[Driver] Remove confusing *-linux-android detection with non-android --target=

[MaskRay]

Summary

These values allow, for example, --target=aarch64 and
--target=aarch64-linux-gnu to detect aarch64-linux-android. This is
confusing. Users should specify --target=aarch64-linux-android to get Android GCC
installation.

Reverts D53463.

[MaskRay]

You may need to check whether the Android clang has correct clang -dumpmachine. If not, specify LLVM_HOST_TRIPLE explicitly in CMake.

[pirama]

@nickdesaulniers I presume this is still necessary? See https://reviews.llvm.org/D53463 for why we added this. (The Android kernel build does not use the Android triple.)

[nickdesaulniers]

Sorry, I missed the email for this code review, let me check my filters aren't too agressive.

The Android kernel build does not use the Android triple.

That's no longer the case, so we might as well just wholesale revert D53463 IMO.

[MaskRay]

revert D53463

clang/lib/Driver/ToolChains/Gnu.cpp

/*static*/ void Generic_GCC::GCCInstallationDetector::CollectLibDirsAndTriples(
   // The *Triples variables hard code some triples so that, for example,
   // --target=aarch64 (incomplete triple) can detect lib/aarch64-linux-gnu.
   // They are not needed when the user has correct LLVM_DEFAULT_TARGET_TRIPLE
   // and always uses the full --target (e.g. --target=aarch64-linux-gnu).  The
   // lists should shrink over time. Please don't add more elements to *Triples.
   static const char *const AArch64LibDirs[] = {"/lib64", "/lib"};
   static const char *const AArch64Triples[] = {
       "aarch64-none-linux-gnu", "aarch64-linux-gnu", "aarch64-redhat-linux",
-      "aarch64-suse-linux", "aarch64-linux-android"};
+      "aarch64-suse-linux"};
   static const char *const AArch64beLibDirs[] = {"/lib"};
   static const char *const AArch64beTriples[] = {"aarch64_be-none-linux-gnu",
                                                  "aarch64_be-linux-gnu"};
 
   static const char *const ARMLibDirs[] = {"/lib"};
-  static const char *const ARMTriples[] = {"arm-linux-gnueabi",
-                                           "arm-linux-androideabi"};
+  static const char *const ARMTriples[] = {"arm-linux-gnueabi"};
   static const char *const ARMHFTriples[] = {"arm-linux-gnueabihf",
                                              "armv7hl-redhat-linux-gnueabi",
                                              "armv6hl-suse-linux-gnueabi",
                                              "armv7hl-suse-linux-gnueabi"};
   static const char *const ARMebLibDirs[] = {"/lib"};
-  static const char *const ARMebTriples[] = {"armeb-linux-gnueabi",
-                                             "armeb-linux-androideabi"};
+  static const char *const ARMebTriples[] = {"armeb-linux-gnueabi"};
   static const char *const ARMebHFTriples[] = {
       "armeb-linux-gnueabihf", "armebv7hl-redhat-linux-gnueabi"};
 
   static const char *const AVRLibDirs[] = {"/lib"};
   static const char *const AVRTriples[] = {"avr"};
 
   static const char *const X86_64LibDirs[] = {"/lib64", "/lib"};
   static const char *const X86_64Triples[] = {
       "x86_64-linux-gnu",       "x86_64-unknown-linux-gnu",
       "x86_64-pc-linux-gnu",    "x86_64-redhat-linux6E",
       "x86_64-redhat-linux",    "x86_64-suse-linux",
       "x86_64-manbo-linux-gnu", "x86_64-linux-gnu",
       "x86_64-slackware-linux", "x86_64-unknown-linux",
-      "x86_64-amazon-linux",    "x86_64-linux-android"};
+      "x86_64-amazon-linux"};
   static const char *const X32Triples[] = {"x86_64-linux-gnux32",
                                            "x86_64-pc-linux-gnux32"};
   static const char *const X32LibDirs[] = {"/libx32", "/lib"};
   static const char *const X86LibDirs[] = {"/lib32", "/lib"};
   static const char *const X86Triples[] = {
-      "i586-linux-gnu",     "i686-linux-gnu",
-      "i686-pc-linux-gnu",  "i386-redhat-linux6E",
-      "i686-redhat-linux",  "i386-redhat-linux",
-      "i586-suse-linux",    "i686-montavista-linux",
-      "i686-linux-android", "i686-gnu",
+      "i586-linux-gnu",      "i686-linux-gnu",        "i686-pc-linux-gnu",
+      "i386-redhat-linux6E", "i686-redhat-linux",     "i386-redhat-linux",
+      "i586-suse-linux",     "i686-montavista-linux", "i686-gnu",
   };
 
   static const char *const M68kLibDirs[] = {"/lib"};
   static const char *const M68kTriples[] = {
       "m68k-linux-gnu", "m68k-unknown-linux-gnu", "m68k-suse-linux"};
 
   static const char *const MIPSLibDirs[] = {"/lib"};
   static const char *const MIPSTriples[] = {
       "mips-linux-gnu", "mips-mti-linux", "mips-mti-linux-gnu",
       "mips-img-linux-gnu", "mipsisa32r6-linux-gnu"};
   static const char *const MIPSELLibDirs[] = {"/lib"};
   static const char *const MIPSELTriples[] = {
-      "mipsel-linux-gnu", "mips-img-linux-gnu", "mipsisa32r6el-linux-gnu",
-      "mipsel-linux-android"};
+      "mipsel-linux-gnu", "mips-img-linux-gnu", "mipsisa32r6el-linux-gnu"};
 
   static const char *const MIPS64LibDirs[] = {"/lib64", "/lib"};
   static const char *const MIPS64Triples[] = {
       "mips64-linux-gnu",      "mips-mti-linux-gnu",
       "mips-img-linux-gnu",    "mips64-linux-gnuabi64",
       "mipsisa64r6-linux-gnu", "mipsisa64r6-linux-gnuabi64"};
   static const char *const MIPS64ELLibDirs[] = {"/lib64", "/lib"};
   static const char *const MIPS64ELTriples[] = {
       "mips64el-linux-gnu",      "mips-mti-linux-gnu",
       "mips-img-linux-gnu",      "mips64el-linux-gnuabi64",
-      "mipsisa64r6el-linux-gnu", "mipsisa64r6el-linux-gnuabi64",
-      "mips64el-linux-android"};
+      "mipsisa64r6el-linux-gnu", "mipsisa64r6el-linux-gnuabi64"};
 
   static const char *const MIPSN32LibDirs[] = {"/lib32"};
   static const char *const MIPSN32Triples[] = {"mips64-linux-gnuabin32",
                                                "mipsisa64r6-linux-gnuabin32"};
   static const char *const MIPSN32ELLibDirs[] = {"/lib32"};
   static const char *const MIPSN32ELTriples[] = {
       "mips64el-linux-gnuabin32", "mipsisa64r6el-linux-gnuabin32"};
 

clang/test/Driver/android-gcc-toolchain.c

-// Test that gcc-toolchain option works correctly with a aarch64-linux-gnu
-// triple.
-//
-// RUN: %clang %s -### -v --target=aarch64-linux-gnu \
-// RUN:   --gcc-toolchain=%S/Inputs/basic_android_ndk_tree/ 2>&1 \
-// RUN: | FileCheck %s
-//
-// CHECK: Selected GCC installation: {{.*}}/Inputs/basic_android_ndk_tree/lib/gcc/aarch64-linux-android/4.9