This patch overhauls the "memory region" abstraction that was prototyped (but never really used) as part of the Store.h. This patch adds MemRegion.h and MemRegion.cpp, which defines the class MemRegion and its subclasses. This classes serve to define an abstract representation of memory, with regions being layered on other regions to to capture the relationships between fields and variables, variables and the address space they are allocated in, and so on.
The main motivation of this patch is that key parts of the analyzer assumed that all value bindings were to VarDecls. In the future this won't be the case, and this patch removes lval::DeclVal and replaces it with lval::MemRegionVal. Now all pieces of the analyzer must reason about abstract memory blocks instead of just variables.
There should be no functionality change from this patch, but it opens the door for significant improvements to the analyzer such as field-sensitivity and object-sensitivity, both which were on hold until the memory abstraction got generalized.
The memory region abstraction also allows type-information to literally be affixed to a memory region. This will allow the some now redundant logic to be removed from the retain/release checker.
llvm-svn: 57042
Constraints. These concepts are already present in the current ValueState, but
the implementation is monolothic. Making ValueState more modular opens up new
design choices for customizing the analysis engine.
In the context of the analysis engine, the "Environment" is the binding between
Expr* (expressions) and intermediate symbolic values (RValues).
llvm-svn: 53252
Zhongxing Xu