The RecordCoverage instruction has an A/E encoding. The A argument
is the type of coverage being recorded, whereas the E argument is
the logical index into the coverage array for updating whether that
source position has been hit.
Also adds new metadata to the bytecode component for the coverage
arrays associated with bytecode containing RecordCoverage instructions
and a new runtime entry for lazily allocate the coverage array for
an interpreted function when needed.
The type of coverage is encoded in the RecordCoverage instruction,
despite being redundant with the information in the coverage array, so that checking whether that type of coverage is currently enabled at
runtime doesn't require either accessing the coverage array (which may
be lazily allocated), forcing allocation of the coverage array just to
discover that type of coverage is currently disabled, or reading the
serialized bytecode component to avoid that forced allocation.
------
Other changes:
Source reporting now treats unexecuted interpreted functions when
not forcing compilation as if they were uncompiled native functions,
so that the source report from running the same code gives the same
result whether using the interpreter or the native compiler.
Bytecode closures are no longer skipped in source reports. Previously
any closure without a context scope was skipped, but bytecode closures
don't have those.
TEST=vm/cc/SourceReport_Coverage
Cq-Include-Trybots: luci.dart.try:vm-dyn-linux-debug-x64-try,vm-aot-dyn-linux-debug-x64-try,vm-aot-dyn-linux-product-x64-try
Change-Id: I7557e5dd4c98331c7ca2f5c867dd5f6d03e9d756
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/501520
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Tess Strickland
52cfd29cbb