builtin-attrs.def (ATTR_NOTHROW_SENTINEL_1): New.

	* builtin-attrs.def (ATTR_NOTHROW_SENTINEL_1): New.
	* builtins.def (BUILT_IN_EXECLE): Set ATTR_NOTHROW_SENTINEL_1.
	* c-common.c (c_common_attribute_table): Accept parameters to
	sentinel attribute.
	(check_function_sentinel, handle_sentinel_attribute): Likewise.
	* doc/extend.texi: Update accordingly.

testsuite:
	* gcc.dg/format/sentinel-1.c: Update for parameter option.

From-SVN: r87098

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 96da912b162d6da9ef70071afad92820099f3bcb..88486b14796ac64ecb80b5042189afd7e88d4266 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,12 @@
+2004-09-04  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+       * builtin-attrs.def (ATTR_NOTHROW_SENTINEL_1): New.
+       * builtins.def (BUILT_IN_EXECLE): Set ATTR_NOTHROW_SENTINEL_1.
+       * c-common.c (c_common_attribute_table): Accept parameters to
+       sentinel attribute.
+       (check_function_sentinel, handle_sentinel_attribute): Likewise.
+       * doc/extend.texi: Update accordingly.
+
 2004-09-04  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
        * builtin-attrs.def (ATTR_SENTINEL, ATTR_SENTINEL_NOTHROW_LIST):

diff --git a/gcc/builtin-attrs.def b/gcc/builtin-attrs.def
index 67cf193e4fd1c1c4a214ca3d40f550c07a1b5498..f376f5571b553dace92cfc17a049eacc8f0a8a36 100644 (file)
--- a/gcc/builtin-attrs.def
+++ b/gcc/builtin-attrs.def
@@ -101,6 +101,8 @@ DEF_ATTR_TREE_LIST (ATTR_MALLOC_NOTHROW_LIST, ATTR_MALLOC,  \
 DEF_ATTR_TREE_LIST (ATTR_SENTINEL_NOTHROW_LIST, ATTR_SENTINEL, \
                        ATTR_NULL, ATTR_NOTHROW_LIST)
 
+DEF_ATTR_TREE_LIST (ATTR_NOTHROW_SENTINEL_1, ATTR_SENTINEL, ATTR_LIST_1, \
+                       ATTR_NOTHROW_LIST)
 DEF_ATTR_TREE_LIST (ATTR_NOTHROW_NONNULL_1, ATTR_NONNULL, ATTR_LIST_1, \
                        ATTR_NOTHROW_LIST)
 DEF_ATTR_TREE_LIST (ATTR_NOTHROW_NONNULL_2, ATTR_NONNULL, ATTR_LIST_2, \

diff --git a/gcc/builtins.def b/gcc/builtins.def
index e89509fcebfa3a4cf5715095c9472b162b95dd8c..1bdc8aa79ee565d30bb852fcd007b381d241c6b8 100644 (file)
--- a/gcc/builtins.def
+++ b/gcc/builtins.def
@@ -556,7 +556,7 @@ DEF_GCC_BUILTIN        (BUILT_IN_EH_RETURN, "eh_return", BT_FN_VOID_PTRMODE_PTR,
 DEF_GCC_BUILTIN        (BUILT_IN_EH_RETURN_DATA_REGNO, "eh_return_data_regno", BT_FN_INT_INT, ATTR_NULL)
 DEF_EXT_LIB_BUILTIN        (BUILT_IN_EXECL, "execl", BT_FN_INT_CONST_STRING_CONST_STRING_VAR, ATTR_SENTINEL_NOTHROW_LIST)
 DEF_EXT_LIB_BUILTIN        (BUILT_IN_EXECLP, "execlp", BT_FN_INT_CONST_STRING_CONST_STRING_VAR, ATTR_SENTINEL_NOTHROW_LIST)
-DEF_EXT_LIB_BUILTIN        (BUILT_IN_EXECLE, "execle", BT_FN_INT_CONST_STRING_CONST_STRING_VAR, ATTR_NOTHROW_LIST)
+DEF_EXT_LIB_BUILTIN        (BUILT_IN_EXECLE, "execle", BT_FN_INT_CONST_STRING_CONST_STRING_VAR, ATTR_NOTHROW_SENTINEL_1)
 DEF_EXT_LIB_BUILTIN        (BUILT_IN_EXECV, "execv", BT_FN_INT_CONST_STRING_PTR_CONST_STRING, ATTR_NOTHROW_LIST)
 DEF_EXT_LIB_BUILTIN        (BUILT_IN_EXECVP, "execvp", BT_FN_INT_CONST_STRING_PTR_CONST_STRING, ATTR_NOTHROW_LIST)
 DEF_EXT_LIB_BUILTIN        (BUILT_IN_EXECVE, "execve", BT_FN_INT_CONST_STRING_PTR_CONST_STRING_PTR_CONST_STRING, ATTR_NOTHROW_LIST)

