PR43651: add warning for duplicate qualifier

gcc/c/

	PR c/43651
	* c-decl.c (declspecs_add_qual): Warn when -Wduplicate-decl-specifier
	is enabled.
	* c-errors.c (pedwarn_c90): Return true if warned.
	* c-tree.h (pedwarn_c90): Change return type to bool.
	(enum c_declspec_word): Add new enumerator cdw_atomic.

gcc/

	PR c/43651
	* doc/invoke.texi (Wduplicate-decl-specifier): Document new option.

gcc/testsuite/

	PR c/43651
	* gcc.dg/Wduplicate-decl-specifier-c11.c: New test.
	* gcc.dg/Wduplicate-decl-specifier.c: Likewise.

gcc/c-family/

	PR c/43651
	* c.opt (Wduplicate-decl-specifier): New option.

From-SVN: r236142

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 08e875864e441c257e418e2cecd8197fb696ddce..b6571813d52f7d1ad8ff28ece68d0a15cc66f58f 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2016-05-11  Mikhail Maltsev  <maltsevm@gmail.com>
+
+       PR c/43651
+       * doc/invoke.texi (Wduplicate-decl-specifier): Document new option.
+
 2016-05-11  Uros Bizjak  <ubizjak@gmail.com>
 
        * config/i386/i386.c (legitimize_pic_address): Use

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 0b31517a1188f20005340a7a6fa27038df5294b3..c8dd0bebae0082b6de56411dc3f41a9b0fba31de 100644 (file)
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2016-05-11  Mikhail Maltsev  <maltsevm@gmail.com>
+
+       PR c/43651
+       * c.opt (Wduplicate-decl-specifier): New option.
+
 2016-05-11  Marek Polacek  <polacek@redhat.com>
 
        PR c++/71024

diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
index bdc6ee0f83bc948323ba47460bd0e458b3b0f4fa..918df16ea99af7bd61312ed6b760b086669d9b23 100644 (file)
--- a/gcc/c-family/c.opt
+++ b/gcc/c-family/c.opt
@@ -1008,6 +1008,10 @@ Wsubobject-linkage
 C++ ObjC++ Var(warn_subobject_linkage) Warning Init(1)
 Warn if a class type has a base or a field whose type uses the anonymous namespace or depends on a type with no linkage.
 
+Wduplicate-decl-specifier
+C ObjC Var(warn_duplicate_decl_specifier) Warning LangEnabledBy(C ObjC,Wall)
+Warn when a declaration has duplicate const, volatile, restrict or _Atomic specifier.
+
 ansi
 C ObjC C++ ObjC++
 A synonym for -std=c89 (for C) or -std=c++98 (for C++).

diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 70444002652bb499179655f4723ff2de61218b57..d17cd925c5b6996966ee7877318da1466569acaf 100644 (file)
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,12 @@
+2016-05-11  Mikhail Maltsev  <maltsevm@gmail.com>
+
+       PR c/43651
+       * c-decl.c (declspecs_add_qual): Warn when -Wduplicate-decl-specifier
+       is enabled.
+       * c-errors.c (pedwarn_c90): Return true if warned.
+       * c-tree.h (pedwarn_c90): Change return type to bool.
+       (enum c_declspec_word): Add new enumerator cdw_atomic.
+
 2016-05-11  Marek Polacek  <polacek@redhat.com>
 
        PR c++/71024

diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 6ba0e0e52a55be2de5399bda32bb743faa1bf7ec..88424a784c94c994d34665e1e1659ecf4c581601 100644 (file)
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -9515,32 +9515,48 @@ declspecs_add_qual (source_location loc,
   gcc_assert (TREE_CODE (qual) == IDENTIFIER_NODE
              && C_IS_RESERVED_WORD (qual));
   i = C_RID_CODE (qual);
+  location_t prev_loc = 0;
   switch (i)
     {
     case RID_CONST:
       dupe = specs->const_p;
       specs->const_p = true;
+      prev_loc = specs->locations[cdw_const];
       specs->locations[cdw_const] = loc;
       break;
     case RID_VOLATILE:
       dupe = specs->volatile_p;
       specs->volatile_p = true;
+      prev_loc = specs->locations[cdw_volatile];
       specs->locations[cdw_volatile] = loc;
       break;
     case RID_RESTRICT:
       dupe = specs->restrict_p;
       specs->restrict_p = true;
+      prev_loc = specs->locations[cdw_restrict];
       specs->locations[cdw_restrict] = loc;
       break;
     case RID_ATOMIC:
       dupe = specs->atomic_p;
       specs->atomic_p = true;
+      prev_loc = specs->locations[cdw_atomic];
+      specs->locations[cdw_atomic] = loc;
       break;
     default:
       gcc_unreachable ();
     }
   if (dupe)
-    pedwarn_c90 (loc, OPT_Wpedantic, "duplicate %qE", qual);
+    {
+      bool warned = pedwarn_c90 (loc, OPT_Wpedantic,
+                                "duplicate %qE declaration specifier", qual);
+      if (!warned
+         && warn_duplicate_decl_specifier
+         && prev_loc >= RESERVED_LOCATION_COUNT
+         && !from_macro_expansion_at (prev_loc)
+         && !from_macro_expansion_at (loc))
+       warning_at (loc, OPT_Wduplicate_decl_specifier,
+                   "duplicate %qE declaration specifier", qual);
+    }
   return specs;
 }
 

