* ldmain.h (ld_sysroot): Change type to a constant string.

* ldmain.c (ld_sysroot): Likewise.
	(get_relative_sysroot, get_sysroot): New functions, adding command-line
	support for changing the sysroot.
	(main): Call the new functions.
	* lexsup.c (OPTION_SYSROOT): New.
	(ld_options): Add --sysroot.
	(parse_args): Add a dummy handler for it.
	* ld.texinfo (--sysroot): Document.
	* NEWS: Mention the new --sysroot option.

ld/ChangeLog

@@ -1,3 +1,16 @@
+2005-01-19  Richard Sandiford  <rsandifo@redhat.com>
+
+	* ldmain.h (ld_sysroot): Change type to a constant string.
+	* ldmain.c (ld_sysroot): Likewise.
+	(get_relative_sysroot, get_sysroot): New functions, adding command-line
+	support for changing the sysroot.
+	(main): Call the new functions.
+	* lexsup.c (OPTION_SYSROOT): New.
+	(ld_options): Add --sysroot.
+	(parse_args): Add a dummy handler for it.
+	* ld.texinfo (--sysroot): Document.
+	* NEWS: Mention the new --sysroot option.
+
 2005-01-18  Alan Modra  <amodra@bigpond.net.au>
 
 	* ldlang.c (section_already_linked): Adjust bfd_link_just_syms call.

ld/NEWS

@@ -1,5 +1,9 @@
 -*- text -*-
 
+* A new command-line option, --sysroot, can be used to override the
+  default sysroot location.  It only applies to toolchains that were
+  configured using --with-sysroot.
+
 * New linker script functions: ORIGIN() and LENGTH() which return information
   about a specified memory region.
 

ld/ld.texinfo

@@ -1504,6 +1504,12 @@ many relocations.  @var{count} defaults to a value of 32768.
 Compute and display statistics about the operation of the linker, such
 as execution time and memory usage.
 
+@kindex --sysroot
+@item --sysroot=@var{directory}
+Use @var{directory} as the location of the sysroot, overriding the
+configure-time default.  This option is only supported by linkers
+that were configured using @option{--with-sysroot}.
+
 @kindex --traditional-format
 @cindex traditional format
 @item --traditional-format

ld/ldmain.c

@@ -68,7 +68,7 @@ const char *output_filename = "a.out";
 char *program_name;
 
 /* The prefix for system library directories.  */
-char *ld_sysroot;
+const char *ld_sysroot;
 
 /* The canonical representation of ld_sysroot.  */
 char * ld_canon_sysroot;
@@ -110,6 +110,8 @@ ld_config_type config;
 
 sort_type sort_section;
 
+static const char *get_sysroot
+  (int, char **);
 static char *get_emulation
   (int, char **);
 static void set_scripts_dir
@@ -201,47 +203,18 @@ main (int argc, char **argv)
 
   xatexit (remove_output);
 
-#ifdef TARGET_SYSTEM_ROOT_RELOCATABLE
-  ld_sysroot = make_relative_prefix (program_name, BINDIR,
-				     TARGET_SYSTEM_ROOT);
-
-  if (ld_sysroot)
+  /* Set up the sysroot directory.  */
+  ld_sysroot = get_sysroot (argc, argv);
+  if (*ld_sysroot)
     {
-      struct stat s;
-      int res = stat (ld_sysroot, &s) == 0 && S_ISDIR (s.st_mode);
-
-      if (!res)
+      if (*TARGET_SYSTEM_ROOT == 0)
 	{
-	  free (ld_sysroot);
-	  ld_sysroot = NULL;
+	  einfo ("%P%F: this linker was not configured to use sysroots");
+	  ld_sysroot = "";
 	}
+      else
+	ld_canon_sysroot = lrealpath (ld_sysroot);
     }
-
-  if (! ld_sysroot)
-    {
-      ld_sysroot = make_relative_prefix (program_name, TOOLBINDIR,
-					 TARGET_SYSTEM_ROOT);
-
-      if (ld_sysroot)
-	{
-	  struct stat s;
-	  int res = stat (ld_sysroot, &s) == 0 && S_ISDIR (s.st_mode);
-
-	  if (!res)
-	    {
-	      free (ld_sysroot);
-	      ld_sysroot = NULL;
-	    }
-	}
-    }
-
-  if (! ld_sysroot)
-#endif
-    ld_sysroot = TARGET_SYSTEM_ROOT;
-
-  if (ld_sysroot && *ld_sysroot)
-    ld_canon_sysroot = lrealpath (ld_sysroot);
-
   if (ld_canon_sysroot)
     ld_canon_sysroot_len = strlen (ld_canon_sysroot);
   else
@@ -587,6 +560,51 @@ main (int argc, char **argv)
   return 0;
 }
 
