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Fwd: [PATCH] pedantic warning behavior when casting void* to ptr-to-func, 4.8 and 4.9


I just realized I posted the patch in the wrong list.


---------- Forwarded message ----------
From: Daniel Gutson <daniel.gutson@tallertechnologies.com>
Date: Tue, Apr 1, 2014 at 10:43 AM
Subject: [PATCH] pedantic warning behavior when casting void* to
ptr-to-func, 4.8 and 4.9
To: gcc Mailing List <gcc@gcc.gnu.org>


Hi,

   I observed two different behaviors in gcc 4.8.2 and 4.9 regarding
the same issue, IMO both erroneous.

Regarding 4.8.2, #pragma GCC diagnostic ignored "-pedantic" doesn't
work in cases such as:
    void* p = 0;
#pragma GCC diagnostic ignored "-pedantic"
    F* f2 = reinterpret_cast<F*>(p);

(see testcase in the patch).

The attached patch attempts to fix this issue. Since I no longer have
write access, please
apply this for me if correct (is the 4.8 branch still alive for adding fixes?).

Regarding 4.9, gcc fails to complain at all when -pedantic is passed,
even specifying -std=c++03.
Please let me know if this is truly a bug, in which case I could also
fix it for the latest version as well
(if so, please let me know if I should look into trunk or any other branch).

Thanks,

   Daniel.

2014-03-31  Daniel Gutson  <daniel.gutson@tallertechnologies.com>

gcc/cp/
        * typeck.c (build_reinterpret_cast_1): Pass proper argument to
warn() in pedantic.

gcc/testsuite/g++.dg/
        * diagnostic/pedantic.C: New test case.
--- gcc-4.8.2-orig/gcc/cp/typeck.c	2014-03-31 22:29:42.736367936 -0300
+++ gcc-4.8.2/gcc/cp/typeck.c	2014-03-31 14:26:43.536747050 -0300
@@ -6639,7 +6639,7 @@
 	   where possible, and it is necessary in some cases.  DR 195
 	   addresses this issue, but as of 2004/10/26 is still in
 	   drafting.  */
-	warning (0, "ISO C++ forbids casting between pointer-to-function and pointer-to-object");
+	warning (OPT_Wpedantic, "ISO C++ forbids casting between pointer-to-function and pointer-to-object");
       return fold_if_not_in_template (build_nop (type, expr));
     }
   else if (TREE_CODE (type) == VECTOR_TYPE)
--- gcc-4.8.2-orig/gcc/testsuite/g++.dg/diagnostic/pedantic.C	1969-12-31 21:00:00.000000000 -0300
+++ gcc-4.8.2/gcc/testsuite/g++.dg/diagnostic/pedantic.C	2014-03-31 17:24:42.532607344 -0300
@@ -0,0 +1,12 @@
+// { dg-do compile }
+// { dg-options "-pedantic" }
+typedef void F(void);
+
+void foo()
+{
+    void* p = 0;
+    F* f1 = reinterpret_cast<F*>(p);    // { dg-warning "ISO" }
+#pragma GCC diagnostic ignored "-pedantic"
+    F* f2 = reinterpret_cast<F*>(p);
+}
+

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