Fix Boehm-Weiser gc so that we can use our mprotect() mechanism for deferring signals together with B-W's memory protection and generational garbage collector.

src/CHANGELOG

@@ -28,6 +28,13 @@ ECL 9.5:
    By default a correctable error is signaled and the user is given the
    chance to increase the heap size.
 
+ - Under Mac OS/X, ECL now uses its own modified version of the Boehm-Weiser
+   garbage collector that allows both --enable-gengc and our optimized
+   code for signal handling.
+
+ - New condition EXT:SEGMENTATION-VIOLATION signaled by SIGSEGV and SIGBUS
+   events.
+
 * Bugs fixed:
 
  - Remove an obsolete #if statement for Solaris that broke current builds

src/aclocal.m4

@@ -324,6 +324,9 @@ case "${host_os}" in
 		else
 		  export ABI=mode32
 		fi
+                # The Boehm-Weiser GC library shipped with Fink does not work
+                # well with our signal handler.
+                enable_boehm=included
 		# ECL, due to some of the libraries, does not build on
 		# 64 bit mode on OSX. We prevent GMP using that mode.
 		SONAME="${SHAREDPREFIX}ecl.SOVERSION.${SHAREDEXT}"

src/c/alloc_2.d

@@ -417,7 +417,7 @@ init_alloc(void)
 	GC_start_call_back = (void (*)())finalize_queued;
 	GC_java_finalization = 1;
         GC_oom_fn = out_of_memory;
-        GC_set_warn_proc(no_warnings);
+        /*GC_set_warn_proc(no_warnings);*/
 	GC_enable();
 }
 

src/c/unixint.d

@@ -256,23 +256,11 @@ handler_fn_protype(lisp_signal_handler, int sig, siginfo_t *info, void *aux)
 		cl_error(1, condition);
 		break;
 	}
-	case SIGSEGV: {
-		ecl_frame_ptr destination = frs_sch(OBJNULL);
-		if (destination) {
-			the_env->nvalues = 0;
-			ecl_unwind(the_env, destination);
-		}
-		ecl_internal_error("SIGSEGV without handler to jump to.");
-	}
+	case SIGSEGV:
+                cl_error(1, @'ext::segmentation-violation');
 #ifdef SIGBUS
-	case SIGBUS: {
-		ecl_frame_ptr destination = frs_sch(OBJNULL);
-		if (destination) {
-			the_env->nvalues = 0;
-			ecl_unwind(the_env, destination);
-		}
-		ecl_internal_error("SIGBUS without handler to jump to.");
-	}
+	case SIGBUS:
+                cl_error(1, @'ext::segmentation-violation');
 #endif
 	default:
 		FEerror("Serious signal ~D caught.", 1, MAKE_FIXNUM(sig));

src/clos/conditions.lsp

@@ -538,7 +538,11 @@ returns with NIL."
 
 (define-condition storage-condition (serious-condition) ())
 
-(define-condition ext:segmentation-violation (storage-condition) ())
+(define-condition ext:segmentation-violation (storage-condition)
+  ()
+  (:REPORT
+   (lambda (condition stream)
+     (format stream "Detected access to an invalid or protected memory address."))))
 
 (define-condition ext:stack-overflow (storage-condition)
   ((size :initarg :size :initform 0 :reader ext:stack-overflow-size)

src/configure

@@ -4459,6 +4459,9 @@ case "${host_os}" in
 		else
 		  export ABI=mode32
 		fi
+                # The Boehm-Weiser GC library shipped with Fink does not work
+                # well with our signal handler.
+                enable_boehm=included
 		# ECL, due to some of the libraries, does not build on
 		# 64 bit mode on OSX. We prevent GMP using that mode.
 		SONAME="${SHAREDPREFIX}ecl.SOVERSION.${SHAREDEXT}"

src/gc/os_dep.c

@@ -3808,16 +3808,13 @@ static kern_return_t GC_forward_exception(mach_port_t thread, mach_port_t task,
   behavior = GC_old_exc_ports.behaviors[i];
   flavor = GC_old_exc_ports.flavors[i];
 
-  if(behavior != EXCEPTION_DEFAULT) {
+  if (behavior == EXCEPTION_STATE || behavior == EXCEPTION_STATE_IDENTITY) {
     r = thread_get_state(thread, flavor, thread_state, &thread_state_count);
     if(r != KERN_SUCCESS)
       ABORT("thread_get_state failed in forward_exception");
-    }
+  }
 
   switch(behavior) {
-    case EXCEPTION_DEFAULT:
-      r = exception_raise(port, thread, task, exception, data, data_count);
-      break;
     case EXCEPTION_STATE:
       r = exception_raise_state(port, thread, task, exception, data, data_count,
 				&flavor, thread_state, thread_state_count,
@@ -3829,13 +3826,13 @@ static kern_return_t GC_forward_exception(mach_port_t thread, mach_port_t task,
 					 thread_state_count, thread_state,
 					 &thread_state_count);
       break;
-    default:
-      r = KERN_FAILURE; /* make gcc happy */
-      ABORT("forward_exception: unknown behavior");
+    case EXCEPTION_DEFAULT: /* default signal handlers */
+    default: /* user supplied signal handlers */
+      r = exception_raise(port, thread, task, exception, data, data_count);
       break;
   }
 
-  if(behavior != EXCEPTION_DEFAULT) {
+  if (behavior == EXCEPTION_STATE || behavior == EXCEPTION_STATE_IDENTITY) {
     r = thread_set_state(thread, flavor, thread_state, thread_state_count);
     if(r != KERN_SUCCESS)
       ABORT("thread_set_state failed in forward_exception");