clang/test/CodeGenCoroutines/coro-await.cpp

   1 // RUN: %clang_cc1 -no-opaque-pointers -no-enable-noundef-analysis -triple x86_64-unknown-linux-gnu -std=c++20 \
   2 // RUN:   -emit-llvm %s -o - -disable-llvm-passes -Wno-coroutine -Wno-unused | FileCheck %s
   3
   4 namespace std {
   5 template <typename... T>
   6 struct coroutine_traits;
   7
   8 template <typename Promise = void> struct coroutine_handle;
   9
  10 template <>
  11 struct coroutine_handle<void> {
  12   void *ptr;
  13   static coroutine_handle from_address(void *);
  14   void *address();
  15 };
  16
  17 template <typename Promise>
  18 struct coroutine_handle : coroutine_handle<> {
  19   static coroutine_handle from_address(void *) noexcept;
  20 };
  21
  22 } // namespace std
  23
  24 struct init_susp {
  25   bool await_ready();
  26   void await_suspend(std::coroutine_handle<>);
  27   void await_resume();
  28 };
  29 struct final_susp {
  30   bool await_ready() noexcept;
  31   void await_suspend(std::coroutine_handle<>) noexcept;
  32   void await_resume() noexcept;
  33 };
  34
  35 struct suspend_always {
  36   int stuff;
  37   bool await_ready();
  38   void await_suspend(std::coroutine_handle<>);
  39   void await_resume();
  40 };
  41
  42 template <>
  43 struct std::coroutine_traits<void> {
  44   struct promise_type {
  45     void get_return_object();
  46     init_susp initial_suspend();
  47     final_susp final_suspend() noexcept;
  48     void return_void();
  49   };
  50 };
  51
  52 // CHECK-LABEL: f0(
  53 extern "C" void f0() {
  54   // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
  55
  56   // See if initial_suspend was issued:
  57   // ----------------------------------
  58   // CHECK: call void @_ZNSt16coroutine_traitsIJvEE12promise_type15initial_suspendEv(
  59   // CHECK-NEXT: call zeroext i1 @_ZN9init_susp11await_readyEv(%struct.init_susp*
  60   // CHECK: %[[INITSP_ID:.+]] = call token @llvm.coro.save(
  61   // CHECK: call i8 @llvm.coro.suspend(token %[[INITSP_ID]], i1 false)
  62
  63   co_await suspend_always{};
  64   // See if we need to suspend:
  65   // --------------------------
  66   // CHECK: %[[READY:.+]] = call zeroext i1 @_ZN14suspend_always11await_readyEv(%struct.suspend_always* {{[^,]*}} %[[AWAITABLE:.+]])
  67   // CHECK: br i1 %[[READY]], label %[[READY_BB:.+]], label %[[SUSPEND_BB:.+]]
  68
  69   // If we are suspending:
  70   // ---------------------
  71   // CHECK: [[SUSPEND_BB]]:
  72   // CHECK: %[[SUSPEND_ID:.+]] = call token @llvm.coro.save(
  73   // ---------------------------
  74   // Build the coroutine handle and pass it to await_suspend
  75   // ---------------------------
  76   // CHECK: call i8* @_ZNSt16coroutine_handleINSt16coroutine_traitsIJvEE12promise_typeEE12from_addressEPv(i8* %[[FRAME]])
  77   //   ... many lines of code to coerce coroutine_handle into an i8* scalar
  78   // CHECK: %[[CH:.+]] = load i8*, i8** %{{.+}}
  79   // CHECK: call void @_ZN14suspend_always13await_suspendESt16coroutine_handleIvE(%struct.suspend_always* {{[^,]*}} %[[AWAITABLE]], i8* %[[CH]])
  80   // -------------------------
  81   // Generate a suspend point:
  82   // -------------------------
  83   // CHECK: %[[OUTCOME:.+]] = call i8 @llvm.coro.suspend(token %[[SUSPEND_ID]], i1 false)
  84   // CHECK: switch i8 %[[OUTCOME]], label %[[RET_BB:.+]] [
