2019-07-18 11:51:05 +00:00
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=========================
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2020-01-15 10:02:56 +01:00
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LLVM 11.0.0 Release Notes
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2019-07-18 11:51:05 +00:00
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=========================
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2012-12-09 23:14:26 +00:00
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.. contents::
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:local:
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2013-01-20 03:29:50 +00:00
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.. warning::
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2020-01-15 10:02:56 +01:00
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These are in-progress notes for the upcoming LLVM 11 release.
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2017-02-09 23:03:34 +00:00
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Release notes for previous releases can be found on
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2018-09-10 08:50:31 +00:00
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`the Download Page <https://releases.llvm.org/download.html>`_.
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2012-12-09 23:14:26 +00:00
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Introduction
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============
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This document contains the release notes for the LLVM Compiler Infrastructure,
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release 11.0.0. Here we describe the status of LLVM, including major improvements
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from the previous release, improvements in various subprojects of LLVM, and
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some of the current users of the code. All LLVM releases may be downloaded
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from the `LLVM releases web site <https://llvm.org/releases/>`_.
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2012-12-09 23:14:26 +00:00
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For more information about LLVM, including information about the latest
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2018-09-10 08:50:31 +00:00
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release, please check out the `main LLVM web site <https://llvm.org/>`_. If you
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2012-12-09 23:14:26 +00:00
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have questions or comments, the `LLVM Developer's Mailing List
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2018-09-10 08:50:31 +00:00
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<https://lists.llvm.org/mailman/listinfo/llvm-dev>`_ is a good place to send
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2012-12-09 23:14:26 +00:00
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them.
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Note that if you are reading this file from a Git checkout or the main
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LLVM web page, this document applies to the *next* release, not the current
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one. To see the release notes for a specific release, please see the `releases
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2018-09-10 08:50:31 +00:00
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page <https://llvm.org/releases/>`_.
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2012-12-09 23:14:26 +00:00
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2013-01-20 03:29:50 +00:00
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Non-comprehensive list of changes in this release
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=================================================
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.. NOTE
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For small 1-3 sentence descriptions, just add an entry at the end of
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this list. If your description won't fit comfortably in one bullet
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point (e.g. maybe you would like to give an example of the
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functionality, or simply have a lot to talk about), see the `NOTE` below
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for adding a new subsection.
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2020-01-15 10:02:56 +01:00
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* ...
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2020-05-23 13:51:43 +02:00
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2019-11-08 10:05:37 -08:00
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2013-01-20 03:29:50 +00:00
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.. NOTE
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If you would like to document a larger change, then you can add a
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subsection about it right here. You can copy the following boilerplate
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and un-indent it (the indentation causes it to be inside this comment).
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2013-01-20 03:29:50 +00:00
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Special New Feature
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-------------------
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2013-01-20 03:29:50 +00:00
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Makes programs 10x faster by doing Special New Thing.
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2019-12-24 18:12:15 -08:00
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2016-03-29 06:55:56 +00:00
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Changes to the LLVM IR
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----------------------
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2020-02-21 16:15:09 +00:00
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* The callsite attribute `vector-function-abi-variant
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<https://llvm.org/docs/LangRef.html#call-site-attributes>`_ has been
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added to describe the mapping between scalar functions and vector
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functions, to enable vectorization of call sites. The information
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provided by the attribute is interfaced via the API provided by the
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``VFDatabase`` class.
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2019-08-03 14:28:34 +00:00
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2020-05-16 17:55:18 -07:00
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* `dereferenceable` attributes and metadata on pointers no longer imply
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anything about the alignment of the pointer in question. Previously, some
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optimizations would make assumptions based on the type of the pointer. This
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behavior was undocumented. To preserve optimizations, frontends may need to
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be updated to generate appropriate `align` attributes and metadata.
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2020-05-27 14:01:35 +05:30
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* The DIModule metadata is extended to contain file and line number
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information. This information is used to represent Fortran modules debug
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info at IR level.
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2019-07-09 10:10:48 +00:00
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Changes to building LLVM
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------------------------
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2014-03-18 10:16:15 +00:00
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Changes to the ARM Backend
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--------------------------
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2020-01-15 10:02:56 +01:00
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During this release ...
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2014-08-22 21:57:38 +00:00
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2020-03-24 11:37:51 +00:00
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* Implemented C-language intrinsics for the full Arm v8.1-M MVE instruction
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set. ``<arm_mve.h>`` now supports the complete API defined in the Arm C
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Language Extensions.
