Remove unnecesary memory checks

lambdaclass · Sep 13, 2024 · f5dae8e · f5dae8e
1 parent f17241f
commit f5dae8e
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Showing 2 changed files with 12 additions and 6 deletions.
diff --git a/system-contracts/contracts/EvmInterpreter.yul b/system-contracts/contracts/EvmInterpreter.yul
@@ -2966,7 +2966,8 @@ object "EVMInterpreter" {
                     evmGasLeft := chargeGas(evmGasLeft,expandMemory(add(offset,size)))
 
                     returnLen := size
-                    checkOverflow(offset,MEM_OFFSET_INNER(), evmGasLeft)
+
+                    // Don't check overflow here since previous checks are enough to ensure this is safe
                     returnOffset := add(MEM_OFFSET_INNER(), offset)
                     break
                 }
@@ -3006,7 +3007,8 @@ object "EVMInterpreter" {
                     checkMemOverflowByOffset(add(offset, size), evmGasLeft)
                     evmGasLeft := chargeGas(evmGasLeft,expandMemory(add(offset,size)))
 
-                    checkOverflow(offset,MEM_OFFSET_INNER(), evmGasLeft)
+
+                    // Don't check overflow here since previous checks are enough to ensure this is safe
                     offset := add(offset, MEM_OFFSET_INNER())
                     offset,size := addGasIfEvmRevert(isCallerEVM,offset,size,evmGasLeft)
 
@@ -5940,7 +5942,8 @@ object "EVMInterpreter" {
                         evmGasLeft := chargeGas(evmGasLeft,expandMemory(add(offset,size)))
 
                         returnLen := size
-                        checkOverflow(offset,MEM_OFFSET_INNER(), evmGasLeft)
+
+                        // Don't check overflow here since previous checks are enough to ensure this is safe
                         returnOffset := add(MEM_OFFSET_INNER(), offset)
                         break
                     }
@@ -5980,7 +5983,8 @@ object "EVMInterpreter" {
                         checkMemOverflowByOffset(add(offset, size), evmGasLeft)
                         evmGasLeft := chargeGas(evmGasLeft,expandMemory(add(offset,size)))
 
-                        checkOverflow(offset,MEM_OFFSET_INNER(), evmGasLeft)
+
+                        // Don't check overflow here since previous checks are enough to ensure this is safe
                         offset := add(offset, MEM_OFFSET_INNER())
                         offset,size := addGasIfEvmRevert(isCallerEVM,offset,size,evmGasLeft)
 

diff --git a/system-contracts/evm-interpreter/EvmInterpreterLoop.template.yul b/system-contracts/evm-interpreter/EvmInterpreterLoop.template.yul
@@ -1406,7 +1406,8 @@ for { } true { } {
         evmGasLeft := chargeGas(evmGasLeft,expandMemory(add(offset,size)))
 
         returnLen := size
-        checkOverflow(offset,MEM_OFFSET_INNER(), evmGasLeft)
+
+        // Don't check overflow here since previous checks are enough to ensure this is safe
         returnOffset := add(MEM_OFFSET_INNER(), offset)
         break
     }
@@ -1446,7 +1447,8 @@ for { } true { } {
         checkMemOverflowByOffset(add(offset, size), evmGasLeft)
         evmGasLeft := chargeGas(evmGasLeft,expandMemory(add(offset,size)))
 
-        checkOverflow(offset,MEM_OFFSET_INNER(), evmGasLeft)
+
+        // Don't check overflow here since previous checks are enough to ensure this is safe
         offset := add(offset, MEM_OFFSET_INNER())
         offset,size := addGasIfEvmRevert(isCallerEVM,offset,size,evmGasLeft)