pull in initial version of compile-arm64.S, to fix arm64 build (untested)

Initial implementation courtesy Joel Dice (@dicej)

src/compile-arm64.S

@@ -23,4 +23,107 @@
 #  define GLOBAL(x) x   
 #endif
 
-#error not implemented
+#define CONTINUATION_NEXT 4
+#define CONTINUATION_ADDRESS 16
+#define CONTINUATION_RETURN_ADDRESS_OFFSET 20
+#define CONTINUATION_FRAME_POINTER_OFFSET 24
+#define CONTINUATION_LENGTH 28
+#define CONTINUATION_BODY 32
+   
+.globl GLOBAL(vmInvoke)
+.align 2
+GLOBAL(vmInvoke):
+  // arguments:
+  //   x0 : thread
+  //   x1 : function
+  //   x2 : arguments
+  //   w3 : argumentFootprint
+  //   w4 : frameSize (not used)
+  //   w5 : returnType
+
+  // allocate frame
+  stp   x29, x30, [sp,#-96]!
+
+  // save callee-saved register values
+  stp   x19, x20, [sp,#16]
+  stp   x21, x22, [sp,#32]
+  stp   x23, x24, [sp,#48]
+  stp   x25, x26, [sp,#64]
+  stp   x27, x28, [sp,#80]
+
+  // save return type
+  str   w5, [sp,#-16]!
+
+  mov   x5, sp
+  str   x5, [x0,#TARGET_THREAD_SCRATCH]
+
+  // copy arguments into place
+  sub   sp, sp, w3
+  mov   x5, #0
+  b     LOCAL(vmInvoke_argumentTest)
+
+LOCAL(vmInvoke_argumentLoop):
+  ldr   x5, [x2, x4]
+  str   x5, [sp, x4]
+  add   x4, x4, #BYTES_PER_WORD
+
+LOCAL(vmInvoke_argumentTest):
+  cmp   x4, x3
+  blt   LOCAL(vmInvoke_argumentLoop)
+
+  // we use x19 to hold the thread pointer, by convention
+  mov   x19, x0
+
+  // load and call function address
+  blr   x1
+
+.globl GLOBAL(vmInvoke_returnAddress)
+.align 2
+GLOBAL(vmInvoke_returnAddress):
+  // restore stack pointer
+  ldr   x5, [x19, #TARGET_THREAD_SCRATCH]
+  mov   sp, x5
+
+  // clear MyThread::stack to avoid confusing another thread calling
+  // java.lang.Thread.getStackTrace on this one.  See
+  // MyProcess::getStackTrace in compile.cpp for details on how we get
+  // a reliable stack trace from a thread that might be interrupted at
+  // any point in its execution.
+  mov  x5, #0
+  str  x5, [x19, #TARGET_THREAD_STACK]
+
+.globl GLOBAL(vmInvoke_safeStack)
+.align 2
+GLOBAL(vmInvoke_safeStack):
+
+#ifdef AVIAN_CONTINUATIONS
+#error todo
+#endif // AVIAN_CONTINUATIONS
+
+  mov   x5, #0
+  str   x5, [x19, #TARGET_THREAD_STACK]
+
+  // restore return type
+  ldr   w5, [sp], #4
+
+  // restore callee-saved register values
+  ldp   x19, x20, [sp,#16]
+  ldp   x21, x22, [sp,#32]
+  ldp   x23, x24, [sp,#48]
+  ldp   x25, x26, [sp,#64]
+  ldp   x27, x28, [sp,#80]
+  ldp   x29, x30, [sp],#96
+
+LOCAL(vmInvoke_return):
+  br    x30
+
+.globl GLOBAL(vmJumpAndInvoke)
+.align 2
+GLOBAL(vmJumpAndInvoke):
+#ifdef AVIAN_CONTINUATIONS
+#error todo
+#else // not AVIAN_CONTINUATIONS
+   // vmJumpAndInvoke should only be called when continuations are
+   // enabled, so we force a crash if we reach here:
+   brk 0
+#endif // not AVIAN_CONTINUATIONS