commit 509a8904e3efa1db01b76f01ee57ace55968bc29
Author: Tiancong Wang <tcwang@google.com>
Date:   Tue Nov 24 09:51:53 2020 -0800

    Revert "[Driver] -B: don't search for target triple prefixes"
    
    This reverts commit 3452a0d8c17f7166f479706b293caf6ac76ffd90.

diff --git a/clang/lib/Driver/Driver.cpp b/clang/lib/Driver/Driver.cpp
index 4ac813718ea..9db285adb64 100644
--- a/clang/lib/Driver/Driver.cpp
+++ b/clang/lib/Driver/Driver.cpp
@@ -4865,7 +4865,8 @@ void Driver::generatePrefixedToolNames(
     Names.emplace_back((DefaultTargetTriple + "-" + Tool).str());
 }
 
-static bool ScanDirForExecutable(SmallString<128> &Dir, StringRef Name) {
+static bool ScanDirForExecutable(SmallString<128> &Dir,
+                                 const std::string &Name) {
   llvm::sys::path::append(Dir, Name);
   if (llvm::sys::fs::can_execute(Twine(Dir)))
     return true;
@@ -4882,8 +4883,9 @@ std::string Driver::GetProgramPath(StringRef Name, const ToolChain &TC) const {
   for (const auto &PrefixDir : PrefixDirs) {
     if (llvm::sys::fs::is_directory(PrefixDir)) {
       SmallString<128> P(PrefixDir);
-      if (ScanDirForExecutable(P, Name))
-        return std::string(P.str());
+      for (const auto &TargetSpecificExecutable : TargetSpecificExecutables)
+        if (ScanDirForExecutable(P, TargetSpecificExecutable))
+          return std::string(P.str());
     } else {
       SmallString<128> P((PrefixDir + Name).str());
       if (llvm::sys::fs::can_execute(Twine(P)))
diff --git a/clang/test/Driver/B-opt.c b/clang/test/Driver/B-opt.c
index df85dee4b70..5e5ff42fd09 100644
--- a/clang/test/Driver/B-opt.c
+++ b/clang/test/Driver/B-opt.c
@@ -1,10 +1,9 @@
 // Check -B driver option.
-
-/// Target triple prefix is not detected for -B.
+//
 // RUN: %clang %s -### -o %t.o -target i386-unknown-linux \
 // RUN:     -B %S/Inputs/B_opt_tree/dir1 -fuse-ld=ld 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-B-OPT-TRIPLE %s
-// CHECK-B-OPT-TRIPLE-NOT: "{{.*}}/Inputs/B_opt_tree/dir1{{/|\\\\}}i386-unknown-linux-ld"
+// CHECK-B-OPT-TRIPLE: "{{.*}}/Inputs/B_opt_tree/dir1{{/|\\\\}}i386-unknown-linux-ld"
 //
 // RUN: %clang %s -### -o %t.o -target i386-unknown-linux \
 // RUN:     -B %S/Inputs/B_opt_tree/dir2 -fuse-ld=ld 2>&1 \
diff --git a/clang/test/Driver/fuse-ld.c b/clang/test/Driver/fuse-ld.c
index 678913dd84c..9b90307ecec 100644
--- a/clang/test/Driver/fuse-ld.c
+++ b/clang/test/Driver/fuse-ld.c
@@ -32,21 +32,23 @@
 // RUN:   | FileCheck %s -check-prefix=CHECK-FREEBSD-PLIB
 // CHECK-FREEBSD-PLIB: error: invalid linker name
 
+
+
 // RUN: %clang %s -### -fuse-ld=ld \
 // RUN:     -target arm-linux-androideabi \
-// RUN:     -B%S/Inputs/basic_android_tree/bin/arm-linux-androideabi- 2>&1 \
+// RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-ANDROID-ARM-LD
 // CHECK-ANDROID-ARM-LD: Inputs/basic_android_tree/bin{{/|\\+}}arm-linux-androideabi-ld
 
