Introduce -nostdlib++ flag to disable linking the C++ standard library.
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
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@308997 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/clang/Driver/Options.td b/include/clang/Driver/Options.td
index 6c51976..0e3d19a 100644
--- a/include/clang/Driver/Options.td
+++ b/include/clang/Driver/Options.td
@@ -2109,6 +2109,7 @@
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>">;
diff --git a/include/clang/Driver/ToolChain.h b/include/clang/Driver/ToolChain.h
index 105d0f3..d3e72d7 100644
--- a/include/clang/Driver/ToolChain.h
+++ b/include/clang/Driver/ToolChain.h
@@ -431,6 +431,10 @@
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,
diff --git a/lib/Driver/ToolChain.cpp b/lib/Driver/ToolChain.cpp
index 4f82503..5f4cc67 100644
--- a/lib/Driver/ToolChain.cpp
+++ b/lib/Driver/ToolChain.cpp
@@ -648,8 +648,16 @@
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) {
diff --git a/lib/Driver/ToolChains/Ananas.cpp b/lib/Driver/ToolChains/Ananas.cpp
index a67e1d2..ee072cc 100644
--- a/lib/Driver/ToolChains/Ananas.cpp
+++ b/lib/Driver/ToolChains/Ananas.cpp
@@ -91,11 +91,10 @@
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")));
diff --git a/lib/Driver/ToolChains/BareMetal.cpp b/lib/Driver/ToolChains/BareMetal.cpp
index 66246f6..89593d4 100644
--- a/lib/Driver/ToolChains/BareMetal.cpp
+++ b/lib/Driver/ToolChains/BareMetal.cpp
@@ -191,10 +191,9 @@
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");
diff --git a/lib/Driver/ToolChains/CloudABI.cpp b/lib/Driver/ToolChains/CloudABI.cpp
index 0f6c712..cdf807f 100644
--- a/lib/Driver/ToolChains/CloudABI.cpp
+++ b/lib/Driver/ToolChains/CloudABI.cpp
@@ -80,9 +80,9 @@
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");
}
diff --git a/lib/Driver/ToolChains/CommonArgs.cpp b/lib/Driver/ToolChains/CommonArgs.cpp
index 5e360f6..2fdd3df 100644
--- a/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/lib/Driver/ToolChains/CommonArgs.cpp
@@ -580,10 +580,12 @@
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);
}
diff --git a/lib/Driver/ToolChains/CrossWindows.cpp b/lib/Driver/ToolChains/CrossWindows.cpp
index d290c62..c2ee0f7 100644
--- a/lib/Driver/ToolChains/CrossWindows.cpp
+++ b/lib/Driver/ToolChains/CrossWindows.cpp
@@ -160,8 +160,7 @@
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)
diff --git a/lib/Driver/ToolChains/Darwin.cpp b/lib/Driver/ToolChains/Darwin.cpp
index e41b50c..af1b491 100644
--- a/lib/Driver/ToolChains/Darwin.cpp
+++ b/lib/Driver/ToolChains/Darwin.cpp
@@ -548,10 +548,9 @@
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.
diff --git a/lib/Driver/ToolChains/DragonFly.cpp b/lib/Driver/ToolChains/DragonFly.cpp
index bd2c7fc..648469e 100644
--- a/lib/Driver/ToolChains/DragonFly.cpp
+++ b/lib/Driver/ToolChains/DragonFly.cpp
@@ -127,7 +127,8 @@
}
if (D.CCCIsCXX()) {
- getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
+ if (getToolChain().ShouldLinkCXXStdlib(Args))
+ getToolChain().AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lm");
}
diff --git a/lib/Driver/ToolChains/FreeBSD.cpp b/lib/Driver/ToolChains/FreeBSD.cpp
index c6626e9..2f066cf 100644
--- a/lib/Driver/ToolChains/FreeBSD.cpp
+++ b/lib/Driver/ToolChains/FreeBSD.cpp
@@ -240,7 +240,8 @@
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
diff --git a/lib/Driver/ToolChains/Fuchsia.cpp b/lib/Driver/ToolChains/Fuchsia.cpp
index b8757cf..2111951 100644
--- a/lib/Driver/ToolChains/Fuchsia.cpp
+++ b/lib/Driver/ToolChains/Fuchsia.cpp
@@ -104,13 +104,15 @@
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");
}
diff --git a/lib/Driver/ToolChains/Gnu.cpp b/lib/Driver/ToolChains/Gnu.cpp
index d50f8e2..c1f0523 100644
--- a/lib/Driver/ToolChains/Gnu.cpp
+++ b/lib/Driver/ToolChains/Gnu.cpp
@@ -560,13 +560,15 @@
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.
