[Driver] Warn on -nodefaultlibs and -fsanitize

[beanz]

Summary

The FreeBSD and GNUTools drivers support -fsanitize arguments bypassing -nodefaultlibs. With https://reviews.llvm.org/D24048, Darwin will support that behavior as well.

To make this a little less magical and behind the curtain this warning will fire when -nodefaultlibs is used with sanitizer arguments.

[bruno]

Hi Chris,

Thanks for doing this.

lib/Driver/Driver.cpp

1555

How hard is to fire the warning only when the target assumes this behavior? It seems misleading (and noisy) to warn when -nodefaultlibs isn't bypassed.

[beanz]

I can change the implementation, but that quickly falls into target specific driver code. It results in adding the warning in one place for Darwin, another for FreeBSD, and a third for GNUTools.

If that is the preferred way I can work up that patch.

[beanz]

Updates based on bruno's feedback.

[bruno]

include/clang/Basic/DiagnosticDriverKinds.td

276

What about something like: "-nodefaultlibs does not skip sanitizer runtime libs when used with -fsanitize." ?

[beanz]

• Changed warning text based on feedback from bruno
• Made the warning apply to -nostdlib as well as -nodefaultlibs based on offline discussion with Anna

include/clang/Basic/DiagnosticDriverKinds.td

def warn_drv_ps4_force_pic : Warning<
   "option '%0' was ignored by the PS4 toolchain, using '-fPIC'">,
   InGroup<OptionIgnored>;
 
 def warn_drv_ps4_sdk_dir : Warning<
   "environment variable SCE_ORBIS_SDK_DIR is set, but points to invalid or nonexistent directory '%0'">,
   InGroup<InvalidOrNonExistentDirectory>;
 
 def err_drv_unsupported_linker : Error<"unsupported value '%0' for -linker option">;
+
+def warn_drv_sanitizers_and_nodefaultlibs : Warning<
+  "-nodefaultlibs and -nostdlib do not skip sanitizer runtime libs when used with -fsanitize.">,
+  InGroup<DiagGroup<"unexpected-driver-behavior">>;
 }

include/clang/Driver/SanitizerArgs.h

public:
   }
   bool needsCfiRt() const;
   bool needsCfiDiagRt() const;
   bool needsStatsRt() const { return Stats; }
   bool needsEsanRt() const {
     return Sanitizers.hasOneOf(SanitizerKind::Efficiency);
   }
 
+  bool hasSanitizers() const { return !Sanitizers.empty(); }
+
   bool requiresPIE() const;
   bool needsUnwindTables() const;
   bool linkCXXRuntimes() const { return LinkCXXRuntimes; }
   bool hasCrossDsoCfi() const { return CfiCrossDso; }
   void addArgs(const ToolChain &TC, const llvm::opt::ArgList &Args,
                llvm::opt::ArgStringList &CmdArgs, types::ID InputType) const;
 };
 
 }  // namespace driver
 }  // namespace clang
 
 #endif

lib/Driver/Driver.cpp

void Driver::BuildActions(Compilation &C, DerivedArgList &Args,
   if (!SuppressMissingInputWarning && Inputs.empty()) {
     Diag(clang::diag::err_drv_no_input_files);
     return;
   }
 
   Arg *FinalPhaseArg;
   phases::ID FinalPhase = getFinalPhase(Args, &FinalPhaseArg);
 
-  if (FinalPhase == phases::Link && Args.hasArg(options::OPT_emit_llvm)) {
+  if (FinalPhase == phases::Link && Args.hasArg(options::OPT_emit_llvm))
     Diag(clang::diag::err_drv_emit_llvm_link);
-  }
 
   // Reject -Z* at the top level, these options should never have been exposed
   // by gcc.
   if (Arg *A = Args.getLastArg(options::OPT_Z_Joined))
     Diag(clang::diag::err_drv_use_of_Z_option) << A->getAsString(Args);
 
   // Diagnose misuse of /Fo.
   if (Arg *A = Args.getLastArg(options::OPT__SLASH_Fo)) {
     StringRef V = A->getValue();
     if (Inputs.size() > 1 && !V.empty() &&
         !llvm::sys::path::is_separator(V.back())) {
       // Check whether /Fo tries to name an output file for multiple inputs.
       Diag(clang::diag::err_drv_out_file_argument_with_multiple_sources)

lib/Driver/ToolChains.cpp

if (AddRPath) {
     CmdArgs.push_back("-rpath");
     CmdArgs.push_back("@executable_path");
 
     // Add the path to the resource dir to rpath to support using the dylib
     // from the default location without copying.
     CmdArgs.push_back("-rpath");
     CmdArgs.push_back(Args.MakeArgString(Dir));
   }
+  if (Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs))
+    getDriver().Diag(clang::diag::warn_drv_sanitizers_and_nodefaultlibs);
 }
 
