[Coro] [async] Disable inlining in async coroutine splitting for swifttailcc thunks #87549

aschwaighofer · 2024-04-03T20:02:04Z

The call to the inlining utility does not update the call graph. Leading to assertion failures when calling the call graph utility to update the call graph.

Instead rely on an inline pass to run after coro splitting and use alwaysinline annotations.

We can only do this if the calling convention used for the thunks is swifttailcc otherwise we would break clients that use other calling conventions.

Previous instance of this PR was #80904.

github.com/swiftlang/swift/issues/68708

llvmbot · 2024-04-03T20:02:41Z

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-coroutines

Author: Arnold Schwaighofer (aschwaighofer)

Changes

The call to the inlining utility does not update the call graph. Leading to assertion failures when calling the call graph utility to update the call graph.

Instead rely on an inline pass to run after coro splitting and use alwaysinline annotations.

We can only do this if the calling convention used for the thunks is swifttailcc otherwise we would break clients that use other calling conventions.

Previous instance of this PR was #80904.

github.com/swiftlang/swift/issues/68708

Full diff: https://github.com/llvm/llvm-project/pull/87549.diff

3 Files Affected:

(modified) llvm/lib/Transforms/Coroutines/CoroSplit.cpp (+11-6)
(added) llvm/test/Transforms/Coroutines/coro-async-mutually-recursive.ll (+158)
(modified) llvm/test/Transforms/Coroutines/swift-async-dbg.ll (+15-15)

diff --git a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
index 3a43b1edcaba37..c965945d88b79a 100644
--- a/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
+++ b/llvm/lib/Transforms/Coroutines/CoroSplit.cpp
@@ -256,16 +256,18 @@ static bool replaceCoroEndAsync(AnyCoroEndInst *End) {
   // Insert the return instruction.
   Builder.SetInsertPoint(End);
   Builder.CreateRetVoid();
-  InlineFunctionInfo FnInfo;
 
   // Remove the rest of the block, by splitting it into an unreachable block.
   auto *BB = End->getParent();
   BB->splitBasicBlock(End);
   BB->getTerminator()->eraseFromParent();
 
-  auto InlineRes = InlineFunction(*MustTailCall, FnInfo);
-  assert(InlineRes.isSuccess() && "Expected inlining to succeed");
-  (void)InlineRes;
+  if (MustTailCallFunc->getCallingConv() != CallingConv::SwiftTail) {
+    InlineFunctionInfo FnInfo;
+    auto InlineRes = InlineFunction(*MustTailCall, FnInfo);
+    assert(InlineRes.isSuccess() && "Expected inlining to succeed");
+    (void)InlineRes;
+  }
 
   // We have cleaned up the coro.end block above.
   return false;
@@ -1882,8 +1884,11 @@ static void splitAsyncCoroutine(Function &F, coro::Shape &Shape,
     auto *TailCall = coro::createMustTailCall(Suspend->getDebugLoc(), Fn, TTI,
                                               FnArgs, Builder);
     Builder.CreateRetVoid();
-    InlineFunctionInfo FnInfo;
-    (void)InlineFunction(*TailCall, FnInfo);
+
+    if (Fn->getCallingConv() != CallingConv::SwiftTail) {
+      InlineFunctionInfo FnInfo;
+      (void)InlineFunction(*TailCall, FnInfo);
+    }
 
