- Always use a fast function to replace a slow one if available
- Iterate to fixed point (i.e.: if combining made more functions
identical, combine those too). This will be more useful in the future.
- Use only single, const traversal
Introduce VNRef that can be used to wrap AstNode keys in STL
collections, resulting in equality comparisons rather than identity
comparisons. This can then replace the SenTreeSet data-structure.
What previously used to be per module static constants created in
V3Table and V3Prelim are now merged globally within the whole model and
emitted as part of a separate constant pool. Members of the constant
pool are global variables which are declared lazily when used (similar to
loose methods).
This patch introduces the concept of 'loose' methods, which semantically
are methods, but are declared as global functions, and are passed an
explicit 'self' pointer. This enables these methods to be declared
outside the class, only when they are needed, therefore removing the
header dependency. The bulk of the emitted model implementation now uses
loose methods.
Rework Ast hashing to be stable
Eliminated reliance on pointer values in AstNode hashes in order to make
them stable. This requires moving the sameHash functions into a visitor,
as nodes pointed to via members (and not child nodes) need to be hashed
themselves.
The hashes are now stable (as far as I could test them), and the impact
on verilation time is small enough not to be reliably measurable.
V3Hasher is responsible for computing AstNode hashes, while V3DupFinder
can be used to find duplicate trees based on hashes. Interface of
V3DupFinder simplified somewhat. No functional change intended at this
point, but hash computation might differ in minor details, this however
should have no perceivable effect on output/runtime.
Implements (#2964)
Geza Lore
Wilson Snyder