Remove obsolete bss-related code/build features

GC for unix/windows builds doesn't make use of the bss section anymore,
so we do not need the (sometimes complicated) build features and code related to it

py/gc.c

@@ -695,11 +695,9 @@ void gc_dump_alloc_table(void) {
             case AT_FREE: c = '.'; break;
             /* this prints out if the object is reachable from BSS or STACK (for unix only)
             case AT_HEAD: {
-                extern char __bss_start, _end;
-                extern char *stack_top;
                 c = 'h';
-                void **ptrs = (void**)&__bss_start;
-                mp_uint_t len = ((mp_uint_t)&_end - (mp_uint_t)&__bss_start) / sizeof(mp_uint_t);
+                void **ptrs = (void**)(void*)&mp_state_ctx;
+                mp_uint_t len = offsetof(mp_state_ctx_t, vm.stack_top) / sizeof(mp_uint_t);
                 for (mp_uint_t i = 0; i < len; i++) {
                     mp_uint_t ptr = (mp_uint_t)ptrs[i];
                     if (VERIFY_PTR(ptr) && BLOCK_FROM_PTR(ptr) == bl) {
@@ -709,7 +707,7 @@ void gc_dump_alloc_table(void) {
                 }
                 if (c == 'h') {
                     ptrs = (void**)&c;
-                    len = ((mp_uint_t)stack_top - (mp_uint_t)&c) / sizeof(mp_uint_t);
+                    len = ((mp_uint_t)MP_STATE_VM(stack_top) - (mp_uint_t)&c) / sizeof(mp_uint_t);
                     for (mp_uint_t i = 0; i < len; i++) {
                         mp_uint_t ptr = (mp_uint_t)ptrs[i];
                         if (VERIFY_PTR(ptr) && BLOCK_FROM_PTR(ptr) == bl) {

unix/Makefile

@@ -35,8 +35,8 @@ endif
 # if necessary override the value of 'CC' set in py/mkenv.mk
 ifeq ($(UNAME_S),Darwin)
 CC = clang
-# Use clang syntax for map file and set osx specific flags
-LDFLAGS_ARCH = -Wl,-order_file,$(BUILD)/order.def -Wl,-map,$@.map
+# Use clang syntax for map file
+LDFLAGS_ARCH = -Wl,-map,$@.map
 else
 # Use gcc syntax for map file
 LDFLAGS_ARCH = -Wl,-Map=$@.map,--cref
@@ -92,17 +92,6 @@ SRC_C = \
 	alloc.c \
 	$(SRC_MOD)
 
-ifeq ($(UNAME_S),Darwin)
-# Must be the last file in list of sources
-SRC_C += seg_helpers.c
-
-# making seg_helpers.c rely on order.def will force order.def to be created
-seg_helpers.c: $(BUILD)/order.def
-
-# create order.def in build directory
-$(BUILD)/order.def:
-	$(Q)echo "seg_helpers.o: ___bss_start" > $@
-endif
 
 OBJ = $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 

unix/seg_helpers.c

@@ -1,38 +0,0 @@
-/*
- * 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;
-

windows/Makefile

@@ -37,7 +37,6 @@ SRC_C = \
 	realpath.c \
 	init.c \
 	sleep.c \
-	bss.c \
 
 OBJ = $(PY_O) $(addprefix $(BUILD)/, $(SRC_C:.c=.o))
 

windows/bss.c

@@ -1,71 +0,0 @@
-/*
-* 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.
-*/
-
-#include "py/nlr.h"
-#include "py/obj.h"
-#include <windows.h>
-
-IMAGE_NT_HEADERS *header_from_memory(const char *module) {
-    BYTE *base_addr = (BYTE*)GetModuleHandleA(module);
-    IMAGE_DOS_HEADER *dos_header = (IMAGE_DOS_HEADER*)base_addr;
-    return (IMAGE_NT_HEADERS*)(base_addr + dos_header->e_lfanew);
-}
-
-IMAGE_SECTION_HEADER *find_section(IMAGE_NT_HEADERS *nt_header, const char *name) {
-    int i;
-    IMAGE_SECTION_HEADER *section = IMAGE_FIRST_SECTION(nt_header);
-    for (i = 0; i < nt_header->FileHeader.NumberOfSections; ++i) {
-        if (strcmp((const char *)section->Name, name) == 0) {
-            return section;
-        }
-        ++section;
-    }
-    return NULL;
-}
-
-void section_boundaries(IMAGE_NT_HEADERS *nt_header, IMAGE_SECTION_HEADER *section, char **start, char **end) {
-    if (section == NULL) {
-        nlr_raise(mp_obj_new_exception_msg(&mp_type_OSError, "Could not lookup section boundaries"));
-    }
-    *start = (char*)(nt_header->OptionalHeader.ImageBase + section->VirtualAddress);
-    *end = *start + section->Misc.VirtualSize;    
-}
-
-void section_boundaries_from_module(const char *module, const char *section, char **start, char **end) {
-    IMAGE_NT_HEADERS *nt_header = header_from_memory(module);
-    IMAGE_SECTION_HEADER *dsection = find_section(nt_header, section);
-    section_boundaries(nt_header, dsection, start, end);   
-}
-
-char *bss_start = 0;
-char *bss_end = 0;
-
-//MSVC has no __bss_start and _end but we can get accurate section info from the PE header.
-//The standard .bss section is appended to the standard .data section however so it cannot
-//be looked up by name. To deal with that we put all uPy static variables in a named section.
-void getbss() {
-    section_boundaries_from_module(NULL, MICROPY_PORT_BSSSECTION, &bss_start, &bss_end);
-}

windows/init.c

@@ -28,12 +28,9 @@
 #include <stdio.h>
 #include <windows.h>
 
-extern void getbss();
-
 HANDLE hSleepEvent = NULL;
 
 void init() {
-    getbss();
     hSleepEvent = CreateEvent(NULL, TRUE, FALSE, FALSE);
 #ifdef __MINGW32__
     putenv("PRINTF_EXPONENT_DIGITS=2");

windows/mpconfigport.h

@@ -166,7 +166,8 @@ void msec_sleep(double msec);
 #define S_ISDIR(m)                  (((m) & S_IFMT) == S_IFDIR)
 
 
-// Put static/global variables in sections with a known name we can lookup for the GC
+// Put static/global variables in sections with a known name
+// This used to be required for GC, not the case anymore but keep it as it makes the map file easier to inspect
 // For this to work this header must be included by all sources, which is the case normally
 #define MICROPY_PORT_DATASECTION "upydata"
 #define MICROPY_PORT_BSSSECTION "upybss"
@@ -183,8 +184,3 @@ void msec_sleep(double msec);
 
 int snprintf(char *dest, size_t count, const char *format, ...);
 #endif
-
-// MingW specifics
-#ifdef __MINGW32__
-#define MICROPY_PORT_BSSSECTION ".bss"
-#endif