I thought I would chime in with some ideas and opinions:
o Configuration Files
If it isn't too much trouble, I think we should go with XML for the following reasons:
1) We wouldn't need to implement a parsing library. There are several XML parsing libraries available, and I'm guessing that they're available in several different programming languages (Reid, am I right on that?).
2) It makes it easier for other programmers to write tools that read, modify, and/or write the configuration file correctly. If my assumption about XML libraries being available in several different languages is correct, then that means we don't need to write a library for each language that people want to use.
3) I believe it would keep the format flexibile enough for future expansion (but again, Reid would know better here).
Having configuration files that can be manipulated accurately is important for things like automatic installation, GUI's, configuration tools, etc.
o Object Files
I've noticed that there's a general agreement that we should not encapsulate LLVM bytecode files inside of another object format (such as ELF). However, I'd like to pose a few potential benefits that encapsulation in ELF might provide:
1) It may provide a way for standard UNIX tools to handle bytecode files without modification. For example, programs like ar, nm, and file all take advantage of the ELF format. If we generated LLVM ELF files, we wouldn't need to write our own nm and ar implementations and port them to various platforms.
2) It could mark the bytecode file with other bits of useful information, such as the OS and hardware on which the file was generated.
3) It may provide a convenient means of adding dynamic linking with other bytecode files.
4) It may provide a convenient place to cache native translations for use with the JIT.
Here are the disadvantages I see:
1) Increased disk usage. For example, symbol table information would duplicate the information already in the bytecode file.
2) Automatic execution. Ideally, if I have a bytecode executable, I want to run it directly. On UNIX, that is done with #!<interpreter>. I believe ELF provides similar functionality (where exec()ing the file can load a program or library to do JIT compilation), but if it doesn't, then we lose this feature.
o Compiler Driver Name
I'd vote for either llvmcc (llvm compiler collection) or llvmcd (llvm compiler driver). To be more convenient, we could call it llc (LLvm Compiler) or llcd (LLvm Compiler Driver). Calling it llc would require renaming llc to something else, which might be appropriate since I view llc as a "code generator" and not as a "compiler" (although both terms are technically accurate).
Generally, I recommend keeping the name short and not using hyphens (because it's slower to type them).
o Optimization options
I agree with the idea of using -O<number> for increasing levels of optimization, with -O0 meaning no optimization. It's a pretty intuitive scheme, and many Makefiles that use GCC use the -O option.
-- John T.