Kill m_should_throw

Do not check for m_should_throw from ContReceive. Add a label used by
ContRaise pointing to Throw emitted by the Yield instead.

hphp/compiler/analysis/emitter.cpp

@@ -3906,16 +3906,26 @@ bool EmitterVisitor::visitImpl(ConstructPtr node) {
         assert(m_evalStack.size() == 1);
         m_metaInfo.addKnownDataType(
           KindOfObject, false, m_ue.bcPos(), false, 1);
-        e.PackCont(y->getLabel());
+        e.PackCont(2 * y->getLabel());
 
         // transfer control
         assert(m_evalStack.size() == 0);
         e.ContExit();
 
-        // emit return label
-        m_yieldLabels[y->getLabel()].set(e);
+        // emit return label for ContRaise
+        m_yieldLabels[2 * y->getLabel() - 1].set(e);
 
-        // check for exception and retrieve result
+        // retrieve and throw exception
+        assert(m_evalStack.size() == 0);
+        m_metaInfo.addKnownDataType(
+          KindOfObject, false, m_ue.bcPos(), false, 0);
+        e.ContReceive();
+        e.Throw();
+
+        // emit return label for ContNext/ContSend
+        m_yieldLabels[2 * y->getLabel()].set(e);
+
+        // retrieve result
         assert(m_evalStack.size() == 0);
         m_metaInfo.addKnownDataType(
           KindOfObject, false, m_ue.bcPos(), false, 0);
@@ -4904,17 +4914,10 @@ void EmitterVisitor::emitContinuationSwitch(Emitter& e, int ncase) {
   }
 
   // make sure the labels are available
-  m_yieldLabels.resize(ncase + 1);
+  m_yieldLabels.resize(2 * ncase + 1);
 
-  if (ncase == 1) {
-    // Don't bother with the jump table when there are only two targets
-    e.UnpackCont();
-    e.JmpNZ(m_yieldLabels[1]);
-    return;
-  }
-
-  std::vector<Label*> targets(ncase + 1);
-  for (int i = 0; i <= ncase; ++i) {
+  std::vector<Label*> targets(2 * ncase + 1);
+  for (int i = 0; i <= 2 * ncase; ++i) {
     targets[i] = &m_yieldLabels[i];
   }
   e.UnpackCont();

hphp/compiler/expression/yield_expression.h

@@ -32,7 +32,7 @@ public:
   DECLARE_EXPRESSION_VIRTUAL_FUNCTIONS;
 
   ExpressionPtr getExpression() { return m_exp; }
-  int getLabel() { assert(m_label >= 0); return m_label; }
+  int getLabel() { assert(m_label >= 1); return m_label; }
   void setLabel(int label) { assert(m_label == -1); m_label = label; }
 
 private:

hphp/runtime/ext/ext_continuation.cpp

@@ -49,7 +49,7 @@ c_Continuation::c_Continuation(Class* cb) :
     m_index(-1LL),
     m_value(Variant::NullInit()),
     m_received(Variant::NullInit()),
-    m_done(false), m_running(false), m_should_throw(false),
+    m_done(false), m_running(false),
     m_vmFunc(nullptr), m_label(0ll) {
 }
 
@@ -139,15 +139,6 @@ void c_Continuation::t_raise(CVarRef v) {
   const_assert(false);
 }
 
-void c_Continuation::t_raised() {
-  if (m_should_throw) {
-    m_should_throw = false;
-    Variant e((Variant::NullInit()));
-    m_received.swap(e);
-    throw_exception(e);
-  }
-}
-
 String c_Continuation::t_getorigfuncname() {
   return String(const_cast<StringData*>(m_origFuncName));
 }

hphp/runtime/ext/ext_continuation.h

@@ -78,7 +78,6 @@ public:
   bool t_valid();
   void t_send(CVarRef v);
   void t_raise(CVarRef v);
-  void t_raised();
   String t_getorigfuncname();
   String t_getcalledclass();
   Variant t___clone();
@@ -130,7 +129,6 @@ public:
   const StringData* m_origFuncName;
   bool m_done;
   bool m_running;
-  bool m_should_throw;
 
   int m_localsOffset;
   Func *m_vmFunc;

