Summary:
In addMustTailToCoroResumes, we set musttail on those resume instructions that are followed by a ret instruction. This is done by simplifyTerminatorLeadingToRet which replace a sequence of branches leading to a ret with a clone of the ret.
However it forgets to remove corresponding PHI values that come from basic block of replaced branch, and may cause jumpthreading pass hangs (https://bugs.llvm.org/show_bug.cgi?id=43720)
This patch fix this issue
Test Plan:
cppcoro library with O3+flto
check-llvm
Reviewers: modocache, GorNishanov, lewissbaker
Reviewed By: modocache
Subscribers: mehdi_amini, EricWF, hiraditya, dexonsmith, jfb, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D71826
Patch by junparser (JunMa)!
If the pointer was loaded/stored before the null check, the check
is redundant and can be removed. For now the optimizers do not
remove the nullptr check, see https://gcc.godbolt.org/z/H2r5GG.
The patch allows to use more nonnull constraints. Also, it found
one more optimization in some PowerPC test. This is my first llvm
review, I am free to any comments.
Differential Revision: https://reviews.llvm.org/D71177
Summary:
Fixes https://bugs.llvm.org/show_bug.cgi?id=36578 and https://bugs.llvm.org/show_bug.cgi?id=36296.
Supersedes: https://reviews.llvm.org/D55966
One of the fundamental transformation that CoroSplit pass performs before splitting the coroutine is to find which values need to survive between suspend and resume and provide a slot for them in the coroutine frame to spill and restore the value as needed.
Coroutine frame becomes available once the storage for it was allocated and that point is marked in the pre-split coroutine with a llvm.coro.begin intrinsic.
FE normally puts all of the user-authored code that would be accessing those values after llvm.coro.begin, however, sometimes instructions accessing those values would end up prior to coro.begin. For example, writing out a value of the parameter into the alloca done by the FE or instructions that are added by the optimization passes such as SROA when it rewrites allocas.
Prior to this change, CoroSplit pass would try to move instructions that may end up accessing the values in the coroutine frame after CoroBegin. However it would run into problems (report_fatal_error) if some of the values would be used both in the allocation function (for example allocator is passed as a parameter to a coroutine) and in the use-authored body of the coroutine.
To handle this case and to simplify the instruction moving logic, this change removes all of the instruction moving. Instead, we only change the uses of the spilled values that are dominated by coro.begin and leave other instructions intact.
Before:
```
%var = alloca i32
%1 = getelementptr .. %var; ; will move this one after coro.begin
%f = call i8* @llvm.coro.begin(
```
After:
```
%var = alloca i32
%1 = getelementptr .. %var; stays put
%f = call i8* @llvm.coro.begin(
```
If we discover that there is a potential write into an alloca, prior to coro.begin we would copy its value from the alloca into the spill slot in the coroutine frame.
Before:
```
%var = alloca i32
store .. %var ; will move this one after coro.begin
%f = call i8* @llvm.coro.begin(
```
After:
```
%var = alloca i32
store .. %var ;stays put
%f = call i8* @llvm.coro.begin(
%tmp = load %var
store %tmp, %spill.slot.for.var
```
Note: This change does not handle array allocas as that is something that C++ FE does not produce, but, it can be added in the future if need arises
Reviewers: llvm-commits, modocache, ben-clayton, tks2103, rjmccall
Reviewed By: modocache
Subscribers: bartdesmet
Differential Revision: https://reviews.llvm.org/D66230
llvm-svn: 368949
The support for swifterror allocas should work in all lowerings.
The support for swifterror arguments only really works in a lowering
with prototypes where you can ensure that the prototype also has a
swifterror argument; I'm not really sure how it could possibly be
made to work in the switch lowering.
llvm-svn: 368795
A quick contrast of this ABI with the currently-implemented ABI:
- Allocation is implicitly managed by the lowering passes, which is fine
for frontends that are fine with assuming that allocation cannot fail.
