re PR c++/82466 (Missing warning for re-declaration of built-in function as variable)

2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/82466
	* doc/invoke.texi ([Wbuiltin-declaration-mismatch]): Extend
	description.

/cp
2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/82466
	* decl.c (duplicate_decls): Warn for built-in functions declared as
	non-function, use OPT_Wbuiltin_declaration_mismatch.

	* decl.c (duplicate_decls): Avoid redundant '+' in warning_at.

/c
2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/82466
	* c-decl.c (diagnose_mismatched_decls): Use
	OPT_Wbuiltin_declaration_mismatch.

/testsuite
2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/82466
	* c-c++-common/Wbuiltin-declaration-mismatch-1.c: New.
	* c-c++-common/Wno-builtin-declaration-mismatch-1.c: Likewise.
	* g++.dg/warn/Wbuiltin_declaration_mismatch-1.C: Likewise.
	* g++.dg/parse/builtin2.C: Adjust.
	* g++.old-deja/g++.mike/p811.C: Likewise.

From-SVN: r254057

12 files changed, 63 insertions, 9 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index e0ef3ed..a27df40 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/82466
+	* doc/invoke.texi ([Wbuiltin-declaration-mismatch]): Extend
+	description.
+
 2017-10-24  Wilco Dijkstra  <wdijkstr@arm.com>
 
 	PR rtl-optimization/82396
@@ -55,7 +61,7 @@
 	* tree-outof-ssa.h (always_initialized_rtx_for_ssa_name_p): Delete.
 	* expr.c (expand_expr_real_1) <expand_decl_rtl>: Revert latest change.
 	* loop-iv.c (iv_get_reaching_def): Likewise.
-	* cfgexpand.c (expand_one_ssa_partition): Initialize the RTX if the 
+	* cfgexpand.c (expand_one_ssa_partition): Initialize the RTX if the
 	variable is promoted and the partition contains undefined values.
 
 2017-10-23  Sandra Loosemore  <sandra@codesourcery.com>
@@ -76,7 +82,7 @@
 	(nios2_symbolic_constant_allowed): New.
 	(nios2_symbolic_constant_p): New.
 	(nios2_plus_symbolic_constant_p): New.
-	(nios2_valid_addr_expr_p): Recognize addresses involving 
+	(nios2_valid_addr_expr_p): Recognize addresses involving
 	symbolic constants.
 	(nios2_legitimate_address_p): Likewise, also LO_SUM.
 	(nios2_symbolic_memory_operand_p): New.
@@ -157,7 +163,7 @@
 	* i386.h (processor_costs): Remove sse_move; add xmm_move, ymm_move
 	and zmm_move. Increase size of sse load and store tables;
 	add unaligned load and store tables; add ssemmx_to_integer.
-	* x86-tune-costs.h: Update all entries according to real 
+	* x86-tune-costs.h: Update all entries according to real
 	move latencies from Agner Fog's manual and chip documentation.
 
 2017-10-23  Jakub Jelinek  <jakub@redhat.com>
diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog
index 1f697f1..c260f62 100644
--- a/gcc/c/ChangeLog
+++ b/gcc/c/ChangeLog
@@ -1,3 +1,9 @@
+2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/82466
+	* c-decl.c (diagnose_mismatched_decls): Use
+	OPT_Wbuiltin_declaration_mismatch.
+
 2017-10-12  David Malcolm  <dmalcolm@redhat.com>
 
 	* c-parser.c (c_parser_require): Add "type_is_unique" param and
diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c
index 26b34ab..5c472e6 100644
--- a/gcc/c/c-decl.c
+++ b/gcc/c/c-decl.c
@@ -1837,7 +1837,8 @@ diagnose_mismatched_decls (tree newdecl, tree olddecl,
 	  locate_old_decl (olddecl);
 	}
       else if (TREE_PUBLIC (newdecl))
-	warning (0, "built-in function %q+D declared as non-function",
+	warning (OPT_Wbuiltin_declaration_mismatch,
+		 "built-in function %q+D declared as non-function",
 		 newdecl);
       else
 	warning (OPT_Wshadow, "declaration of %q+D shadows "
diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index e24a194..8c587a3 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,13 @@
 2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>
 
+	PR c++/82466
+	* decl.c (duplicate_decls): Warn for built-in functions declared as
+	non-function, use OPT_Wbuiltin_declaration_mismatch.
+
+	* decl.c (duplicate_decls): Avoid redundant '+' in warning_at.
+
+2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>
+
 	PR c++/80991
 	* pt.c (value_dependent_expression_p, [TRAIT_EXPR]): Handle
 	a TREE_LIST as TRAIT_EXPR_TYPE2.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index a3cc80c..bb48099 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -1431,7 +1431,15 @@ duplicate_decls (tree newdecl, tree olddecl, bool newdecl_is_friend)
 	  /* Avoid warnings redeclaring built-ins which have not been
 	     explicitly declared.  */
 	  if (DECL_ANTICIPATED (olddecl))
-	    return NULL_TREE;
+	    {
+	      if (TREE_PUBLIC (newdecl)
+		  && CP_DECL_CONTEXT (newdecl) == global_namespace)
+		warning_at (DECL_SOURCE_LOCATION (newdecl),
+			    OPT_Wbuiltin_declaration_mismatch,
+			    "built-in function %qD declared as non-function",
+			    newdecl);
+	      return NULL_TREE;
+	    }
 
