[Coroutines] Set presplit attribute in Clang instead of CoroEarly pass

Presplit coroutines cannot be inlined. During AlwaysInliner we check if a function is a presplit coroutine, if so we skip inlining.
The presplit coroutine attributes are set in CoroEarly pass.
However in O0 pipeline, AlwaysInliner runs before CoroEarly, so the attribute isn't set yet and will still inline the coroutine.
This causes Clang to crash: https://bugs.llvm.org/show_bug.cgi?id=49920

To fix this, we set the attributes in the Clang front-end instead of in CoroEarly pass.

Reviewed By: rjmccall, ChuanqiXu

Differential Revision: https://reviews.llvm.org/D100282

clang/lib/CodeGen/CGCoroutine.cpp

@@ -558,6 +558,8 @@ void CodeGenFunction::EmitCoroutineBody(const CoroutineBodyStmt &S) {
   CurCoro.Data->SuspendBB = RetBB;
   assert(ShouldEmitLifetimeMarkers &&
          "Must emit lifetime intrinsics for coroutines");
+  // CORO_PRESPLIT_ATTR = UNPREPARED_FOR_SPLIT
+  CurFn->addFnAttr("coroutine.presplit", "0");
 
   // Backend is allowed to elide memory allocations, to help it, emit
   // auto mem = coro.alloc() ? 0 : ... allocation code ...;

clang/test/CodeGenCoroutines/coro-always-inline-resume.cpp

@@ -0,0 +1,54 @@
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
+// RUN:   -fexperimental-new-pass-manager -O0 %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
+// RUN:   -fexperimental-new-pass-manager -fno-inline -O0 %s -o - | FileCheck %s
+
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
+// RUN:   -O0 %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
+// RUN:   -fno-inline -O0 %s -o - | FileCheck %s
+
+namespace std {
+namespace experimental {
+
+struct handle {};
+
+struct awaitable {
+  bool await_ready() noexcept { return true; }
+  // CHECK-NOT: await_suspend
+  inline void __attribute__((__always_inline__)) await_suspend(handle) noexcept {}
+  bool await_resume() noexcept { return true; }
+};
+
+template <typename T>
+struct coroutine_handle {
+  static handle from_address(void *address) noexcept { return {}; }
+};
+
+template <typename T = void>
+struct coroutine_traits {
+  struct promise_type {
+    awaitable initial_suspend() { return {}; }
+    awaitable final_suspend() noexcept { return {}; }
+    void return_void() {}
+    T get_return_object() { return T(); }
+    void unhandled_exception() {}
+  };
+};
+} // namespace experimental
+} // namespace std
+
+// CHECK-LABEL: @_Z3foov
+// CHECK-LABEL: entry:
+// CHECK-NEXT: %this.addr.i{{[0-9]*}} = alloca %"struct.std::experimental::awaitable"*, align 8
+// CHECK-NEXT: %this.addr.i{{[0-9]*}} = alloca %"struct.std::experimental::awaitable"*, align 8
+// CHECK: [[CAST0:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
+// CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 8, i8* [[CAST0]])
+// CHECK: [[CAST1:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
+// CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 8, i8* [[CAST1]])
+
+// CHECK: [[CAST2:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
+// CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 8, i8* [[CAST2]])
+// CHECK: [[CAST3:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
+// CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 8, i8* [[CAST3]])
+void foo() { co_return; }

clang/test/CodeGenCoroutines/coro-always-inline.cpp

@@ -1,54 +1,68 @@
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
-// RUN:   -fexperimental-new-pass-manager -O0 %s -o - | FileCheck %s
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
-// RUN:   -fexperimental-new-pass-manager -fno-inline -O0 %s -o - | FileCheck %s
+// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -std=c++2a %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s
+// RUN: %clang -cc1 -triple x86_64-unknown-linux-gnu -std=c++2a %s -emit-llvm -disable-llvm-passes -o - | opt -always-inline -S | FileCheck --check-prefix=INLINE %s
 
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
-// RUN:   -O0 %s -o - | FileCheck %s
-// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -emit-llvm -fcoroutines-ts \
-// RUN:   -fno-inline -O0 %s -o - | FileCheck %s
+#include "Inputs/coroutine.h"
 
-namespace std {
-namespace experimental {
+namespace coro = std::experimental::coroutines_v1;
 
-struct handle {};
+class task {
+public:
+  class promise_type {
+  public:
+    task get_return_object() noexcept;
+    coro::suspend_always initial_suspend() noexcept;
+    void return_void() noexcept;
+    void unhandled_exception() noexcept;
 
-struct awaitable {
-  bool await_ready() noexcept { return true; }
-  // CHECK-NOT: await_suspend
-  inline void __attribute__((__always_inline__)) await_suspend(handle) noexcept {}
-  bool await_resume() noexcept { return true; }
-};
+    struct final_awaiter {
+      bool await_ready() noexcept;
+      void await_suspend(coro::coroutine_handle<promise_type> h) noexcept;
+      void await_resume() noexcept;
+    };
 
