On 10/16/2015 09:34 PM, Martin Sebor wrote:
Thank you for the review. Attached is an updated patch that hopefully
addresses all your comments. I ran the check_GNU_style.sh script on
it to make sure I didn't miss something. I've also added replies to
a few of your comments below.
Ok, thanks. However - the logic around the context struct in the patch
still seems fairly impenetrable to me, and I've been wondering whether a
simpler approach wouldn't work just as well. I came up with the patch
below, which just passes a tree_code context to recursive invocations
and increasing the upper bound by one only if not in an ARRAY_REF or
COMPONENT_REF context.
As far as I can tell, this produces the same warnings on the testcase
(modulo differences in type printout), except for the final few FA5_7
testcases, which I had doubts about anyway:
typedef struct FA5_7 {
int i;
char a5_7 [5][7];
} FA5_7;
__builtin_offsetof (FA5_7, a5_7 [0][7]), // { dg-warning
"index" }
__builtin_offsetof (FA5_7, a5_7 [1][7]), // { dg-warning
"index" }
__builtin_offsetof (FA5_7, a5_7 [5][0]), // { dg-warning
"index" }
__builtin_offsetof (FA5_7, a5_7 [5][7]), // { dg-warning
"index" }
Why wouldn't at least the first two be convered by the
one-past-the-end-is-ok rule?
Bernd
Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c (revision 229049)
+++ gcc/c-family/c-common.c (working copy)
@@ -10589,11 +10589,11 @@ c_common_to_target_charset (HOST_WIDE_IN
traditional rendering of offsetof as a macro. Return the folded result. */
tree
-fold_offsetof_1 (tree expr)
+fold_offsetof_1 (tree expr, enum tree_code ctx)
{
tree base, off, t;
-
- switch (TREE_CODE (expr))
+ tree_code code = TREE_CODE (expr);
+ switch (code)
{
case ERROR_MARK:
return expr;
@@ -10617,7 +10617,7 @@ fold_offsetof_1 (tree expr)
return TREE_OPERAND (expr, 0);
case COMPONENT_REF:
- base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
+ base = fold_offsetof_1 (TREE_OPERAND (expr, 0), code);
if (base == error_mark_node)
return base;
@@ -10634,7 +10634,7 @@ fold_offsetof_1 (tree expr)
break;
case ARRAY_REF:
- base = fold_offsetof_1 (TREE_OPERAND (expr, 0));
+ base = fold_offsetof_1 (TREE_OPERAND (expr, 0), code);
if (base == error_mark_node)
return base;
@@ -10649,8 +10649,9 @@ fold_offsetof_1 (tree expr)
&& !tree_int_cst_equal (upbound,
TYPE_MAX_VALUE (TREE_TYPE (upbound))))
{
- upbound = size_binop (PLUS_EXPR, upbound,
- build_int_cst (TREE_TYPE (upbound), 1));
+ if (ctx != ARRAY_REF && ctx != COMPONENT_REF)
+ upbound = size_binop (PLUS_EXPR, upbound,
+ build_int_cst (TREE_TYPE (upbound), 1));
if (tree_int_cst_lt (upbound, t))
{
tree v;
Index: gcc/c-family/c-common.h
===================================================================
--- gcc/c-family/c-common.h (revision 229049)
+++ gcc/c-family/c-common.h (working copy)
@@ -1029,7 +1029,7 @@ extern bool c_dump_tree (void *, tree);
extern void verify_sequence_points (tree);
-extern tree fold_offsetof_1 (tree);
+extern tree fold_offsetof_1 (tree, tree_code ctx = ERROR_MARK);
extern tree fold_offsetof (tree);
/* Places where an lvalue, or modifiable lvalue, may be required.
