[PATCH 2/2] Fortran: add attribute target_clones

[Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>]

Hi!

Add support for attribute target_clones:
!GCC$ ATTRIBUTES target_clones("arch1", "arch3","default") :: mysubroutine

Bootstrapped and regtested on x86_64-unknown-linux with
--target_board=unix'{-m32,-m64}'.
OK for trunk?

gcc/fortran/ChangeLog:

	* decl.cc: Include fold-const.h for size_int.
	(gfc_match_gcc_attribute_args): New internal helper function.
	(gfc_match_gcc_attributes): Handle target_clones.
	* f95-lang.cc (struct attribute_spec): Add target and
	target_clones entries.
	* gfortran.h (ext_attr_id_t): Add EXT_ATTR_TARGET_CLONES.
	(struct symbol_attribute): Add field ext_attr_args.
	* trans-decl.cc (add_attributes_to_decl): Also add ext_attr_args
	to the decl's attributes.
	* gfortran.texi: Document attribute target_clones.

gcc/testsuite/ChangeLog:

	* gfortran.dg/attr_target_clones-1.F90: New test.

Cc: gfortran ML <fortran@gcc.gnu.org>
---
 gcc/fortran/decl.cc                           | 104 ++++++++++++++++++
 gcc/fortran/f95-lang.cc                       |   4 +
 gcc/fortran/gfortran.h                        |   2 +
 gcc/fortran/gfortran.texi                     |  31 ++++++
 gcc/fortran/trans-decl.cc                     |   3 +
 .../gfortran.dg/attr_target_clones-1.F90      |  30 +++++
 6 files changed, 174 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/attr_target_clones-1.F90

diff --git a/gcc/fortran/decl.cc b/gcc/fortran/decl.cc
index 0f9b2ced4c2..3a619dbdd34 100644
--- a/gcc/fortran/decl.cc
+++ b/gcc/fortran/decl.cc
@@ -23,6 +23,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "coretypes.h"
 #include "options.h"
 #include "tree.h"
+#include "fold-const.h"
 #include "gfortran.h"
 #include "stringpool.h"
 #include "match.h"
@@ -11709,6 +11710,96 @@ gfc_match_final_decl (void)
   return MATCH_YES;
 }
 
+/* Internal helper to parse attribute argument list.
+   If REQUIRE_STRING is true, then require a string.
+   If ALLOW_MULTIPLE is true, allow more than one arg.
+   If multiple arguments are passed, require braces around them.
+   Returns a tree_list of arguments or NULL_TREE.  */
+static tree
+gfc_match_gcc_attribute_args (bool require_string, bool allow_multiple)
+{
+  tree attr_args = NULL_TREE, attr_arg;
+  char name[GFC_MAX_SYMBOL_LEN + 1];
+  unsigned pos = 0;
+  gfc_char_t c;
+
+  /* When we get here, we already parsed
+     !GCC$ ATTRIBUTES ATTRIBUTE_NAME
+     Now parse the arguments. These could be one of
+       "single_string_literal"
+       ( "str_literal_1" , "str_literal_2" )
+   */
+
+  gfc_gobble_whitespace ();
+
+  if (allow_multiple && gfc_match_char ('(') != MATCH_YES)
+    {
+      gfc_error ("expected '(' at %C");
+      return NULL_TREE;
+    }
+
+  if (require_string)
+    {
+      do {
+	if (pos)
+	  {
+	    if (!allow_multiple)
+	      {
+		gfc_error ("surplus argument at %C");
+		return NULL_TREE;
+	      }
+	    gfc_next_ascii_char (); /* Consume the comma.  */
+	  }
+	pos = 0;
+	gfc_gobble_whitespace ();
+	unsigned char num_quotes = 0;
+	do {
+	  c = gfc_next_char_literal (NONSTRING);
+	  if (c == '"')
+	    {
+	      num_quotes++;
+	      continue; /* Skip the quote */
+	    }
+	  name[pos++] = c;
+	  if (pos >= GFC_MAX_SYMBOL_LEN)
+	    {
+	      gfc_error ("attribute argument truncated at %C");
+	      return NULL_TREE;
+	    }
+	} while (num_quotes % 2 && gfc_match_eos () != MATCH_YES);
+	if (pos < 1)
+	  {
+	    gfc_error ("expected argument at %C");
+	    return NULL_TREE;
+	  }
+	if (num_quotes != 2)
+	  {
+	    gfc_error ("invalid string literal at %C");
+	    return NULL_TREE;
+	  }
+	name[pos] = '\0'; /* Redundant wrt build_string.  */
+	tree str = build_string (pos, name);
+	/* Compare with c-family/c-common.cc: fix_string_type.  */
+	tree i_type = build_index_type (size_int (pos));
+	tree a_type = build_array_type (char_type_node, i_type);
+	TREE_TYPE (str) = a_type;
+	TREE_READONLY (str) = 1;
+	TREE_STATIC (str) = 1;
+	attr_arg = build_tree_list (NULL_TREE, str);
+	attr_args = chainon (attr_args, attr_arg);
+
+	gfc_gobble_whitespace ();
+      } while (gfc_peek_ascii_char () == ',');
+    }
+
+  if (allow_multiple && gfc_match_char (')') != MATCH_YES)
+    {
+      gfc_error ("expected ')' at %C");
+      return NULL_TREE;
+    }
+
+  return attr_args;
+}
 