     // Replace the lvm.coro.async.resume intrisic call.
     replaceAsyncResumeFunction(Suspend, Continuation);
diff --git a/llvm/test/Transforms/Coroutines/coro-async-mutually-recursive.ll b/llvm/test/Transforms/Coroutines/coro-async-mutually-recursive.ll
new file mode 100644
index 00000000000000..4931fe998daa60
--- /dev/null
+++ b/llvm/test/Transforms/Coroutines/coro-async-mutually-recursive.ll
@@ -0,0 +1,158 @@
+; RUN: opt < %s -passes='default<O2>' -S | FileCheck --check-prefixes=CHECK %s
+; RUN: opt < %s -O0 -S | FileCheck --check-prefixes=CHECK-O0 %s
+
+
+; CHECK-NOT: llvm.coro.suspend.async
+; CHECK-O0-NOT: llvm.coro.suspend.async
+
+; This test used to crash during updating the call graph in coro splitting.
+
+target datalayout = "p:64:64:64"
+
+%swift.async_func_pointer = type <{ i32, i32 }>
+
+@"$s1d3fooyySbYaFTu" = hidden global %swift.async_func_pointer <{ i32 trunc (i64 sub (i64 ptrtoint (ptr @"$s1d3fooyySbYaF" to i64), i64 ptrtoint (ptr @"$s1d3fooyySbYaFTu" to i64)) to i32), i32 16 }>
+@"$s1d3baryySbYaFTu" = hidden global %swift.async_func_pointer <{ i32 trunc (i64 sub (i64 ptrtoint (ptr @"$s1d3baryySbYaF" to i64), i64 ptrtoint (ptr @"$s1d3baryySbYaFTu" to i64)) to i32), i32 16 }>
+
+define swifttailcc void @"$s1d3fooyySbYaF"(ptr swiftasync %0, i1 %1) {
+entry:
+  %2 = alloca ptr, align 8
+  %c.debug = alloca i1, align 8
+  %3 = call token @llvm.coro.id.async(i32 16, i32 16, i32 0, ptr @"$s1d3fooyySbYaFTu")
+  %4 = call ptr @llvm.coro.begin(token %3, ptr null)
+  store ptr %0, ptr %2, align 8
+  call void @llvm.memset.p0.i64(ptr align 8 %c.debug, i8 0, i64 1, i1 false)
+  store i1 %1, ptr %c.debug, align 8
+  call void asm sideeffect "", "r"(ptr %c.debug)
+  %5 = load i32, ptr getelementptr inbounds (%swift.async_func_pointer, ptr @"$s1d3baryySbYaFTu", i32 0, i32 1), align 8
+  %6 = zext i32 %5 to i64
+  %7 = call swiftcc ptr @swift_task_alloc(i64 %6) #4
+  call void @llvm.lifetime.start.p0(i64 -1, ptr %7)
+  %8 = load ptr, ptr %2, align 8
+  %9 = getelementptr inbounds <{ ptr, ptr }>, ptr %7, i32 0, i32 0
+  store ptr %8, ptr %9, align 8
+  %10 = call ptr @llvm.coro.async.resume()
+  %11 = getelementptr inbounds <{ ptr, ptr }>, ptr %7, i32 0, i32 1
+  store ptr %10, ptr %11, align 8
+  %12 = call { ptr } (i32, ptr, ptr, ...) @llvm.coro.suspend.async.sl_p0s(i32 0, ptr %10, ptr @__swift_async_resume_project_context, ptr @"$s1d3fooyySbYaF.0", ptr @"$s1d3baryySbYaF", ptr %7, i1 %1)
+  %13 = extractvalue { ptr } %12, 0
+  %14 = call ptr @__swift_async_resume_project_context(ptr %13)
+  store ptr %14, ptr %2, align 8
+  call swiftcc void @swift_task_dealloc(ptr %7) #4
+  call void @llvm.lifetime.end.p0(i64 -1, ptr %7)
+  %15 = load ptr, ptr %2, align 8
+  %16 = getelementptr inbounds <{ ptr, ptr }>, ptr %15, i32 0, i32 1
+  %17 = load ptr, ptr %16, align 8
+  %18 = load ptr, ptr %2, align 8
+  %19 = call i1 (ptr, i1, ...) @llvm.coro.end.async(ptr %4, i1 false, ptr @"$s1d3fooyySbYaF.0.1", ptr %17, ptr %18)
+  unreachable
+}
+
+declare token @llvm.coro.id.async(i32, i32, i32, ptr) #1
+
+declare void @llvm.trap() #2
+
+declare ptr @llvm.coro.begin(token, ptr) #1
+
+declare void @llvm.memset.p0.i64(ptr nocapture, i8, i64, i1 immarg) #3
+
+define hidden swifttailcc void @"$s1d3baryySbYaF"(ptr swiftasync %0, i1 %1) {
+entry:
+  %2 = alloca ptr, align 8
+  %c.debug = alloca i1, align 8
+  %3 = call token @llvm.coro.id.async(i32 16, i32 16, i32 0, ptr @"$s1d3baryySbYaFTu")
+  %4 = call ptr @llvm.coro.begin(token %3, ptr null)
+  store ptr %0, ptr %2, align 8
+  call void @llvm.memset.p0.i64(ptr align 8 %c.debug, i8 0, i64 1, i1 false)
+  store i1 %1, ptr %c.debug, align 8
+  call void asm sideeffect "", "r"(ptr %c.debug)
+  br i1 %1, label %5, label %17
+
+5:                                                ; preds = %entry
+  %6 = xor i1 %1, true
+  %7 = load i32, ptr getelementptr inbounds (%swift.async_func_pointer, ptr @"$s1d3fooyySbYaFTu", i32 0, i32 1), align 8
+  %8 = zext i32 %7 to i64
+  %9 = call swiftcc ptr @swift_task_alloc(i64 %8) #4
