| Message ID | 20240419184317.2138890-4-qing.zhao@oracle.com |
|---|---|
| State | New |
| Headers | show |
| Series | Allow flexible array members in unions and alone in structures [PR53548] | expand |
On Fri, 19 Apr 2024, Qing Zhao wrote: > gcc/testsuite/ChangeLog: > > * gcc.dg/flex-array-in-union-1.c: New test. > * gcc.dg/flex-array-in-union-2.c: New test. There should also be a -pedantic-errors test that these constructs get errors with -pedantic-errors. The tests mix two cases: flexible arrays in unions, and flexible arrays on their own in structures. That means the test names are misleading; either they should be renamed, or the struct tests should be split out. Note that "no named members" also includes the case where there are unnamed bit-fields together with a flexible array member, so that should be tested as well. Since this patch series involves changes for both C and C++, it would be best for the tests to be c-c++-common tests. But if that's problematic for some reason - if there's still too much difference in behavior between C and C++ - then there should at least be tests for C++ that are as similar as possible to the tests for C.
> On Apr 23, 2024, at 14:53, Joseph Myers <josmyers@redhat.com> wrote: > > On Fri, 19 Apr 2024, Qing Zhao wrote: > >> gcc/testsuite/ChangeLog: >> >> * gcc.dg/flex-array-in-union-1.c: New test. >> * gcc.dg/flex-array-in-union-2.c: New test. > > There should also be a -pedantic-errors test that these constructs get > errors with -pedantic-errors. Okay, will add. > > The tests mix two cases: flexible arrays in unions, and flexible arrays on > their own in structures. That means the test names are misleading; either > they should be renamed, or the struct tests should be split out. Okay, will update this. > > Note that "no named members" also includes the case where there are > unnamed bit-fields together with a flexible array member, so that should > be tested as well. Will add such testing cases. > > Since this patch series involves changes for both C and C++, it would be > best for the tests to be c-c++-common tests. But if that's problematic > for some reason - if there's still too much difference in behavior between > C and C++ - then there should at least be tests for C++ that are as > similar as possible to the tests for C. I tried to put these two testing cases to c-c++-common, there were some inconsistent behavior I cannot resolve at that time, I will try to fix those issue or add C++ testing cases. Thanks for the review. Qing > > -- > Joseph S. Myers > josmyers@redhat.com >
diff --git a/gcc/testsuite/gcc.dg/flex-array-in-union-1.c b/gcc/testsuite/gcc.dg/flex-array-in-union-1.c new file mode 100644 index 000000000000..2a532d77c1dd --- /dev/null +++ b/gcc/testsuite/gcc.dg/flex-array-in-union-1.c @@ -0,0 +1,37 @@ +/* testing the correct usage of flexible array members in unions + and alone in structure. */ +/* { dg-do run} */ +/* { dg-options "-O2 -Wpedantic" } */ + +union with_fam_1 { + int a; + int b[]; /* { dg-warning "flexible array member in union is a GCC extension" } */ +}; + +union with_fam_2 { + char a; + int b[]; /* { dg-warning "flexible array member in union is a GCC extension" } */ +}; + +union with_fam_3 { + char a[]; /* { dg-warning " flexible array member in union is a GCC extension" } */ + int b[]; /* { dg-warning "flexible array member in union is a GCC extension" } */ +}; + +struct only_fam { + int b[]; /* { dg-warning "flexible array member in a struct with no named members is a GCC extension" } */ +}; + +int main () +{ + if (sizeof (union with_fam_1) != sizeof (int)) + __builtin_abort (); + if (sizeof (union with_fam_2) != __alignof__ (int)) + __builtin_abort (); + if (sizeof (union with_fam_3) != 0) + __builtin_abort (); + if (sizeof (struct only_fam) != 0) + __builtin_abort (); + return 0; +} + diff --git a/gcc/testsuite/gcc.dg/flex-array-in-union-2.c b/gcc/testsuite/gcc.dg/flex-array-in-union-2.c new file mode 100644 index 000000000000..130124bbe653 --- /dev/null +++ b/gcc/testsuite/gcc.dg/flex-array-in-union-2.c @@ -0,0 +1,42 @@ +/* testing the correct usage of flexible array members in unions + and alone in structure: initialization */ +/* { dg-do run} */ +/* { dg-options "-O2" } */ + +union with_fam_1 { + int a; + int b[]; +} with_fam_1_v = {.b = {1, 2, 3, 4}}; + +union with_fam_2 { + int a; + char b[]; +} with_fam_2_v = {.a = 0x1f2f3f4f}; + +union with_fam_3 { + char a[]; + int b[]; +} with_fam_3_v = {.b = {0x1f2f3f4f, 0x5f6f7f7f}}; + +struct only_fam { + int b[]; +} only_fam_v = {{7, 11}}; + +int main () +{ + if (with_fam_1_v.b[3] != 4 + || with_fam_1_v.b[0] != 1) + __builtin_abort (); + if (with_fam_2_v.b[3] != 0x1f + || with_fam_2_v.b[0] != 0x4f) + __builtin_abort (); + if (with_fam_3_v.a[0] != 0x4f + || with_fam_3_v.a[7] != 0x5f) + __builtin_abort (); + if (only_fam_v.b[0] != 7 + || only_fam_v.b[1] != 11) + __builtin_abort (); + + return 0; +} +