The minimum compiler version required for building LLVM has been raised to 4.8 for GCC and 2015 for Visual Studio.
The C API functions LLVMAddFunctionAttr, LLVMGetFunctionAttr, LLVMRemoveFunctionAttr, LLVMAddAttribute, LLVMRemoveAttribute, LLVMGetAttribute, LLVMAddInstrAttribute and LLVMRemoveInstrAttribute have been removed.
The C API enum LLVMAttribute has been deleted.
The definition and uses of LLVM_ATRIBUTE_UNUSED_RESULT in the LLVM source were replaced with LLVM_NODISCARD, which matches the C++17 [[nodiscard]] semantics rather than gcc’s __attribute__((warn_unused_result)).
The Timer related APIs now expect a Name and Description. When upgrading code the previously used names should become descriptions and a short name in the style of a programming language identifier should be added.
LLVM now handles invariant.group across different basic blocks, which makes it possible to devirtualize virtual calls inside loops.
The aggressive dead code elimination phase (“adce”) now removes branches which do not effect program behavior. Loops are retained by default since they may be infinite but these can also be removed with LLVM option -adce-remove-loops when the loop body otherwise has no live operations.
The llvm-cov tool can now export coverage data as json. Its html output mode has also improved.
The previous commit ended up with two different specifications for libtool
on Darwin. One was the OS-specific version of CMAKE_ARGS introduced in the
previous commit; the other was inside a conditional to detect Darwin introduced in the commit prior. The former seems cleaner so it has been left.
The LLVMContext gains a new runtime check (see LLVMContext::discardValueNames()) that can be set to discard Value names (other than GlobalValue). This is intended to be used in release builds by clients that are interested in saving CPU/memory as much as possible.
There is no longer a “global context” available in LLVM, except for the C API.
The autoconf build system has been removed in favor of CMake. LLVM 3.9 requires CMake 3.4.3 or later to build. For information about using CMake please see the documentation on Building LLVM with CMake. For information about the CMake language there is also a CMake Primer document available.
C API functions LLVMParseBitcode, LLVMParseBitcodeInContext, LLVMGetBitcodeModuleInContext and LLVMGetBitcodeModule having been removed. LLVMGetTargetMachineData has been removed (use LLVMGetDataLayout instead).
The C API function LLVMLinkModules has been removed.
The C API function LLVMAddTargetData has been removed.
The C API function LLVMGetDataLayout is deprecated in favor of LLVMGetDataLayoutStr.
The C API enum LLVMAttribute and associated API is deprecated in favor of the new LLVMAttributeRef API. The deprecated functions are LLVMAddFunctionAttr, LLVMAddTargetDependentFunctionAttr, LLVMRemoveFunctionAttr, LLVMGetFunctionAttr, LLVMAddAttribute, LLVMRemoveAttribute, LLVMGetAttribute, LLVMAddInstrAttribute, LLVMRemoveInstrAttribute and LLVMSetInstrParamAlignment.
TargetFrameLowering::eliminateCallFramePseudoInstr now returns an iterator to the next instruction instead of void. Targets that previously did MBB.erase(I); return; now probably want return MBB.erase(I);.
SelectionDAGISel::Select now returns void. Out-of-tree targets will need to be updated to replace the argument node and remove any dead nodes in cases where they currently return an SDNode * from this interface.
Added the MemorySSA analysis, which hopes to replace MemoryDependenceAnalysis. It should provide higher-quality results than MemDep, and be algorithmically faster than MemDep. Currently, GVNHoist (which is off by default) makes use of MemorySSA.
The minimum density for lowering switches with jump tables has been reduced from 40% to 10% for functions which are not marked optsize (that is, compiled with -Os).
* Drop CppBackend. It is removed.
Changelog:
* GCC ABI Tag
* LLVM IR: new intrinsics etc.
* Change LLVM IPO model
* Support ThinLTO
* Improve the ARM targets, ARMv8.2-A support etc.
* Improve the MIPS targets
* Improve the PowerPC target, default optim O3 to O2
* Improve the X86 target, SKylake AVX-512 etc.
* Improve the AMDGPU, better support for Mesa 12
jperkin Mon Mar 7 16:27:47 UTC 2016
Do not use "-z discard-unused" linker flags on SunOS, it is only supported
by the very latest Oracle Solaris release.
Packaged in pkgsrc-wip by myself and Kamil.
Remove stale pkgsrc/SunOS bread crumbs that were difficult to merge
following the build framework switch. Needs to be redone. (Sorry!)
Summary of significant changes in LLVM:
- switch build framework from autoconf to CMake
- llvm-ar now supports thin archives.
- llvm doesn t produce .data.rel.ro.local or .data.rel sections anymore.
- opional support for linking clang and the LLVM tools with a single
libLLVM shared library
pkgsrc note: we have this library in lang/libLLVM, but we don't currently
use it. We may do so in the future if/when the API matures.
- The optimization to move the prologue and epilogue of functions in colder
code path (shrink-wrapping) is now enabled by default
- new target-independent gcc-compatible emulated Thread Local Storage mode
- various target specific optimizations
Summary of significant changes in Clang:
- new compiler flags for tuning what DWARF information is included
- better strict alignment handling
- better support for __builtin_object_size
