BareMetal: detect usr/include/c++/v1 path in sysroot

[manojgupta]

Summary

Currently baremetal driver adds <sysroot>/include/c++/v1
for libc++ headers. However on ChromeOS, all include files
are inside <sysroot>/usr/include. So add
<sysroot>/usr/include/c++/v1 if it exists in baremetal driver.

[manojgupta]

friendly ping for review.

[MaskRay]

LGTM.

clang/test/Driver/baremetal.cpp

77

Delete unused -no-canonical-prefixes and -o %t.o

Change legacy -target to --target=

85

It's not necessary to test the linker name. -Bstatic is a good enough indicator.

[manojgupta]

address comments and check CI.

clang/lib/Driver/ToolChains/BareMetal.cpp

 
 void BareMetal::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                                              ArgStringList &CC1Args) const {
   if (DriverArgs.hasArg(options::OPT_nostdinc) ||
       DriverArgs.hasArg(options::OPT_nostdlibinc) ||
       DriverArgs.hasArg(options::OPT_nostdincxx))
     return;
 
+  const Driver &D = getDriver();
   std::string SysRoot(computeSysRoot());
   if (SysRoot.empty())
     return;
 
   switch (GetCXXStdlibType(DriverArgs)) {
   case ToolChain::CST_Libcxx: {
+    // First check sysroot/usr/include/c++/v1 if it exists.
+    SmallString<128> TargetDir(SysRoot);
+    llvm::sys::path::append(TargetDir, "usr", "include", "c++", "v1");
+    if (D.getVFS().exists(TargetDir)) {
+      addSystemInclude(DriverArgs, CC1Args, TargetDir.str());
+      break;
+    }
+    // Add generic path if nothing else succeeded so far.
     SmallString<128> Dir(SysRoot);
     llvm::sys::path::append(Dir, "include", "c++", "v1");
     addSystemInclude(DriverArgs, CC1Args, Dir.str());
     break;
   }
   case ToolChain::CST_Libstdcxx: {
     SmallString<128> Dir(SysRoot);
     llvm::sys::path::append(Dir, "include", "c++");
     std::error_code EC;
     Generic_GCC::GCCVersion Version = {"", -1, -1, -1, "", "", ""};
     // Walk the subdirs, and find the one with the newest gcc version:
-    for (llvm::vfs::directory_iterator
-             LI = getDriver().getVFS().dir_begin(Dir.str(), EC),
+    for (llvm::vfs::directory_iterator LI = D.getVFS().dir_begin(Dir.str(), EC),
                                        LE;
          !EC && LI != LE; LI = LI.increment(EC)) {
       StringRef VersionText = llvm::sys::path::filename(LI->path());
       auto CandidateVersion = Generic_GCC::GCCVersion::Parse(VersionText);
       if (CandidateVersion.Major == -1)
         continue;
       if (CandidateVersion <= Version)
         continue;
       Version = CandidateVersion;

clang/test/Driver/baremetal.cpp

 // CHECK-V6M-LIBCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-V6M-LIBCXX: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
 // CHECK-V6M-LIBCXX-SAME: "-L{{[^"]*}}{{[/\\]+}}Inputs{{[/\\]+}}baremetal_arm{{[/\\]+}}lib"
 // CHECK-V6M-LIBCXX-SAME: "-L[[RESOURCE_DIR]]{{[/\\]+}}lib{{[/\\]+}}baremetal"
 // CHECK-V6M-LIBCXX-SAME: "-lc++" "-lc++abi" "-lunwind"
 // CHECK-V6M-LIBCXX-SAME: "-lc" "-lm" "-lclang_rt.builtins-armv6m"
 // CHECK-V6M-LIBCXX-SAME: "-o" "{{.*}}.o"
 
+// RUN: rm -rf %T/baremetal_cxx_sysroot
+// RUN: mkdir -p %T/baremetal_cxx_sysroot/usr/include/c++/v1
+// RUN: %clangxx -no-canonical-prefixes %s -### -o %t.o 2>&1 \
+// RUN:     -target armv6m-none-eabi \
+// RUN:     --sysroot=%T/baremetal_cxx_sysroot \
+// RUN:     -stdlib=libc++ \
+// RUN:   | FileCheck --check-prefix=CHECK-V6M-LIBCXX-USR %s
+// CHECK-V6M-LIBCXX-USR: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
+// CHECK-V6M-LIBCXX-USR-NOT: "-internal-isystem" "{{[^"]+}}baremetal_cxx_sysroot{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}{{[^v].*}}"
+// CHECK-V6M-LIBCXX-USR-SAME: "-internal-isystem" "{{[^"]+}}baremetal_cxx_sysroot{{[/\\]+}}usr{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
+// CHECK-V6M-LIBCXX-USR: "{{[^"]*}}ld{{(\.(lld|bfd|gold))?}}{{(\.exe)?}}" "{{.*}}.o" "-Bstatic"
+// CHECK-V6M-LIBCXX-USR-SAME: "-L{{[^"]*}}{{[/\\]+}}baremetal_cxx_sysroot{{[/\\]+}}lib"
+// CHECK-V6M-LIBCXX-USR-SAME: "-L[[RESOURCE_DIR]]{{[/\\]+}}lib{{[/\\]+}}baremetal"
+// CHECK-V6M-LIBCXX-USR-SAME: "-lc++" "-lc++abi" "-lunwind"
+// CHECK-V6M-LIBCXX-USR-SAME: "-lc" "-lm" "-lclang_rt.builtins-armv6m"
+// CHECK-V6M-LIBCXX-USR-SAME: "-o" "{{.*}}.o"
+
 // RUN: %clangxx -no-canonical-prefixes %s -### -o %t.o 2>&1 \
 // RUN:     -target armv6m-none-eabi \
 // RUN:     --sysroot=%S/Inputs/baremetal_arm \
 // RUN:     -stdlib=libstdc++ \
 // RUN:   | FileCheck --check-prefix=CHECK-V6M-LIBSTDCXX %s
 // CHECK-V6M-LIBSTDCXX: "-resource-dir" "[[RESOURCE_DIR:[^"]+]]"
 // CHECK-V6M-LIBSTDCXX-NOT: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}v1"
 // CHECK-V6M-LIBSTDCXX-SAME: "-internal-isystem" "{{[^"]+}}{{[/\\]+}}include{{[/\\]+}}c++{{[/\\]+}}6.0.0"