OS X: Wrong CMake flag: " LLVM_DEFAULT_TARGET_TRIPLE=x86_64-unknown-linux-gnu"

[IngwiePhoenix]

> /Users/Ingwie/Work/Git/mrustc/bin/mrustc lib/libproc_macro/src/lib.rs --crate-name proc_macro --crate-type rlib -g --cfg debug_assertions -O -o output/libproc_macro.hir -L output
cd rustc-1.19.0-src/build && cmake -D LLVM_TARGET_ARCH=x86_64 -D LLVM_DEFAULT_TARGET_TRIPLE=x86_64-unknown-linux-gnu -D LLVM_TARGETS_TO_BUILD="X86;ARM;AArch64" -D LLVM_ENABLE_ASSERTIONS=OFF -D LLVM_INCLUDE_EXAMPLES=OFF -D LLVM_INCLUDE_TESTS=OFF -D LLVM_INCLUDE_DOCS=OFF -D LLVM_ENABLE_ZLIB=OFF -D LLVM_ENABLE_TERMINFO=OFF -D LLVM_ENABLE_LIBEDIT=OFF -D WITH_POLLY=OFF -D CMAKE_CXX_COMPILER="clang++" -D CMAKE_C_COMPILER="clang" -D CMAKE_BUILD_TYPE=RelWithDebInfo ../src/llvm

When I saw this command floating by on my terminal, I immediately tilted my head - because this is pretty much not correct. On my case, it should be passing x86_64-apple-darwin instead. Any idea why this is happening?

[IngwiePhoenix]

This happened somewhat later in the build:

[ 87%] Linking CXX shared library ../../lib/libLTO.dylib
ld: unknown option: -z
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[3]: *** [lib/libLTO.dylib] Error 1
make[2]: *** [tools/lto/CMakeFiles/LTO.dir/all] Error 2
make[1]: *** [all] Error 2
make: *** [rustc-1.19.0-src/build/bin/llvm-config] Error 2
[email protected] ~/W/g/mrustc $ 

I don't know how to make this give me verbose output, so this is currently all I have. :)

[thepowersgang]

The incorrect target is being passed because the makefile (minicargo.mk) has a semi-hard-coded rustc target of x86_64-unknown-linux-gnu (with no magical autodetection).

It's kinda a moot point at the moment, because OSX builds don't work (linking errors creating the final executable)

[IngwiePhoenix]

Huh? No. It built perfectly, actually :)

[email protected] ~/W/G/mrustc $ ./bin/mrustc --version
MRustC v0.8.0 master:1a3c5dfc
- Build time: Mon, 04 Feb 2019 00:17:38 +0000
- Commit: 1a3c5dfcab0776c9a9a057303f823cec16386517

Well the target-passing makes sense now. Thanks :)

EDIT
The only thing not working is building rustc using mrustc, though. Looking at the error I posted again, the GNU linker might be expected. I do have a GCC installation - so maybe I can pass the paths to this installation instead, so my main toolchain (Apple's command line tools) isn't used?

CC=/usr/local/opt/gcc@7/bin/gcc
CXX=/usr/local/opt/gcc@7/bin/g++
(?) LD=/usr/local/opt/gcc@7/bin/gcc

The default linker is here: /usr/bin/ld
Looking at it's man-page reveals that it only supports -Z and not -z. Meanwhile, looking at one of my cross-compiler setups:

$ /usr/local/psxsdk/bin/mipsel-unknown-elf-ld --help | grep -- -z
  -z common-page-size=SIZE    Set common page size to SIZE
  -z max-page-size=SIZE       Set maximum page size to SIZE
  -z defs                     Report unresolved symbols in object files
  -z muldefs                  Allow multiple definitions
  -z execstack                Mark executable as requiring executable stack
  -z noexecstack              Mark executable as not requiring executable stack
  -z globalaudit              Mark executable requiring global auditing
  -z combreloc                Merge dynamic relocs into one section and sort
  -z nocombreloc              Don't merge dynamic relocs into one section
  -z global                   Make symbols in DSO available for subsequently
  -z initfirst                Mark DSO to be initialized first at runtime
  -z interpose                Mark object to interpose all DSOs but executable
  -z lazy                     Mark object lazy runtime binding (default)
  -z loadfltr                 Mark object requiring immediate process
  -z nocopyreloc              Don't create copy relocs
  -z nodefaultlib             Mark object not to use default search paths
  -z nodelete                 Mark DSO non-deletable at runtime
  -z nodlopen                 Mark DSO not available to dlopen
  -z nodump                   Mark DSO not available to dldump
  -z now                      Mark object non-lazy runtime binding
  -z origin                   Mark object requiring immediate $ORIGIN
  -z relro                    Create RELRO program header
  -z norelro                  Don't create RELRO program header (default)
  -z separate-code            Create separate code program header
  -z noseparate-code          Don't create separate code program header (default)
  -z common                   Generate common symbols with STT_COMMON type
  -z nocommon                 Generate common symbols with STT_OBJECT type
  -z stack-size=SIZE          Set size of stack segment
  -z text                     Treat DT_TEXTREL in shared object as error
  -z notext                   Don't treat DT_TEXTREL in shared object as error
  -z textoff                  Don't treat DT_TEXTREL in shared object as error

So this is appearently a GNU linker vs. LLVM linker difference... Any workaround here?

[thepowersgang]

Not built in - as said, OSX isn't working (I don't have a OSX machine easily accessible, so I can't do much work on it)

The bit that doesn't work isn't building mrustc (that usually works properly), it's building anything with mrustc (see https://travis-ci.org/thepowersgang/mrustc/jobs/490819360)

If you're able to get things working on OSX (particularly working on travis), I'm open to a pull request.

[thepowersgang]

There have been quite a few macos improvements recently, have any of these fixed the remaining issues?

The original issue (LLVM_DEFAULT_TARGET_TRIPLE) has been fixed.