py: Add MICROPY_PERSISTENT_CODE_LOAD/SAVE to load/save bytecode.

MICROPY_PERSISTENT_CODE must be enabled, and then enabling
MICROPY_PERSISTENT_CODE_LOAD/SAVE (either or both) will allow loading
and/or saving of code (at the moment just bytecode) from/to a .mpy file.

1 files changed, 131 insertions, 0 deletions

diff --git a/py/bc.c b/py/bc.c
index 9f0e79c67..b3d9fca6f 100644
--- a/py/bc.c
+++ b/py/bc.c
@@ -32,6 +32,7 @@
 #include "py/nlr.h"
 #include "py/objfun.h"
 #include "py/runtime0.h"
+#include "py/bc0.h"
 #include "py/bc.h"
 
 #if 0 // print debugging info
@@ -266,3 +267,133 @@ continue2:;
     dump_args(code_state->state + n_state - n_pos_args - n_kwonly_args, n_pos_args + n_kwonly_args);
     dump_args(code_state->state, n_state);
 }
+
+#if MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE
+
+// The following table encodes the number of bytes that a specific opcode
+// takes up.  There are 3 special opcodes that always have an extra byte:
+//     MP_BC_MAKE_CLOSURE
+//     MP_BC_MAKE_CLOSURE_DEFARGS
+//     MP_BC_RAISE_VARARGS
+// There are 4 special opcodes that have an extra byte only when
+// MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE is enabled:
+//     MP_BC_LOAD_NAME
+//     MP_BC_LOAD_GLOBAL
+//     MP_BC_LOAD_ATTR
+//     MP_BC_STORE_ATTR
+#define OC4(a, b, c, d) (a | (b << 2) | (c << 4) | (d << 6))
+#define U (0) // undefined opcode
+#define B (MP_OPCODE_BYTE) // single byte
+#define Q (MP_OPCODE_QSTR) // single byte plus 2-byte qstr
+#define V (MP_OPCODE_VAR_UINT) // single byte plus variable encoded unsigned int
+#define O (MP_OPCODE_OFFSET) // single byte plus 2-byte bytecode offset
+STATIC const byte opcode_format_table[64] = {
+    OC4(U, U, U, U), // 0x00-0x03
+    OC4(U, U, U, U), // 0x04-0x07
+    OC4(U, U, U, U), // 0x08-0x0b
+    OC4(U, U, U, U), // 0x0c-0x0f
+    OC4(B, B, B, U), // 0x10-0x13
+    OC4(V, U, Q, V), // 0x14-0x17
+    OC4(B, U, V, V), // 0x18-0x1b
+    OC4(Q, Q, Q, Q), // 0x1c-0x1f
+    OC4(B, B, V, V), // 0x20-0x23
+    OC4(Q, Q, Q, B), // 0x24-0x27
+    OC4(V, V, Q, Q), // 0x28-0x2b
+    OC4(U, U, U, U), // 0x2c-0x2f
+    OC4(B, B, B, B), // 0x30-0x33
+    OC4(B, O, O, O), // 0x34-0x37
+    OC4(O, O, U, U), // 0x38-0x3b
+    OC4(U, O, B, O), // 0x3c-0x3f
+    OC4(O, B, B, O), // 0x40-0x43
+    OC4(B, B, O, B), // 0x44-0x47
+    OC4(U, U, U, U), // 0x48-0x4b
+    OC4(U, U, U, U), // 0x4c-0x4f
+    OC4(V, V, V, V), // 0x50-0x53
+    OC4(B, V, V, V), // 0x54-0x57
+    OC4(V, V, V, B), // 0x58-0x5b
