Add X32 port into V8

test/cctest/test-lockers.cc

Index: test/cctest/test-lockers.cc
===================================================================
--- test/cctest/test-lockers.cc	(revision 15486)
+++ test/cctest/test-lockers.cc	(working copy)
@@ -246,6 +246,8 @@
 TEST(MultithreadedParallelIsolates) {
 #if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
   const int kNThreads = 10;
+#elif V8_TARGET_ARCH_X32
+  const int kNThreads = 4;

[danno, 2013/07/17 13:33:21]

Why is this special handling of x32 needed? I would think you either want a
"mobile" mode (like and the same as ARM and MIPS) or "desktop" mode (everything
else), so folding into either the = 10 or = 40 case.

[haitao.feng, 2013/07/18 10:04:09]

This is related to the code range feature. We used code range and set it to
256M. When there are 10 threads, they will use at least 2.56G memory when they
are all live.  An alternative solution is to use MAP_32BIT flag when doing mmap
(supported by X32 linux kernel) but the drawback is that we could only use <1G
memory space. Here is the link of this discussion 
https://code.google.com/p/v8/issues/detail?id=2473#c18

 #else
   const int kNThreads = 50;
 #endif
@@ -701,6 +703,8 @@
 TEST(ExtensionsRegistration) {
 #if V8_TARGET_ARCH_ARM || V8_TARGET_ARCH_MIPS
   const int kNThreads = 10;
+#elif V8_TARGET_ARCH_X32

[danno, 2013/07/17 13:33:21]

Why is this special handling of x32 needed? I would think you either want a
"mobile" mode (like and the same as ARM and MIPS) or "desktop" mode (everything
else), so folding into either the = 10 or = 40 case.

+  const int kNThreads = 4;
 #else
   const int kNThreads = 40;
 #endif