[Driver] Support default libc++ library location on Darwin

Darwin driver currently uses libc++ headers that are part of Clang
toolchain when available (by default ../include/c++/v1 relative to
executable), but it completely ignores the libc++ library itself
because it doesn't pass the location of libc++ library that's part
of Clang (by default ../lib relative to the exceutable) to the linker
always using the system copy of libc++.

This may lead to subtle issues when the compilation fails because the
headers that are part of Clang toolchain are incompatible with the
system library. Either the driver should ignore both headers as well as
the library, or it should always try to use both when available.

This patch changes the driver behavior to do the latter which seems more
reasonable, it makes it easy to test and use custom libc++ build on
Darwin while still allowing the use of system version. This also matches
the Clang driver behavior on other systems.

Differential Revision: https://reviews.llvm.org/D45639

diff --git a/clang/lib/Driver/ToolChains/Darwin.cpp b/clang/lib/Driver/ToolChains/Darwin.cpp
index bc59b6b..06d4f2f 100644 (file)
--- a/clang/lib/Driver/ToolChains/Darwin.cpp
+++ b/clang/lib/Driver/ToolChains/Darwin.cpp
@@ -615,6 +615,8 @@ void darwin::Linker::ConstructJob(Compilation &C, const JobAction &JA,
 
   Args.AddAllArgs(CmdArgs, options::OPT_L);
 
+  getToolChain().AddFilePathLibArgs(Args, CmdArgs);
+
   AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs, JA);
   // Build the input file for -filelist (list of linker input files) in case we
   // need it later
@@ -802,6 +804,7 @@ MachO::MachO(const Driver &D, const llvm::Triple &Triple, const ArgList &Args)
   getProgramPaths().push_back(getDriver().getInstalledDir());
   if (getDriver().getInstalledDir() != getDriver().Dir)
     getProgramPaths().push_back(getDriver().Dir);
+  getFilePaths().push_back(getDriver().Dir + "/../lib");
 }
 
 /// Darwin - Darwin tool chain for i386 and x86_64.

diff --git a/clang/test/Driver/darwin-ld.c b/clang/test/Driver/darwin-ld.c
index 15e5d10..4de850f 100644 (file)
--- a/clang/test/Driver/darwin-ld.c
+++ b/clang/test/Driver/darwin-ld.c
@@ -365,3 +365,8 @@
 // RUN: FileCheck -check-prefix=MNO_OUTLINE %s < %t.log
 // MNO_OUTLINE: {{ld(.exe)?"}}
 // MNO_OUTLINE-SAME: "-mllvm" "-enable-machine-outliner=never"
+
+// RUN: %clang -target x86_64-apple-darwin10 -### %t.o 2> %t.log
+// RUN: FileCheck -check-prefix=INSTALL-DIR %s < %t.log
+// INSTALL-DIR: InstalledDir: [[INSTALLDIR:.+$]]
+// INSTALL-DIR: "-L[[INSTALLDIR]]/../lib"