diff --git a/gcc/c-common.c b/gcc/c-common.c
index 3af1e6408ed0391406cf10b30488018397aa535d..1a105701eb08f0f781b6d7e2670876b415bdc50c 100644 (file)
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -636,7 +636,7 @@ const struct attribute_spec c_common_attribute_table[] =
                              handle_cleanup_attribute },
   { "warn_unused_result",     0, 0, false, true, true,
                              handle_warn_unused_result_attribute },
-  { "sentinel",               0, 0, false, true, true,
+  { "sentinel",               0, 1, false, true, true,
                              handle_sentinel_attribute },
   { NULL,                     0, 0, false, false, false, NULL }
 };
@@ -5047,7 +5047,8 @@ check_function_nonnull (tree attrs, tree params)
     }
 }
 
-/* Check the last argument of a function call is (pointer)0.  */
+/* Check that the Nth argument of a function call (counting backwards
+   from the end) is a (pointer)0.  */
 
 static void
 check_function_sentinel (tree attrs, tree params)
@@ -5060,11 +5061,40 @@ check_function_sentinel (tree attrs, tree params)
        warning ("missing sentinel in function call");
       else
         {
-         /* Find the last parameter.  */
-         while (TREE_CHAIN (params))
-           params = TREE_CHAIN (params);
-         if (!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (params)))
-             || !integer_zerop (TREE_VALUE (params)))
+         tree sentinel, end;
+         unsigned pos = 0;
+         
+         if (TREE_VALUE (attr))
+           {
+             tree p = TREE_VALUE (TREE_VALUE (attr));
+             STRIP_NOPS (p);
+             pos = TREE_INT_CST_LOW (p);
+           }
+
+         sentinel = end = params;
+
+         /* Advance `end' ahead of `sentinel' by `pos' positions.  */
+         while (pos > 0 && TREE_CHAIN (end))
+           {
+             pos--;
+             end = TREE_CHAIN (end);
+           }
+         if (pos > 0)
+           {
+             warning ("not enough arguments to fit a sentinel");
+             return;
+           }
+
+         /* Now advance both until we find the last parameter.  */
+         while (TREE_CHAIN (end))
+           {
+             end = TREE_CHAIN (end);
+             sentinel = TREE_CHAIN (sentinel);
+           }
+
+         /* Validate the sentinel.  */
+         if (!POINTER_TYPE_P (TREE_TYPE (TREE_VALUE (sentinel)))
+             || !integer_zerop (TREE_VALUE (sentinel)))
            warning ("missing sentinel in function call");
        }
     }
@@ -5215,8 +5245,7 @@ handle_warn_unused_result_attribute (tree *node, tree name,
 /* Handle a "sentinel" attribute.  */
 
 static tree
-handle_sentinel_attribute (tree *node, tree name,
-                          tree ARG_UNUSED (args),
+handle_sentinel_attribute (tree *node, tree name, tree args,
                           int ARG_UNUSED (flags), bool *no_add_attrs)
 {
   tree params = TYPE_ARG_TYPES (*node);
@@ -5226,17 +5255,38 @@ handle_sentinel_attribute (tree *node, tree name,
       warning ("`%s' attribute requires prototypes with named arguments",
                IDENTIFIER_POINTER (name));
       *no_add_attrs = true;
-      return NULL_TREE;
     }
+  else
+    {
+      while (TREE_CHAIN (params))
+       params = TREE_CHAIN (params);
 