This assumption is necessary to implement dynamic allocas anyway.
- The lowering attempts to fit the coroutine frame into an opaque,
statically-sized buffer before falling back on allocation; the same
buffer must be provided to every resume point. A buffer must be at
least pointer-sized.
- The resume and destroy functions have been combined; the continuation
function takes a parameter indicating whether it has succeeded.
- Conversely, every suspend point begins its own continuation function.
- The continuation function pointer is directly returned to the caller
instead of being stored in the frame. The continuation can therefore
directly destroy the frame when exiting the coroutine instead of having
to leave it in a defunct state.
- Other values can be returned directly to the caller instead of going
through a promise allocation. The frontend provides a "prototype"
function declaration from which the type, calling convention, and
attributes of the continuation functions are taken.
- On the caller side, the frontend can generate natural IR that directly
uses the continuation functions as long as it prevents IPO with the
coroutine until lowering has happened. In combination with the point
above, the frontend is almost totally in charge of the ABI of the
coroutine.
- Unique-yield coroutines are given some special treatment.
llvm-svn: 368788
For consistency with normal instructions and clarity when reading IR,
it's best to print the %0, %1, ... names of function arguments in
definitions.
Also modifies the parser to accept IR in that form for obvious reasons.
llvm-svn: 367755
Summary:
CoroFrame was not considering static array allocas, and was only ever reserving a single element in the coroutine frame.
This meant that stores to the non-zero'th element would corrupt later frame data.
Store static array allocas as field arrays in the coroutine frame.
Added test.
Committed by Gor Nishanov on behalf of ben-clayton
Reviewers: GorNishanov, modocache
Reviewed By: GorNishanov
Subscribers: Orlando, capn, EricWF, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D61372
llvm-svn: 360636
As it's causing some bot failures (and per request from kbarton).
This reverts commit r358543/ab70da07286e618016e78247e4a24fcb84077fda.
llvm-svn: 358546
Summary:
Depends on https://reviews.llvm.org/D59069.
https://bugs.llvm.org/show_bug.cgi?id=40979 describes a bug in which the
-coro-split pass would assert that a use was across a suspend point from
a definition. Normally this would mean that a value would "spill" across
a suspend point and thus need to be stored in the coroutine frame. However,
in this case the use was unreachable, and so it would not be necessary
to store the definition on the frame.
To prevent the assert, simply remove unreachable basic blocks from a
coroutine function before computing spills. This avoids the assert
reported in PR40979.
Reviewers: GorNishanov, tks2103
Reviewed By: GorNishanov
Subscribers: EricWF, jdoerfert, llvm-commits, lewissbaker
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59068
llvm-svn: 355852
compiler identification lines in test-cases.
(Doing so only because it's then easier to search for references which
are actually important and need fixing.)
llvm-svn: 351200
Summary:
Enable suspend point simplification for cases where:
* coro.save and coro.suspend are in different basic blocks
* where there are intervening intrinsics
Reviewers: modocache, tks2103, lewissbaker
Reviewed By: modocache
Subscribers: EricWF, llvm-commits
Differential Revision: https://reviews.llvm.org/D55160
llvm-svn: 348897
Summary:
https://bugs.llvm.org/show_bug.cgi?id=34897 demonstrates an incorrect
coroutine frame allocation elision in the coro-elide pass. The elision
is performed on the basis that the SSA variables from all llvm.coro.begin
are directly referenced in subsequent llvm.coro.destroy instructions.
However, this ignores the fact that the function may exit through paths
that do not run these destroy instructions. In the sample program from
PR34897, for example, the llvm.coro.destroy instruction is only
executed in exception handling code. When the coroutine function exits
normally, llvm.coro.destroy is not called. Eliding the allocation in
this case causes a subsequent reference to the coroutine handle from
outside of the function to access freed memory.
To fix the issue, when finding an llvm.coro.destroy for each llvm.coro.begin,
only consider llvm.coro.destroy that are executed along non-exceptional paths.
