Bug 971319 - Stop passing redundant barriering information through to GetPropertyIC. (r=jandem)

js/src/jit/CodeGenerator.cpp

@@ -6570,11 +6570,11 @@ CodeGenerator::visitNameIC(OutOfLineUpdateCache *ool, DataPtr<NameIC> &ic)
 bool
 CodeGenerator::addGetPropertyCache(LInstruction *ins, RegisterSet liveRegs, Register objReg,
                                    PropertyName *name, TypedOrValueRegister output,
-                                   bool allowGetters, bool monitoredResult)
+                                   bool monitoredResult)
 {
     switch (gen->info().executionMode()) {
       case SequentialExecution: {
-        GetPropertyIC cache(liveRegs, objReg, name, output, allowGetters, monitoredResult);
+        GetPropertyIC cache(liveRegs, objReg, name, output, monitoredResult);
         return addCache(ins, allocateCache(cache));
       }
       case ParallelExecution: {
@@ -6632,11 +6632,10 @@ CodeGenerator::visitGetPropertyCacheV(LGetPropertyCacheV *ins)
     RegisterSet liveRegs = ins->safepoint()->liveRegs();
     Register objReg = ToRegister(ins->getOperand(0));
     PropertyName *name = ins->mir()->name();
-    bool allowGetters = ins->mir()->allowGetters();
     bool monitoredResult = ins->mir()->monitoredResult();
     TypedOrValueRegister output = TypedOrValueRegister(GetValueOutput(ins));
 
-    return addGetPropertyCache(ins, liveRegs, objReg, name, output, allowGetters, monitoredResult);
+    return addGetPropertyCache(ins, liveRegs, objReg, name, output, monitoredResult);
 }
 
 bool
@@ -6645,11 +6644,10 @@ CodeGenerator::visitGetPropertyCacheT(LGetPropertyCacheT *ins)
     RegisterSet liveRegs = ins->safepoint()->liveRegs();
     Register objReg = ToRegister(ins->getOperand(0));
     PropertyName *name = ins->mir()->name();
-    bool allowGetters = ins->mir()->allowGetters();
     bool monitoredResult = ins->mir()->monitoredResult();
     TypedOrValueRegister output(ins->mir()->type(), ToAnyRegister(ins->getDef(0)));
 
-    return addGetPropertyCache(ins, liveRegs, objReg, name, output, allowGetters, monitoredResult);
+    return addGetPropertyCache(ins, liveRegs, objReg, name, output, monitoredResult);
 }
 
 typedef bool (*GetPropertyICFn)(JSContext *, size_t, HandleObject, MutableHandleValue);

js/src/jit/CodeGenerator.h

@@ -351,7 +351,7 @@ class CodeGenerator : public CodeGeneratorSpecific
   private:
     bool addGetPropertyCache(LInstruction *ins, RegisterSet liveRegs, Register objReg,
                              PropertyName *name, TypedOrValueRegister output,
-                             bool allowGetters, bool monitoredResult);
+                             bool monitoredResult);
     bool addGetElementCache(LInstruction *ins, Register obj, ConstantOrRegister index,
                             TypedOrValueRegister output, bool monitoredResult,
                             bool allowDoubleResult);

js/src/jit/IonBuilder.cpp

@@ -8723,7 +8723,6 @@ IonBuilder::getPropTryCache(bool *emitted, PropertyName *name,
                             bool barrier, types::TemporaryTypeSet *types)
 {
     JS_ASSERT(*emitted == false);
-    bool accessGetter = inspector->hasSeenAccessedGetter(pc);
 
     MDefinition *obj = current->peek(-1);
 
@@ -8735,7 +8734,9 @@ IonBuilder::getPropTryCache(bool *emitted, PropertyName *name,
             return true;
     }
 
-    if (accessGetter)
+    // Since getters have no guaranteed return values, we must barrier in order to be
+    // able to attach stubs for them.
+    if (inspector->hasSeenAccessedGetter(pc))
         barrier = true;
 
     if (needsToMonitorMissingProperties(types))
@@ -8767,10 +8768,6 @@ IonBuilder::getPropTryCache(bool *emitted, PropertyName *name,
             return false;
     }
 
-    // If the cache is known to access getters, then enable generation of getter stubs.
-    if (accessGetter)
-        load->setAllowGetters();
-
     current->add(load);
     current->push(load);
 

js/src/jit/IonCaches.h

@@ -530,7 +530,6 @@ class GetPropertyIC : public RepatchIonCache
     size_t locationsIndex_;
     size_t numLocations_;
 
-    bool allowGetters_ : 1;
     bool monitoredResult_ : 1;
     bool hasTypedArrayLengthStub_ : 1;
     bool hasStrictArgumentsLengthStub_ : 1;
@@ -541,14 +540,13 @@ class GetPropertyIC : public RepatchIonCache
     GetPropertyIC(RegisterSet liveRegs,
                   Register object, PropertyName *name,
                   TypedOrValueRegister output,
-                  bool allowGetters, bool monitoredResult)
+                  bool monitoredResult)
       : liveRegs_(liveRegs),
         object_(object),
         name_(name),
         output_(output),
         locationsIndex_(0),
         numLocations_(0),
-        allowGetters_(allowGetters),
         monitoredResult_(monitoredResult),
         hasTypedArrayLengthStub_(false),
         hasStrictArgumentsLengthStub_(false),
@@ -570,9 +568,6 @@ class GetPropertyIC : public RepatchIonCache
     TypedOrValueRegister output() const {
         return output_;
     }
-    bool allowGetters() const {
-        return allowGetters_ && !idempotent();
-    }
     bool monitoredResult() const {
         return monitoredResult_;
     }
@@ -609,6 +604,9 @@ class GetPropertyIC : public RepatchIonCache
     // Helpers for CanAttachNativeGetProp
     typedef JSContext * Context;
     bool allowArrayLength(Context cx, HandleObject obj) const;
+    bool allowGetters() const {
+        return monitoredResult() && !idempotent();
+    }
 
     // Attach the proper stub, if possible
     bool tryAttachStub(JSContext *cx, IonScript *ion, HandleObject obj,

js/src/jit/MIR.h

@@ -6687,7 +6687,6 @@ class MGetPropertyCache
 {
     CompilerRootPropertyName name_;
     bool idempotent_;
-    bool allowGetters_;
     bool monitoredResult_;
 
     CacheLocationList location_;
@@ -6698,7 +6697,6 @@ class MGetPropertyCache
       : MUnaryInstruction(obj),
         name_(name),
         idempotent_(false),
-        allowGetters_(false),
         monitoredResult_(monitoredResult),
         location_(),
         inlinePropertyTable_(nullptr)
@@ -6746,15 +6744,9 @@ class MGetPropertyCache
         idempotent_ = true;
         setMovable();
     }
-    bool allowGetters() const {
-        return allowGetters_;
-    }
     bool monitoredResult() const {
         return monitoredResult_;
     }
-    void setAllowGetters() {
-        allowGetters_ = true;
-    }
     CacheLocationList &location() {
         return location_;
     }