* Reduce array abstraction on apple platforms dealing with literals
Part of the ongoing quest to reduce swift array literal abstraction
penalties: make the SIL optimizer able to eliminate bridging overhead
when dealing with array literals.
Introduce a new classify_bridge_object SIL instruction to handle the
logic of extracting platform specific bits from a Builtin.BridgeObject
value that indicate whether it contains a ObjC tagged pointer object,
or a normal ObjC object. This allows the SIL optimizer to eliminate
these, which allows constant folding a ton of code. On the example
added to test/SILOptimizer/static_arrays.swift, this results in 4x
less SIL code, and also leads to a lot more commonality between linux
and apple platform codegen when passing an array literal.
This also introduces a couple of SIL combines for patterns that occur
in the array literal passing case.
This replaces the '[volatile]' flag. Now, class_method and
super_method are only used for vtable dispatch.
The witness_method instruction is still overloaded for use
with both ObjC protocol requirements and Swift protocol
requirements; the next step is to make it only mean the
latter, also using objc_method for ObjC protocol calls.
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.
Till now createApply, createTryApply, createPartialApply were taking some arguments like SubstCalleeType or ResultType. But these arguments are redundant and can be easily derived from other arguments of these functions. There is no need to put the burden of their computation on the clients of these APIs.
The removal of these redundant parameters simplifies the APIs and reduces the possibility of providing mismatched types by clients, which often happened in the past.
At some point, pass definitions were heavily macro-ized. Pass
descriptive names were added in two places. This is not only redundant
but a source of confusion. You could waste a lot of time grepping for
the wrong string. I removed all the getName() overrides which, at
around 90 passes, was a fairly significant amount of code bloat.
Any pass that we want to be able to invoke by name from a tool
(sil-opt) or pipeline plan *should* have unique type name, enum value,
commend-line string, and name string. I removed a comment about the
various inliner passes that contradicted that.
Side note: We should be consistent with the policy that a pass is
identified by its type. We have a couple passes, LICM and CSE, which
currently violate that convention.
A new SubstitutionMap::getProtocolSubstitutions() method handles
the case where we construct a trivial SubstitutionMap to replace
the protocol Self type with a concrete type.
When substituting one opened existential archetype for another,
use the form of Type::subst() that takes two callbacks instead of
building a SubstitutionMap. SubstitutionMaps are intended to be
used with keys that either come from a GenericSignature or a
GenericEnvironment, so using them to replace opened archetypes
doesn't fit the conceptual model we're going for.
Separate formal lowered types from SIL types.
The SIL type of an argument will depend on the SIL module's conventions.
The module conventions are determined by the SIL stage and LangOpts.
Almost NFC, but specialized manglings are broken incidentally as a result of
fixes to the way passes handle book-keeping of aruments. The mangler is fixed in
the subsequent commit.
Otherwise, NFC is intended, but quite possible do to rewriting the logic in many
places.
Not sure why but this was another "toxic utility method".
Most of the usages fell into one of three categories:
- The base value was always non-null, so we could just call
getCanonicalType() instead, making intent more explicit
- The result was being compared for equality, so we could
skip canonicalization and call isEqual() instead, removing
some boilerplate
- Utterly insane code that made no sense
There were only a couple of legitimate uses, and even there
open-coding the conditional null check made the code clearer.
Also while I'm at it, make the SIL open archetypes tracker
more typesafe by passing around ArchetypeType * instead of
Type and CanType.
We preserve the current behavior of assuming Any ownership always and use
default arguments to hide this change most of the time. There are asserts now in
the SILBasicBlock::{create,replace,insert}{PHI,Function}Argument to ensure that
the people can only create SILFunctionArguments in entry blocks and
SILPHIArguments in non-entry blocks. This will ensure that the code in tree
maintains the API distinction even if we are not using the full distinction in
between the two.
Once the verifier is finished being upstreamed, I am going to audit the
createPHIArgument cases for the proper ownership. This is b/c I will be able to
use the verifier to properly debug the code. At that point, I will also start
serializing/printing/parsing the ownershipkind of SILPHIArguments, but lets take
things one step at a time and move incrementally.
In the process, I also discovered a CSE bug. I am not sure how it ever worked.
