While I was using the new AccessUtils for a new optimization pass I discovered some areas for improvements. Also I found some bugs.
Changes:
* AccessBase: remove the unhealthy redundancy between `kind` and `baseAddress` types. Now AccessBase is single enum with the relevant base objects/addresses as payloads.
* AccessBase: for `global`, store the `GlobalValue` and not a `global_address` instruction, which is more accurate (because there can be multiple `global_addr`s for a single global variable)
* AccessBase: drop the support for function argument "pointers". The `pointer` is now always a `pointer_to_address` instruction. This also simplifies `PointerIdentification`: either it finds a matching `address_to_pointer` or it bails.
* AccessBase: improve `func isDistinct(from:)`. There are more possibilities to prove that two access bases do not alias.
* AccessBase: replace `var isUniquelyIdentified` with `var hasKnownStorageKind` which is more useful for aliasing checking.
* AccessPath: fix `func isDistinct(from:)`. `SmallProjectionPath.matches` is the wrong way to check if two expression paths may overlap. Instead use the new `SmallProjectionPath.mayOverlap`.
* AccessStoragePathWalker: rename `getAccessStorage` -> `visitAccessStorageRoots` and let it return false if it's not a class/reference AccessBase.
* add tests for `AccessPath.isDistinct(from:)`
It needs to return nil in case the callee argument is not really applied by the ApplySite.
This fixes a crash in EscapeInfo when handling "escaping-to" effects:
If the callee operand of an apply instruction is a `partial_apply` of a `function_ref`, the callee-analysis looks through the `partial_apply` and we get the referenced function as a callee.
In this case there are less apply arguments than callee arguments, because the `partial_apply` already "applies" some of the callee arguments.
rdar://96830171
This fixes a dangling pointer issue when creating a `Swift.String` from `std::string`.
Also fixes a warning:
```
warning: variable 's' was never mutated; consider changing to 'let' constant
var s = SILBasicBlock_debugDescription(bridged)
~~~ ^
let
```
rdar://92963081
rdar://93053488
* split the PassUtils.swift file into PassContext.swift and Passes.swift
* rework `Builder` bridging allowing more insertion point variations, e.g. inserting at the end of a block.
* add Builder.create functions for more instructions
* add `PassContext.splitBlock`
* move SIL modification functions from PassContext to extensions of the relevant types (e.g. instructions).
* rename `Location.bridgedLocation` -> `Location.bridged`
Reduces the number of _ContiguousArrayStorage metadata.
In order to support constant time bridging we do need to set the correct
metadata when we bridge to Objective-C. This is so that the type check
succeeds when bridging back from Objective-C to reuse the storage
instance rather than bridging the elements.
To support dynamically setting the `_ContiguousArrayStorage` element
type i needed to add support for optimizing `alloc_ref_dynamic`
throughout the optimizer.
Possible future improvements:
* Use different metadata such that we can disambiguate native Swift
classes during destruction -- allowing native release rather then unknown
release usage.
* Optimize the newly added semantic function
getContiguousArrayStorageType
rdar://86171143
Improve block/instruction lists and similar collections
* pretty print collections in the form “[a, b, c]”
* also do this for lazy sequences
* define a custom Mirror
* in a collection, only print the name of blocks, functions and globals (instead of the full object)
* replace `BasicBlock.reverseInstructions` with `BasicBlock.instructions.reversed()` - in an efficient way
Introduce a new instruction `dealloc_stack_ref ` and remove the `stack` flag from `dealloc_ref`.
The `dealloc_ref [stack]` was confusing, because all it does is to mark the deallocation of the stack space for a stack promoted object.