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2014-03-18 10:16:15 +00:00
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2020-04-22 16:34:19 +01:00
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* Added support for assembly for the optional Custom Datapath Extension (CDE)
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for Arm M-profile targets.
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2020-04-22 18:25:22 +01:00
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* Implemented C-language intrinsics ``<arm_cde.h>`` for the CDE instruction set.
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2020-04-22 16:34:19 +01:00
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[Clang][A32/T32][Linux] -O1 implies -fomit-frame-pointer
Summary:
An upgrade of LLVM for CrOS [0] containing [1] triggered a bunch of
errors related to writing to reserved registers for a Linux kernel's
arm64 compat vdso (which is a aarch32 image).
After a discussion on LKML [2], it was determined that
-f{no-}omit-frame-pointer was not being specified. Comparing GCC and
Clang [3], it becomes apparent that GCC defaults to omitting the frame
pointer implicitly when optimizations are enabled, and Clang does not.
ie. setting -O1 (or above) implies -fomit-frame-pointer. Clang was
defaulting to -fno-omit-frame-pointer implicitly unless -fomit-frame-pointer
was set explicitly.
Why this becomes a problem is that the Linux kernel's arm64 compat vdso
contains code that uses r7. r7 is used sometimes for the frame pointer
(for example, when targeting thumb (-mthumb)). See useR7AsFramePointer()
in llvm/llvm-project/llvm/lib/Target/ARM/ARMSubtarget.h. This is mostly
for legacy/compatibility reasons, and the 2019 Q4 revision of the ARM
AAPCS looks to standardize r11 as the frame pointer for aarch32, though
this is not yet implemented in LLVM.
Users that are reliant on the implicit value if unspecified when
optimizations are enabled should explicitly choose -fomit-frame-pointer
(new behavior) or -fno-omit-frame-pointer (old behavior).
[0] https://bugs.chromium.org/p/chromium/issues/detail?id=1084372
[1] https://reviews.llvm.org/D76848
[2] https://lore.kernel.org/lkml/20200526173117.155339-1-ndesaulniers@google.com/
[3] https://godbolt.org/z/0oY39t
Reviewers: kristof.beyls, psmith, danalbert, srhines, MaskRay, ostannard, efriedma
Reviewed By: psmith, danalbert, srhines, MaskRay, efriedma
Subscribers: efriedma, olista01, MaskRay, vhscampos, cfe-commits, llvm-commits, manojgupta, llozano, glider, hctim, eugenis, pcc, peter.smith, srhines
Tags: #clang, #llvm
Differential Revision: https://reviews.llvm.org/D80828
2020-06-02 15:54:09 -07:00
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* Clang now defaults to ``-fomit-frame-pointer`` when targeting non-Android
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Linux for arm and thumb when optimizations are enabled. Users that were
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previously not specifying a value and relying on the implicit compiler
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default may wish to specify ``-fno-omit-frame-pointer`` to get the old
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behavior. This improves compatibility with GCC.
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2014-07-23 12:59:26 +00:00
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Changes to the MIPS Target
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--------------------------
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During this release ...
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2015-01-11 10:34:52 +00:00
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2014-07-23 12:59:26 +00:00
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2014-07-31 14:38:17 +00:00
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Changes to the PowerPC Target
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2014-07-31 15:20:30 +00:00
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-----------------------------
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2014-07-31 14:38:17 +00:00
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2020-01-15 10:02:56 +01:00
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During this release ...
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2014-07-31 14:38:17 +00:00
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2015-12-21 02:37:23 +00:00
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Changes to the X86 Target
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2016-03-29 06:55:56 +00:00
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-------------------------
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2015-12-21 02:37:23 +00:00
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2020-01-15 10:02:56 +01:00
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During this release ...
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2019-08-28 17:18:56 +00:00
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2019-09-09 16:59:34 +02:00
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* Functions with the probe-stack attribute set to "inline-asm" are now protected
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against stack clash without the need of a third-party probing function and
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with limited impact on performance.
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2020-04-15 12:03:39 -07:00
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* -x86-enable-old-knl-abi command line switch has been removed. v32i16/v64i8
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vectors are always passed in ZMM register when avx512f is enabled and avx512bw
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is disabled.
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* Vectors larger than 512 bits with i16 or i8 elements will be passed in
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multiple ZMM registers when avx512f is enabled. Previously this required
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avx512bw otherwise they would split into multiple YMM registers. This means
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vXi16/vXi8 vectors are consistently treated the same as
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vXi32/vXi64/vXf64/vXf32 vectors of the same total width.
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2019-09-09 16:59:34 +02:00
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2016-01-26 04:29:15 +00:00
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Changes to the AMDGPU Target
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-----------------------------
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2019-10-31 23:32:31 -07:00
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* The backend default denormal handling mode has been switched to on
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for all targets for all compute function types. Frontends wishing to
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retain the old behavior should explicitly request f32 denormal
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flushing.
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2016-11-17 22:26:09 +00:00
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Changes to the AVR Target
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-----------------------------
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2020-03-16 20:07:59 +13:00
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* Moved from an experimental backend to an official backend. AVR support is now
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included by default in all LLVM builds and releases and is available under
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the "avr-unknown-unknown" target triple.
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2016-11-17 22:26:09 +00:00
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2019-01-14 18:20:30 +00:00
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Changes to the WebAssembly Target
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---------------------------------
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2020-06-09 17:34:55 -07:00
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* Programs which don't have a "main" function, called "reactors" are now
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properly supported, with a new `-mexec-model=reactor` flag. Programs which
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previously used `-Wl,--no-entry` to avoid having a main function should
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switch to this new flag, so that static initialization is properly
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performed.
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* `__attribute__((visibility("protected")))` now evokes a warning, as
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WebAssembly does not support "protected" visibility.
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2019-01-14 18:20:30 +00:00
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2015-01-13 09:48:02 +00:00
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Changes to the OCaml bindings
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-----------------------------
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2016-02-17 19:35:47 +00:00
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2017-06-30 01:17:45 +00:00
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Changes to the C API
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--------------------
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2019-12-03 09:29:54 +05:30
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Changes to the Go bindings
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--------------------------
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2017-06-30 01:17:45 +00:00
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2017-06-30 07:09:08 +00:00
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Set ADDE/ADDC/SUBE/SUBC to expand by default
Summary:
They've been deprecated in favor of UADDO/ADDCARRY or USUBO/SUBCARRY for a while.
Target that uses these opcodes are changed in order to ensure their behavior doesn't change.
Reviewers: efriedma, craig.topper, dblaikie, bkramer
Subscribers: jholewinski, arsenm, jyknight, sdardis, nemanjai, nhaehnle, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, jordy.potman.lists, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, llvm-commits
Differential Revision: https://reviews.llvm.org/D47422
llvm-svn: 333748
2018-06-01 13:21:33 +00:00
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Changes to the DAG infrastructure
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---------------------------------
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2018-06-04 18:36:22 +00:00
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2020-04-07 12:05:22 +02:00
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Changes to the Debug Info
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---------------------------------
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* LLVM now supports the debug entry values (DW_OP_entry_value) production for
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the x86, ARM, and AArch64 targets by default. Other targets can use
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the utility by using the experimental option ("-debug-entry-values").
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This is a debug info feature that allows debuggers to recover the value of
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optimized-out parameters by going up a stack frame and interpreting the values
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passed to the callee. The feature improves the debugging user experience when
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debugging optimized code.
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2020-04-10 10:33:33 +02:00
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Changes to the LLVM tools
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---------------------------------
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* Added an option (--show-section-sizes) to llvm-dwarfdump to show the sizes
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of all debug sections within a file.
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2019-07-05 17:58:30 +00:00
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Changes to LLDB
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===============
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2020-01-15 10:02:56 +01:00
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External Open Source Projects Using LLVM 11
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===========================================
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2015-01-13 09:48:02 +00:00
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2016-07-18 18:02:23 +00:00
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* A project...
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2013-11-14 05:57:40 +00:00
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2012-12-09 23:14:26 +00:00
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Additional Information
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======================
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A wide variety of additional information is available on the `LLVM web page
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2018-09-10 08:50:31 +00:00
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<https://llvm.org/>`_, in particular in the `documentation
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<https://llvm.org/docs/>`_ section. The web page also contains versions of the
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API documentation which is up-to-date with the Git version of the source
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code. You can access versions of these documents specific to this release by
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going into the ``llvm/docs/`` directory in the LLVM tree.
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If you have any questions or comments about LLVM, please feel free to contact
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2018-09-10 08:50:31 +00:00
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us via the `mailing lists <https://llvm.org/docs/#mailing-lists>`_.
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