Test Plan:
1. Download the sample program from
https://bugs.llvm.org/show_bug.cgi?id=34897, compile it with
`clang++ -fcoroutines-ts -stdlib=libc++ -std=c++1z -O2`, and run it.
It should print `"run1\ncheck1\nrun2\ncheck2"` and then exit
successfully.
2. Compile https://godbolt.org/g/mCKfnr and confirm it is still
optimized to a single instruction, 'return 1190'.
3. `check-llvm`
Reviewers: rsmith, GorNishanov, eric_niebler
Reviewed By: GorNishanov
Subscribers: andrewrk, lewissbaker, EricWF, llvm-commits
Differential Revision: https://reviews.llvm.org/D43242
llvm-svn: 332077
In order to set breakpoints on labels and list source code around
labels, we need collect debug information for labels, i.e., label
name, the function label belong, line number in the file, and the
address label located. In order to keep these information in LLVM
IR and to allow backend to generate debug information correctly.
We create a new kind of metadata for labels, DILabel. The format
of DILabel is
!DILabel(scope: !1, name: "foo", file: !2, line: 3)
We hope to keep debug information as much as possible even the
code is optimized. So, we create a new kind of intrinsic for label
metadata to avoid the metadata is eliminated with basic block.
The intrinsic will keep existing if we keep it from optimized out.
The format of the intrinsic is
llvm.dbg.label(metadata !1)
It has only one argument, that is the DILabel metadata. The
intrinsic will follow the label immediately. Backend could get the
label metadata through the intrinsic's parameter.
We also create DIBuilder API for labels to be used by Frontend.
Frontend could use createLabel() to allocate DILabel objects, and use
insertLabel() to insert llvm.dbg.label intrinsic in LLVM IR.
Differential Revision: https://reviews.llvm.org/D45024
Patch by Hsiangkai Wang.
llvm-svn: 331841
Summary:
If an alloca need to be stored in the coroutine frame and it has an alignment specified and the alignment does not match the natural alignment of the alloca type. Insert appropriate padding into the coroutine frame to make sure that it gets requested alignment.
For example for a packet type (which natural alignment is 1), but alloca alignment is 8, we may need to insert a padding field with required number of bytes to make sure it is properly aligned.
```
%PackedStruct = type <{ i64 }>
...
%data = alloca %PackedStruct, align 8
```
If the previous field in the coroutine frame had alignment 2, we would have [6 x i8] inserted before %PackedStruct in the coroutine frame:
```
%f.Frame = type { ..., i16, [6 x i8], %PackedStruct }
```
Reviewers: rnk, lewissbaker, modocache
Reviewed By: modocache
Subscribers: EricWF, llvm-commits
Differential Revision: https://reviews.llvm.org/D45221
llvm-svn: 329112
Summary:
When attempting to split a coroutine with 'hidden' visibility (for
example, a C++ coroutine that is inlined when compiled with the option
'-fvisibility-inlines-hidden'), LLVM would hit an assertion in
include/llvm/IR/GlobalValue.h:240: "local linkage requires default
visibility". The issue is that the visibility is copied from the source
of the function split in the `CloneFunctionInto` function, but the linkage
is not. To fix, create the new function first with external linkage,
then copy the linkage from the original function *after* `CloneFunctionInto`
is called.
Since `GlobalValue::setLinkage` in turn calls `maybeSetDsoLocal`, the
explicit call to `setDSOLocal` can be removed in CoroSplit.cpp.
Test Plan: check-llvm
Reviewers: GorNishanov, lewissbaker, EricWF, majnemer, rnk
Reviewed By: rnk
Subscribers: llvm-commits, eric_niebler
Differential Revision: https://reviews.llvm.org/D44185
llvm-svn: 329033
Summary:
A recent addition to Coroutines TS (https://wg21.link/p0913) adds a pre-defined coroutine noop_coroutine that does nothing.
