Re: [gold commit] PR 22914: Add support for .note.gnu.property sections

[Cary Coutant <ccoutant at gmail dot com>]

> I've committed this patch to add support for .note.gnu.property sections.

Follow-up patch to handle the ANDed feature bits correctly...

The original patch did not give the target enough hooks to discover
that an input object file does not have a particular property. For the
GNU_PROPERTY_X86_FEATURE_1_AND property, for example, where a missing
property should be assumed to be all zeroes, and ANDed with other
object modules, this is essential. We now store the target-specific
properties locally in the Target structure as native uint32_t fields,
then AND the per-object feature bits with the program's feature bits
when we're finished processing each input object file. The
target-specific properties are then added back to the output note
section during finalization.

-cary


2018-06-22  Cary Coutant  <ccoutant@gmail.com>

gold/
        PR gold/22914
        * layout.cc (read_sized_value): Fix spelling of section name.
        (Layout::layout_gnu_property): Call Sized_target::record_gnu_property
        for target-specific properties;
        don't store them with target-independent properties yet.
        (Layout::merge_gnu_properties): New method.
        (Layout::add_gnu_property): New method.
        (Layout::create_gnu_properties_note): Call target to finalize
        target-specific properties. Fix spelling of output section name.
        * layout.h (Layout::merge_gnu_properties): New method.
        (Layout::add_gnu_property): New method.
        * object.cc (Sized_relobj_file::do_layout): Call
        Layout::merge_gnu_properties.
        * target.h (Target::merge_gnu_property): Remove.
        (Target::finalize_gnu_properties): New method.
        (Target::do_merge_gnu_property): Move to Sized_target and rename.
        (Target::do_finalize_gnu_properties): New virtual method.
        (Sized_target::record_gnu_property): Moved and renamed from
        Target::do_merge_gnu_property.
        (Sized_target::merge_gnu_properties): New virtual method.
        * x86_64.cc (Target_x86_64::isa_1_used_, isa_1_needed_)
        (feature_1_, object_feature_1_, seen_first_object_): New data members.
        (Target_x86_64::do_merge_gnu_property): Rename to ...
        (Target_x86_64::record_gnu_property): ... this.  Save target-specific
        properties in Target class object.
        (Target_x86_64::merge_gnu_properties): New method.
        (add_property): New static inline function.
        (Target_x86_64::do_finalize_gnu_properties): New method.
        * testsuite/Makefile.am (gnu_property_test): Remove C source file;
        link directly without compiler driver.
        * testsuite/Makefile.in: Regenerate.
        * testsuite/gnu_property_a.S: Add _start.

Attachment: gnu-properties-2.patch
Description: Binary data