Add compiler macro foreign-type-size

The compiler macro is a first-pass that should fix most use cases
without breakage. It checks to see if the foreign type is constant, and
if so, expands into its foreign type size, falling back to the old form
if an error is signaled.

src/early-types.lisp

@@ -164,6 +164,13 @@ Signals an error if FOREIGN-TYPE is undefined."))
   (:documentation
    "Return the size in bytes of a foreign type."))
 
+(define-compiler-macro foreign-type-size (&whole form foreign-type)
+  ;; Don't pass &environment to CONSTANTP or MACROEXPAND as LOAD-TIME-VALUE is
+  ;; executed in a null lexical environment.
+  (if (constantp (macroexpand foreign-type))
+      `(load-time-value (locally (declare (notinline foreign-type-size)) ,form))
+      form))
+
 (defgeneric unparse-type (foreign-type)
   (:documentation
    "Unparse FOREIGN-TYPE to a type specification (symbol or list)."))

tests/misc.lisp

@@ -130,3 +130,33 @@
           (strcpy pointer "xpto")
           (return vector))))
   #(120 112 116 111 0))
+
+;;; Inline foreign-type-size
+
+(deftest foreign-type-size.inline.int
+    (eql (foreign-type-size :int) (locally (declare (notinline foreign-type-size)) (foreign-type-size :int)))
+  t)
+
+(deftest foreign-type-size.inline.uint32
+    (eql (foreign-type-size :uint32) (locally (declare (notinline foreign-type-size)) (foreign-type-size :uint32)))
+  t)
+
+(deftest foreign-type-size.inline.ptrdiff
+    (eql (foreign-type-size :ptrdiff) (locally (declare (notinline foreign-type-size)) (foreign-type-size :ptrdiff)))
+  t)
+
+(deftest foreign-type-size.inline.size
+    (eql (foreign-type-size :size) (locally (declare (notinline foreign-type-size)) (foreign-type-size :size)))
+  t)
+
+(deftest foreign-type-size.inline.offset
+    (eql (foreign-type-size :offset) (locally (declare (notinline foreign-type-size)) (foreign-type-size :offset)))
+  t)
+
+(deftest foreign-type-size.inline.uintptr
+    (eql (foreign-type-size :uintptr) (locally (declare (notinline foreign-type-size)) (foreign-type-size :uintptr)))
+  t)
+
+(deftest foreign-type-size.inline.intptr
+    (eql (foreign-type-size :intptr) (locally (declare (notinline foreign-type-size)) (foreign-type-size :intptr)))
+  t)