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.
60 lines
1.7 KiB
LLVM
60 lines
1.7 KiB
LLVM
; First example from Doc/Coroutines.rst (two 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 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, %resume ]
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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 %resume
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i8 1, label %cleanup]
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resume:
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%inc = add i32 %n.val, 1
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br label %loop
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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 0, 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: 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 token @llvm.coro.id(i32, ptr, ptr, ptr)
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declare ptr @llvm.coro.alloc(token)
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declare ptr @llvm.coro.free(token, ptr)
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declare i32 @llvm.coro.size.i32()
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declare i8 @llvm.coro.suspend(token, i1)
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declare void @llvm.coro.resume(ptr)
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declare void @llvm.coro.destroy(ptr)
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declare ptr @llvm.coro.begin(token, ptr)
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declare i1 @llvm.coro.end(ptr, i1, token)
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declare noalias ptr @malloc(i32)
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declare void @print(i32)
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declare void @free(ptr)
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