To implement this feature, we implemented an llvm.coro.noop intrinsic that returns a coroutine handle to a coroutine that does nothing when resumed or destroyed.
Reviewers: EricWF, modocache, rnk, lewissbaker
Reviewed By: modocache
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D45114
llvm-svn: 328986
Summary:
The behavior described in Coroutines TS `[dcl.fct.def.coroutine]/7`
allows coroutine parameters to be passed into allocator functions.
The instructions to store values into the alloca'd parameters must not
be moved past the frame allocation, otherwise uninitialized values are
passed to the allocator.
Test Plan: `check-llvm`
Reviewers: rsmith, GorNishanov, eric_niebler
Reviewed By: GorNishanov
Subscribers: compnerd, EricWF, llvm-commits
Differential Revision: https://reviews.llvm.org/D43000
llvm-svn: 325285
Summary:
Add musttail to any resume instructions that is immediately followed by a
suspend (i.e. ret). We do this even in -O0 to support guaranteed tail call
for symmetrical coroutine control transfer (C++ Coroutines TS extension).
This transformation is done only in the resume part of the coroutine that has
identical signature and calling convention as the coro.resume call.
Reviewers: GorNishanov
Reviewed By: GorNishanov
Subscribers: EricWF, majnemer, llvm-commits
Differential Revision: https://reviews.llvm.org/D37125
llvm-svn: 311751
Summary:
If a coroutine outer calls another coroutine inner and the inner coroutine body is inlined into the outer, coro.begin from the inner coroutine should be considered for spilling if accessed across suspends.
Prior to this change, coroutine frame building code was not considering any coro.begins for spilling.
With this change, we only ignore coro.begin for the current coroutine, but, any coro.begins that were inlined into the current coroutine are eligible for spills.
Fixes PR34267
Reviewers: GorNishanov
Subscribers: qcolombet, llvm-commits, EricWF
Differential Revision: https://reviews.llvm.org/D37062
llvm-svn: 311556
There is no situation where this rarely-used argument cannot be
substituted with a DIExpression and removing it allows us to simplify
the DWARF backend. Note that this patch does not yet remove any of
the newly dead code.
rdar://problem/33580047
Differential Revision: https://reviews.llvm.org/D35951
llvm-svn: 309426
Summary:
Optimization passes may remove llvm.coro.suspend intrinsic while leaving matching llvm.coro.save intrinsic orphaned.
Make sure we clean up orphaned coro.saves. The bug manifested with a crash similar to this:
```
llvm_unreachable("Unknown type!");
llvm::MVT::getVT (Ty=0x489518, HandleUnknown=false)
llvm::EVT::getEVT
llvm::TargetLoweringBase::getValueType
llvm::ComputeValueVTs
llvm::SelectionDAGBuilder::visitTargetIntrinsic
```
Reviewers: GorNishanov
Subscribers: EricWF, llvm-commits
Differential Revision: https://reviews.llvm.org/D33817
llvm-svn: 304518
Summary:
I believe https://reviews.llvm.org/rL302576 introduced two bugs:
1) it produces duplicate distinct variables for every: dbg.value describing the same variable.
To fix the problme I switched form getDistinct() to get() in DebugLoc.cpp: auto reparentVar = [&](DILocalVariable *Var) {
return DILocalVariable::getDistinct(
2) It passes NewFunction plain name as a linkagename parameter to Subprogram constructor. Breaks assert in:
|| DeclLinkageName.empty()) || LinkageName == DeclLinkageName) && "decl has a linkage name and it is different"' failed.
#9 0x00007f5010261b75 llvm::DwarfUnit::applySubprogramDefinitionAttributes(llvm::DISubprogram const*, llvm::DIE&) /home/gor/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:1173:3
#
(Edit: reproducer added)
Here how https://reviews.llvm.org/rL302576 broke coroutine debug info.
Coroutine body of the original function is split into several parts by cloning and removing unneeded code.
All parts describe the original function and variables present in the original function.
