Bug 1277562 - Part 12: Get rid of Tier::TBD. r=luke

--HG--
extra : rebase_source : 7f9b33af91e874e8868cb9cb28475dca601bf4e0
extra : intermediate-source : 83bb4f9bda591f62a798979e67aff0a099de4d99
extra : source : 71377c4e714e0991f5d6ac7630f142b5fb6f1fe4

js/src/wasm/WasmCode.cpp

@@ -531,8 +531,6 @@ Metadata::metadata(Tier t) const
         if (hasTier2())
             return *metadata2_;
         MOZ_CRASH("No metadata at this tier");
-      case Tier::TBD:
-        return *metadata1_;
       default:
         MOZ_CRASH();
     }
@@ -552,8 +550,6 @@ Metadata::metadata(Tier t)
         if (hasTier2())
             return *metadata2_;
         MOZ_CRASH("No metadata at this tier");
-      case Tier::TBD:
-        return *metadata1_;
       default:
         MOZ_CRASH();
     }
@@ -715,6 +711,14 @@ Code::stableTier() const
     return segment1_->tier();
 }
 
+Tier
+Code::bestTier() const
+{
+    if (hasTier2())
+        return segment2_->tier();
+    return segment1_->tier();
+}
+
 const CodeSegment&
 Code::segment(Tier tier) const
 {
@@ -729,8 +733,6 @@ Code::segment(Tier tier) const
         if (hasTier2())
             return *segment2_;
         MOZ_CRASH("No code segment at this tier");
-      case Tier::TBD:
-        return *segment1_;
       default:
         MOZ_CRASH();
     }

js/src/wasm/WasmCode.h

@@ -466,7 +466,8 @@ class Code : public ShareableBase<Code>
     Tiers tiers() const;
     bool hasTier(Tier t) const;
 
-    Tier stableTier() const;
+    Tier stableTier() const;    // This is stable during a run
+    Tier bestTier() const;      // This may transition from Baseline -> Ion at any time
 
     const CodeSegment& segment(Tier tier) const;
     const MetadataTier& metadata(Tier tier) const { return metadata_->metadata(tier); }

js/src/wasm/WasmInstance.cpp

@@ -127,7 +127,7 @@ bool
 Instance::callImport(JSContext* cx, uint32_t funcImportIndex, unsigned argc, const uint64_t* argv,
                      MutableHandleValue rval)
 {
-    Tier tier = Tier::TBD;
+    Tier tier = code().bestTier();
 
     const FuncImport& fi = metadata(tier).funcImports[funcImportIndex];
 
@@ -350,8 +350,7 @@ Instance::Instance(JSContext* cx,
     tlsData()->instance = this;
     tlsData()->addressOfContext = (JSContext**)object->zone()->group()->addressOfOwnerContext();
 
-    Tier callerTier = Tier::TBD;
-    Tier calleeTier = Tier::TBD;
+    Tier callerTier = code_->bestTier();
 
     for (size_t i = 0; i < metadata(callerTier).funcImports.length(); i++) {
         HandleFunction f = funcImports[i];
@@ -359,8 +358,9 @@ Instance::Instance(JSContext* cx,
         FuncImportTls& import = funcImportTls(fi);
         if (!isAsmJS() && IsExportedWasmFunction(f)) {
             WasmInstanceObject* calleeInstanceObj = ExportedFunctionToInstanceObject(f);
-            const CodeRange& codeRange = calleeInstanceObj->getExportedFunctionCodeRange(f, calleeTier);
             Instance& calleeInstance = calleeInstanceObj->instance();
+            Tier calleeTier = calleeInstance.code().bestTier();
+            const CodeRange& codeRange = calleeInstanceObj->getExportedFunctionCodeRange(f, calleeTier);
             import.tls = calleeInstance.tlsData();
             import.code = calleeInstance.codeBase(calleeTier) + codeRange.funcNormalEntry();
             import.baselineScript = nullptr;
@@ -503,6 +503,8 @@ Instance::tracePrivate(JSTracer* trc)
     MOZ_ASSERT(!gc::IsAboutToBeFinalized(&object_));
     TraceEdge(trc, &object_, "wasm instance object");
 
+    // OK to just do one tier here; though the tiers have different funcImports
+    // tables, they share the tls object.
     for (const FuncImport& fi : metadata(code().stableTier()).funcImports)
         TraceNullableEdge(trc, &funcImportTls(fi).obj, "wasm import");
 
@@ -561,7 +563,7 @@ Instance::callExport(JSContext* cx, uint32_t funcIndex, CallArgs args)
     // If there has been a moving grow, this Instance should have been notified.
     MOZ_RELEASE_ASSERT(!memory_ || tlsData()->memoryBase == memory_->buffer().dataPointerEither());
 