diff --git a/gcc/c/c-errors.c b/gcc/c/c-errors.c
index d5e78b875eedd3fa3337e9eea492087520ec4636..af157c00fc838df721698a74f29a8b02d4dec915 100644 (file)
--- a/gcc/c/c-errors.c
+++ b/gcc/c/c-errors.c
@@ -71,11 +71,12 @@ pedwarn_c99 (location_t location, int opt, const char *gmsgid, ...)
    ISO C99 but not supported in ISO C90, thus we explicitly don't pedwarn
    when C99 is specified.  (There is no flag_c90.)  */
 
-void
+bool
 pedwarn_c90 (location_t location, int opt, const char *gmsgid, ...)
 {
   diagnostic_info diagnostic;
   va_list ap;
+  bool warned = false;
   rich_location richloc (line_table, location);
 
   va_start (ap, gmsgid);
@@ -92,6 +93,7 @@ pedwarn_c90 (location_t location, int opt, const char *gmsgid, ...)
                               ? DK_PEDWARN : DK_WARNING);
          diagnostic.option_index = opt;
          report_diagnostic (&diagnostic);
+         warned = true;
          goto out;
        }
     }
@@ -114,7 +116,9 @@ pedwarn_c90 (location_t location, int opt, const char *gmsgid, ...)
       diagnostic_set_info (&diagnostic, gmsgid, &ap, &richloc, DK_PEDWARN);
       diagnostic.option_index = opt;
       report_diagnostic (&diagnostic);
+      warned = true;
     }
 out:
   va_end (ap);
+  return warned;
 }

diff --git a/gcc/c/c-tree.h b/gcc/c/c-tree.h
index 07d0f65609459cf5e8a7a5d2765aee48981138bc..d97e5755bb784e870d42df700c07b9111dc150c0 100644 (file)
--- a/gcc/c/c-tree.h
+++ b/gcc/c/c-tree.h
@@ -253,6 +253,7 @@ enum c_declspec_word {
   cdw_const,
   cdw_volatile,
   cdw_restrict,
+  cdw_atomic,
   cdw_saturating,
   cdw_alignas,
   cdw_address_space,
@@ -716,7 +717,7 @@ extern void c_bind (location_t, tree, bool);
 extern bool tag_exists_p (enum tree_code, tree);
 
 /* In c-errors.c */
-extern void pedwarn_c90 (location_t, int opt, const char *, ...)
+extern bool pedwarn_c90 (location_t, int opt, const char *, ...)
     ATTRIBUTE_GCC_DIAG(3,4);
 extern bool pedwarn_c99 (location_t, int opt, const char *, ...)
     ATTRIBUTE_GCC_DIAG(3,4);

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d3e25380df62bff80acbfb1e5c40e3e5f4dfeafa..c72ec5b3d5b6132ae998bd703368a87a57e779b8 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -3542,6 +3542,7 @@ Options} and @ref{Objective-C and Objective-C++ Dialect Options}.
 -Wc++11-compat  -Wc++14-compat@gol
 -Wchar-subscripts  @gol
 -Wcomment  @gol
+-Wduplicate-decl-specifier @r{(C and Objective-C only)} @gol
 -Wenum-compare @r{(in C/ObjC; this is on by default in C++)} @gol
 -Wformat   @gol
 -Wimplicit @r{(C and Objective-C only)} @gol
@@ -3699,6 +3700,13 @@ float area(float radius)
 the compiler performs the entire computation with @code{double}
 because the floating-point literal is a @code{double}.
 
