[CMake] Add option to switch default C++ stdlib

With this option one can optionally override the architecture dependent
default library to use if no -stdlib= is provided on compiler invocation.

Differential Revision: http://reviews.llvm.org/D15920

llvm-svn: 260662

1 files changed, 11 insertions, 19 deletions

diff --git a/clang/lib/Driver/ToolChains.cpp b/clang/lib/Driver/ToolChains.cpp
index b8f55756aa5..a357863b8fa 100644
--- a/clang/lib/Driver/ToolChains.cpp
+++ b/clang/lib/Driver/ToolChains.cpp
@@ -65,6 +65,16 @@ types::ID MachO::LookupTypeForExtension(const char *Ext) const {
 
 bool MachO::HasNativeLLVMSupport() const { return true; }
 
+ToolChain::CXXStdlibType Darwin::GetDefaultCXXStdlibType() const {
+  // Default to use libc++ on OS X 10.9+ and iOS 7+.
+  if ((isTargetMacOS() && !isMacosxVersionLT(10, 9)) ||
+       (isTargetIOSBased() && !isIPhoneOSVersionLT(7, 0)) ||
+       isTargetWatchOSBased())
+    return ToolChain::CST_Libcxx;
+
+  return ToolChain::CST_Libstdcxx;
+}
+
 /// Darwin provides an ARC runtime starting in MacOS X 10.7 and iOS 5.0.
 ObjCRuntime Darwin::getDefaultObjCRuntime(bool isNonFragile) const {
   if (isTargetWatchOSBased())
@@ -1020,7 +1030,6 @@ DerivedArgList *Darwin::TranslateArgs(const DerivedArgList &Args,
                                       const char *BoundArch) const {
   // First get the generic Apple args, before moving onto Darwin-specific ones.
   DerivedArgList *DAL = MachO::TranslateArgs(Args, BoundArch);
-  const OptTable &Opts = getDriver().getOpts();
 
   // If no architecture is bound, none of the translations here are relevant.
   if (!BoundArch)
@@ -1051,14 +1060,6 @@ DerivedArgList *Darwin::TranslateArgs(const DerivedArgList &Args,
     }
   }
 
-  // Default to use libc++ on OS X 10.9+ and iOS 7+.
-  if (((isTargetMacOS() && !isMacosxVersionLT(10, 9)) ||
-       (isTargetIOSBased() && !isIPhoneOSVersionLT(7, 0)) ||
-       isTargetWatchOSBased()) &&
-      !Args.getLastArg(options::OPT_stdlib_EQ))
-    DAL->AddJoinedArg(nullptr, Opts.getOption(options::OPT_stdlib_EQ),
-                      "libc++");
-
   // Validate the C++ standard library choice.
   CXXStdlibType Type = GetCXXStdlibType(*DAL);
   if (Type == ToolChain::CST_Libcxx) {
@@ -3027,16 +3028,7 @@ Tool *Bitrig::buildAssembler() const {
 
 Tool *Bitrig::buildLinker() const { return new tools::bitrig::Linker(*this); }
 
-ToolChain::CXXStdlibType Bitrig::GetCXXStdlibType(const ArgList &Args) const {
-  if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
-    StringRef Value = A->getValue();
-    if (Value == "libstdc++")
-      return ToolChain::CST_Libstdcxx;
-    if (Value == "libc++")
-      return ToolChain::CST_Libcxx;
-
-    getDriver().Diag(diag::err_drv_invalid_stdlib_name) << A->getAsString(Args);
-  }
+ToolChain::CXXStdlibType Bitrig::GetDefaultCXXStdlibType() const {
   return ToolChain::CST_Libcxx;
 }