Make primitive redefinition effective through trampoline synthesis

* lisp/loadup.el (dump-mode): Set `comp-enable-subr-trampolines'
	when finished bootstrap.
	* src/data.c (Ffset): Call `comp-enable-subr-trampolines' when
	redefining a subr.
	* src/comp.c (syms_of_comp): Define `comp-subr-trampoline-install'
	symbol.
	(syms_of_comp): Define `comp-enable-subr-trampolines' variable.

lisp/loadup.el

@@ -510,6 +510,11 @@ lost after dumping")))
                         ((equal dump-mode "bootstrap") "emacs")
                         ((equal dump-mode "pbootstrap") "bootstrap-emacs.pdmp")
                         (t (error "unrecognized dump mode %s" dump-mode)))))
+      (when (and (boundp 'comp-ctxt)
+                 (equal dump-mode "pdump"))
+        ;; Don't enable this before bootstrap is completed the as the
+        ;; compiler infrastructure may not be usable.
+        (setq comp-enable-subr-trampolines t))
       (message "Dumping under the name %s" output)
       (condition-case ()
           (delete-file output)

src/comp.c

@@ -5141,6 +5141,7 @@ native compiled one.  */);
   DEFSYM (Qlate, "late");
   DEFSYM (Qlambda_fixup, "lambda-fixup");
   DEFSYM (Qgccjit, "gccjit");
+  DEFSYM (Qcomp_subr_trampoline_install, "comp-subr-trampoline-install")
 
   /* To be signaled by the compiler.  */
   DEFSYM (Qnative_compiler_error, "native-compiler-error");
@@ -5246,6 +5247,11 @@ The last directory of this list is assumed to be the system one.  */);
      dump reload.  */
   Vcomp_eln_load_path = Fcons (build_string ("../native-lisp/"), Qnil);
 
+  DEFVAR_BOOL ("comp-enable-subr-trampolines", comp_enable_subr_trampolines,
+	       doc: /* When non-nil enable trampoline synthesis
+		       triggerd by `fset' making primitives
+		       redefinable effectivelly.  */);
+
   DEFVAR_LISP ("comp-installed-trampolines-h", Vcomp_installed_trampolines_h,
 	       doc: /* Hash table subr-name -> bool.  */);
   Vcomp_installed_trampolines_h = CALLN (Fmake_hash_table);

src/data.c

@@ -775,6 +775,13 @@ DEFUN ("fset", Ffset, Sfset, 2, 2, 0,
 
   eassert (valid_lisp_object_p (definition));
 
+#ifdef HAVE_NATIVE_COMP
+  if (comp_enable_subr_trampolines
+      && SUBRP (function)
+      && !SUBR_NATIVE_COMPILEDP (function))
+    CALLN (Ffuncall, Qcomp_subr_trampoline_install, symbol);
+#endif
+
   set_symbol_function (symbol, definition);
 
   return definition;