  85   // CHECK:   i8 0, label %[[READY_BB]]
  86   // CHECK:   i8 1, label %[[CLEANUP_BB:.+]]
  87   // CHECK: ]
  88
  89   // Cleanup code goes here:
  90   // -----------------------
  91   // CHECK: [[CLEANUP_BB]]:
  92
  93   // When coroutine is resumed, call await_resume
  94   // --------------------------
  95   // CHECK: [[READY_BB]]:
  96   // CHECK:  call void @_ZN14suspend_always12await_resumeEv(%struct.suspend_always* {{[^,]*}} %[[AWAITABLE]])
  97
  98   // See if final_suspend was issued:
  99   // ----------------------------------
 100   // CHECK: call void @_ZNSt16coroutine_traitsIJvEE12promise_type13final_suspendEv(
 101   // CHECK-NEXT: call zeroext i1 @_ZN10final_susp11await_readyEv(%struct.final_susp*
 102   // CHECK: %[[FINALSP_ID:.+]] = call token @llvm.coro.save(
 103   // CHECK: call i8 @llvm.coro.suspend(token %[[FINALSP_ID]], i1 true)
 104 }
 105
 106 struct suspend_maybe {
 107   float stuff;
 108   ~suspend_maybe();
 109   bool await_ready();
 110   bool await_suspend(std::coroutine_handle<>);
 111   void await_resume();
 112 };
 113
 114 template <>
 115 struct std::coroutine_traits<void, int> {
 116   struct promise_type {
 117     void get_return_object();
 118     init_susp initial_suspend();
 119     final_susp final_suspend() noexcept;
 120     void return_void();
 121     suspend_maybe yield_value(int);
 122   };
 123 };
 124
 125 // CHECK-LABEL: f1(
 126 extern "C" void f1(int) {
 127   // CHECK: %[[PROMISE:.+]] = alloca %"struct.std::coroutine_traits<void, int>::promise_type"
 128   // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
 129   co_yield 42;
 130   // CHECK: call void @_ZNSt16coroutine_traitsIJviEE12promise_type11yield_valueEi(%struct.suspend_maybe* sret(%struct.suspend_maybe) align 4 %[[AWAITER:.+]], %"struct.std::coroutine_traits<void, int>::promise_type"* {{[^,]*}} %[[PROMISE]], i32 42)
 131
 132   // See if we need to suspend:
 133   // --------------------------
 134   // CHECK: %[[READY:.+]] = call zeroext i1 @_ZN13suspend_maybe11await_readyEv(%struct.suspend_maybe* {{[^,]*}} %[[AWAITABLE]])
 135   // CHECK: br i1 %[[READY]], label %[[READY_BB:.+]], label %[[SUSPEND_BB:.+]]
 136
 137   // If we are suspending:
 138   // ---------------------
 139   // CHECK: [[SUSPEND_BB]]:
 140   // CHECK: %[[SUSPEND_ID:.+]] = call token @llvm.coro.save(
 141   // ---------------------------
 142   // Build the coroutine handle and pass it to await_suspend
 143   // ---------------------------
 144   // CHECK: call i8* @_ZNSt16coroutine_handleINSt16coroutine_traitsIJviEE12promise_typeEE12from_addressEPv(i8* %[[FRAME]])
 145   //   ... many lines of code to coerce coroutine_handle into an i8* scalar
 146   // CHECK: %[[CH:.+]] = load i8*, i8** %{{.+}}
 147   // CHECK: %[[YES:.+]] = call zeroext i1 @_ZN13suspend_maybe13await_suspendESt16coroutine_handleIvE(%struct.suspend_maybe* {{[^,]*}} %[[AWAITABLE]], i8* %[[CH]])
 148   // -------------------------------------------
 149   // See if await_suspend decided not to suspend
 150   // -------------------------------------------
 151   // CHECK: br i1 %[[YES]], label %[[SUSPEND_PLEASE:.+]], label %[[READY_BB]]
 152
 153   // CHECK: [[SUSPEND_PLEASE]]:
 154   // CHECK:    call i8 @llvm.coro.suspend(token %[[SUSPEND_ID]], i1 false)
 155
 156   // CHECK: [[READY_BB]]:
