PR47785: Add support for handling Xassembler/Wa options with LTO.

2020-02-24  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
	    Kugan Vivekandarajah  <kugan.vivekanandarajah@linaro.org>

	PR driver/47785
	* gcc.c (putenv_COLLECT_AS_OPTIONS): New function.
	(driver::main): Call putenv_COLLECT_AS_OPTIONS.
	* opts-common.c (parse_options_from_collect_gcc_options): New function.
	(prepend_xassembler_to_collect_as_options): Likewise.
	* opts.h (parse_options_from_collect_gcc_options): Declare prototype.
	(prepend_xassembler_to_collect_as_options): Likewise.
	* lto-opts.c (lto_write_options): Stream assembler options
	in COLLECT_AS_OPTIONS.
	* lto-wrapper.c (xassembler_options_error): New static variable.
	(get_options_from_collect_gcc_options): Move parsing options code to
	parse_options_from_collect_gcc_options and call it.
	(merge_and_complain): Validate -Xassembler options.
	(append_compiler_options): Handle OPT_Xassembler.
	(run_gcc): Append command line -Xassembler options to
	collect_gcc_options.
	* doc/invoke.texi: Add documentation about using Xassembler
	options with LTO.

testsuite/
	* gcc.target/arm/pr78353-1.c: New test.
	* gcc.target/arm/pr78353-2.c: Likewise.

10 files changed, 230 insertions, 32 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 49986c0e10d..b5fc309ce84 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,25 @@
+2020-02-24  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+	    Kugan Vivekandarajah  <kugan.vivekanandarajah@linaro.org>
+
+	PR driver/47785
+	* gcc.c (putenv_COLLECT_AS_OPTIONS): New function.
+	(driver::main): Call putenv_COLLECT_AS_OPTIONS.
+	* opts-common.c (parse_options_from_collect_gcc_options): New function.
+	(prepend_xassembler_to_collect_as_options): Likewise.
+	* opts.h (parse_options_from_collect_gcc_options): Declare prototype.
+	(prepend_xassembler_to_collect_as_options): Likewise.
+	* lto-opts.c (lto_write_options): Stream assembler options
+	in COLLECT_AS_OPTIONS.
+	* lto-wrapper.c (xassembler_options_error): New static variable.
+	(get_options_from_collect_gcc_options): Move parsing options code to
+	parse_options_from_collect_gcc_options and call it.
+	(merge_and_complain): Validate -Xassembler options.
+	(append_compiler_options): Handle OPT_Xassembler.
+	(run_gcc): Append command line -Xassembler options to
+	collect_gcc_options.
+	* doc/invoke.texi: Add documentation about using Xassembler
+	options with LTO.
+
 2020-02-24  Kito Cheng  <kito.cheng@sifive.com>
 
 	* config/riscv/riscv.c (riscv_emit_float_compare): Change the code gen
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 54017dfce8f..d4fe9a4d9d4 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -11159,6 +11159,12 @@ conflicting translation units.  Specifically
 precedence; and for example @option{-ffp-contract=off} takes precedence
 over @option{-ffp-contract=fast}.  You can override them at link time.
 
+When you need to pass options to the assembler via @option{-Wa} or
+@option{-Xassembler} make sure to either compile such translation
+units with @option{-fno-lto} or consistently use the same assembler
+options on all translation units.  You can alternatively also
+specify assembler options at LTO link time.
+
 To enable debug info generation you need to supply @option{-g} at
 compile time.  If any of the input files at link time were built
 with debug info generation enabled the link will enable debug info
diff --git a/gcc/gcc.c b/gcc/gcc.c
index effc384f3ef..9f790db0daf 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -5242,6 +5242,34 @@ do_specs_vec (vec<char_p> vec)
     }
 }
 
