[PATCH] D71848: Allow the discovery of Android NDK's triple-prefixed binaries.

[James Y Knight via Phabricator via cfe-commits]

jyknight added a comment.

Since this change is not android-only, please update change description, and update some non-android tests.

E.g. maybe the tests in clang/test/Driver/linux-ld.c for ubuntu_14.04_multiarch_tree should check the path at which ld is found. While the existing Inputs/ubuntu_14.04_multiarch_tree doesn't have any "ld" files populated, and the tests aren't checking for ld's path at all, it would be reasonable to add such files and then check the result.

This is what the layout of the "ld" files look like in current ubuntu versions on x86_64. It seems that it was almost the same back in 2014 -- except the triple-less names were the primary file, and the others linked to them. That's not really relevant to the test, anyways, just the filenames existing and being executable.

  lrwxrwxrwx  /usr/bin/ld.bfd -> x86_64-linux-gnu-ld.bfd
  lrwxrwxrwx  /usr/bin/ld.gold -> x86_64-linux-gnu-ld.gold
  lrwxrwxrwx  /usr/bin/ld -> x86_64-linux-gnu-ld
  -rwxr-xr-x  /usr/bin/x86_64-linux-gnu-ld.bfd
  -rwxr-xr-x  /usr/bin/x86_64-linux-gnu-ld.gold
  -rwxr-xr-x  /usr/bin/x86_64-linux-gnu-ld -> x86_64-linux-gnu-ld.bfd
  -rwxr-xr-x  /usr/bin/powerpc64le-linux-gnu-ld.bfd
  -rwxr-xr-x  /usr/bin/powerpc64le-linux-gnu-ld.gold
  -rwxr-xr-x  /usr/bin/powerpc64le-linux-gnu-ld -> powerpc64le-linux-gnu-ld.bfd

Before this clang patch, we would've defaulted to /usr/bin/ld unless the target string was specified exactly as "x86_64-linux-gnu" or "powerpc64le-linux-gnu". Afterwards, we can also chose those tools for any other triple which we can detect as matching those gcc installation triples.

This would even have the useful effect of allowing an invocation like "clang -target powerpc64le-unknown-linux-gnu" to work, which it doesn't do currently -- because it defaults to /usr/bin/ld, which is an x86_64 linker.



================
Comment at: clang/lib/Driver/ToolChains/Gnu.cpp:2578
     getProgramPaths().push_back(getDriver().Dir);
+  getProgramPrefixes().push_back(Twine(GCCInstallation.getTriple().str() + "-").str());
+
----------------
I suspect this doesn't actually work here, since GCCInstallation.init() hasn't yet been called. But you have the same in Linux.cpp, after the init() call, which seems better.



================
Comment at: clang/lib/Driver/ToolChains/Linux.cpp:242
                          .str());
+    PPrefixes.push_back(Twine(GCCInstallation.getTriple().str() + "-").str());
   }
----------------
Probably should check that GCCInstallation.getTriple() != Triple before adding, in order to avoid duplicating entries in the search-list.


================
Comment at: clang/test/Driver/android-triple-version.c:1
+// Android's target triples can contain a version number in the environment
+// field (e.g. arm-linux-androideabi9).
----------------
This seems like too many test-cases. It doesn't seem to me that they're actually adding any meaningful coverage, after the first 3?


================
Comment at: clang/test/Driver/android-triple-version.c:6
+// Ensure no execute permissions on .../bin/{target-triple}/ld.
+// RUN: chmod -x %S/Inputs/basic_android_ndk_tree/arm-linux-androideabi/bin/ld
+// RUN: chmod -x %S/Inputs/basic_android_ndk_tree/aarch64-linux-android/bin/ld
----------------
You shouldn't edit files in the Inputs tree (or add/remove files there either). If this script stops, it may be left in an edited state, which would be bad. Also, sometimes it might be read-only.

Another way to achieve this test goal may be with -fuse-ld=prefixtest, and then create bin/$triple-ld.prefixtest, but not $triple/bin/ld.prefixtest


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D71848/new/

https://reviews.llvm.org/D71848