0);
+}
+
+template <class>
+void test_2()
+{
+  __builtin_memset (0, 0, int() - char());
+}
+
+template <class>
+void test_3 (unsigned a, int c)
+{
+  __builtin_memset((char *)c + a, 0, a);
+}
+
+template <class>
+void test_4 (unsigned a, int c)
+{
+  __builtin_memset(0, 0, (char *)c + a);
+}
+
+/* Verify that we warn for -Wmemset-transposed-args inside
+   a template.  */
+
+char buf[1024];
+
+template <class>
+void test_5 ()
+{
+  __builtin_memset (buf, sizeof buf, 0); // { dg-warning "transposed parameters" }
+}
+
+/* Adapted from c-c++-common/memset-array.c; verify that 
+   -Wmemset-elt-size works within a template.  */
+
+enum a {
+  a_1,
+  a_2,
+  a_n
+};
+int t1[20];
+int t2[a_n];
+
+struct s
+{
+  int t[20];
+};
+
+template<class>
+void foo (struct s *s)
+{
+  __builtin_memset (t1, 0, 20); // { dg-warning "element size" }
+
+  // This case requires reading through an enum value:
+  __builtin_memset (t2, 0, a_n); // { dg-warning "element size" }
+
+  __builtin_memset (s->t, 0, 20); // { dg-warning "element size" }
+
+  // These cases require folding of arg2 within a template:
+  __builtin_memset (t2, 0, a_n + 0); // { dg-warning "element size" }
+  __builtin_memset (t2, 0, a_n * 1); // { dg-warning "element size" }
+}
diff --git a/gcc/testsuite/g++.dg/wrappers/pr83902.C b/gcc/testsuite/g++.dg/wrappers/pr83902.C
new file mode 100644
index 0000000..3d334e7
--- /dev/null
+++ b/gcc/testsuite/g++.dg/wrappers/pr83902.C
@@ -0,0 +1,9 @@ 
+extern "C" void *memset (void *, int, __SIZE_TYPE__);
+void *p;
+
+template <int T>
+struct B
+{
+  void foo () { memset (p, 0, 4 * T * sizeof(float)); }
+};
+