Add core abstractions for identifying program entities across
compilation and link unit boundaries in the Scalable Static Analysis
Framework (SSAF).
Introduces three key components:
- BuildNamespace: Represents build artifacts (compilation units, link
units)
- EntityName: Globally unique entity identifiers across compilation
boundaries
- AST mapping: Functions to map Clang AST declarations to EntityNames
Entity identification uses Unified Symbol Resolution (USR) as the
underlying mechanism, with extensions for sub-entities (parameters,
return values) via suffixes. The abstraction allows whole-program
analysis by providing stable identifiers that persist across separately
compiled translation units.
