[clang] hexagon: fix link order for libc/builtins (#117057)

When linking programs with `eld`, we get a link error like below:

Error:
/inst/clang+llvm-19.1.0-cross-hexagon-unknown-linux-musl/x86_64-linux-gnu/bin/../target/hexagon-unknown-linux-musl//usr/lib/libc.a(scalbn.lo)(.text.scalbn+0x3c):
undefined reference to `__hexagon_muldf3'

libc has references to the clang_rt builtins library, so the order of
the libraries should be reversed.

(cherry picked from commit 9cc2502)

Author: androm3da

clang/lib/Driver/ToolChains/Hexagon.cpp

@@ -379,9 +379,9 @@ constructHexagonLinkArgs(Compilation &C, const JobAction &JA,
       if (NeedsXRayDeps)
         linkXRayRuntimeDeps(HTC, Args, CmdArgs);
 
-      CmdArgs.push_back("-lclang_rt.builtins-hexagon");
       if (!Args.hasArg(options::OPT_nolibc))
         CmdArgs.push_back("-lc");
+      CmdArgs.push_back("-lclang_rt.builtins-hexagon");
     }
     if (D.CCCIsCXX()) {
       if (HTC.ShouldLinkCXXStdlib(Args))

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

@@ -11,7 +11,7 @@
 // CHECK000-NOT:  {{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crti.o
 // CHECK000:      "-dynamic-linker={{/|\\\\}}lib{{/|\\\\}}ld-musl-hexagon.so.1"
 // CHECK000:      "{{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crt1.o"
-// CHECK000:      "-lclang_rt.builtins-hexagon" "-lc"
+// CHECK000:      "-lc" "-lclang_rt.builtins-hexagon"
 // -----------------------------------------------------------------------------
 // Passing --musl --shared
 // -----------------------------------------------------------------------------
@@ -21,7 +21,7 @@
 // RUN:   --sysroot=%S/Inputs/basic_linux_libcxx_tree -shared %s 2>&1 | FileCheck -check-prefix=CHECK001 %s
 // CHECK001-NOT:    -dynamic-linker={{/|\\\\}}lib{{/|\\\\}}ld-musl-hexagon.so.1
 // CHECK001:        "{{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crti.o"
-// CHECK001:        "-lclang_rt.builtins-hexagon" "-lc"
+// CHECK001:        "-lc" "-lclang_rt.builtins-hexagon"
 // CHECK001-NOT:    {{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crt1.o
 // -----------------------------------------------------------------------------
 // Passing --musl -nostdlib
@@ -33,8 +33,8 @@
 // CHECK002:       "-dynamic-linker={{/|\\\\}}lib{{/|\\\\}}ld-musl-hexagon.so.1"
 // CHECK002-NOT:   {{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crti.o
 // CHECK002-NOT:   {{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crt1.o
-// CHECK002-NOT:   "-lclang_rt.builtins-hexagon"
 // CHECK002-NOT:   "-lc"
+// CHECK002-NOT:   "-lclang_rt.builtins-hexagon"
 // -----------------------------------------------------------------------------
 // Passing --musl -nostartfiles
 // -----------------------------------------------------------------------------
@@ -45,7 +45,7 @@
 // CHECK003:       "-dynamic-linker={{/|\\\\}}lib{{/|\\\\}}ld-musl-hexagon.so.1"
 // CHECK003-NOT:   {{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}Scrt1.o
 // CHECK003-NOT:   {{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crt1.o
-// CHECK003:       "-lclang_rt.builtins-hexagon" "-lc"
+// CHECK003:       "-lc" "-lclang_rt.builtins-hexagon"
 // -----------------------------------------------------------------------------
 // Passing --musl -nodefaultlibs
 // -----------------------------------------------------------------------------
@@ -55,8 +55,8 @@
 // RUN:   --sysroot=%S/Inputs/basic_linux_libcxx_tree -nodefaultlibs %s 2>&1 | FileCheck -check-prefix=CHECK004 %s
 // CHECK004:       "-dynamic-linker={{/|\\\\}}lib{{/|\\\\}}ld-musl-hexagon.so.1"
 // CHECK004:       "{{.*}}basic_linux_libcxx_tree{{/|\\\\}}usr{{/|\\\\}}lib{{/|\\\\}}crt1.o"
-// CHECK004-NOT:   "-lclang_rt.builtins-hexagon"
 // CHECK004-NOT:   "-lc"
+// CHECK004-NOT:   "-lclang_rt.builtins-hexagon"
 // -----------------------------------------------------------------------------
 // Passing --musl -nolibc
 // -----------------------------------------------------------------------------