Remove no-op OP_swap+OP_swap bytecode sequence

[bnoordhuis]

Observed in generated code for static initializers. We could in theory track and correct it in js_parse_class() but doing it as a peephole optimization is both easier and more general.

[saghul]

Out of curiosity how are you digging these things up?

[bnoordhuis]

puts() and patience basically :-)

diff --git a/quickjs.c b/quickjs.c
index e9f5197..e9cd759 100644
--- a/quickjs.c
+++ b/quickjs.c
@@ -14170,7 +14170,12 @@ static JSValue JS_CallInternal(JSContext *caller_ctx, JSValueConst func_obj,
 #include "quickjs-opcode.h"
         [ OP_COUNT ... 255 ] = &&case_default
     };
-#define SWITCH(pc)      goto *dispatch_table[opcode = *pc++];
+    static const char * const opnames[] = {
+#undef DEF
+#define DEF(id, size, n_pop, n_push, f) #id,
+#include "quickjs-opcode.h"
+    };
+#define SWITCH(pc)      puts(opnames[*pc]); goto *dispatch_table[opcode = *pc++];
 #define CASE(op)        case_ ## op
 #define DEFAULT         case_default
 #define BREAK           SWITCH(pc)