V4: Fix JavaScript finally-block execution

After moving all runtime functions into the Runtime class and doing
indirect function calls, the code generation would always emit code
to check for an exception after a call. This is problematic for methods
that do not throw, but might be called when an exception is thrown. I.e.
in a finally block. This is especially problematic for methods like
popScope, the very first runtime method that is called in a finally
block. The result was that after popScope, execution was passed over to
the exception handler block for that finally block (meaning: the body
of the finally block was never executed).

The fix is to declare an enumerator in an anonymous enum for each
runtime method that indicates if an exception check is needed. The
existing ExceptionCheck templates are used to set the value.

Change-Id: I5bd8bcf2a92acabf2a33b3764447de6cc364bba9
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 12 insertions, 42 deletions

diff --git a/src/qml/jit/qv4assembler_p.h b/src/qml/jit/qv4assembler_p.h
index e29b165c2d..2ef0db78c0 100644
--- a/src/qml/jit/qv4assembler_p.h
+++ b/src/qml/jit/qv4assembler_p.h
@@ -108,36 +108,6 @@ struct RuntimeCall {
     bool isValid() const { return addr.offset >= 0; }
 };
 
-template <typename T>
-struct ExceptionCheck {
-    enum { NeedsCheck = 1 };
-};
-// push_catch and pop context methods shouldn't check for exceptions
-template <>
-struct ExceptionCheck<void (*)(QV4::ExecutionEngine *)> {
-    enum { NeedsCheck = 0 };
-};
-template <typename A>
-struct ExceptionCheck<void (*)(A, QV4::NoThrowEngine)> {
-    enum { NeedsCheck = 0 };
-};
-template <>
-struct ExceptionCheck<QV4::ReturnedValue (*)(QV4::NoThrowEngine *)> {
-    enum { NeedsCheck = 0 };
-};
-template <typename A>
-struct ExceptionCheck<QV4::ReturnedValue (*)(QV4::NoThrowEngine *, A)> {
-    enum { NeedsCheck = 0 };
-};
-template <typename A, typename B>
-struct ExceptionCheck<QV4::ReturnedValue (*)(QV4::NoThrowEngine *, A, B)> {
-    enum { NeedsCheck = 0 };
-};
-template <typename A, typename B, typename C>
-struct ExceptionCheck<void (*)(QV4::NoThrowEngine *, A, B, C)> {
-    enum { NeedsCheck = 0 };
-};
-
 class Assembler : public JSC::MacroAssembler, public TargetPlatform
 {
     Q_DISABLE_COPY(Assembler)
@@ -809,7 +779,7 @@ public:
     };
 
     template <typename ArgRet, typename Callable, typename Arg1, typename Arg2, typename Arg3, typename Arg4, typename Arg5, typename Arg6>
-    void generateFunctionCallImp(ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5, Arg6 arg6)
+    void generateFunctionCallImp(bool needsExceptionCheck, ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5, Arg6 arg6)
     {
         int stackSpaceNeeded =   SizeOnStack<0, Arg1>::Size
                                + SizeOnStack<1, Arg2>::Size
@@ -852,7 +822,7 @@ public:
         if (stackSpaceNeeded)
             addPtr(TrustedImm32(stackSpaceNeeded), StackPointerRegister);
 
-        if (ExceptionCheck<Callable>::NeedsCheck) {
+        if (needsExceptionCheck) {
             checkException();
         }
 
@@ -861,33 +831,33 @@ public:
     }
 
     template <typename ArgRet, typename Callable, typename Arg1, typename Arg2, typename Arg3, typename Arg4, typename Arg5>
-    void generateFunctionCallImp(ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5)
+    void generateFunctionCallImp(bool needsExceptionCheck, ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4, Arg5 arg5)
     {
-        generateFunctionCallImp(r, functionName, function, arg1, arg2, arg3, arg4, arg5, VoidType());
+        generateFunctionCallImp(needsExceptionCheck, r, functionName, function, arg1, arg2, arg3, arg4, arg5, VoidType());
     }
 
     template <typename ArgRet, typename Callable, typename Arg1, typename Arg2, typename Arg3, typename Arg4>
-    void generateFunctionCallImp(ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4)
+    void generateFunctionCallImp(bool needsExceptionCheck, ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3, Arg4 arg4)
     {
-        generateFunctionCallImp(r, functionName, function, arg1, arg2, arg3, arg4, VoidType(), VoidType());
+        generateFunctionCallImp(needsExceptionCheck, r, functionName, function, arg1, arg2, arg3, arg4, VoidType(), VoidType());
     }
 
     template <typename ArgRet, typename Callable, typename Arg1, typename Arg2, typename Arg3>
-    void generateFunctionCallImp(ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3)
+    void generateFunctionCallImp(bool needsExceptionCheck, ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2, Arg3 arg3)
     {
-        generateFunctionCallImp(r, functionName, function, arg1, arg2, arg3, VoidType(), VoidType(), VoidType());
+        generateFunctionCallImp(needsExceptionCheck, r, functionName, function, arg1, arg2, arg3, VoidType(), VoidType(), VoidType());
     }
 
     template <typename ArgRet, typename Callable, typename Arg1, typename Arg2>
-    void generateFunctionCallImp(ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2)
+    void generateFunctionCallImp(bool needsExceptionCheck, ArgRet r, const char* functionName, Callable function, Arg1 arg1, Arg2 arg2)
     {
-        generateFunctionCallImp(r, functionName, function, arg1, arg2, VoidType(), VoidType(), VoidType(), VoidType());
+        generateFunctionCallImp(needsExceptionCheck, r, functionName, function, arg1, arg2, VoidType(), VoidType(), VoidType(), VoidType());
     }
 
     template <typename ArgRet, typename Callable, typename Arg1>
-    void generateFunctionCallImp(ArgRet r, const char* functionName, Callable function, Arg1 arg1)
+    void generateFunctionCallImp(bool needsExceptionCheck, ArgRet r, const char* functionName, Callable function, Arg1 arg1)
     {
-        generateFunctionCallImp(r, functionName, function, arg1, VoidType(), VoidType(), VoidType(), VoidType(), VoidType());
+        generateFunctionCallImp(needsExceptionCheck, r, functionName, function, arg1, VoidType(), VoidType(), VoidType(), VoidType(), VoidType());
     }
 
     Pointer toAddress(RegisterID tmpReg, IR::Expr *e, int offset)