12 This document contains the release notes for the LLVM Compiler Infrastructure,
13 release 3.8. Here we describe the status of LLVM, including major improvements
14 from the previous release, improvements in various subprojects of LLVM, and
15 some of the current users of the code. All LLVM releases may be downloaded
16 from the `LLVM releases web site <http://llvm.org/releases/>`_.
18 For more information about LLVM, including information about the latest
19 release, please check out the `main LLVM web site <http://llvm.org/>`_. If you
20 have questions or comments, the `LLVM Developer's Mailing List
21 <http://lists.llvm.org/mailman/listinfo/llvm-dev>`_ is a good place to send
24 Non-comprehensive list of changes in this release
25 =================================================
26 * With this release, the minimum Windows version required for running LLVM is
27 Windows 7. Earlier versions, including Windows Vista and XP are no longer
30 * With this release, the autoconf build system is deprecated. It will be removed
31 in the 3.9 release. Please migrate to using CMake. For more information see:
32 `Building LLVM with CMake <CMake.html>`_
34 * The C API function LLVMLinkModules is deprecated. It will be removed in the
35 3.9 release. Please migrate to LLVMLinkModules2. Unlike the old function the
38 * Doesn't take an unused parameter.
39 * Destroys the source instead of only damaging it.
40 * Does not record a message. Use the diagnostic handler instead.
42 * The C API functions LLVMParseBitcode, LLVMParseBitcodeInContext,
43 LLVMGetBitcodeModuleInContext and LLVMGetBitcodeModule have been deprecated.
44 They will be removed in 3.9. Please migrate to the versions with a 2 suffix.
45 Unlike the old ones the new ones do not record a diagnostic message. Use
46 the diagnostic handler instead.
48 * The deprecated C APIs LLVMGetBitcodeModuleProviderInContext and
49 LLVMGetBitcodeModuleProvider have been removed.
51 * The deprecated C APIs LLVMCreateExecutionEngine, LLVMCreateInterpreter,
52 LLVMCreateJITCompiler, LLVMAddModuleProvider and LLVMRemoveModuleProvider
55 * With this release, the C API headers have been reorganized to improve build
56 time. Type specific declarations have been moved to Type.h, and error
57 handling routines have been moved to ErrorHandling.h. Both are included in
58 Core.h so nothing should change for projects directly including the headers,
59 but transitive dependencies may be affected.
61 * llvm-ar now suports thin archives.
63 * llvm doesn't produce .data.rel.ro.local or .data.rel sections anymore.
65 * aliases to available_externally globals are now rejected by the verifier.
67 * the IR Linker has been split into IRMover that moves bits from one module to
68 another and Linker proper that decides what to link.
70 * Support for dematerializing has been dropped.
72 * RegisterScheduler::setDefault was removed. Targets that used to call into the
73 command line parser to set the DAGScheduler, and that don't have enough
74 control with setSchedulingPreference, should look into overriding the
75 SubTargetHook "getDAGScheduler()".
77 * ``ilist_iterator<T>`` no longer has implicit conversions to and from ``T*``,
78 since ``ilist_iterator<T>`` may be pointing at the sentinel (which is usually
79 not of type ``T`` at all). To convert from an iterator ``I`` to a pointer,
80 use ``&*I``; to convert from a pointer ``P`` to an iterator, use
81 ``P->getIterator()``. Alternatively, explicit conversions via
82 ``static_cast<T>(U)`` are still available.
84 * ``ilist_node<T>::getNextNode()`` and ``ilist_node<T>::getPrevNode()`` now
85 fail at compile time when the node cannot access its parent list.
86 Previously, when the sentinel was was an ``ilist_half_node<T>``, this API
87 could return the sentinal instead of ``nullptr``. Frustrated callers should
88 be updated to use ``iplist<T>::getNextNode(T*)`` instead. Alternatively, if
89 the node ``N`` is guaranteed not to be the last in the list, it is safe to
90 call ``&*++N->getIterator()`` directly.
93 For small 1-3 sentence descriptions, just add an entry at the end of
94 this list. If your description won't fit comfortably in one bullet
95 point (e.g. maybe you would like to give an example of the
96 functionality, or simply have a lot to talk about), see the `NOTE` below
97 for adding a new subsection.
102 If you would like to document a larger change, then you can add a
103 subsection about it right here. You can copy the following boilerplate
104 and un-indent it (the indentation causes it to be inside this comment).
109 Makes programs 10x faster by doing Special New Thing.
111 Changes to the ARM Backend
112 --------------------------
114 During this release ...
117 Changes to the MIPS Target
118 --------------------------
120 During this release the MIPS target has:
122 * Significantly extended support for the Integrated Assembler. See below for
124 * Added support for the ``P5600`` processor.