 157   // CHECK:     call void @_ZN13suspend_maybe12await_resumeEv(%struct.suspend_maybe* {{[^,]*}} %[[AWAITABLE]])
 158 }
 159
 160 struct ComplexAwaiter {
 161   template <typename F> void await_suspend(F);
 162   bool await_ready();
 163   _Complex float await_resume();
 164 };
 165 extern "C" void UseComplex(_Complex float);
 166
 167 // CHECK-LABEL: @TestComplex(
 168 extern "C" void TestComplex() {
 169   UseComplex(co_await ComplexAwaiter{});
 170   // CHECK: call <2 x float> @_ZN14ComplexAwaiter12await_resumeEv(%struct.ComplexAwaiter*
 171   // CHECK: call void @UseComplex(<2 x float> %{{.+}})
 172
 173   co_await ComplexAwaiter{};
 174   // CHECK: call <2 x float> @_ZN14ComplexAwaiter12await_resumeEv(%struct.ComplexAwaiter*
 175
 176   _Complex float Val = co_await ComplexAwaiter{};
 177   // CHECK: call <2 x float> @_ZN14ComplexAwaiter12await_resumeEv(%struct.ComplexAwaiter*
 178 }
 179
 180 struct Aggr { int X, Y, Z; ~Aggr(); };
 181 struct AggrAwaiter {
 182   template <typename F> void await_suspend(F);
 183   bool await_ready();
 184   Aggr await_resume();
 185 };
 186
 187 extern "C" void Whatever();
 188 extern "C" void UseAggr(Aggr&&);
 189
 190 // FIXME: Once the cleanup code is in, add testing that destructors for Aggr
 191 // are invoked properly on the cleanup branches.
 192
 193 // CHECK-LABEL: @TestAggr(
 194 extern "C" void TestAggr() {
 195   UseAggr(co_await AggrAwaiter{});
 196   Whatever();
 197   // CHECK: call void @_ZN11AggrAwaiter12await_resumeEv(%struct.Aggr* sret(%struct.Aggr) align 4 %[[AwaitResume:.+]],
 198   // CHECK: call void @UseAggr(%struct.Aggr* nonnull align 4 dereferenceable(12) %[[AwaitResume]])
 199   // CHECK: call void @_ZN4AggrD1Ev(%struct.Aggr* {{[^,]*}} %[[AwaitResume]])
 200   // CHECK: call void @Whatever()
 201
 202   co_await AggrAwaiter{};
 203   Whatever();
 204   // CHECK: call void @_ZN11AggrAwaiter12await_resumeEv(%struct.Aggr* sret(%struct.Aggr) align 4 %[[AwaitResume2:.+]],
 205   // CHECK: call void @_ZN4AggrD1Ev(%struct.Aggr* {{[^,]*}} %[[AwaitResume2]])
 206   // CHECK: call void @Whatever()
 207
 208   Aggr Val = co_await AggrAwaiter{};
 209   Whatever();
 210   // CHECK: call void @_ZN11AggrAwaiter12await_resumeEv(%struct.Aggr* sret(%struct.Aggr) align 4 %[[AwaitResume3:.+]],
 211   // CHECK: call void @Whatever()
 212   // CHECK: call void @_ZN4AggrD1Ev(%struct.Aggr* {{[^,]*}} %[[AwaitResume3]])
 213 }
 214
 215 struct ScalarAwaiter {
 216   template <typename F> void await_suspend(F);
 217   bool await_ready();
 218   int await_resume();
 219 };
 220
 221 extern "C" void UseScalar(int);
 222
 223 // CHECK-LABEL: @TestScalar(
 224 extern "C" void TestScalar() {
 225   UseScalar(co_await ScalarAwaiter{});
 226   // CHECK: %[[Result:.+]] = call i32 @_ZN13ScalarAwaiter12await_resumeEv(%struct.ScalarAwaiter*
 227   // CHECK: call void @UseScalar(i32 %[[Result]])
 228
 229   int Val = co_await ScalarAwaiter{};
 230   // CHECK: %[[Result2:.+]] = call i32 @_ZN13ScalarAwaiter12await_resumeEv(%struct.ScalarAwaiter*
 231   // CHECK: store i32 %[[Result2]], i32* %[[TMP_EXPRCLEANUP:.+]],
 232   // CHECK: %[[TMP:.+]] = load i32, i32* %[[TMP_EXPRCLEANUP]],
 233   // CHECK: store i32 %[[TMP]], i32* %Val,
 234
 235   co_await ScalarAwaiter{};
 236   // CHECK: call i32 @_ZN13ScalarAwaiter12await_resumeEv(%struct.ScalarAwaiter*
 237 }
 238
 239 // Test operator co_await codegen.