hphp/runtime/vm/bytecode.cpp

@@ -7281,7 +7281,6 @@ inline void OPTBLD_INLINE VMExecutionContext::iopPackCont(PC& pc) {
 inline void OPTBLD_INLINE VMExecutionContext::iopContReceive(PC& pc) {
   NEXT();
   c_Continuation* cont = frame_continuation(m_fp);
-  cont->t_raised();
   TypedValue* fr = cont->m_received.asTypedValue();
   TypedValue* to = m_stack.allocTV();
   memcpy(to, fr, sizeof(TypedValue));
@@ -7315,7 +7314,8 @@ inline void VMExecutionContext::contSendImpl() {
   cont->preNext();
   cont->m_received.assignVal(tvAsVariant(frame_local(m_fp, 0)));
   if (raise) {
-    cont->m_should_throw = true;
+    assert(cont->m_label);
+    --cont->m_label;
   }
 }
 

hphp/runtime/vm/jit/codegen.cpp

@@ -5132,13 +5132,6 @@ void CodeGenerator::cgLinkContVarEnv(IRInstruction* inst) {
     (TCA)VMExecutionContext::unpackContVarEnvLinkage);
 }
 
-void CodeGenerator::cgContRaiseCheck(IRInstruction* inst) {
-  SSATmp* cont = inst->src(0);
-  m_as.test_imm32_disp_reg32(0x1, CONTOFF(m_should_throw),
-                             m_regs[cont].reg());
-  emitFwdJcc(CC_NZ, inst->taken());
-}
-
 void CodeGenerator::cgContPreNext(IRInstruction* inst) {
   auto contReg = m_regs[inst->src(0)].reg();
 

hphp/runtime/vm/jit/hhbctranslator.cpp

@@ -1120,7 +1120,6 @@ void HhbcTranslator::emitPackCont(int64_t labelId) {
 void HhbcTranslator::emitContReceive() {
   gen(AssertLoc, Type::Obj, LocalId(0), m_tb->fp());
   auto const cont = ldLoc(0);
-  gen(ContRaiseCheck, getExitSlowTrace(), cont);
   auto const valOffset = cns(CONTOFF(m_received));
   push(gen(LdProp, Type::Cell, cont, valOffset));
   gen(StProp, cont, valOffset, m_tb->genDefNull());
@@ -1167,7 +1166,9 @@ void HhbcTranslator::emitContSendImpl(bool raise) {
   }
   gen(StProp, cont, cns(CONTOFF(m_received)), newVal);
   if (raise) {
-    gen(StRaw, cont, cns(RawMemSlot::ContShouldThrow), cns(true));
+    SSATmp* label = gen(LdRaw, Type::Int, cont, cns(RawMemSlot::ContLabel));
+    label = gen(OpSub, label, cns(1));
+    gen(StRaw, cont, cns(RawMemSlot::ContLabel), label);
   }
 }
 

hphp/runtime/vm/jit/ir.h

@@ -451,7 +451,6 @@ O(ContEnter,                        ND, S(FramePtr)                           \
                                           S(TCA) C(Int) S(FramePtr),   E|Mem) \
 O(UnlinkContVarEnv,                 ND, S(FramePtr),                 E|N|Mem) \
 O(LinkContVarEnv,                   ND, S(FramePtr),                 E|N|Mem) \
-O(ContRaiseCheck,                   ND, S(Obj),                            E) \
 O(ContPreNext,                      ND, S(Obj),                        E|Mem) \
 O(ContStartedCheck,                 ND, S(Obj),                            E) \
 O(IterInit,                    D(Bool), S(Arr,Obj)                            \
@@ -759,7 +758,7 @@ class RawMemSlot {
  public:
 
   enum Kind {
-    ContLabel, ContDone, ContShouldThrow, ContRunning, ContARPtr,
+    ContLabel, ContDone, ContRunning, ContARPtr,
     StrLen, FuncNumParams, FuncRefBitVec, ContEntry, MisCtx,
     MaxKind
   };
@@ -768,7 +767,6 @@ class RawMemSlot {
     switch (k) {
       case ContLabel:       return GetContLabel();
       case ContDone:        return GetContDone();
-      case ContShouldThrow: return GetContShouldThrow();
       case ContRunning:     return GetContRunning();
       case ContARPtr:       return GetContARPtr();
       case StrLen:          return GetStrLen();
@@ -797,10 +795,6 @@ class RawMemSlot {
     static RawMemSlot m(CONTOFF(m_done), Transl::sz::byte, Type::Bool);
     return m;
   }
-  static RawMemSlot& GetContShouldThrow() {
-    static RawMemSlot m(CONTOFF(m_should_throw), Transl::sz::byte, Type::Bool);
-    return m;
-  }
   static RawMemSlot& GetContRunning() {
     static RawMemSlot m(CONTOFF(m_running), Transl::sz::byte, Type::Bool);
     return m;