Teach `-fsanitize=fuzzer` to respect `-static` and `-static-libstdc++` when adding C++ standard libraries.

[chandlerc]

Summary

Makes linking the sanitizers follow the same logic as the rest of the
driver with respect to the static linking strategy for the C++ standard
library.

[MaskRay]

clang/lib/Driver/ToolChains/CommonArgs.cpp

840

This is correct. If GNU ld<2.25 compatibility is not needed, --push-state, -Bstatic, link, --pop-state

[chandlerc]

Ping (and adding some sanitizer folks)? I'd really love to stop building with this local patch....

clang/lib/Driver/ToolChains/CommonArgs.cpp

840

I'd prefer to keep this as-is because it matches exactly what the toolchain does elsewhere. If we want to drop support for older lds, we should update in both places.

[vitalybuka]

LGTM, but it could be better with a test

[chandlerc]

Update with a regression test.

[chandlerc]

In D80488#2341009, @vitalybuka wrote:

LGTM, but it could be better with a test

Thanks, added test and landing.

clang/lib/Driver/ToolChains/CommonArgs.cpp

bool tools::addSanitizerRuntimes(const ToolChain &TC, const ArgList &Args,
   // Inject libfuzzer dependencies.
   if (SanArgs.needsFuzzer() && SanArgs.linkRuntimes() &&
       !Args.hasArg(options::OPT_shared)) {
 
     addSanitizerRuntime(TC, Args, CmdArgs, "fuzzer", false, true);
     if (SanArgs.needsFuzzerInterceptors())
       addSanitizerRuntime(TC, Args, CmdArgs, "fuzzer_interceptors", false,
                           true);
-    if (!Args.hasArg(clang::driver::options::OPT_nostdlibxx))
+    if (!Args.hasArg(clang::driver::options::OPT_nostdlibxx)) {
+      bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&
+                                 !Args.hasArg(options::OPT_static);
+      if (OnlyLibstdcxxStatic)
+        CmdArgs.push_back("-Bstatic");
       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
+      if (OnlyLibstdcxxStatic)
+        CmdArgs.push_back("-Bdynamic");
+    }
   }
 
   for (auto RT : SharedRuntimes)
     addSanitizerRuntime(TC, Args, CmdArgs, RT, true, false);
   for (auto RT : HelperStaticRuntimes)
     addSanitizerRuntime(TC, Args, CmdArgs, RT, false, true);
   bool AddExportDynamic = false;
   for (auto RT : StaticRuntimes) {

clang/test/Driver/fuzzer.c

 // Check that we don't link in libFuzzer when compiling with -fsanitize=fuzzer-no-link.
 // RUN: %clang -fsanitize=fuzzer-no-link %s -target x86_64-apple-darwin14 -### 2>&1 | FileCheck --check-prefixes=CHECK-NOLIB,CHECK-COV %s
 // CHECK-NOLIB-NOT: libclang_rt.libfuzzer
 // CHECK-COV: -fsanitize-coverage-inline-8bit-counters
 
 // RUN: %clang -fsanitize=fuzzer -fsanitize-coverage=trace-pc %s -### 2>&1 | FileCheck --check-prefixes=CHECK-MSG %s
 // CHECK-MSG-NOT: argument unused during compilation
 
+// Check that we respect whether thes tandard library should be linked
+// statically.
+//
+// RUN: %clang -fsanitize=fuzzer -target i386-unknown-linux -stdlib=libstdc++ %s -### 2>&1 | FileCheck --check-prefixes=CHECK-LIBSTDCXX-DYNAMIC %s
+// CHECK-LIBSTDCXX-DYNAMIC-NOT: -Bstatic
+// CHECK-LIBSTDCXX-DYNAMIC: -lstdc++
+//
+// RUN: %clang -fsanitize=fuzzer -target i386-unknown-linux -stdlib=libstdc++ -static-libstdc++ %s -### 2>&1 | FileCheck --check-prefixes=CHECK-LIBSTDCXX-STATIC %s
+// CHECK-LIBSTDCXX-STATIC: "-Bstatic" "-lstdc++"
+//
+// RUN: %clang -fsanitize=fuzzer -target i386-unknown-linux -stdlib=libc++ %s -### 2>&1 | FileCheck --check-prefixes=CHECK-LIBCXX-DYNAMIC %s
+// CHECK-LIBCXX-DYNAMIC-NOT: -Bstatic
+// CHECK-LIBCXX-DYNAMIC: -lc++
+//
+// RUN: %clang -fsanitize=fuzzer -target i386-unknown-linux -stdlib=libc++ -static-libstdc++ %s -### 2>&1 | FileCheck --check-prefixes=CHECK-LIBCXX-STATIC %s
+// CHECK-LIBCXX-STATIC: "-Bstatic" "-lc++"
+
 int LLVMFuzzerTestOneInput(const char *Data, long Size) {
   return 0;
 }