Add a wish list of projects. (#27)

Create a list of projects that people could work on now or soon (in
the next few months).

WishList.md

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+# A Wish List of Checked C Projects.
+
+There is plenty of work to do on Checked C. Here is a list of projects 
+that could be begun now or in the next few months.  The projects cover compiler
+implementation, tools, language design, and experimental evaluation.  The 
+projects range in nature from implementation to design to open research
+problems.  If you decide to work on a project, it would be helpful to let us
+know so that we can try to coordinate work among interested parties.
+
+# Compiler implementation
+
+Here are projects for the LLVM/clang implementation of Checked C.  Some 
+projects could be begun now.  Others will need to wait until bounds declarations
+are added to the clang AST.
+
+- Nightly build automation and build testing.
+- Pointer arithmetic for checked pointers types that has overflow checking.
+- Non-null checks for checked pointer types.
+- Span pointer types: parsing, representation in IR, typechecking, and
+  implementation of operations.
+- Insert runtime bounds checks during the lowering to LLVM IR.
+- Enforce the rule in Section 3.2 that all uses of externally-scoped variables
+  within a compilation unit have the same view of the bounds for the variable.
+-  Bounds-safe interfaces for functions and static variables:
+-- Parsing of interoperation annotations for unchecked pointer types.
+-- Insertion of implicit type coercions between checked and unchecked pointer
+   types.
+-- Compatibility between declarations with and without bounds information.
+-- Checks that there are no intervening definitions.
+-  Checked/unchecked blocks.
+- Bounds declarations for structure types and structure member operations.
+
+Another interesting direction is to begin implementing Checked C in other
+compilers such as GCC.
+
+# Tools
+
+- Create tools that modify existing C code to use features in Checked C. One possible project 
+  is to build a tool that identifies pointers that are never used with pointer arithmetic
+  and convert them to _ptr_.  We have implemented typechecking for the _ptr_ type in LLVM/clang,
+  so the typechecking rules for _ptr_ would be enforced.
+
+# Experimental evaluation
+
+- Try applying Checked C to additional code bases.  We are experimenting with OpenSSL.
+  It would be useful to gather experiences with other code bases, which will have
+  different coding styles and address other problem domains.  
+
+# Language design
+
+- Extend the Checked C design to describe null-terminated array types.
+- Extend the C language definition notion of compatibility to declarations
+  with and without bounds information. This would allow bounds-safe
+  interfaces to be declared for C standard library functions, without 
+  modifying the source code for existing headers.
+- Add a way to describe that aliasing (or anti-aliasing) properties of data
+  structures.  This would allow bounds invariants to be suspended for certain
+  data during function calls.
+- Ways to check the correct use of the following memory management strategies
+  used in C programs:
+-- Stack allocation.
+-- Reference counting
+-- Regions.
+- A design for checking the correctness of explicit memory management
+strategies.
+
+
+
+
+
+