+/* Add options passed via -Xassembler or -Wa to COLLECT_AS_OPTIONS.  */
+
+static void
+putenv_COLLECT_AS_OPTIONS (vec<char_p> vec)
+{
+  if (vec.is_empty ())
+     return;
+
+  obstack_init (&collect_obstack);
+  obstack_grow (&collect_obstack, "COLLECT_AS_OPTIONS=",
+		strlen ("COLLECT_AS_OPTIONS="));
+
+  char *opt;
+  unsigned ix;
+
+  FOR_EACH_VEC_ELT (vec, ix, opt)
+    {
+      obstack_1grow (&collect_obstack, '\'');
+      obstack_grow (&collect_obstack, opt, strlen (opt));
+      obstack_1grow (&collect_obstack, '\'');
+      if (ix < vec.length () - 1)
+	obstack_1grow(&collect_obstack, ' ');
+    }
+
+  obstack_1grow (&collect_obstack, '\0');
+  xputenv (XOBFINISH (&collect_obstack, char *));
+}
+
 /* Process the sub-spec SPEC as a portion of a larger spec.
    This is like processing a whole spec except that we do
    not initialize at the beginning and we do not supply a
@@ -7363,6 +7391,7 @@ driver::main (int argc, char **argv)
   global_initializations ();
   build_multilib_strings ();
   set_up_specs ();
+  putenv_COLLECT_AS_OPTIONS (assembler_options);
   putenv_COLLECT_GCC (argv[0]);
   maybe_putenv_COLLECT_LTO_WRAPPER ();
   maybe_putenv_OFFLOAD_TARGETS ();
diff --git a/gcc/lto-opts.c b/gcc/lto-opts.c
index 90bfde5a8fd..87e916a2741 100644
--- a/gcc/lto-opts.c
+++ b/gcc/lto-opts.c
@@ -163,6 +163,12 @@ lto_write_options (void)
 	append_to_collect_gcc_options (&temporary_obstack, &first_p,
 				       option->canonical_option[j]);
     }
+
+  const char *collect_as_options = getenv ("COLLECT_AS_OPTIONS");
+  if (collect_as_options)
+    prepend_xassembler_to_collect_as_options (collect_as_options,
+					      &temporary_obstack);
+
   obstack_grow (&temporary_obstack, "\0", 1);
   args = XOBFINISH (&temporary_obstack, char *);
   lto_write_data (args, strlen (args) + 1);
diff --git a/gcc/lto-wrapper.c b/gcc/lto-wrapper.c
index fe8f292f877..6e3f294257e 100644
--- a/gcc/lto-wrapper.c
+++ b/gcc/lto-wrapper.c
@@ -73,6 +73,7 @@ static char *offload_objects_file_name;
 static char *makefile;
 static unsigned int num_deb_objs;
 static const char **early_debug_object_names;
+static bool xassembler_options_error = false;
 
 const char tool_name[] = "lto-wrapper";
 
@@ -137,42 +138,14 @@ get_options_from_collect_gcc_options (const char *collect_gcc,
 				      unsigned int *decoded_options_count)
 {
   struct obstack argv_obstack;
-  char *argv_storage;
   const char **argv;
-  int j, k, argc;
+  int argc;
 
-  argv_storage = xstrdup (collect_gcc_options);
   obstack_init (&argv_obstack);
   obstack_ptr_grow (&argv_obstack, collect_gcc);
 
-  for (j = 0, k = 0; argv_storage[j] != '\0'; ++j)
-    {
-      if (argv_storage[j] == '\'')
-	{
-	  obstack_ptr_grow (&argv_obstack, &argv_storage[k]);
-	  ++j;
-	  do
-	    {
-	      if (argv_storage[j] == '\0')
-		fatal_error (input_location,
-			     "malformed %<COLLECT_GCC_OPTIONS%>");
-	      else if (strncmp (&argv_storage[j], "'\\''", 4) == 0)
-		{
-		  argv_storage[k++] = '\'';
-		  j += 4;
-		}
-	      else if (argv_storage[j] == '\'')
-		break;
-	      else
-		argv_storage[k++] = argv_storage[j++];
-	    }
-	  while (1);
-	  argv_storage[k++] = '\0';
-	}
-    }
-
-  obstack_ptr_grow (&argv_obstack, NULL);
-  argc = obstack_object_size (&argv_obstack) / sizeof (void *) - 1;
+  parse_options_from_collect_gcc_options (collect_gcc_options,
+					  &argv_obstack, &argc);
   argv = XOBFINISH (&argv_obstack, const char **);
 
