Use MemoryLayout.stride instead pf MemoryLayout.size. This fixes a buffer overflow bug in case of unaligned elements.
Plus some other bug fixes for stacklists which get larger than a single slab.
Also, add the `append(contentsOf:)` method.
* unify FunctionPassContext and InstructionPassContext
* add a modification API: PassContext.setOperand
* automatic invalidation notifications when the SIL is modified
Instruction passes are basically visit functions in SILCombine for a specific instruction type.
With the macro SWIFT_INSTRUCTION_PASS such a pass can be declared in Passes.def.
SILCombine then calls the run function of the pass in libswift.
StackList is a very efficient data structure for worklist type things.
This is a port of the C++ utility with the same name.
Compared to Array, it does not require any memory allocations.
With the macro SWIFT_FUNCTION_PASS a new libswift function pass can be defined in Passes.def.
The SWIFT_FUNCTION_PASS_WITH_LEGACY is similar, but it allows to keep an original C++ “legacy” implementation of the pass, which is used if the compiler is not built with libswift.
It's not needed anymore with delayed instruction deletion.
It was used for two purposes:
1. For analysis, which cache instructions, to avoid dangling instruction pointers
2. For passes, which maintain worklists of instructions, to remove a deleted instructions from the worklist. This is now done by checking SILInstruction::isDeleted().
When an instruction is "deleted" from the SIL, it is put into the SILModule::scheduledForDeletion list.
The instructions in this list are eventually deleted for real in SILModule::flushDeletedInsts(), which is called by the pass manager after each pass run.
In other words: instruction deletion is deferred to the end of a pass.
This avoids dangling instruction pointers within the run of a pass and in analysis caches.
Note that the analysis invalidation mechanism ensures that analysis caches are invalidated before flushDeletedInsts().
* rename -sil-print-only-function to -sil-print-function and -sil-print-only-functions to -sil-print-functions
* to print single functions, don't require -Xllvm -sil-print-all. It's now sufficient to use e.g. -Xllvm -sil-print-function=<f>
But it's still possible to select functions with -sil-print-function(s) for other print options, -sil-print-after.
This removes the ambiguity when casting from a SingleValueInstruction to SILNode, which makes the code simpler. E.g. the "isRepresentativeSILNode" logic is not needed anymore.
Also, it reduces the size of the most used instruction class - SingleValueInstruction - by one pointer.
Conceptually, SILInstruction is still a SILNode. But implementation-wise SILNode is not a base class of SILInstruction anymore.
Only the two sub-classes of SILInstruction - SingleValueInstruction and NonSingleValueInstruction - inherit from SILNode. SingleValueInstruction's SILNode is embedded into a ValueBase and its relative offset in the class is the same as in NonSingleValueInstruction (see SILNodeOffsetChecker).
This makes it possible to cast from a SILInstruction to a SILNode without knowing which SILInstruction sub-class it is.
Casting to SILNode cannot be done implicitly, but only with an LLVM `cast` or with SILInstruction::asSILNode(). But this is a rare case anyway.
This removes the ambiguity when casting from a SingleValueInstruction to SILNode, which makes the code simpler. E.g. the "isRepresentativeSILNode" logic is not needed anymore.
Also, it reduces the size of the most used instruction class - SingleValueInstruction - by one pointer.
Conceptually, SILInstruction is still a SILNode. But implementation-wise SILNode is not a base class of SILInstruction anymore.
Only the two sub-classes of SILInstruction - SingleValueInstruction and NonSingleValueInstruction - inherit from SILNode. SingleValueInstruction's SILNode is embedded into a ValueBase and its relative offset in the class is the same as in NonSingleValueInstruction (see SILNodeOffsetChecker).
This makes it possible to cast from a SILInstruction to a SILNode without knowing which SILInstruction sub-class it is.
Casting to SILNode cannot be done implicitly, but only with an LLVM `cast` or with SILInstruction::asSILNode(). But this is a rare case anyway.
The PassManager should transform all functions in bottom up order.
This is necessary because when optimizations like inlining looks at the
callee function bodies to compute profitability, the callee functions
should have already undergone optimizations to get better profitability
estimates.
The PassManager builds its function worklist based on bottom up order
on initialization. However, newly created SILFunctions due to
specialization etc, are simply appended to the function worklist. This
can cause us to make bad inlining decisions due to inaccurate
profitability estimates. This change now updates the function worklist such
that, all the callees of the newly added SILFunction are proccessed
before it by the PassManager.
Fixes rdar://52202680
* Fix the mid-level pass pipeline.
Module passes need to be in a separate pipeline, otherwise the
pipeline restart mechanism will be broken.
