On 5/16/22 03:16, Richard Biener wrote:
The following tries to correct get_origin_and_offset_r not handling
non-constant sizes of array elements in ARRAY_REFs and non-constant
offsets of COMPONENT_REFs. It isn't exactly clear how such failures
should be treated in this API and existing handling isn't consistent
here either. The following applies two different variants, treating
non-constant array sizes like non-constant array indices and
treating non-constant offsets of COMPONENT_REFs by terminating
the recursion (not sure what that means to the callers).
Basically the code failed to use component_ref_field_offset and
array_ref_element_size and instead relies on inappropriate
helpers (that shouldn't exist in the first place ...). The code
is also not safe-guarded against overflows in the final offset/size
computations but I'm not trying to rectify that.
Martin - can you comment on how the API should handle such
situations?
It looks like the -Wrestrict warning here ignores offsets equal to
HOST_WIDE_INT_MIN so presumably setting dst_offset (via *fldoff) to
that should avoid it. Or maybe to HWI_MAX as it does for variable
offsets.
It also looks like the function only handles constant offsets and
sizes, and I have a vague recollection of enhancing it to work with
ranges. That should avoid the overflow problem too.
Martin
Bootstrapped and tested on x86_64-unknown-linux-gnu.
OK for trunk and branches?
Thanks,
Richard.
2022-05-16 Richard Biener <rguent...@suse.de>
PR middle-end/105604
* gimple-ssa-sprintf.cc (get_origin_and_offset_r):
Handle non-constant ARRAY_REF element size and non-constant
COMPONENT_REF field offset.
* gcc.dg/torture/pr105604.c: New testcase.
---
gcc/gimple-ssa-sprintf.cc | 14 +++++++++++---
gcc/testsuite/gcc.dg/torture/pr105604.c | 24 ++++++++++++++++++++++++
2 files changed, 35 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr105604.c
diff --git a/gcc/gimple-ssa-sprintf.cc b/gcc/gimple-ssa-sprintf.cc
index c93f12f90b5..14e215ce69c 100644
--- a/gcc/gimple-ssa-sprintf.cc
+++ b/gcc/gimple-ssa-sprintf.cc
@@ -2312,14 +2312,16 @@ get_origin_and_offset_r (tree x, HOST_WIDE_INT *fldoff,
HOST_WIDE_INT *fldsize,
HOST_WIDE_INT idx = (tree_fits_uhwi_p (offset)
? tree_to_uhwi (offset) : HOST_WIDE_INT_MAX);
+ tree elsz = array_ref_element_size (x);
tree eltype = TREE_TYPE (x);
if (TREE_CODE (eltype) == INTEGER_TYPE)
{
if (off)
*off = idx;
}
- else if (idx < HOST_WIDE_INT_MAX)
- *fldoff += idx * int_size_in_bytes (eltype);
+ else if (idx < HOST_WIDE_INT_MAX
+ && tree_fits_shwi_p (elsz))
+ *fldoff += idx * tree_to_shwi (elsz);
else
*fldoff = idx;
@@ -2350,8 +2352,14 @@ get_origin_and_offset_r (tree x, HOST_WIDE_INT *fldoff, HOST_WIDE_INT *fldsize,
case COMPONENT_REF:
{
+ tree foff = component_ref_field_offset (x);
tree fld = TREE_OPERAND (x, 1);
- *fldoff += int_byte_position (fld);
+ if (!tree_fits_shwi_p (foff)
+ || !tree_fits_shwi_p (DECL_FIELD_BIT_OFFSET (fld)))
+ return x;
+ *fldoff += (tree_to_shwi (foff)
+ + (tree_to_shwi (DECL_FIELD_BIT_OFFSET (fld))
+ / BITS_PER_UNIT));
get_origin_and_offset_r (fld, fldoff, fldsize, off);
x = TREE_OPERAND (x, 0);
diff --git a/gcc/testsuite/gcc.dg/torture/pr105604.c
b/gcc/testsuite/gcc.dg/torture/pr105604.c
new file mode 100644
index 00000000000..b002251df10
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr105604.c
@@ -0,0 +1,24 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-Wall" } */
+
+struct {
+ long users;
+ long size;
+ char *data;
+} * main_trans;
+void *main___trans_tmp_1;
+int sprintf(char *, char *, ...);
+int main() {
+ int users = 0;
+ struct {
+ long users;
+ long size;
+ char *data;
+ int links[users];
+ char buf[];
+ } *trans = trans;
+ trans->data = trans->buf;
+ main___trans_tmp_1 = trans;
+ main_trans = main___trans_tmp_1;
+ sprintf(main_trans->data, "test");
+}