+  call void @llvm.lifetime.start.p0(i64 -1, ptr %9)
+  %10 = load ptr, ptr %2, align 8
+  %11 = getelementptr inbounds <{ ptr, ptr }>, ptr %9, i32 0, i32 0
+  store ptr %10, ptr %11, align 8
+  %12 = call ptr @llvm.coro.async.resume()
+  %13 = getelementptr inbounds <{ ptr, ptr }>, ptr %9, i32 0, i32 1
+  store ptr %12, ptr %13, align 8
+  %14 = call { ptr } (i32, ptr, ptr, ...) @llvm.coro.suspend.async.sl_p0s(i32 0, ptr %12, ptr @__swift_async_resume_project_context, ptr @"$s1d3baryySbYaF.0.2", ptr @"$s1d3fooyySbYaF", ptr %9, i1 %6)
+  %15 = extractvalue { ptr } %14, 0
+  %16 = call ptr @__swift_async_resume_project_context(ptr %15)
+  store ptr %16, ptr %2, align 8
+  call swiftcc void @swift_task_dealloc(ptr %9) #4
+  call void @llvm.lifetime.end.p0(i64 -1, ptr %9)
+  br label %18
+
+17:                                               ; preds = %entry
+  br label %18
+
+18:                                               ; preds = %5, %17
+  %19 = load ptr, ptr %2, align 8
+  %20 = getelementptr inbounds <{ ptr, ptr }>, ptr %19, i32 0, i32 1
+  %21 = load ptr, ptr %20, align 8
+  %22 = load ptr, ptr %2, align 8
+  %23 = call i1 (ptr, i1, ...) @llvm.coro.end.async(ptr %4, i1 false, ptr @"$s1d3baryySbYaF.0", ptr %21, ptr %22)
+  unreachable
+}
+
+declare swiftcc ptr @swift_task_alloc(i64) #4
+
+declare void @llvm.lifetime.start.p0(i64 immarg, ptr nocapture) #5
+
+declare ptr @llvm.coro.async.resume() #6
+
+define linkonce_odr hidden ptr @__swift_async_resume_project_context(ptr %0) #7 {
+entry:
+  %1 = load ptr, ptr %0, align 8
+  %2 = call ptr @llvm.swift.async.context.addr()
+  store ptr %1, ptr %2, align 8
+  ret ptr %1
+}
+
+declare ptr @llvm.swift.async.context.addr() #1
+
+define internal swifttailcc void @"$s1d3fooyySbYaF.0"(ptr %0, ptr %1, i1 %2) #8 {
+entry:
+  musttail call swifttailcc void %0(ptr swiftasync %1, i1 %2)
+  ret void
+}
+
+declare { ptr } @llvm.coro.suspend.async.sl_p0s(i32, ptr, ptr, ...) #6
+
+declare swiftcc void @swift_task_dealloc(ptr) #4
+
+declare void @llvm.lifetime.end.p0(i64 immarg, ptr nocapture) #5
+
+define internal swifttailcc void @"$s1d3fooyySbYaF.0.1"(ptr %0, ptr %1) #8 {
+entry:
+  musttail call swifttailcc void %0(ptr swiftasync %1)
+  ret void
+}
+
+declare i1 @llvm.coro.end.async(ptr, i1, ...) #1
+
+define internal swifttailcc void @"$s1d3baryySbYaF.0"(ptr %0, ptr %1) #8 {
+entry:
+  musttail call swifttailcc void %0(ptr swiftasync %1)
+  ret void
+}
+
+define internal swifttailcc void @"$s1d3baryySbYaF.0.2"(ptr %0, ptr %1, i1 %2) #8 {
+entry:
+  musttail call swifttailcc void %0(ptr swiftasync %1, i1 %2)
+  ret void
+}
+
+attributes #1 = { nounwind }
+attributes #2 = { cold noreturn nounwind }
+attributes #3 = { nocallback nofree nounwind willreturn}
+attributes #4 = { nounwind }
+attributes #5 = { nocallback nofree nosync nounwind willreturn }
+attributes #6 = { nomerge nounwind }
+attributes #7 = { alwaysinline nounwind }
+attributes #8 = { alwaysinline nounwind }
diff --git a/llvm/test/Transforms/Coroutines/swift-async-dbg.ll b/llvm/test/Transforms/Coroutines/swift-async-dbg.ll
index 74edf7a3f3a540..a78bcdf0ddee23 100644
--- a/llvm/test/Transforms/Coroutines/swift-async-dbg.ll
+++ b/llvm/test/Transforms/Coroutines/swift-async-dbg.ll
@@ -1,13 +1,13 @@
-; RUN: opt -mtriple='arm64-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s
-; RUN: opt -mtriple='x86_64' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s
-; RUN: opt -mtriple='i386-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s --check-prefix=NOENTRY
-; RUN: opt -mtriple='armv7-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s --check-prefix=NOENTRY
+; RUN: opt -mtriple='arm64-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s
+; RUN: opt -mtriple='x86_64' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s
+; RUN: opt -mtriple='i386-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s --check-prefix=NOENTRY
+; RUN: opt -mtriple='armv7-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s --check-prefix=NOENTRY
 
