fix new clang warnings (from upgrading clang)

src/avian/machine.h

@@ -1703,9 +1703,6 @@ bool instanceOf(Thread* t, GcClass* class_, object o);
 template <class T>
 T* GcObject::as(Thread* t UNUSED)
 {
-  if (this == 0) {
-    return 0;
-  }
   assertT(t,
           t->m->unsafe || instanceOf(t,
                                      reinterpret_cast<GcClass*>(arrayBodyUnsafe(

src/codegen/compiler.cpp

@@ -1909,9 +1909,7 @@ void setStubRead(Context* c, StubReadPair* p, Value* v)
     if (DebugReads) {
       fprintf(stderr, "add stub read %p to %p\n", r, v);
     }
-    // TODO: this is rather icky looking... but despite how it looks, it will
-    // not cause an NPE
-    ((Event*)0)->addRead(c, v, r);
+    finishAddRead(c, v, r);
 
     p->value = v;
     p->read = r;
@@ -2113,9 +2111,7 @@ void addForkElement(Context* c, Value* v, ForkState* state, unsigned index)
   if (DebugReads) {
     fprintf(stderr, "add multi read %p to %p\n", r, v);
   }
-  // TODO: this is rather icky looking... but despite how it looks, it will not
-  // cause an NPE
-  ((Event*)0)->addRead(c, v, r);
+  finishAddRead(c, v, r);
 
   ForkElement* p = state->elements + index;
   p->value = v;

src/codegen/compiler/event.cpp

@@ -136,16 +136,20 @@ void Event::addRead(Context* c, Value* v, Read* r)
             v,
             v->lastRead,
             this,
-            (this ? this->name() : 0));
+            this->name());
   }
 
+  r->event = this;
+  r->eventNext = this->reads;
+  this->reads = r;
+  ++this->readCount;
+
+  finishAddRead(c, v, r);
+}
+
+void finishAddRead(Context* c, Value* v, Read* r)
+{
   r->value = v;
-  if (this) {
-    r->event = this;
-    r->eventNext = this->reads;
-    this->reads = r;
-    ++this->readCount;
-  }
 
   if (v->lastRead) {
     if (DebugReads) {

src/codegen/compiler/event.h

@@ -90,6 +90,8 @@ class Event {
   unsigned readCount;
 };
 
+void finishAddRead(Context* c, Value* v, Read* r);
+
 class StubReadPair {
  public:
   Value* value;

src/compile.cpp

@@ -8266,11 +8266,11 @@ class CompilationHandlerList {
 
   void dispose(Allocator* allocator)
   {
-    if (this) {
+    if (next) {
       next->dispose(allocator);
-      handler->dispose();
-      allocator->free(this, sizeof(*this));
     }
+    handler->dispose();
+    allocator->free(this, sizeof(*this));
   }
 
   CompilationHandlerList* next;
@@ -8804,7 +8804,9 @@ class MyProcessor : public Processor {
 #endif
     }
 
-    compilationHandlers->dispose(allocator);
+    if(compilationHandlers) {
+      compilationHandlers->dispose(allocator);
+    }
 
     signals.unregisterHandler(SignalRegistrar::SegFault);
     signals.unregisterHandler(SignalRegistrar::DivideByZero);

src/tools/binary-to-object/main.cpp

@@ -35,7 +35,7 @@ void* operator new(size_t size)
   return malloc(size);
 }
 
-void operator delete(void*)
+void operator delete(void*) throw()
 {
   abort();
 }