llvm: pass library paths for cross-build

[Patrick Wildt]

Hi,

with GCC as cross-compiler the PREFIX define (which is set to the
CROSSDIR) makes sure that the linker includes the correct dirs.
Otherwise the cross-build will only find the host libraries, which
does not really work well.

Our clang doesn't do this so far.  The changes in clang make sure that

  * the library paths are passed to ld(1) and
  * the library path /usr/lib is prefixed with the sysroot.

Then we need to make sure to invoke our cross-clang with --sysroot
${CROSSDIR}.  For this, simply replace the cc and c++ binary with
a wrapper that calls clang with the correct mode and options.

Comments?

Patrick

diff --git a/Makefile.cross b/Makefile.cross
index 01c1c843953..9c5dbe8b5a5 100644
--- a/Makefile.cross
+++ b/Makefile.cross
@@ -238,10 +238,13 @@ ${CROSSGCC}:              ${CROSSBINUTILS}
            ${MAKE} install)
        mv ${CROSSDIR}/usr/bin/clang ${CROSSDIR}/usr/bin/${TARGET_CANON}-clang
        mv ${CROSSDIR}/usr/bin/clang++ 
${CROSSDIR}/usr/bin/${TARGET_CANON}-clang++
-       cp -f ${CROSSDIR}/usr/bin/${TARGET_CANON}-clang 
${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-cc
-       cp -f ${CROSSDIR}/usr/bin/${TARGET_CANON}-clang++ 
${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-c++
+       cp -f ${CROSSDIR}/usr/bin/${TARGET_CANON}-clang 
${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-clang
        ln -sf ${TARGET_CANON}-cc ${CROSSDIR}/usr/${TARGET_CANON}/bin/cc
        ln -sf ${TARGET_CANON}-c++ ${CROSSDIR}/usr/${TARGET_CANON}/bin/c++
+       echo  
"#!/bin/sh\n${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-clang --sysroot 
${CROSSDIR} \"$$""@\"" > 
${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-cc; \
+       chmod +x ${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-cc;
+       echo  
"#!/bin/sh\n${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-clang 
--driver-mode=g++ --sysroot ${CROSSDIR} \"$$""@\"" > 
${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-c++; \
+       chmod +x ${CROSSDIR}/usr/${TARGET_CANON}/bin/${TARGET_CANON}-c++;
 .elif ${COMPILER_VERSION:L} == "gcc3"
        (cd ${.CURDIR}/gnu/usr.bin/gcc; \
            MAKEOBJDIR=obj.${MACHINE}.${TARGET} \
diff --git a/gnu/llvm/tools/clang/lib/Driver/ToolChains.cpp 
b/gnu/llvm/tools/clang/lib/Driver/ToolChains.cpp
index 45622b22ab5..7ba8f25efdd 100644
--- a/gnu/llvm/tools/clang/lib/Driver/ToolChains.cpp
+++ b/gnu/llvm/tools/clang/lib/Driver/ToolChains.cpp
@@ -2977,7 +2977,7 @@ OpenBSD::OpenBSD(const Driver &D, const llvm::Triple 
&Triple,
                  const ArgList &Args)
     : Generic_ELF(D, Triple, Args) {
   getFilePaths().push_back(getDriver().Dir + "/../lib");
-  getFilePaths().push_back("/usr/lib");
+  getFilePaths().push_back(getDriver().SysRoot + "/usr/lib");
 }
 
 Tool *OpenBSD::buildAssembler() const {
diff --git a/gnu/llvm/tools/clang/lib/Driver/Tools.cpp 
b/gnu/llvm/tools/clang/lib/Driver/Tools.cpp
index 656a8fbbdaf..34cbd620b4b 100644
--- a/gnu/llvm/tools/clang/lib/Driver/Tools.cpp
+++ b/gnu/llvm/tools/clang/lib/Driver/Tools.cpp
@@ -7623,8 +7623,10 @@ void openbsd::Linker::ConstructJob(Compilation &C, const 
JobAction &JA,
     }
   }
 
-  Args.AddAllArgs(CmdArgs, {options::OPT_L, options::OPT_T_Group,
-                            options::OPT_e, options::OPT_s, options::OPT_t,
+  Args.AddAllArgs(CmdArgs, options::OPT_L);
+  getToolChain().AddFilePathLibArgs(Args, CmdArgs);
+  Args.AddAllArgs(CmdArgs, {options::OPT_T_Group, options::OPT_e,
+                            options::OPT_s, options::OPT_t,
                             options::OPT_Z_Flag, options::OPT_r});
 
   AddLinkerInputs(getToolChain(), Inputs, Args, CmdArgs);