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.