[wasm] WIP fix arm64 frame alignment.

src/arm64/macro-assembler-arm64.cc

Index: src/arm64/macro-assembler-arm64.cc
diff --git a/src/arm64/macro-assembler-arm64.cc b/src/arm64/macro-assembler-arm64.cc
index 0a605b52d3cb0d145b61a461a8b46f7d8e2ae215..6abc639fb38b6eeca798ed1c1fd35012bef67ffc 100644
--- a/src/arm64/macro-assembler-arm64.cc
+++ b/src/arm64/macro-assembler-arm64.cc
@@ -1355,6 +1355,14 @@ void MacroAssembler::AssertStackConsistency() {
   }
 }
 
+void MacroAssembler::AssertCspAligned() {

[ahaas, 2016/03/29 08:33:58]

Could you let this function return a boolean so that you can call it in a
DCHECK?

[titzer, 2016/03/29 09:10:53]

This method doesn't assert anything in C++ land; it generates an access through
the stack pointer, which functions as an assertion in the generated code.

+  if (emit_debug_code() && use_real_aborts()) {
+    // TODO(titzer): use a real assert for alignment check?
+    UseScratchRegisterScope scope(this);
+    Register temp = scope.AcquireX();
+    ldr(temp, MemOperand(csp));
+  }
+}
 
 void MacroAssembler::AssertFPCRState(Register fpcr) {
   if (emit_debug_code()) {