+    OC4(B, B, B, U), // 0x5c-0x5f
+    OC4(V, V, V, V), // 0x60-0x63
+    OC4(V, V, V, V), // 0x64-0x67
+    OC4(Q, Q, B, U), // 0x68-0x6b
+    OC4(U, U, U, U), // 0x6c-0x6f
+
+    OC4(B, B, B, B), // 0x70-0x73
+    OC4(B, B, B, B), // 0x74-0x77
+    OC4(B, B, B, B), // 0x78-0x7b
+    OC4(B, B, B, B), // 0x7c-0x7f
+    OC4(B, B, B, B), // 0x80-0x83
+    OC4(B, B, B, B), // 0x84-0x87
+    OC4(B, B, B, B), // 0x88-0x8b
+    OC4(B, B, B, B), // 0x8c-0x8f
+    OC4(B, B, B, B), // 0x90-0x93
+    OC4(B, B, B, B), // 0x94-0x97
+    OC4(B, B, B, B), // 0x98-0x9b
+    OC4(B, B, B, B), // 0x9c-0x9f
+    OC4(B, B, B, B), // 0xa0-0xa3
+    OC4(B, B, B, B), // 0xa4-0xa7
+    OC4(B, B, B, B), // 0xa8-0xab
+    OC4(B, B, B, B), // 0xac-0xaf
+
+    OC4(B, B, B, B), // 0xb0-0xb3
+    OC4(B, B, B, B), // 0xb4-0xb7
+    OC4(B, B, B, B), // 0xb8-0xbb
+    OC4(B, B, B, B), // 0xbc-0xbf
+
+    OC4(B, B, B, B), // 0xc0-0xc3
+    OC4(B, B, B, B), // 0xc4-0xc7
+    OC4(B, B, B, B), // 0xc8-0xcb
+    OC4(B, B, B, B), // 0xcc-0xcf
+
+    OC4(B, B, B, B), // 0xd0-0xd3
+    OC4(B, B, B, B), // 0xd4-0xd7
+    OC4(B, B, B, B), // 0xd8-0xdb
+    OC4(B, B, B, B), // 0xdc-0xdf
+
+    OC4(B, B, B, B), // 0xe0-0xe3
+    OC4(B, B, B, B), // 0xe4-0xe7
+    OC4(B, B, B, B), // 0xe8-0xeb
+    OC4(B, B, B, B), // 0xec-0xef
+
+    OC4(B, B, B, B), // 0xf0-0xf3
+    OC4(B, B, B, B), // 0xf4-0xf7
+    OC4(B, B, U, U), // 0xf8-0xfb
+    OC4(U, U, U, U), // 0xfc-0xff
+};
+#undef OC4
+#undef U
+#undef B
+#undef Q
+#undef V
+#undef O
+
+uint mp_opcode_format(const byte *ip, size_t *opcode_size) {
+    uint f = (opcode_format_table[*ip >> 2] >> (2 * (*ip & 3))) & 3;
+    const byte *ip_start = ip;
+    if (f == MP_OPCODE_QSTR) {
+        ip += 3;
+    } else {
+        int extra_byte = (
+            *ip == MP_BC_RAISE_VARARGS
+            || *ip == MP_BC_MAKE_CLOSURE
+            || *ip == MP_BC_MAKE_CLOSURE_DEFARGS
+            #if MICROPY_OPT_CACHE_MAP_LOOKUP_IN_BYTECODE
+            || *ip == MP_BC_LOAD_NAME
+            || *ip == MP_BC_LOAD_GLOBAL
+            || *ip == MP_BC_LOAD_ATTR
+            || *ip == MP_BC_STORE_ATTR
+            #endif
+        );
+        ip += 1;
+        if (f == MP_OPCODE_VAR_UINT) {
+            while ((*ip++ & 0x80) != 0) {
+            }
+        } else if (f == MP_OPCODE_OFFSET) {
+            ip += 2;
+        }
+        ip += extra_byte;
+    }
+    *opcode_size = ip - ip_start;
+    return f;
+}
+
+#endif // MICROPY_PERSISTENT_CODE_LOAD || MICROPY_PERSISTENT_CODE_SAVE