[concurrency] IRGen:: do ptrauth for hop_to_executor

Sign the resume-function pointer which is stored in AsyncTask.ResumeTask

Author: eeckstein

include/swift/AST/IRGenOptions.h

@@ -143,6 +143,9 @@ struct PointerAuthOptions : clang::PointerAuthOptions {
 
   /// The function to call to resume running in the parent context.
   PointerAuthSchema AsyncContextResume;
+
+  /// The resume function stored in AsyncTask.
+  PointerAuthSchema TaskResumeFunction;
 };
 
 enum class JITDebugArtifact : unsigned {

lib/IRGen/GenFunc.cpp

@@ -2462,7 +2462,16 @@ IRGenFunction::createAsyncDispatchFn(const FunctionPointer &fnPtr,
 
 void IRGenFunction::emitSuspensionPoint(llvm::Value *toExecutor,
                                         llvm::Value *asyncResume) {
-  // TODO: pointerauth
+                                        
+  llvm::Value *task = getAsyncTask();
+  llvm::Value *callableResume = asyncResume;
+                                        
+  if (auto schema = IGM.getOptions().PointerAuth.TaskResumeFunction) {
+    auto *resumeAddr = Builder.CreateStructGEP(task, 4);
+    auto authInfo = PointerAuthInfo::emit(
+        *this, schema, resumeAddr, PointerAuthEntity());
+    callableResume = emitPointerAuthSign(*this, asyncResume, authInfo);
+  }
 
   // Setup the suspend point.
   SmallVector<llvm::Value *, 8> arguments;
@@ -2474,10 +2483,10 @@ void IRGenFunction::emitSuspensionPoint(llvm::Value *toExecutor,
   arguments.push_back(
       Builder.CreateBitOrPointerCast(suspendFn, IGM.Int8PtrTy));
 
-  arguments.push_back(asyncResume);
+  arguments.push_back(callableResume);
   arguments.push_back(
       Builder.CreateBitOrPointerCast(toExecutor, getAsyncExecutor()->getType()));
-  arguments.push_back(getAsyncTask());
+  arguments.push_back(task);
   arguments.push_back(getAsyncExecutor());
   arguments.push_back(getAsyncContext());
 

lib/IRGen/IRGen.cpp

@@ -696,6 +696,10 @@ static void setPointerAuthOptions(PointerAuthOptions &opts,
   opts.AsyncContextResume =
       PointerAuthSchema(codeKey, /*address*/ true, Discrimination::Constant,
                         SpecialPointerAuthDiscriminators::AsyncContextResume);
+
+  opts.TaskResumeFunction =
+      PointerAuthSchema(codeKey, /*address*/ true, Discrimination::Constant,
+                        SpecialPointerAuthDiscriminators::TaskResumeFunction);
 }
 
 std::unique_ptr<llvm::TargetMachine>

test/IRGen/async/hop_to_executor.sil

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -enable-experimental-concurrency -primary-file %s -module-name=test -disable-llvm-optzns -disable-swift-specific-llvm-optzns -emit-ir -sil-verify-all | %FileCheck %s
+// RUN: %target-swift-frontend -enable-experimental-concurrency -primary-file %s -module-name=test -disable-llvm-optzns -disable-swift-specific-llvm-optzns -emit-ir -sil-verify-all | %FileCheck %s --check-prefix=CHECK --check-prefix=CHECK-%target-cpu
 
 // REQUIRES: concurrency
 
@@ -15,12 +15,21 @@ final actor class MyActor {
 }
 
 // CHECK-LABEL: define{{.*}} void @test_simple(%swift.task* %0, %swift.executor* %1, %swift.context* %2)
+// CHECK: [[TASK_LOC:%[0-9]+]] = alloca %swift.task*
 // CHECK: [[CTX:%[0-9]+]] = bitcast %swift.context* %2
 // CHECK: [[ACTOR_ADDR:%[0-9]+]] = getelementptr {{.*}} [[CTX]], i32 0, i32 6
 // CHECK: [[ACTOR:%[0-9]+]] = load %T4test7MyActorC*, %T4test7MyActorC** [[ACTOR_ADDR]]
 // CHECK: [[RESUME:%[0-9]+]] = call i8* @llvm.coro.async.resume()
+// CHECK: [[TASK:%[0-9]+]] = load %swift.task*, %swift.task** [[TASK_LOC]]
+// CHECK-arm64e: [[RESUME_ADDR:%[0-9]+]]     = getelementptr inbounds %swift.task, %swift.task* [[TASK]], i32 0, i32 4
+// CHECK-arm64e: [[RESUME_ADDR_INT:%[0-9]+]] = ptrtoint i8** [[RESUME_ADDR]] to i64
+// CHECK-arm64e: [[PTRAUTH_BLEND:%[0-9]+]]   = call i64 @llvm.ptrauth.blend.i64(i64 [[RESUME_ADDR_INT]], i64 11330)
+// CHECK-arm64e: [[RESUME_INT:%[0-9]+]]      = ptrtoint i8* [[RESUME]] to i64
+// CHECK-arm64e: [[SIGNED_INT:%[0-9]+]]      = call i64 @llvm.ptrauth.sign.i64(i64 [[RESUME_INT]], i32 0, i64 [[PTRAUTH_BLEND]])
+// CHECK-arm64e: [[SIGNED_RESUME:%[0-9]+]]   = inttoptr i64 [[SIGNED_INT]] to i8*
 // CHECK: [[CAST_ACTOR:%[0-9]+]] = bitcast %T4test7MyActorC* [[ACTOR]] to %swift.executor*
-// CHECK: call {{.*}} @llvm.coro.suspend.async(i8* [[RESUME]], i8* bitcast (i8* (i8*)* @__swift_async_resume_get_context to i8*), i8* bitcast (void (i8*, %swift.executor*, %swift.task*, %swift.executor*, %swift.context*)* @__swift_suspend_point to i8*), i8* [[RESUME]], %swift.executor* [[CAST_ACTOR]], %swift.task* {{%[0-9]+}}, %swift.executor* {{%[0-9]+}}, %swift.context* {{%[0-9]+}})
+// CHECK-x86_64: call {{.*}} @llvm.coro.suspend.async(i8* [[RESUME]], i8* bitcast (i8* (i8*)* @__swift_async_resume_get_context to i8*), i8* bitcast (void (i8*, %swift.executor*, %swift.task*, %swift.executor*, %swift.context*)* @__swift_suspend_point to i8*), i8* [[RESUME]], %swift.executor* [[CAST_ACTOR]], %swift.task* [[TASK]], %swift.executor* {{%[0-9]+}}, %swift.context* {{%[0-9]+}})
+// CHECK-arm64e: call {{.*}} @llvm.coro.suspend.async(i8* [[SIGNED_RESUME]], i8* bitcast (i8* (i8*)* @__swift_async_resume_get_context to i8*), i8* bitcast (void (i8*, %swift.executor*, %swift.task*, %swift.executor*, %swift.context*)* @__swift_suspend_point to i8*), i8* [[SIGNED_RESUME]], %swift.executor* [[CAST_ACTOR]], %swift.task* [[TASK]], %swift.executor* {{%[0-9]+}}, %swift.context* {{%[0-9]+}})
 sil @test_simple : $@convention(method) @async (@guaranteed MyActor) -> () {
 bb0(%0 : $MyActor):
   hop_to_executor %0 : $MyActor