From: Andrea Corallo <akrl@sdf.org>
Date: Wed, 13 May 2020 07:52:47 +0000 (+0100)
Subject: Sanity check on lambdas fixups
X-Git-Tag: emacs-28.0.90~2727^2~639
X-Git-Url: http://git.eshelyaron.com/gitweb/?a=commitdiff_plain;h=e351a12216519d3ed09892752ce0b137f6672986;p=emacs.git

Sanity check on lambdas fixups

	* src/pdumper.c (dump_do_dump_relocation): While fixing up lambda
	relocation verify placeholder coherency.

	* src/comp.c (syms_of_comp): Define symbol 'lambda-fixup'.

	* lisp/emacs-lisp/comp.el (comp-finalize-container): Leave a
	lambda-fixup as placeholder in the relocation as a sanity check.
---

diff --git a/lisp/emacs-lisp/comp.el b/lisp/emacs-lisp/comp.el
index d546218940b..7de8e0177c1 100644
--- a/lisp/emacs-lisp/comp.el
+++ b/lisp/emacs-lisp/comp.el
@@ -2158,7 +2158,7 @@ These are substituted with a normal 'set' op."
                  ;; from the corresponding m-var.
                  collect (if (gethash obj
                                       (comp-ctxt-byte-func-to-func-h comp-ctxt))
-                             nil
+                             'lambda-fixup
                            obj))))
 
 (defun comp-finalize-relocs ()
diff --git a/src/comp.c b/src/comp.c
index 3a362fd0957..d1f8fe23f0d 100644
--- a/src/comp.c
+++ b/src/comp.c
@@ -3891,6 +3891,7 @@ syms_of_comp (void)
   DEFSYM (Qfixnum, "fixnum");
   DEFSYM (Qscratch, "scratch");
   DEFSYM (Qlate, "late");
+  DEFSYM (Qlambda_fixup, "lambda-fixup");
 
   /* To be signaled by the compiler.  */
   DEFSYM (Qnative_compiler_error, "native-compiler-error");
diff --git a/src/pdumper.c b/src/pdumper.c
index a1b71e87ac6..a6d12b6ea0c 100644
--- a/src/pdumper.c
+++ b/src/pdumper.c
@@ -5342,11 +5342,14 @@ dump_do_dump_relocation (const uintptr_t dump_base,
 	if (!NILP (lambda_data_idx))
 	  {
 	    /* This is an anonymous lambda.
-	       We must fixup data_vec so the lambda can be referenced
+	       We must fixup d_reloc_imp so the lambda can be referenced
 	       by code.  */
 	    Lisp_Object tem;
 	    XSETSUBR (tem, subr);
-	    comp_u->data_imp_relocs[XFIXNUM (lambda_data_idx)] = tem;
+	    Lisp_Object *fixup =
+	      &(comp_u->data_imp_relocs[XFIXNUM (lambda_data_idx)]);
+	    eassert (EQ (*fixup, Qlambda_fixup));
+	    *fixup = tem;
 	    Fputhash (tem, Qnil, comp_u->lambda_gc_guard);
 	  }
 	break;