rustbuild should compile rsbegin/rsend for TARGET not for HOST

[japaric]

Because that's what the old build system does:

LD_LIBRARY_PATH=/home/japaric/x86_64-unknown-linux-gnu/stage2/lib:/usr/lib:$LD_LIBRARY_PATH   x86_64-unknown-linux-gnu/stage2/bin/rustc --cfg stage2  -O --cfg rtopt -C rpath  --target=x86_64-pc-windows-gnu -C linker=x86_64-w64-mingw32-gcc -C ar=x86_64-w64-mingw32-ar   --emit=obj -o x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-pc-windows-gnu/lib/rsbegin.o /shared/rust/master/src/rtstartup/rsbegin.rs

but rustbuild doesn't pass the --target and rsbegin.o ends up being an ELF on linux:

$ file $(find -name rsbegin.o)
./build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-pc-windows-gnu/lib/rsbegin.o: ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped

The fix should be simple in theory. You just have to pass --target $TARGET to the Command in the code linked above. But then you run in problems with the order of the operations: "core not found for $TARGET".

Meta

$ git rev-parse HEAD
e77d86c142ae668038dd43594d04022cbd6bf4d8

cc @alexcrichton

[japaric]

FWIW, trying to cross compile to i686-pc-windows-gnu I get this:

   Compiling std v0.0.0 (file:///shared/rust/master/src/libstd)
error: linking with `i686-w64-mingw32-gcc` failed: exit code: 1
  |
  = note: "i686-w64-mingw32-gcc" "-Wl,--enable-long-section-names" "-fno-use-linker-plugin" "-Wl,--nxcompat" "-nostdlib" "-Wl,--large-address-aware" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/i686-pc-windows-gnu/lib/dllcrt2.o" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/i686-pc-windows-gnu/lib/rsbegin.o" "-L" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/i686-pc-windows-gnu/lib" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1-std/i686-pc-windows-gnu/release/deps/std-e2265790837cbaa9.0.o" "-o" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1-std/i686-pc-windows-gnu/release/deps/std-e2265790837cbaa9.dll" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1-std/i686-pc-windows-gnu/release/deps/std-e2265790837cbaa9.metadata.o" "-nodefaultlibs" "-L" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1-std/i686-pc-windows-gnu/release/deps" "-L" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1-std/i686-pc-windows-gnu/release/build/std-a76d8b43f160511e/out/.libs" "-L" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1-std/i686-pc-windows-gnu/release/build/alloc_jemalloc-b4a9fdd2a74b7a98/out/lib" "-L" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/i686-pc-windows-gnu/lib" "-Wl,-Bstatic" "-Wl,--whole-archive" "-l" "backtrace" "-Wl,--no-whole-archive" "-Wl,-Bdynamic" "-l" "advapi32" "-l" "ws2_32" "-l" "userenv" "-l" "shell32" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/libcollections-f1089b41bd63d58e.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/libpanic_unwind-3976021b89fe79d0.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/liballoc-bc4e10ff5ace48d6.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/liballoc_system-0126d25e93e8a210.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/librustc_unicode-42e6477b8bd9d820.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/libunwind-7f3a35b0cd66ef0a.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/liblibc-6f0a493cfbc94393.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/librand-8de767ad0539476d.rlib" "-Wl,--no-whole-archive" "-Wl,--whole-archive" "/tmp/rustc.EO8OdN3FN33s/libcore-bf8588192495524e.rlib" "-Wl,--no-whole-archive" "-l" "gcc_eh" "-l" "gcc_eh" "-shared" "-l" "compiler-rt" "-lmingwex" "-lmingw32" "-lgcc" "-lmsvcrt" "-luser32" "-lkernel32" "/home/japaric/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/i686-pc-windows-gnu/lib/rsend.o"
  = note: /home/japaric/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/i686-pc-windows-gnu/lib/rsbegin.o: file not recognized: File format not recognized
collect2: error: ld returned 1 exit status


error: aborting due to previous error

error: Could not compile `std`.

Trying to cross compile to x86_64-pc-windows-gnu results in #36291

[alexcrichton]

Yeah not passing --target would do it, should be easy to add though! (I think that's all that's necessary)

[japaric]

Yeah not passing --target would do it,

Actually, the solution is the opposite. rustbuild is building these startup files for linux but it should compile them for windows hence the --target $WINDOWSY_TARGET has to be added.

[alexcrichton]

Oh right sorry "it" there was "would cause this problem", we should indeed pass --target!