This makes GlobalOpt and serialization run earlier in the
pipeline. There's no explicit reason for them to be run later, in the
middle of a function pass pipeline.
Also, pipeline boundaries, like serialization and module passes should
be explicit at the the top level function that creates the pass
pipelines.
* SILOptimizer: Add enforcement of function-pass pipelines.
Don't allow module passes to be inserted within a function pass
pipeline. This silently breaks the function pipeline both interfering
with analysis and the normal pipeline restart mechanism.
* Add misssing pass in addFunctionPasses
Co-authored-by: Andrew Trick <atrick@apple.com>
-sil-verify-all flag will verify analyses before and after a pass to
confirm correct invalidations. But if an analysis was never
constructed or invalidated as per current pass order,
it may never detect insufficient invalidations.
-sil-verify-force-analysis will force construct an analysis so that we
can better check for insufficient invalidations.
It is also terribly slow compared to -sil-verify-all.
A request is intended to be a pure function of its inputs. That function could, in theory, fail. In practice, there were basically no requests taking advantage of this ability - the few that were using it to explicitly detect cycles can just return reasonable defaults instead of forwarding the error on up the stack.
This is because cycles are checked by *the Evaluator*, and are unwound by the Evaluator.
Therefore, restore the idea that the evaluate functions are themselves pure, but keep the idea that *evaluation* of those requests may fail. This model enables the best of both worlds: we not only keep the evaluator flexible enough to handle future use cases like cancellation and diagnostic invalidation, but also request-based dependencies using the values computed at the evaluation points. These aforementioned use cases would use the llvm::Expected interface and the regular evaluation-point interface respectively.
Introduce evaluator::SideEffect, the type of a request that performs
some operation solely to execute its side effects. Thankfully, there are
precious few requests that need to use this type in practice, but it's
good to call them out explicitly so we can get around to making them
behave much more functionally in the future.
Add ExecuteSILPipelineRequest which executes a
pipeline plan on a given SIL (and possibly IRGen)
module. This serves as a top-level request for
the SILOptimizer that we'll be able to hang
dependencies off.
Rather than registering individual IRGen passes
when we want to execute them, store function
pointers to all the pass constructors on the
ASTContext. This will make it easier to requestify
the execution of pass pipelines.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
I believe that these were in SILInstruction for historic reasons. This is a
separate API on top of SILInstruction so it makes sense to pull it out into its
own header.
This helps speed up triaging failures caught by -sil-verify-all since this
allows one to trigger the -sil-verify-all verification around specific passes in
the pipeline rather than after every pass run. Was useful for me when tracking
down missing pass manager notification.
This is a verification routine that is only invoked in PassManager
destructors. I am going to use this to ensure that the
PassManagerVerifierAnalysis only runs at such points (even when sil-verify-all
is enabled) since it is too expensive to run otherwise.
NOTE: The default implementation of verifyFull in this commit is a no-op. I
wanted to have verify() be the default implementation of verifyFull(), but I do
not have more time to invest in this and it seems to catch /real/ bugs, albeit
bugs unrelated to pass manager notification verification. Instead I am going to
file an SR for someone to look at it since I need to move on from this work back
to semantic SIL. At least we will not have notification failure issues anymore
and thus a large correctness issue in the compiler has been fixed. Forward
progress!
rdar://42301529
* rename "Name" to "Description" in the pass definition, because it's not really the pass name, but the description of a pass
* remove the getName() from Transforms (which actually returned the description of a pass)
* in debug printing, print the pass ID and not the pass description. It makes it easier to correlate the debug output to the actual pass implementation.
* remove the iteration numbering in the pass manager, because we only run a single iteration anyway.
This commit is mostly refactoring.
*) Introduce a new OptimizationMode enum and use that in SILOptions and IRGenOptions
*) Allow the optimization mode also be specified for specific SILFunctions. This is not used in this commit yet and thus still a NFC.
Also, fixes a minor bug: we didn’t run mandatory IRGen passes for functions with @_semantics("optimize.sil.never")
In the crash output 'While running pass #x SILFunctionTransform "T" on SILFunction "@F".' we printed the previous function which was handled by the pass instead of the current one.
introduce a common superclass, SILNode.
This is in preparation for allowing instructions to have multiple
results. It is also a somewhat more elegant representation for
instructions that have zero results. Instructions that are known
to have exactly one result inherit from a class, SingleValueInstruction,
that subclasses both ValueBase and SILInstruction. Some care must be
taken when working with SILNode pointers and testing for equality;
please see the comment on SILNode for more information.
A number of SIL passes needed to be updated in order to handle this
new distinction between SIL values and SIL instructions.
Note that the SIL parser is now stricter about not trying to assign
a result value from an instruction (like 'return' or 'strong_retain')
that does not produce any.
