Random standard-conforming known things that should be added to pcc:

• Currently all known usable C99 stuff is added.

Internal cleanups:

• Cleanup prototype parsing and checking.

• Ensure that the instruction matcher do not assume that it will reclaim a register if a direct match of something else than a register is done as a leg node. This may require additions to visit and su fields in table and node.

• Teach the register allocator how to allocate multiple registers at once. This is not the same as register pairs; pairing is handled as a separate register class. This is used for example when a type is not supported by the underlying hardware, like long long on i386 or long on pdp11.

GCC compatibility:

• PCC has GCC compatibility enabled by default, but there are a number of language constructs that may not be fully implemented, like attributes.

• There's similar work needed in the C preprocessor area. #pragmas are the first thing that comes to mind.

Portability:

• The i386 and amd64 are now stable enough to build most C programs, including PCC itself. More work is needed to make it available in other platforms, especially MIPS and ARM.

• Testing PCC in more recent versions of supported operating systems, especially the BSD flavors.