[llvm-commits] [PATCH] Splitting PACKAGE_VERSION and friends out of config.h

[Frits van Bommel]

On Sat, Nov 20, 2010 at 4:54 PM, Francois Pichet <pichet2000 at gmail.com> wrote:
> Speaking of massive recompilation, revision 117102 in TableGen,cmake
> is causing LLVMX86CodeGen and all its dependencies to always be
> recompiled even if nothing has changed at least on MSVC 2008. I
> thought that issue was gone but it is still there. I forgot I had
> reverted to a previous version.

That's weird, it works fine when generating makefiles.
Maybe MSVC doesn't check whether running a target changed the output
file, but instead assumes all targets that depend on it must also be
rebuilt?

For reference, r117102 introduces for each tablegen-generated file a
target that checks whether the latest tablegen output differs from the
one currently in use. This target always runs if the tablegen
executable is newer than the last significant change to the output
file.

If that turns out to be the problem, does anyone know how to fix that?
(Other than reverting it and going back to recompiling all files
depending on tablegen output whenever tablegen is relinked even if the
output hasn't changed, I mean)