For a simple case, prior to Split, original function has these two blocks:
```
PostSpill: ; preds = %AllocaSpillBB
call void @llvm.dbg.value(metadata i32 %x, i64 0, metadata !14, metadata !15), !dbg !13
store i32 %x, i32* %x.addr, align 4
...
and
sw.epilog: ; preds = %sw.bb
%x.addr.reload.addr = getelementptr inbounds %f.Frame, %f.Frame* %FramePtr, i32 0, i32 4, !dbg !20
%4 = load i32, i32* %x.addr.reload.addr, align 4, !dbg !20
call void @llvm.dbg.value(metadata i32 %4, i64 0, metadata !14, metadata !15), !dbg !13!14 = !DILocalVariable(name: "x", arg: 1, scope: !6, file: !7, line: 55, type: !11)
```
Note that in two blocks different expression represent the same original user variable X.
Before rL302576, for every cloned function there was exactly one cloned DILocalVariable(name: "x" as in:
```
define i8* @f(i32 %x) #0 !dbg !6 {
...
!6 = distinct !DISubprogram(name: "f", scope: !7, file: !7, line: 55, type: !8, isLocal: false, isDefinition: true, scopeLine: 55, flags: DIFlagPrototyped,
...
!14 = !DILocalVariable(name: "x", arg: 1, scope: !6, file: !7, line: 55, type: !11)
define internal fastcc void @f.resume(%f.Frame* %FramePtr) #0 !dbg !25 {
...
!25 = distinct !DISubprogram(name: "f", scope: !7, file: !7, line: 55, type: !8, isLocal: false, isDefinition: true, scopeLine: 55, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
!28 = !DILocalVariable(name: "x", arg: 1, scope: !25, file: !7, line: 55, type: !11)
```
After rL302576, for every cloned function there were as many DILocalVariable(name: "x" as there were "call void @llvm.dbg.value" for that variable.
This was causing asserts in VerifyDebugInfo and AssemblyPrinter.
Example:
```
!27 = distinct !DISubprogram(name: "f", linkageName: "f.resume", scope: !7, file: !7, line: 55, type: !8, isLocal: false, isDefinition: true, scopeLine: 55,
!29 = distinct !DILocalVariable(name: "x", arg: 1, scope: !27, file: !7, line: 55, type: !11)
!39 = distinct !DILocalVariable(name: "x", arg: 1, scope: !27, file: !7, line: 55, type: !11)
!41 = distinct !DILocalVariable(name: "x", arg: 1, scope: !27, file: !7, line: 55, type: !11)
```
Second problem:
Prior to rL302576, all clones were described by DISubprogram referring to original function.
```
define i8* @f(i32 %x) #0 !dbg !6 {
...
!6 = distinct !DISubprogram(name: "f", scope: !7, file: !7, line: 55, type: !8, isLocal: false, isDefinition: true, scopeLine: 55, flags: DIFlagPrototyped,
define internal fastcc void @f.resume(%f.Frame* %FramePtr) #0 !dbg !25 {
...
!25 = distinct !DISubprogram(name: "f", scope: !7, file: !7, line: 55, type: !8, isLocal: false, isDefinition: true, scopeLine: 55, flags: DIFlagPrototyped,
```
After rL302576, DISubprogram for clones is of two minds, plain name refers to the original name, linkageName refers to plain name of the clone.
```
!27 = distinct !DISubprogram(name: "f", linkageName: "f.resume", scope: !7, file: !7, line: 55, type: !8, isLocal: false, isDefinition: true, scopeLine: 55,
```
I think the assumption in AsmPrinter is that both name and linkageName should refer to the same entity. It asserts here when they are not:
```
|| DeclLinkageName.empty()) || LinkageName == DeclLinkageName) && "decl has a linkage name and it is different"' failed.
