Increment free memory pointer for internal Exchange functions that use asm

3 files changed, 34 insertions, 12 deletions

diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
index e9f882194..b34903668 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -159,18 +159,22 @@ contract MixinAssetProxyDispatcher is
                 }
 
                 /////// Call `assetProxy.transferFrom` using the constructed calldata ///////
+                let inputLen := sub(cdEnd, cdStart)
                 let success := call(
                     gas,                    // forward all gas
                     assetProxy,             // call address of asset proxy
                     0,                      // don't send any ETH
                     cdStart,                // pointer to start of input
-                    sub(cdEnd, cdStart),    // length of input  
+                    inputLen,               // length of input  
                     cdStart,                // write output over input
                     512                     // reserve 512 bytes for output
                 )
                 if iszero(success) {
                     revert(cdStart, returndatasize())
                 }
+
+                // Increment free memory pointer
+                mstore(64, add(cdStart, inputLen))
             }
         }
     }
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibAbiEncoder.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibAbiEncoder.sol
index 704c7061c..f047342b3 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibAbiEncoder.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibAbiEncoder.sol
@@ -24,20 +24,17 @@ import "./LibOrder.sol";
 
 contract LibAbiEncoder {
 
-    /// @dev ABI encodes calldata for `fillOrder` in memory and returns the address range.
-    ///      This range can be passed into `call` or `delegatecall` to invoke an external
-    ///      call to `fillOrder`.
+    /// @dev ABI encodes calldata for `fillOrder`.
     /// @param order Order struct containing order specifications.
     /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
     /// @param signature Proof that order has been created by maker.
-    /// @return calldataBegin Memory address of ABI encoded calldata.
-    /// @return calldataLength Lenfgth of ABI encoded calldata.
+    /// @return ABI encoded calldata for `fillOrder`.
     function abiEncodeFillOrder(
         LibOrder.Order memory order,
         uint256 takerAssetFillAmount,
         bytes memory signature
     )
-        public
+        internal
         pure
         returns (bytes memory fillOrderCalldata)
     {
@@ -207,10 +204,11 @@ contract LibAbiEncoder {
             }
 
             // Set length of calldata
-            mstore(
-                fillOrderCalldata,
-                sub(dataAreaEnd, add(fillOrderCalldata, 0x20))
-            )
+            let calldataLen := sub(dataAreaEnd, add(fillOrderCalldata, 0x20))
+            mstore(fillOrderCalldata, calldataLen)
+
+            // Increment free memory pointer
+            mstore(0x40, add(fillOrderCalldata, add(calldataLen, 0x20)))
         }
 
         return fillOrderCalldata;
diff --git a/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
index 5a349527b..4a99dd9c1 100644
--- a/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
+++ b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
@@ -22,13 +22,33 @@ pragma experimental ABIEncoderV2;
 import "../../protocol/Exchange/libs/LibMath.sol";
 import "../../protocol/Exchange/libs/LibOrder.sol";
 import "../../protocol/Exchange/libs/LibFillResults.sol";
+import "../../protocol/Exchange/libs/LibAbiEncoder.sol";
 
 
 contract TestLibs is 
     LibMath,
     LibOrder,
-    LibFillResults
+    LibFillResults,
+    LibAbiEncoder
 {
+
+    function publicAbiEncodeFillOrder(
+        Order memory order,
+        uint256 takerAssetFillAmount,
+        bytes memory signature
+    )
+        public
+        pure
+        returns (bytes memory fillOrderCalldata)
+    {
+        fillOrderCalldata = abiEncodeFillOrder(
+            order,
+            takerAssetFillAmount,
+            signature
+        );
+        return fillOrderCalldata;
+    }
+
     function publicGetPartialAmount(
         uint256 numerator,
         uint256 denominator,