Devon H. O'Dell wrote: > Another student I spoke to on IRC spoke of the possibility of > bootstrapping LLVM for Plan 9 on Linux and getting it to run natively. > That would give us a whole bunch of different compilers.
Something to watch out for with such a project: The LLVM back-end for Windows does not support C++ (nicely) because of issues with exception handling; Windows provides a mechanism for stack unwinding—especially across DLL boundaries—that neither GCC nor LLVM handle well. Porting LLVM to Plan 9 may well have some of the same troubles. Those who have dealt with the GCC port can answer this: What does g++ do on Plan 9? Does it add DWARF debugging tables to the executable so that the stack can be unwound? Does it play games with setjmp/longjmp? Does it even work at all? Otherwise, a large part of an LLVM project would be a port of some exception mechanism. Does plan9port’s mach-stack(3) have any precedent in Plan 9? and is that the correct basis for exception-like stack unwinding? (I.e., a program unwinding its own stack, rather than a debugger tracing the stack back.) —Joel Salomon P.s.: I am not raising the question of whether exception handling via stack unwinding is a good idea—which has been done to death on this list; see the “Same Functions Everywhere” thread from 2003 at <http://preview.tinyurl.com/cou63b> and message 56 & responses at <http://preview.tinyurl.com/cun6vg>—just asking how to implement it under Plan 9 using the existing tools as far as possible.
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