#9 0x00007f5010261b75 llvm::DwarfUnit::applySubprogramDefinitionAttributes(llvm::DISubprogram const*, llvm::DIE&) /home/gor/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp:1173:3
```
After this fix, behavior (with respect to coroutines) reverts to exactly as it was before and therefore making them debuggable again, or even more importantly, compilable, with "-g"
Reviewers: dblaikie, echristo, aprantl
Reviewed By: dblaikie
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D33614
llvm-svn: 304079
Summary:
Frontend generates store instructions after allocas, for example:
```
define i8* @f(i64 %this) "coroutine.presplit"="1" personality i32 0 {
entry:
%this.addr = alloca i64
store i64 %this, i64* %this.addr
..
%hdl = call i8* @llvm.coro.begin(token %id, i8* %alloc)
```
Such instructions may require spilling into coro.frame, but, coro-frame address is only available after coro.begin and thus needs to be moved after coro.begin.
The only instructions that should not be moved are the arguments of coro.begin and all of their operands.
Reviewers: GorNishanov, majnemer
Reviewed By: GorNishanov
Subscribers: llvm-commits, EricWF
Differential Revision: https://reviews.llvm.org/D33527
llvm-svn: 303825
If we need to spill the result of the PHI instruction, we insert the spill after
all of the PHIs and EHPads, however, in a catchswitch block there is no
room to insert the spill. Make room by splitting away catchswitch into a separate
block.
Before the fix:
catch.dispatch:
%val = phi i32 [ 1, %if.then ], [ 2, %if.else ]
%switch = catchswitch within none [label %catch] unwind label %cleanuppad
After:
catch.dispatch:
%val = phi i32 [ 1, %if.then ], [ 2, %if.else ]
%tok = cleanuppad within none []
; spill goes here
cleanupret from %tok unwind label %catch.dispatch.switch
catch.dispatch.switch:
%switch = catchswitch within none [label %catch] unwind label %cleanuppad
https://reviews.llvm.org/D31846
llvm-svn: 303232
Summary:
RewritePHIs algorithm used in building of CoroFrame inserts a placeholder
```
%placeholder = phi [%val]
```
on every edge leading to a block starting with PHI node with multiple incoming edges,
so that if one of the incoming values was spilled and need to be reloaded, we have a
place to insert a reload. We use SplitEdge helper function to split the incoming edge.
SplitEdge function does not deal with unwind edges comping into a block with an EHPad.
This patch adds an ehAwareSplitEdge function that can correctly split the unwind edge.
For landing pads, we clone the landing pad into every edge block and replace the original
landing pad with a PHI collection the values from all incoming landing pads.
For WinEH pads, we keep the original EHPad in place and insert cleanuppad/cleapret in the
edge blocks.
Reviewers: majnemer, rnk
Reviewed By: majnemer
Subscribers: EricWF, llvm-commits
Differential Revision: https://reviews.llvm.org/D31845
llvm-svn: 303172
coro-split-after-phi.ll test was flaky due to non-determinism in
the coroutine frame construction that was sorting the spill
vector using a pointer to a def as a part of the key.
The sorting was intended to make sure that spills for the same def
are kept together, however, we populate the vector by processing
defs in order, so the spill entires will end up together anyways.
This change removes spill sorting and restores the determinism
in the test.
llvm-svn: 299809
Summary:
Fix a bug where we were inserting a spill in between the PHIs in the beginning of the block.
Consider this fragment:
```
begin:
%phi1 = phi i32 [ 0, %entry ], [ 2, %alt ]
%phi2 = phi i32 [ 1, %entry ], [ 3, %alt ]
%sp1 = call i8 @llvm.coro.suspend(token none, i1 false)
switch i8 %sp1, label %suspend [i8 0, label %resume
i8 1, label %cleanup]
resume:
call i32 @print(i32 %phi1)
```
Unless we are spilling the argument or result of the invoke, we were always inserting the spill immediately following the instruction.
The fix adds a check that if the spilled instruction is a PHI Node, select an appropriate insert point with `getFirstInsertionPt()` that
skips all the PHI Nodes and EH pads.