 StringRef Darwin::getPlatformFamily() const {
   switch (TargetPlatform) {
     case DarwinPlatformKind::MacOS:
       return "MacOSX";
     case DarwinPlatformKind::IPhoneOS:
     case DarwinPlatformKind::IPhoneOSSimulator:

lib/Driver/Tools.cpp

void freebsd::Linker::ConstructJob(Compilation &C, const JobAction &JA,
   Args.AddAllArgs(CmdArgs, options::OPT_t);
   Args.AddAllArgs(CmdArgs, options::OPT_Z_Flag);
   Args.AddAllArgs(CmdArgs, options::OPT_r);
 
   if (D.isUsingLTO())
     AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin);
 
   bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
+
+  if (NeedsSanitizerDeps &&
+      Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs))
+    D.Diag(clang::diag::warn_drv_sanitizers_and_nodefaultlibs);
   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
 
   if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
     addOpenMPRuntime(CmdArgs, ToolChain, Args);
     if (D.CCCIsCXX()) {
       ToolChain.AddCXXStdlibLibArgs(Args, CmdArgs);
       if (Args.hasArg(options::OPT_pg))
         CmdArgs.push_back("-lm_p");
void gnutools::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   if (D.isUsingLTO())
     AddGoldPlugin(ToolChain, Args, CmdArgs, D.getLTOMode() == LTOK_Thin);
 
   if (Args.hasArg(options::OPT_Z_Xlinker__no_demangle))
     CmdArgs.push_back("--no-demangle");
 
   bool NeedsSanitizerDeps = addSanitizerRuntimes(ToolChain, Args, CmdArgs);
+
+  if (NeedsSanitizerDeps &&
+      Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs))
+    D.Diag(clang::diag::warn_drv_sanitizers_and_nodefaultlibs);
+
   bool NeedsXRayDeps = addXRayRuntime(ToolChain, Args, CmdArgs);
   AddLinkerInputs(ToolChain, Inputs, Args, CmdArgs);
   // The profile runtime also needs access to system libraries.
   getToolChain().addProfileRTLibs(Args, CmdArgs);
 
   if (D.CCCIsCXX() &&
       !Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
     bool OnlyLibstdcxxStatic = Args.hasArg(options::OPT_static_libstdcxx) &&

test/Driver/nodefaultlib.c

 // RUN: %clang -target i686-pc-linux-gnu -### -nodefaultlibs %s 2>&1 | FileCheck -check-prefix=TEST1 %s
 // TEST1-NOT: start-group
 // TEST1-NOT: "-lgcc"
 // TEST1-NOT: "-lc"
 // TEST1: crtbegin
 // TEST1: crtend
 
 // RUN: %clang -target i686-pc-linux-gnu -stdlib=libc++ -nodefaultlibs -lstdc++ -### %s 2>&1 | FileCheck -check-prefix=TEST2 %s
 // TEST2-NOT: "-lc++"
 // TEST2: "-lstdc++"
+
+// RUN: %clang -target i686-pc-linux-gnu -nodefaultlibs -fsanitize=address -### %s 2>&1 | FileCheck -check-prefix=TEST3 %s
+// RUN: %clang -target i686-unknown-freebsd -nodefaultlibs -fsanitize=address -### %s 2>&1 | FileCheck -check-prefix=TEST3 %s
+// TEST3: warning: -nodefaultlibs and -nostdlib do not skip sanitizer runtime libs when used with -fsanitize.
+// TEST3: libclang_rt.asan-i686.a
+
+// RUN: %clang -target i686-apple-darwin -nodefaultlibs -fsanitize=address -### %s 2>&1 | FileCheck -check-prefix=TEST4 %s
+// TEST4: warning: -nodefaultlibs and -nostdlib do not skip sanitizer runtime libs when used with -fsanitize.
+// TEST4: libclang_rt.asan_osx_dynamic.dylib

test/Driver/nostdlib.c

 //
 // RUN: %clang -target x86_64-pc-windows-msvc -nostdlib --rtlib=compiler-rt -### %s 2>&1 | FileCheck %s -check-prefix CHECK-MSVC-NOSTDLIB
 // RUN: %clang -target x86_64-pc-windows-msvc --rtlib=compiler-rt -nostdlib -### %s 2>&1 | FileCheck %s -check-prefix CHECK-MSVC-NOSTDLIB
 //
 // CHECK-LINUX-NOSTDLIB: warning: argument unused during compilation: '--rtlib=compiler-rt'
 // CHECK-LINUX-NOSTDLIB: "{{(.*[^.0-9A-Z_a-z])?}}ld{{(.exe)?}}"
 // CHECK-LINUX-NOSTDLIB-NOT: "{{.*}}/Inputs/resource_dir{{/|\\\\}}lib{{/|\\\\}}linux{{/|\\\\}}libclang_rt.builtins-i686.a"
 // CHECK-MSVC-NOSTDLIB: warning: argument unused during compilation: '--rtlib=compiler-rt'
+
+// RUN: %clang -target i686-pc-linux-gnu -nostdlib -fsanitize=address -### %s 2>&1 | FileCheck -check-prefix=TEST3 %s
+// RUN: %clang -target i686-unknown-freebsd -nodefaultlibs -fsanitize=address -### %s 2>&1 | FileCheck -check-prefix=TEST3 %s
+// TEST3: warning: -nodefaultlibs and -nostdlib do not skip sanitizer runtime libs when used with -fsanitize.
+// TEST3: libclang_rt.asan-i686.a
+
+// RUN: %clang -target i686-apple-darwin -nostdlib -fsanitize=address -### %s 2>&1 | FileCheck -check-prefix=TEST4 %s
+// TEST4: warning: -nodefaultlibs and -nostdlib do not skip sanitizer runtime libs when used with -fsanitize.
+// TEST4: libclang_rt.asan_osx_dynamic.dylib