 // RUN: %clang %s -### -fuse-ld=bfd \
 // RUN:     -target arm-linux-androideabi \
-// RUN:     -B%S/Inputs/basic_android_tree/bin/arm-linux-androideabi- 2>&1 \
+// RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=CHECK-ANDROID-ARM-BFD
 // CHECK-ANDROID-ARM-BFD: Inputs/basic_android_tree/bin{{/|\\+}}arm-linux-androideabi-ld.bfd
 
 // RUN: %clang %s -### -fuse-ld=gold \
 // RUN:     -target arm-linux-androideabi \
-// RUN:     -B%S/Inputs/basic_android_tree/bin/arm-linux-androideabi- 2>&1 \
+// RUN:     -B%S/Inputs/basic_android_tree/bin 2>&1 \
 // RUN:   | FileCheck %s -check-prefix=CHECK-ANDROID-ARM-GOLD
 // CHECK-ANDROID-ARM-GOLD: Inputs/basic_android_tree/bin{{/|\\+}}arm-linux-androideabi-ld.gold
 
diff --git a/clang/test/Driver/prefixed-tools.c b/clang/test/Driver/prefixed-tools.c
index 0252a2f7014..63f7f29ae96 100644
--- a/clang/test/Driver/prefixed-tools.c
+++ b/clang/test/Driver/prefixed-tools.c
@@ -1,8 +1,8 @@
-// RUN: %clang -### -B%S/Inputs/prefixed_tools_tree/x86_64--linux- -o %t.o -no-integrated-as -fuse-ld=ld \
+// RUN: %clang -### -B%S/Inputs/prefixed_tools_tree -o %t.o -no-integrated-as -fuse-ld=ld \
 // RUN:        -target x86_64--linux %s 2>&1 | \
 // RUN: FileCheck --check-prefix=CHECK-M64 %s
 
-// RUN: %clang -### -B%S/Inputs/prefixed_tools_tree/x86_64--linux- -o %t.o -no-integrated-as -fuse-ld=ld \
+// RUN: %clang -### -B%S/Inputs/prefixed_tools_tree -o %t.o -no-integrated-as -fuse-ld=ld \
 // RUN:        -m32 -target x86_64--linux %s 2>&1 | \
 // RUN: FileCheck --check-prefix=CHECK-M32 %s
 
diff --git a/clang/test/Driver/program-path-priority.c b/clang/test/Driver/program-path-priority.c
index cba5f9f4d74..9f1109f530c 100644
--- a/clang/test/Driver/program-path-priority.c
+++ b/clang/test/Driver/program-path-priority.c
@@ -119,15 +119,15 @@
 // RUN: test -f %t/%target_triple-gcc && \
 // RUN:   mv %t/%target_triple-gcc %t/prefix || true
 // RUN: touch %t/notreal-none-elf-gcc && chmod +x %t/notreal-none-elf-gcc
-// RUN: touch %t/prefix/gcc && chmod +x %t/prefix/gcc
 // RUN: env "PATH=" %t/clang -### -target notreal-none-elf %s -B %t/prefix 2>&1 | \
 // RUN:   FileCheck --check-prefix=DEFAULT_TRIPLE_IN_PREFIX %s
-// DEFAULT_TRIPLE_IN_PREFIX: prefix/gcc"
+// DEFAULT_TRIPLE_IN_PREFIX: prefix/{{.*}}-gcc"
 // DEFAULT_TRIPLE_IN_PREFIX-NOT: notreal-none-elf-gcc"
 