 const ext_attr_t ext_attr_list[] = {
   { "dllimport",    EXT_ATTR_DLLIMPORT,    "dllimport" },
@@ -11718,6 +11809,7 @@ const ext_attr_t ext_attr_list[] = {
   { "fastcall",     EXT_ATTR_FASTCALL,     "fastcall"  },
   { "no_arg_check", EXT_ATTR_NO_ARG_CHECK, NULL        },
   { "deprecated",   EXT_ATTR_DEPRECATED,   NULL	       },
+  { "target_clones",EXT_ATTR_TARGET_CLONES,NULL	       },
   { NULL,           EXT_ATTR_LAST,         NULL        }
 };
 
@@ -11743,6 +11835,7 @@ gfc_match_gcc_attributes (void)
   unsigned id;
   gfc_symbol *sym;
   match m;
+  tree attr_args = NULL_TREE;
 
   gfc_clear_attr (&attr);
   for(;;)
@@ -11761,6 +11854,15 @@ gfc_match_gcc_attributes (void)
 	  gfc_error ("Unknown attribute in !GCC$ ATTRIBUTES statement at %C");
 	  return MATCH_ERROR;
 	}
+      else if (id == EXT_ATTR_TARGET_CLONES)
+	{
+	  attr_args
+	    = gfc_match_gcc_attribute_args(true, true);
+	  if (attr_args != NULL_TREE)
+	    attr.ext_attr_args
+	      = chainon (attr.ext_attr_args,
+			 build_tree_list (get_identifier (name), attr_args));
+	}
 
       if (!gfc_add_ext_attribute (&attr, (ext_attr_id_t)id, &gfc_current_locus))
 	return MATCH_ERROR;
@@ -11793,6 +11895,8 @@ gfc_match_gcc_attributes (void)
 	return MATCH_ERROR;
 
       sym->attr.ext_attr |= attr.ext_attr;
+      sym->attr.ext_attr_args
+	= chainon (sym->attr.ext_attr_args, attr.ext_attr_args);
 
       if (gfc_match_eos () == MATCH_YES)
 	break;
diff --git a/gcc/fortran/f95-lang.cc b/gcc/fortran/f95-lang.cc
index a6750bea787..7154568aec5 100644
--- a/gcc/fortran/f95-lang.cc
+++ b/gcc/fortran/f95-lang.cc
@@ -97,6 +97,10 @@ static const struct attribute_spec gfc_attribute_table[] =
     gfc_handle_omp_declare_target_attribute, NULL },
   { "oacc function", 0, -1, true,  false, false, false,
     gfc_handle_omp_declare_target_attribute, NULL },
+  { "target",                 1, -1, true, false, false, false,
+			      gfc_handle_omp_declare_target_attribute, NULL },
+  { "target_clones",          1, -1, true, false, false, false,
+			      gfc_handle_omp_declare_target_attribute, NULL },
   { NULL,		  0, 0, false, false, false, false, NULL, NULL }
 };
 
diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index 6bd8800ecf8..ce0cb61e647 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -838,6 +838,7 @@ typedef enum
   EXT_ATTR_FASTCALL,
   EXT_ATTR_NO_ARG_CHECK,
   EXT_ATTR_DEPRECATED,
+  EXT_ATTR_TARGET_CLONES,
   EXT_ATTR_LAST, EXT_ATTR_NUM = EXT_ATTR_LAST
 }
 ext_attr_id_t;
@@ -1009,6 +1010,7 @@ typedef struct
 
