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Introduce -nostdlib++ flag to disable linking the C++ standard library.

Browse Source 
Projects that want to statically link their own C++ standard library currently
need to pass -nostdlib or -nodefaultlibs, which also disables linking of the
builtins library, -lm, and so on. Alternatively, they could use `clang` instead
of `clang++`, but that already disables implicit addition of -lm on some
toolchains.

Add a dedicated flag -nostdlib++ that disables just linking of libc++ /
libstdc++. This is analogous to -nostdinc++.

https://reviews.llvm.org/D35780

llvm-svn: 308997
This commit is contained in:
Nico Weber 2017-07-25 18:02:57 +00:00
parent f5ecb5e1b4
commit 0ee47d92b2
23 changed files with 81 additions and 51 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
clang/include/clang/Driver/Options.td
View File

@ -2144,6 +2144,7 @@ def nostdlibinc : Flag<["-"], "nostdlibinc">;
def nostdincxx : Flag<["-"], "nostdinc++">, Flags<[CC1Option]>,
HelpText<"Disable standard #include directories for the C++ standard library">;
def nostdlib : Flag<["-"], "nostdlib">;
def nostdlibxx : Flag<["-"], "nostdlib++">;
def object : Flag<["-"], "object">;
def o : JoinedOrSeparate<["-"], "o">, Flags<[DriverOption, RenderAsInput, CC1Option, CC1AsOption]>,
HelpText<"Write output to <file>">, MetaVarName<"<file>">;

4
clang/include/clang/Driver/ToolChain.h
View File

@ -432,6 +432,10 @@ public:
AddClangCXXStdlibIncludeArgs(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;
/// AddCXXStdlibLibArgs - Add the system specific linker arguments to use
/// for the given C++ standard library type.
virtual void AddCXXStdlibLibArgs(const llvm::opt::ArgList &Args,

8
clang/lib/Driver/ToolChain.cpp
View File

@ -648,8 +648,16 @@ void ToolChain::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
DriverArgs.AddAllArgs(CC1Args, options::OPT_stdlib_EQ);
}
bool ToolChain::ShouldLinkCXXStdlib(const llvm::opt::ArgList &Args) const {
return getDriver().CCCIsCXX() &&
!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs,
options::OPT_nostdlibxx);
}
void ToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
ArgStringList &CmdArgs) const {
assert(!Args.hasArg(options::OPT_nostdlibxx) &&
"should not have called this");
CXXStdlibType Type = GetCXXStdlibType(Args);
switch (Type) {

7
clang/lib/Driver/ToolChains/Ananas.cpp
View File

@ -91,11 +91,10 @@ void ananas::Linker::ConstructJob(Compilation &C, const JobAction &JA,
AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (D.CCCIsCXX())
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (ToolChain.ShouldLinkCXXStdlib(Args))
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs))
CmdArgs.push_back("-lc");
}
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nostartfiles)) {
CmdArgs.push_back(Args.MakeArgString(ToolChain.GetFilePath("crtend.o")));

5
clang/lib/Driver/ToolChains/BareMetal.cpp
View File

@ -192,10 +192,9 @@ void baremetal::Linker::ConstructJob(Compilation &C, const JobAction &JA,
options::OPT_e, options::OPT_s, options::OPT_t,
options::OPT_Z_Flag, options::OPT_r});
if (TC.ShouldLinkCXXStdlib(Args))
TC.AddCXXStdlibLibArgs(Args, CmdArgs);
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (C.getDriver().CCCIsCXX())
TC.AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lc");
CmdArgs.push_back("-lm");

4
clang/lib/Driver/ToolChains/CloudABI.cpp
View File

@ -80,9 +80,9 @@ void cloudabi::Linker::ConstructJob(Compilation &C, const JobAction &JA,
AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
if (ToolChain.ShouldLinkCXXStdlib(Args))
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (D.CCCIsCXX())
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lc");
CmdArgs.push_back("-lcompiler_rt");
}

