[wasm] WIP fix arm64 frame alignment.

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index 91900be25c30dabec502028de1401680631509ae..400dcd12d12267d13918d3df57da496230519e03 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -1543,13 +1543,15 @@ void InstructionSelector::VisitCall(Node* node, BasicBlock* handler) {
     buffer.instruction_args.push_back(g.Label(handler));
   }
 
-  // (arm64 only) caller uses JSSP but callee might destroy it.
-  if (descriptor->UseNativeStack() &&
-      !linkage()->GetIncomingDescriptor()->UseNativeStack()) {
-    flags |= CallDescriptor::kRestoreJSSP;
+  bool from_native_stack = linkage()->GetIncomingDescriptor()->UseNativeStack();
+  bool to_native_stack = descriptor->UseNativeStack();
+  if (from_native_stack != to_native_stack) {
+    // (arm64 only) Mismatch in the use of stack pointers. One or the other
+    // has to be restored manually by the code generator.
+    flags |= to_native_stack ? CallDescriptor::kRestoreJSSP
+                             : CallDescriptor::kRestoreCSP;
   }
 
-
   // Select the appropriate opcode based on the call type.
   InstructionCode opcode = kArchNop;
   switch (descriptor->kind()) {