Add spaceship operator to cp-name-parser.y

While debugging gdb, I saw this:

During symbol reading: unexpected demangled name 'operator<=><std::chrono::_V2::system_clock, std::chrono::duration<long int>, std::chrono::duration<long int> >'

This happens because cp-name-parser.y does not handle the spaceship
operator.  This patch implements this.

Approved-By: John Baldwin <jhb@FreeBSD.org>

gdb/cp-name-parser.y

diff --git a/gdb/cp-name-parser.y b/gdb/cp-name-parser.y
index cf3e8bf..9d0085d 100644
--- a/gdb/cp-name-parser.y
+++ b/gdb/cp-name-parser.y
@@ -297,7 +297,7 @@
 %left '^'
 %left '&'
 %left EQUAL NOTEQUAL
-%left '<' '>' LEQ GEQ
+%left '<' '>' LEQ GEQ SPACESHIP
 %left LSH RSH
 %left '@'
 %left '+' '-'
@@ -451,6 +451,8 @@
 			{ $$ = state->make_operator ("<=", 2); }
 		|	OPERATOR GEQ
 			{ $$ = state->make_operator (">=", 2); }
+		|	OPERATOR SPACESHIP
+			{ $$ = state->make_operator ("<=>", 2); }
 		|	OPERATOR ANDAND
 			{ $$ = state->make_operator ("&&", 2); }
 		|	OPERATOR OROR
@@ -1077,6 +1079,10 @@
 		{ $$ = state->d_binary (">=", $1, $3); }
 	;
 
+exp	:	exp SPACESHIP exp
+		{ $$ = state->d_binary ("<=>", $1, $3); }
+	;
+
 exp	:	exp '<' exp
 		{ $$ = state->d_binary ("<", $1, $3); }
 	;
@@ -1779,6 +1785,7 @@
       return c;
     case '<':
       HANDLE_TOKEN3 ("<<=", ASSIGN_MODIFY);
+      HANDLE_TOKEN3 ("<=>", SPACESHIP);
       HANDLE_TOKEN2 ("<=", LEQ);
       HANDLE_TOKEN2 ("<<", LSH);
       state->lexptr++;
@@ -2049,6 +2056,14 @@
 }
 
 static void
+should_parse (const char *name)
+{
+  std::string err;
+  auto parsed = cp_demangled_name_to_comp (name, &err);
+  SELF_CHECK (parsed != nullptr);
+}
+
+static void
 canonicalize_tests ()
 {
   should_be_the_same ("short int", "short");
@@ -2066,6 +2081,8 @@
 
   should_be_the_same ("something<void ()>", "something<  void()  >");
   should_be_the_same ("something<void ()>", "something<void (void)>");
+
+  should_parse ("void whatever::operator<=><int, int>");
 }
 
 #endif