-    Tier tier = Tier::TBD;
+    Tier tier = code().bestTier();
 
     const FuncExport& func = metadata(tier).lookupFuncExport(funcIndex);
 
@@ -820,9 +822,10 @@ Instance::onMovingGrowTable()
 void
 Instance::deoptimizeImportExit(uint32_t funcImportIndex)
 {
-    const FuncImport& fi = metadata(code().stableTier()).funcImports[funcImportIndex];
+    Tier t = code().bestTier();
+    const FuncImport& fi = metadata(t).funcImports[funcImportIndex];
     FuncImportTls& import = funcImportTls(fi);
-    import.code = codeBase(Tier::TBD) + fi.interpExitCodeOffset();
+    import.code = codeBase(t) + fi.interpExitCodeOffset();
     import.baselineScript = nullptr;
 }
 

js/src/wasm/WasmJS.cpp

@@ -1772,7 +1772,6 @@ WasmTableObject::setImpl(JSContext* cx, const CallArgs& args)
     if (value) {
         RootedWasmInstanceObject instanceObj(cx, ExportedFunctionToInstanceObject(value));
         uint32_t funcIndex = ExportedFunctionToFuncIndex(value);
-        Tier tier = Tier::TBD;  // Perhaps the tier that the function is at?
 
 #ifdef DEBUG
         RootedFunction f(cx);
@@ -1781,6 +1780,7 @@ WasmTableObject::setImpl(JSContext* cx, const CallArgs& args)
 #endif
 
         Instance& instance = instanceObj->instance();
+        Tier tier = instance.code().bestTier();
         const FuncExport& funcExport = instance.metadata(tier).lookupFuncExport(funcIndex);
         const CodeRange& codeRange = instance.metadata(tier).codeRanges[funcExport.codeRangeIndex()];
         void* code = instance.codeBase(tier) + codeRange.funcTableEntry();

js/src/wasm/WasmModule.cpp

@@ -168,8 +168,6 @@ LinkData::linkData(Tier tier) const
         if (hasTier2())
             return *linkData2_;
         MOZ_CRASH("No linkData at this tier");
-      case Tier::TBD:
-        return *linkData1_;
       default:
         MOZ_CRASH();
     }
@@ -189,8 +187,6 @@ LinkData::linkData(Tier tier)
         if (hasTier2())
             return *linkData2_;
         MOZ_CRASH("No linkData at this tier");
-      case Tier::TBD:
-        return *linkData1_;
       default:
         MOZ_CRASH();
     }
@@ -630,7 +626,7 @@ Module::initSegments(JSContext* cx,
     Instance& instance = instanceObj->instance();
     const SharedTableVector& tables = instance.tables();
 
-    Tier tier = Tier::TBD;
+    Tier tier = code().bestTier();
 
     // Perform all error checks up front so that this function does not perform
     // partial initialization if an error is reported.
@@ -680,9 +676,9 @@ Module::initSegments(JSContext* cx,
 
                 HandleFunction f = funcImports[funcIndex];
                 WasmInstanceObject* exportInstanceObj = ExportedFunctionToInstanceObject(f);
-                Tier exportTier = Tier::TBD;
-                const CodeRange& cr = exportInstanceObj->getExportedFunctionCodeRange(f, exportTier);
                 Instance& exportInstance = exportInstanceObj->instance();
+                Tier exportTier = exportInstance.code().bestTier();
+                const CodeRange& cr = exportInstanceObj->getExportedFunctionCodeRange(f, exportTier);
                 table.set(offset + i, exportInstance.codeBase(exportTier) + cr.funcTableEntry(), exportInstance);
             } else {
                 const CodeRange& cr = codeRanges[seg.elemCodeRangeIndices(tier)[i]];

js/src/wasm/WasmTypes.h

@@ -360,8 +360,6 @@ enum class Tier
     Debug = Baseline,
     Ion,
     Serialized = Ion,
-
-    TBD      // A placeholder while tiering is being implemented};
 };
 
 // The CompileMode controls how compilation of a module is performed (notably,
@@ -757,10 +755,6 @@ struct ElemSegment
 
     Uint32Vector& elemCodeRangeIndices(Tier t) {
         switch (t) {
-          case Tier::TBD:
-            if (elemCodeRangeIndices1_.length() > 0)
-                return elemCodeRangeIndices1_;
-            return elemCodeRangeIndices2_;
           case Tier::Baseline:
             return elemCodeRangeIndices1_;
           case Tier::Ion:
@@ -772,10 +766,6 @@ struct ElemSegment
 
     const Uint32Vector& elemCodeRangeIndices(Tier t) const {
         switch (t) {
-          case Tier::TBD:
-            if (elemCodeRangeIndices1_.length() > 0)
-                return elemCodeRangeIndices1_;
-            return elemCodeRangeIndices2_;
           case Tier::Baseline:
             return elemCodeRangeIndices1_;
           case Tier::Ion: