The OCaml bindings currently return pointers to LLVM objects as-is to
OCaml. These "naked pointers" end up appearing as values of local
variables in OCaml code, stored as part of other OCaml values,
etc. The safety of this design relies on the OCaml runtime system's
ability to distinguish these pointers from pointers to memory on the
OCaml garbage collected heap. In particular, when the OCaml GC
encounters a pointer to memory known to not be part of the OCaml heap,
it does not follow it.
In OCaml 4.02 an optimized "no naked pointers" mode was introduced
where the runtime system does not perform such checks and requires
that no such naked pointers be passed to OCaml code, instead one of
several encodings needs to be used. In OCaml 5, the no naked pointers
mode is now the only mode. This diff uses one of the potential
encodings to eliminate naked pointers, making the LLVM OCaml bindings
compatible with the "no naked pointers" mode of OCaml >= 4.02 and 5.
The encoding implemented in this diff relies on LLVM objects to be at
least 2-byte aligned, meaning that the lsb of pointers will
necessarily be clear. The encoding sets the lsb when passing LLVM
pointers to OCaml, and clears it on the return path. Setting the lsb
causes the OCaml runtime system to interpret the resulting value as a
tagged integer, which does not participate in garbage collection.
In some cases, particularly functions that receive an OCaml array of
LLVM pointers, this encoding requires allocation of a temporary array,
but otherwise this diff aims to preserve the existing performance
characteristics of the OCaml bindings.
Reviewed By: jberdine
Differential Revision: https://reviews.llvm.org/D136400
The removal of CAMLprim left the code in need of an application of
clang-format. There are various other changes made by clang-format
which it seems ought to be rolled together into this diff.
Differential Revision: https://reviews.llvm.org/D99477
The CAMLprim macro has not been needed since OCaml 3.11, and is
defined to the empty string. This diff removes all instances of it.
Differential Revision: https://reviews.llvm.org/D99476
Use exact component name in add_ocaml_library.
Make expand_topologically compatible with new architecture.
Fix quoting in is_llvm_target_library.
Fix LLVMipo component name.
Write release note.
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
Summary: Just copypasta resulting in the wrong file name in the header.
Reviewers: whitequark
Reviewed By: whitequark
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52215
llvm-svn: 342437
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html
"I felt a great disturbance in the [build system], as if millions of [makefiles] suddenly cried out in terror and were suddenly silenced. I fear something [amazing] has happened."
- Obi Wan Kenobi
Reviewers: chandlerc, grosbach, bob.wilson, tstellarAMD, echristo, whitequark
Subscribers: chfast, simoncook, emaste, jholewinski, tberghammer, jfb, danalbert, srhines, arsenm, dschuff, jyknight, dsanders, joker.eph, llvm-commits
Differential Revision: http://reviews.llvm.org/D16471
llvm-svn: 258861
