add TODO list.
The Documentation directory contains a 'project ideas' document.
But some of the entries there are outdated, some are questionable
and some more are simply not clear about the problem or the goal.
Some important entries are also missing.
So, remove what's needed to be removed, reformulate unclear
entries and add a bunch of new things that should be done.
Also, rename the file to 'TODO.md' as this express more clearly
the intent of the document.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
diff --git a/Documentation/TODO.md b/Documentation/TODO.md
new file mode 100644
index 0000000..cbda1c3
--- /dev/null
+++ b/Documentation/TODO.md
@@ -0,0 +1,98 @@
+TODO
+====
+
+Essential
+---------
+* SSA is broken by simplify_loads() & branches rewriting/simplification
+* attributes of struct, union & enums are ignored (and possibly in other
+ cases too).
+* add support for bitwise enums
+
+Documentation
+-------------
+* document the extensions
+* document the API
+* document the limitations of modifying ptrlists during list walking
+* document the data structures
+* document flow of data / architecture / code structure
+
+Core
+----
+* if a variable has its address taken but in an unreachable BB then
+ its MOD_ADDRESSABLE may be wrong and it won't be SSA converted.
+ - let kill_insn() check killing of SYMADDR,
+ - add the sym into a list and
+ - recalculate the addressability before memops's SSA conversion
+* bool_ctype should be split into internal 1-bit / external 8-bit
+* Previous declarations and the definition need to be merged. For example,
+ in the code here below, the function definition is **not** static:
+ ```
+ static void foo(void);
+ void foo(void) { ... }
+ ```
+
+Testsuite
+--------
+* there are more than 50 failing tests. They should be fixed
+ (but most are non-trivial to fix).
+
+Misc
+----
+* GCC's -Wenum-compare / clangs's -Wenum-conversion -Wassign-enum
+* parse __attribute_((fallthrough))
+* add support for __builtin_unreachable()
+* add support for format(printf()) (WIP by Ben Dooks)
+* make use of UNDEFs (issues warnings, simplification, ... ?)
+* add a pass to inline small functions during simplification.
+
+Optimization
+------------
+* the current way of doing CSE uses a lot of time
+* add SSA based DCE
+* add SSA based PRE
+* Add SSA based SCCP
+* use better/more systematic use of internal verification framework
+
+IR
+--
+* OP_SET should return a bool, always
+* add IR instructions for va_arg() & friends
+* add a possibility to import of file in "IR assembly"
+* dump the symtable
+* dump the CFG
+
+LLVM
+----
+* fix ...
+
+Internal backends
+-----------------
+* add some basic register allocation
+* add a pass to transform 3-addresses code to 2-addresses
+* what can be done for x86?
+
+Longer term/to investigate
+--------------------------
+* better architecture handling than current machine.h + target.c
+* attributes are represented as ctypes's alignment, modifiers & contexts
+ but plenty of attributes doesn't fit, for example they need arguments.
+ * format(printf, ...),
+ * section("...")
+ * assume_aligned(alignment[, offsert])
+ * error("message"), warning("message")
+ * ...
+* should support "-Werror=..." ?
+* All warning messages should include the option how to disable it.
+ For example:
+ "warning: Variable length array is used."
+ should be something like:
+ "warning: Variable length array is used. (-Wno-vla)"
+* ptrlists must have elements be removed while being iterated but this
+ is hard to insure it is not done.
+* having 'struct symbol' used to represent symbols *and* types is
+ quite handy but it also creates lots of problems and complications
+* Possible mixup of symbol for a function designator being not a pointer?
+ This seems to make evaluation of function pointers much more complex
+ than needed.
+* extend test-inspect to inspect more AST fields.
+* extend test-inspect to inspect instructions.
diff --git a/Documentation/index.rst b/Documentation/index.rst
index 9825c8c..f8ca0dc 100644
--- a/Documentation/index.rst
+++ b/Documentation/index.rst
@@ -30,7 +30,7 @@
:maxdepth: 1
submitting-patches
- project-ideas
+ TODO
Indices and tables
==================
diff --git a/Documentation/project-ideas.md b/Documentation/project-ideas.md
deleted file mode 100644
index bff5f3d..0000000
--- a/Documentation/project-ideas.md
+++ /dev/null
@@ -1,51 +0,0 @@
-Why hacking on sparse
-=====================
-
-1. sparse is small.
- The full project compiles in less than 10 seconds on old and not performing laptop.
-2. sparse is fast.
- Typically, sparse can check a C file 1/10 of time it takes for gcc to generate object files.
-3. sparse can digest the full kernel source files.
- With sparse-llvm, sparse uses llvm as back end to emit real machine code.
-
-New developer hacking on sparse
-------------------------------
-
-* All sparse warning messages should include the option how
- to disable it.
- e.g. "pre-process.c:20*:28: warning: Variable length array is used."
- should be something like
- "pre-process.c:20*:28: warning: Variable length array is
-used. (-Wno-vla)"
-* extend test-inspect to inspect more AST fields.
-* extend test-inspect to inspect instructions.
-* adding architecture handling in sparse similar to cgcc
-* parallel processing of test-suite
-* Howto: fix the kernel rcu related checker warnings
-* option to disable AST level inline.
-* debug: debug version of sparse do all the verification double check
-* test suite: verify and compare IR (suggested by Dibyendu Majumdar)
-* checker error output database
-
-For experienced developers
---------------------------
-
-* merge C type on incremental declare of C type and function prototype.
-* move attribute out of ctype to allow easier to add new attribute.
-* serialize, general object walking driven by data structures.
-* serialize, write sparse byte code into file
-* serialize, load sparse byte code from file.
-* symbol index/linker, know which symbol in which byte code file.
-* inline function in instruction level
-* cross function checking
-* debug: optimization step by step log
-* debug: fancy animation of CFG
-* phi node location (Luc has patch)
-* revisit crazy programmer warning, invalid SSA form.
-* ptrlist, looping while modify inside the loop.
-* dead code elimination using ssa
-* constant propagation using ssa.
-* x86/arm back end instruction set define
-* register allocation.
-* emit x86/arm machine level code
-
