Implement EIP-2315: subroutines

packages/common/src/hardforks/berlin.json

@@ -6,7 +6,20 @@
     "status": "Draft"
   },
   "gasConfig": {},
-  "gasPrices": {},
+  "gasPrices": {
+    "beginsub": {
+      "v": 2,
+      "d": "Base fee of the BEGINSUB opcode"
+    },
+    "returnsub": {
+      "v": 5,
+      "d": "Base fee of the RETURNSUB opcode"
+    },
+    "jumpsub": {
+      "v": 10,
+      "d": "Base fee of the JUMPSUB opcode"
+    }
+  },
   "vm": {},
   "pow": {}
 }

packages/vm/lib/evm/interpreter.ts

@@ -20,8 +20,10 @@ export interface RunState {
   memoryWordCount: BN
   highestMemCost: BN
   stack: Stack
+  returnStack: Stack
   code: Buffer
   validJumps: number[]
+  validJumpSubs: number[]
   _common: Common
   stateManager: StateManager
   eei: EEI
@@ -36,6 +38,7 @@ export interface InterpreterStep {
   gasLeft: BN
   stateManager: StateManager
   stack: BN[]
+  returnStack: BN[]
   pc: number
   depth: number
   address: Buffer
@@ -50,6 +53,11 @@ export interface InterpreterStep {
   codeAddress: Buffer
 }
 
+interface JumpDests {
+  jumps: number[]
+  jumpSubs: number[]
+}
+
 /**
  * Parses and executes EVM bytecode.
  */
@@ -70,8 +78,10 @@ export default class Interpreter {
       memoryWordCount: new BN(0),
       highestMemCost: new BN(0),
       stack: new Stack(),
+      returnStack: new Stack(1023), // 1023 return stack height limit per EIP 2315 spec
       code: Buffer.alloc(0),
       validJumps: [],
+      validJumpSubs: [],
       // TODO: Replace with EEI methods
       _common: this._vm._common,
       stateManager: this._state,
@@ -82,7 +92,10 @@ export default class Interpreter {
   async run(code: Buffer, opts: InterpreterOpts = {}): Promise<InterpreterResult> {
     this._runState.code = code
     this._runState.programCounter = opts.pc || this._runState.programCounter
-    this._runState.validJumps = this._getValidJumpDests(code)
+
+    const valid = this._getValidJumpDests(code)
+    this._runState.validJumps = valid.jumps
+    this._runState.validJumpSubs = valid.jumpSubs
 
     // Check that the programCounter is in range
     const pc = this._runState.programCounter
@@ -167,6 +180,7 @@ export default class Interpreter {
         isAsync: opcode.isAsync,
       },
       stack: this._runState.stack._store,
+      returnStack: this._runState.returnStack._store,
       depth: this._eei._env.depth,
       address: this._eei._env.address,
       account: this._eei._env.contract,
@@ -194,9 +208,10 @@ export default class Interpreter {
     return this._vm._emit('step', eventObj)
   }
 
-  // Returns all valid jump destinations.
-  _getValidJumpDests(code: Buffer): number[] {
+  // Returns all valid jump and jumpsub destinations.
+  _getValidJumpDests(code: Buffer): JumpDests {
     const jumps = []
+    const jumpSubs = []
 
     for (let i = 0; i < code.length; i++) {
       const curOpCode = this.lookupOpInfo(code[i]).name
@@ -209,8 +224,12 @@ export default class Interpreter {
       if (curOpCode === 'JUMPDEST') {
         jumps.push(i)
       }
+
+      if (curOpCode === 'BEGINSUB') {
+        jumpSubs.push(i)
+      }
     }
 
