Fix #574. (#576)

* Fix #574.

* Destruct the exception object

Author: h0nzZik

semantics/common/execution/thread_local.k

@@ -49,6 +49,7 @@ module COMMON-THREAD-LOCAL
             <this> .K </this>
             // object being constructed
             <constructing> .K </constructing>
+            <constructing-history> .List </constructing-history>
             // most derived class being constructed
             <most-derived-class> .K </most-derived-class>
 
@@ -82,7 +83,6 @@ module COMMON-THREAD-LOCAL
                  // used to store the catch handlers if this
                  // block is a try block in C++
                  <catch-handlers> .List </catch-handlers>
-                 <current-exception> .K </current-exception>
             </block-control>
 
             // used to control initialization when gotoing
@@ -99,6 +99,7 @@ module COMMON-THREAD-LOCAL
             // Used to catch potential stack size overflows.
             <stack-depth> 0 </stack-depth>
 
+            <current-exception> .K </current-exception>
             <uncaught-exception> false </uncaught-exception>
 
             // stdarg

semantics/cpp/language/execution/binding.k

@@ -56,11 +56,19 @@ module CPP-EXECUTION-BINDING
           <this> _ => Obj </this>
 
      rule <k> beginConstruction(Obj:LVal, IsBaseClassSubobject:Bool) => Obj ...</k>
-          <constructing> _ => Obj </constructing>
-          <most-derived-class> MostDerived:K => #if IsBaseClassSubobject #then MostDerived #else type(Obj) #fi </most-derived-class>
+          <constructing> Old::K => Obj </constructing>
+          <constructing-history>
+               .List => ListItem(<constructing>Old</constructing>)
+          ...</constructing-history>
+          <most-derived-class>
+               MostDerived:K => #if IsBaseClassSubobject #then MostDerived #else type(Obj) #fi
+          </most-derived-class>
 
      rule <k> endConstruction(Obj:LVal, IsConstructor::Bool) => finishConstruction(Obj, IsConstructor) ...</k>
-          <constructing> _ => .K </constructing>
+          <constructing> _ => Old </constructing>
+          <constructing-history>
+               ListItem(<constructing> Old::K </constructing>) => .List
+          ...</constructing-history>
 
      rule <k> finishConstruction(Obj:LVal, IsConstructor:Bool) => Obj ...</k>
           <locally-constructed> .List =>

semantics/cpp/language/execution/stmt/try.k

@@ -196,8 +196,9 @@ module CPP-EXECUTION-STMT-TRY
      rule <k> activateHandler => .K ...</k>
           <uncaught-exception> _ => false </uncaught-exception>
 
-     rule <k> deactivateHandler => .K ...</k>
-          <current-exception> _ => .K </current-exception>
+     // @ref n4296 15.1/4
+     rule <k> deactivateHandler => destructLocal(false, lcentry(V, true, true, false)) ...</k>
+          <current-exception> V::LVal => .K </current-exception>
 
      rule tryMark(_) => .K
 

tests/unit-pass/copy-construction.C

@@ -0,0 +1,18 @@
+struct E {
+	E(){}
+	~E(){}
+	E(E const &){}
+	int x;
+};
+
+E foo() { 
+	return E();
+	//return {};
+}
+
+int main() {
+	foo();
+	//E(E());
+	E e = E();
+	try { throw E(); } catch(...){}
+}

tests/unit-pass/destruct-thrown.C

@@ -0,0 +1,15 @@
+extern "C" int puts(char const *);
+
+struct E {
+	int x = 0;
+	E(){puts("E()");}
+	~E(){puts("~E()");}
+	E(E const &){puts("E(E const &)");}
+};
+
+int main() {
+	try {
+		throw E();
+	} catch(E const &e) {}
+	puts("---");
+}