Added slow_assert macro and flag for slow development assertions in the VM.

runtime/platform/assert.h

Index: runtime/platform/assert.h
diff --git a/runtime/platform/assert.h b/runtime/platform/assert.h
index 3ad928c9296825d91c88eb9ec6dfce59ae8c9ff8..0e3e7148f8d597299eee6a598a78863b3f8622c4 100644
--- a/runtime/platform/assert.h
+++ b/runtime/platform/assert.h
@@ -256,8 +256,13 @@ void DynamicAssertionHelper::NotNull(const T p) {
 
 // DEBUG_ASSERT allows identifiers in condition to be undeclared in release
 // mode.
-#define DEBUG_ASSERT(cond)                                                     \
-  if (!(cond)) dart::Assert(__FILE__, __LINE__).Fail("expected: %s", #cond);
+#define DEBUG_ASSERT(cond) ASSERT(cond)
+
+// SLOW_ASSERT is used for slow assertion code and disabled by default.
+#define SLOW_ASSERT(cond)                                                      \
+  do {                                                                         \
+    if (FLAG_slow_assert) ASSERT(cond);                                 \

[Kevin Millikin (Google), 2012/10/01 10:53:25]

Align the \.  You can add something like

(defun my-c++-mode-hook ()
  (setq c-backslash-column 79)
  (setq c-backslash-max-column 79))
(add-hook 'c++-mode-hook 'my-c++-mode-hook)

You can also write the one-liner:

#define SLOW_ASSERT(cond) ASSERT(!FLAG_slow_assert || (cond))

[zerny-google, 2012/10/01 11:12:04]

Done.

+  } while (false)
 
 #else  // if defined(DEBUG)
 
@@ -268,6 +273,8 @@ void DynamicAssertionHelper::NotNull(const T p) {
 
 #define DEBUG_ASSERT(cond)
 
+#define SLOW_ASSERT(cond)

[Kevin Millikin (Google), 2012/10/01 10:53:25]

This should probably just expand into ASSERT(cond) so it ensures that cond can
compile.

[zerny-google, 2012/10/01 11:12:04]

Well, in the case of the verification code, it's not there when compiling
release mode.

+
 // The COMPILE_ASSERT macro can be used to verify that a compile time
 // expression is true. For example, you could use it to verify the
 // size of a static array: