This patch is to address https://bugs.llvm.org/show_bug.cgi?id=49916.
When the size of an alloca is 0, it will trigger an assertion in OptimizedStructLayout when being added to the frame.
Fix it by not adding it at all. We return index 0 (beginning of the frame) for all 0-sized allocas.
Differential Revision: https://reviews.llvm.org/D101841
Previous build failures were caused by an error in bitcode reading and
writing for DIArgList metadata, which has been fixed in e5d844b587.
There were also some unnecessary asserts that were being triggered on
certain builds, which have been removed.
This reverts commit dad5caa59e.
Summary: The original logic seems to be we could collecting a CoroBegin
if one of the terminators could be dominated by one of coro.destroy,
which doesn't make sense.
This patch rewrites the logics to collect CoroBegin if all of
terminators are dominated by one coro.destroy. If there is no such
coro.destroy, we would call hasEscapePath to evaluate if we should
collect it.
Test Plan: check-llvm
Reviewed by: lxfind
Differential Revision: https://reviews.llvm.org/D100614
This reverts commit fa6b54c44a.
The commited patch broke mlir tests. It seems that mlir tests depend on coroutine function properties set in CoroEarly pass.
Presplit coroutines cannot be inlined. During AlwaysInliner we check if a function is a presplit coroutine, if so we skip inlining.
The presplit coroutine attributes are set in CoroEarly pass.
However in O0 pipeline, AlwaysInliner runs before CoroEarly, so the attribute isn't set yet and will still inline the coroutine.
This causes Clang to crash: https://bugs.llvm.org/show_bug.cgi?id=49920
To fix this, we set the attributes in the Clang front-end instead of in CoroEarly pass.
Reviewed By: rjmccall, ChuanqiXu
Differential Revision: https://reviews.llvm.org/D100282
Presplit coroutines cannot be inlined. During AlwaysInliner we check if a function is a presplit coroutine, if so we skip inlining.
The presplit coroutine attributes are set in CoroEarly pass.
However in O0 pipeline, AlwaysInliner runs before CoroEarly, so the attribute isn't set yet and will still inline the coroutine.
This causes Clang to crash: https://bugs.llvm.org/show_bug.cgi?id=49920
Differential Revision: https://reviews.llvm.org/D100282
This patch updates the linkage name in the DISubprogram of coro-split
functions, which is particularly important for Swift, where the
funclets have a special name mangling. This patch does not affect C++
coroutines, since the DW_AT_specification is expected to hold the
(original) linkage name. I believe this is mostly due to limitations
in AsmPrinter, so we might be able to relax this restriction in the
future.
Differential Revision: https://reviews.llvm.org/D99693
Main reason is preparation to transform AliasResult to class that contains
offset for PartialAlias case.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D98027
Summary:
The function SplitCriticalEdge (called by SplitEdge) can return a nullptr in
cases where the edge is a critical. SplitEdge uses SplitCriticalEdge assuming it
can always split all critical edges, which is an incorrect assumption.
The three cases where the function SplitCriticalEdge will return a nullptr is:
1. DestBB is an exception block
2. Options.IgnoreUnreachableDests is set to true and
isa(DestBB->getFirstNonPHIOrDbgOrLifetime()) is not equal to a nullptr
3. LoopSimplify form must be preserved (Options.PreserveLoopSimplify is true)
and it cannot be maintained for a loop due to indirect branches
For each of these situations they are handled in the following way:
1. Modified the function ehAwareSplitEdge originally from
llvm/lib/Transforms/Coroutines/CoroFrame.cpp to handle the cases when the DestBB
is an exception block. This function is called directly in SplitEdge.
SplitEdge does not call SplitCriticalEdge in this case
2. Options.IgnoreUnreachableDests is set to false by default, so this situation
does not apply.
3. Return a nullptr in this situation since the SplitCriticalEdge also returned
nullptr. Nothing we can do in this case.
Reviewed By: asbirlea
Differential Revision:https://reviews.llvm.org/D94619
Summary: Try to insert dbg.declare to entry.resume basic block in resume
function. In this way, we could print alloca such as __promise in
gdb/lldb under O2, which would be beneficial to debug coroutine program.
Test Plan: check-llvm
Reviewed by: aprantl
Differential Revision: https://reviews.llvm.org/D96938
Fixed section of code that iterated through a SmallDenseMap and added
instructions in each iteration, causing non-deterministic code; replaced
SmallDenseMap with MapVector to prevent non-determinism.
This reverts commit 01ac6d1587.
This caused non-deterministic compiler output; see comment on the
code review.
> This patch updates the various IR passes to correctly handle dbg.values with a
> DIArgList location. This patch does not actually allow DIArgLists to be produced
> by salvageDebugInfo, and it does not affect any pass after codegen-prepare.
> Other than that, it should cover every IR pass.
>
> Most of the changes simply extend code that operated on a single debug value to
> operate on the list of debug values in the style of any_of, all_of, for_each,
> etc. Instances of setOperand(0, ...) have been replaced with with
> replaceVariableLocationOp, which takes the value that is being replaced as an
> additional argument. In places where this value isn't readily available, we have
> to track the old value through to the point where it gets replaced.
>
> Differential Revision: https://reviews.llvm.org/D88232
This reverts commit df69c69427.
This patch improves salvageDebugInfoImpl by allowing it to salvage arithmetic
operations with two or more non-const operands; this includes the GetElementPtr
instruction, and most Binary Operator instructions. These salvages produce
DIArgList locations and are only valid for dbg.values, as currently variadic
DIExpressions must use DW_OP_stack_value. This functionality is also only added
for salvageDebugInfoForDbgValues; other functions that directly call
salvageDebugInfoImpl (such as in ISel or Coroutine frame building) can be
updated in a later patch.
Differential Revision: https://reviews.llvm.org/D91722
This patch updates the various IR passes to correctly handle dbg.values with a
DIArgList location. This patch does not actually allow DIArgLists to be produced
by salvageDebugInfo, and it does not affect any pass after codegen-prepare.
Other than that, it should cover every IR pass.
Most of the changes simply extend code that operated on a single debug value to
operate on the list of debug values in the style of any_of, all_of, for_each,
etc. Instances of setOperand(0, ...) have been replaced with with
replaceVariableLocationOp, which takes the value that is being replaced as an
additional argument. In places where this value isn't readily available, we have
to track the old value through to the point where it gets replaced.
Differential Revision: https://reviews.llvm.org/D88232
This patch updates DbgVariableIntrinsics to support use of a DIArgList for the
location operand, resulting in a significant change to its interface. This patch
does not update all IR passes to support multiple location operands in a
dbg.value; the only change is to update the DbgVariableIntrinsic interface and
its uses. All code outside of the intrinsic classes assumes that an intrinsic
will always have exactly one location operand; they will still support
DIArgLists, but only if they contain exactly one Value.
Among other changes, the setOperand and setArgOperand functions in
DbgVariableIntrinsic have been made private. This is to prevent code from
setting the operands of these intrinsics directly, which could easily result in
incorrect/invalid operands being set. This does not prevent these functions from
being called on a debug intrinsic at all, as they can still be called on any
CallInst pointer; it is assumed that any code directly setting the operands on a
generic call instruction is doing so safely. The intention for making these
functions private is to prevent DIArgLists from being overwritten by code that's
naively trying to replace one of the Values it points to, and also to fail fast
if a DbgVariableIntrinsic is updated to use a DIArgList without a valid
corresponding DIExpression.
This patch updates the scope line to point to the suspend point. This
makes the first address in the function point to the first source line
in the resume function rather than the function declaration. Without
this the line table "jumps" from the beginning of the function to the
suspend point at the beginning.
rdar://73386346
Differential Revision: https://reviews.llvm.org/D97345
Before we used the same argument as the entry point. The resume partial
function might want to use a different ABI for its context argument
Differential Revision: https://reviews.llvm.org/D97333
This doesn't actually reproduce with a dbg.declare(i8* null, ...)
which produces a non-null null Value, but I have seen this show up in
crash logs. I'm suspecting that there may be another pass forcibly
setting the operand to a nullptr.
In the existing logic, we look at the lifetime.start marker of each alloca, and check all uses of the alloca, to see if any pair of the lifetime marker and an use of alloca crosses suspension point.
This approach is unfortunately incorrect. An use of alloca does not need to be a direct use, but can be an indirect use through alias.
Only checking direct uses can miss cases where indirect uses are crossing suspension point.
This can be demonstrated in the newly added test case 007.
In the test case, both x and y are only directly used prior to suspend, but they are captured into an alias, merged through a PHINode (so they couldn't be materialized), and used after CoroSuspend.
If we only check whether the lifetime starts cross suspension points with direct uses, we will put the allocas to the stack, and then capture their addresses in the frame.
Instead of fixing it in D96441 and D96566, this patch takes a different approach which I think is better.
We still checks the lifetime info in the same way as before, but with two differences:
1. The collection of liftime.start is moved into AllocaUseVisitor to make the logic more concentrated.
2. When looking at lifetime.start and use pairs, we not only checks the direct uses as before, but in this patch we check all uses collected by AllocaUseVisitor, which would include all indirect uses through alias. This will make the analysis more accurate without throwing away the lifetime optimization.
Differential Revision: https://reviews.llvm.org/D96922
The new intrinsic replaces the size in one specified AsyncFunctionPointer with
the size in another. This ability is necessary for functions which merely
forward to async functions such as those defined for partial applications.
Reviewed By: aschwaighofer
Differential Revision: https://reviews.llvm.org/D97229
As discussed in D94834, we don't really need to do complicated analysis. It's safe to just drop the tail call attribute.
Differential Revision: https://reviews.llvm.org/D96926
Also don't call function to update the call graph if there are no
clones. The function will fail.
rdar://74277860
Differential Revision: https://reviews.llvm.org/D96620
This commit fixes how metadata is handled in CloneModule to be sound,
and improves how it's handled in CloneFunctionInto (although the latter
is still awkward when called within a module).
Ruiling Song pointed out in PR48841 that CloneModule was changed to
unsoundly use the RF_ReuseAndMutateDistinctMDs flag (renamed in
fa35c1f80f for clarity). This flag papered
over a crash caused by other various changes made to CloneFunctionInto
over the past few years that made it unsound to use cloning between
different modules.
(This commit partially addresses PR48841, fixing the repro from
preprocessed source but not textual IR. MDNodeMapper::mapDistinctNode
became unsound in df763188c9 and this
commit does not address that regression.)
RF_ReuseAndMutateDistinctMDs is designed for the IRMover to use,
avoiding unnecessary clones of all referenced metadata when linking
between modules (with IRMover, the source module is discarded after
linking). It never makes sense to use when you're not discarding the
source. This commit drops its incorrect use in CloneModule.
Sadly, the right thing to do with metadata when cloning a function is
complicated, and this patch doesn't totally fix it.
The first problem is that there are two different types of referenceable
metadata and it's not obvious what to with one of them when remapping.
- `!0 = !{!1}` is metadata's version of a constant. Programatically it's
called "uniqued" (probably a better term would be "constant") because,
like `ConstantArray`, it's stored in uniquing tables. Once it's
constructed, it's illegal to change its arguments.
- `!0 = distinct !{!1}` is a bit closer to a global variable. It's legal
to change the operands after construction.
What should be done with distinct metadata when cloning functions within
the same module?
- Should new, cloned nodes be created?
- Should all references point to the same, old nodes?
The answer depends on whether that metadata is effectively owned by a
function.
And that's the second problem. Referenceable metadata's ownership model
is not clear or explicit. Technically, it's all stored on an
LLVMContext. However, any metadata that is `distinct`, that transitively
references a `distinct` node, or that transitively references a
GlobalValue is specific to a Module and is effectively owned by it. More
specifically, some metadata is effectively owned by a specific Function
within a module.
Effectively function-local metadata was introduced somewhere around
c10d0e5ccd, which made it illegal for two
functions to share a DISubprogram attachment.
When cloning a function within a module, you need to clone the
function-local debug info and suppress cloning of global debug info (the
status quo suppresses cloning some global debug info but not all). When
cloning a function to a new/different module, you need to clone all of
the debug info.
Here's what I think we should do (eventually? soon? not this patch
though):
- Distinguish explicitly (somehow) between pure constant metadata owned
by the LLVMContext, global metadata owned by the Module, and local
metadata owned by a GlobalValue (such as a function).
- Update CloneFunctionInto to trigger cloning of all "local" metadata
(only), perhaps by adding a bit to RemapFlag. Alternatively, split
out a separate function CloneFunctionMetadataInto to prime the
metadata map that callers are updated to call ahead of time as
appropriate.
Here's the somewhat more isolated fix in this patch:
- Converted the `ModuleLevelChanges` parameter to `CloneFunctionInto` to
an enum called `CloneFunctionChangeType` that is one of
LocalChangesOnly, GlobalChanges, DifferentModule, and ClonedModule.
- The code maintaining the "functions uniquely own subprograms"
invariant is now only active in the first two cases, where a function
is being cloned within a single module. That's necessary because this
code inhibits cloning of (some) "global" metadata that's effectively
owned by the module.
- The code maintaining the "all compile units must be explicitly
referenced by !llvm.dbg.cu" invariant is now only active in the
DifferentModule case, where a function is being cloned into a new
module in isolation.
- CoroSplit.cpp's call to CloneFunctionInto in CoroCloner::create
uses LocalChangeOnly, since fa635d730f
only set `ModuleLevelChanges` to trigger cloning of local metadata.
- CloneModule drops its unsound use of RF_ReuseAndMutateDistinctMDs
and special handling of !llvm.dbg.cu.
- Fixed some outdated header docs and left a couple of FIXMEs.
Differential Revision: https://reviews.llvm.org/D96531
This allows for suspend point specific resume function types.
Return values from a suspend point can therefore be modelled as
arguments to the resume function. Allowing for directly passed return
types.
Differential Revision: https://reviews.llvm.org/D96136
Dynamic allocas that still exist have been verified to be only used
'locally' not accross a suspend point.
rdar://73903220
Differential Revision: https://reviews.llvm.org/D96071
and fix a few edge cases that show up in the Swift compiler but
weren't caught by the existing tests. Most notably the old code wasn't
salvaging load operations correctly. The patch also gets rid of the
LoadFromFramePtr argument and replaces it with a more generalized
mechanism.
This patch improves the availability for variables stored in the
coroutine frame by emitting an alloca to hold the pointer to the frame
object and rewriting dbg.declare intrinsics to point inside the frame
object using salvaged DIExpressions. Finally, a new alloca is created
in the funclet to hold the FramePtr pointer to ensure that it is
available throughout the entire function at -O0.
This path also effectively reverts D90772. The testcase updates
highlight nicely how every removed CHECK for a dbg.value is preceded
by a new CHECK for a dbg.declare.
Thanks to JunMa, Yifeng, and Bruno for their thoughtful reviews!
Differential Revision: https://reviews.llvm.org/D93497
rdar://71866936
Because we were not looking for the llvm.coro.id.async intrinsic in the
early coro pass which triggers follow-up passes we relied on the
llvm.coro.end intrinsic being present. This might not be the case in
functions that end in unreachable code.
Differential Revision: https://reviews.llvm.org/D95144
Summary: This is to address bug48712.
The solution in this patch is that when we want to merge two variable a
into the storage frame of variable b only if the alignment of a is
multiple of b.
There may be other strategies. But now I think they are hard to handle
and benefit little. Or we can implement them in the future.
Test-plan: check-llvm
Reviewers: jmorse, lxfind, junparser
Differential Revision: https://reviews.llvm.org/D94891
This is to address https://bugs.llvm.org/show_bug.cgi?id=48626.
When there are musttail calls that use parameters aliasing the newly created coroutine frame, the existing implementation will fatal.
We simply cannot perform CoroElide in such cases. In theory a precise analysis can be done to check whether the parameters of the musttail call
actually alias the frame, but it's very hard to do it before the transformation happens. Also in most cases the existence of musttail call is
generated due to symmetric transfers, and in those cases alias analysis won't be able to tell that they don't alias anyway.
Differential Revision: https://reviews.llvm.org/D94834
When building with GCC 10, the following warning is reported:
```
/llvm-project/llvm/lib/Transforms/Coroutines/CoroFrame.cpp:1527:28: warning: unused variable ‘CS’ [-Wunused-variable]
1527 | if (CatchSwitchInst *CS =
```
This change adds a cast to `void` to avoid the warning.
Reviewed By: lxfind
Differential Revision: https://reviews.llvm.org/D94456
promise is a header field but it is not guaranteed that it would be the third
field of the frame due to `performOptimizedStructLayout`.
Reviewed By: lxfind
Differential Revision: https://reviews.llvm.org/D94137
Apparently there can be no clones, as happens in
coro-retcon-unreachable.ll.
The alternative is to allow no split functions in
addSplitRefRecursiveFunctions(), but it seems better to have the caller
make sure it's not accidentally splitting no functions out.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D94258
Previously when trying to support CoroSplit's function splitting, we
added in a hack that simply added the new function's node into the
original function's SCC (https://reviews.llvm.org/D87798). This is
incorrect since it might be in its own SCC.
Now, more similar to the previous design, we have callers explicitly
notify the LazyCallGraph that a function has been split out from another
one.
In order to properly support CoroSplit, there are two ways functions can
be split out.
One is the normal expected "outlining" of one function into a new one.
The new function may only contain references to other functions that the
original did. The original function must reference the new function. The
new function may reference the original function, which can result in
the new function being in the same SCC as the original function. The
weird case is when the original function indirectly references the new
function, but the new function directly calls the original function,
resulting in the new SCC being a parent of the original function's SCC.
This form of function splitting works with CoroSplit's Switch ABI.
The second way of splitting is more specific to CoroSplit. CoroSplit's
Retcon and Async ABIs split the original function into multiple
functions that all reference each other and are referenced by the
original function. In order to keep the LazyCallGraph in a valid state,
all new functions must be processed together, else some nodes won't be
populated. To keep things simple, this only supports the case where all
new edges are ref edges, and every new function references every other
new function. There can be a reference back from any new function to the
original function, putting all functions in the same RefSCC.
This also adds asserts that all nodes in a (Ref)SCC can reach all other
nodes to prevent future incorrect hacks.
The original hacks in https://reviews.llvm.org/D87798 are no longer
necessary since all new functions should have been registered before
calling updateCGAndAnalysisManagerForPass.
This fixes all coroutine tests when opt's -enable-new-pm is true by
default. This also fixes PR48190, which was likely due to the previous
hack breaking SCC invariants.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D93828
Xun Li