10
clang/lib/Driver/ToolChains/CommonArgs.cpp
View File

@ -600,10 +600,12 @@ collectSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
static void addLibFuzzerRuntime(const ToolChain &TC,
const ArgList &Args,
ArgStringList &CmdArgs) {
StringRef ParentDir = llvm::sys::path::parent_path(TC.getDriver().InstalledDir);
SmallString<128> P(ParentDir);
llvm::sys::path::append(P, "lib", "libLLVMFuzzer.a");
CmdArgs.push_back(Args.MakeArgString(P));
StringRef ParentDir =
llvm::sys::path::parent_path(TC.getDriver().InstalledDir);
SmallString<128> P(ParentDir);
llvm::sys::path::append(P, "lib", "libLLVMFuzzer.a");
CmdArgs.push_back(Args.MakeArgString(P));
if (!Args.hasArg(clang::driver::options::OPT_nostdlibxx))
TC.AddCXXStdlibLibArgs(Args, CmdArgs);
}

3
clang/lib/Driver/ToolChains/CrossWindows.cpp
View File

@ -160,8 +160,7 @@ void tools::CrossWindows::Linker::ConstructJob(
TC.AddFilePathLibArgs(Args, CmdArgs);
AddLinkerInputs(TC, Inputs, Args, CmdArgs, JA);
if (D.CCCIsCXX() && !Args.hasArg(options::OPT_nostdlib) &&
!Args.hasArg(options::OPT_nodefaultlibs)) {
if (TC.ShouldLinkCXXStdlib(Args)) {
bool StaticCXX = Args.hasArg(options::OPT_static_libstdcxx) &&
!Args.hasArg(options::OPT_static);
if (StaticCXX)

5
clang/lib/Driver/ToolChains/Darwin.cpp
View File

@ -549,10 +549,9 @@ void darwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
Args.MakeArgString(Twine("-threads=") + llvm::to_string(Parallelism)));
}
if (getToolChain().ShouldLinkCXXStdlib(Args))
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (getToolChain().getDriver().CCCIsCXX())
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
// link_ssp spec is empty.
// Let the tool chain choose which runtime library to link.

3
clang/lib/Driver/ToolChains/DragonFly.cpp
View File

@ -127,7 +127,8 @@ void dragonfly::Linker::ConstructJob(Compilation &C, const JobAction &JA,
}
if (D.CCCIsCXX()) {
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
if (getToolChain().ShouldLinkCXXStdlib(Args))
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lm");
}

3
clang/lib/Driver/ToolChains/FreeBSD.cpp
View File

@ -240,7 +240,8 @@ void freebsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
addOpenMPRuntime(CmdArgs, ToolChain, Args);
if (D.CCCIsCXX()) {
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (ToolChain.ShouldLinkCXXStdlib(Args))
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (Args.hasArg(options::OPT_pg))
CmdArgs.push_back("-lm_p");
else

16
clang/lib/Driver/ToolChains/Fuchsia.cpp
View File

@ -107,13 +107,15 @@ void fuchsia::Linker::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back("-Bdynamic");
if (D.CCCIsCXX()) {
bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
!Args.hasArg(options::OPT_static);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bstatic");
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bdynamic");
if (ToolChain.ShouldLinkCXXStdlib(Args)) {
bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
!Args.hasArg(options::OPT_static);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bstatic");
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bdynamic");
}
CmdArgs.push_back("-lm");
}

16
clang/lib/Driver/ToolChains/Gnu.cpp
View File

@ -560,13 +560,15 @@ void tools::gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (D.CCCIsCXX() &&
!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
!Args.hasArg(options::OPT_static);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bstatic");
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bdynamic");
if (ToolChain.ShouldLinkCXXStdlib(Args)) {
bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
!Args.hasArg(options::OPT_static);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bstatic");
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bdynamic");
}
CmdArgs.push_back("-lm");
}
// Silence warnings when linking C code with a C++ '-stdlib' argument.

