Merge pull request #2194 from ethereum/removeerrorlabel

Remove error label / invalid jump label.

docs/assembly.rst

@@ -431,11 +431,6 @@ As an example how this can be done in extreme cases, please see the following.
         pop // We have to pop the manually pushed value here again.
     }
 
-.. note::
-
-    ``invalidJumpLabel`` is a pre-defined label. Jumping to this location will always
-    result in an invalid jump, effectively aborting execution of the code.
-
 Declaring Assembly-Local Variables
 ----------------------------------
 
@@ -699,7 +694,7 @@ The following assembly will be generated::
         mstore(ret, r)
         return(ret, 0x20)
       }
-      default: { jump(invalidJumpLabel) }
+      default: { revert(0, 0) }
       // memory allocator
       function $allocate(size) -> pos {
         pos := mload(0x40)
@@ -744,7 +739,7 @@ After the desugaring phase it looks as follows::
         }
         $caseDefault:
         {
-          jump(invalidJumpLabel)
+          revert(0, 0)
           jump($endswitch)
         }
         $endswitch:

libsolidity/codegen/CompilerUtils.cpp

@@ -299,25 +299,6 @@ void CompilerUtils::zeroInitialiseMemoryArray(ArrayType const& _type)
 	m_context << Instruction::SWAP1 << Instruction::POP;
 }
 
-void CompilerUtils::memoryCopyPrecompile()
-{
-	// Stack here: size target source
-
-	m_context.appendInlineAssembly(R"(
-		{
-		let words := div(add(len, 31), 32)
-		let cost := add(15, mul(3, words))
-		jumpi(invalidJumpLabel, iszero(call(cost, $identityContractAddress, 0, src, len, dst, len)))
-		}
-	)",
-		{ "len", "dst", "src" },
-		map<string, string> {
-			{ "$identityContractAddress", toString(identityContractAddress) }
-		}
-	);
-	m_context << Instruction::POP << Instruction::POP << Instruction::POP;
-}
-
 void CompilerUtils::memoryCopy32()
 {
 	// Stack here: size target source

libsolidity/codegen/CompilerUtils.h

@@ -109,10 +109,6 @@ public:
 	/// Stack post: <updated_memptr>
 	void zeroInitialiseMemoryArray(ArrayType const& _type);
 
-	/// Uses a CALL to the identity contract to perform a memory-to-memory copy.
-	/// Stack pre: <size> <target> <source>
-	/// Stack post:
-	void memoryCopyPrecompile();
 	/// Copies full 32 byte words in memory (regions cannot overlap), i.e. may copy more than length.
 	/// Stack pre: <size> <target> <source>
 	/// Stack post:

libsolidity/inlineasm/AsmCodeGen.cpp

@@ -278,8 +278,6 @@ private:
 	{
 		if (_label.id == Scope::Label::unassignedLabelId)
 			_label.id = m_state.newLabelId();
-		else if (_label.id == Scope::Label::errorLabelId)
-			_label.id = size_t(m_state.assembly.errorTag().data());
 	}
 
 

libsolidity/inlineasm/AsmScope.h

@@ -73,7 +73,6 @@ struct Scope
 	struct Label
 	{
 		size_t id = unassignedLabelId;
-		static const size_t errorLabelId = -1;
 		static const size_t unassignedLabelId = 0;
 	};
 

libsolidity/inlineasm/AsmScopeFiller.cpp

@@ -39,10 +39,6 @@ using namespace dev::solidity::assembly;
 ScopeFiller::ScopeFiller(ScopeFiller::Scopes& _scopes, ErrorList& _errors):
 	m_scopes(_scopes), m_errors(_errors)
 {
-	// Make the Solidity ErrorTag available to inline assembly
-	Scope::Label errorLabel;
-	errorLabel.id = Scope::Label::errorLabelId;
-	scope(nullptr).identifiers["invalidJumpLabel"] = errorLabel;
 	m_currentScope = &scope(nullptr);
 }
 

test/libsolidity/InlineAssembly.cpp

@@ -358,7 +358,7 @@ BOOST_AUTO_TEST_CASE(imbalanced_stack)
 
 BOOST_AUTO_TEST_CASE(error_tag)
 {
-	BOOST_CHECK(successAssemble("{ jump(invalidJumpLabel) }"));
+	CHECK_ASSEMBLE_ERROR("{ jump(invalidJumpLabel) }", DeclarationError, "Identifier not found");
 }
 
 BOOST_AUTO_TEST_CASE(designated_invalid_instruction)

test/libsolidity/SolidityEndToEndTest.cpp

@@ -9126,21 +9126,6 @@ BOOST_AUTO_TEST_CASE(packed_storage_overflow)
 	BOOST_CHECK(callContractFunction("f()") == encodeArgs(u256(0x1234), u256(0), u256(0), u256(0xfffe)));
 }
 
-BOOST_AUTO_TEST_CASE(inline_assembly_invalidjumplabel)
-{
-	char const* sourceCode = R"(
-		contract C {
-			function f() {
-				assembly {
-					jump(invalidJumpLabel)
-				}
-			}
-		}
-	)";
-	compileAndRun(sourceCode, 0, "C");
-	BOOST_CHECK(callContractFunction("f()") == encodeArgs());
-}
-
 BOOST_AUTO_TEST_CASE(contracts_separated_with_comment)
 {
 	char const* sourceCode = R"(