py/emitglue: Add feature-flag header to .mpy to detect bytecode compat.

dpgeorge · dpgeorge · commit 39a8deb95f90 · 2015-11-23T10:58:16.000Z
Loading .mpy files will now check to make sure that the target VM can
support the bytecode.
diff --git a/py/emitglue.c b/py/emitglue.c
@@ -319,12 +319,16 @@ STATIC mp_raw_code_t *load_raw_code(mp_reader_t *reader) {
 }
 
 mp_raw_code_t *mp_raw_code_load(mp_reader_t *reader) {
-    byte header[2];
-    read_bytes(reader, header, 2);
+    byte header[3];
+    read_bytes(reader, header, 3);
     if (strncmp((char*)header, "M\x00", 2) != 0) {
         nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
             "invalid .mpy file"));
     }
+    if (header[2] != MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE) {
+        nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,
+            "incompatible .mpy file"));
+    }
     return load_raw_code(reader);
 }
 
@@ -558,7 +562,13 @@ STATIC void save_raw_code(mp_print_t *print, mp_raw_code_t *rc) {
 }
 
 void mp_raw_code_save(mp_raw_code_t *rc, mp_print_t *print) {
-    mp_print_bytes(print, (const byte*)"M\x00", 2);
+    // header contains:
+    //  byte  'M'
+    //  byte  version
+    //  byte  feature flags (right now just OPT_CACHE_MAP_LOOKUP_IN_BYTECODE)
+    byte header[3] = {'M', 0, MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE};
+    mp_print_bytes(print, header, 3);
+
     save_raw_code(print, rc);
 }
 

Original file line number	Diff line number	Diff line change
`@@ -319,12 +319,16 @@ STATIC mp_raw_code_t load_raw_code(mp_reader_t reader) {`
`319`	`319`	`}`
`320`	`320`
`321`	`321`	`mp_raw_code_t mp_raw_code_load(mp_reader_t reader) {`
`322`		`- byte header[2];`
`323`		`- read_bytes(reader, header, 2);`
	`322`	`+ byte header[3];`
	`323`	`+ read_bytes(reader, header, 3);`
`324`	`324`	`if (strncmp((char*)header, "M\x00", 2) != 0) {`
`325`	`325`	`nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,`
`326`	`326`	`"invalid .mpy file"));`
`327`	`327`	`}`
	`328`	`+ if (header[2] != MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE) {`
	`329`	`+ nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError,`
	`330`	`+ "incompatible .mpy file"));`
	`331`	`+ }`
`328`	`332`	`return load_raw_code(reader);`
`329`	`333`	`}`
`330`	`334`
`@@ -558,7 +562,13 @@ STATIC void save_raw_code(mp_print_t print, mp_raw_code_t rc) {`
`558`	`562`	`}`
`559`	`563`
`560`	`564`	`void mp_raw_code_save(mp_raw_code_t rc, mp_print_t print) {`
`561`		`- mp_print_bytes(print, (const byte*)"M\x00", 2);`
	`565`	`+ // header contains:`
	`566`	`+ // byte 'M'`
	`567`	`+ // byte version`
	`568`	`+ // byte feature flags (right now just OPT_CACHE_MAP_LOOKUP_IN_BYTECODE)`
	`569`	`+ byte header[3] = {'M', 0, MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE};`
	`570`	`+ mp_print_bytes(print, header, 3);`
	`571`	`+`
`562`	`572`	`save_raw_code(print, rc);`
`563`	`573`	`}`
`564`	`574`