From 52b42bace1338f8146d7dd5d1a7f6e41d5f5f80d Mon Sep 17 00:00:00 2001
From: David Chisnall <theraven@FreeBSD.org>
Date: Fri, 6 Sep 2013 20:08:03 +0000
Subject: [PATCH] On platforms where clang is the default compiler, don't build
 gcc or libstdc++. To enable them, set WITH_GCC and WITH_GNUCXX in src.conf.
 Make clang default to using libc++ on FreeBSD 10. Bumped __FreeBSD_version
 for the change.

GCC is still enabled on PC98, because the PC98 bootloader requires GCC to build
(or, at least, hard-codes the use of gcc into its build).

Thanks to everyone who helped make the ports tree ready for this (and bapt
for coordinating them all).  Also to imp for reviewing this and working on the
forward-porting of the changes in our gcc so that we're getting to a much
better place with regard to external toolchains.

Sorry to all of the people who helped who I forgot to mention by name.

Reviewed by:	bapt, imp, dim, ...
---
 .../tools/clang/lib/Driver/ToolChains.cpp     | 32 +++++++++++++++++++
 .../llvm/tools/clang/lib/Driver/ToolChains.h  |  5 +++
 gnu/lib/Makefile                              |  2 +-
 gnu/usr.bin/cc/Makefile                       |  7 +++-
 share/mk/bsd.own.mk                           | 28 +++++++++++++++-
 sys/sys/param.h                               |  2 +-
 tools/build/options/WITHOUT_GNUCXX            |  3 ++
 tools/build/options/WITH_GNUCXX               |  3 ++
 8 files changed, 78 insertions(+), 4 deletions(-)
 create mode 100644 tools/build/options/WITHOUT_GNUCXX
 create mode 100644 tools/build/options/WITH_GNUCXX

diff --git a/contrib/llvm/tools/clang/lib/Driver/ToolChains.cpp b/contrib/llvm/tools/clang/lib/Driver/ToolChains.cpp
index fffba0e4e50f..d8d580b8b5cc 100644
--- a/contrib/llvm/tools/clang/lib/Driver/ToolChains.cpp
+++ b/contrib/llvm/tools/clang/lib/Driver/ToolChains.cpp
@@ -1851,6 +1851,38 @@ bool FreeBSD::UseSjLjExceptions() const {
   }
 }
 
+ToolChain::CXXStdlibType
+FreeBSD::GetCXXStdlibType(const ArgList &Args) const {
+  if (Arg *A = Args.getLastArg(options::OPT_stdlib_EQ)) {
+    StringRef Value = A->getValue();
+    if (Value == "libc++")
+      return ToolChain::CST_Libcxx;
+    if (Value == "libstdc++")
+      return ToolChain::CST_Libstdcxx;
+    getDriver().Diag(diag::err_drv_invalid_stdlib_name)
+      << A->getAsString(Args);
+  }
+
+  return getTriple().getOSMajorVersion() >= 10 ? ToolChain::CST_Libcxx :
+         ToolChain::CST_Libstdcxx;
+}
+
+void FreeBSD::AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                          ArgStringList &CC1Args) const {
+  if (DriverArgs.hasArg(options::OPT_nostdlibinc) ||
+      DriverArgs.hasArg(options::OPT_nostdincxx))
+    return;
+
+  if (GetCXXStdlibType(DriverArgs) == ToolChain::CST_Libcxx)
+    addSystemInclude(DriverArgs, CC1Args,
+                     getDriver().SysRoot + "/usr/include/c++/v1");
+  else
+    addSystemInclude(DriverArgs, CC1Args,
+                     getDriver().SysRoot + "/usr/include/c++/4.2");
+  return;
+
+}
+
 /// NetBSD - NetBSD tool chain which can call as(1) and ld(1) directly.
 
 NetBSD::NetBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args)
diff --git a/contrib/llvm/tools/clang/lib/Driver/ToolChains.h b/contrib/llvm/tools/clang/lib/Driver/ToolChains.h
index 3afd8dd228b6..2b140c1cd0a3 100644
--- a/contrib/llvm/tools/clang/lib/Driver/ToolChains.h
+++ b/contrib/llvm/tools/clang/lib/Driver/ToolChains.h
@@ -458,9 +458,14 @@ class LLVM_LIBRARY_VISIBILITY FreeBSD : public Generic_ELF {
 public:
   FreeBSD(const Driver &D, const llvm::Triple& Triple, const ArgList &Args);
 
+  virtual CXXStdlibType GetCXXStdlibType(const ArgList &Args) const;
+
   virtual bool IsMathErrnoDefault() const { return false; }
   virtual bool IsObjCNonFragileABIDefault() const { return true; }
 
+  virtual void AddClangCXXStdlibIncludeArgs(const ArgList &DriverArgs,
+                                            ArgStringList &CC1Args) const;
+
   virtual bool UseSjLjExceptions() const;
 protected:
   virtual Tool *buildAssembler() const;
diff --git a/gnu/lib/Makefile b/gnu/lib/Makefile
index 6750403d66c5..50797fced309 100644
--- a/gnu/lib/Makefile
+++ b/gnu/lib/Makefile
@@ -10,7 +10,7 @@ SUBDIR+= libssp
 
