[clang] Don't include C++ Standard Library headers when -nostdinc is used

[ldionne]

Summary

This is a follow-up to 53c98d85a, which made the same change but only
for GNU. It seems that we should try to provide a consistent behavior
across all targets.

This fixes an issue where clang/test/Driver/nostdincxx.cpp would start
failing on non-GNU targets because that test was too loose in its checks.
It would only check that 'file not found' was part of the error message,
but didn't ensure that the file we had not found was <vector>.

[ldionne]

I'm not sure who else to add on this review. Since changing the behavior of user-facing flags can be breaking, I'm adding the vendors. Feel free to suggest more.

Note that this was discovered when landing D136683.

[mgorny]

I'd say this is fine to land as 16.x. I'll be doing another snapshot for Gentoo next weekend, so if it lands by then, we're going to do some crash testing.

[phosek]

LGTM

[ldionne]

Thanks! I'll land this and watch for any fallout.

clang/lib/Driver/ToolChains/Darwin.cpp

void DarwinClang::AddClangCXXStdlibIncludeArgs(
     llvm::opt::ArgStringList &CC1Args) const {
   // The implementation from a base class will pass through the -stdlib to
   // CC1Args.
   // FIXME: this should not be necessary, remove usages in the frontend
   //        (e.g. HeaderSearchOptions::UseLibcxx) and don't pipe -stdlib.
   //        Also check whether this is used for setting library search paths.
   ToolChain::AddClangCXXStdlibIncludeArgs(DriverArgs, CC1Args);
 
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
+  if (DriverArgs.hasArg(options::OPT_nostdinc, options::OPT_nostdlibinc,
+                        options::OPT_nostdincxx))
     return;
 
   llvm::SmallString<128> Sysroot = GetEffectiveSysroot(DriverArgs);
 
   switch (GetCXXStdlibType(DriverArgs)) {
   case ToolChain::CST_Libcxx: {
     // On Darwin, libc++ can be installed in one of the following two places:
     // 1. Alongside the compiler in         <install>/include/c++/v1

clang/lib/Driver/ToolChains/Fuchsia.cpp

if (!D.SysRoot.empty()) {
     SmallString<128> P(D.SysRoot);
     llvm::sys::path::append(P, "include");
     addExternCSystemInclude(DriverArgs, CC1Args, P.str());
   }
 }
 
 void Fuchsia::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                                            ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
+  if (DriverArgs.hasArg(options::OPT_nostdinc, options::OPT_nostdlibinc,
+                        options::OPT_nostdincxx))
     return;
 
   const Driver &D = getDriver();
   std::string Target = getTripleString();
 
   auto AddCXXIncludePath = [&](StringRef Path) {
     std::string Version = detectLibcxxVersion(Path);
     if (Version.empty())

clang/lib/Driver/ToolChains/MinGW.cpp

if (GuardArgs == "none") {
       getDriver().Diag(diag::err_drv_unsupported_option_argument)
           << A->getSpelling() << GuardArgs;
     }
   }
 }
 
 void toolchains::MinGW::AddClangCXXStdlibIncludeArgs(
     const ArgList &DriverArgs, ArgStringList &CC1Args) const {
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
+  if (DriverArgs.hasArg(options::OPT_nostdinc, options::OPT_nostdlibinc,
+                        options::OPT_nostdincxx))
     return;
 
   StringRef Slash = llvm::sys::path::get_separator();
 
   switch (GetCXXStdlibType(DriverArgs)) {
   case ToolChain::CST_Libcxx: {
     std::string TargetDir = (Base + "include" + Slash + getTripleString() +
                              Slash + "c++" + Slash + "v1")

clang/lib/Driver/ToolChains/WebAssembly.cpp

if (getTriple().getOS() != llvm::Triple::UnknownOS) {
     addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include/" + MultiarchTriple);
   }
   addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/include");
 }
 
 void WebAssembly::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
                                                ArgStringList &CC1Args) const {
 
-  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
-      DriverArgs.hasArg(options::OPT_nostdincxx))
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc, options::OPT_nostdinc,
+                        options::OPT_nostdincxx))
     return;
 
   switch (GetCXXStdlibType(DriverArgs)) {
   case ToolChain::CST_Libcxx:
     addLibCxxIncludePaths(DriverArgs, CC1Args);
     break;
   case ToolChain::CST_Libstdcxx:
     addLibStdCXXIncludePaths(DriverArgs, CC1Args);

clang/test/Driver/darwin-header-search-libcxx.cpp

 // RUN:   | FileCheck -DSYSROOT=%S/Inputs/basic_darwin_sdk_usr_cxx_v1 \
 // RUN:               -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain \
 // RUN:               --check-prefix=CHECK-LIBCXX-SYSROOT_AND_TOOLCHAIN-1 %s
 //
 // CHECK-LIBCXX-SYSROOT_AND_TOOLCHAIN-1: "-cc1"
 // CHECK-LIBCXX-SYSROOT_AND_TOOLCHAIN-1: "-internal-isystem" "[[TOOLCHAIN]]/usr/bin/../include/c++/v1"
 // CHECK-LIBCXX-SYSROOT_AND_TOOLCHAIN-1-NOT: "-internal-isystem" "[[SYSROOT]]/usr/include/c++/v1"
 
