core/vm: EIP-2315, JUMPSUB for the EVM (#20619)

* core/vm: implement EIP 2315, subroutines for the EVM

* core/vm: eip 2315 - lintfix + check jump dest validity + check ret stack size constraints

  logger: markdown-friendly traces, validate jumpdest, more testcase, correct opcodes

* core/vm: update subroutines acc to eip: disallow walk-into

* core/vm/eips: gas cost changes for subroutines

* core/vm: update opcodes for EIP-2315

* core/vm: define RETURNSUB as a 'jumping' operation + review concerns

Co-authored-by: Martin Holst Swende <martin@swende.se>

core/vm/instructions.go

@@ -664,6 +664,39 @@ func opJumpdest(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) (
 	return nil, nil
 }
 
+func opBeginSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	return nil, ErrInvalidSubroutineEntry
+}
+
+func opJumpSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	if len(callContext.rstack.data) >= 1023 {
+		return nil, ErrReturnStackExceeded
+	}
+	pos := callContext.stack.pop()
+	if !pos.IsUint64() {
+		return nil, ErrInvalidJump
+	}
+	posU64 := pos.Uint64()
+	if !callContext.contract.validJumpSubdest(posU64) {
+		return nil, ErrInvalidJump
+	}
+	callContext.rstack.push(*pc)
+	*pc = posU64 + 1
+	interpreter.intPool.put(pos)
+	return nil, nil
+}
+
+func opReturnSub(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
+	if len(callContext.rstack.data) == 0 {
+		return nil, ErrInvalidRetsub
+	}
+	// Other than the check that the return stack is not empty, there is no
+	// need to validate the pc from 'returns', since we only ever push valid
+	//values onto it via jumpsub.
+	*pc = callContext.rstack.pop() + 1
+	return nil, nil
+}
+
 func opPc(pc *uint64, interpreter *EVMInterpreter, callContext *callCtx) ([]byte, error) {
 	callContext.stack.push(interpreter.intPool.get().SetUint64(*pc))
 	return nil, nil