spec: add a spec function to join arguments

When passing `-o` flags to other options, the typical `-o foo` spelling
leaves a leading whitespace when replacing elsewhere. This ends up
creating flags spelled as `-some-option-with-arg= foo.ext` which doesn't
parse properly. When attempting to make a spec function to just remove
the leading whitespace, the argument splitting ends up masking the
whitespace. However, the intended extension *also* ends up being its own
argument. To perform the desired behavior, the arguments need to be
concatenated together.

gcc/:

	* gcc.cc (join_spec_func): Add a spec function to join all
	arguments.

Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
Co-authored-by: Jason Merrill <jason@redhat.com>

diff --git a/gcc/gcc.cc b/gcc/gcc.cc
index a9dd0eb655c5394b692d5376368c2739d1b42ef6..586fdb54ee74900b546c7807755454578a6bd189 100644 (file)
--- a/gcc/gcc.cc
+++ b/gcc/gcc.cc
@@ -447,6 +447,7 @@ static const char *greater_than_spec_func (int, const char **);
 static const char *debug_level_greater_than_spec_func (int, const char **);
 static const char *dwarf_version_greater_than_spec_func (int, const char **);
 static const char *find_fortran_preinclude_file (int, const char **);
+static const char *join_spec_func (int, const char **);
 static char *convert_white_space (char *);
 static char *quote_spec (char *);
 static char *quote_spec_arg (char *);
@@ -1772,6 +1773,7 @@ static const struct spec_function static_spec_functions[] =
   { "debug-level-gt",          debug_level_greater_than_spec_func },
   { "dwarf-version-gt",                dwarf_version_greater_than_spec_func },
   { "fortran-preinclude-file", find_fortran_preinclude_file},
+  { "join",                    join_spec_func},
 #ifdef EXTRA_SPEC_FUNCTIONS
   EXTRA_SPEC_FUNCTIONS
 #endif
@@ -10975,6 +10977,27 @@ find_fortran_preinclude_file (int argc, const char **argv)
   return result;
 }
 
+/* The function takes any number of arguments and joins them together.
+
+   This seems to be necessary to build "-fjoined=foo.b" from "-fseparate foo.a"
+   with a %{fseparate*:-fjoined=%.b$*} rule without adding undesired spaces:
+   when doing $* replacement we first replace $* with the rest of the switch
+   (in this case ""), and then add any arguments as arguments after the result,
+   resulting in "-fjoined= foo.b".  Using this function with e.g.
+   %{fseparate*:-fjoined=%:join(%.b$*)} gets multiple words as separate argv
+   elements instead of separated by spaces, and we paste them together.  */
+
+static const char *
+join_spec_func (int argc, const char **argv)
+{
+  if (argc == 1)
+    return argv[0];
+  for (int i = 0; i < argc; ++i)
+    obstack_grow (&obstack, argv[i], strlen (argv[i]));
+  obstack_1grow (&obstack, '\0');
+  return XOBFINISH (&obstack, const char *);
+}
+
 /* If any character in ORIG fits QUOTE_P (_, P), reallocate the string
    so as to precede every one of them with a backslash.  Return the
    original string or the reallocated one.  */