Driver: implement driver automagic support for -lcc_kext

Rewrite linker arguments to use libclang_rt.cc_kext.a
instead of gcc-specific libcc_kext.a

Resolves Radar 7808495

llvm-svn: 114193

clang/include/clang/Driver/Options.td

@@ -749,3 +749,5 @@ def Z_Xlinker__no_demangle : Flag<"-Z-Xlinker-no-demangle">, Flags<[Unsupported,
 // Reserved library options.
 def Z_reserved_lib_stdcxx : Flag<"-Z-reserved-lib-stdc++">,
     Flags<[LinkerInput, NoArgumentUnused, Unsupported]>, Group<reserved_lib_Group>;
+def Z_reserved_lib_cckext : Flag<"-Z-reserved-lib-cckext">,
+    Flags<[LinkerInput, NoArgumentUnused, Unsupported]>, Group<reserved_lib_Group>;

clang/include/clang/Driver/ToolChain.h

@@ -177,6 +177,11 @@ public:
   /// for the given C++ standard library type.
   virtual void AddCXXStdlibLibArgs(const ArgList &Args,
                                    ArgStringList &CmdArgs) const;
+
+  /// AddCCKextLibArgs - Add the system specific linker arguments to use
+  /// for kernel extensions (Darwin-specific).
+  virtual void AddCCKextLibArgs(const ArgList &Args,
+                                ArgStringList &CmdArgs) const;
 };
 
 } // end namespace driver

clang/lib/Driver/Driver.cpp

@@ -158,15 +158,23 @@ DerivedArgList *Driver::TranslateInputArgs(const InputArgList &Args) const {
       continue;
     }
 
-    // Rewrite reserved library names, unless -nostdlib is present.
-    if (!HasNostdlib && A->getOption().matches(options::OPT_l)) {
+    // Rewrite reserved library names.
+    if (A->getOption().matches(options::OPT_l)) {
       llvm::StringRef Value = A->getValue(Args);
 
-      if (Value == "stdc++") {
+      // Rewrite unless -nostdlib is present.
+      if (!HasNostdlib && Value == "stdc++") {
         DAL->AddFlagArg(A, Opts->getOption(
                               options::OPT_Z_reserved_lib_stdcxx));
         continue;
       }
+
+      // Rewrite unconditionally.
+      if (Value == "cc_kext") {
+        DAL->AddFlagArg(A, Opts->getOption(
+                              options::OPT_Z_reserved_lib_cckext));
+        continue;
+      }
     }
 
     DAL->append(*it);

clang/lib/Driver/ToolChain.cpp

@@ -222,3 +222,8 @@ void ToolChain::AddCXXStdlibLibArgs(const ArgList &Args,
     break;
   }
 }
+
+void ToolChain::AddCCKextLibArgs(const ArgList &Args,
+                                 ArgStringList &CmdArgs) const {
+  CmdArgs.push_back("-lcc_kext");
+}

clang/lib/Driver/ToolChains.cpp

@@ -644,6 +644,27 @@ void DarwinClang::AddCXXStdlibLibArgs(const ArgList &Args,
   }
 }
 
+void DarwinClang::AddCCKextLibArgs(const ArgList &Args,
+                                   ArgStringList &CmdArgs) const {
+
+  // For Darwin platforms, use the compiler-rt-based support library
+  // instead of the gcc-provided one (which is also incidentally
+  // only present in the gcc lib dir, which makes it hard to find).
+
+  llvm::sys::Path P(getDriver().ResourceDir);
+  P.appendComponent("lib");
+  P.appendComponent("darwin");
+  P.appendComponent("libclang_rt.cc_kext.a");
+  
+  // For now, allow missing resource libraries to support developers who may
+  // not have compiler-rt checked out or integrated into their build.
+  if (!P.exists())
+    getDriver().Diag(clang::diag::warn_drv_missing_resource_library)
+      << P.str();
+  else
+    CmdArgs.push_back(Args.MakeArgString(P.str()));
+}
+
 DerivedArgList *Darwin::TranslateArgs(const DerivedArgList &Args,
                                       const char *BoundArch) const {
   DerivedArgList *DAL = new DerivedArgList(Args.getBaseArgs());

clang/lib/Driver/ToolChains.h

@@ -226,6 +226,9 @@ public:
   virtual void AddCXXStdlibLibArgs(const ArgList &Args,
                                    ArgStringList &CmdArgs) const;
 
+  virtual void AddCCKextLibArgs(const ArgList &Args,
+                                ArgStringList &CmdArgs) const;
+
   /// }
 };
 

clang/lib/Driver/Tools.cpp

@@ -116,6 +116,8 @@ static void AddLinkerInputs(const ToolChain &TC,
     // Handle reserved library options.
     if (A.getOption().matches(options::OPT_Z_reserved_lib_stdcxx)) {
       TC.AddCXXStdlibLibArgs(Args, CmdArgs);
+    } else if (A.getOption().matches(options::OPT_Z_reserved_lib_cckext)) {
+      TC.AddCCKextLibArgs(Args, CmdArgs);
     } else
       A.renderAsInput(Args, CmdArgs);
   }