smeenai created this revision.
smeenai added reviewers: compnerd, phosek, rsmith, zer0.
Herald added a subscriber: srhines.
Herald added a project: clang.
There are times when we wish to explicitly control the C++ standard
library search paths used by the driver. For example, when we're
building against the Android NDK, we might want to use the NDK's C++
headers (which have a custom inline namespace) even if we have C++
headers installed next to the driver. We might also be building against
a non-standard directory layout and wanting to specify the C++ standard
library include directories explicitly.
We could accomplish this by passing -nostdinc++ and adding an explicit
-isystem for our custom search directories. However, users of our
toolchain may themselves want to use -nostdinc++ and a custom C++ search
path (libc++'s build does this, for example), and our added -isystem
won't respect the -nostdinc++, leading to multiple C++ header
directories on the search path, which causes build failures.
Add a new driver option -stdlib++-isystem to support this use case.
Passing this option suppresses adding the default C++ library include
paths in the driver, and it also respects -nostdinc++ to allow users to
still override the C++ library paths themselves.
It's a bit unfortunate that we end up with both -stdlib++-isystem and
-cxx-isystem, but their semantics differ significantly. -cxx-isystem is
unaffected by -nostdinc++ and is added to the end of the search path
(which is not appropriate for C++ standard library headers, since they
often #include_next into other system headers), while -stdlib++-isystem
respects -nostdinc++, is added to the beginning of the search path, and
suppresses the default C++ library include paths.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D64089
Files:
clang/include/clang/Driver/Options.td
clang/include/clang/Driver/ToolChain.h
clang/lib/Driver/ToolChain.cpp
clang/lib/Driver/ToolChains/Clang.cpp
clang/test/Driver/stdlibxx-isystem.cpp
Index: clang/test/Driver/stdlibxx-isystem.cpp
===================================================================
--- /dev/null
+++ clang/test/Driver/stdlibxx-isystem.cpp
@@ -0,0 +1,48 @@
+// By default, we should search for libc++ next to the driver.
+// RUN: mkdir -p %t/bin
+// RUN: mkdir -p %t/include/c++/v1
+// RUN: %clang -target aarch64-linux-android -ccc-install-dir %t/bin \
+// RUN: -stdlib=libc++ -fsyntax-only %s -### 2>&1 | \
+// RUN: FileCheck -check-prefix=LIBCXX %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %t/bin \
+// RUN: -stdlib=libc++ -fsyntax-only %s -### 2>&1 | \
+// RUN: FileCheck -check-prefix=LIBCXX %s
+// LIBCXX: InstalledDir: [[INSTALLDIR:.+$]]
+// LIBCXX: "-internal-isystem" "[[INSTALLDIR]]/../include/c++/v1"
+
+// Passing -stdlib++-isystem should suppress the default search.
+// RUN: %clang -target aarch64-linux-android -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp/foo -stdlib++-isystem /tmp/bar -stdlib=libc++ \
+// RUN: -fsyntax-only %s -### 2>&1 | FileCheck -check-prefix=NODEFAULT %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp/foo -stdlib++-isystem /tmp/bar -stdlib=libc++ \
+// RUN: -fsyntax-only %s -### 2>&1 | FileCheck -check-prefix=NODEFAULT %s
+// NODEFAULT: InstalledDir: [[INSTALLDIR:.+$]]
+// NODEFAULT-NOT: "-internal-isystem" "[[INSTALLDIR]]/../include/c++/v1"
+
+// And we should add it as an -internal-isystem.
+// RUN: %clang -target aarch64-linux-android -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp/foo -stdlib++-isystem /tmp/bar -stdlib=libc++ \
+// RUN: -fsyntax-only %s -### 2>&1 | FileCheck -check-prefix=INCPATH %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp/foo -stdlib++-isystem /tmp/bar -stdlib=libc++ \
+// RUN: -fsyntax-only %s -### 2>&1 | FileCheck -check-prefix=INCPATH %s
+// INCPATH: "-internal-isystem" "/tmp/foo" "-internal-isystem" "/tmp/bar"
+
+// We shouldn't pass the -stdlib++-isystem to cc1.
+// RUN: %clang -target aarch64-linux-android -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp -stdlib=libc++ -fsyntax-only %s -### 2>&1 | \
+// RUN: FileCheck -check-prefix=NOCC1 %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp -stdlib=libc++ -fsyntax-only %s -### 2>&1 | \
+// RUN: FileCheck -check-prefix=NOCC1 %s
+// NOCC1-NOT: "-stdlib++-isystem" "/tmp"
+
+// It should respect -nostdinc++.
