[IRGen] Signed parent async context.

Author: nate-chandler

lib/IRGen/IRGenFunction.cpp

@@ -564,7 +564,13 @@ void IRGenFunction::emitGetAsyncContinuation(SILType resumeTy,
   // TODO: add lifetime with matching lifetime in await_async_continuation
   auto contResumeAddr =
       Builder.CreateStructGEP(continuationContext.getAddress(), 0);
-  Builder.CreateStore(getAsyncContext(),
+  llvm::Value *asyncContextValue = getAsyncContext();
+  if (auto schema = IGM.getOptions().PointerAuth.AsyncContextParent) {
+    auto authInfo = PointerAuthInfo::emit(*this, schema, contResumeAddr,
+                                          PointerAuthEntity());
+    asyncContextValue = emitPointerAuthSign(*this, asyncContextValue, authInfo);
+  }
+  Builder.CreateStore(asyncContextValue,
                       Address(contResumeAddr, pointerAlignment));
   auto contErrResultAddr =
       Builder.CreateStructGEP(continuationContext.getAddress(), 2);

test/IRGen/async/get_async_continuation.sil

@@ -27,7 +27,15 @@ bb0:
 //   Initialize the async  continuation context.
 // CHECK: [[context_addr:%.*]] = getelementptr inbounds %swift.async_continuation_context, %swift.async_continuation_context* [[cont_context]], i32 0, i32 0
 // CHECK: [[ctxt:%.*]] = load %swift.context*, %swift.context** [[ctxt_addr]]
-// CHECK: store %swift.context* [[ctxt]], %swift.context** [[context_addr]]
+
+// CHECK-arm64e: [[ctxt_addr_int:%[0-9]+]] = ptrtoint %swift.context** [[context_addr]] to i64
+// CHECK-arm64e: [[ptrauth_blend:%[0-9]+]]   = call i64 @llvm.ptrauth.blend.i64(i64 [[ctxt_addr_int]], i64 48546)
+// CHECK-arm64e: [[ctxt_int:%[0-9]+]]      = ptrtoint %swift.context* [[ctxt]] to i64
+// CHECK-arm64e: [[signed_int:%[0-9]+]]      = call i64 @llvm.ptrauth.sign.i64(i64 [[ctxt_int]], i32 2, i64 [[ptrauth_blend]])
+// CHECK-arm64e: [[signed_ctxt:%[0-9]+]]   = inttoptr i64 [[signed_int]] to %swift.context*
+// CHECK-arm64e: store %swift.context* [[signed_ctxt]], %swift.context** [[context_addr]]
+// CHECK-x86_64: store %swift.context* [[ctxt]], %swift.context** [[context_addr]]
+
 // CHECK: [[error_addr:%.*]] = getelementptr inbounds %swift.async_continuation_context, %swift.async_continuation_context* [[cont_context]], i32 0, i32 2
 // CHECK: store %swift.error* null, %swift.error** [[error_addr]]
 // CHECK: [[result_addr:%.*]] = getelementptr inbounds %swift.async_continuation_context, %swift.async_continuation_context* [[cont_context]], i32 0, i32 3