First draft of the sh4 port

src/platform-linux.cc

Index: src/platform-linux.cc
diff --git a/src/platform-linux.cc b/src/platform-linux.cc
index ec48d6305e3de2ea4b51f0571a1c7a83bb0ae619..665ab77691adb47e175a7bd94722f80feb91aa1c 100644
--- a/src/platform-linux.cc
+++ b/src/platform-linux.cc
@@ -284,6 +284,21 @@ bool OS::MipsCpuHasFeature(CpuFeature feature) {
 #endif  // def __mips__
 
 
+#ifdef __sh__
+bool OS::SHCpuHasFeature(CpuFeature feature) {
+  switch (feature) {
+    case FPU:
+      // Assume FPU is always active.
+      // All supported SH4 implementation feature it
+      return true;
+    default:
+      UNREACHABLE();
+  }
+  return false;
+}
+#endif  // def __sh__
+
+
 int OS::ActivationFrameAlignment() {
 #ifdef V8_TARGET_ARCH_ARM
   // On EABI ARM targets this is required for fp correctness in the
@@ -291,6 +306,8 @@ int OS::ActivationFrameAlignment() {
   return 8;
 #elif V8_TARGET_ARCH_MIPS
   return 8;
+#elif V8_TARGET_ARCH_SH4
+  return 4;
 #endif
   // With gcc 4.4 the tree vectorization optimizer can generate code
   // that requires 16 byte alignment such as movdqa on x86.
@@ -409,6 +426,8 @@ void OS::DebugBreak() {
 # endif
 #elif defined(__mips__)
   asm("break");
+#elif defined(__sh__)
+  asm("ldtlb");
 #else
   asm("int $3");
 #endif
@@ -1069,9 +1088,13 @@ static void ProfilerSignalHandler(int signal, siginfo_t* info, void* context) {
 #endif  // defined(__GLIBC__) && !defined(__UCLIBC__) &&
         // (__GLIBC__ < 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ <= 3))
 #elif V8_HOST_ARCH_MIPS
+  sample.pc = reinterpret_cast<Address>(mcontext.pc);
+  sample.sp = reinterpret_cast<Address>(mcontext.gregs[29]);
+  sample.fp = reinterpret_cast<Address>(mcontext.gregs[30]);
+#elif defined(V8_HOST_ARCH_SH4)
   sample->pc = reinterpret_cast<Address>(mcontext.pc);
-  sample->sp = reinterpret_cast<Address>(mcontext.gregs[29]);
-  sample->fp = reinterpret_cast<Address>(mcontext.gregs[30]);
+  sample->sp = reinterpret_cast<Address>(mcontext.gregs[R15]);
+  sample->fp = reinterpret_cast<Address>(mcontext.gregs[R14]);
 #endif  // V8_HOST_ARCH_*
   sampler->SampleStack(sample);
   sampler->Tick(sample);