   /* Attributes set by compiler extensions (!GCC$ ATTRIBUTES).  */
   unsigned ext_attr:EXT_ATTR_NUM;
+  tree ext_attr_args;
 
   /* The namespace where the attribute has been set.  */
   struct gfc_namespace *volatile_ns, *asynchronous_ns;
diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
index 4b4ecd528a7..06e4c8c00a1 100644
--- a/gcc/fortran/gfortran.texi
+++ b/gcc/fortran/gfortran.texi
@@ -3248,6 +3248,37 @@ deprecated procedure, variable or parameter; the warning can be suppressed
 with @option{-Wno-deprecated-declarations}.
 @end itemize
 
+@node target_clones (@var{options})
+
+Procedures can be annotated with a @code{target_clones} attribute to
+instruct the compiler to emit multiple versions of the procedure, each
+compiled with different target options in addition to those specified on
+the command line. The calling code remains exactly the same.
+Please refer to
+@ref{Top,,Common Function Attributes,gcc,Using the GNU Compiler Collection (GCC)}
+for details about the respective attribute.
+
+For example,
+
+@smallexample
+module mymod
+contains
+  subroutine sub1
+!GCC$ ATTRIBUTES target_clones("avx", "sse", "default") :: sub1
+  ! your code here
+  end
+end module mymod
+@end smallexample
+or,
+@smallexample
+module mymod
+contains
+  subroutine sub1
+!GCC$ ATTRIBUTES target_clones("power10","power9","power8","power7","default") :: sub1
+  ! your code here will be optimized for several PPC target architectures
+  end
+end module mymod
+@end smallexample
 
 The attributes are specified using the syntax
 
diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index 63515b9072a..24cbd4cda28 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -1447,6 +1447,9 @@ add_attributes_to_decl (symbol_attribute sym_attr, tree list)
 				 NULL_TREE);
 	list = chainon (list, attr);
       }
+  /* Add attribute args.  */
+  if (sym_attr.ext_attr_args != NULL_TREE)
+    list = chainon (list, sym_attr.ext_attr_args);
 
   tree clauses = NULL_TREE;
 
diff --git a/gcc/testsuite/gfortran.dg/attr_target_clones-1.F90 b/gcc/testsuite/gfortran.dg/attr_target_clones-1.F90
new file mode 100644
index 00000000000..724e58021fa
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/attr_target_clones-1.F90
@@ -0,0 +1,30 @@
+! { dg-require-ifunc "" }
+! { dg-options "-O1" }
+! { dg-additional-options "-fdump-tree-optimized" }
+! It seems arch defines are not defined?!
+! See fortran.cpp  FIXME: Pandora's Box
+! Ok, so enterprise-level bugfix:
+! { dg-additional-options "-D__i686__=1" { target { i?86-*-* } } }
+! { dg-additional-options "-D__x86_64__=1" { target { x86_64-*-* } } }
+! { dg-additional-options "-D__powerpc__=1" { target { powerpc*-*-* } } }
+! { dg-skip-if "test not yet implemented for target" { ! {i?86-*-* x86_64-*-* powerpc*-*-*} } }
+! Test __attribute__ ((target_clones ("foo", "bar")))
+!
+module m
+  implicit none
+contains
+  subroutine sub1()
+#if defined __i686__ || defined __x86_64__
+!GCC$ ATTRIBUTES target_clones("avx", "sse","default") :: sub1
+#elif defined __powerpc__
+!GCC$ ATTRIBUTES target_clones("power10", "power9","default") :: sub1
+#endif
+    print *, 4321
+  end
+end module m
+! { dg-final { scan-tree-dump-times {(?n)void \* __m_MOD_sub1\.resolver \(\)} 1 "optimized" } }
+! { dg-final { scan-tree-dump-times {(?n)void __m_MOD_sub1\.(?:avx|power10) \(\)} 1 "optimized" } }
+! { dg-final { scan-tree-dump-times {(?n)void __m_MOD_sub1\.(?:sse|power9) \(\)} 1 "optimized" } }
+! { dg-final { scan-tree-dump-times {(?n)void sub1 \(\)} 1 "optimized" } }
+!! and a non-assembly hint on the ifunc
+! { dg-final { scan-tree-dump-times {Function sub1 \(__m_MOD_sub1\.default,} 1 "optimized" } }
-- 
2.38.1