py/emitglue: Provide a truncated mp_raw_code_t for non-asm code.

The `asm_n_pos_args` and `asm_type_sig` members of `mp_raw_code_t` are only
used for raw codes of type MP_CODE_NATIVE_ASM, which are rare, for example
in frozen code.  So using a truncated `mp_raw_code_t` in these cases helps
to reduce frozen code size on targets that have MICROPY_EMIT_INLINE_ASM
enabled.

With this, change in firmware size of RPI_PICO builds is -648.

Signed-off-by: Damien George <damien@micropython.org>

py/dynruntime.h

@@ -207,7 +207,7 @@ static inline void *mp_obj_malloc_helper_dyn(size_t num_bytes, const mp_obj_type
 
 #define MP_DYNRUNTIME_INIT_ENTRY \
     mp_obj_t old_globals = mp_fun_table.swap_globals(self->context->module.globals); \
-    mp_raw_code_t rc; \
+    mp_raw_code_truncated_t rc; \
     rc.kind = MP_CODE_NATIVE_VIPER; \
     rc.scope_flags = 0; \
     (void)rc;
@@ -217,7 +217,7 @@ static inline void *mp_obj_malloc_helper_dyn(size_t num_bytes, const mp_obj_type
     return mp_const_none;
 
 #define MP_DYNRUNTIME_MAKE_FUNCTION(f) \
-    (mp_make_function_from_raw_code((rc.fun_data = (f), &rc), self->context, NULL))
+    (mp_make_function_from_raw_code((rc.fun_data = (f), (const mp_raw_code_t *)&rc), self->context, NULL))
 
 #define mp_import_name(name, fromlist, level) \
     (mp_fun_table.import_name((name), (fromlist), (level)))

py/emitglue.h

@@ -84,6 +84,29 @@ typedef struct _mp_raw_code_t {
     #endif
 } mp_raw_code_t;
 
+// Version of mp_raw_code_t but without the asm_n_pos_args/asm_type_sig entries, which are
+// only needed when the kind is MP_CODE_NATIVE_ASM.  So this struct can be used when the
+// kind is MP_CODE_BYTECODE, MP_CODE_NATIVE_PY or MP_CODE_NATIVE_VIPER, to reduce its size.
+typedef struct _mp_raw_code_truncated_t {
+    uint32_t kind : 3;
+    uint32_t scope_flags : 7;
+    const void *fun_data;
+    struct _mp_raw_code_t **children;
+    #if MICROPY_PERSISTENT_CODE_SAVE || MICROPY_DEBUG_PRINTERS
+    uint32_t fun_data_len;
+    #endif
+    #if MICROPY_PERSISTENT_CODE_SAVE
+    uint16_t n_children;
+    #if MICROPY_EMIT_MACHINE_CODE
+    uint16_t prelude_offset;
+    #endif
+    #if MICROPY_PY_SYS_SETTRACE
+    uint32_t line_of_definition;
+    mp_bytecode_prelude_t prelude;
+    #endif
+    #endif
+} mp_raw_code_truncated_t;
+
 mp_raw_code_t *mp_emit_glue_new_raw_code(void);
 
 void mp_emit_glue_assign_bytecode(mp_raw_code_t *rc, const byte *code,

tools/mpy-tool.py

@@ -683,7 +683,7 @@ class CompiledModule:
         else:
             print("        .obj_table = NULL,")
         print("    },")
-        print("    .rc = &raw_code_%s," % self.raw_code.escaped_name)
+        print("    .rc = (const mp_raw_code_t *)&raw_code_%s," % self.raw_code.escaped_name)
         print("};")
 
     def freeze_constant_obj(self, obj_name, obj):
@@ -898,7 +898,7 @@ class RawCode(object):
                 print()
             print("static const mp_raw_code_t *const children_%s[] = {" % self.escaped_name)
             for rc in self.children:
-                print("    &raw_code_%s," % rc.escaped_name)
+                print("    (const mp_raw_code_t *)&raw_code_%s," % rc.escaped_name)
             if prelude_ptr:
                 print("    (void *)%s," % prelude_ptr)
             print("};")
@@ -906,7 +906,11 @@ class RawCode(object):
 
     def freeze_raw_code(self, prelude_ptr=None, type_sig=0):
         # Generate mp_raw_code_t.
-        print("static const mp_raw_code_t raw_code_%s = {" % self.escaped_name)
+        if self.code_kind == MP_CODE_NATIVE_ASM:
+            raw_code_type = "mp_raw_code_t"
+        else:
+            raw_code_type = "mp_raw_code_truncated_t"
+        print("static const %s raw_code_%s = {" % (raw_code_type, self.escaped_name))
         print("    .kind = %s," % RawCode.code_kind_str[self.code_kind])
         print("    .scope_flags = 0x%02x," % self.scope_flags)
         print("    .fun_data = fun_data_%s," % self.escaped_name)
@@ -949,10 +953,9 @@ class RawCode(object):
             print("    },")
             print("    #endif")
         print("    #endif")
-        print("    #if MICROPY_EMIT_INLINE_ASM")
-        print("    .asm_n_pos_args = %u," % self.n_pos_args)
-        print("    .asm_type_sig = %u," % type_sig)
-        print("    #endif")
+        if self.code_kind == MP_CODE_NATIVE_ASM:
+            print("    .asm_n_pos_args = %u," % self.n_pos_args)
+            print("    .asm_type_sig = %u," % type_sig)
         print("};")
 
         global raw_code_count, raw_code_content