Use a more reliable method to dinstinguish between an op_call and an op_construct

The two opcode operand looks like this.

      -7        -6       -5       -4           -3          -2            -1
  op_construct dst(r) func(r) argCount(n) registerOffset(n) proto(r) thisRegister(r)
                      op_call   dst(r)        func(r)     argCount(n) registerOffset(n)

as the registerOffset must always be bigger than any register we can
use that knoweldge to differenciate the two calls

Note that this is only the fallback used for JavaScript function. native
function still uses the QScriptActivationObject

Reviewed-by: Kent Hansen

1 files changed, 5 insertions, 2 deletions

diff --git a/src/script/api/qscriptcontext.cpp b/src/script/api/qscriptcontext.cpp
index 99b8989..852ed6b 100644
--- a/src/script/api/qscriptcontext.cpp
+++ b/src/script/api/qscriptcontext.cpp
@@ -357,8 +357,11 @@ bool QScriptContext::isCalledAsConstructor() const
 
     if (returnPC[-JSC::op_construct_length].u.opcode == frame->interpreter()->getOpcode(JSC::op_construct)) {
         //We are maybe called from the op_construct opcode which has 6 opperands.
-        //But we need to check we are not called from op_call with 4 opperands (by checking the argc operand)
-        return returnPC[-4].u.operand == frame->argumentCount();
+        //But we need to check we are not called from op_call with 4 opperands
+
+        //we make sure that the returnPC[-1] (thisRegister) is smaller than the returnPC[-3] (registerOffset)
+        //as if it was an op_call, the returnPC[-1] would be the registerOffset, bigger than returnPC[-3] (funcRegister)
+        return returnPC[-1].u.operand < returnPC[-3].u.operand;
     }
     return false;
 }