发布于 2016-09-02 23:22:01 | 187 次阅读 | 评论: 0 | 来源: 网友投递
LLVM 编译器架构
LLVM是构架编译器(compiler)的框架系统，以C++编写而成，用于优化以任意程序语言编写的程序的编译时间(compile-time)、链接时间(link-time)、运行时间(run-time)以及空闲时间(idle-time)，对开发者保持开放，并兼容已有脚本。
LLVM 3.9 发布了，
该版本改进记录如下：
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).
了解更多改进信息，查看完整发布说明。
使用文档：http://llvm.org/releases/3.9.0/docs/index.html
下载地址：http://llvm.org/releases/download.html#3.9.0