unix: Create __bss_start and _end symbols for Mach-O targets.

It's a hack, but can't find a cleaner way to do it.

py/nlrx64.S

@@ -32,6 +32,10 @@
 
 #if !defined(__CYGWIN__)
 
+#if (defined(__APPLE__) && defined(__MACH__))
+#define nlr_jump_fail _nlr_jump_fail
+#endif // (defined(__APPLE__) && defined(__MACH__))
+
 /* uint nlr_push(rdi=nlr_buf_t *nlr) */
 #if !(defined(__APPLE__) && defined(__MACH__))
     .globl  nlr_push

unix/Makefile

@@ -19,8 +19,8 @@ CFLAGS = $(INC) -Wall -Werror -ansi -std=gnu99 -DUNIX $(CFLAGS_MOD) $(COPT)
 
 UNAME_S := $(shell uname -s)
  ifeq ($(UNAME_S),Darwin)
-    LDFLAGS = $(LDFLAGS_MOD) -lm -Wl,-map,$@.map
-else
+    LDFLAGS = $(LDFLAGS_MOD) -lm -Wl,-map,$@.map,-order_file,order.def
+ else
     LDFLAGS = $(LDFLAGS_MOD) -lm -Wl,-Map=$@.map,--cref
  endif
 
@@ -70,6 +70,11 @@ SRC_C = \
 	modsocket.c \
 	$(SRC_MOD)
 
+# Must be the last file
+ifeq ($(UNAME_S),Darwin)
+SRC_C += seg_helpers.c
+endif
+	
 OBJ = $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 
 include ../py/mkrules.mk

unix/order.def

@@ -0,0 +1 @@
+seg_helpers.o: ___bss_start

unix/seg_helpers.c

@@ -0,0 +1,38 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2013, 2014 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/*
+  This is a stub used to create the symbols __bss_start and _end in a Mach-O object file.
+  Thoses are needed by the GC, and should point to the start and end of the bss section.
+  We reach this goal by linking this file last (putting _end at the end...), and using an 
+  order file (order.def) to move __bss_start at the start of bss.
+
+  TODO: Some pragma to do it inline ?
+*/
+
+char __bss_start = 0;
+char _end = 0;
+