This is the mail archive of the gcc-patches@gcc.gnu.org mailing list for the GCC project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

[PATCH] DW_OP_GNU_implicit_pointer support


Hi!

This patch implements the GCC side of implicit pointer DWARF extension,
which allows optimized out pointers to be partially usable in debug info
consumers.
For details see the proposal Roland sent last night to Dwarf-Discuss
mailing list.  In short, the user can dereference such pointers in the
debugger, even when what they are pointing to doesn't live in memory (can
live in registers, or have constant values, or piecewise mix thereof),
can query their type (that was possible before already), but can't
print their value.  In cc1plus .debug_info/.debug_loc this
DW_OP_GNU_implicit_pointer op is used over 22000 times.

Ok for trunk (assuming nobody suggests some encoding change on Dwarf-Discuss
within a few days - as DWARF 5 is probably years away, we want to implement
this as a GNU vendor extension and if it is accepted for DWARF 5, switch
over to the standard op when DWARF 5 is drafted or released, but if possible
we'd like to just switch to a different op code instead of switching
semantics as well)?

	Jakub

Attachment: Y675d
Description: Text document

Attachment: implicitptr.c
Description: Text document


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]