[PATCH] [ASan] Only include rpc headers if they are available.

[Yury Gribov]

REPOSITORY
  rL LLVM

================
Comment at: CMakeLists.txt:183
@@ -182,1 +182,3 @@
 check_include_file(unwind.h HAVE_UNWIND_H)
+check_include_file(rpc/xdr.h HAVE_RPC_XDR_H)
+check_include_file(tirpc/rpc/xdr.h HAVE_TIRPC_XDR_H)
----------------
kcc wrote:
> ygribov wrote:
> > kcc wrote:
> > > Can you do it w/o cmake checks? 
> > > asan rt is built by many build systems, some of which you don't have access to, 
> > > and some of which I don't have access to. 
> > > All such checks should be done in the sources code. 
> > > Can you do it w/o cmake checks? 
> > 
> > I don't think so, Glibc headers do not have any marker to identify whether xdr.h is available or not.
> > 
> > > asan rt is built by many build systems, some of which you don't have access to
> > 
> > I'll do the Autoconf part in GCC myself. As for other build systems I think we can safely assume that checking 
> > for existence of header should be well supported.
> Can't you rely on the glibc version? 
> Anyway, at the very least, the code should build on a modern glibc w/o needing extra compile flags.
> 
> I.e. provide default values for these macros in a header file (sanitizer_platform_limits_posix.h?)
> Then, If you don't need the cmake part here, just drop it. 
> 
> 
> Can't you rely on the glibc version?

No, Glibc is not guaranteed to include xdr.h regardless of version. If boils down to distribution maintainer deciding whether he wants to build his glibc with --enable-obsolete-rpc or not.

> Anyway, at the very least, the code should build on a modern glibc w/o needing extra compile flags.
> I.e. provide default values for these macros
> in a header file (sanitizer_platform_limits_posix.h?)

You mean throw in safe ifndefs? Makes sense. While at it, is the rest of the patch fine?

> All such checks should be done in the sources code.

But don't we already have tons of configury done in buildscripts? Like ASAN_LOW_MEMORY=1, etc.

http://reviews.llvm.org/D8698

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