   decode_cmdline_options_to_array (argc, (const char **)argv, CL_DRIVER,
@@ -512,6 +485,45 @@ merge_and_complain (struct cl_decoded_option **decoded_options,
       }
    else
      j++;
+
+  if (!xassembler_options_error)
+    for (i = j = 0; ; i++, j++)
+      {
+	for (; i < *decoded_options_count; i++)
+	  if ((*decoded_options)[i].opt_index == OPT_Xassembler)
+	    break;
+
+	for (; j < fdecoded_options_count; j++)
+	  if (fdecoded_options[j].opt_index == OPT_Xassembler)
+	    break;
+
+	if (i == *decoded_options_count && j == fdecoded_options_count)
+	  break;
+	else if (i < *decoded_options_count && j == fdecoded_options_count)
+	  {
+	    warning (0, "Extra option to -Xassembler: %s,"
+		     " dropping all -Xassembler and -Wa options.",
+		     (*decoded_options)[i].arg);
+	    xassembler_options_error = true;
+	    break;
+	  }
+	else if (i == *decoded_options_count && j < fdecoded_options_count)
+	  {
+	    warning (0, "Extra option to -Xassembler: %s,"
+		     " dropping all -Xassembler and -Wa options.",
+		     fdecoded_options[j].arg);
+	    xassembler_options_error = true;
+	    break;
+	  }
+	else if (strcmp ((*decoded_options)[i].arg, fdecoded_options[j].arg))
+	  {
+	    warning (0, "Options to Xassembler do not match: %s, %s,"
+		     " dropping all -Xassembler and -Wa options.",
+		     (*decoded_options)[i].arg, fdecoded_options[j].arg);
+	    xassembler_options_error = true;
+	    break;
+	  }
+      }
 }
 
 /* Auxiliary function that frees elements of PTR and PTR itself.
@@ -626,6 +638,13 @@ append_compiler_options (obstack *argv_obstack, struct cl_decoded_option *opts,
 	case OPT_Os:
 	  break;
 
+	case OPT_Xassembler:
+	  /* When we detected a mismatch in assembler options between
+	     the input TU's fall back to previous behavior of ignoring them.  */
+	  if (xassembler_options_error)
+	    continue;
+	  break;
+
 	default:
 	  if (!(cl_options[option->opt_index].flags & CL_TARGET))
 	    continue;
@@ -1251,7 +1270,8 @@ run_gcc (unsigned argc, char *argv[])
   const char **argv_ptr;
   char *list_option_full = NULL;
   const char *linker_output = NULL;
-  const char *collect_gcc, *collect_gcc_options;
+  const char *collect_gcc;
+  char *collect_gcc_options;
   int parallel = 0;
   int jobserver = 0;
   int auto_parallel = 0;
@@ -1281,6 +1301,25 @@ run_gcc (unsigned argc, char *argv[])
   if (!collect_gcc_options)
     fatal_error (input_location,
 		 "environment variable %<COLLECT_GCC_OPTIONS%> must be set");
+
+  char *collect_as_options = getenv ("COLLECT_AS_OPTIONS");
+
+  /* Prepend -Xassembler to each option, and append the string
+     to collect_gcc_options.  */
+  if (collect_as_options)
+    {
+      obstack temporary_obstack;
+      obstack_init (&temporary_obstack);
+
+      prepend_xassembler_to_collect_as_options (collect_as_options,
+						&temporary_obstack);
+      obstack_1grow (&temporary_obstack, '\0');
+
+      char *xassembler_opts_string
+	= XOBFINISH (&temporary_obstack, char *);
+      strcat (collect_gcc_options, xassembler_opts_string);
+    }
+
   get_options_from_collect_gcc_options (collect_gcc, collect_gcc_options,
 					&decoded_options,
 					&decoded_options_count);
diff --git a/gcc/opts-common.c b/gcc/opts-common.c
index 112de159cce..de9510abd64 100644
--- a/gcc/opts-common.c
+++ b/gcc/opts-common.c
@@ -1739,3 +1739,69 @@ control_warning_option (unsigned int opt_index, int kind, const char *arg,
 	}
     }
 }
+
+/* Parse options in COLLECT_GCC_OPTIONS and push them on ARGV_OBSTACK.
+   Store number of arguments into ARGC_P.  */
+
+void
+parse_options_from_collect_gcc_options (const char *collect_gcc_options,
+					obstack *argv_obstack,
+					int *argc_p)
+{
+  char *argv_storage = xstrdup (collect_gcc_options);
+  int j, k;
+
+  for (j = 0, k = 0; argv_storage[j] != '\0'; ++j)
+    {
+      if (argv_storage[j] == '\'')
+	{
+	  obstack_ptr_grow (argv_obstack, &argv_storage[k]);
+	  ++j;
+	  do
+	    {
+	      if (argv_storage[j] == '\0')
+		fatal_error (input_location,
+			     "malformed %<COLLECT_GCC_OPTIONS%>");
+	      else if (strncmp (&argv_storage[j], "'\\''", 4) == 0)
+		{
+		  argv_storage[k++] = '\'';
+		  j += 4;
+		}
+	      else if (argv_storage[j] == '\'')
+		break;
+	      else
+		argv_storage[k++] = argv_storage[j++];
+	    }
+	  while (1);
+	  argv_storage[k++] = '\0';
+	}
+    }
+
+  obstack_ptr_grow (argv_obstack, NULL);
+  *argc_p = obstack_object_size (argv_obstack) / sizeof (void *) - 1;
+}
+
+/* Prepend -Xassembler for each option in COLLECT_AS_OPTIONS,
+   and push on O.  */
+
+void prepend_xassembler_to_collect_as_options (const char *collect_as_options,
+					       obstack *o)
+{
+  obstack opts_obstack;
+  int opts_count;
+
+  obstack_init (&opts_obstack);
+  parse_options_from_collect_gcc_options (collect_as_options,
+					  &opts_obstack, &opts_count);
+  const char **assembler_opts = XOBFINISH (&opts_obstack, const char **);
+
+  for (int i = 0; i < opts_count; i++)
+    {
+      obstack_grow (o, " '-Xassembler' ",
+		    strlen (" '-Xassembler' "));
+      const char *opt = assembler_opts[i];
+      obstack_1grow (o, '\'');
+      obstack_grow (o, opt, strlen (opt));
+      obstack_1grow (o, '\'');
+    }
+}
diff --git a/gcc/opts.h b/gcc/opts.h
index c6ad6c70464..8f594b46e33 100644
--- a/gcc/opts.h
+++ b/gcc/opts.h
@@ -460,6 +460,11 @@ extern bool parse_and_check_align_values (const char *flag,
 					  bool report_error,
 					  location_t loc);
 
