add sanity check for opcode metadata

Python/compile.c

@@ -8670,6 +8670,27 @@ no_redundant_jumps(cfg_builder *g) {
     return true;
 }
 
+static bool
+opcode_metadata_is_sane(cfg_builder *g) {
+    for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
+        for (int i = 0; i < b->b_iused; i++) {
+            struct instr *instr = &b->b_instr[i];
+            int opcode = instr->i_opcode;
+            assert(opcode <= MAX_REAL_OPCODE); 
+            int pushed = _PyOpcode_opcode_metadata[opcode].n_pushed;
+            int popped = _PyOpcode_opcode_metadata[opcode].n_popped;
+            assert((pushed < 0) == (popped < 0));
+            if (pushed >= 0) {
+                int effect = stack_effect(opcode, instr->i_oparg, -1);
+                if (effect != pushed - popped) {
+                   return false;
+                }
+            }
+        }
+    }
+    return true;
+}
+
 static bool
 no_empty_basic_blocks(cfg_builder *g) {
     for (basicblock *b = g->g_entryblock; b != NULL; b = b->b_next) {
@@ -8853,6 +8874,7 @@ assemble(struct compiler *c, int addNone)
     }
 
     assert(no_redundant_jumps(g));
+    assert(opcode_metadata_is_sane(g));
 
     /* Can't modify the bytecode after computing jump offsets. */
     assemble_jump_offsets(g->g_entryblock);