On Sun, Jul 08, 2007 at 04:07:59PM +0100, Andrew Coppin wrote:
The way I heard it is that it *does* native code generation, but it's "not as good" as the via-C version. (Can't imagine why... You would have thought directly implementing functional primitives would be much easier than trying to mangle them to fit C's multitude of limitations. Still, what do I know?)
This is very true - but -fvia-C isn't really C. First it generates GCC C (with global register variables, among other things), then it feeds the output through gcc - and then it runs a GHC-specific Perl script called the Evil Mangler over the assembly output, which promptly regexes your code to death. If you want to see what a difference exists between true C and the NCG, try compiling your program with -fvia-C -unreg. -unreg tells GHC to generate (something very close to) ANSI C; also, the mangler is not used. -unreg is mainly used for porting... Stefan