-// Make sure that using -nostdinc does not drop any C++ library include path.
-// This behavior is strange, but it is compatible with the legacy CC1 behavior.
-//
-// RUN: %clang -### %s -fsyntax-only 2>&1 \
-// RUN:     --target=x86_64-apple-darwin16 \
-// RUN:     -ccc-install-dir %S/Inputs/basic_darwin_toolchain/usr/bin \
-// RUN:     -resource-dir=%S/Inputs/resource_dir \
-// RUN:     -isysroot %S/Inputs/basic_darwin_sdk_usr_cxx_v1 \
-// RUN:     -stdlib=platform \
-// RUN:     -nostdinc \
-// RUN:   | FileCheck -DSYSROOT=%S/Inputs/basic_darwin_sdk_usr_cxx_v1 \
-// RUN:               -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain \
-// RUN:               --check-prefix=CHECK-LIBCXX-NOSTDINC-1 %s
-// CHECK-LIBCXX-NOSTDINC-1: "-cc1"
-// CHECK-LIBCXX-NOSTDINC-1-NOT: "-internal-isystem" "[[SYSROOT]]/usr/include/c++/v1"
-// CHECK-LIBCXX-NOSTDINC-1: "-internal-isystem" "[[TOOLCHAIN]]/usr/bin/../include/c++/v1"
+// Make sure that using -nostdinc, -nostdinc++ or -nostdlib will drop both the toolchain
+// C++ include path and the sysroot one.
 //
 // RUN: %clang -### %s -fsyntax-only 2>&1 \
 // RUN:     --target=x86_64-apple-darwin16 \
 // RUN:     -ccc-install-dir %S/Inputs/basic_darwin_toolchain/usr/bin \
 // RUN:     -resource-dir=%S/Inputs/resource_dir \
-// RUN:     -isysroot %S/Inputs/basic_darwin_sdk_no_libcxx \
+// RUN:     -isysroot %S/Inputs/basic_darwin_sdk_usr \
 // RUN:     -stdlib=platform \
 // RUN:     -nostdinc \
-// RUN:   | FileCheck -DSYSROOT=%S/Inputs/basic_darwin_sdk_no_libcxx \
+// RUN:   | FileCheck -DSYSROOT=%S/Inputs/basic_darwin_sdk_usr \
 // RUN:               -DTOOLCHAIN=%S/Inputs/basic_darwin_toolchain \
-// RUN:               --check-prefix=CHECK-LIBCXX-NOSTDINC-2 %s
-// CHECK-LIBCXX-NOSTDINC-2: "-cc1"
-// CHECK-LIBCXX-NOSTDINC-2: "-internal-isystem" "[[TOOLCHAIN]]/usr/bin/../include/c++/v1"
-// CHECK-LIBCXX-NOSTDINC-2-NOT: "-internal-isystem" "[[SYSROOT]]/usr/include/c++/v1"
-
-// Make sure that using -nostdinc++ or -nostdlib will drop both the toolchain
-// C++ include path and the sysroot one.
+// RUN:               --check-prefix=CHECK-LIBCXX-NOSTDLIBINC %s
+// CHECK-LIBCXX-NOSTDINC: "-cc1"
+// CHECK-LIBCXX-NOSTDINC-NOT: "-internal-isystem" "[[TOOLCHAIN]]/usr/bin/../include/c++/v1"
+// CHECK-LIBCXX-NOSTDINC-NOT: "-internal-isystem" "[[SYSROOT]]/usr/include/c++/v1"
 //
 // RUN: %clang -### %s -fsyntax-only 2>&1 \
 // RUN:     --target=x86_64-apple-darwin16 \
 // RUN:     -ccc-install-dir %S/Inputs/basic_darwin_toolchain/usr/bin \
 // RUN:     -resource-dir=%S/Inputs/resource_dir \
 // RUN:     -isysroot %S/Inputs/basic_darwin_sdk_usr_cxx_v1 \
 // RUN:     -stdlib=platform \
 // RUN:     -nostdinc++ \

clang/test/Driver/nostdincxx.cpp

 // RUN: not %clangxx -nostdinc %s 2>&1 | FileCheck %s
 // RUN: not %clangxx -nostdinc++ %s 2>&1 | FileCheck %s
 // RUN: not %clangxx -nostdlibinc %s 2>&1 | FileCheck %s
 // RUN: not %clangxx --target=x86_64-unknown-unknown-gnu -fsyntax-only -nostdinc -nostdinc++ %s 2>&1 | FileCheck /dev/null --implicit-check-not=-Wunused-command-line-argument
-// CHECK: file not found
-#include <vector> 
+// CHECK: 'vector' file not found
+#include <vector>
 
 // MSVC, PS4, PS5 have C++ headers in the same directory as C headers.
 // UNSUPPORTED: ms-sdk, ps4, ps5