llvm-project/llvm/test/Transforms/Coroutines/restart-trigger.ll

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[Coroutines] Part 6: Elide dynamic allocation of a coroutine frame when possible Summary: A particular coroutine usage pattern, where a coroutine is created, manipulated and destroyed by the same calling function, is common for coroutines implementing RAII idiom and is suitable for allocation elision optimization which avoid dynamic allocation by storing the coroutine frame as a static `alloca` in its caller. coro.free and coro.alloc intrinsics are used to indicate which code needs to be suppressed when dynamic allocation elision happens: ``` entry: %elide = call i8* @llvm.coro.alloc() %need.dyn.alloc = icmp ne i8* %elide, null br i1 %need.dyn.alloc, label %coro.begin, label %dyn.alloc dyn.alloc: %alloc = call i8* @CustomAlloc(i32 4) br label %coro.begin coro.begin: %phi = phi i8* [ %elide, %entry ], [ %alloc, %dyn.alloc ] %hdl = call i8* @llvm.coro.begin(i8* %phi, i32 0, i8* null, i8* bitcast ([2 x void (%f.frame*)*]* @f.resumers to i8*)) ``` and ``` %mem = call i8* @llvm.coro.free(i8* %hdl) %need.dyn.free = icmp ne i8* %mem, null br i1 %need.dyn.free, label %dyn.free, label %if.end dyn.free: call void @CustomFree(i8* %mem) br label %if.end if.end: ... ``` If heap allocation elision is performed, we replace coro.alloc with a static alloca on the caller frame and coro.free with null constant. Also, we need to make sure that if there are any tail calls referencing the coroutine frame, we need to remote tail call attribute, since now coroutine frame lives on the stack. Documentation and overview is here: http://llvm.org/docs/Coroutines.html. Upstreaming sequence (rough plan) 1.Add documentation. (https://reviews.llvm.org/D22603) 2.Add coroutine intrinsics. (https://reviews.llvm.org/D22659) 3.Add empty coroutine passes. (https://reviews.llvm.org/D22847) 4.Add coroutine devirtualization + tests. ab) Lower coro.resume and coro.destroy (https://reviews.llvm.org/D22998) c) Do devirtualization (https://reviews.llvm.org/D23229) 5.Add CGSCC restart trigger + tests. (https://reviews.llvm.org/D23234) 6.Add coroutine heap elision + tests. <= we are here 7.Add the rest of the logic (split into more patches) Reviewers: mehdi_amini, majnemer Subscribers: mehdi_amini, llvm-commits Differential Revision: https://reviews.llvm.org/D23245 llvm-svn: 278242
2016-08-11 00:40:39 +08:00
; Verifies that restart trigger forces IPO pipelines restart and the same
; coroutine is looked at by CoroSplit pass twice.
; REQUIRES: asserts
; RUN: opt < %s -S -O0 -enable-coroutines -debug-only=coro-split 2>&1 | FileCheck %s
; RUN: opt < %s -S -O1 -enable-coroutines -debug-only=coro-split 2>&1 | FileCheck %s
; CHECK: CoroSplit: Processing coroutine 'f' state: 0
; CHECK-NEXT: CoroSplit: Processing coroutine 'f' state: 1
define void @f() {
%id = call token @llvm.coro.id(i32 0, i8* null, i8* null, i8* null)
%size = call i32 @llvm.coro.size.i32()
%alloc = call i8* @malloc(i32 %size)
%hdl = call i8* @llvm.coro.begin(token %id, i8* %alloc)
call void @print(i32 0)
%s1 = call i8 @llvm.coro.suspend(token none, i1 false)
switch i8 %s1, label %suspend [i8 0, label %resume
i8 1, label %cleanup]
resume:
call void @print(i32 1)
br label %cleanup
cleanup:
%mem = call i8* @llvm.coro.free(token %id, i8* %hdl)
call void @free(i8* %mem)
br label %suspend
suspend:
[coroutines] Add handling for unwind coro.ends Summary: The purpose of coro.end intrinsic is to allow frontends to mark the cleanup and other code that is only relevant during the initial invocation of the coroutine and should not be present in resume and destroy parts. In landing pads coro.end is replaced with an appropriate instruction to unwind to caller. The handling of coro.end differs depending on whether the target is using landingpad or WinEH exception model. For landingpad based exception model, it is expected that frontend uses the `coro.end`_ intrinsic as follows: ``` ehcleanup: %InResumePart = call i1 @llvm.coro.end(i8* null, i1 true) br i1 %InResumePart, label %eh.resume, label %cleanup.cont cleanup.cont: ; rest of the cleanup eh.resume: %exn = load i8*, i8** %exn.slot, align 8 %sel = load i32, i32* %ehselector.slot, align 4 %lpad.val = insertvalue { i8*, i32 } undef, i8* %exn, 0 %lpad.val29 = insertvalue { i8*, i32 } %lpad.val, i32 %sel, 1 resume { i8*, i32 } %lpad.val29 ``` The `CoroSpit` pass replaces `coro.end` with ``True`` in the resume functions, thus leading to immediate unwind to the caller, whereas in start function it is replaced with ``False``, thus allowing to proceed to the rest of the cleanup code that is only needed during initial invocation of the coroutine. For Windows Exception handling model, a frontend should attach a funclet bundle referring to an enclosing cleanuppad as follows: ``` ehcleanup: %tok = cleanuppad within none [] %unused = call i1 @llvm.coro.end(i8* null, i1 true) [ "funclet"(token %tok) ] cleanupret from %tok unwind label %RestOfTheCleanup ``` The `CoroSplit` pass, if the funclet bundle is present, will insert ``cleanupret from %tok unwind to caller`` before the `coro.end`_ intrinsic and will remove the rest of the block. Reviewers: majnemer Reviewed By: majnemer Subscribers: llvm-commits, mehdi_amini Differential Revision: https://reviews.llvm.org/D25543 llvm-svn: 297223
