Emit _fltused on uefi targets as a short-term workaround

[oli-obk]

fixes #62785

I'm not sure how to test this locally. I keep running into problems with compiler-rt when cross compiling via x.py

[rust-highfive]

r? @sfackler

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[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

2019-10-02T09:50:14.5794917Z ##[command]git remote add origin https://github.com/rust-lang/rust
2019-10-02T09:50:14.6016994Z ##[command]git config gc.auto 0
2019-10-02T09:50:14.6066896Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2019-10-02T09:50:14.6135138Z ##[command]git config --get-all http.proxy
2019-10-02T09:50:14.6263286Z ##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/64990/merge:refs/remotes/pull/64990/merge
---
2019-10-02T09:57:15.2365168Z tidy check
2019-10-02T09:57:15.9764357Z * 579 error codes
2019-10-02T09:57:15.9764504Z * highest error code: E0734
2019-10-02T09:57:16.3216334Z * 263 features
2019-10-02T09:57:16.5300122Z tidy error: /checkout/src/libcore/num/f32.rs:12: platform-specific cfg: cfg(target_os = "uefi")
2019-10-02T09:57:16.9944824Z some tidy checks failed
2019-10-02T09:57:16.9945760Z 
2019-10-02T09:57:16.9945760Z 
2019-10-02T09:57:16.9946845Z command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/tidy" "/checkout/src" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0/bin/cargo" "--no-vendor"
2019-10-02T09:57:16.9947244Z 
2019-10-02T09:57:16.9947555Z 
2019-10-02T09:57:16.9951859Z failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test src/tools/tidy
2019-10-02T09:57:16.9952064Z Build completed unsuccessfully in 0:01:30
2019-10-02T09:57:16.9952064Z Build completed unsuccessfully in 0:01:30
2019-10-02T09:57:17.0005378Z == clock drift check ==
2019-10-02T09:57:17.0022141Z   local time: Wed Oct  2 09:57:17 UTC 2019
2019-10-02T09:57:17.1005504Z   network time: Wed, 02 Oct 2019 09:57:17 GMT
2019-10-02T09:57:17.1006145Z == end clock drift check ==
2019-10-02T09:57:18.4771770Z ##[error]Bash exited with code '1'.
2019-10-02T09:57:18.4803541Z ##[section]Starting: Checkout
2019-10-02T09:57:18.4805718Z ==============================================================================
2019-10-02T09:57:18.4805774Z Task         : Get sources
2019-10-02T09:57:18.4805844Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[sfackler]

r? @alexcrichton

[12101111]

It seems that we can't put platform-specific things in libcore.
Also, i686-unknown-uefi don't need this workaround as it's based on i686-unknown-windows-gnu.

[alexcrichton]

Thanks for this! I think though this static may perhaps be best placed in compiler-builtins rather than libcore? That way it should get properly hidden visibility and such

[oli-obk]

I opened rust-lang/compiler-builtins#317

Also, i686-unknown-uefi don't need this workaround as it's based on i686-unknown-windows-gnu.

I changed it to only apply to x86_64-unknown-uefi

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed (pretty log, raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

