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[5.5] Cherry-pick a change from main to handle missing mandatory tail call optimizations #40451

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Merged
merged 2 commits into from
Dec 7, 2021
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[5.5] Cherry-pick a change from main to handle missing mandatory tail call optimizations #40451

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8079b35
[IRGen] Put 'ret void' instead of unreachable for non swiftasync cc
kateinoigakukun Oct 11, 2021
9fbf41c
test: repair the IRGen tests after #39680
compnerd Dec 7, 2021
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10 changes: 9 additions & 1 deletion lib/IRGen/GenCall.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -4949,7 +4949,15 @@ void irgen::emitAsyncReturn(
arguments.push_back(arg);

Builder.CreateIntrinsicCall(llvm::Intrinsic::coro_end_async, arguments);
Builder.CreateUnreachable();

if (IGF.IGM.AsyncTailCallKind == llvm::CallInst::TCK_MustTail) {
Builder.CreateUnreachable();
} else {
// If target doesn't support musttail (e.g. WebAssembly), the function
// passed to coro.end.async can return control back to the caller.
// So use ret void instead of unreachable to allow it.
Builder.CreateRetVoid();
}
}

void irgen::emitAsyncReturn(IRGenFunction &IGF, AsyncContextLayout &asyncLayout,
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13 changes: 9 additions & 4 deletions test/IRGen/async/hop_to_executor.sil
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@@ -1,7 +1,11 @@
// 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 | %IRGenFileCheck %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 | %IRGenFileCheck %s -check-prefix CHECK-%target-abi

// REQUIRES: concurrency

// WASI does not support the mandatory tail call, and needs to take the same
// path as CHECK-WIN, but will currently go down CHECK-SYSV, failing the test.
// XFAIL: OS=wasi

sil_stage canonical

import Builtin
Expand All @@ -10,13 +14,14 @@ import _Concurrency

// CHECK-LABEL: define{{.*}} void @test_simple(
// CHECK-SAME: %swift.context* swiftasync %0, [[INT]] %1, [[INT]] %2)
// CHECK: [[CTX:%[0-9]+]] = bitcast %swift.context* %0
// CHECK: [[RESUME:%[0-9]+]] = call i8* @llvm.coro.async.resume()
// CHECK-DAG: [[CTX:%[0-9]+]] = bitcast %swift.context* %0
// CHECK-DAG: [[RESUME:%[0-9]+]] = call i8* @llvm.coro.async.resume()
// CHECK-x86_64: call {{.*}} @llvm.coro.suspend.async{{.*}}(i32 0, i8* [[RESUME]], i8* bitcast (i8* (i8*)* @__swift_async_resume_get_context to i8*), i8* bitcast (void (i8*, [[INT]], [[INT]], %swift.context*)* @__swift_suspend_point to i8*), i8* [[RESUME]], [[INT]] %1, [[INT]] %2, %swift.context* {{%[0-9]+}})
// CHECK-arm64e: call {{.*}} @llvm.coro.suspend.async{{.*}}(i32 0, i8* [[RESUME]], i8* bitcast (i8* (i8*)* @__swift_async_resume_get_context to i8*), i8* bitcast (void (i8*, [[INT]], [[INT]], %swift.context*)* @__swift_suspend_point to i8*), i8* [[RESUME]], [[INT]] %1, [[INT]] %2, %swift.context* {{%[0-9]+}})
// CHECK: [[RET_CONTINUATION:%.*]] = bitcast void (%swift.context*)* {{.*}} to i8*
// CHECK: call i1 (i8*, i1, ...) @llvm.coro.end.async(i8* {{.*}}, i1 false, void (i8*, %swift.context*)* @[[TAIL_CALL_FUNC:.*]], i8* [[RET_CONTINUATION]]
// CHECK: unreachable
// CHECK-WIN: ret void
// CHECK-SYSV: unreachable

sil @test_simple : $@async (@guaranteed Optional<Builtin.Executor>) -> () {
bb0(%0 : $Optional<Builtin.Executor>):
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18 changes: 18 additions & 0 deletions test/IRGen/async/non_musttail_target.sil
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@@ -0,0 +1,18 @@
// Ensure that IRGen don't emit unreachable after coro.end.async for targets that don't support musttail call.
// RUN: %target-swift-frontend -disable-legacy-type-info -parse-stdlib %s -disable-llvm-optzns -disable-swift-specific-llvm-optzns -disable-objc-interop -module-name main -emit-ir -o - | %FileCheck %s

// REQUIRES: concurrency
// REQUIRES: OS=wasi || OS=windows-msvc

sil_stage canonical

import Builtin

sil @test_simple : $@async () -> () {
bb0:
%0 = tuple ()
return %0 : $()
// CHECK: call i1 (i8*, i1, ...) @llvm.coro.end.async
// CHECK-NOT: unreachable
// CHECK: ret void
}