-template <typename T>
-struct coroutine_handle {
-  static handle from_address(void *address) noexcept { return {}; }
-};
+    final_awaiter final_suspend() noexcept;
 
-template <typename T = void>
-struct coroutine_traits {
-  struct promise_type {
-    awaitable initial_suspend() { return {}; }
-    awaitable final_suspend() noexcept { return {}; }
-    void return_void() {}
-    T get_return_object() { return T(); }
-    void unhandled_exception() {}
+    coro::coroutine_handle<> continuation;
   };
+
+  task(task &&t) noexcept;
+  ~task();
+
+  class awaiter {
+  public:
+    bool await_ready() noexcept;
+    void await_suspend(coro::coroutine_handle<> continuation) noexcept;
+    void await_resume() noexcept;
+
+  private:
+    friend task;
+    explicit awaiter(coro::coroutine_handle<promise_type> h) noexcept;
+    coro::coroutine_handle<promise_type> coro_;
+  };
+
+  awaiter operator co_await() &&noexcept;
+
+private:
+  explicit task(coro::coroutine_handle<promise_type> h) noexcept;
+  coro::coroutine_handle<promise_type> coro_;
 };
-} // namespace experimental
-} // namespace std
 
-// CHECK-LABEL: @_Z3foov
-// CHECK-LABEL: entry:
-// CHECK-NEXT: %this.addr.i{{[0-9]*}} = alloca %"struct.std::experimental::awaitable"*, align 8
-// CHECK-NEXT: %this.addr.i{{[0-9]*}} = alloca %"struct.std::experimental::awaitable"*, align 8
-// CHECK: [[CAST0:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
-// CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 8, i8* [[CAST0]])
-// CHECK: [[CAST1:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
-// CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 8, i8* [[CAST1]])
+task cee();
 
-// CHECK: [[CAST2:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
-// CHECK-NEXT: call void @llvm.lifetime.start.p0i8(i64 8, i8* [[CAST2]])
-// CHECK: [[CAST3:%[0-9]+]] = bitcast %"struct.std::experimental::awaitable"** %this.addr.i{{[0-9]*}} to i8*
-// CHECK-NEXT: call void @llvm.lifetime.end.p0i8(i64 8, i8* [[CAST3]])
-void foo() { co_return; }
+__attribute__((always_inline)) inline task bar() {
+  co_await cee();
+  co_return;
+}
+
+task foo() {
+  co_await bar();
+  co_return;
+}
+
+// check that Clang front-end will tag bar with both alwaysinline and coroutine presplit
+// CHECK:       define linkonce_odr void @_Z3barv({{.*}}) #[[ATTR:[0-9]+]] {{.*}}
+// CHECK:       attributes #[[ATTR]] = { alwaysinline {{.*}} "coroutine.presplit"="0" {{.*}}}
+
+// check that bar is not inlined even it's marked as always_inline
+// INLINE-LABEL: define dso_local void @_Z3foov(
+// INLINE:         call void @_Z3barv(

llvm/lib/Transforms/Coroutines/CoroEarly.cpp

@@ -179,7 +179,6 @@ bool Lowerer::lowerEarlyIntrinsics(Function &F) {
         // with a coroutine attribute.
         if (auto *CII = cast<CoroIdInst>(&I)) {
           if (CII->getInfo().isPreSplit()) {
-            F.addFnAttr(CORO_PRESPLIT_ATTR, UNPREPARED_FOR_SPLIT);
             setCannotDuplicate(CII);
             CII->setCoroutineSelf();
             CoroId = cast<CoroIdInst>(&I);

llvm/test/Transforms/Coroutines/coro-debug-O2.ll

@@ -9,7 +9,7 @@
 ; CHECK: ![[PROMISEVAR_RESUME]] = !DILocalVariable(name: "__promise"
 %promise_type = type { i32, i32, double }
 
-define void @f() !dbg !8 {
+define void @f() "coroutine.presplit"="0" !dbg !8 {
 entry:
     %__promise = alloca %promise_type, align 8
     %0 = bitcast %promise_type* %__promise to i8*

llvm/test/Transforms/Coroutines/coro-debug-frame-variable.ll

@@ -63,7 +63,7 @@
 ; CHECK: ![[IVAR_RESUME]] = !DILocalVariable(name: "i"
 ; CHECK: ![[JVAR_RESUME]] = !DILocalVariable(name: "j"
 ; CHECK: ![[JDBGLOC_RESUME]] = !DILocation(line: 32, column: 7, scope: ![[RESUME_SCOPE]])
-define void @f() {
+define void @f() "coroutine.presplit"="0" {
 entry:
   %__promise = alloca i8, align 8
   %i = alloca i32, align 4

llvm/test/Transforms/Coroutines/coro-split-01.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -S -enable-coroutines -O2 | FileCheck %s
 ; RUN: opt < %s -S -enable-coroutines -passes='default<O2>' | FileCheck %s
 