diff --git a/lib/Driver/ToolChains/Hexagon.cpp b/lib/Driver/ToolChains/Hexagon.cpp
index 1d7bcf8..dd79414 100644
--- a/lib/Driver/ToolChains/Hexagon.cpp
+++ b/lib/Driver/ToolChains/Hexagon.cpp
@@ -248,7 +248,8 @@
//----------------------------------------------------------------------------
if (IncStdLib && IncDefLibs) {
if (D.CCCIsCXX()) {
- HTC.AddCXXStdlibLibArgs(Args, CmdArgs);
+ if (HTC.ShouldLinkCXXStdlib(Args))
+ HTC.AddCXXStdlibLibArgs(Args, CmdArgs);
CmdArgs.push_back("-lm");
}
diff --git a/lib/Driver/ToolChains/MinGW.cpp b/lib/Driver/ToolChains/MinGW.cpp
index 7550bab..1c5eeb3 100644
--- a/lib/Driver/ToolChains/MinGW.cpp
+++ b/lib/Driver/ToolChains/MinGW.cpp
@@ -185,8 +185,7 @@
// 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)
diff --git a/lib/Driver/ToolChains/Minix.cpp b/lib/Driver/ToolChains/Minix.cpp
index 2e8939c..39e6f90 100644
--- a/lib/Driver/ToolChains/Minix.cpp
+++ b/lib/Driver/ToolChains/Minix.cpp
@@ -72,7 +72,8 @@
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");
}
}
diff --git a/lib/Driver/ToolChains/NaCl.cpp b/lib/Driver/ToolChains/NaCl.cpp
index 5eb5c74..128478d 100644
--- a/lib/Driver/ToolChains/NaCl.cpp
+++ b/lib/Driver/ToolChains/NaCl.cpp
@@ -133,13 +133,15 @@
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");
}
diff --git a/lib/Driver/ToolChains/NetBSD.cpp b/lib/Driver/ToolChains/NetBSD.cpp
index d7d3ad6..dcd820f 100644
--- a/lib/Driver/ToolChains/NetBSD.cpp
+++ b/lib/Driver/ToolChains/NetBSD.cpp
@@ -276,7 +276,8 @@
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 (Args.hasArg(options::OPT_pthread))
diff --git a/lib/Driver/ToolChains/OpenBSD.cpp b/lib/Driver/ToolChains/OpenBSD.cpp
index c5f266e..7b77784 100644
--- a/lib/Driver/ToolChains/OpenBSD.cpp
+++ b/lib/Driver/ToolChains/OpenBSD.cpp
@@ -177,7 +177,8 @@
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
diff --git a/lib/Driver/ToolChains/PS4CPU.cpp b/lib/Driver/ToolChains/PS4CPU.cpp
index c1b8c3d..b37fe7d 100644
--- a/lib/Driver/ToolChains/PS4CPU.cpp
+++ b/lib/Driver/ToolChains/PS4CPU.cpp
@@ -227,7 +227,8 @@
// 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
diff --git a/lib/Driver/ToolChains/Solaris.cpp b/lib/Driver/ToolChains/Solaris.cpp
index 78797c4..a58db3e 100644
--- a/lib/Driver/ToolChains/Solaris.cpp
+++ b/lib/Driver/ToolChains/Solaris.cpp
@@ -100,7 +100,7 @@
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");
diff --git a/lib/Driver/ToolChains/WebAssembly.cpp b/lib/Driver/ToolChains/WebAssembly.cpp
index 3471569..852b3b9 100644
--- a/lib/Driver/ToolChains/WebAssembly.cpp
+++ b/lib/Driver/ToolChains/WebAssembly.cpp
@@ -38,7 +38,6 @@
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 @@
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))
diff --git a/test/Driver/nostdlibxx.cpp b/test/Driver/nostdlibxx.cpp
new file mode 100644
index 0000000..02bd62d
--- /dev/null
+++ b/test/Driver/nostdlibxx.cpp
@@ -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
