[Clang][Driver] Add special-casing for including libc++ in C++03upstream/users/philnik777/add_libcxx03_include_strategy

9 files changed, 49 insertions, 4 deletions

diff --git a/clang/include/clang/Driver/ToolChain.h b/clang/include/clang/Driver/ToolChain.h
index c61cf2aa064e..f8329ae3fc39 100644
--- a/clang/include/clang/Driver/ToolChain.h
+++ b/clang/include/clang/Driver/ToolChain.h
@@ -738,6 +738,12 @@ public:
     // Whether to print a message if a checked directory isn't available.
     LLVM_PREFERRED_TYPE(bool)
     unsigned PrintDebugStatements : 1;
+
+  private:
+    LLVM_PREFERRED_TYPE(bool)
+    unsigned CheckCxx03 : 1;
+
+    friend class ToolChain;
   };
 
   /// Helper function to implement AddClangCXXStdlibIncludeArgs for libc++.
diff --git a/clang/lib/Driver/ToolChain.cpp b/clang/lib/Driver/ToolChain.cpp
index 42c9d6e91d3c..1e94a53f8a1d 100644
--- a/clang/lib/Driver/ToolChain.cpp
+++ b/clang/lib/Driver/ToolChain.cpp
@@ -1255,13 +1255,20 @@ bool ToolChain::AddLibcxxInclude(const llvm::opt::ArgList &DriverArgs,
                                  llvm::opt::ArgStringList &CC1Args,
                                  llvm::Twine IncludeRoot,
                                  IncludeStrategy Strategy) const {
+  using namespace std::literals;
+
   SmallString<128> Path;
   IncludeRoot.toVector(Path);
 
-  auto VersionDirName =
-      Strategy.Availability == IncludeStrategy::UseMaxVersionAvailable
-          ? detectLibcxxVersion(Path)
-          : "v1";
+  auto VersionDirName = [&] {
+    if (Strategy.CheckCxx03)
+      return "c++03"s;
+
+    if (Strategy.Availability == IncludeStrategy::UseMaxVersionAvailable)
+      return detectLibcxxVersion(Path);
+
+    return "v1"s;
+  }();
 
   if (VersionDirName.empty())
     return false;
@@ -1274,6 +1281,20 @@ bool ToolChain::AddLibcxxInclude(const llvm::opt::ArgList &DriverArgs,
       addSystemInclude(DriverArgs, CC1Args, TargetDir);
   }
 
+  if (const Arg *A =
+          DriverArgs.getLastArg(options::OPT_std_EQ, options::OPT_ansi);
+      !Strategy.CheckCxx03 &&
+      (A && (A->getOption().matches(options::OPT_ansi) ||
+             A->getValue() == "c++98"sv || A->getValue() == "c++03"sv ||
+             A->getValue() == "gnu++98"sv || A->getValue() == "gnu++03"sv))) {
+    auto StrategyCopy = Strategy;
+    StrategyCopy.AddTargetDirIfAvailable = false;
+    StrategyCopy.Availability = IncludeStrategy::CheckIfAvailable;
+    StrategyCopy.CheckCxx03 = true;
+    if (AddLibcxxInclude(DriverArgs, CC1Args, IncludeRoot, StrategyCopy))
+      return true;
+  }
+
   llvm::sys::path::append(Path, "c++", VersionDirName);
 
   if ((Strategy.Availability != IncludeStrategy::AssumeAvailable ||
diff --git a/clang/test/Driver/Inputs/basic_linux_libcxx_tree/usr/include/c++/c++03/.keep b/clang/test/Driver/Inputs/basic_linux_libcxx_tree/usr/include/c++/c++03/.keep
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_linux_libcxx_tree/usr/include/c++/c++03/.keep
diff --git a/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/bin/.keep b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/bin/.keep
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/bin/.keep
diff --git a/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/include/c++/v1/.keep b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/include/c++/v1/.keep
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/include/c++/v1/.keep
diff --git a/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/include/x86_64-unknown-linux-gnu/c++/v1/.keep b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/include/x86_64-unknown-linux-gnu/c++/v1/.keep
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/include/x86_64-unknown-linux-gnu/c++/v1/.keep
diff --git a/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/lib/.keep b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/lib/.keep
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/lib/.keep
diff --git a/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/lib/x86_64-unknown-linux-gnu/.keep b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/lib/x86_64-unknown-linux-gnu/.keep
new file mode 100644
index 000000000000..e69de29bb2d1
--- /dev/null
+++ b/clang/test/Driver/Inputs/basic_linux_libcxx_tree_no_cxx03/usr/lib/x86_64-unknown-linux-gnu/.keep
diff --git a/clang/test/Driver/linux-header-search.cpp b/clang/test/Driver/linux-header-search.cpp
index dd4d6eb483a3..0cce3e91e665 100644
--- a/clang/test/Driver/linux-header-search.cpp
+++ b/clang/test/Driver/linux-header-search.cpp
@@ -1,6 +1,24 @@
 // General tests that the header search paths detected by the driver and passed
 // to CC1 are sane.
 //
+
+// Test a simulated installation of libc++ in C++03 mode on Linux, both through sysroot and
+// the installation path of Clang.
+// RUN: %clang -### %s -fsyntax-only 2>&1 \
+// RUN:     --target=x86_64-unknown-linux-gnu \
+// RUN:     -stdlib=libc++ \
+// RUN:     -std=c++03 \
+// RUN:     -ccc-install-dir %S/Inputs/basic_linux_tree/usr/bin \
+// RUN:     -resource-dir=%S/Inputs/resource_dir \
+// RUN:     --sysroot=%S/Inputs/basic_linux_libcxx_tree \
+// RUN:     --gcc-toolchain="" \
+// RUN:   | FileCheck --check-prefix=CHECK-BASIC-LIBCXX-SYSROOT-CXX03 %s
+// CHECK-BASIC-LIBCXX-SYSROOT-CXX03: "-cc1"
+// CHECK-BASIC-LIBCXX-SYSROOT-CXX03: "-isysroot" "[[SYSROOT:[^"]+]]"
+// CHECK-BASIC-LIBCXX-SYSROOT-CXX03: "-internal-isystem" "[[SYSROOT]][[SEP:/|\\\\]]usr[[SEP]]include[[SEP]]x86_64-unknown-linux-gnu[[SEP]]c++[[SEP]]v1"
+// CHECK-BASIC-LIBCXX-SYSROOT-CXX03: "-internal-isystem" "[[SYSROOT]][[SEP]]usr[[SEP]]include[[SEP]]c++[[SEP]]c++03"
+// CHECK-BASIC-LIBCXX-SYSROOT-CXX03: "-internal-isystem" "[[SYSROOT]]/usr/local/include"
+
 // Test a simulated installation of libc++ on Linux, both through sysroot and
 // the installation path of Clang.
 // RUN: %clang -### %s -fsyntax-only 2>&1 \