From bc81d231027c6540ed12305d7bf88aa2b647c188 Mon Sep 17 00:00:00 2001
From: Arnold Schwaighofer <aschwaighofer@apple.com>
Date: Sat, 7 Oct 2023 07:26:38 -0700
Subject: [PATCH] IRGen: Mark async intrinsic helper functions as always inline

github.com/apple/swift/issues/68708
rdar://115905828
---
 lib/IRGen/GenFunc.cpp          | 6 +++++-
 lib/IRGen/IRGen.cpp            | 2 ++
 test/DebugInfo/async-let.swift | 8 ++++----
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/lib/IRGen/GenFunc.cpp b/lib/IRGen/GenFunc.cpp
index 9a003eea85117..5c08a5a944a23 100644
--- a/lib/IRGen/GenFunc.cpp
+++ b/lib/IRGen/GenFunc.cpp
@@ -2529,6 +2529,7 @@ IRGenFunction::createAsyncDispatchFn(const FunctionPointer &fnPtr,
                              llvm::StringRef(name), &IGM.Module);
   dispatch->setCallingConv(IGM.SwiftAsyncCC);
   dispatch->setDoesNotThrow();
+  dispatch->addFnAttr(llvm::Attribute::AlwaysInline);
   IRGenFunction dispatchIGF(IGM, dispatch);
   // Don't emit debug info if we are generating a function for the prologue.
   if (IGM.DebugInfo && Builder.getCurrentDebugLocation())
@@ -2581,13 +2582,15 @@ void IRGenFunction::emitSuspensionPoint(Explosion &toExecutor,
 
 llvm::Function *IRGenFunction::getOrCreateResumeFromSuspensionFn() {
   auto name = "__swift_async_resume_get_context";
-  return cast<llvm::Function>(IGM.getOrCreateHelperFunction(
+  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*/));
+  fn->addFnAttr(llvm::Attribute::AlwaysInline);
+  return fn;
 }
 
 llvm::Function *IRGenFunction::createAsyncSuspendFn() {
@@ -2612,6 +2615,7 @@ llvm::Function *IRGenFunction::createAsyncSuspendFn() {
                              name, &IGM.Module);
   suspendFn->setCallingConv(IGM.SwiftAsyncCC);
   suspendFn->setDoesNotThrow();
+  suspendFn->addFnAttr(llvm::Attribute::AlwaysInline);
   IRGenFunction suspendIGF(IGM, suspendFn);
   if (IGM.DebugInfo)
     IGM.DebugInfo->emitOutlinedFunction(suspendIGF, suspendFn,
diff --git a/lib/IRGen/IRGen.cpp b/lib/IRGen/IRGen.cpp
index 75ac1445794a6..0f5315ff42fff 100644
--- a/lib/IRGen/IRGen.cpp
+++ b/lib/IRGen/IRGen.cpp
@@ -263,6 +263,8 @@ void swift::performLLVMOptimizations(const IRGenOptions &Opts,
                                           OptimizationLevel Level) {
       if (Level != OptimizationLevel::O0)
         MPM.addPass(createModuleToFunctionPassAdaptor(SwiftARCContractPass()));
+      if (Level == OptimizationLevel::O0)
+        MPM.addPass(AlwaysInlinerPass());
     });
   }
 
diff --git a/test/DebugInfo/async-let.swift b/test/DebugInfo/async-let.swift
index 627397b2d0259..835f3a23260c4 100644
--- a/test/DebugInfo/async-let.swift
+++ b/test/DebugInfo/async-let.swift
@@ -8,16 +8,16 @@ public actor Alice {
   let bob = Bob()
 
   // CHECK: define {{.*}}$s1M5AliceC4callyyYaFTY0_{{.*}} !dbg ![[SCOPE0:[0-9]+]]
-  // CHECK: call ptr @__swift_async_resume_get_context{{.*}}!dbg ![[HOP0:[0-9]+]]
+  // CHECK:   load ptr, ptr {{.*}} !dbg ![[HOP0:[0-9]+]]
 
   // CHECK: define {{.*}}$s1M5AliceC4callyyYaFTY1_{{.*}} !dbg ![[SCOPE1:[0-9]+]]
-  // CHECK: call ptr @__swift_async_resume_get_context{{.*}}!dbg ![[HOP1:[0-9]+]]
+  // CHECK:   load ptr, ptr {{.*}} !dbg ![[HOP1:[0-9]+]]
 
   // CHECK: define {{.*}}$s1M5AliceC4callyyYaFSiyYaYbcfu_TY0_{{.*}} !dbg ![[LET_SCOPE0:[0-9]+]]
-  // CHECK: call ptr @__swift_async_resume_get_context{{.*}}!dbg ![[LET_HOP0:[0-9]+]]
+  // CHECK:   load ptr, ptr {{.*}} !dbg ![[LET_HOP0:[0-9]+]]
 
   // CHECK: define {{.*}}$s1M5AliceC4callyyYaFSiyYaYbcfu_TY2_{{.*}} !dbg ![[LET_SCOPE1:[0-9]+]]
-  // CHECK: call ptr @__swift_async_resume_get_context{{.*}}!dbg ![[LET_HOP1:[0-9]+]]
+  // CHECK:   load ptr, ptr {{.*}} !dbg ![[LET_HOP1:[0-9]+]]
   public func call() async {
     // CHECK: ![[SCOPE0]] = distinct !DISubprogram({{.*}}line: [[@LINE-1]]
     // CHECK: ![[HOP0]] = !DILocation(line: [[@LINE-2]], column: 15