First draft of the sh4 port

src/full-codegen.h

Index: src/full-codegen.h
diff --git a/src/full-codegen.h b/src/full-codegen.h
index 89b51f9582b2a3520af96155f3817ca12831ac91..022b7c703eabe018171aae12fd0bc7c705e94dbd 100644
--- a/src/full-codegen.h
+++ b/src/full-codegen.h
@@ -127,6 +127,9 @@ class FullCodeGenerator: public AstVisitor {
   static const int kBackEdgeDistanceUnit = 142;
 #elif V8_TARGET_ARCH_MIPS
   static const int kBackEdgeDistanceUnit = 142;
+#elif V8_TARGET_ARCH_SH4
+  // TODO(STM): what is this for ?

[Jakob Kummerow, 2012/11/07 11:18:24]

For estimating which functions are hot, the profiler divides back edge jump
distances of loops by this value to get a normalized estimate of the amount of
code executed in the loop. The value for ia32 has been chosen arbitrarily, the
values for other platforms are chosen to match the resulting behavior for ia32
(specifically, that a loop generated from the same JS source code is deemed
"hot" after roughly the same number of iterations). As long as you don't support
Crankshaft, you can afford to not care. When you do want optimizations, it
should be safe to pick a value that's roughly in line with the other
architectures, until you get around to brute-force-benchmarking what works best.

[remi.duraffort, 2012/11/07 11:59:26]

Thanks for the exaplnation.
For the moment cranckshaft is not available on sh4.

+  static const int kBackEdgeDistanceUnit = -1;
 #else
 #error Unsupported target architecture.
 #endif