2019-10-02T15:38:21.4759820Z ##[command]git remote add origin https://github.com/rust-lang/rust
2019-10-02T15:38:21.4934743Z ##[command]git config gc.auto 0
2019-10-02T15:38:21.5018623Z ##[command]git config --get-all http.https://github.com/rust-lang/rust.extraheader
2019-10-02T15:38:21.5074358Z ##[command]git config --get-all http.proxy
2019-10-02T15:38:21.5207380Z ##[command]git -c http.extraheader="AUTHORIZATION: basic ***" fetch --force --tags --prune --progress --no-recurse-submodules --depth=2 origin +refs/heads/*:refs/remotes/origin/* +refs/pull/64990/merge:refs/remotes/pull/64990/merge
---
2019-10-02T16:38:29.4643323Z .................................................................................................... 1500/9087
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---
2019-10-02T16:48:58.7898719Z ...............................................................................................i.... 9000/9087
2019-10-02T16:49:10.0703768Z .......................................................................................
2019-10-02T16:49:10.0703992Z failures:
2019-10-02T16:49:10.0736584Z 
2019-10-02T16:49:10.0737622Z ---- [ui] ui/uefi-float.rs stdout ----
2019-10-02T16:49:10.0737902Z error: test compilation failed although it shouldn't!
2019-10-02T16:49:10.0737947Z status: exit code: 1
2019-10-02T16:49:10.0737947Z status: exit code: 1
2019-10-02T16:49:10.0738555Z command: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "/checkout/src/test/ui/uefi-float.rs" "-Zthreads=1" "--target=x86_64-unknown-linux-gnu" "--error-format" "json" "-Zui-testing" "-C" "prefer-dynamic" "--out-dir" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/uefi-float" "-Crpath" "-O" "-Cdebuginfo=0" "-Zunstable-options" "-Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "-L" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui/uefi-float/auxiliary" "-A" "unused"
2019-10-02T16:49:10.0739058Z ------------------------------------------
2019-10-02T16:49:10.0739087Z 
2019-10-02T16:49:10.0739269Z ------------------------------------------
2019-10-02T16:49:10.0739328Z stderr:
2019-10-02T16:49:10.0739328Z stderr:
2019-10-02T16:49:10.0739505Z ------------------------------------------
2019-10-02T16:49:10.0739547Z error: language item required, but not found: `eh_personality`
2019-10-02T16:49:10.0739631Z error: aborting due to previous error
2019-10-02T16:49:10.0739654Z 
2019-10-02T16:49:10.0739675Z 
2019-10-02T16:49:10.0739855Z ------------------------------------------
2019-10-02T16:49:10.0739855Z ------------------------------------------
2019-10-02T16:49:10.0739898Z 
2019-10-02T16:49:10.0739918Z 
2019-10-02T16:49:10.0739939Z 
2019-10-02T16:49:10.0739983Z failures:
2019-10-02T16:49:10.0740154Z     [ui] ui/uefi-float.rs
2019-10-02T16:49:10.0740422Z test result: FAILED. 9048 passed; 1 failed; 38 ignored; 0 measured; 0 filtered out
2019-10-02T16:49:10.0740461Z 
2019-10-02T16:49:10.0776178Z thread 'main' panicked at 'Some tests failed', src/tools/compiletest/src/main.rs:537:22
2019-10-02T16:49:10.0776263Z note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
2019-10-02T16:49:10.0776263Z note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace.
2019-10-02T16:49:10.0794529Z 
2019-10-02T16:49:10.0794605Z 
2019-10-02T16:49:10.0797425Z command did not execute successfully: "/checkout/obj/build/x86_64-unknown-linux-gnu/stage0-tools-bin/compiletest" "--compile-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib" "--run-lib-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/lib/rustlib/x86_64-unknown-linux-gnu/lib" "--rustc-path" "/checkout/obj/build/x86_64-unknown-linux-gnu/stage2/bin/rustc" "--src-base" "/checkout/src/test/ui" "--build-base" "/checkout/obj/build/x86_64-unknown-linux-gnu/test/ui" "--stage-id" "stage2-x86_64-unknown-linux-gnu" "--mode" "ui" "--target" "x86_64-unknown-linux-gnu" "--host" "x86_64-unknown-linux-gnu" "--llvm-filecheck" "/usr/lib/llvm-6.0/bin/FileCheck" "--host-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--target-rustcflags" "-Crpath -O -Cdebuginfo=0 -Zunstable-options  -Lnative=/checkout/obj/build/x86_64-unknown-linux-gnu/native/rust-test-helpers" "--docck-python" "/usr/bin/python2.7" "--lldb-python" "/usr/bin/python2.7" "--gdb" "/usr/bin/gdb" "--quiet" "--llvm-version" "6.0.0\n" "--system-llvm" "--cc" "" "--cxx" "" "--cflags" "" "--llvm-components" "" "--llvm-cxxflags" "" "--adb-path" "adb" "--adb-test-dir" "/data/tmp/work" "--android-cross-path" "" "--color" "always"
2019-10-02T16:49:10.0797701Z 
2019-10-02T16:49:10.0797750Z 
2019-10-02T16:49:10.0804316Z failed to run: /checkout/obj/build/bootstrap/debug/bootstrap test
2019-10-02T16:49:10.0804390Z Build completed unsuccessfully in 1:03:35
2019-10-02T16:49:10.0804390Z Build completed unsuccessfully in 1:03:35
2019-10-02T16:49:10.0856506Z == clock drift check ==
2019-10-02T16:49:10.0871170Z   local time: Wed Oct  2 16:49:10 UTC 2019
2019-10-02T16:49:10.6077881Z   network time: Wed, 02 Oct 2019 16:49:10 GMT
2019-10-02T16:49:10.6078699Z == end clock drift check ==
2019-10-02T16:49:11.7296401Z ##[error]Bash exited with code '1'.
2019-10-02T16:49:11.7341680Z ##[section]Starting: Checkout
2019-10-02T16:49:11.7344493Z ==============================================================================
2019-10-02T16:49:11.7344552Z Task         : Get sources
2019-10-02T16:49:11.7344622Z Description  : Get sources from a repository. Supports Git, TfsVC, and SVN repositories.

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)