[hexagon] restore library path arguments

[bcain]

Summary

Before applying this fix, clang would not include the specified library
path arguments:

$ ./bin/clang --target=hexagon-unknown-linux-musl  -o tprog tprog.o -L/tmp -###
...
clang: warning: argument unused during compilation: '-L/tmp' [-Wunused-command-line-argument]
 "/local/mnt/workspace/install/clang-latest/bin/ld.lld" "-z" "relro" "-o" "tprog" "-dynamic-linker=/lib/ld-musl-hexagon.so.1" "/usr/lib/crt1.o" "-L/usr/lib" "tprog.o" "-lclang_rt.builtins-hexagon" "-lc"

[MaskRay]

Tip: use %clang -fdriver-only -Werror -v to test that a command produces no warning or error and has an exit code of 0. Without it your Args.ClaimAllArgs(options::OPT_L); change is untested.

clang/test/Driver/hexagon-toolchain-linux.c

123

-target has been deprecated since Clang 3.4. Prefer --target= for new tests.
I think you can place %s on this %clang ... line.

125

too early wrapping?

129

Prefer quoting driver's cc1 output, "-L/tmp"

[bcain]

In D156330#4535974, @MaskRay wrote:

Tip: use %clang -fdriver-only -Werror -v to test that a command produces no warning or error and has an exit code of 0. Without it your Args.ClaimAllArgs(options::OPT_L); change is untested.

This test fails on the baseline because of the CHECK-NOT: warning: IIRC. But your suggestion sounds like a good one anyways, will do!

[bcain]

Fixed target: --target=hexagon-unknown-linux was not correct for testing this bug, it should have been --target=hexagon-unknown-linux-musl.

Used -fdriver-only -Werror as suggested but it did require separating the tests.

Quoted the library path arg, to make match from -cc1 command stricter, from review suggestion.

Fixed wrapping.

[MaskRay]

In D156330#4536827, @bcain wrote:

Fixed target: --target=hexagon-unknown-linux was not correct for testing this bug, it should have been --target=hexagon-unknown-linux-musl.

Used -fdriver-only -Werror as suggested but it did require separating the tests.

Quoted the library path arg, to make match from -cc1 command stricter, from review suggestion.

Fixed wrapping.

-fdriver-only -v -Werror is preferred because -### has a quirk. I hope we will fix it in the near future: D156363 :) Your change doesn't need to be blocked by that.

[bcain]

I misunderstood the previous suggestion about -fdriver-only -Werror -v and thought I needed to separate the test into two invocations. Combined these back into a single RUN now.

[bcain]

Too hasty w/the last update - forgot to remove the -###.

clang/lib/Driver/ToolChains/Hexagon.cpp

if (!Args.hasArg(options::OPT_nostdlib, options::OPT_nodefaultlibs)) {
 
       CmdArgs.push_back("-lclang_rt.builtins-hexagon");
       CmdArgs.push_back("-lc");
     }
     if (D.CCCIsCXX()) {
       if (HTC.ShouldLinkCXXStdlib(Args))
         HTC.AddCXXStdlibLibArgs(Args, CmdArgs);
     }
-    return;
   }
 
   //----------------------------------------------------------------------------
   // moslib
   //----------------------------------------------------------------------------
   std::vector<std::string> OsLibs;
   bool HasStandalone = false;
   for (const Arg *A : Args.filtered(options::OPT_moslib_EQ)) {
constructHexagonLinkArgs(Compilation &C, const JobAction &JA,
   }
 
   //----------------------------------------------------------------------------
   // Library Search Paths
   //----------------------------------------------------------------------------
   const ToolChain::path_list &LibPaths = HTC.getFilePaths();
   for (const auto &LibPath : LibPaths)
     CmdArgs.push_back(Args.MakeArgString(StringRef("-L") + LibPath));
+  Args.ClaimAllArgs(options::OPT_L);
 
   //----------------------------------------------------------------------------
   //
   //----------------------------------------------------------------------------
   Args.AddAllArgs(CmdArgs, {options::OPT_T_Group, options::OPT_s,
                             options::OPT_t, options::OPT_u_Group});
 
   AddLinkerInputs(HTC, Inputs, Args, CmdArgs, JA);

clang/test/Driver/hexagon-toolchain-linux.c

 // RUN:   -ccc-install-dir %S/Inputs/hexagon_tree/Tools/bin \
 // RUN:   -resource-dir=%S/Inputs/resource_dir \
 // RUN:   %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=CHECK009 %s
 // CHECK009:   InstalledDir: [[INSTALLED_DIR:.+]]
 // CHECK009:   "-resource-dir" "[[RESOURCE:[^"]+]]"
 // CHECK009-SAME: {{^}} "-internal-isystem" "[[RESOURCE]]/include"
 // CHECK009-SAME: {{^}} "-internal-externc-isystem" "[[INSTALLED_DIR]]/../target/hexagon/include"
+
+// RUN: %clang -fdriver-only -Werror -v -L/tmp \
+// RUN:    --target=hexagon-unknown-linux-musl %s -### 2>&1 \
+// RUN:    | FileCheck -check-prefix=CHECK010 %s
+// CHECK010:   InstalledDir: [[INSTALLED_DIR:.+]]
+// CHECK010:   "-L/tmp"