This relates to https://reviews.llvm.org/D95835.
In DFSan origin tracking we use StackDepot to record
stack traces and origin traces (like MSan origin tracking).
For at least two reasons, we wanted to control StackDepot's memory cost
1) We may use DFSan origin tracking to monitor programs that run for
many days. This may eventually use too much memory for StackDepot.
2) DFSan supports flush shadow memory to reduce overhead. After flush,
all existing IDs in StackDepot are not valid because no one will
refer to them.
Split out of D87120 (memory profiler). Added unit testing of the new
printing facility.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D87792
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Chained origins make plain memory stores async-signal-unsafe.
We already disable it inside signal handlers.
This change grabs all origin-related locks before fork() and releases
them after fork() to avoid a deadlock in the child process.
llvm-svn: 217140
Generalize StackDepot and create a new specialized instance of it to
efficiently (i.e. without duplicating stack trace data) store the
origin history tree.
This reduces memory usage for chained origins roughly by an order of
magnitude.
Most importantly, this new design allows us to put two limits on
stored history data (exposed in MSAN_OPTIONS) that help avoid
exponential growth in used memory on certain workloads.
See comments in lib/msan/msan_origin.h for more details.
llvm-svn: 209284
Jianzhou Zhao