[PATCH Rust front-end v3 01/46] Use DW_ATE_UTF for the Rust 'char' type

[arthur.cohen@embecosm.com]

From: Tom Tromey <tom@tromey.com>

The Rust 'char' type should use the DWARF DW_ATE_UTF encoding.
---
 gcc/dwarf2out.cc | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/gcc/dwarf2out.cc b/gcc/dwarf2out.cc
index e3920c898f5..a8bccbabca4 100644
--- a/gcc/dwarf2out.cc
+++ b/gcc/dwarf2out.cc
@@ -5600,6 +5600,16 @@ is_fortran (const_tree decl)
   return is_fortran ();
 }
 
+/* Return TRUE if the language is Rust.  */
+
+static inline bool
+is_rust ()
+{
+  unsigned int lang = get_AT_unsigned (comp_unit_die (), DW_AT_language);
+
+  return lang == DW_LANG_Rust || lang == DW_LANG_Rust_old;
+}
+
 /* Return TRUE if the language is Ada.  */
 
 static inline bool
@@ -13231,7 +13241,11 @@ base_type_die (tree type, bool reverse)
 	}
       if (TYPE_STRING_FLAG (type))
 	{
-	  if (TYPE_UNSIGNED (type))
+	  if ((dwarf_version >= 4 || !dwarf_strict)
+	      && is_rust ()
+	      && int_size_in_bytes (type) == 4)
+	    encoding = DW_ATE_UTF;
+	  else if (TYPE_UNSIGNED (type))
 	    encoding = DW_ATE_unsigned_char;
 	  else
 	    encoding = DW_ATE_signed_char;
@@ -25201,6 +25215,13 @@ gen_compile_unit_die (const char *filename)
     }
   else if (strcmp (language_string, "GNU F77") == 0)
     language = DW_LANG_Fortran77;
+  else if (strcmp (language_string, "GNU Rust") == 0)
+    {
+      if (dwarf_version >= 5 || !dwarf_strict)
+	language = DW_LANG_Rust;
+      else
+	language = DW_LANG_Rust_old;
+    }
   else if (dwarf_version >= 3 || !dwarf_strict)
     {
       if (strcmp (language_string, "GNU Ada") == 0)
-- 
2.37.2