-  while (TREE_CHAIN (params))
-    params = TREE_CHAIN (params);
-
-  if (VOID_TYPE_P (TREE_VALUE (params)))
+      if (VOID_TYPE_P (TREE_VALUE (params)))
+        {
+         warning ("`%s' attribute only applies to variadic functions",
+                  IDENTIFIER_POINTER (name));
+         *no_add_attrs = true;
+       }
+    }
+  
+  if (args)
     {
-      warning ("`%s' attribute only applies to variadic functions",
-              IDENTIFIER_POINTER (name));
-      *no_add_attrs = true;
+      tree position = TREE_VALUE (args);
+
+      STRIP_NOPS (position);
+      if (TREE_CODE (position) != INTEGER_CST)
+        {
+         warning ("requested position is not an integer constant");
+         *no_add_attrs = true;
+       }
+      else
+        {
+         if (tree_int_cst_lt (position, integer_zero_node))
+           {
+             warning ("requested position is less than zero");
+             *no_add_attrs = true;
+           }
+       }
     }
   
   return NULL_TREE;

diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi
index 4c27320f2b95195b0bfa112d133b8bc328a04033..bbde788ee5cd82dade7ec049f80bb9cdca63d6d0 100644 (file)
--- a/gcc/doc/extend.texi
+++ b/gcc/doc/extend.texi
@@ -2113,15 +2113,30 @@ section, consider using the facilities of the linker instead.
 
 @item sentinel
 @cindex @code{sentinel} function attribute
-This function attribute ensures that the last parameter in a function
-call is an explicit @code{NULL}.  The attribute is only valid on
-variadic functions.  For example the attribute is automatically set for
-the built-in functions @code{execl} and @code{execlp} where @code{NULL}
-is the marker for argument list termination.  A valid @code{NULL} in
-this context is defined as zero with any pointer type.  If your system
-defines the @code{NULL} macro with an integer type then you need to add
-an explicit cast.  The warnings for missing or incorrect sentinels are
-enabled with @option{-Wformat}.
+This function attribute ensures that a parameter in a function call is
+an explicit @code{NULL}.  The attribute is only valid on variadic
+functions.  By default, the sentinel is located at position zero, the
+last parameter of the function call.  If an optional integer position
+argument P is supplied to the attribute, the sentinel must be located at
+position P counting backwards from the end of the argument list.
+
+@smallexample
+__attribute__ ((sentinel))
+is equivalent to
+__attribute__ ((sentinel(0)))
+@end smallexample
+
+The attribute is automatically set with a position of 0 for the built-in
+functions @code{execl} and @code{execlp}.  The built-in function
+@code{execle} has the attribute set set with a position of 1.
+
+A valid @code{NULL} in this context is defined as zero with any pointer
+type.  If your system defines the @code{NULL} macro with an integer type
+then you need to add an explicit cast.  GCC replaces @code{stddef.h}
+with a copy that redefines NULL appropriately.
+
+The warnings for missing or incorrect sentinels are enabled with
+@option{-Wformat}.
 
 @item short_call
 See long_call/short_call.

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4fb58cb251b55463f57303930ada633cb3d8a5f8..01e0815f4627ed65fb05f2203b8f4206dc7fb1f0 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2004-09-04  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
+
+       * gcc.dg/format/sentinel-1.c: Update for parameter option.
+
 2004-09-04  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
        * gcc.dg/format/sentinel-1.c: New test.

diff --git a/gcc/testsuite/gcc.dg/format/sentinel-1.c b/gcc/testsuite/gcc.dg/format/sentinel-1.c
index e1e127dca38e9dcc1836e1290b978906a7ecbc8c..12915b7dc5a3a8cb0524c9dae60a1ad11845e5db 100644 (file)
--- a/gcc/testsuite/gcc.dg/format/sentinel-1.c
+++ b/gcc/testsuite/gcc.dg/format/sentinel-1.c
@@ -7,6 +7,8 @@
 
 extern int execl (const char *, const char *, ...);
 extern int execlp (const char *, const char *, ...);
+extern int execle (const char *, const char *, ...);
+extern char *envp[];
 