 240 enum class MyInt: int {};
 241 ScalarAwaiter operator co_await(MyInt);
 242
 243 struct MyAgg {
 244   AggrAwaiter operator co_await();
 245 };
 246
 247 // CHECK-LABEL: @TestOpAwait(
 248 extern "C" void TestOpAwait() {
 249   co_await MyInt(42);
 250   // CHECK: call void @_Zaw5MyInt(i32 42)
 251   // CHECK: call i32 @_ZN13ScalarAwaiter12await_resumeEv(%struct.ScalarAwaiter* {{[^,]*}} %
 252
 253   co_await MyAgg{};
 254   // CHECK: call void @_ZN5MyAggawEv(%struct.MyAgg* {{[^,]*}} %
 255   // CHECK: call void @_ZN11AggrAwaiter12await_resumeEv(%struct.Aggr* sret(%struct.Aggr) align 4 %
 256 }
 257
 258 // CHECK-LABEL: EndlessLoop(
 259 extern "C" void EndlessLoop() {
 260   // CHECK: %[[FRAME:.+]] = call i8* @llvm.coro.begin(
 261
 262   // See if initial_suspend was issued:
 263   // ----------------------------------
 264   // CHECK: call void @_ZNSt16coroutine_traitsIJvEE12promise_type15initial_suspendEv(
 265   // CHECK-NEXT: call zeroext i1 @_ZN9init_susp11await_readyEv(%struct.init_susp*
 266
 267   for (;;)
 268     co_await suspend_always{};
 269
 270   // Verify that final_suspend was NOT issued:
 271   // ----------------------------------
 272   // CHECK-NOT: call void @_ZNSt16coroutine_traitsIJvEE12promise_type13final_suspendEv(
 273   // CHECK-NOT: call zeroext i1 @_ZN10final_susp11await_readyEv(%struct.final_susp*
 274 }
 275
 276 // Verifies that we don't crash when awaiting on an lvalue.
 277 // CHECK-LABEL: @_Z11AwaitLValuev(
 278 void AwaitLValue() {
 279   suspend_always lval;
 280   co_await lval;
 281 }
 282
 283 struct RefTag { };
 284
 285 struct AwaitResumeReturnsLValue {
 286   bool await_ready();
 287   void await_suspend(std::coroutine_handle<>);
 288   RefTag& await_resume();
 289 };
 290
 291 template <>
 292 struct std::coroutine_traits<void, double> {
 293   struct promise_type {
 294     void get_return_object();
 295     init_susp initial_suspend();
 296     final_susp final_suspend() noexcept;
 297     void return_void();
 298     AwaitResumeReturnsLValue yield_value(int);
 299   };
 300 };
 301
 302 // Verifies that we don't crash when returning an lvalue from an await_resume()
 303 // expression.
