gcc/gcc41-builtin-va-arg-pack-len.patch

2007-09-11  Jakub Jelinek  <jakub@redhat.com>

	* builtins.def (BUILT_IN_VA_ARG_PACK_LEN): New builtin.
	* builtins.c (expand_builtin) <case BUILT_IN_VA_ARG_PACK_LEN>: Issue
	error if __builtin_va_arg_pack_len () wasn't optimized out during
	inlining.
	* tree-inline.c (copy_bb): Replace __builtin_va_arg_pack_len ()
	with the number of inline's anonymous arguments.
	* doc/extend.texi: Document __builtin_va_arg_pack_len ().

	* gcc.dg/va-arg-pack-len-1.c: New test.
	* g++.dg/va-arg-pack-len-1.C: New test.

--- gcc/builtins.def.jj	2007-09-06 10:19:24.000000000 +0200
+++ gcc/builtins.def	2007-09-14 21:07:41.000000000 +0200
@@ -666,6 +666,7 @@ DEF_GCC_BUILTIN        (BUILT_IN_VA_COPY
 DEF_GCC_BUILTIN        (BUILT_IN_VA_END, "va_end", BT_FN_VOID_VALIST_REF, ATTR_NULL)
 DEF_GCC_BUILTIN        (BUILT_IN_VA_START, "va_start", BT_FN_VOID_VALIST_REF_VAR, ATTR_NULL)
 DEF_GCC_BUILTIN        (BUILT_IN_VA_ARG_PACK, "va_arg_pack", BT_FN_INT, ATTR_PURE_NOTHROW_LIST)
+DEF_GCC_BUILTIN        (BUILT_IN_VA_ARG_PACK_LEN, "va_arg_pack_len", BT_FN_INT, ATTR_PURE_NOTHROW_LIST)
 DEF_EXT_LIB_BUILTIN    (BUILT_IN__EXIT, "_exit", BT_FN_VOID_INT, ATTR_NORETURN_NOTHROW_LIST)
 DEF_C99_BUILTIN        (BUILT_IN__EXIT2, "_Exit", BT_FN_VOID_INT, ATTR_NORETURN_NOTHROW_LIST)
 
--- gcc/builtins.c.jj	2007-09-06 11:04:56.000000000 +0200
+++ gcc/builtins.c	2007-09-14 21:07:41.000000000 +0200
@@ -5985,6 +5985,12 @@ expand_builtin (tree exp, rtx target, rt
       error ("invalid use of %<__builtin_va_arg_pack ()%>");
       return const0_rtx;
 
+    case BUILT_IN_VA_ARG_PACK_LEN:
+      /* All valid uses of __builtin_va_arg_pack_len () are removed during
+	 inlining.  */
+      error ("invalid use of %<__builtin_va_arg_pack_len ()%>");
+      return const0_rtx;
+
       /* Return the address of the first anonymous stack arg.  */
     case BUILT_IN_NEXT_ARG:
       if (fold_builtin_next_arg (arglist))
--- gcc/tree-inline.c.jj	2007-09-06 12:35:57.000000000 +0200
+++ gcc/tree-inline.c	2007-09-14 21:22:48.000000000 +0200
@@ -741,6 +741,37 @@ copy_bb (copy_body_data *id, basic_block
 	      *a = copy_list (arglist);
 	      CALL_EXPR_VA_ARG_PACK (call) = 0;
 	    }
+	  else if (call
+		   && id->call_expr
+		   && (decl = get_callee_fndecl (call))
+		   && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
+		   && DECL_FUNCTION_CODE (decl)
+		      == BUILT_IN_VA_ARG_PACK_LEN)
+	    {
+	      /* __builtin_va_arg_pack_len () should be replaced by
+		 the number of anonymous arguments.  */
+	      int nargs;
+	      tree count, *call_ptr, p, a;
+
+	      a = TREE_OPERAND (id->call_expr, 1);
+	      for (p = DECL_ARGUMENTS (id->src_fn); p; p = TREE_CHAIN (p))
+		a = TREE_CHAIN (a);
+
+              for (nargs = 0; a; a = TREE_CHAIN (a))
+		nargs++;
+
+	      count = build_int_cst (integer_type_node, nargs);
+	      call_ptr = &stmt;
+	      if (TREE_CODE (*call_ptr) == MODIFY_EXPR)
+		call_ptr = &TREE_OPERAND (*call_ptr, 1);
+	      if (TREE_CODE (*call_ptr) == WITH_SIZE_EXPR)
+		call_ptr = &TREE_OPERAND (*call_ptr, 0);
+	      gcc_assert (*call_ptr == call && call_ptr != &stmt);
+	      *call_ptr = count;
+	      update_stmt (stmt);
+	      call = NULL_TREE;
+	    }
+
 	  /* We're duplicating a CALL_EXPR.  Find any corresponding
 	     callgraph edges and update or duplicate them.  */
 	  if (call && (decl = get_callee_fndecl (call)))
--- gcc/doc/extend.texi.jj	2007-09-06 10:19:25.000000000 +0200
+++ gcc/doc/extend.texi	2007-09-14 21:07:41.000000000 +0200
@@ -578,6 +578,41 @@ myprintf (FILE *f, const char *format, .
 @end smallexample
 @end deftypefn
 