2017-03-08 05:00:54 +08:00
call i1 @llvm.coro.end(i8* %hdl, i1 0)
ret void
[Coroutines] Part 6: Elide dynamic allocation of a coroutine frame when possible Summary: A particular coroutine usage pattern, where a coroutine is created, manipulated and destroyed by the same calling function, is common for coroutines implementing RAII idiom and is suitable for allocation elision optimization which avoid dynamic allocation by storing the coroutine frame as a static `alloca` in its caller. coro.free and coro.alloc intrinsics are used to indicate which code needs to be suppressed when dynamic allocation elision happens: ``` entry: %elide = call i8* @llvm.coro.alloc() %need.dyn.alloc = icmp ne i8* %elide, null br i1 %need.dyn.alloc, label %coro.begin, label %dyn.alloc dyn.alloc: %alloc = call i8* @CustomAlloc(i32 4) br label %coro.begin coro.begin: %phi = phi i8* [ %elide, %entry ], [ %alloc, %dyn.alloc ] %hdl = call i8* @llvm.coro.begin(i8* %phi, i32 0, i8* null, i8* bitcast ([2 x void (%f.frame*)*]* @f.resumers to i8*)) ``` and ``` %mem = call i8* @llvm.coro.free(i8* %hdl) %need.dyn.free = icmp ne i8* %mem, null br i1 %need.dyn.free, label %dyn.free, label %if.end dyn.free: call void @CustomFree(i8* %mem) br label %if.end if.end: ... ``` If heap allocation elision is performed, we replace coro.alloc with a static alloca on the caller frame and coro.free with null constant. Also, we need to make sure that if there are any tail calls referencing the coroutine frame, we need to remote tail call attribute, since now coroutine frame lives on the stack. Documentation and overview is here: http://llvm.org/docs/Coroutines.html. Upstreaming sequence (rough plan) 1.Add documentation. (https://reviews.llvm.org/D22603) 2.Add coroutine intrinsics. (https://reviews.llvm.org/D22659) 3.Add empty coroutine passes. (https://reviews.llvm.org/D22847) 4.Add coroutine devirtualization + tests. ab) Lower coro.resume and coro.destroy (https://reviews.llvm.org/D22998) c) Do devirtualization (https://reviews.llvm.org/D23229) 5.Add CGSCC restart trigger + tests. (https://reviews.llvm.org/D23234) 6.Add coroutine heap elision + tests. <= we are here 7.Add the rest of the logic (split into more patches) Reviewers: mehdi_amini, majnemer Subscribers: mehdi_amini, llvm-commits Differential Revision: https://reviews.llvm.org/D23245 llvm-svn: 278242
2016-08-11 00:40:39 +08:00
}
declare token @llvm.coro.id(i32, i8*, i8*, i8*)
declare i8* @llvm.coro.begin(token, i8*)
declare i8* @llvm.coro.free(token, i8*)
declare i32 @llvm.coro.size.i32()
declare i8 @llvm.coro.suspend(token, i1)
declare void @llvm.coro.resume(i8*)
declare void @llvm.coro.destroy(i8*)
[coroutines] Add handling for unwind coro.ends Summary: The purpose of coro.end intrinsic is to allow frontends to mark the cleanup and other code that is only relevant during the initial invocation of the coroutine and should not be present in resume and destroy parts. In landing pads coro.end is replaced with an appropriate instruction to unwind to caller. The handling of coro.end differs depending on whether the target is using landingpad or WinEH exception model. For landingpad based exception model, it is expected that frontend uses the `coro.end`_ intrinsic as follows: ``` ehcleanup: %InResumePart = call i1 @llvm.coro.end(i8* null, i1 true) br i1 %InResumePart, label %eh.resume, label %cleanup.cont cleanup.cont: ; rest of the cleanup eh.resume: %exn = load i8*, i8** %exn.slot, align 8 %sel = load i32, i32* %ehselector.slot, align 4 %lpad.val = insertvalue { i8*, i32 } undef, i8* %exn, 0 %lpad.val29 = insertvalue { i8*, i32 } %lpad.val, i32 %sel, 1 resume { i8*, i32 } %lpad.val29 ``` The `CoroSpit` pass replaces `coro.end` with ``True`` in the resume functions, thus leading to immediate unwind to the caller, whereas in start function it is replaced with ``False``, thus allowing to proceed to the rest of the cleanup code that is only needed during initial invocation of the coroutine. For Windows Exception handling model, a frontend should attach a funclet bundle referring to an enclosing cleanuppad as follows: ``` ehcleanup: %tok = cleanuppad within none [] %unused = call i1 @llvm.coro.end(i8* null, i1 true) [ "funclet"(token %tok) ] cleanupret from %tok unwind label %RestOfTheCleanup ``` The `CoroSplit` pass, if the funclet bundle is present, will insert ``cleanupret from %tok unwind to caller`` before the `coro.end`_ intrinsic and will remove the rest of the block. Reviewers: majnemer Reviewed By: majnemer Subscribers: llvm-commits, mehdi_amini Differential Revision: https://reviews.llvm.org/D25543 llvm-svn: 297223
2017-03-08 05:00:54 +08:00
declare i1 @llvm.coro.end(i8*, i1)
declare noalias i8* @malloc(i32)
declare void @print(i32)
declare void @free(i8*)