 304 // CHECK-LABEL:  define{{.*}} void @_Z18AwaitReturnsLValued(double %0)
 305 void AwaitReturnsLValue(double) {
 306   AwaitResumeReturnsLValue a;
 307   // CHECK: %[[AVAR:.+]] = alloca %struct.AwaitResumeReturnsLValue,
 308   // CHECK: %[[XVAR:.+]] = alloca %struct.RefTag*,
 309
 310   // CHECK: %[[YVAR:.+]] = alloca %struct.RefTag*,
 311   // CHECK-NEXT: %[[TMP1:.+]] = alloca %struct.AwaitResumeReturnsLValue,
 312
 313   // CHECK: %[[TMP_EXPRCLEANUP1:.+]] = alloca %struct.RefTag*,
 314   // CHECK: %[[ZVAR:.+]] = alloca %struct.RefTag*,
 315   // CHECK-NEXT: %[[TMP2:.+]] = alloca %struct.AwaitResumeReturnsLValue,
 316   // CHECK: %[[TMP_EXPRCLEANUP2:.+]] = alloca %struct.RefTag*,
 317
 318   // CHECK: %[[RES1:.+]] = call nonnull align 1 dereferenceable({{.*}}) %struct.RefTag* @_ZN24AwaitResumeReturnsLValue12await_resumeEv(%struct.AwaitResumeReturnsLValue* {{[^,]*}} %[[AVAR]])
 319   // CHECK-NEXT: store %struct.RefTag* %[[RES1]], %struct.RefTag** %[[XVAR]],
 320   RefTag& x = co_await a;
 321
 322   // CHECK: %[[RES2:.+]] = call nonnull align 1 dereferenceable({{.*}}) %struct.RefTag* @_ZN24AwaitResumeReturnsLValue12await_resumeEv(%struct.AwaitResumeReturnsLValue* {{[^,]*}} %[[TMP1]])
 323   // CHECK-NEXT: store %struct.RefTag* %[[RES2]], %struct.RefTag** %[[TMP_EXPRCLEANUP1]],
 324   // CHECK: %[[LOAD_TMP1:.+]] = load %struct.RefTag*, %struct.RefTag** %[[TMP_EXPRCLEANUP1]],
 325   // CHECK: store %struct.RefTag* %[[LOAD_TMP1]], %struct.RefTag** %[[YVAR]],
 326
 327   RefTag& y = co_await AwaitResumeReturnsLValue{};
 328   // CHECK: %[[RES3:.+]] = call nonnull align 1 dereferenceable({{.*}}) %struct.RefTag* @_ZN24AwaitResumeReturnsLValue12await_resumeEv(%struct.AwaitResumeReturnsLValue* {{[^,]*}} %[[TMP2]])
 329   // CHECK-NEXT: store %struct.RefTag* %[[RES3]], %struct.RefTag** %[[TMP_EXPRCLEANUP2]],
 330   // CHECK: %[[LOAD_TMP2:.+]] = load %struct.RefTag*, %struct.RefTag** %[[TMP_EXPRCLEANUP2]],
 331   // CHECK: store %struct.RefTag* %[[LOAD_TMP2]], %struct.RefTag** %[[ZVAR]],
 332   RefTag& z = co_yield 42;
 333 }
 334
 335 struct TailCallAwait {
 336   bool await_ready();
 337   std::coroutine_handle<> await_suspend(std::coroutine_handle<>);
 338   void await_resume();
 339 };
 340
 341 // CHECK-LABEL: @TestTailcall(
 342 extern "C" void TestTailcall() {
 343   co_await TailCallAwait{};
 344
 345   // CHECK: %[[RESULT:.+]] = call i8* @_ZN13TailCallAwait13await_suspendESt16coroutine_handleIvE(%struct.TailCallAwait*
 346   // CHECK: %[[COERCE:.+]] = getelementptr inbounds %"struct.std::coroutine_handle", %"struct.std::coroutine_handle"* %[[TMP:.+]], i32 0, i32 0
 347   // CHECK: store i8* %[[RESULT]], i8** %[[COERCE]]
 348   // CHECK: %[[ADDR:.+]] = call i8* @_ZNSt16coroutine_handleIvE7addressEv(%"struct.std::coroutine_handle"* {{[^,]*}} %[[TMP]])
 349   // CHECK: call void @llvm.coro.resume(i8* %[[ADDR]])
 350 }