+@deftypefn {Built-in Function} __builtin_va_arg_pack_len ()
+This built-in function returns the number of anonymous arguments of
+an inline function.  It can be used only in inline functions which
+will be always inlined, never compiled as a separate function, such
+as those using @code{__attribute__ ((__always_inline__))} or
+@code{__attribute__ ((__gnu_inline__))} extern inline functions.
+For example following will do link or runtime checking of open
+arguments for optimized code:
+@smallexample
+#ifdef __OPTIMIZE__
+extern inline __attribute__((__gnu_inline__)) int
+myopen (const char *path, int oflag, ...)
+@{
+  if (__builtin_va_arg_pack_len () > 1)
+    warn_open_too_many_arguments ();
+
+  if (__builtin_constant_p (oflag))
+    @{
+      if ((oflag & O_CREAT) != 0 && __builtin_va_arg_pack_len () < 1)
+        @{
+          warn_open_missing_mode ();
+          return __open_2 (path, oflag);
+        @}
+      return open (path, oflag, __builtin_va_arg_pack ());
+    @}
+    
+  if (__builtin_va_arg_pack_len () < 1)
+    return __open_2 (path, oflag);
+
+  return open (path, oflag, __builtin_va_arg_pack ());
+@}
+#endif
+@end smallexample
+@end deftypefn
+
 @node Typeof
 @section Referring to a Type with @code{typeof}
 @findex typeof
--- gcc/testsuite/gcc.dg/va-arg-pack-len-1.c.jj	2007-09-14 21:07:41.000000000 +0200
+++ gcc/testsuite/gcc.dg/va-arg-pack-len-1.c	2007-09-14 21:07:41.000000000 +0200
@@ -0,0 +1,120 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+#include <stdarg.h>
+
+extern int warn_open_missing_mode (void);
+extern int warn_open_too_many_arguments (void);
+extern void abort (void);
+
+char expected_char;
+
+__attribute__((noinline)) int
+myopen2 (const char *path, int oflag)
+{
+  if (expected_char++ != path[0] || path[1] != '\0')
+    abort ();
+  switch (path[0])
+    {
+    case 'f':
+      if (oflag != 0x2)
+	abort ();
+      break;
+    case 'g':
+      if (oflag != 0x43)
+	abort ();
+      /* In real __open_2 this would terminate the program:
+	 open with O_CREAT without third argument.  */
+      return -6;
+    default:
+      abort ();
+    }
+  return 0;
+}
+
+__attribute__((noinline)) int
+myopenva (const char *path, int oflag, ...)
+{
+  int mode = 0;
+  va_list ap;
+  if ((oflag & 0x40) != 0)
+    {
+      va_start (ap, oflag);
+      mode = va_arg (ap, int);
+      va_end (ap);
+    }
+  if (expected_char++ != path[0] || path[1] != '\0')
+    abort ();
+  switch (path[0])
+    {
+    case 'a':
+      if (oflag != 0x43 || mode != 0644)
+	abort ();
+      break;
+    case 'b':
+      if (oflag != 0x3)
+	abort ();
+      break;
+    case 'c':
+      if (oflag != 0x2)
+	abort ();
+      break;
+    case 'd':
+      if (oflag != 0x43 || mode != 0600)
+	abort ();
+      break;
+    case 'e':
+      if (oflag != 0x3)
+	abort ();
+      break;
+    default:
+      abort ();
+    }
+  return 0;
+}
+
+extern inline __attribute__((always_inline, gnu_inline)) int
+myopen (const char *path, int oflag, ...)
+{
+  if (__builtin_va_arg_pack_len () > 1)
+    warn_open_too_many_arguments ();
+
+  if (__builtin_constant_p (oflag))
+    {
+      if ((oflag & 0x40) != 0 && __builtin_va_arg_pack_len () < 1)
+	{
+	  warn_open_missing_mode ();
+	  return myopen2 (path, oflag);
+	}
+      return myopenva (path, oflag, __builtin_va_arg_pack ());
+    }
+
