To represent a type with code completion.
type? '.'? <code-completion-token>
This is "parser only" node which is not exposed to SwiftSyntax.
Using this, defer to set the parsed type to code-completion callbacks.
Instead of creating syntax nodes directly, modify the parser to invoke an abstract interface 'SyntaxParseActions' while it is parsing the source code.
This decouples the act of parsing from the act of forming a syntax tree representation.
'SyntaxTreeCreator' is an implementation of SyntaxParseActions that handles the logic of creating a syntax tree.
To enforce the layering separation of parsing and syntax tree creation, a static library swiftSyntaxParse is introduced to compose the two.
This decoupling is important for introducing a syntax parser library for SwiftSyntax to directly access parsing.
This allows an elegant design in which we can still allocate RawSyntax
nodes using a bump allocator but are able to automatically free that
buffer once the last RawSyntax node within that buffer is freed.
This also resolves a memory leak of RawSyntax nodes that was caused by
ParserUnit not freeing its underlying ASTContext.
Introduced SyntaxArena for managing memory and cache.
SyntaxArena holds BumpPtrAllocator as a allocation storage.
RawSyntax is now able to be constructed with normal heap allocation, or
by SyntaxArena. RawSyntax has ManualMemory flag which indicates it's managed by
SyntaxArena. If the flag is true, its Retain()/Release() is no-op thus it's
never destructed by IntrusiveRefCntPtr.
This speedups the memory allocation for RawSyntax.
Also, in Syntax parsing, "token" RawSyntax is reused if:
a) It's not string literal with >16 length; and
b) It doesn't contain random text trivia (e.g. comment).
This reduces the overall allocation cost.
To construct struct syntax, this patch first specialized type
inheritance clause. For protocol's class requirement, we currently
treat it as an unknown type.
This patch also teaches SyntaxParsingContext to collect syntax nodes
from back in place. This is useful to squash multiple decl modifiers
for declarations like function. This is not used for struct declaration
because only accessibility modifier is allowed.
* Generate libSyntax API
This patch removes the hand-rolled libSyntax API and replaces it with an
API that's entirely automatically generated. This means the API is
guaranteed to be internally stylistically and functionally consistent.