+extern void parse_options_from_collect_gcc_options (const char *, obstack *,
+						    int *);
+
+extern void prepend_xassembler_to_collect_as_options (const char *, obstack *);
+
 /* Set OPTION in OPTS to VALUE if the option is not set in OPTS_SET.  */
 
 #define SET_OPTION_IF_UNSET(OPTS, OPTS_SET, OPTION, VALUE) \
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 06d61c7e2ee..13c1a132cc1 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2020-02-24  Prathamesh Kulkarni  <prathamesh.kulkarni@linaro.org>
+	    Kugan Vivekandarajah  <kugan.vivekanandarajah@linaro.org>
+
+	PR driver/47785
+	PR lto/78353
+	* gcc.target/arm/pr78353-1.c: New test.
+	* gcc.target/arm/pr78353-2.c: Likewise.
+
 2020-02-23  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/93890
diff --git a/gcc/testsuite/gcc.target/arm/pr78353-1.c b/gcc/testsuite/gcc.target/arm/pr78353-1.c
new file mode 100644
index 00000000000..aec0fb0cbfd
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr78353-1.c
@@ -0,0 +1,8 @@
+/* { dg-do link }  */
+/* { dg-options "-march=armv7-a -mthumb -O2 -flto -Wa,-mimplicit-it=always" }  */
+
+int main(int x)
+{
+  asm("teq %0, #0; addne %0, %0, #1" : "=r" (x));
+  return x;
+}
diff --git a/gcc/testsuite/gcc.target/arm/pr78353-2.c b/gcc/testsuite/gcc.target/arm/pr78353-2.c
new file mode 100644
index 00000000000..18a90e8834e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/pr78353-2.c
@@ -0,0 +1,9 @@
+/* { dg-do link }  */
+/* { dg-options "-march=armv7-a -mthumb -O2 -flto -Wa,-mimplicit-it=always,-mthumb" }  */
+
+int main(int x)
+{
+  asm("teq %0, #0; addne %0, %0, #1" : "=r" (x));
+  return x;
+}
+