1 files changed, 105 insertions, 0 deletions
diff --git a/js/src/jit/KnownClass.cpp b/js/src/jit/KnownClass.cpp
new file mode 100644
index 0000000000..46a59912eb
--- /dev/null
+++ b/js/src/jit/KnownClass.cpp
@@ -0,0 +1,105 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * vim: set ts=8 sts=2 et sw=2 tw=80:
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "jit/KnownClass.h"
+
+#include "jit/MIR.h"
+#include "vm/ArrayObject.h"
+#include "vm/Iteration.h"
+#include "vm/JSFunction.h"
+#include "vm/PlainObject.h"  // js::PlainObject
+#include "vm/RegExpObject.h"
+
+using namespace js;
+using namespace js::jit;
+
+KnownClass jit::GetObjectKnownClass(const MDefinition* def) {
+  MOZ_ASSERT(def->type() == MIRType::Object);
+
+  switch (def->op()) {
+    case MDefinition::Opcode::NewArray:
+    case MDefinition::Opcode::NewArrayDynamicLength:
+      return KnownClass::Array;
+
+    case MDefinition::Opcode::NewObject:
+    case MDefinition::Opcode::CreateThis:
+    case MDefinition::Opcode::CreateThisWithTemplate:
+      return KnownClass::PlainObject;
+
+    case MDefinition::Opcode::Lambda:
+    case MDefinition::Opcode::LambdaArrow:
+    case MDefinition::Opcode::FunctionWithProto:
+      return KnownClass::Function;
+
+    case MDefinition::Opcode::RegExp:
+      return KnownClass::RegExp;
+
+    case MDefinition::Opcode::NewIterator:
+      switch (def->toNewIterator()->type()) {
+        case MNewIterator::ArrayIterator:
+          return KnownClass::ArrayIterator;
+        case MNewIterator::StringIterator:
+          return KnownClass::StringIterator;
+        case MNewIterator::RegExpStringIterator:
+          return KnownClass::RegExpStringIterator;
+      }
+      MOZ_CRASH("unreachable");
+
+    case MDefinition::Opcode::Phi: {
+      if (def->numOperands() == 0) {
+        return KnownClass::None;
+      }
+
+      MDefinition* op = def->getOperand(0);
+      // Check for Phis to avoid recursion for now.
+      if (op->isPhi()) {
+        return KnownClass::None;
+      }
+
+      KnownClass known = GetObjectKnownClass(op);
+      if (known == KnownClass::None) {
+        return KnownClass::None;
+      }
+
+      for (size_t i = 1; i < def->numOperands(); i++) {
+        op = def->getOperand(i);
+        if (op->isPhi() || GetObjectKnownClass(op) != known) {
+          return KnownClass::None;
+        }
+      }
+
+      return known;
+    }
+
+    default:
+      break;
+  }
+
+  return KnownClass::None;
+}
+
+const JSClass* jit::GetObjectKnownJSClass(const MDefinition* def) {
+  switch (GetObjectKnownClass(def)) {
+    case KnownClass::PlainObject:
+      return &PlainObject::class_;
+    case KnownClass::Array:
+      return &ArrayObject::class_;
+    case KnownClass::Function:
+      return &JSFunction::class_;
+    case KnownClass::RegExp:
+      return &RegExpObject::class_;
+    case KnownClass::ArrayIterator:
+      return &ArrayIteratorObject::class_;
+    case KnownClass::StringIterator:
+      return &StringIteratorObject::class_;
+    case KnownClass::RegExpStringIterator:
+      return &RegExpStringIteratorObject::class_;
+    case KnownClass::None:
+      break;
+  }
+
+  return nullptr;
+}