 	  /* If you declare a built-in or predefined function name as static,
 	     the old definition is overridden, but optionally warn this was a
@@ -1522,7 +1530,7 @@ next_arg:;
 
 	      warning_at (DECL_SOURCE_LOCATION (newdecl),
 			  OPT_Wbuiltin_declaration_mismatch,
-			  "declaration of %q+#D conflicts with built-in "
+			  "declaration of %q#D conflicts with built-in "
 			  "declaration %q#D", newdecl, olddecl);
 	    }
 	  else if ((DECL_EXTERN_C_P (newdecl)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 3a87956..71b2445 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -6320,7 +6320,8 @@ attributes.
 @item -Wno-builtin-declaration-mismatch
 @opindex Wno-builtin-declaration-mismatch
 @opindex Wbuiltin-declaration-mismatch
-Warn if a built-in function is declared with the wrong signature.
+Warn if a built-in function is declared with the wrong signature or 
+as non-function.
 This warning is enabled by default.
 
 @item -Wno-builtin-macro-redefined
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index edf21e9..7801c03 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,14 @@
 2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>
 
+	PR c++/82466
+	* c-c++-common/Wbuiltin-declaration-mismatch-1.c: New.
+	* c-c++-common/Wno-builtin-declaration-mismatch-1.c: Likewise.
+	* g++.dg/warn/Wbuiltin_declaration_mismatch-1.C: Likewise.
+	* g++.dg/parse/builtin2.C: Adjust.
+	* g++.old-deja/g++.mike/p811.C: Likewise.
+
+2017-10-24  Paolo Carlini  <paolo.carlini@oracle.com>
+
 	PR c++/80991
 	* g++.dg/ext/is_trivially_constructible5.C: New.
 
diff --git a/gcc/testsuite/c-c++-common/Wbuiltin-declaration-mismatch-1.c b/gcc/testsuite/c-c++-common/Wbuiltin-declaration-mismatch-1.c
new file mode 100644
index 0000000..63343b8
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wbuiltin-declaration-mismatch-1.c
@@ -0,0 +1,4 @@
+/* PR c++/82466 */
+/* { dg-options "-Wbuiltin-declaration-mismatch" } */
+
+int printf;  /* { dg-warning "declared as non-function" } */
diff --git a/gcc/testsuite/c-c++-common/Wno-builtin-declaration-mismatch-1.c b/gcc/testsuite/c-c++-common/Wno-builtin-declaration-mismatch-1.c
new file mode 100644
index 0000000..6409412
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wno-builtin-declaration-mismatch-1.c
@@ -0,0 +1,4 @@
+/* PR c++/82466 */
+/* { dg-options "-Wno-builtin-declaration-mismatch" } */
+
+int printf;
diff --git a/gcc/testsuite/g++.dg/parse/builtin2.C b/gcc/testsuite/g++.dg/parse/builtin2.C
index c524ea6..daa80bb 100644
--- a/gcc/testsuite/g++.dg/parse/builtin2.C
+++ b/gcc/testsuite/g++.dg/parse/builtin2.C
@@ -1,5 +1,5 @@
 // PR c++/14432
-// { dg-options "" }
+// { dg-options "-Wno-builtin-declaration-mismatch" }
 
 struct Y {}; 
 Y y1; 
diff --git a/gcc/testsuite/g++.dg/warn/Wbuiltin_declaration_mismatch-1.C b/gcc/testsuite/g++.dg/warn/Wbuiltin_declaration_mismatch-1.C
new file mode 100644
index 0000000..713073c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wbuiltin_declaration_mismatch-1.C
@@ -0,0 +1,7 @@
+// PR c++/82466
+// { dg-options "-Wbuiltin-declaration-mismatch" }
+
+namespace N
+{
+  int printf;
+}
diff --git a/gcc/testsuite/g++.old-deja/g++.mike/p811.C b/gcc/testsuite/g++.old-deja/g++.mike/p811.C
index 5c8260a..2ca04ab 100644
--- a/gcc/testsuite/g++.old-deja/g++.mike/p811.C
+++ b/gcc/testsuite/g++.old-deja/g++.mike/p811.C
@@ -1,5 +1,5 @@
 // { dg-do assemble  }
-// { dg-options "" }
+// { dg-options "-Wno-builtin-declaration-mismatch" }
 // This test case caused the compiler to abort at one point in time.
 // prms-id: 811