+/* If the configured sysroot is relocatable, try relocating it based on
+   default prefix FROM.  Return the relocated directory if it exists,
+   otherwise return null.  */
+
+static char *
+get_relative_sysroot (const char *from ATTRIBUTE_UNUSED)
+{
+#ifdef TARGET_SYSTEM_ROOT_RELOCATABLE
+  char *path;
+  struct stat s;
+
+  path = make_relative_prefix (program_name, from, TARGET_SYSTEM_ROOT);
+  if (path)
+    {
+      if (stat (path, &s) == 0 && S_ISDIR (s.st_mode))
+	return path;
+      free (path);
+    }
+#endif
+  return 0;
+}
+
+/* Return the sysroot directory.  Return "" if no sysroot is being used.  */
+
+static const char *
+get_sysroot (int argc, char **argv)
+{
+  int i;
+  const char *path;
+
+  for (i = 1; i < argc; i++)
+    if (strncmp (argv[i], "--sysroot=", strlen ("--sysroot=")) == 0)
+      return argv[i] + strlen ("--sysroot=");
+
+  path = get_relative_sysroot (BINDIR);
+  if (path)
+    return path;
+
+  path = get_relative_sysroot (TOOLBINDIR);
+  if (path)
+    return path;
+
+  return TARGET_SYSTEM_ROOT;
+}
+
 /* We need to find any explicitly given emulation in order to initialize the
    state that's needed by the lex&yacc argument parser (parse_args).  */
 

ld/ldmain.h

@@ -23,7 +23,7 @@
 #define LDMAIN_H
 
 extern char *program_name;
-extern char *ld_sysroot;
+extern const char *ld_sysroot;
 extern char *ld_canon_sysroot;
 extern int ld_canon_sysroot_len;
 extern bfd *output_bfd;

ld/lexsup.c

@@ -71,6 +71,7 @@ enum option_values
   OPTION_DEFSYM,
   OPTION_DEMANGLE,
   OPTION_DYNAMIC_LINKER,
+  OPTION_SYSROOT,
   OPTION_EB,
   OPTION_EL,
   OPTION_EMBEDDED_RELOCS,
@@ -233,6 +234,8 @@ static const struct ld_option ld_options[] =
   { {"library-path", required_argument, NULL, 'L'},
     'L', N_("DIRECTORY"), N_("Add DIRECTORY to library search path"),
     TWO_DASHES },
+  { {"sysroot=<DIRECTORY>", required_argument, NULL, OPTION_SYSROOT},
+    '\0', NULL, N_("Override the default sysroot location"), TWO_DASHES },
   { {NULL, required_argument, NULL, '\0'},
     'm', N_("EMULATION"), N_("Set emulation"), ONE_DASH },
   { {"print-map", no_argument, NULL, 'M'},
@@ -747,6 +750,9 @@ parse_args (unsigned argc, char **argv)
 	case OPTION_DYNAMIC_LINKER:
 	  command_line.interpreter = optarg;
 	  break;
+	case OPTION_SYSROOT:
+	  /* Already handled in ldmain.c.  */
+	  break;
 	case OPTION_EB:
 	  command_line.endian = ENDIAN_BIG;
 	  break;