The semantic nodes cannot be fully immutable, as they contain cyclic
references. Remove Resolver::CreateSemanticNodes(), and instead
construct and mutate the semantic nodes in the single traversal pass.
Give up on trying to maintain the 'authored' type names (aliased names).
These are a nightmare to maintain, and provided limited use.
Significantly simplfies the Resolver, and allows us to generate more
semantic to semantic references, reducing sem -> ast -> sem hops.
Note: This change introduces constant value propagation across constant
variables. This is unlocked by the earlier construction of the
sem::Variable.
Change-Id: I592092fdc47fe24d30e512952511c9ab7c16d7a1
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/68406
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>
This change introduces sem::CompoundStatement, a new base class for
statements that can hold other statements.
sem::BlockStatements now derives from sem::CompoundStatement, and
this change introduces the following new CompoundStatements:
* `sem::IfStatement`
* `sem::ElseStatement`
* `sem::ForLoopStatement`
* `sem::LoopStatement`
* `sem::SwitchStatement`.
These new CompoundStatements are now inserted into the semantic
tree as now documented in `docs/compound_statements.md`.
The `sem::BlockStatement::FindFirstParent()` methods have been
moved down to `sem::Statement`.
The `Resolver::BlockScope()` method has been replaced with
`Resolver::Scope()` which now maintains the `current_statement_`,
`current_compound_statement_ ` and `current_block_`. This
simplifies statement nesting.
The most significant change in behavior is that statements now
always have a parent, so calling Block() on the initializer or
continuing of a for-loop statement will now return the
BlockStatement that holds the for-loop. Before this would
return nullptr.
Fixed: tint:979
Change-Id: I90e38fd719da2a281ed9210e975ab96171cb6842
Reviewed-on: https://dawn-review.googlesource.com/c/tint/+/57707
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Ben Clayton <bclayton@google.com>
Reviewed-by: James Price <jrprice@google.com>
