compiler wrapper: fix -Xlinker parsing (#35929)

* compiler wrapper: fix -Xlinker parsing
* handle the case of -rpath without value; avoid that we drop the flag
* also handle the -Xlinker -rpath -Xlinker without further args case...
* fix test
* get rid of global $rp var, reduce branching

lib/spack/env/cc

@@ -430,21 +430,37 @@ other_args_list=""
 # Global state for keeping track of -Wl,-rpath -Wl,/path
 wl_expect_rpath=no
 
+# Same, but for -Xlinker -rpath -Xlinker /path
+xlinker_expect_rpath=no
+
 parse_Wl() {
     # drop -Wl
     shift
     while [ $# -ne 0 ]; do
     if [ "$wl_expect_rpath" = yes ]; then
-        rp="$1"
+        if system_dir "$1"; then
+            append system_rpath_dirs_list "$1"
+        else
+            append rpath_dirs_list "$1"
+        fi
         wl_expect_rpath=no
     else
-        rp=""
         case "$1" in
             -rpath=*)
-                rp="${1#-rpath=}"
+                arg="${1#-rpath=}"
+                if system_dir "$arg"; then
+                    append system_rpath_dirs_list "$arg"
+                else
+                    append rpath_dirs_list "$arg"
+                fi
                 ;;
             --rpath=*)
-                rp="${1#--rpath=}"
+                arg="${1#--rpath=}"
+                if system_dir "$arg"; then
+                    append system_rpath_dirs_list "$arg"
+                else
+                    append rpath_dirs_list "$arg"
+                fi
                 ;;
             -rpath|--rpath)
                 wl_expect_rpath=yes
@@ -456,17 +472,8 @@ parse_Wl() {
                 ;;
         esac
     fi
-    if [ -n "$rp" ]; then
-        if system_dir "$rp"; then
-            append system_rpath_dirs_list "$rp"
-        else
-            append rpath_dirs_list "$rp"
-        fi
-    fi
     shift
     done
-    # By lack of local variables, always set this to empty string.
-    rp=""
 }
 
 
@@ -573,38 +580,72 @@ while [ $# -ne 0 ]; do
             unset IFS
             ;;
         -Xlinker)
-            if [ "$2" = "-rpath" ]; then
+            shift
-                if [ "$3" != "-Xlinker" ]; then
+            if [ $# -eq 0 ]; then
-                    die "-Xlinker,-rpath was not followed by -Xlinker,*"
+                # -Xlinker without value: let the compiler error about it.
+                append other_args_list -Xlinker
+                xlinker_expect_rpath=no
+                break
+            elif [ "$xlinker_expect_rpath" = yes ]; then
+                # Register the path of -Xlinker -rpath <other args> -Xlinker <path>
+                if system_dir "$1"; then
+                    append system_rpath_dirs_list "$1"
+                else
+                    append rpath_dirs_list "$1"
                 fi
-                shift 3;
+                xlinker_expect_rpath=no
-                rp="$1"
-            elif [ "$2" = "$dtags_to_strip" ]; then
-                shift  # We want to remove explicitly this flag
             else
-                append other_args_list "$1"
+                case "$1" in
+                    -rpath=*)
+                        arg="${1#-rpath=}"
+                        if system_dir "$arg"; then
+                            append system_rpath_dirs_list "$arg"
+                        else
+                            append rpath_dirs_list "$arg"
+                        fi
+                        ;;
+                    --rpath=*)
+                        arg="${1#--rpath=}"
+                        if system_dir "$arg"; then
+                            append system_rpath_dirs_list "$arg"
+                        else
+                            append rpath_dirs_list "$arg"
+                        fi
+                        ;;
+                    -rpath|--rpath)
+                        xlinker_expect_rpath=yes
+                        ;;
+                    "$dtags_to_strip")
+                        ;;
+                    *)
+                        append other_args_list -Xlinker
+                        append other_args_list "$1"
+                        ;;
+                esac
             fi
             ;;
+        "$dtags_to_strip")
+            ;;
         *)
-            if [ "$1" = "$dtags_to_strip" ]; then
+            append other_args_list "$1"
-                :  # We want to remove explicitly this flag
-            else
-                append other_args_list "$1"
-            fi
             ;;
     esac
-
-    # test rpaths against system directories in one place.
-    if [ -n "$rp" ]; then
-        if system_dir "$rp"; then
-            append system_rpath_dirs_list "$rp"
-        else
-            append rpath_dirs_list "$rp"
-        fi
-    fi
     shift
 done
 
+# We found `-Xlinker -rpath` but no matching value `-Xlinker /path`. Just append
+# `-Xlinker -rpath` again and let the compiler or linker handle the error during arg
+# parsing.
+if [ "$xlinker_expect_rpath" = yes ]; then
+    append other_args_list -Xlinker
+    append other_args_list -rpath
+fi
+
+# Same, but for -Wl flags.
+if [ "$wl_expect_rpath" = yes ]; then
+    append other_args_list -Wl,-rpath
+fi
+
 #
 # Add flags from Spack's cppflags, cflags, cxxflags, fcflags, fflags, and
 # ldflags. We stick to the order that gmake puts the flags in by default.

lib/spack/spack/test/cc.py

@@ -352,6 +352,53 @@ def test_Wl_parsing(wrapper_environment):
     )
 
 
+def test_Xlinker_parsing(wrapper_environment):
+    # -Xlinker <x> ... -Xlinker <y> may have compiler flags inbetween, like -O3 in this
+    # example. Also check that a trailing -Xlinker (which is a compiler error) is not
+    # dropped or given an empty argument.
+    check_args(
+        cc,
+        [
+            "-Xlinker",
+            "-rpath",
+            "-O3",
+            "-Xlinker",
+            "/a",
+            "-Xlinker",
+            "--flag",
+            "-Xlinker",
+            "-rpath=/b",
+            "-Xlinker",
+        ],
+        [real_cc]
+        + target_args
+        + [
+            "-Wl,--disable-new-dtags",
+            "-Wl,-rpath,/a",
+            "-Wl,-rpath,/b",
+            "-O3",
+            "-Xlinker",
+            "--flag",
+            "-Xlinker",
+        ],
+    )
+
+
+def test_rpath_without_value(wrapper_environment):
+    # cc -Wl,-rpath without a value shouldn't drop -Wl,-rpath;
+    # same for -Xlinker
+    check_args(
+        cc,
+        ["-Wl,-rpath", "-O3", "-g"],
+        [real_cc] + target_args + ["-Wl,--disable-new-dtags", "-O3", "-g", "-Wl,-rpath"],
+    )
+    check_args(
+        cc,
+        ["-Xlinker", "-rpath", "-O3", "-g"],
+        [real_cc] + target_args + ["-Wl,--disable-new-dtags", "-O3", "-g", "-Xlinker", "-rpath"],
+    )
+
+
 def test_dep_rpath(wrapper_environment):
     """Ensure RPATHs for root package are added."""
     check_args(cc, test_args, [real_cc] + target_args + common_compile_args)