Add Bitmap::view() and forward most of the calls to BitmapView since
the code was identical.
Bitmap is now primarily concerned with its dynamically allocated
backing store and BitmapView deals with the rest.
This is a little bit messy, but basically if an ELF object is non-PIE,
we have to account for the executable mapping being at a hard-coded
offset and subtract that when doing symbolication.
There's probably a nicer way to solve this, I just hacked this together
so we can see "cc1plus" and friends in profiles. :^)
In multi-process profiles, the same ELF objects tend to occur many
times (everyone has libc.so for example) so we will quickly run out
of VM if we map each object once per process that uses it.
Fix this by adding a "mapped object cache" that maps the path of
an ELF object to a cached memory mapping and wrapping ELF::Image.
The perfcore file format was previously limited to a single process
since the pid/executable/regions data was top-level in the JSON.
This patch moves the process-specific data into a top-level array
named "processes" and we now add entries for each process that has
been sampled during the profile run.
This makes it possible to see samples from multiple threads when
viewing a perfcore file with Profiler. This is extremely cool! :^)
You can now view the individual samples in a profile one by one with
the new "Samples" view. The "old" main view moves into a "Call Tree"
tab (but it remains the default view.)
When you select a sample in the samples view, we show you the full
symbolicated backtrace in a separate view on the right hand side. :^)
This way you don't have to look at all the library names if you don't
want to. Since we're pretty good about namespacing our things, the
library names are slightly redundant information.
(...and ASSERT_NOT_REACHED => VERIFY_NOT_REACHED)
Since all of these checks are done in release builds as well,
let's rename them to VERIFY to prevent confusion, as everyone is
used to assertions being compiled out in release.
We can introduce a new ASSERT macro that is specifically for debug
checks, but I'm doing this wholesale conversion first since we've
accumulated thousands of these already, and it's not immediately
obvious which ones are suitable for ASSERT.
