This patch adds SIL-level debug info support for variables whose
static type is rewritten by an optimizer transformation. When a
function is (generic-)specialized or inlined, the static types of
inlined variables my change as they are remapped into the generic
environment of the inlined call site. With this patch all inlined
SILDebugScopes that point to functions with a generic signature are
recursively rewritten to point to clones of the original function with
new unique mangled names. The new mangled names consist of the old
mangled names plus the new substituions, similar (or exactly,
respectively) to how generic specialization is handled.
On libSwiftCore.dylib (x86_64), this yields a 17% increase in unique
source vars and a ~24% increase in variables with a debug location.
rdar://problem/28859432
rdar://problem/34526036
This patch adds SIL-level debug info support for variables whose
static type is rewritten by an optimizer transformation. When a
function is (generic-)specialized or inlined, the static types of
inlined variables my change as they are remapped into the generic
environment of the inlined call site. With this patch all inlined
SILDebugScopes that point to functions with a generic signature are
recursively rewritten to point to clones of the original function with
new unique mangled names. The new mangled names consist of the old
mangled names plus the new substituions, similar (or exactly,
respectively) to how generic specialization is handled.
On libSwiftCore.dylib (x86_64), this yields a 17% increase in unique
source vars and a ~24% increase in variables with a debug location.
rdar://problem/28859432
rdar://problem/34526036
Fixes <rdar://40555427> [SR-7773]:
SILCombiner::propagateConcreteTypeOfInitExistential fails to full propagate type
substitutions.
Fixes <rdar://problem/40923849>
SILCombiner::propagateConcreteTypeOfInitExistential crashes on protocol
compositions.
This rewrite fixes several fundamental bugs in the SILCombiner optimization that
propagates concrete types. In particular, the pass needs to handle:
- Arguments of callee Self type in non-self position.
- Indirect and direct return values of Self type.
- Types that indirectly depend on Self within callee function signature.
- Protocol composition existentials.
- All of the above need to work for protocol extensions as well as witness methods.
- For protocol extensions, conformance lookup should be based on the existential's conformance list.
Additionally, the optimization should not depend on a SILFunction's DeclContext,
which is not serialized. (In fact, we should prevent SIL passes from using
DeclContext). Furthermore, the code needs to be expressed in a way that one can
reason about correctness and invariants.
The root cause of these bugs is that SIL passes are written based on untested
assumptions of Swift type system. A SIL pass needs to handle all verifiable SIL
input because passes need to be composable. Bail-out logic can be added to
simplify the design; however, _the bail-out logic itself cannot make any
assumptions about the language or type system_ that aren't clearly and
explicitly enforced in the SIL verifier. This is a common mistake and major
source of bugs.
I created as many unit tests as I reasonably could to prevent this code from
regressing. Creating enough unit tests to cover all corner cases that were
broken in the original code would be intractable. But the code has been
simplified such that many corner cases disappear.
This opens up some oportunity for generalizing the optimization and eliminating
special cases. However, I want this PR to be limited to fixing correctness
issues only. In the long term, it would be preferable to replace this
optimization entirely with a much more powerful general type propagation pass.
SubstitutionMaps are now just a trivial pointer-sized value, so
pass them by value instead.
I did have to move a couple of functors from Type.h to SubstitutionMap.h
to resolve some issues with forward declarations.
There isn't a clean cut point here, so switch
GenericSpecializationInformation from SubstitutionList to
SubstitutionMap and carry along dual SubstitutionMap/SubstitutionList
representations for a small part of ReabstractionInfo.
This functionality is really specific to FunctionSignatureOpts. It really
doesn't make sense to have it as a utils until it becomes more general or we
need it in multiple places.
NFC.
rdar://38196046
I am getting rid of FunctionSignatureOptUtils. It is only used by
FunctionSignatureOpts, so it should either be a local utility file whose header
lives in ./lib or integrated into FunctionSignatureOpts. Beyond this utility
function (which seems like a generally useful thing that should be in
DebugUtils), the only other thing left in FunctionSignatureOptUtils is part of
the heuristic of FunctionSignatureOpts. It should really be in that file.
rdar://38196046
The devirtualizer performs two optimizations:
- If a value is known to have an exact class type, ie it is the result of an alloc_ref, we can devirtualize calls of *non-final* methods, because we know we’re calling that specific method and not an override.