Basically we replace an argument with a new argument type but return the uses of
the old argument to refer to the old argument instead of a new argument.
rdar://29671437
For a long time, we have:
1. Created methods on SILArgument that only work on either function arguments or
block arguments.
2. Created code paths in the compiler that only allow for "function"
SILArguments or "block" SILArguments.
This commit refactors SILArgument into two subclasses, SILPHIArgument and
SILFunctionArgument, separates the function and block APIs onto the subclasses
(leaving the common APIs on SILArgument). It also goes through and changes all
places in the compiler that conditionalize on one of the forms of SILArgument to
just use the relevant subclass. This is made easier by the relevant APIs not
being on SILArgument anymore. If you take a quick look through you will see that
the API now expresses a lot more of its intention.
The reason why I am performing this refactoring now is that SILFunctionArguments
have a ValueOwnershipKind defined by the given function's signature. On the
other hand, SILBlockArguments have a stored ValueOwnershipKind. Rather than
store ValueOwnershipKind in both instances and in the function case have a dead
variable, I decided to just bite the bullet and fix this.
rdar://29671437
Changes:
* Terminate all namespaces with the correct closing comment.
* Make sure argument names in comments match the corresponding parameter name.
* Remove redundant get() calls on smart pointers.
* Prefer using "override" or "final" instead of "virtual". Remove "virtual" where appropriate.
This simplifies the SILType substitution APIs and brings them in line with Doug and Slava's refactorings to improve AST-level type substitution. NFC intended.
Before this commit all code relating to handling arguments in SILBasicBlock had
somewhere in the name BB. This is redundant given that the class's name is
already SILBasicBlock. This commit drops those names.
Some examples:
getBBArg() => getArgument()
BBArgList => ArgumentList
bbarg_begin() => args_begin()
Type substitution works on a fairly narrow set of types: generic type
parameters (to, e.g., use a generic) and archetypes (to map out of a
generic context). Historically, it was also used with
DependentMemberTypes, but recent refactoring to eliminate witness
markers eliminate that code path.
Therefore, narrow TypeSubstitutionMap's keys to SubstitutableType,
which covers archetypes and generic type parameters. NFC
The new instructions are: ref_tail_addr, tail_addr and a new attribute [ tail_elems ] for alloc_ref.
For details see docs/SIL.rst
As these new instructions are not generated so far, this is a NFC.
The new instructions are: ref_tail_addr, tail_addr and a new attribute [ tail_elems ] for alloc_ref.
For details see docs/SIL.rst
As these new instructions are not generated so far, this is a NFC.
When performing a CSE of open_existential_ref instructions, we replace the new archetype by the old archetype by cloning the uses and re-mapping the archetypes. But we also need to consider that some of the uses of a open_existential_ref instruction (e.g. loads) may produce results depending on the opened archetype being replaced. Therefore, for every such use its own uses (and their uses) should be eventually recursively cloned and type-remapped as well if they depend on the opened archetype being replaced.
Fixes rdar://28136015 and https://bugs.swift.org/browse/SR-2545
This establishes a real def-use relation from the self-parameter to any instruction which uses the dynamic-self type.
This is an addition to what was already done for opened archetypes.
The biggest part of this commit is to rename "OpenedArchetypeOperands" to "TypeDependentOperands" as this name is now more appropriate.
Other than that the change includes:
*) type-dependent operands are now printed after a SIL instruction in a comment as "type-defs:" (for debugging)
*) FuncationSignatureOpts doesn't need to explicitly check if a function doesn't bind dynamic self to remove a dead self metadata argument
*) the check if a function binds dynamic self (used in the inliner) is much simpler now
*) also collect type-dependent operands for ApplyInstBase::SubstCalleeType and not only in the substitution list
*) with this SILInstruction::mayHaveOpenedArchetypeOperands (used in CSE) is not needed anymore and removed
*) add type dependent operands to dynamic_method instruction
Regarding the generated code it should be a NFC.
Opened archetypes may be used by types of basic block arguments. Therefore, when performing the CSE of open_existential_ref instructions, one should also update the type of any basic block argument that may have used the archetype opened by the open_existential_ref being replaced.
rdar://problem/27386065
Strict aliasing only applies to memory operations that use strict
addresses. The optimizer needs to be aware of this flag. Uses of raw
addresses should not have their address substituted with a strict
address.
