Fast algorithm for double->string conversion.

src/checks.h

Index: src/checks.h
===================================================================
--- src/checks.h	(revision 3886)
+++ src/checks.h	(working copy)
@@ -80,6 +80,7 @@
   }
 }
 
+
 // Helper function used by the CHECK_EQ function when given int64_t
 // arguments.  Should not be called directly.
 static inline void CheckEqualsHelper(const char* file, int line,
@@ -102,6 +103,28 @@
 }
 
 
+// Helper function used by the CHECK_EQ function when given uint64_t
+// arguments.  Should not be called directly.
+static inline void CheckEqualsHelper(const char* file, int line,
+                                     const char* expected_source,
+                                     uint64_t expected,
+                                     const char* value_source,
+                                     uint64_t value) {
+  if (expected != value) {
+    // Print int64_t values in hex, as two int32s,
+    // to avoid platform-dependencies.
+    V8_Fatal(file, line,
+             "CHECK_EQ(%s, %s) failed\n#"
+             "   Expected: 0x%08x%08x\n#   Found: 0x%08x%08x",
+             expected_source, value_source,
+             static_cast<uint32_t>(expected >> 32),
+             static_cast<uint32_t>(expected),
+             static_cast<uint32_t>(value >> 32),
+             static_cast<uint32_t>(value));
+  }
+}
+
+
 // Helper function used by the CHECK_NE function when given int
 // arguments.  Should not be called directly.
 static inline void CheckNonEqualsHelper(const char* file,
@@ -200,6 +223,27 @@
 }
 
 
+static inline void CheckNonEqualsHelper(const char* file,
+                                     int line,
+                                     const char* expected_source,
+                                     double expected,
+                                     const char* value_source,
+                                     double value) {
+  // Force values to 64 bit memory to truncate 80 bit precision on IA32.
+  volatile double* exp = new double[1];
+  *exp = expected;
+  volatile double* val = new double[1];
+  *val = value;
+  if (*exp == *val) {
+    V8_Fatal(file, line,
+             "CHECK_NE(%s, %s) failed\n#   Value: %f",
+             expected_source, value_source, *val);
+  }
+  delete[] exp;
+  delete[] val;
+}
+
+
 namespace v8 {
   class Value;
   template <class T> class Handle;