tree dcc42652da95a34aaa053a3cab985989fa2148cf
parent 9ec260fd8edc733477209c9b35ccfd9ec7e2076c
author Martin Kustermann <kustermann@google.com> 1544803384 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> 1544803384 +0000

[VM] Bare instructions - Part 4: Add --use-bare-instructions flag to AOT compiler & runtime

This is the final CL which adds a new --use-bare-instructions flag to
the VM.

If this flag is set during AOT compilation, we will:

  * Build one global object pool (abbr: GOP) which all code objects
    share. This gop will be stored in the object store.  The PP register
    is populated in the enter dart stub and it is restored when
    returning from native calls.

  * Gets rid of the CODE_REG/PP slots from the dart frames. Instead the
    compiled code uses the global object pool, which is always in PP.

  * Starts emitting pc-relative calls for calls between two dart
    functions or when invoking a stub.
    Limitation: We only emit pc-relative calls between two code objects
    in the same isolate (this is because the image writer is writing
    instruction objects for vm-isolate/main-isolate seperately)

  * We do compile-time relocation of those static calls after the
    precompiler has finished its work, but before writing the snapshot.
    This patches all the instruction objects with pc-relative calls to
    have the right .text distance.

  * We emit a sorted list of code objects in ObjectStore::reverse_code_table,
    which will be used by the AOT runtime to go back from PC to Code
    objects (where all metadata, e.g. stack maps, catch entry moves, pc
    descriptors are available).

Issue https://github.com/dart-lang/sdk/issues/33274

Change-Id: I6c5dd2b1571e3a889b27e804a24c2986c71e03b6
Reviewed-on: https://dart-review.googlesource.com/c/85769
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Vyacheslav Egorov <vegorov@google.com>