[msan] Chained origins re-design.

Description

[msan] Chained origins re-design.

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.

Details

Committed
eugenisMay 21 2014, 2:02 AM
Parents
rL209283: [lsan] disable lsan if wordsize is not 64
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