Merge pull request #11268 from ethereum/refactorByteArrayPopSol2Yul

[Sol->Yul] Refactor ByteArrayPop to use unchecked index access

libsolidity/codegen/YulUtilFunctions.cpp

@@ -1348,6 +1348,24 @@ string YulUtilFunctions::shortByteArrayEncodeUsedAreaSetLengthFunction()
 	});
 }
 
+string YulUtilFunctions::longByteArrayStorageIndexAccessNoCheckFunction()
+{
+	return m_functionCollector.createFunction(
+		"long_byte_array_index_access_no_checks",
+		[&](vector<string>& _args, vector<string>& _returnParams) {
+			_args = {"array", "index"};
+			_returnParams = {"slot", "offset"};
+			return Whiskers(R"(
+				offset := sub(31, mod(index, 0x20))
+				let dataArea := <dataAreaFunc>(array)
+				slot := add(dataArea, div(index, 0x20))
+			)")
+			("dataAreaFunc", arrayDataAreaFunction(*TypeProvider::bytesStorage()))
+			.render();
+		}
+	);
+}
+
 string YulUtilFunctions::storageArrayPopFunction(ArrayType const& _type)
 {
 	solAssert(_type.location() == DataLocation::Storage, "");
@@ -1406,7 +1424,7 @@ string YulUtilFunctions::storageByteArrayPopFunction(ArrayType const& _type)
 						sstore(array, <encodeUsedSetLen>(data, newLen))
 					}
 					default {
-						let slot, offset := <indexAccess>(array, newLen)
+						let slot, offset := <indexAccessNoChecks>(array, newLen)
 						<setToZero>(slot, offset)
 						sstore(array, sub(data, 2))
 					}
@@ -1417,7 +1435,7 @@ string YulUtilFunctions::storageByteArrayPopFunction(ArrayType const& _type)
 			("extractByteArrayLength", extractByteArrayLengthFunction())
 			("transitLongToShort", byteArrayTransitLongToShortFunction(_type))
 			("encodeUsedSetLen", shortByteArrayEncodeUsedAreaSetLengthFunction())
-			("indexAccess", storageArrayIndexAccessFunction(_type))
+			("indexAccessNoChecks", longByteArrayStorageIndexAccessNoCheckFunction())
 			("setToZero", storageSetToZeroFunction(*_type.baseType()))
 			.render();
 	});
@@ -2112,13 +2130,12 @@ string YulUtilFunctions::storageArrayIndexAccessFunction(ArrayType const& _type)
 
 				<?multipleItemsPerSlot>
 					<?isBytesArray>
-						offset := sub(31, mod(index, 0x20))
 						switch lt(arrayLength, 0x20)
 						case 0 {
-							let dataArea := <dataAreaFunc>(array)
+							slot, offset := <indexAccessNoChecks>(array, index)
-							slot := add(dataArea, div(index, 0x20))
 						}
 						default {
+							offset := sub(31, mod(index, 0x20))
 							slot := array
 						}
 					<!isBytesArray>
@@ -2137,6 +2154,7 @@ string YulUtilFunctions::storageArrayIndexAccessFunction(ArrayType const& _type)
 		("panic", panicFunction(PanicCode::ArrayOutOfBounds))
 		("arrayLen", arrayLengthFunction(_type))
 		("dataAreaFunc", arrayDataAreaFunction(_type))
+		("indexAccessNoChecks", longByteArrayStorageIndexAccessNoCheckFunction())
 		("multipleItemsPerSlot", _type.baseType()->storageBytes() <= 16)
 		("isBytesArray", _type.isByteArray())
 		("storageSize", _type.baseType()->storageSize().str())

libsolidity/codegen/YulUtilFunctions.h

@@ -552,6 +552,11 @@ private:
 	/// signature: (data, len) -> data
 	std::string shortByteArrayEncodeUsedAreaSetLengthFunction();
 
