py: Reorganise bytecode layout so it's more structured, easier to edit.

1 files changed, 18 insertions, 12 deletions

diff --git a/py/showbc.c b/py/showbc.c
index 2da8d3feb..87e7c6af4 100644
--- a/py/showbc.c
+++ b/py/showbc.c
@@ -57,7 +57,16 @@ const byte *mp_showbc_code_start;
 void mp_bytecode_print(const void *descr, mp_uint_t n_total_args, const byte *ip, mp_uint_t len) {
     mp_showbc_code_start = ip;
 
-    // get code info size
+    // get state size and exception stack size
+    mp_uint_t n_state = mp_decode_uint(&ip);
+    mp_uint_t n_exc_stack = mp_decode_uint(&ip);
+
+    ip = MP_ALIGN(ip, sizeof(mp_uint_t));
+
+    // get and skip arg names
+    const mp_obj_t *arg_names = (const mp_obj_t*)ip;
+    ip += n_total_args * sizeof(mp_uint_t);
+
     const byte *code_info = ip;
     mp_uint_t code_info_size = mp_decode_uint(&code_info);
     ip += code_info_size;
@@ -65,7 +74,7 @@ void mp_bytecode_print(const void *descr, mp_uint_t n_total_args, const byte *ip
     qstr block_name = mp_decode_uint(&code_info);
     qstr source_file = mp_decode_uint(&code_info);
     printf("File %s, code block '%s' (descriptor: %p, bytecode @%p " UINT_FMT " bytes)\n",
-        qstr_str(source_file), qstr_str(block_name), descr, code_info, len);
+        qstr_str(source_file), qstr_str(block_name), descr, mp_showbc_code_start, len);
 
     // raw bytecode dump
     printf("Raw bytecode (code_info_size=" UINT_FMT ", bytecode_size=" UINT_FMT "):\n", code_info_size, len - code_info_size);
@@ -80,18 +89,15 @@ void mp_bytecode_print(const void *descr, mp_uint_t n_total_args, const byte *ip
     // bytecode prelude: arg names (as qstr objects)
     printf("arg names:");
     for (mp_uint_t i = 0; i < n_total_args; i++) {
-        printf(" %s", qstr_str(MP_OBJ_QSTR_VALUE(*(mp_obj_t*)ip)));
-        ip += sizeof(mp_obj_t);
+        printf(" %s", qstr_str(MP_OBJ_QSTR_VALUE(arg_names[i])));
     }
     printf("\n");
 
-    // bytecode prelude: state size and exception stack size; 16 bit uints
-    {
-        uint n_state = mp_decode_uint(&ip);
-        uint n_exc_stack = mp_decode_uint(&ip);
-        printf("(N_STATE %u)\n", n_state);
-        printf("(N_EXC_STACK %u)\n", n_exc_stack);
-    }
+    printf("(N_STATE " UINT_FMT ")\n", n_state);
+    printf("(N_EXC_STACK " UINT_FMT ")\n", n_exc_stack);
+
+    // for printing line number info
+    const byte *bytecode_start = ip;
 
     // bytecode prelude: initialise closed over variables
     {
@@ -104,7 +110,7 @@ void mp_bytecode_print(const void *descr, mp_uint_t n_total_args, const byte *ip
 
     // print out line number info
     {
-        mp_int_t bc = (mp_showbc_code_start + code_info_size) - ip; // start counting from the prelude
+        mp_int_t bc = bytecode_start - ip;
         mp_uint_t source_line = 1;
         printf("  bc=" INT_FMT " line=" UINT_FMT "\n", bc, source_line);
         for (const byte* ci = code_info; *ci;) {