Reviewers: majnemer, rnk
Reviewed By: rnk
Subscribers: qcolombet, EricWF, llvm-commits
Differential Revision: https://reviews.llvm.org/D31799
llvm-svn: 299771
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
Summary:
When we decide that the result of the invoke instruction need to be spilled, we need to insert the spill into a block that is on the normal edge coming out of the invoke instruction. (Prior to this change the code would insert the spill immediately after the invoke instruction, which breaks the IR, since invoke is a terminator instruction).
In the following example, we will split the edge going into %cont and insert the spill there.
```
%r = invoke double @print(double 0.0) to label %cont unwind label %pad
cont:
%0 = call i8 @llvm.coro.suspend(token none, i1 false)
switch i8 %0, label %suspend [i8 0, label %resume
i8 1, label %cleanup]
resume:
call double @print(double %r)
```
Reviewers: majnemer
Reviewed By: majnemer
Subscribers: mehdi_amini, llvm-commits, EricWF
Differential Revision: https://reviews.llvm.org/D29102
llvm-svn: 293006
Summary:
If heap allocation of a coroutine is elided, we need to make sure that we will update an address stored in the coroutine frame from f.destroy to f.cleanup.
Before this change, CoroSplit synthesized these stores after coro.begin:
```
store void (%f.Frame*)* @f.resume, void (%f.Frame*)** %resume.addr
store void (%f.Frame*)* @f.destroy, void (%f.Frame*)** %destroy.addr
```
In those cases where we did heap elision, but were not able to devirtualize all indirect calls, destroy call will attempt to "free" the coroutine frame stored on the stack. Oops.
Now we use select to put an appropriate coroutine subfunction in the destroy slot. As bellow:
```
store void (%f.Frame*)* @f.resume, void (%f.Frame*)** %resume.addr
%0 = select i1 %need.alloc, void (%f.Frame*)* @f.destroy, void (%f.Frame*)* @f.cleanup
store void (%f.Frame*)* %0, void (%f.Frame*)** %destroy.addr
```
Reviewers: majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D25377
llvm-svn: 283625
Summary:
In the case below, %Result.i19 is defined between coro.save and coro.suspend and used after coro.suspend. We need to correctly place such a value into the coroutine frame.
```
%save = call token @llvm.coro.save(i8* null)
%Result.i19 = getelementptr inbounds %"struct.lean_future<int>::Awaiter", %"struct.lean_future<int>::Awaiter"* %ref.tmp7, i64 0, i32 0
%suspend = call i8 @llvm.coro.suspend(token %save, i1 false)
switch i8 %suspend, label %exit [
i8 0, label %await.ready
i8 1, label %exit
]
await.ready:
%val = load i32, i32* %Result.i19
```
Reviewers: majnemer
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D24418
llvm-svn: 282902
Summary:
Without the fix, if there was a function inlined into the coroutine with debug information, CloneFunctionInto(NewF, &F, VMap, /*ModuleLevelChanges=*/true, Returns); would duplicate all of the debug information including the DICompileUnit.
We know use VMap to indicate that debug metadata for a File, Unit and FunctionType should not be duplicated when we creating clones that will become f.resume, f.destroy and f.cleanup.
Reviewers: majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D24417
llvm-svn: 282899
Summary: Not all coro.subfn.addr intrinsics can be eliminated in CoroElide through devirtualization. Those that remain need to be lowered in CoroCleanup.
Reviewers: majnemer
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D24412
llvm-svn: 282897
Summary:
If coroutine has no suspend points, remove heap allocation and turn a coroutine into a normal function.
Also, if a pattern is detected that coroutine resumes or destroys itself prior to coro.suspend call, turn the suspend point into a simple jump to resume or cleanup label. This pattern occurs when coroutines are used to propagate errors in functions that return expected<T>.