-    return jumps
+    return { jumps, jumpSubs }
   }
 }

packages/vm/lib/evm/opFns.ts

@@ -546,6 +546,33 @@ export const handlers: { [k: string]: OpHandler } = {
     runState.stack.push(new BN(runState.eei.getGasLeft()))
   },
   JUMPDEST: function (runState: RunState) {},
+  BEGINSUB: function (runState: RunState) {
+    trap(ERROR.INVALID_BEGINSUB + ' at ' + describeLocation(runState))
+  },
+  JUMPSUB: function (runState: RunState) {
+    const dest = runState.stack.pop()
+
+    if (dest.gt(runState.eei.getCodeSize())) {
+      trap(ERROR.INVALID_JUMPSUB + ' at ' + describeLocation(runState))
+    }
+
+    const destNum = dest.toNumber()
+
+    if (!jumpSubIsValid(runState, destNum)) {
+      trap(ERROR.INVALID_JUMPSUB + ' at ' + describeLocation(runState))
+    }
+
+    runState.returnStack.push(new BN(runState.programCounter))
+    runState.programCounter = destNum + 1
+  },
+  RETURNSUB: function (runState: RunState) {
+    if (runState.returnStack.length < 1) {
+      trap(ERROR.INVALID_RETURNSUB)
+    }
+
+    const dest = runState.returnStack.pop()
+    runState.programCounter = dest.toNumber()
+  },
   PUSH: function (runState: RunState) {
     const numToPush = runState.opCode - 0x5f
     const loaded = new BN(
@@ -927,6 +954,11 @@ function maxCallGas(gasLimit: BN, gasLeft: BN, runState: RunState): BN {
   }
 }
 
+// checks if a jumpsub is valid given a destination
+function jumpSubIsValid(runState: RunState, dest: number): boolean {
+  return runState.validJumpSubs.indexOf(dest) !== -1
+}
+
 async function getContractStorage(runState: RunState, address: Buffer, key: Buffer) {
   const current = await runState.stateManager.getContractStorage(address, key)
   if (

packages/vm/lib/evm/opcodes.ts

@@ -225,6 +225,14 @@ const hardforkOpcodes = [
       0x47: { name: 'SELFBALANCE', isAsync: false }, // EIP 1884
     },
   },
+  {
+    hardforkName: 'berlin',
+    opcodes: {
+      0x5c: { name: 'BEGINSUB', isAsync: false }, // EIP 2315
+      0x5d: { name: 'RETURNSUB', isAsync: false }, // EIP 2315
+      0x5e: { name: 'JUMPSUB', isAsync: false }, // EIP 2315
+    },
+  },
 ]
 
 /**

packages/vm/lib/evm/stack.ts

@@ -7,9 +7,11 @@ const { ERROR, VmError } = require('../exceptions')
  */
 export default class Stack {
   _store: BN[]
+  _maxHeight: number
 
-  constructor() {
+  constructor(maxHeight?: number) {
     this._store = []
+    this._maxHeight = maxHeight || 1024
   }
 
   get length() {
@@ -25,7 +27,7 @@ export default class Stack {
       throw new VmError(ERROR.OUT_OF_RANGE)
     }
 
-    if (this._store.length > 1023) {
+    if (this._store.length >= this._maxHeight) {
       throw new VmError(ERROR.STACK_OVERFLOW)
     }
 

packages/vm/lib/exceptions.ts

@@ -12,6 +12,9 @@ export enum ERROR {
   STOP = 'stop',
   REFUND_EXHAUSTED = 'refund exhausted',
   VALUE_OVERFLOW = 'value overflow',
+  INVALID_BEGINSUB = 'invalid BEGINSUB',
+  INVALID_RETURNSUB = 'invalid RETURNSUB',
+  INVALID_JUMPSUB = 'invalid JUMPSUB',
 }
 
 export class VmError {

packages/vm/lib/index.ts

@@ -118,6 +118,7 @@ export default class VM extends AsyncEventEmitter {
         'petersburg',
         'istanbul',
         'muirGlacier',
+        'berlin',
       ]
 
       this._common = new Common(chain, hardfork, supportedHardforks)

packages/vm/package.json

@@ -68,7 +68,7 @@
     "@types/node": "^11.13.4",
     "@types/tape": "^4.13.0",
     "browserify": "^16.5.1",
-    "ethereumjs-testing": "git+https://github.com/ethereumjs/ethereumjs-testing.git#v1.3.1",
+    "ethereumjs-testing": "git+https://github.com/ethereumjs/ethereumjs-testing.git#v1.3.3",
     "karma": "^4.1.0",
     "karma-browserify": "^6.0.0",
     "karma-chrome-launcher": "^2.2.0",