- If a method is known to be “effectively final” (it is not open, and there are no overrides inside the module) we can devirtualize it.
However the second optimization needs to be disabled if a function is inlinable (F->getResilienceExpansion() == ResilienceExpansion::Minimal).
Create helpers in InstructionUtils.h wherever we need a guarantee that the diagnostics cover the same patterns as the verifier. Eventually this will be called from both SILVerifier and the diagnostic pass:
- findAccessedAddressBase
- isPossibleFormalAccessBase
- isPartialApplyOfReabstractionThunk
- findClosureForAppliedArg
- visitAccessedAddress
Add partial_apply verification assert.
This applies the normal "find a closure" logic inside the "find all partial_apply uses" verification. Making the verifier round-trip ensures that we don't have holes in exclusivity enforcement related to this logic.
We run GlobalOpt multiple times in the pass pipeline but in some cases object outlining shouldn't be done too early.
Having it done in a separate pass enables to run it independently from GlobalOpt.
We run GlobalOpt multiple times in the pass pipeline but in some cases object outlining shouldn't be done too early.
Having it done in a separate pass enables to run it independently from GlobalOpt.
Local.cpp was ~3k lines of which 1.5k (i.e. 1/2) was the cast optimizer. This
commit extracts the cast optimizer into its own .cpp and .h file. It is large
enough to stand on its own and allows for Local.cpp to return to being a small
group of helper functions.
I am making some changes in this area due to the change in certain function
conventions caused by the +0-normal-arg work. I am just trying to leave the area
a little cleaner than before.
Adds a combined API to output both debug message and optimization remarks.
The previously added test partial_specialization_debug.sil ensures that it's an
NFC for debug output.
Currently, the ownership verifier assumes that all cond_br with critical edges
do not have non-trivial arguments. This utility method fixes any such issues and
should be run /after/ any passes that mess with the CFG in ownership SIL if this
could come up.
Chopping this off of a larger commit.
rdar://31521023
This helper utility given a set of uses/defs determines the set of blocks that
together with the user blocks jointly post-dominate the def blocks. In a sense
this is completing the providing set of user blocks to a joint-post dominating
set. This completion is not unique.
I am adding this method because often times when working with Ownership SIL, one
needs to hoist/sink operations and then compensate to ensure that ownership
properties are still preserved.
I think with a little bit of work I can get the ownership model eliminator to
use this routine (since the condition for ownership to be correct on an @owned
value is an empty joint-post dominating completion. I wrote it b/c I need it in
pred-memopts and I expect it to be a general useful routine for Ownership SIL.
rdar://31521023
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.
This patch implements collection and dumping of statistics about SILModules, SILFunctions and memory consumption during the execution of SIL optimization pipelines.
The following statistics can be collected:
* For SILFunctions: the number of SIL basic blocks, the number of SIL instructions, the number of SIL instructions of a specific kind, duration of a pass
* For SILModules: the number of SIL basic blocks, the number of SIL instructions, the number of SIL instructions of a specific kind, the number of SILFunctions, the amount of memory used by the compiler, duration of a pass
By default, any collection of statistics is disabled to avoid affecting compile times.
One can enable the collection of statistics and dumping of these statistics for the whole SILModule and/or for SILFunctions.
To reduce the amount of produced data, one can set thresholds in such a way that changes in the statistics are only reported if the delta between the old and the new values are at least X%. The deltas are computed as using the following formula:
Delta = (NewValue - OldValue) / OldValue
Thresholds provide a simple way to perform a simple filtering of the collected statistics during the compilation. But if there is a need for a more complex analysis of collected data (e.g. aggregation by a pipeline stage or by the type of a transformation), it is often better to dump as much data as possible into a file using e.g. -sil-stats-dump-all -sil-stats-modules -sil-stats-functions and then e.g. use the helper scripts to store the collected data into a database and then perform complex queries on it. Many kinds of analysis can be then formulated pretty easily as SQL queries.
