Xi Ruoyao via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> We are comparing enum values (in wide_int) to check ODR violation.
> However, if we compare two wide_int values with different precision,
> we'll trigger an assert, leading to ICE. With enum-base introduced
> in C++11, it's easy to sink into this situation.
>
> To fix the issue, we need to explicitly check this kind of mismatch,
> and emit a proper warning message if there is such one.
>
> Bootstrapped & regtested on x86_64-linux-gnu. Ok for trunk?
>
> gcc/
>
> PR ipa/101396
> * ipa-devirt.c (ipa_odr_read_section): Compare the precision of
> enum values, and emit a warning if they mismatch.
OK, thanks.
Richard
> gcc/testsuite/
>
> PR ipa/101396
> * g++.dg/lto/pr101396_0.C: New test.
> * g++.dg/lto/pr101396_1.C: New test.
> ---
> gcc/ipa-devirt.c | 9 +++++++++
> gcc/testsuite/g++.dg/lto/pr101396_0.C | 12 ++++++++++++
> gcc/testsuite/g++.dg/lto/pr101396_1.C | 10 ++++++++++
> 3 files changed, 31 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/lto/pr101396_0.C
> create mode 100644 gcc/testsuite/g++.dg/lto/pr101396_1.C
>
> diff --git a/gcc/ipa-devirt.c b/gcc/ipa-devirt.c
> index 8cd1100aba9..8deec75b2df 100644
> --- a/gcc/ipa-devirt.c
> +++ b/gcc/ipa-devirt.c
> @@ -4193,6 +4193,8 @@ ipa_odr_read_section (struct lto_file_decl_data
> *file_data, const char *data,
> if (do_warning != -1 || j >= this_enum.vals.length ())
> continue;
> if (strcmp (id, this_enum.vals[j].name)
> + || (val.get_precision() !=
> + this_enum.vals[j].val.get_precision())
> || val != this_enum.vals[j].val)
> {
> warn_name = xstrdup (id);
> @@ -4260,6 +4262,13 @@ ipa_odr_read_section (struct lto_file_decl_data
> *file_data, const char *data,
> "name %qs differs from name %qs defined"
> " in another translation unit",
> this_enum.vals[j].name, warn_name);
> + else if (this_enum.vals[j].val.get_precision() !=
> + warn_value.get_precision())
> + inform (this_enum.vals[j].locus,
> + "name %qs is defined as %u-bit while another "
> + "translation unit defines it as %u-bit",
> + warn_name, this_enum.vals[j].val.get_precision(),
> + warn_value.get_precision());
> /* FIXME: In case there is easy way to print wide_ints,
> perhaps we could do it here instead of overflow check. */
> else if (wi::fits_shwi_p (this_enum.vals[j].val)
> diff --git a/gcc/testsuite/g++.dg/lto/pr101396_0.C
> b/gcc/testsuite/g++.dg/lto/pr101396_0.C
> new file mode 100644
> index 00000000000..b7a2947a880
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/lto/pr101396_0.C
> @@ -0,0 +1,12 @@
> +/* { dg-lto-do link } */
> +
> +enum A : __UINT32_TYPE__ { // { dg-lto-warning "6: type 'A' violates the
> C\\+\\+ One Definition Rule" }
> + a, // { dg-lto-note "3: name 'a' is defined as 32-bit while another
> translation unit defines it as 64-bit" }
> + b,
> + c
> +};
> +
> +int main()
> +{
> + return (int) A::a;
> +}
> diff --git a/gcc/testsuite/g++.dg/lto/pr101396_1.C
> b/gcc/testsuite/g++.dg/lto/pr101396_1.C
> new file mode 100644
> index 00000000000..a6d032d694d
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/lto/pr101396_1.C
> @@ -0,0 +1,10 @@
> +enum A : __UINT64_TYPE__ { // { dg-lto-note "6: an enum with different value
> name is defined in another translation unit" }
> + a, // { dg-lto-note "3: mismatching definition" }
> + b,
> + c
> +};
> +
> +int f(enum A x)
> +{
> + return (int) x;
> +}
