Debugger: Fix GDB hanging

This partially reverts commit e33da6a6b3.
GDB seems to hang while executing str(some_pointer) in some setups.

Task-number: QTCREATORBUG-14374
Change-Id: Ia678533b9122e505b21ef6659d404239995ddb81
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
Reviewed-by: Christian Stenger <christian.stenger@theqtcompany.com>

share/qtcreator/debugger/dumper.py

@@ -1040,21 +1040,8 @@ class DumperBase:
             return
 
         typeName = str(value.type)
-        innerType = value.type.target().unqualified()
-        innerTypeName = str(innerType)
 
-        goodPointer = False
+        if self.isBadPointer(value):
-        try:
-            target = value.dereference()
-            str(target) # Dummy access.
-            if self.isLldb and target.GetError().Fail():
-                pass
-            else:
-                goodPointer = True
-        except:
-            pass
-
-        if not goodPointer:
             # Failure to dereference a pointer should at least
             # show the value of a pointer.
             self.putValue(self.cleanAddress(value))
@@ -1063,6 +1050,8 @@ class DumperBase:
             return
 
         displayFormat = self.currentItemFormat(value.type)
+        innerType = value.type.target().unqualified()
+        innerTypeName = str(innerType)
 
         if innerTypeName == "void":
             #warn("VOID POINTER: %s" % displayFormat)

share/qtcreator/debugger/gdbbridge.py

@@ -522,6 +522,14 @@ class Dumper(DumperBase):
         except:
             return None
 
+    def isBadPointer(self, value):
+        try:
+            target = value.dereference()
+            target.is_optimized_out # Access test.
+            return False
+        except:
+            return True
+
     def makeValue(self, typeobj, init):
         typename = "::" + self.stripClassTag(str(typeobj));
         # Avoid malloc symbol clash with QVector.

share/qtcreator/debugger/lldbbridge.py

@@ -365,6 +365,10 @@ class Dumper(DumperBase):
         #self.warn("  -> %s" % result)
         return result
 
+    def isBadPointer(self, value):
+        target = value.dereference()
+        return target.GetError().Fail()
+
     def makeValue(self, type, *args):
         thread = self.currentThread()
         frame = thread.GetFrameAtIndex(0)