Add expected type parameter to evaluate_expression

While working on the expression rewrite, I found a few spots that
called the internal functions of the expression evaluator, just to
pass in an expected type.  This patch adds a parameter to
evaluate_expression so that these functions can avoid this dependency.

Regression tested on x86-64 Fedora 28.

gdb/ChangeLog
2020-12-15  Tom Tromey  <tom@tromey.com>

	* stap-probe.c (stap_probe::evaluate_argument): Use
	evaluate_expression.
	* dtrace-probe.c (dtrace_probe::evaluate_argument): Use
	evaluate_expression.
	* value.h (evaluate_expression): Add expect_type parameter.
	* objc-lang.c (print_object_command): Call evaluate_expression.
	* eval.c (evaluate_expression): Add expect_type parameter.

1 files changed, 8 insertions, 1 deletions

diff --git a/gdb/value.h b/gdb/value.h
index 25937f3..98012a5 100644
--- a/gdb/value.h
+++ b/gdb/value.h
@@ -905,7 +905,14 @@ extern int using_struct_return (struct gdbarch *gdbarch,
 				struct value *function,
 				struct type *value_type);
 
-extern struct value *evaluate_expression (struct expression *exp);
+/* Evaluate the expression EXP.  If set, EXPECT_TYPE is passed to the
+   outermost operation's evaluation.  This is ignored by most
+   operations, but may be used, e.g., to determine the type of an
+   otherwise untyped symbol.  The caller should not assume that the
+   returned value has this type.  */
+
+extern struct value *evaluate_expression (struct expression *exp,
+					  struct type *expect_type = nullptr);
 
 extern struct value *evaluate_type (struct expression *exp);