PR c++/87996 - size of array is negative error when SIZE_MAX/2 < sizeof(array) <= SIZE_MAX

gcc/ChangeLog:

	PR c++/87996
	* builtins.c (max_object_size): Move from here...
	* builtins.h (max_object_size): ...and here...
	* tree.c (max_object_size): ...to here...
	* tree.h (max_object_size): ...and here.

gcc/c-family/ChangeLog:

	PR c++/87996
	* c-common.c (invalid_array_size_error): New function.
	(valid_array_size_p): Call it.  Handle size as well as type.
	* c-common.h (valid_constant_size_p): New function.
	(enum cst_size_error): New type.

gcc/cp/ChangeLog:

	PR c++/87996
	* decl.c (compute_array_index_type_loc): Preserve signed sizes
	for diagnostics.  Call valid_array_size_p instead of error.
	* init.c (build_new_1): Compute size for diagnostic.  Call
	invalid_array_size_error
	(build_new): Call valid_array_size_p instead of error.

gcc/testsuite/ChangeLog:

	PR c++/87996
	* c-c++-common/array-5.c: New test.
	* c-c++-common/pr68107.c: Adjust text of diagnostics.
	* g++.dg/init/new38.C: Same.
	* g++.dg/init/new43.C: Same.
	* g++.dg/init/new44.C: Same.
	* g++.dg/init/new46.C: Same.
	* g++.dg/other/large-size-array.C: Same.
	* g++.dg/other/new-size-type.C: Same.
	* g++.dg/template/array30.C: Same.
	* g++.dg/template/array32.C: New test.
	* g++.dg/template/dependent-name3.C: Adjust.
	* gcc.dg/large-size-array-3.c: Same.
	* gcc.dg/large-size-array-5.c: Same.
	* gcc.dg/large-size-array.c: Same.
	* g++.old-deja/g++.brendan/array1.C: Same.
	* g++.old-deja/g++.mike/p6149.C: Same.

From-SVN: r268774

1 files changed, 30 insertions, 12 deletions

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 65ba812..4038197 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -9652,17 +9652,21 @@ static tree
 compute_array_index_type_loc (location_t name_loc, tree name, tree size,
 			      tsubst_flags_t complain)
 {
-  tree itype;
-  tree osize = size;
-
   if (error_operand_p (size))
     return error_mark_node;
 
+  /* The type of the index being computed.  */
+  tree itype;
+
+  /* The original numeric size as seen in the source code before
+     conversion to size_t.  */
+  tree origsize = size;
+
   location_t loc = cp_expr_loc_or_loc (size, name ? name_loc : input_location);
 
   if (!type_dependent_expression_p (size))
     {
-      osize = size = mark_rvalue_use (size);
+      origsize = size = mark_rvalue_use (size);
 
       if (cxx_dialect < cxx11 && TREE_CODE (size) == NOP_EXPR
 	  && TREE_SIDE_EFFECTS (size))
@@ -9679,7 +9683,7 @@ compute_array_index_type_loc (location_t name_loc, tree name, tree size,
 				       /*manifestly_const_eval=*/true);
 
 	  if (!TREE_CONSTANT (size))
-	    size = osize;
+	    size = origsize;
 	}
 
       if (error_operand_p (size))
@@ -9740,16 +9744,30 @@ compute_array_index_type_loc (location_t name_loc, tree name, tree size,
   /* Normally, the array-bound will be a constant.  */
   if (TREE_CODE (size) == INTEGER_CST)
     {
-      /* An array must have a positive number of elements.  */
-      if (!valid_constant_size_p (size))
+      /* The size to use in diagnostics that reflects the constant
+	 size used in the source, rather than SIZE massaged above.  */
+      tree diagsize = size;
+
+      /* If the original size before conversion to size_t was signed
+	 and negative, convert it to ssizetype to restore the sign.  */
+      if (!TYPE_UNSIGNED (TREE_TYPE (origsize))
+	  && TREE_CODE (size) == INTEGER_CST
+	  && tree_int_cst_sign_bit (size))
+	{
+	  diagsize = fold_convert (ssizetype, size);
+
+	  /* Clear the overflow bit that may have been set as a result
+	     of the conversion from the sizetype of the new size to
+	     ssizetype.  */
+	  TREE_OVERFLOW (diagsize) = false;
+	}
+
+      /* Verify that the array has a positive number of elements
+	 and issue the appropriate diagnostic if it doesn't.  */
+      if (!valid_array_size_p (loc, diagsize, name, (complain & tf_error)))
 	{
 	  if (!(complain & tf_error))
 	    return error_mark_node;
-
-	  if (name)
-	    error_at (loc, "size of array %qD is negative", name);
-	  else
-	    error_at (loc, "size of array is negative");
 	  size = integer_one_node;
 	}
       /* As an extension we allow zero-sized arrays.  */