The load bias is documented to be the difference between
the preferred and actual load address for a module, but
is declared as an unsigned number, and math using it relies
on it being a pointer-precisioned two's complement number
that might cause over- or under-flow.
ElfImageReader and DebugRendezvous both provide ways to get
the load bias for a module and are corroborated in tests.
However, the load bias computed by DebugRendezvous does
not have access to the preferred address, so there is not
enough information to determine the signedness to use with
a VMOffset.
This patch compares the load biases modulo the numeric range
for a pointer to ignore the signedness of the value.
Also update the test module to trigger a negative load bias.
Bug: chromium:1147922
Change-Id: I55bc49195cfb2def06777e26388380fb9bc0f710
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/2569886
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Mark Mentovai <mark@chromium.org>
A step towards making these files usable by non-Linux systems.
Bug: crashpad:196
Change-Id: I71323b29e46208b3992055722e4622d79409c44c
Reviewed-on: https://chromium-review.googlesource.com/685406
Commit-Queue: Dave Bort <dbort@google.com>
Reviewed-by: Mark Mentovai <mark@chromium.org>
Dynamic linkers use `struct r_debug` and `struct link_map` (defined in
`<link.h>`) to communicate lists of loaded modules to debuggers.
Bug: crashpad:30
Change-Id: Id903a1c199288dd85c34e38710cdb4c6b5fedb5b
Reviewed-on: https://chromium-review.googlesource.com/534853
Reviewed-by: Mark Mentovai <mark@chromium.org>