+  if (__builtin_va_arg_pack_len () < 1)
+    return myopen2 (path, oflag);
+
+  return myopenva (path, oflag, __builtin_va_arg_pack ());
+}
+
+volatile int l0;
+
+int
+main (void)
+{
+  expected_char = 'a';
+  if (myopen ("a", 0x43, 0644))
+    abort ();
+  if (myopen ("b", 0x3, 0755))
+    abort ();
+  if (myopen ("c", 0x2))
+    abort ();
+  if (myopen ("d", l0 + 0x43, 0600))
+    abort ();
+  if (myopen ("e", l0 + 0x3, 0700))
+    abort ();
+  if (myopen ("f", l0 + 0x2))
+    abort ();
+  /* Invalid use of myopen, but only detectable at runtime.  */
+  if (myopen ("g", l0 + 0x43) != -6)
+    abort ();
+  return 0;
+}
--- gcc/testsuite/g++.dg/ext/va-arg-pack-len-1.C.jj	2007-09-14 21:07:41.000000000 +0200
+++ gcc/testsuite/g++.dg/ext/va-arg-pack-len-1.C	2007-09-14 21:07:41.000000000 +0200
@@ -0,0 +1,120 @@
+// { dg-do run }
+// { dg-options "-O2" }
+
+#include <stdarg.h>
+
+extern "C" int warn_open_missing_mode (void);
+extern "C" int warn_open_too_many_arguments (void);
+extern "C" void abort (void);
+
+char expected_char;
+
+__attribute__((noinline)) int
+myopen2 (const char *path, int oflag)
+{
+  if (expected_char++ != path[0] || path[1] != '\0')
+    abort ();
+  switch (path[0])
+    {
+    case 'f':
+      if (oflag != 0x2)
+	abort ();
+      break;
+    case 'g':
+      if (oflag != 0x43)
+	abort ();
+      // In real __open_2 this would terminate the program:
+      // open with O_CREAT without third argument.
+      return -6;
+    default:
+      abort ();
+    }
+  return 0;
+}
+
+__attribute__((noinline)) int
+myopenva (const char *path, int oflag, ...)
+{
+  int mode = 0;
+  va_list ap;
+  if ((oflag & 0x40) != 0)
+    {
+      va_start (ap, oflag);
+      mode = va_arg (ap, int);
+      va_end (ap);
+    }
+  if (expected_char++ != path[0] || path[1] != '\0')
+    abort ();
+  switch (path[0])
+    {
+    case 'a':
+      if (oflag != 0x43 || mode != 0644)
+	abort ();
+      break;
+    case 'b':
+      if (oflag != 0x3)
+	abort ();
+      break;
+    case 'c':
+      if (oflag != 0x2)
+	abort ();
+      break;
+    case 'd':
+      if (oflag != 0x43 || mode != 0600)
+	abort ();
+      break;
+    case 'e':
+      if (oflag != 0x3)
+	abort ();
+      break;
+    default:
+      abort ();
+    }
+  return 0;
+}
+
+extern inline __attribute__((always_inline, gnu_inline)) int
+myopen (const char *path, int oflag, ...)
+{
+  if (__builtin_va_arg_pack_len () > 1)
+    warn_open_too_many_arguments ();
+
+  if (__builtin_constant_p (oflag))
+    {
+      if ((oflag & 0x40) != 0 && __builtin_va_arg_pack_len () < 1)
+	{
+	  warn_open_missing_mode ();
+	  return myopen2 (path, oflag);
+	}
+      return myopenva (path, oflag, __builtin_va_arg_pack ());
+    }
+
+  if (__builtin_va_arg_pack_len () < 1)
+    return myopen2 (path, oflag);
+
+  return myopenva (path, oflag, __builtin_va_arg_pack ());
+}
+
+volatile int l0;
+
+int
+main (void)
+{
+  expected_char = 'a';
+  if (myopen ("a", 0x43, 0644))
+    abort ();
+  if (myopen ("b", 0x3, 0755))
+    abort ();
+  if (myopen ("c", 0x2))
+    abort ();
+  if (myopen ("d", l0 + 0x43, 0600))
+    abort ();
+  if (myopen ("e", l0 + 0x3, 0700))
+    abort ();
+  if (myopen ("f", l0 + 0x2))
+    abort ();
+  // Invalid use of myopen, but only detectable at runtime.
+  if (myopen ("g", l0 + 0x43) != -6)
+    abort ();
+  return 0;
+}