Merge pull request #9503 from ethereum/copyStructCalldataMemorySol2Yul

[Sol->Yul] Implementing struct copying from calldata to memory.

libsolidity/codegen/YulUtilFunctions.cpp

@@ -1911,8 +1911,23 @@ string YulUtilFunctions::conversionFunction(Type const& _from, Type const& _to)
 			break;
 		}
 		case Type::Category::Struct:
-			solUnimplementedAssert(false, "Struct conversion not implemented.");
+		{
+			solAssert(toCategory == Type::Category::Struct, "");
+			auto const& fromStructType = dynamic_cast<StructType const &>(_from);
+			auto const& toStructType = dynamic_cast<StructType const &>(_to);
+			solAssert(fromStructType.structDefinition() == toStructType.structDefinition(), "");
+
+			solUnimplementedAssert(!fromStructType.isDynamicallyEncoded(), "");
+			solUnimplementedAssert(toStructType.location() == DataLocation::Memory, "");
+			solUnimplementedAssert(fromStructType.location() == DataLocation::CallData, "");
+
+			body = Whiskers(R"(
+				converted := <abiDecode>(value, calldatasize())
+			)")("abiDecode", ABIFunctions(m_evmVersion, m_revertStrings, m_functionCollector).tupleDecoder(
+				{&toStructType}
+			)).render();
 			break;
+		}
 		case Type::Category::FixedBytes:
 		{
 			FixedBytesType const& from = dynamic_cast<FixedBytesType const&>(_from);

test/libsolidity/semanticTests/structs/calldata/calldata_struct_to_memory.sol

@@ -1,6 +1,5 @@
 pragma experimental ABIEncoderV2;
 
-
 contract C {
     struct S {
         uint256 a;
@@ -13,5 +12,7 @@ contract C {
     }
 }
 
+// ====
+// compileViaYul: also
 // ----
 // f((uint256,uint256)): 42, 23 -> 42, 23

test/libsolidity/semanticTests/various/nested_calldata_struct_to_memory.sol

@@ -23,5 +23,7 @@ contract C {
     }
 }
 
+// ====
+// compileViaYul: also
 // ----
 // f((uint256,uint256,(uint256,uint256),uint256)): 1, 2, 3, 4, 5 -> 1, 2, 3, 4, 5