 # libsupc++ uses libstdc++ headers, although 'make includes' should
 # have taken care of that already.
-.if ${MK_CXX} != "no"
+.if ${MK_GNUCXX} != "no"
 SUBDIR+= libstdc++ libsupc++
 .endif
 
diff --git a/gnu/usr.bin/cc/Makefile b/gnu/usr.bin/cc/Makefile
index efb548aaf62e..bf6d20c79ce4 100644
--- a/gnu/usr.bin/cc/Makefile
+++ b/gnu/usr.bin/cc/Makefile
@@ -12,7 +12,12 @@ SUBDIR+= cpp
 .endif
 
 .if ${MK_CXX} != "no"
-SUBDIR+= cc1plus c++ c++filt
+.if ${MK_GNUCXX} != "no"
+SUBDIR+= cc1plus c++ 
+.endif
+# This should be moved into the above block once c++filt from elftoolchain or
+# similar is provided.
+SUBDIR+= c++filt
 .endif
 
 .if ${MK_GCOV} != "no"
diff --git a/share/mk/bsd.own.mk b/share/mk/bsd.own.mk
index da758d54cbbb..3eb8e51a6731 100644
--- a/share/mk/bsd.own.mk
+++ b/share/mk/bsd.own.mk
@@ -284,7 +284,6 @@ __DEFAULT_YES_OPTIONS = \
     FP_LIBC \
     FREEBSD_UPDATE \
     GAMES \
-    GCC \
     GCOV \
     GDB \
     GNU \
@@ -400,6 +399,11 @@ __T=${TARGET_ARCH}
 .else
 __T=${MACHINE_ARCH}
 .endif
+.if defined(TARGET)
+__TT=${TARGET}
+.else
+__TT=${MACHINE_ARCH}
+.endif
 # Clang is only for x86, powerpc and little-endian arm right now, by default.
 .if ${__T} == "amd64" || ${__T} == "i386" || ${__T:Mpowerpc*}
 __DEFAULT_YES_OPTIONS+=CLANG CLANG_FULL
@@ -414,8 +418,30 @@ __DEFAULT_NO_OPTIONS+=CLANG CLANG_FULL
 .if ${__T} == "amd64" || ${__T} == "arm" || ${__T} == "armv6" || \
     ${__T} == "i386"
 __DEFAULT_YES_OPTIONS+=CLANG_IS_CC
+# The pc98 bootloader requires gcc to build and so we must leave gcc enabled
+# for pc98 for now.
+.if ${__TT} == "pc98"
+__DEFAULT_NO_OPTIONS+=GNUCXX
+__DEFAULT_YES_OPTIONS+=GCC
 .else
+__DEFAULT_NO_OPTIONS+=GCC GNUCXX
+.endif
+# The libc++ headers use c++11 extensions.  These are normally silenced because
+# they are treated as system headers, but we explicitly disable that warning
+# suppression when building the base system to catch bugs in our headers.
+# Eventually we'll want to start building the base system C++ code as C++11,
+# but not yet.
+CXXFLAGS+=	-Wno-c++11-extensions
+.else
+# If clang is not cc, then build gcc by default
 __DEFAULT_NO_OPTIONS+=CLANG_IS_CC
+__DEFAULT_YES_OPTIONS+=GCC
+# And if g++ is c++, build the rest of the GNU C++ stack
+.if defined(WITHOUT_CXX)
+__DEFAULT_NO_OPTIONS+=GNUCXX
+.else
+__DEFAULT_YES_OPTIONS+=GNUCXX
+.endif
 .endif
 # FDT is needed only for arm, mips and powerpc
 .if ${__T:Marm*} || ${__T:Mpowerpc*} || ${__T:Mmips*}
diff --git a/sys/sys/param.h b/sys/sys/param.h
index fa3e2eb78ffe..0099a4df376b 100644
--- a/sys/sys/param.h
+++ b/sys/sys/param.h
@@ -58,7 +58,7 @@
  *		in the range 5 to 9.
  */
 #undef __FreeBSD_version
-#define __FreeBSD_version 1000053	/* Master, propagated to newvers */
+#define __FreeBSD_version 1000054	/* Master, propagated to newvers */
 
 /*
  * __FreeBSD_kernel__ indicates that this system uses the kernel of FreeBSD,
diff --git a/tools/build/options/WITHOUT_GNUCXX b/tools/build/options/WITHOUT_GNUCXX
new file mode 100644
index 000000000000..ce10636009e2
--- /dev/null
+++ b/tools/build/options/WITHOUT_GNUCXX
@@ -0,0 +1,3 @@
+.\" $FreeBSD$
+Do not build the GNU C++ stack (g++, libstdc++).
+This is the default on platforms where clang is the system compiler.
diff --git a/tools/build/options/WITH_GNUCXX b/tools/build/options/WITH_GNUCXX
new file mode 100644
index 000000000000..c49e7cd9e1c4
--- /dev/null
+++ b/tools/build/options/WITH_GNUCXX
@@ -0,0 +1,3 @@
+.\" $FreeBSD$
+Build the GNU C++ stack (g++, libstdc++).
+This is the default on platforms where gcc is the system compiler.