Dear All,
Is there a way to convince xcodebuild to build bitcode files for LLVM for an arbitrary Xcode project? So far, I've been able to get xcodebuild to use LLVM by installing XCode 3.1 and using CC="llvm-gcc" on the command line. I've also managed to get LLVM bitcode generates for intermediate files by using "CC="lvm-gcc -emit-llvm"; however, this gives an error during linking stating that ld does not understand the -emit-llvm option.
Thanks in advance.
-- John T.
In addition to specifying CC, xcodebuild also consults the environment variables LD and LDPLUSPLUS for your linker commands (for C and C++ sources respectively). I would try LD=llvm-gcc and LDPLUSPLUS=llvm-g++ respectively.
In the LINK_SPEC just add %{emit-llvm: } before %{e*} or, if that doesn't work, try %<emit-llvm. One of those should work.
Just to clarify, Mike is talking about modifying llvm-gcc here.
Dear Ted and All,
Thanks. This has helped some. However, I'm now getting errors from libtool about an object being modified after free.
Is libtool supposed to work with LLVM bitcode files? If so, would grabbing the latest source potentially fix the problem (I'm currently using XCode 3.1), or will I need a way to convince xcodebuild to use something other than libtool?
-- John T.
Ted Kremenek wrote:
Hi John,
I'm not certain if libtool works with LLVM bitcode files, and I don't think that all of the tools that manipulate/inspect object files on Mac OS X understand bitcode files either. I suspect that this will change over time.
I believe that Devang and others who implemented LTO on Mac OS X can probably provide you with specific details of tool support for bitcode files.
Ted
Hi John,
I'm not certain if libtool works with LLVM bitcode files, and I don't
think that all of the tools that manipulate/inspect object files on
Mac OS X understand bitcode files either.
Yes. Right now only ld recognizes LLVM bitcode files.
I suspect that this will
change over time.
Yes.
In fact, Xcode 3.1.1 was recently released, and you can get it from here (with an ADC account):
https://connect.apple.com/cgi-bin/WebObjects/MemberSite.woa/wa/getSoftware?bundleID=20214
Xcode 3.1.1 fixes a large number of LTO bugs and a bunch of additional tools in the toolchain now understand LLVM bc files.
-Chris
Ted Kremenek <kremenek <at> apple.com> writes:
In addition to specifying CC, xcodebuild also consults the environment
variables LD and LDPLUSPLUS for your linker commands (for C and C++
sources respectively). I would try LD=llvm-gcc and LDPLUSPLUS=llvm-g+
+ respectively.
Hi Ted,
This does not seem to work anymore if the xcode project has swift code inside
of it, do you have a suggestion?