51d5d7bbae
One of the main user of these kind of coroutines is swift. There yield-once (`retcon.once`) coroutines are used to temporary "expose" pointers to internal fields of various objects creating borrow scopes. However, in some cases it might be useful also to allow these coroutines to produce a normal result, but there is no convenient way to represent this (as compared to switched-resume kind of coroutines where C++ `co_return` is transformed to a member / callback call on promise object). The extension is simple: we allow continuation function to have a non-void result and accept optional extra arguments via a special `llvm.coro.end.result` intrinsic that would essentially forward them as normal results.
55 lines
1.7 KiB
LLVM
55 lines
1.7 KiB
LLVM
; First example from Doc/Coroutines.rst (one block loop)
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; RUN: opt < %s -aa-pipeline=basic-aa -passes='default<O2>' -preserve-alignment-assumptions-during-inlining=false -S | FileCheck %s
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define ptr @f(i32 %n) presplitcoroutine {
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entry:
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%id = call token @llvm.coro.id(i32 0, ptr null, ptr null, ptr null)
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%size = call i32 @llvm.coro.size.i32()
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%alloc = call ptr @malloc(i32 %size)
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%hdl = call noalias ptr @llvm.coro.begin(token %id, ptr %alloc)
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br label %loop
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loop:
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%n.val = phi i32 [ %n, %entry ], [ %inc, %loop ]
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%inc = add nsw i32 %n.val, 1
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call void @print(i32 %n.val)
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%0 = call i8 @llvm.coro.suspend(token none, i1 false)
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switch i8 %0, label %suspend [i8 0, label %loop
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i8 1, label %cleanup]
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cleanup:
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%mem = call ptr @llvm.coro.free(token %id, ptr %hdl)
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call void @free(ptr %mem)
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br label %suspend
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suspend:
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call i1 @llvm.coro.end(ptr %hdl, i1 false, token none)
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ret ptr %hdl
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}
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; CHECK-LABEL: @main(
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define i32 @main() {
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entry:
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%hdl = call ptr @f(i32 4)
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call void @llvm.coro.resume(ptr %hdl)
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call void @llvm.coro.resume(ptr %hdl)
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call void @llvm.coro.destroy(ptr %hdl)
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ret i32 0
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; CHECK-NEXT: entry:
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; CHECK: call void @print(i32 4)
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; CHECK: call void @print(i32 5)
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; CHECK: call void @print(i32 6)
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; CHECK: ret i32 0
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}
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declare ptr @malloc(i32)
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declare void @free(ptr)
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declare void @print(i32)
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declare token @llvm.coro.id(i32, ptr, ptr, ptr)
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declare i32 @llvm.coro.size.i32()
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declare ptr @llvm.coro.begin(token, ptr)
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declare i8 @llvm.coro.suspend(token, i1)
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declare ptr @llvm.coro.free(token, ptr)
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declare i1 @llvm.coro.end(ptr, i1, token)
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declare void @llvm.coro.resume(ptr)
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declare void @llvm.coro.destroy(ptr)
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