 ;; Replicate those tests with non-instruction debug markers.
-; RUN: opt --try-experimental-debuginfo-iterators -mtriple='arm64-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s
-; RUN: opt --try-experimental-debuginfo-iterators -mtriple='x86_64' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s
-; RUN: opt --try-experimental-debuginfo-iterators -mtriple='i386-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s --check-prefix=NOENTRY
-; RUN: opt --try-experimental-debuginfo-iterators -mtriple='armv7-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg)' -o - | FileCheck %s --check-prefix=NOENTRY
+; RUN: opt --try-experimental-debuginfo-iterators -mtriple='arm64-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s
+; RUN: opt --try-experimental-debuginfo-iterators -mtriple='x86_64' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s
+; RUN: opt --try-experimental-debuginfo-iterators -mtriple='i386-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s --check-prefix=NOENTRY
+; RUN: opt --try-experimental-debuginfo-iterators -mtriple='armv7-' %s -S -passes='module(coro-early),cgscc(coro-split,simplifycfg),always-inline' -o - | FileCheck %s --check-prefix=NOENTRY
 
 ; NOENTRY-NOT: OP_llvm_entry_value
 
@@ -93,29 +93,29 @@ define swifttailcc void @coroutineA(ptr swiftasync %arg) !dbg !48 {
 @coroutineBTu = global <{i32, i32}> <{ i32 trunc (i64 sub (i64 ptrtoint (ptr @"coroutineB" to i64), i64 ptrtoint (ptr @"coroutineBTu" to i64)) to i32), i32 16 }>, align 8
 @coroutineATu = global <{i32, i32}> <{ i32 trunc (i64 sub (i64 ptrtoint (ptr @"coroutineA" to i64), i64 ptrtoint (ptr @"coroutineATu" to i64)) to i32), i32 16 }>, align 8
 
-define weak_odr hidden ptr @__swift_async_resume_get_context(ptr %arg) !dbg !64 {
+define weak_odr hidden ptr @__swift_async_resume_get_context(ptr %arg) alwaysinline !dbg !64 {
   ret ptr %arg, !dbg !65
 }
-define hidden swifttailcc void @coroutineA.1(ptr %arg, i64 %arg1, i64 %arg2, ptr %arg3) !dbg !66 {
+define hidden swifttailcc void @coroutineA.1(ptr %arg, i64 %arg1, i64 %arg2, ptr %arg3) alwaysinline !dbg !66 {
   musttail call swifttailcc void @swift_task_switch(ptr swiftasync %arg3, ptr %arg, i64 %arg1, i64 %arg2), !dbg !67
   ret void, !dbg !67
 }
 