+@item -Wduplicate-decl-specifier @r{(C and Objective-C only)}
+@opindex Wduplicate-decl-specifier
+@opindex Wno-duplicate-decl-specifier
+Warn if a declaration has duplicate @code{const}, @code{volatile},
+@code{restrict} or @code{_Atomic} specifier.  This warning is enabled by
+@option{-Wall}.
+
 @item -Wformat
 @itemx -Wformat=@var{n}
 @opindex Wformat

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 9addbee9f091efab702baf05188aeebc88e45c0d..b9c541f8c5a9979e7b1fd238efe52ad636e4aa24 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2016-05-11  Mikhail Maltsev  <maltsevm@gmail.com>
+
+       PR c/43651
+       * gcc.dg/Wduplicate-decl-specifier-c11.c: New test.
+       * gcc.dg/Wduplicate-decl-specifier.c: Likewise.
+
 2016-05-11  Uros Bizjak  <ubizjak@gmail.com>
 
        * gcc.target/i386/sse-13.c: Add dg-add-options bind_pic_locally

diff --git a/gcc/testsuite/gcc.dg/Wduplicate-decl-specifier-c11.c b/gcc/testsuite/gcc.dg/Wduplicate-decl-specifier-c11.c
new file mode 100644 (file)
index 0000000..c2db525
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wduplicate-decl-specifier-c11.c
@@ -0,0 +1,27 @@
+/* { dg-do compile } */
+/* { dg-options "-std=c11 -Wduplicate-decl-specifier" } */
+
+typedef _Atomic int AT1;
+#define AT2 _Atomic int
+
+void
+foo (void)
+{
+  _Atomic AT1 x1;
+  _Atomic AT2 x2;
+  AT1 _Atomic x3;
+  AT2 _Atomic x4;
+  _Atomic int _Atomic x5; /* { dg-warning "duplicate ._Atomic." } */
+}
+
+void a1(_Atomic AT1 t) { }
+void a2(_Atomic AT2 t) { }
+void a3(AT1 _Atomic t) { }
+void a4(AT2 _Atomic t) { }
+void a5(_Atomic int _Atomic t) { }  /* { dg-warning "duplicate ._Atomic." } */
+
+typedef _Atomic AT1 AAT1;
+typedef _Atomic AT2 AAT2;
+typedef AT1 _Atomic AT1A;
+typedef AT2 _Atomic AT2A;
+typedef _Atomic int _Atomic AIA;    /* { dg-warning "duplicate ._Atomic." } */

diff --git a/gcc/testsuite/gcc.dg/Wduplicate-decl-specifier.c b/gcc/testsuite/gcc.dg/Wduplicate-decl-specifier.c
new file mode 100644 (file)
index 0000000..d7a3919
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Wduplicate-decl-specifier.c
@@ -0,0 +1,63 @@
+/* PR43651 */
+/* { dg-do compile } */
+/* { dg-options "-Wduplicate-decl-specifier" } */
+
+typedef const int CT1;
+#define CT2 const int
+typedef volatile int VT1;
+#define VT2 volatile int
+typedef char *restrict RT1;
+#define RT2 char *restrict
+
+void
+foo (void)
+{
+  const CT1 x1;
+  const CT2 x2;
+  CT1 const x3;
+  CT2 const x4;
+  const int const x5; /* { dg-warning "duplicate .const." } */
+  const int *const x6;
+  volatile VT1 y1;
+  volatile VT2 y2;
+  VT1 volatile y3;
+  VT2 volatile y4;
+  volatile int volatile y5; /* { dg-warning "duplicate .volatile." } */
+  volatile int *volatile y6;
+  RT1 restrict r1;
+  RT2 restrict r2;
+  restrict RT1 r3;
+  /* "restrict RT2" is invalid */
+  char *restrict restrict r4; /* { dg-warning "duplicate .restrict." } */
+  char *restrict *restrict r5;
+}
+
+void c1(const CT1 t) { }
+void c2(const CT2 t) { }
+void c3(CT1 const t) { }
+void c4(CT2 const t) { }
+void c5(const int const t) { }  /* { dg-warning "duplicate .const." } */
+void v1(volatile VT1 t) { }
+void v2(volatile VT2 t) { }
+void v3(VT1 volatile t) { }
+void v4(VT2 volatile t) { }
+void v5(volatile int volatile t) { } /* { dg-warning "duplicate .volatile." } */
+void r1(restrict RT1 t) { }
+void r2(RT1 restrict t) { }
+void r3(RT2 restrict t) { }
+void r4(char *restrict restrict t) { }  /* { dg-warning "duplicate .restrict." } */
+
+typedef const CT1 CCT1;
+typedef const CT2 CCT2;
+typedef CT1 const CT1C;
+typedef CT2 const CT2C;
+typedef const int const CIC;    /* { dg-warning "duplicate .const." } */
+typedef volatile VT1 VVT1;
+typedef volatile VT2 VVT2;
+typedef VT1 volatile VT1V;
+typedef VT2 volatile VT2V;
+typedef volatile int volatile VIV; /* { dg-warning "duplicate .volatile." } */
+typedef RT1 restrict RT1R;
+typedef RT2 restrict RT2R;
+typedef restrict RT1 RRT1;
+typedef int *restrict restrict IRR; /* { dg-warning "duplicate .restrict." } */