-define i8* @f() {
+define i8* @f() "coroutine.presplit"="0" {
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %need.dyn.alloc = call i1 @llvm.coro.alloc(token %id)

llvm/test/Transforms/Coroutines/coro-split-recursive.ll

@@ -13,7 +13,7 @@ declare i8 @llvm.coro.suspend(token, i1)
 ; CHECK: call void @foo()
 ; CHECK-LABEL: define {{.*}}void @foo.destroy(
 
-define void @foo() {
+define void @foo() "coroutine.presplit"="0" {
 entry:
   %__promise = alloca i32, align 8
   %0 = bitcast i32* %__promise to i8*

llvm/test/Transforms/Coroutines/ex0.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -enable-coroutines -O2 -preserve-alignment-assumptions-during-inlining=false -S | FileCheck %s
 ; RUN: opt < %s -enable-coroutines -aa-pipeline=basic-aa -passes='default<O2>' -preserve-alignment-assumptions-during-inlining=false -S | FileCheck %s
 
-define i8* @f(i32 %n) {
+define i8* @f(i32 %n) "coroutine.presplit"="0" {
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %size = call i32 @llvm.coro.size.i32()

llvm/test/Transforms/Coroutines/ex1.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -O2 -enable-coroutines -preserve-alignment-assumptions-during-inlining=false -S | FileCheck %s
 ; RUN: opt < %s -aa-pipeline=basic-aa -passes='default<O2>' -enable-coroutines -preserve-alignment-assumptions-during-inlining=false -S | FileCheck %s
 
-define i8* @f(i32 %n) {
+define i8* @f(i32 %n) "coroutine.presplit"="0" {
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %size = call i32 @llvm.coro.size.i32()

llvm/test/Transforms/Coroutines/ex2.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -O2 -enable-coroutines -S | FileCheck %s
 ; RUN: opt < %s -passes='default<O2>' -enable-coroutines -S | FileCheck %s
 
-define i8* @f(i32 %n) {
+define i8* @f(i32 %n) "coroutine.presplit"="0" {
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %need.dyn.alloc = call i1 @llvm.coro.alloc(token %id)

llvm/test/Transforms/Coroutines/ex3.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -O2 -enable-coroutines -S | FileCheck %s
 ; RUN: opt < %s -aa-pipeline=basic-aa -passes='default<O2>' -enable-coroutines -S | FileCheck %s
 
-define i8* @f(i32 %n) {
+define i8* @f(i32 %n) "coroutine.presplit"="0" {
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %size = call i32 @llvm.coro.size.i32()

llvm/test/Transforms/Coroutines/ex4.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -O2 -enable-coroutines -S | FileCheck %s
 ; RUN: opt < %s -passes='default<O2>' -enable-coroutines -S | FileCheck %s
 
-define i8* @f(i32 %n) {
+define i8* @f(i32 %n) "coroutine.presplit"="0" {
 entry:
   %promise = alloca i32
   %pv = bitcast i32* %promise to i8*

llvm/test/Transforms/Coroutines/ex5.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -O2 -enable-coroutines -preserve-alignment-assumptions-during-inlining=false -S | FileCheck %s
 ; RUN: opt < %s -aa-pipeline=basic-aa -passes='default<O2>' -enable-coroutines -preserve-alignment-assumptions-during-inlining=false -S | FileCheck %s
 
-define i8* @f(i32 %n) {
+define i8* @f(i32 %n) "coroutine.presplit"="0" {
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %size = call i32 @llvm.coro.size.i32()

llvm/test/Transforms/Coroutines/phi-coro-end.ll

@@ -2,7 +2,7 @@
 ; RUN: opt < %s -O2 -enable-coroutines -S | FileCheck %s
 ; RUN: opt < %s -aa-pipeline=basic-aa -passes='default<O2>' -enable-coroutines -S | FileCheck %s
 
-define i8* @f(i32 %n) {
+define i8* @f(i32 %n) "coroutine.presplit"="0" {
 entry:
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %size = call i32 @llvm.coro.size.i32()

llvm/test/Transforms/Coroutines/restart-trigger.ll

@@ -12,7 +12,7 @@
 ; CHECK:      CoroSplit: Processing coroutine 'f' state: 0
 ; CHECK-NEXT: CoroSplit: Processing coroutine 'f' state: 1
 
-define void @f() {
+define void @f() "coroutine.presplit"="0" {
   %id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
   %size = call i32 @llvm.coro.size.i32()
   %alloc = call i8* @malloc(i32 %size)