+// RUN: %clang -target aarch64-linux-android -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp/foo -stdlib++-isystem /tmp/bar -nostdinc++ \
+// RUN: -fsyntax-only %s -### 2>&1 | FileCheck -check-prefix=NOSTDINCXX %s
+// RUN: %clang -target x86_64-apple-darwin -ccc-install-dir %t/bin \
+// RUN: -stdlib++-isystem /tmp/foo -stdlib++-isystem /tmp/bar -nostdinc++ \
+// RUN: -fsyntax-only %s -### 2>&1 | FileCheck -check-prefix=NOSTDINCXX %s
+// NOSTDINCXX-NOT: "-internal-isystem" "/tmp/foo" "-internal-isystem" "/tmp/bar"
Index: clang/lib/Driver/ToolChains/Clang.cpp
===================================================================
--- clang/lib/Driver/ToolChains/Clang.cpp
+++ clang/lib/Driver/ToolChains/Clang.cpp
@@ -1241,6 +1241,9 @@
// Do not claim the argument so that the use of the argument does not
// silently go unnoticed on toolchains which do not honour the option.
continue;
+ } else if (A->getOption().matches(options::OPT_stdlibxx_isystem)) {
+ // Translated to -internal-isystem by the driver, no need to pass to cc1.
+ continue;
}
// Not translated, render as usual.
@@ -1295,11 +1298,15 @@
// of an offloading programming model.
// Add C++ include arguments, if needed.
- if (types::isCXX(Inputs[0].getType()))
- forAllAssociatedToolChains(C, JA, getToolChain(),
- [&Args, &CmdArgs](const ToolChain &TC) {
- TC.AddClangCXXStdlibIncludeArgs(Args, CmdArgs);
- });
+ if (types::isCXX(Inputs[0].getType())) {
+ bool HasStdlibxxIsystem = Args.hasArg(options::OPT_stdlibxx_isystem);
+ forAllAssociatedToolChains(
+ C, JA, getToolChain(),
+ [&Args, &CmdArgs, HasStdlibxxIsystem](const ToolChain &TC) {
+ HasStdlibxxIsystem ? TC.AddClangCXXStdlibIsystemArgs(Args, CmdArgs)
+ : TC.AddClangCXXStdlibIncludeArgs(Args, CmdArgs);
+ });
+ }
// Add system include arguments for all targets but IAMCU.
if (!IsIAMCU)
Index: clang/lib/Driver/ToolChain.cpp
===================================================================
--- clang/lib/Driver/ToolChain.cpp
+++ clang/lib/Driver/ToolChain.cpp
@@ -829,6 +829,16 @@
DriverArgs.AddAllArgs(CC1Args, options::OPT_stdlib_EQ);
}
+void ToolChain::AddClangCXXStdlibIsystemArgs(
+ const llvm::opt::ArgList &DriverArgs,
+ llvm::opt::ArgStringList &CC1Args) const {
+ DriverArgs.ClaimAllArgs(options::OPT_stdlibxx_isystem);
+ if (!DriverArgs.hasArg(options::OPT_nostdincxx))
+ for (const auto &P :
+ DriverArgs.getAllArgValues(options::OPT_stdlibxx_isystem))
+ addSystemInclude(DriverArgs, CC1Args, P);
+}
+
bool ToolChain::ShouldLinkCXXStdlib(const llvm::opt::ArgList &Args) const {
return getDriver().CCCIsCXX() &&
!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
Index: clang/include/clang/Driver/ToolChain.h
===================================================================
--- clang/include/clang/Driver/ToolChain.h
+++ clang/include/clang/Driver/ToolChain.h
@@ -542,6 +542,11 @@
AddClangCXXStdlibIncludeArgs(const llvm::opt::ArgList &DriverArgs,
llvm::opt::ArgStringList &CC1Args) const;
+ /// AddClangCXXStdlibIsystemArgs - Add the clang -cc1 level arguments to set
+ /// the specified include paths for the C++ standard library.
+ void AddClangCXXStdlibIsystemArgs(const llvm::opt::ArgList &DriverArgs,
+ llvm::opt::ArgStringList &CC1Args) const;
+
/// Returns if the C++ standard library should be linked in.
/// Note that e.g. -lm should still be linked even if this returns false.
bool ShouldLinkCXXStdlib(const llvm::opt::ArgList &Args) const;
Index: clang/include/clang/Driver/Options.td
===================================================================
--- clang/include/clang/Driver/Options.td
+++ clang/include/clang/Driver/Options.td
@@ -2627,6 +2627,10 @@
}]>;
def stdlib_EQ : Joined<["-", "--"], "stdlib=">, Flags<[CC1Option]>,
HelpText<"C++ standard library to use">, Values<"libc++,libstdc++,platform">;
+def stdlibxx_isystem : JoinedOrSeparate<["-"], "stdlib++-isystem">,
+ Group<clang_i_Group>,
+ HelpText<"Use directory as the C++ standard library include path">,
+ Flags<[DriverOption]>, MetaVarName<"<directory>">;
def unwindlib_EQ : Joined<["-", "--"], "unwindlib=">, Flags<[CC1Option]>,
HelpText<"Unwind library to use">, Values<"libgcc,unwindlib,platform">;
def sub__library : JoinedOrSeparate<["-"], "sub_library">;
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