Taking advantage of the new closure representation, this PR simplifies the compaction algorithm (3 passes instead of 4) and remove the use of the page table in no-naked-pointers mode.
The instrumentation code in the instrumented runtime was replaced
with new APIs to gather runtime statistics and output them in a new format
(Common Trace Format).
This commit also exposes new functions in the Gc module to pause or resume
instrumentation during a program execution (Gc.eventlog_pause and
Gc.eventlog_resume).
The user can register several callbacks, which are called for various
events during the block's lifetime. We need to maintain a data
structure for tracked blocks in the runtime. When using threads,
callbacks can be called concurrently in a reentrant way, so the
functions manipulating this data structure need to be reentrant.
Damien Doligez
Sadiq Jaffer
Leo White
Enguerrand Decorne
Jacques-Henri Jourdan
KC Sivaramakrishnan
Sébastien Hinderer