+	/// @returns the name of a function that calculates slot and offset for index
+	/// Doesn't perform length checks, assumes that index is in bounds
+	/// signature: (array, index)
+	std::string longByteArrayStorageIndexAccessNoCheckFunction();
+
 	langutil::EVMVersion m_evmVersion;
 	RevertStrings m_revertStrings;
 	MultiUseYulFunctionCollector& m_functionCollector;

test/cmdlineTests/name_simplifier/output

@@ -139,14 +139,14 @@ object "C_59" {
             }
             function storage_array_index_access_struct_S_1252() -> slot, offset
             {
-                if iszero(lt(slot, 0x02)) { panic_error_0x32() }
+                if iszero(lt(offset, 0x02)) { panic_error_0x32() }
-                slot := add(slot, slot)
+                slot := add(offset, offset)
                 offset := offset
             }
             function storage_array_index_access_struct_S() -> slot, offset
             {
-                if iszero(lt(slot, 0x02)) { panic_error_0x32() }
+                if iszero(lt(offset, 0x02)) { panic_error_0x32() }
-                slot := add(0x02, slot)
+                slot := add(0x02, offset)
                 offset := offset
             }
         }

test/libsolidity/semanticTests/array/byte_array_transitional_2.sol

@@ -19,6 +19,6 @@ contract c {
 // compileViaYul: also
 // ----
 // test() -> 0
-// gas irOptimized: 311472
+// gas irOptimized: 310460
 // gas legacy: 483915
 // gas legacyOptimized: 478672

test/libsolidity/semanticTests/array/dynamic_arrays_in_storage.sol

@@ -44,7 +44,7 @@ contract c {
 // ----
 // getLengths() -> 0, 0
 // setLengths(uint256,uint256): 48, 49 ->
-// gas irOptimized: 275838
+// gas irOptimized: 276212
 // gas legacy: 308271
 // gas legacyOptimized: 300117
 // getLengths() -> 48, 49

test/libsolidity/semanticTests/array/pop/byte_array_pop_copy_long.sol

@@ -12,6 +12,6 @@ contract c {
 // compileViaYul: also
 // ----
 // test() -> 0x20, 29, 0x0303030303030303030303030303030303030303030303030303030303000000
-// gas irOptimized: 163572
+// gas irOptimized: 162649
 // gas legacy: 245809
 // gas legacyOptimized: 242636

test/libsolidity/semanticTests/array/pop/byte_array_pop_long_storage_empty.sol

@@ -18,7 +18,7 @@ contract c {
 // compileViaYul: also
 // ----
 // test() -> true
-// gas irOptimized: 455893
+// gas irOptimized: 447028
 // gas legacy: 552064
 // gas legacyOptimized: 533164
 // storage: empty

test/libsolidity/semanticTests/array/pop/byte_array_pop_long_storage_empty_garbage_ref.sol

@@ -17,7 +17,7 @@ contract c {
 // compileViaYul: also
 // ----
 // test() ->
-// gas irOptimized: 300849
+// gas irOptimized: 291984
 // gas legacy: 372763
 // gas legacyOptimized: 366846
 // storage: empty

test/libsolidity/semanticTests/array/pop/byte_array_pop_masking_long.sol

@@ -12,6 +12,6 @@ contract c {
 // compileViaYul: also
 // ----
 // test() -> 0x20, 33, 0x303030303030303030303030303030303030303030303030303030303030303, 0x0300000000000000000000000000000000000000000000000000000000000000
-// gas irOptimized: 160904
+// gas irOptimized: 160043
 // gas legacy: 243287
 // gas legacyOptimized: 240361

test/libsolidity/semanticTests/array/push/push_no_args_bytes.sol

@@ -23,7 +23,7 @@ contract C {
 // ----
 // l() -> 0
 // g(uint256): 70 ->
-// gas irOptimized: 428769
+// gas irOptimized: 429679
 // gas legacy: 419791
 // gas legacyOptimized: 415408
 // l() -> 70

test/libsolidity/semanticTests/constructor/bytes_in_constructors_packer.sol

@@ -26,6 +26,6 @@ contract Creator {
 // compileViaYul: also
 // ----
 // f(uint256,bytes): 7, 0x40, 78, "abcdefghijklmnopqrstuvwxyzabcdef", "ghijklmnopqrstuvwxyzabcdefghijkl", "mnopqrstuvwxyz" -> 7, "h"
-// gas irOptimized: 323391
+// gas irOptimized: 322968
 // gas legacy: 414850
 // gas legacyOptimized: 290278