Merge pull request #1327 from ethereum/inline-assembly-errortag

ErrorTag in inline assembly

5 files changed, 30 insertions, 1 deletions

diff --git a/Changelog.md b/Changelog.md
index 4d68fc69..a392ec01 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -2,6 +2,7 @@
 
 Features:
  * Do-while loops: support for a C-style do{<block>}while(<expr>); control structure
+ * Inline assembly: support ``invalidJumpLabel`` as a jump label.
  * Type checker: now more eagerly searches for a common type of an inline array with mixed types
  * Code generator: generates a runtime error when an out-of-range value is converted into an enum type.
 
diff --git a/docs/control-structures.rst b/docs/control-structures.rst
index bbb90e6a..7e1c690d 100644
--- a/docs/control-structures.rst
+++ b/docs/control-structures.rst
@@ -716,6 +716,10 @@ will have a wrong impression about the stack height at label ``two``:
         three:
     }
 
+.. 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
 ----------------------------------
diff --git a/libsolidity/inlineasm/AsmCodeGen.cpp b/libsolidity/inlineasm/AsmCodeGen.cpp
index 76c71048..771f1042 100644
--- a/libsolidity/inlineasm/AsmCodeGen.cpp
+++ b/libsolidity/inlineasm/AsmCodeGen.cpp
@@ -81,7 +81,11 @@ struct GeneratorState
 class LabelOrganizer: public boost::static_visitor<>
 {
 public:
-	LabelOrganizer(GeneratorState& _state): m_state(_state) {}
+	LabelOrganizer(GeneratorState& _state): m_state(_state)
+	{
+		// Make the Solidity ErrorTag available to inline assembly
+		m_state.labels.insert(make_pair("invalidJumpLabel", m_state.assembly.errorTag()));
+	}
 
 	template <class T>
 	void operator()(T const& /*_item*/) { }
diff --git a/test/libsolidity/InlineAssembly.cpp b/test/libsolidity/InlineAssembly.cpp
index a80a44a2..185a6215 100644
--- a/test/libsolidity/InlineAssembly.cpp
+++ b/test/libsolidity/InlineAssembly.cpp
@@ -177,6 +177,11 @@ BOOST_AUTO_TEST_CASE(imbalanced_stack)
 	BOOST_CHECK(successAssemble("{ let x := 4 7 add }", false));
 }
 
+BOOST_AUTO_TEST_CASE(error_tag)
+{
+	BOOST_CHECK(successAssemble("{ invalidJumpLabel }"));
+}
+
 BOOST_AUTO_TEST_SUITE_END()
 
 }
diff --git a/test/libsolidity/SolidityEndToEndTest.cpp b/test/libsolidity/SolidityEndToEndTest.cpp
index 739a2efd..d8924250 100644
--- a/test/libsolidity/SolidityEndToEndTest.cpp
+++ b/test/libsolidity/SolidityEndToEndTest.cpp
@@ -7692,6 +7692,21 @@ 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_SUITE_END()
 
 }