gdb/fortran: Handle internal function calls

If an convenience function is defined in python (or guile), then
currently this will not work in Fortran, instead the user is given
this message:

  (gdb) set language fortran
  (gdb) p $myfunc (3)
  Cannot perform substring on this type

Compare this to C:

  (gdb) set language c
  (gdb) p $myfunc (3)
  $1 = 1

After this patch we see the same behaviour in both C and Fortran.
I've extended the test to check that all languages can call the
convenience functions - only Fortran was broken.

When calling convenience functions in Fortran we don't need to perform
the same value preparation (passing by pointer) that we would for
calling a native function - passing the real value is fine.

gdb/ChangeLog:

	* eval.c (evaluate_subexp_standard): Handle internal functions
	during Fortran function call handling.

gdb/testsuite/ChangeLog:

	* gdb.python/py-function.exp: Check calling helper function from
	all languages.
	* lib/gdb.exp (gdb_supported_languages): New proc.

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2019-04-01  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* eval.c (evaluate_subexp_standard): Handle internal functions
+	during Fortran function call handling.
+
 2019-04-01  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* NEWS: Mention new internal functions.

gdb/eval.c

@@ -1979,6 +1979,7 @@ evaluate_subexp_standard (struct type *expect_type,
 
 	case TYPE_CODE_PTR:
 	case TYPE_CODE_FUNC:
+	case TYPE_CODE_INTERNAL_FUNCTION:
 	  /* It's a function call.  */
 	  /* Allocate arg vector, including space for the function to be
 	     called in argvec[0] and a terminating NULL.  */
@@ -1996,11 +1997,14 @@ evaluate_subexp_standard (struct type *expect_type,
 		 results in malloc being called with a pointer to an integer
 		 followed by an attempt to malloc the arguments to malloc in
 		 target memory.  Infinite recursion ensues.  */
-	      bool is_artificial =
+	      if (code == TYPE_CODE_PTR || code == TYPE_CODE_FUNC)
-		TYPE_FIELD_ARTIFICIAL (value_type (arg1), tem - 1);
+		{
+		  bool is_artificial
+		    = TYPE_FIELD_ARTIFICIAL (value_type (arg1), tem - 1);
 		  argvec[tem] = fortran_argument_convert (argvec[tem],
 							  is_artificial);
 		}
+	    }
 	  argvec[tem] = 0;	/* signal end of arglist */
 	  if (noside == EVAL_SKIP)
 	    return eval_skip_value (exp);

gdb/testsuite/ChangeLog

@@ -1,3 +1,9 @@
+2019-04-01  Andrew Burgess  <andrew.burgess@embecosm.com>
+
+	* gdb.python/py-function.exp: Check calling helper function from
+	all languages.
+	* lib/gdb.exp (gdb_supported_languages): New proc.
+
 2019-04-01  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* gdb.base/complex-parts.c: New file.

gdb/testsuite/gdb.python/py-function.exp

@@ -51,7 +51,13 @@ gdb_py_test_multiple "input value-returning convenience function" \
   "Double ()" "" \
   "end" ""
 
-gdb_test "print \$double (1)" "= 2" "call value-returning function"
+# Different languages can have different parsers, so lets check that
+# internal functions are understood by every language.  Place auto
+# last in the list so we end up back in 'auto' language mode.
+foreach lang [concat [gdb_supported_languages] auto] {
+    gdb_test_no_output "set language $lang"
+    gdb_test "print \$double (1)" "= 2" "call value-returning function, language = $lang"
+}
 
 gdb_py_test_multiple "input int-returning function" \
   "python" "" \

gdb/testsuite/lib/gdb.exp

@@ -6353,5 +6353,13 @@ proc cd { dir } {
     builtin_cd $dir
 }
 
+# Return a list of all languages supported by GDB, suitable for use in
+# 'set language NAME'.  This doesn't include either the 'local' or
+# 'auto' keywords.
+proc gdb_supported_languages {} {
+    return [list c objective-c c++ d go fortran modula-2 asm pascal \
+		opencl rust minimal ada]
+}
+
 # Always load compatibility stuff.
 load_lib future.exp