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

llvm-svn: 308997

1 files changed, 6 insertions, 4 deletions

diff --git a/clang/lib/Driver/ToolChains/CommonArgs.cpp b/clang/lib/Driver/ToolChains/CommonArgs.cpp
index 00bd60bc24b..aea36cd0eeb 100644
--- a/clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ b/clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -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);
 }