[ast] Remove heap accesses from AST numbering

src/ast/ast-value-factory.h

Index: src/ast/ast-value-factory.h
diff --git a/src/ast/ast-value-factory.h b/src/ast/ast-value-factory.h
index 6f9091bd167d09ae09848101377ef729280f6f73..b471ad5daa58afbd6d4f41422adf5ca6331c54e4 100644
--- a/src/ast/ast-value-factory.h
+++ b/src/ast/ast-value-factory.h
@@ -159,10 +159,7 @@ class AstValue : public ZoneObject {
     return type_ == STRING;
   }
 
-  bool IsNumber() const {
-    return type_ == NUMBER || type_ == NUMBER_WITH_DOT || type_ == SMI ||
-           type_ == SMI_WITH_DOT;
-  }
+  bool IsNumber() const { return IsSmi() || IsHeapNumber(); }
 
   bool ContainsDot() const {
     return type_ == NUMBER_WITH_DOT || type_ == SMI_WITH_DOT;
@@ -174,19 +171,36 @@ class AstValue : public ZoneObject {
   }
 
   double AsNumber() const {
-    if (type_ == NUMBER || type_ == NUMBER_WITH_DOT)
-      return number_;
-    if (type_ == SMI || type_ == SMI_WITH_DOT)
-      return smi_;
+    if (IsHeapNumber()) return number_;
+    if (IsSmi()) return smi_;
     UNREACHABLE();
     return 0;
   }
 
   Smi* AsSmi() const {
-    CHECK(type_ == SMI || type_ == SMI_WITH_DOT);
+    CHECK(IsSmi());
     return Smi::FromInt(smi_);
   }
 
+  bool ToUint32(uint32_t* value) const {
+    if (IsSmi()) {
+      int num = smi_;
+      if (num < 0) return false;
+      *value = static_cast<uint32_t>(num);
+      return true;
+    }
+    if (IsHeapNumber()) {
+      double num = number_;
+      if (num < 0) return false;
+      uint32_t uint_value = FastD2UI(num);
+      if (FastUI2D(uint_value) == num) {
+        *value = uint_value;
+        return true;
+      }

[rmcilroy, 2017/01/13 09:53:57]

You need to be careful to check for minus 0.0 as well. How about making a
variant of IsUint32Double in conversions.h which takes an argument to return the
uint32 value, and just use that here?

[Leszek Swirski, 2017/01/13 10:58:10]

Done, and amended the code in objects-inl.h that I stole to call teh same
function.

+    }
+    return false;
+  }
+
   bool EqualsString(const AstRawString* string) const {
     return type_ == STRING && string_ == string;
   }
@@ -196,6 +210,9 @@ class AstValue : public ZoneObject {
   bool BooleanValue() const;
 
   bool IsSmi() const { return type_ == SMI || type_ == SMI_WITH_DOT; }
+  bool IsHeapNumber() const {
+    return type_ == NUMBER || type_ == NUMBER_WITH_DOT;
+  }
   bool IsFalse() const { return type_ == BOOLEAN && !bool_; }
   bool IsTrue() const { return type_ == BOOLEAN && bool_; }
   bool IsUndefined() const { return type_ == UNDEFINED; }