 #define ATTR __attribute__ ((__sentinel__))
 
@@ -16,6 +18,12 @@ extern void foo1 (const char *, ...) ATTR;
 extern void foo2 (...) ATTR; /* { dg-error "ISO C requires|named arguments" "sentinel" } */
 extern void foo3 () ATTR; /* { dg-warning "named arguments" "sentinel" } */
 extern void foo4 (const char *, int) ATTR; /* { dg-warning "variadic functions" "sentinel" } */
+extern void foo5 (const char *, ...) __attribute__ ((__sentinel__(1)));
+extern void foo6 (const char *, ...) __attribute__ ((__sentinel__(5)));
+extern void foo7 (const char *, ...) __attribute__ ((__sentinel__(0)));
+extern void foo8 (const char *, ...) __attribute__ ((__sentinel__("a"))); /* { dg-warning "not an integer constant" "sentinel" } */
+extern void foo9 (const char *, ...) __attribute__ ((__sentinel__(-1))); /* { dg-warning "less than zero" "sentinel" } */
+extern void foo10 (const char *, ...) __attribute__ ((__sentinel__(1,3))); /* { dg-error "wrong number of arguments" "sentinel" } */
 
 extern void bar(void)
 {
@@ -27,6 +35,23 @@ extern void bar(void)
   foo1 ("a", NULL, 1); /* { dg-warning "missing sentinel" "sentinel" } */
   foo1 ("a", NULL);
 
+  foo5 ("a", 1, 2, 3, NULL); /* { dg-warning "missing sentinel" "sentinel" } */
+  foo5 ("a", 1, 2, NULL, 3);
+  foo5 ("a", 1, NULL, 2, 3); /* { dg-warning "missing sentinel" "sentinel" } */
+  foo5 ("a", NULL, 1, 2, 3); /* { dg-warning "missing sentinel" "sentinel" } */
+  foo5 ("a", 0, 1, 2, 3); /* { dg-warning "missing sentinel" "sentinel" } */
+
+  foo6 ("a", 1, NULL); /* { dg-warning "not enough arguments" "sentinel" } */
+  foo6 ("a", 1, NULL, 2); /* { dg-warning "not enough arguments" "sentinel" } */
+  foo6 ("a", 1, NULL, 2, 3); /* { dg-warning "not enough arguments" "sentinel" } */
+  foo6 ("a", NULL, 1, 2, 3); /* { dg-warning "not enough arguments" "sentinel" } */
+  foo6 ("a", NULL, 1, 2, 3, 4); /* { dg-warning "missing sentinel" "sentinel" } */
+  foo6 ("a", NULL, 1, 2, 3, 4, 5);
+  foo6 ("a", 0, 1, 2, 3, 4, 5); /* { dg-warning "missing sentinel" "sentinel" } */
+  foo6 ("a", NULL, 1, 2, 3, 4, 5, 6); /* { dg-warning "missing sentinel" "sentinel" } */
+
+  foo7 ("a", 1, 2, 3, NULL);
+
   execl ("/bin/ls", "-aFC"); /* { dg-warning "missing sentinel" "sentinel" } */
   execl ("/bin/ls", "-aFC", 0); /* { dg-warning "missing sentinel" "sentinel" } */
   execl ("/bin/ls", "-aFC", NULL);
@@ -34,4 +59,8 @@ extern void bar(void)
   execlp ("ls", "-aFC"); /* { dg-warning "missing sentinel" "sentinel" } */
   execlp ("ls", "-aFC", 0); /* { dg-warning "missing sentinel" "sentinel" } */
   execlp ("ls", "-aFC", NULL);
+
+  execle ("ls", "-aFC", ".", envp); /* { dg-warning "missing sentinel" "sentinel" } */
+  execle ("ls", "-aFC", ".", 0, envp); /* { dg-warning "missing sentinel" "sentinel" } */
+  execle ("ls", "-aFC", ".", NULL, envp);
 }