Also add Builtin.LoadRaw which will be used by raw pointer loads.
This enables things like redundant load elimination and should fix the
regression after changing ManagedBuffer(Pointer) to use unsafeAddressWithOwner.
rdar://27138023
Till now there was no way in SIL to explicitly express a dependency of an instruction on any opened archetypes used by it. This was a cause of many errors and correctness issues. In many cases the code was moved around without taking into account these dependencies, which resulted in breaking the invariant that any uses of an opened archetype should be dominated by the definition of this archetype.
This patch does the following:
- Map opened archetypes to the instructions defining them, i.e. to open_existential instructions.
- Introduce a helper class SILOpenedArchetypesTracker for creating and maintaining such mappings.
- Introduce a helper class SILOpenedArchetypesState for providing a read-only API for looking up available opened archetypes.
- Each SIL instruction which uses an opened archetype as a type gets an additional opened archetype operand representing a dependency of the instruction on this archetype. These opened archetypes operands are an in-memory representation. They are not serialized. Instead, they are re-constructed when reading binary or textual SIL files.
- SILVerifier was extended to conduct more thorough checks related to the usage of opened archetypes.
Till now there was no way in SIL to explicitly express a dependency of an instruction on any opened archetypes used by it. This was a cause of many errors and correctness issues. In many cases the code was moved around without taking into account these dependencies, which resulted in breaking the invariant that any uses of an opened archetype should be dominated by the definition of this archetype.
This patch does the following:
- Map opened archetypes to the instructions defining them, i.e. to open_existential instructions.
- Introduce a helper class SILOpenedArchetypesTracker for creating and maintaining such mappings.
- Introduce a helper class SILOpenedArchetypesState for providing a read-only API for looking up available opened archetypes.
- Each SIL instruction which uses an opened archetype as a type gets an additional opened archetype operand representing a dependency of the instruction on this archetype. These opened archetypes operands are an in-memory representation. They are not serialized. Instead, they are re-constructed when reading binary or textual SIL files.
- SILVerifier was extended to conduct more thorough checks related to the usage of opened archetypes.
Till now there was no way in SIL to explicitly express a dependency of an instruction on any opened archetypes used by it. This was a cause of many errors and correctness issues. In many cases the code was moved around without taking into account these dependencies, which resulted in breaking the invariant that any uses of an opened archetype should be dominated by the definition of this archetype.
This patch does the following:
- Map opened archetypes to the instructions defining them, i.e. to open_existential instructions.
- Introduce a helper class SILOpenedArchetypesTracker for creating and maintaining such mappings.
- Introduce a helper class SILOpenedArchetypesState for providing a read-only API for looking up available opened archetypes.
- Each SIL instruction which uses an opened archetype as a type gets an additional opened archetype operand representing a dependency of the instruction on this archetype. These opened archetypes operands are an in-memory representation. They are not serialized. Instead, they are re-constructed when reading binary or textual SIL files.
- SILVerifier was extended to conduct more thorough checks related to the usage of opened archetypes.
It is a hint to the optimizer that the code, where this builtin is called, is on the fast path.
Specifically, the inliner takes it into account and increases the assumed benefit for code where the builtin is located.
Compared to the fastPath/slowPath builtins, this builtin can be placed into plain linear code and doesn't need to be used in conditions.
Compared to the @inline(__always) attribute, this builtin has also an effect on the caller function. Let's assume
foo() calls bar() contains onFastPath
and both foo and bar are small functions. Then if bar gets inlined into foo, the builtin also increases the chances that foo gets inlined.
This would not be the case if @inline(__always) is used just for bar.
When we emit calls to existential methods silgen produces a sequence of the
three instructions below:
open_existential_addr %0 : $*Pingable to $*@opened("1E467EB8-...") Pingable
witness_method $@opened("1E467EB8-...") Pingable, #Pingable.ping!1
apply %3<@opened("1E467EB8-...") Pingable>(%2)
This commit adds a new CSE-like pass that finds sequences of calls to protocol
methods and reuses the first two instructions open_existential_addr and
witness_method. The optimization finds arguments that must not alias and may not
escape and combines all of the existential method calls to use the same method
lookup. The optimization handles control flow by finding the top dominating
open_existential instruction, and uses that instruction.
related to rdar://22704464.