3
clang/lib/Driver/ToolChains/Hexagon.cpp
View File

@ -248,7 +248,8 @@ constructHexagonLinkArgs(Compilation &C, const JobAction &JA,
//----------------------------------------------------------------------------
if (IncStdLib && IncDefLibs) {
if (D.CCCIsCXX()) {
HTC.AddCXXStdlibLibArgs(Args, CmdArgs);
if (HTC.ShouldLinkCXXStdlib(Args))
HTC.AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lm");
}

3
clang/lib/Driver/ToolChains/MinGW.cpp
View File

@ -185,8 +185,7 @@ void tools::MinGW::Linker::ConstructJob(Compilation &C, const JobAction &JA,
// TODO: Add profile stuff here
if (D.CCCIsCXX() &&
!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (TC.ShouldLinkCXXStdlib(Args)) {
bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
!Args.hasArg(options::OPT_static);
if (OnlyLibstdcxxStatic)

3
clang/lib/Driver/ToolChains/Minix.cpp
View File

@ -72,7 +72,8 @@ void tools::minix::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (D.CCCIsCXX()) {
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
if (getToolChain().ShouldLinkCXXStdlib(Args))
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lm");
}
}

16
clang/lib/Driver/ToolChains/NaCl.cpp
View File

@ -133,13 +133,15 @@ void nacltools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (D.CCCIsCXX() &&
!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
bool OnlyLibstdcxxStatic =
Args.hasArg(options::OPT_static_libstdcxx) && !IsStatic;
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bstatic");
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bdynamic");
if (ToolChain.ShouldLinkCXXStdlib(Args)) {
bool OnlyLibstdcxxStatic =
Args.hasArg(options::OPT_static_libstdcxx) && !IsStatic;
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bstatic");
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (OnlyLibstdcxxStatic)
CmdArgs.push_back("-Bdynamic");
}
CmdArgs.push_back("-lm");
}

3
clang/lib/Driver/ToolChains/NetBSD.cpp
View File

@ -278,7 +278,8 @@ void netbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
addOpenMPRuntime(CmdArgs, getToolChain(), Args);
if (D.CCCIsCXX()) {
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
if (getToolChain().ShouldLinkCXXStdlib(Args))
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lm");
}
if (NeedsSanitizerDeps)

3
clang/lib/Driver/ToolChains/OpenBSD.cpp
View File

@ -177,7 +177,8 @@ void openbsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (D.CCCIsCXX()) {
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
if (getToolChain().ShouldLinkCXXStdlib(Args))
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
if (Args.hasArg(options::OPT_pg))
CmdArgs.push_back("-lm_p");
else

3
clang/lib/Driver/ToolChains/PS4CPU.cpp
View File

@ -227,7 +227,8 @@ static void ConstructGoldLinkJob(const Tool &T, Compilation &C,
// libraries for both C and C++ compilations.
CmdArgs.push_back("-lkernel");
if (D.CCCIsCXX()) {
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (ToolChain.ShouldLinkCXXStdlib(Args))
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (Args.hasArg(options::OPT_pg))
CmdArgs.push_back("-lm_p");
else

2
clang/lib/Driver/ToolChains/Solaris.cpp
View File

@ -100,7 +100,7 @@ void solaris::Linker::ConstructJob(Compilation &C, const JobAction &JA,
AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (getToolChain().getDriver().CCCIsCXX())
if (getToolChain().ShouldLinkCXXStdlib(Args))
getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lgcc_s");
CmdArgs.push_back("-lc");

3
clang/lib/Driver/ToolChains/WebAssembly.cpp
View File

@ -38,7 +38,6 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
const char *LinkingOutput) const {
const ToolChain &ToolChain = getToolChain();
const Driver &D = ToolChain.getDriver();
const char *Linker = Args.MakeArgString(ToolChain.GetLinkerPath());
ArgStringList CmdArgs;
CmdArgs.push_back("-flavor");
@ -77,7 +76,7 @@ void wasm::Linker::ConstructJob(Compilation &C, const JobAction &JA,
AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs, JA);
if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
if (D.CCCIsCXX())
if (ToolChain.ShouldLinkCXXStdlib(Args))
ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
if (Args.hasArg(options::OPT_pthread))

8
clang/test/Driver/nostdlibxx.cpp Normal file
View File

@ -0,0 +1,8 @@
// RUN: %clangxx -target i686-pc-linux-gnu -### -nostdlib++ %s 2> %t
// RUN: FileCheck < %t %s
// We should still have -lm and the C standard libraries, but not -lstdc++.
// CHECK-NOT: -lstdc++
// CHECK-NOT: -lc++
// CHECK: -lm