Add string_slice class.

The string_slice inherits from array_slice and is used to refer to a
substring of an array that is memory managed elsewhere without modifying
the underlying array.

For example, this is useful in cases such as when needing to refer to a
substring of an attribute in the syntax tree.

Adds some minimal helper functions for string_slice,
such as a strtok alternative, equality operators, strcmp, and a function
to strip whitespace from the beginning and end of a string_slice.

gcc/c-family/ChangeLog:

	* c-format.cc (local_string_slice_node): New node type.
	(asm_fprintf_char_table): New entry.
	(init_dynamic_diag_info): Add support for string_slice.
	* c-format.h (T_STRING_SLICE): New node type.

gcc/ChangeLog:

	* pretty-print.cc (format_phase_2): Add support for string_slice.
	* vec.cc (string_slice::tokenize): New static method.
	(string_slice::strcmp): New static method.
	(string_slice::strip): New method.
	(test_string_slice_initializers): New test.
	(test_string_slice_tokenize): Ditto.
	(test_string_slice_strcmp): Ditto.
	(test_string_slice_equality): Ditto.
	(test_string_slice_inequality): Ditto.
	(test_string_slice_invalid): Ditto.
	(test_string_slice_strip): Ditto.
	(vec_cc_tests): Add new tests.
	* vec.h (class string_slice): New class.

gcc/testsuite/ChangeLog
	* g++.dg/warn/Wformat-gcc_diag-1.C: Add string_slice "%B" format tests.

2 files changed, 8 insertions, 0 deletions

diff --git a/gcc/c-family/c-format.cc b/gcc/c-family/c-format.cc
index a44249a..80430e9 100644
--- a/gcc/c-family/c-format.cc
+++ b/gcc/c-family/c-format.cc
@@ -70,6 +70,7 @@ static GTY(()) tree local_event_ptr_node;
 static GTY(()) tree local_pp_element_ptr_node;
 static GTY(()) tree local_gimple_ptr_node;
 static GTY(()) tree local_cgraph_node_ptr_node;
+static GTY(()) tree local_string_slice_node;
 static GTY(()) tree locus;
 
 static bool decode_format_attr (const_tree, tree, tree, function_format_info *,
@@ -770,6 +771,7 @@ static const format_char_info asm_fprintf_char_table[] =
   { "p",   1, STD_C89, { T89_V,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN  }, "q",  "c",  NULL }, \
   { "r",   1, STD_C89, { T89_C,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN  }, "",    "//cR",   NULL }, \
   { "@",   1, STD_C89, { T_EVENT_PTR,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN  }, "", "\"",   NULL }, \
+  { "B",   1, STD_C89, { T_STRING_SLICE,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN  }, "q", "",   NULL }, \
   { "e",   1, STD_C89, { T_PP_ELEMENT_PTR,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN  }, "", "\"", NULL }, \
   { "<",   0, STD_C89, NOARGUMENTS, "",      "<",   NULL }, \
   { ">",   0, STD_C89, NOARGUMENTS, "",      ">",   NULL }, \
@@ -5211,6 +5213,11 @@ init_dynamic_diag_info (void)
       || local_cgraph_node_ptr_node == void_type_node)
     local_cgraph_node_ptr_node = get_named_type ("cgraph_node");
 
+  /* Similar to the above but for string_slice*.  */
+  if (!local_string_slice_node
+      || local_string_slice_node == void_type_node)
+    local_string_slice_node = get_named_type ("string_slice");
+
   /* Similar to the above but for diagnostic_event_id_t*.  */
   if (!local_event_ptr_node
       || local_event_ptr_node == void_type_node)
diff --git a/gcc/c-family/c-format.h b/gcc/c-family/c-format.h
index 323338c..d44d386 100644
--- a/gcc/c-family/c-format.h
+++ b/gcc/c-family/c-format.h
@@ -317,6 +317,7 @@ struct format_kind_info
 #define T89_G   { STD_C89, NULL, &local_gimple_ptr_node }
 #define T_CGRAPH_NODE   { STD_C89, NULL, &local_cgraph_node_ptr_node }
 #define T_EVENT_PTR    { STD_C89, NULL, &local_event_ptr_node }
+#define T_STRING_SLICE    { STD_C89, NULL, &local_string_slice_node }
 #define T_PP_ELEMENT_PTR    { STD_C89, NULL, &local_pp_element_ptr_node }
 #define T89_T   { STD_C89, NULL, &local_tree_type_node }
 #define T89_V	{ STD_C89, NULL, T_V }