125 * Added support for the ``interrupt`` attribute for MIPS32R2 and later. This
126 attribute will generate a function which can be used as a interrupt handler
127 on bare metal MIPS targets using the static relocation model.
128 * Added support for the ``ERETNC`` instruction found in MIPS32R5 and later.
129 * Added support for OpenCL. See http://portablecl.org/.
131 * Address spaces 1 to 255 are now reserved for software use and conversions
132 between them are no-op casts.
134 * Removed the ``mips16`` value for the -mcpu option since it is an :abbr:`ASE
135 (Application Specific Extension)` and not a processor. If you were using this,
136 please specify another CPU and use ``-mips16`` to enable MIPS16.
137 * Removed ``copy_u.w`` from 32-bit MSA and ``copy_u.d`` from 64-bit MSA since
138 they have been removed from the MSA specification due to forward compatibility
139 issues. For example, 32-bit MSA code containing ``copy_u.w`` would behave
140 differently on a 64-bit processor supporting MSA. The corresponding intrinsics
141 are still available and may expand to ``copy_s.[wd]`` where this is
142 appropriate for forward compatibility purposes.
143 * Relaxed the ``-mnan`` option to allow ``-mnan=2008`` on MIPS32R2/MIPS64R2 for
144 compatibility with GCC.
145 * Made MIPS64R6 the default CPU for 64-bit Android triples.
147 The MIPS target has also fixed various bugs including the following notable
150 * Fixed reversed operands on ``mthi``/``mtlo`` in the DSP :abbr:`ASE
151 (Application Specific Extension)`.
152 * The code generator no longer uses ``jal`` for calls to absolute immediate
154 * Disabled fast instruction selection on MIPS32R6 and MIPS64R6 since this is not
156 * Corrected addend for ``R_MIPS_HI16`` and ``R_MIPS_PCHI16`` in MCJIT
157 * The code generator no longer crashes when handling subregisters of an 64-bit
158 FPU register with undefined value.
159 * The code generator no longer attempts to use ``$zero`` for operands that do
160 not permit ``$zero``.
161 * Corrected the opcode used for ``ll``/``sc`` when using MIPS32R6/MIPS64R6 and
162 the Integrated Assembler.
163 * Added support for atomic load and atomic store.
164 * Corrected debug info when dynamically re-aligning the stack.
168 We have made a large number of improvements to the integrated assembler for
169 MIPS. In this release, the integrated assembler isn't quite production-ready
170 since there are a few known issues related to bare-metal support, checking
171 immediates on instructions, and the N32/N64 ABI's. However, the current support
172 should be sufficient for many users of the O32 ABI, particularly those targeting
173 MIPS32 on Linux or bare-metal MIPS32.
175 If you would like to try the integrated assembler, please use
178 Changes to the PowerPC Target
179 -----------------------------
181 During this release ...
184 Changes to the X86 Target
185 -----------------------------
187 During this release ...
189 * TLS is enabled for Cygwin as emutls.
192 Changes to the OCaml bindings
193 -----------------------------
195 During this release ...
197 * The ocaml function link_modules has been replaced with link_modules' which
198 uses LLVMLinkModules2.
201 External Open Source Projects Using LLVM 3.8
202 ============================================
204 An exciting aspect of LLVM is that it is used as an enabling technology for
205 a lot of other language and tools projects. This section lists some of the
206 projects that have already been updated to work with LLVM 3.8.
208 LDC - the LLVM-based D compiler
209 -------------------------------
211 `D <http://dlang.org>`_ is a language with C-like syntax and static typing. It
212 pragmatically combines efficiency, control, and modeling power, with safety and
213 programmer productivity. D supports powerful concepts like Compile-Time Function
214 Execution (CTFE) and Template Meta-Programming, provides an innovative approach
215 to concurrency and offers many classical paradigms.
217 `LDC <http://wiki.dlang.org/LDC>`_ uses the frontend from the reference compiler
218 combined with LLVM as backend to produce efficient native code. LDC targets
219 x86/x86_64 systems like Linux, OS X and Windows and also PowerPC (32/64 bit)
220 and ARM. Ports to other architectures like AArch64 and MIPS64 are underway.
223 Additional Information
224 ======================
226 A wide variety of additional information is available on the `LLVM web page
227 <http://llvm.org/>`_, in particular in the `documentation
228 <http://llvm.org/docs/>`_ section. The web page also contains versions of the
229 API documentation which is up-to-date with the Subversion version of the source
230 code. You can access versions of these documents specific to this release by
231 going into the ``llvm/docs/`` directory in the LLVM tree.
233 If you have any questions or comments about LLVM, please feel free to contact
234 us via the `mailing lists <http://llvm.org/docs/#maillist>`_.