 /// Only if there is nothing in the prefix will we search other paths
 /// -f in case $DEFAULT_TRIPLE == %target_triple
-// RUN: rm -f %t/prefix/$DEFAULT_TRIPLE-gcc %t/prefix/%target_triple-gcc %t/prefix/gcc
+// RUN: rm -f %t/prefix/$DEFAULT_TRIPLE-gcc
+// RUN: rm -f %t/prefix/%target_triple-gcc
 // RUN: env "PATH=" %t/clang -### -target notreal-none-elf %s -B %t/prefix 2>&1 | \
 // RUN:   FileCheck --check-prefix=EMPTY_PREFIX_DIR %s
 // EMPTY_PREFIX_DIR: notreal-none-elf-gcc"
diff --git a/clang/test/Driver/windows-cross.c b/clang/test/Driver/windows-cross.c
index 96497da61c0..d96b0283a90 100644
--- a/clang/test/Driver/windows-cross.c
+++ b/clang/test/Driver/windows-cross.c
@@ -1,47 +1,47 @@
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -stdlib=libstdc++ -rtlib=compiler-rt -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-BASIC-LIBCXX
 
-// CHECK-BASIC-LIBCXX: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{[^"]*}}.o" "-lmsvcrt"
+// CHECK-BASIC-LIBCXX: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{[^"]*}}.o" "-lmsvcrt"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -stdlib=libstdc++ -rtlib=compiler-rt -static -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-STATIC
 
-// CHECK-STATIC: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bstatic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{[^"]*}}.o" "-lmsvcrt"
+// CHECK-STATIC: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bstatic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{[^"]*}}.o" "-lmsvcrt"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %s/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -rtlib=compiler-rt -stdlib=libstdc++ -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-RTLIB
 
-// CHECK-RTLIB: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
+// CHECK-RTLIB: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -rtlib=compiler-rt -stdlib=libc++ -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-C-LIBCXX
 
-// CHECK-C-LIBCXX: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
+// CHECK-C-LIBCXX: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
 
 // RUN: %clangxx -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -rtlib=compiler-rt -stdlib=libc++ -o /dev/null %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-LIBCXX
 
-// CHECK-LIBCXX: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}.o" "-lc++" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
+// CHECK-LIBCXX: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-Bdynamic" "--entry" "mainCRTStartup" "--allow-multiple-definition" "-o" "{{[^"]*}}" "{{.*}}.o" "-lc++" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -shared -rtlib=compiler-rt -stdlib=libc++ -o shared.dll %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-SHARED
 
-// CHECK-SHARED: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bdynamic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
+// CHECK-SHARED: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bdynamic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -shared -rtlib=compiler-rt -stdlib=libc++ -static -o shared.dll %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-SHARED-STATIC
 
-// CHECK-SHARED-STATIC: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bstatic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
+// CHECK-SHARED-STATIC: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bstatic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %s/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -shared -rtlib=compiler-rt -stdlib=libc++ -nostartfiles -o shared.dll %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-NOSTARTFILES
 
-// CHECK-NOSTARTFILES: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bdynamic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
+// CHECK-NOSTARTFILES: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bdynamic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o" "-lmsvcrt" "{{.*[\\/]}}clang_rt.builtins-arm.lib"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=ld -shared -rtlib=compiler-rt -stdlib=libc++ -nostartfiles -nodefaultlibs -o shared.dll %s 2>&1 \
 // RUN:   | FileCheck %s --check-prefix CHECK-STANDALONE
 
-// CHECK-STANDALONE: {{[/\\]}}ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bdynamic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o"
+// CHECK-STANDALONE: armv7-windows-itanium-ld" "--sysroot={{.*}}/Inputs/Windows/ARM/8.1" "-m" "thumb2pe" "-shared" "-Bdynamic" "--enable-auto-image-base" "--entry" "_DllMainCRTStartup" "--allow-multiple-definition" "-o" "shared.dll" "--out-implib" "shared.lib" "{{.*}}.o"
 
 // RUN: %clang -### -target armv7-windows-itanium --sysroot %S/Inputs/Windows/ARM/8.1 -B %S/Inputs/Windows/ARM/8.1/usr/bin -fuse-ld=lld-link2 -shared -o shared.dll -x c++ %s 2>&1 \
 // RUN:    | FileCheck %s --check-prefix CHECK-FUSE-LD