Revert "Added AssertThis opcode and modified translator to emit it"

hphp/doc/ir.specification

@@ -349,12 +349,6 @@ CheckLoc<T,localId> S0:FramePtr -> L
   Check that type of the given localId on the frame S0 is T; if not,
   branch to the label L.
 
-AssertThis 
-
-  Asserts that the $this variable is valid in the current frame.  This 
-  instruction is a hint to perform optimizations in later passes but does 
-  not have any runtime behavior.
-
 AssertLoc<T,localId> S0:FramePtr
 
   Asserts that type of the supplied local on the frame S0 is T.  This

hphp/runtime/vm/jit/codegen.cpp

@@ -356,7 +356,6 @@ NOOP_OPCODE(AssertLoc)
 NOOP_OPCODE(OverrideLoc)
 NOOP_OPCODE(AssertStk)
 NOOP_OPCODE(AssertStkVal)
-NOOP_OPCODE(AssertThis)
 NOOP_OPCODE(Nop)
 NOOP_OPCODE(DefLabel)
 NOOP_OPCODE(ExceptionBarrier)

hphp/runtime/vm/jit/hhbctranslator.cpp

@@ -371,10 +371,6 @@ void HhbcTranslator::emitUnboxR() {
   emitUnboxRAux();
 }
 
-void HhbcTranslator::assertThis() {
-  gen(AssertThis);
-}
-
 void HhbcTranslator::emitThis() {
   if (!curClass()) {
     emitInterpOne(Type::Obj, 0); // will throw a fatal
@@ -2379,6 +2375,10 @@ void HhbcTranslator::emitRetV(bool freeInline) {
   emitRet(Type::BoxedCell, freeInline);
 }
 
+void HhbcTranslator::setThisAvailable() {
+  m_tb->setThisAvailable();
+}
+
 void HhbcTranslator::guardTypeLocal(uint32_t locId, Type type) {
   gen(GuardLoc, type, LocalId(locId), m_tb->fp());
 }

hphp/runtime/vm/jit/hhbctranslator.h

@@ -126,7 +126,6 @@ struct HhbcTranslator {
                  const vector<bool>& vals);
 
   // Interface to irtranslator for predicted and inferred types.
-  void assertThis();
   void assertTypeLocal(uint32_t localIndex, Type type);
   void assertTypeStack(uint32_t stackIndex, Type type);
   void checkTypeLocal(uint32_t localIndex, Type type, Offset dest = -1);
@@ -151,6 +150,7 @@ struct HhbcTranslator {
   void profileFailedInlShape(const std::string& str);
 
   // Other public functions for irtranslator.
+  void setThisAvailable();
   void emitInterpOne(Type type, int numPopped, int numExtraPushed = 0);
   void emitInterpOneCF(int numPopped);
 

hphp/runtime/vm/jit/ir.h

@@ -170,7 +170,6 @@ O(GuardRefs,                        ND, S(Func)                               \
                                           S(Int)                              \
                                           S(Int),                          E) \
 O(AssertLoc,                        ND, S(FramePtr),                       E) \
-O(AssertThis,                       ND, NA,                                E) \
 O(OverrideLoc,                      ND, S(FramePtr),                       E) \
 O(BeginCatch,                       ND, NA,                            E|Mem) \
 O(EndCatch,                         ND, S(StkPtr),                     E|Mem) \

hphp/runtime/vm/jit/irtranslator.cpp

@@ -1572,7 +1572,8 @@ void Translator::translateInstr(const NormalizedInstruction& i) {
                         i.breaksTracelet && !m_hhbcTrans->isInlining());
 
   if (i.guardedThis) {
-    m_hhbcTrans->assertThis();
+    // Task #2067635: This should really generate an AssertThis
+    m_hhbcTrans->setThisAvailable();
   }
 
   if (moduleEnabled(HPHP::Trace::stats, 2)) {

hphp/runtime/vm/jit/tracebuilder.cpp

@@ -221,10 +221,6 @@ void TraceBuilder::updateTrackedState(IRInstruction* inst) {
     m_spValue = inst->dst();
     break;
 
-  case AssertThis:
-    m_thisIsAvailable = true;
-    break;
-
   case SpillStack: {
     m_spValue = inst->dst();
     // Push the spilled values but adjust for the popped values

hphp/runtime/vm/jit/tracebuilder.h

@@ -107,6 +107,9 @@ struct TraceBuilder {
   bool isThisAvailable() const {
     return m_thisIsAvailable;
   }
+  void setThisAvailable() {
+    m_thisIsAvailable = true;
+  }
 
   Type getLocalType(unsigned id) const;
   SSATmp* getLocalValue(unsigned id) const;