From 90b66a736250a1af0a897f0c5c67cecbdd4b74f6 Mon Sep 17 00:00:00 2001
From: Daniel Kirchner <daniel@ekpyron.org>
Date: Wed, 10 Jun 2020 17:27:59 +0200
Subject: [PATCH] Fix struct member access for memory and implement for
 calldata.

---
 libsolidity/ast/Types.cpp                     | 15 +++++++
 libsolidity/ast/Types.h                       |  2 +
 .../codegen/ir/IRGeneratorForStatements.cpp   | 22 ++++++++++-
 .../viaYul/struct_member_access.sol           | 39 +++++++++++++++++++
 4 files changed, 76 insertions(+), 2 deletions(-)
 create mode 100644 test/libsolidity/semanticTests/viaYul/struct_member_access.sol

diff --git a/libsolidity/ast/Types.cpp b/libsolidity/ast/Types.cpp
index 8114be800..dfddaef8e 100644
--- a/libsolidity/ast/Types.cpp
+++ b/libsolidity/ast/Types.cpp
@@ -2457,6 +2457,21 @@ set<string> StructType::membersMissingInMemory() const
 	return missing;
 }
 
+vector<tuple<string, TypePointer>> StructType::makeStackItems() const
+{
+	switch (m_location)
+	{
+		case DataLocation::CallData:
+			return {std::make_tuple("offset", TypeProvider::uint256())};
+		case DataLocation::Memory:
+			return {std::make_tuple("mpos", TypeProvider::uint256())};
+		case DataLocation::Storage:
+			return {std::make_tuple("slot", TypeProvider::uint256())};
+	}
+	solAssert(false, "");
+}
+
+
 TypePointer EnumType::encodingType() const
 {
 	return TypeProvider::uint(8 * storageBytes());
diff --git a/libsolidity/ast/Types.h b/libsolidity/ast/Types.h
index 609f2e9ed..4ae780b63 100644
--- a/libsolidity/ast/Types.h
+++ b/libsolidity/ast/Types.h
@@ -980,6 +980,8 @@ public:
 
 	void clearCache() const override;
 
+protected:
+	std::vector<std::tuple<std::string, TypePointer>> makeStackItems() const override;
 private:
 	StructDefinition const& m_struct;
 	// Caches for interfaceType(bool)
diff --git a/libsolidity/codegen/ir/IRGeneratorForStatements.cpp b/libsolidity/codegen/ir/IRGeneratorForStatements.cpp
index a62251ab1..53e23d849 100644
--- a/libsolidity/codegen/ir/IRGeneratorForStatements.cpp
+++ b/libsolidity/codegen/ir/IRGeneratorForStatements.cpp
@@ -1477,7 +1477,7 @@ void IRGeneratorForStatements::endVisit(MemberAccess const& _memberAccess)
 			pair<u256, unsigned> const& offsets = structType.storageOffsetsOfMember(member);
 			string slot = m_context.newYulVariable();
 			m_code << "let " << slot << " := " <<
-				("add(" + expression.name() + ", " + offsets.first.str() + ")\n");
+				("add(" + expression.part("slot").name() + ", " + offsets.first.str() + ")\n");
 			setLValue(_memberAccess, IRLValue{
 				type(_memberAccess),
 				IRLValue::Storage{slot, offsets.second}
@@ -1497,7 +1497,25 @@ void IRGeneratorForStatements::endVisit(MemberAccess const& _memberAccess)
 		}
 		case DataLocation::CallData:
 		{
-			solUnimplementedAssert(false, "");
+			string baseRef = expression.part("offset").name();
+			string offset = m_context.newYulVariable();
+			m_code << "let " << offset << " := " << "add(" << baseRef << ", " << to_string(structType.calldataOffsetOfMember(member)) << ")\n";
+			if (_memberAccess.annotation().type->isDynamicallyEncoded())
+				define(_memberAccess) <<
+					m_utils.accessCalldataTailFunction(*_memberAccess.annotation().type) <<
+					"(" <<
+					baseRef <<
+					", " <<
+					offset <<
+					")" <<
+					std::endl;
+			else
+				define(_memberAccess) <<
+					m_utils.readFromCalldata(*_memberAccess.annotation().type) <<
+					"(" <<
+					offset <<
+					")" <<
+					std::endl;
 			break;
 		}
 		default:
diff --git a/test/libsolidity/semanticTests/viaYul/struct_member_access.sol b/test/libsolidity/semanticTests/viaYul/struct_member_access.sol
new file mode 100644
index 000000000..60733d414
--- /dev/null
+++ b/test/libsolidity/semanticTests/viaYul/struct_member_access.sol
@@ -0,0 +1,39 @@
+pragma experimental ABIEncoderV2;
+
+contract C {
+    struct S {
+        uint a;
+        uint[] b;
+        uint c;
+    }
+
+    S s;
+    constructor() public {
+        s.a = 42;
+        s.b.push(1);
+        s.b.push(2);
+        s.b.push(3);
+        s.c = 21;
+    }
+
+    function f(S memory m) public pure returns (uint, uint[] memory, uint) {
+        return (m.a, m.b, m.c);
+    }
+    function g(S calldata c) external pure returns (uint, uint, uint, uint, uint, uint) {
+        return (c.a, c.b.length, c.c, c.b[0], c.b[1], c.b[2]);
+    }
+    function g2(S calldata c1, S calldata c2) external pure returns (uint, uint, uint, uint, uint, uint) {
+        return (c1.a, c1.c, c2.a, c2.b.length, c2.c, c2.b[0]);
+    }
+    function h() external view returns (uint, uint, uint, uint, uint, uint) {
+        return (s.a, s.b.length, s.c, s.b[0], s.b[1], s.b[2]);
+    }
+}
+// ====
+// EVMVersion: >homestead
+// compileViaYul: also
+// ----
+// f((uint256,uint256[],uint256)): 0x20, 42, 0x60, 21, 3, 1, 2, 3 -> 42, 0x60, 21, 3, 1, 2, 3
+// g((uint256,uint256[],uint256)): 0x20, 42, 0x60, 21, 3, 1, 2, 3 -> 42, 3, 21, 1, 2, 3
+// g2((uint256,uint256[],uint256),(uint256,uint256[],uint256)): 0x40, 0x0120, 42, 0x60, 21, 2, 1, 2, 3, 7, 0x80, 9, 0, 1, 17  -> 42, 21, 7, 1, 9, 17
+// h() -> 42, 3, 21, 1, 2, 3