-define weak_odr hidden ptr @__swift_async_resume_project_context(ptr %arg) !dbg !68 {
+define weak_odr hidden ptr @__swift_async_resume_project_context(ptr %arg) alwaysinline !dbg !68 {
   %i1 = load ptr, ptr %arg, align 8, !dbg !69
   %i2 = call ptr @llvm.swift.async.context.addr(), !dbg !69
   store ptr %i1, ptr %i2, align 8, !dbg !69
   ret ptr %i1, !dbg !69
 }
-define hidden swifttailcc void @coroutineA.0(ptr %arg, ptr %arg1) !dbg !70 {
+define hidden swifttailcc void @coroutineA.0(ptr %arg, ptr %arg1) alwaysinline !dbg !70 {
   musttail call swifttailcc void %arg(ptr swiftasync %arg1), !dbg !71
   ret void, !dbg !71
 }
-define hidden swifttailcc void @coroutineA.0.1(ptr %arg, ptr %arg1) !dbg !72 {
+define hidden swifttailcc void @coroutineA.0.1(ptr %arg, ptr %arg1) alwaysinline !dbg !72 {
   musttail call swifttailcc void %arg(ptr swiftasync %arg1), !dbg !73
   ret void, !dbg !73
 }
-define swifttailcc void @coroutineB(ptr swiftasync %arg) !dbg !37 {
+define swifttailcc void @coroutineB(ptr swiftasync %arg) alwaysinline !dbg !37 {
   %i2 = call token @llvm.coro.id.async(i32 16, i32 16, i32 0, ptr nonnull @coroutineBTu)
   %i3 = call ptr @llvm.coro.begin(token %i2, ptr null)
   %i6 = getelementptr inbounds <{ ptr, ptr }>, ptr %arg, i64 0, i32 1, !dbg !42
@@ -123,7 +123,7 @@ define swifttailcc void @coroutineB(ptr swiftasync %arg) !dbg !37 {
   %i10 = call i1 (ptr, i1, ...) @llvm.coro.end.async(ptr %i3, i1 false, ptr nonnull @coroutineB.0, ptr %i712, ptr %arg), !dbg !42
   unreachable, !dbg !42
 }
-define hidden swifttailcc void @coroutineB.0(ptr %arg, ptr %arg1) !dbg !44 {
+define hidden swifttailcc void @coroutineB.0(ptr %arg, ptr %arg1) alwaysinline !dbg !44 {
   musttail call swifttailcc void %arg(ptr swiftasync %arg1), !dbg !47
   ret void, !dbg !47
 }

Mogball

Thanks! Do you mind adding the test case I had included in the revert commit?

Also, I am concerned that this basically only fixes the bug for Swift. Would other clients of the async coroutines still experience the out-of-date callgraph?

…ttailcc thunks The call to the inlining utility does not update the call graph. Leading to assertion failures when calling the call graph utility to update the call graph. Instead rely on an inline pass to run after coro splitting and use alwaysinline annotations. We can only do this if the calling convention used for the thunks is `swifttailcc` otherwise we would break clients that use other calling conventions. Previous instance of this PR was llvm#80904. github.com/swiftlang/swift/issues/68708

aschwaighofer · 2024-04-16T14:29:53Z

@Mogball it only fixes it if ‘swifttailcc’ is used.

Mogball

Fine with me and I'll keep that in mind, but it's unfortunate that the fix is forked based on the client of the coroutines....

aschwaighofer requested a review from Mogball April 3, 2024 20:02

llvmbot added coroutines C++20 coroutines llvm:transforms labels Apr 3, 2024

aschwaighofer force-pushed the corosplit_noinline_llvm.org_2nd branch from 279585a to 84003e2 Compare April 9, 2024 18:37

Mogball reviewed Apr 15, 2024

View reviewed changes

aschwaighofer force-pushed the corosplit_noinline_llvm.org_2nd branch from 84003e2 to 500b937 Compare April 16, 2024 12:38

Mogball reviewed Apr 16, 2024

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[Coro] [async] Disable inlining in async coroutine splitting for swifttailcc thunks #87549

[Coro] [async] Disable inlining in async coroutine splitting for swifttailcc thunks #87549

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edited

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