[DebugInfo] Dont generate info for __swift_async_resume_project_conte…

lib/IRGen/GenFunc.cpp

@@ -2590,8 +2590,9 @@ IRGenFunction::emitAsyncResumeProjectContext(llvm::Value *calleeContext) {
 }
 
 llvm::Function *IRGenFunction::getOrCreateResumePrjFn(bool forPrologue) {
-  // The prologue version lacks artificial debug info as this would cause
-  // verification errors when it gets inlined.
+  // Never emit debug info for these alwaysinline functions, as it would create
+  // an inline frame without any user code. These can also be involved in tail
+  // calls, which confuse the debugger.
   auto name = forPrologue ? "__swift_async_resume_project_context_prologue"
                           : "__swift_async_resume_project_context";
   auto Fn = cast<llvm::Function>(IGM.getOrCreateHelperFunction(
@@ -2603,7 +2604,7 @@ llvm::Function *IRGenFunction::getOrCreateResumePrjFn(bool forPrologue) {
         auto callerContext = IGF.emitAsyncResumeProjectContext(addr);
         Builder.CreateRet(callerContext);
       },
-      false /*isNoInline*/, forPrologue));
+      false /*isNoInline*/, true/*for prologue*/));
   Fn->addFnAttr(llvm::Attribute::AlwaysInline);
   return Fn;
 }
@@ -2694,14 +2695,17 @@ void IRGenFunction::emitSuspensionPoint(Explosion &toExecutor,
 }
 
 llvm::Function *IRGenFunction::getOrCreateResumeFromSuspensionFn() {
+  // Never emit debug info for these alwaysinline functions, as it would create
+  // an inline frame without any user code. These can also be involved in tail
+  // calls, which confuse the debugger.
   auto name = "__swift_async_resume_get_context";
   auto fn = cast<llvm::Function>(IGM.getOrCreateHelperFunction(
       name, IGM.Int8PtrTy, {IGM.Int8PtrTy},
       [&](IRGenFunction &IGF) {
         auto &Builder = IGF.Builder;
         Builder.CreateRet(&*IGF.CurFn->arg_begin());
       },
-      false /*isNoInline*/));
+      false /*isNoInline*/, true /*forPrologue*/));
   fn->addFnAttr(llvm::Attribute::AlwaysInline);
   return fn;
 }

test/IRGen/async/no_debug_info_in_projections.sil

@@ -0,0 +1,48 @@
+// RUN: %target-swift-frontend %s -g -emit-irgen | %IRGenFileCheck %s
+
+// We don't want any debug info for these helper functions:
+
+// CHECK: define {{.*}} @__swift_async_resume_project_context
+// CHECK-NOT: !dbg
+// CHECK-SAME: {
+// CHECK: define {{.*}} @__swift_async_resume_get_context
+// CHECK-NOT: !dbg
+// CHECK-SAME: {
+
+sil_stage canonical
+
+import Builtin
+import Swift
+import SwiftShims
+
+@_silgen_name("some_async_func")
+public func some_async_func() async -> Int
+
+func foo() async -> Int
+
+sil_scope 1 {  parent @main : $@convention(c) (Int32, UnsafeMutablePointer<Optional<UnsafeMutablePointer<Int8>>>) -> Int32 }
+
+sil @main : $@convention(c) (Int32, UnsafeMutablePointer<Optional<UnsafeMutablePointer<Int8>>>) -> Int32 {
+bb0(%0 : $Int32, %1 : $UnsafeMutablePointer<Optional<UnsafeMutablePointer<Int8>>>):
+  %2 = integer_literal $Builtin.Int32, 0, scope 1 // user: %3
+  %3 = struct $Int32 (%2 : $Builtin.Int32), scope 1 // user: %4
+  return %3 : $Int32, scope 1                     // id: %4
+}
+
+sil_scope 2 { loc "test.swift":4:6 parent @$s4test3fooSiyYaF : $@convention(thin) @async () -> Int }
+sil_scope 3 { loc "test.swift":5:16 parent 2 }
+sil_scope 4 { loc "test.swift":5:7 parent 2 }
+
+sil @$s4test3fooSiyYaF : $@convention(thin) @async () -> Int {
+bb0:
+  %0 = enum $Optional<Builtin.Executor>, #Optional.none!enumelt, loc * "test.swift":4:6, scope 2 // user: %3
+  // function_ref some_async_func
+  %1 = function_ref @some_async_func : $@convention(thin) @async () -> Int, loc "test.swift":5:22, scope 3 // user: %2
+  %2 = apply %1() : $@convention(thin) @async () -> Int, loc "test.swift":5:22, scope 3 // users: %6, %4
+  hop_to_executor %0 : $Optional<Builtin.Executor>, loc * "test.swift":5:22, scope 3 // id: %3
+  debug_value %2 : $Int, let, name "result", loc "test.swift":5:7, scope 4 // id: %4
+  return %2 : $Int, loc "test.swift":6:3, scope 4 // id: %13
+}
+
+
+sil @some_async_func : $@convention(thin) @async () -> Int