Reviewers: majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D24408
llvm-svn: 282414
Summary:
If one of the uses of the value is a single edge PHINode, handle it.
Original:
%val = something
<suspend>
%p = PHINode [%val]
After Spill + Part13:
%val = something
%slot = gep val.spill.slot
store %val, %slot
<suspend>
%p = load %slot
Plus tiny fixes/changes:
* use correct index for coro.free in CoroCleanup
* fixup id parameter in coro.free to allow authoring coroutine in plain C with __builtins
Reviewers: majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D24242
llvm-svn: 281020
Summary:
Move early uses of spilled variables after CoroBegin.
For example, if a parameter had address taken, we may end up with the code
like:
define @f(i32 %n) {
%n.addr = alloca i32
store %n, %n.addr
...
call @coro.begin
This patch fixes the problem by moving uses of spilled variables after CoroBegin.
Reviewers: majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D24234
llvm-svn: 280678
Summary:
A frontend may designate a particular suspend to be final, by setting the second argument of the coro.suspend intrinsic to true. Such a suspend point has two properties:
* it is possible to check whether a suspended coroutine is at the final suspend point via coro.done intrinsic;
* a resumption of a coroutine stopped at the final suspend point leads to undefined behavior. The only possible action for a coroutine at a final suspend point is destroying it via coro.destroy intrinsic.
This patch adds final suspend handling logic to CoroEarly and CoroSplit passes.
Now, the final suspend point example from docs\Coroutines.rst compiles and produces expected result (see test/Transform/Coroutines/ex5.ll).
Reviewers: majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D24068
llvm-svn: 280646
Summary:
1) CoroEarly now lowers llvm.coro.promise intrinsic that allows to obtain
a coroutine promise pointer from a coroutine frame and vice versa.
2) CoroFrame now interprets Promise argument of llvm.coro.begin to
place CoroutinPromise alloca at a deterministic offset from the coroutine frame.
Now, the coroutine promise example from docs\Coroutines.rst compiles and produces expected result (see test/Transform/Coroutines/ex4.ll).
Reviewers: majnemer
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23993
llvm-svn: 280184
Summary:
[Coroutines] Part 9: Add cleanup subfunction.
This patch completes coroutine heap allocation elision. Now, the heap elision example from docs\Coroutines.rst compiles and produces expected result (see test/Transform/Coroutines/ex3.ll)
Intrinsic Changes:
* coro.free gets a token parameter tying it to coro.id to allow reliably discovering all coro.frees associated with a particular coroutine.
* coro.id gets an extra parameter that points back to a coroutine function. This allows to check whether a coro.id describes the enclosing function or it belongs to a different function that was later inlined.
CoroSplit now creates three subfunctions:
# f$resume - resume logic
# f$destroy - cleanup logic, followed by a deallocation code
# f$cleanup - just the cleanup code
CoroElide pass during devirtualization replaces coro.destroy with either f$destroy or f$cleanup depending whether heap elision is performed or not.
Other fixes, improvements:
* Fixed buglet in Shape::buildFrame that was not creating coro.save properly if coroutine has more than one suspend point.
* Switched to using variable width suspend index field (no longer limited to 32 bit index field can be as little as i1 or as large as i<whatever-size_t-is>)
Reviewers: majnemer
Subscribers: llvm-commits, mehdi_amini
Differential Revision: https://reviews.llvm.org/D23844
llvm-svn: 279971
Summary:
This patch adds coroutine frame building algorithm. Now, simple coroutines such as ex0.ll and ex1.ll (first examples from docs\Coroutines.rst can be compiled).
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)
...
7. Split coroutine into subfunctions. (https://reviews.llvm.org/D23461)
8. Coroutine Frame Building algorithm <= we are here
9. Add f.cleanup subfunction.
10+. The rest of the logic
Reviewers: majnemer
Subscribers: mehdi_amini, llvm-commits
Differential Revision: https://reviews.llvm.org/D23586
llvm-svn: 279609
Brian Gesiak