Fortran: Add !GCC$ attributes NOINLINE,NORETURN,WEAK

gcc/fortran/ChangeLog:

	* decl.cc: Add EXT_ATTR_NOINLINE, EXT_ATTR_NORETURN, EXT_ATTR_WEAK.
	* gfortran.h (ext_attr_id_t): Ditto.
	* gfortran.texi (GCC$ ATTRIBUTES): Document them.
	* trans-decl.cc (build_function_decl): Apply them.

gcc/testsuite/ChangeLog:

	* gfortran.dg/noinline.f90: New test.
	* gfortran.dg/noreturn-1.f90: New test.
	* gfortran.dg/noreturn-2.f90: New test.
	* gfortran.dg/noreturn-3.f90: New test.
	* gfortran.dg/noreturn-4.f90: New test.
	* gfortran.dg/noreturn-5.f90: New test.
	* gfortran.dg/weak-1.f90: New test.

Signed-off-by: Rimvydas Jasinskas <rimvydas.jas@gmail.com>

4 files changed, 25 insertions, 1 deletions

diff --git a/gcc/fortran/decl.cc b/gcc/fortran/decl.cc
index 27b728f..eec0314 100644
--- a/gcc/fortran/decl.cc
+++ b/gcc/fortran/decl.cc
@@ -11732,6 +11732,9 @@ 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	       },
+  { "noinline",     EXT_ATTR_NOINLINE,     NULL	       },
+  { "noreturn",     EXT_ATTR_NORETURN,     NULL	       },
+  { "weak",	    EXT_ATTR_WEAK,	   NULL	       },
   { NULL,           EXT_ATTR_LAST,         NULL        }
 };
 
diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index 9884a55..a893ee0 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -838,6 +838,9 @@ typedef enum
   EXT_ATTR_FASTCALL,
   EXT_ATTR_NO_ARG_CHECK,
   EXT_ATTR_DEPRECATED,
+  EXT_ATTR_NOINLINE,
+  EXT_ATTR_NORETURN,
+  EXT_ATTR_WEAK,
   EXT_ATTR_LAST, EXT_ATTR_NUM = EXT_ATTR_LAST
 }
 ext_attr_id_t;
diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
index c3813d0..c483e13 100644
--- a/gcc/fortran/gfortran.texi
+++ b/gcc/fortran/gfortran.texi
@@ -3246,6 +3246,13 @@ requires an explicit interface.
 @item @code{DEPRECATED} -- print a warning when using a such-tagged
 deprecated procedure, variable or parameter; the warning can be suppressed
 with @option{-Wno-deprecated-declarations}.
+@item @code{NOINLINE} -- prevent inlining given function.
+@item @code{NORETURN} -- add a hint that a given function cannot return.
+@item @code{WEAK} -- emit the declaration of an external symbol as a weak
+symbol rather than a global.  This is primarily useful in defining library
+functions that can be overridden in user code, though it can also be used with
+non-function declarations.  The overriding symbol must have the same type as
+the weak symbol.
 @end itemize
 
 
diff --git a/gcc/fortran/trans-decl.cc b/gcc/fortran/trans-decl.cc
index f7a7ff6..ff64588 100644
--- a/gcc/fortran/trans-decl.cc
+++ b/gcc/fortran/trans-decl.cc
@@ -2338,7 +2338,7 @@ module_sym:
     }
 
   /* Mark non-returning functions.  */
-  if (sym->attr.noreturn)
+  if (sym->attr.noreturn || sym->attr.ext_attr & (1 << EXT_ATTR_NORETURN))
       TREE_THIS_VOLATILE(fndecl) = 1;
 
   sym->backend_decl = fndecl;
@@ -2482,6 +2482,17 @@ build_function_decl (gfc_symbol * sym, bool global)
       TREE_SIDE_EFFECTS (fndecl) = 0;
     }
 
+  /* Mark noinline functions.  */
+  if (attr.ext_attr & (1 << EXT_ATTR_NOINLINE))
+    DECL_UNINLINABLE (fndecl) = 1;
+
+  /* Mark noreturn functions.  */
+  if (attr.ext_attr & (1 << EXT_ATTR_NORETURN))
+    TREE_THIS_VOLATILE (fndecl) = 1;
+
+  /* Mark weak functions.  */
+  if (attr.ext_attr & (1 << EXT_ATTR_WEAK))
+    declare_weak (fndecl);
 
   /* Layout the function declaration and put it in the binding level
      of the current function.  */