旧式的LLVM PASS 是通过Legacy PassManager 来管理的。 但在Legacy Pass Manager的使用过程中,例如:CGSCC 分析中,call graph 数据结构不能作为索引来缓存分析结果,所以我们为了增量更新需要将整个 graph 放在内存中作为索引,导致了过多的冗余操作,且还需要手动声明依赖,又有基于虚函数的多继承(继承FunctionPass)等待缺...
- 若一个Pass为一个分析Pass,如是一个支配数Pass,此时第四个参数为true 若希望将写好的Pass作为现有流水线的一步,需要提供一些扩展指针,如PassManagerBuilder::EP_EarlyAsPossible,来在所有优化之前使用编写的Pass,或者使用PassManagerBuilder::EP_FullLinkTimeOptimizationLast,来在链接优化后面运行。 对应的使用...
g_llvm_module = std::make_unique<Module>("my cool jit", g_llvm_context); // Create a new pass manager attached to it. g_fpm = std::make_unique<legacy::FunctionPassManager>(g_llvm_module.get()); // Do simple "peephole" optimizations and bit-twiddling optzns. g_fpm->add(createI...
-DCMAKE_BUILD_TYPE=type Controls optimization level and debug information of the build. For more detailed information see CMAKE_BUILD_TYPE (https://llvm.org/docs/CMake.html)。Type的类型有:Release,Debug,RelWithDebInfo,MinSizeRel。Debug一般是为了开发,普通使用Release就行了。如果是Debug,请准备足够...
3.Multiplication and Division Optimization 大家应该多少听过,因为电脑在储存整数时是采用二进制,所以乘2 跟除2 可以用左移跟右移一格来取代,而且shift对CPU 来讲很简单,所以做起来会比乘法快很多 看下图,因为左边例子中的8 是2³,而16 是2⁴,所以 x * 8 会被”优化”成x << 3,而 x / 16 则是...
get_pass_manager().run(&mut function); // clear local variables context.named_values.clear(); Ok((function.to_ref(), self.prototype.name.as_str() == "")) } } We can try to run our example again and see if optimization helps: > def test(x) (1+2+x)*(x+(1+2)); define ...
Youtube上一个教程:The Clang AST - a Tutorial - YouTube CMU关于llvm的教案 http://www.cs.cmu.edu/afs/cs.cmu.edu/academic/class/15745-s14/public/lectures/ 静态分析前会对源代码分词成 Token,这个过程称为词法分析(Lexical Analysis),在 TokensKind.def 里有Clang 定义的所有 Token。Token 可以分为以...
PB.registerPipelineStartEPCallback(myCallback);voidmyCallback(llvm::ModulePassManager &PM, llvm::PassBuilder::OptimizationLevel Level){PM.addPass(TestPass());}classTestPass{public:staticStringRefname(){errs() <<"name invoked\n";return"TestPass";...
Code Issues Pull requests Project moved to: https://github.com/llvm/llvm-project optimization virtual-machine llvm code-generation intermediate-representation Updated Sep 2, 2020 LLVM scala-native / scala-native Star 4.6k Code Issues Pull requests Discussions Your favorite language gets closer...
A powerful pass-management system that automatically sequences passes (including analysis, transformation, and code-generation passes) based on their dependences, and pipelines them for efficiency. A wide range of global scalar optimizations. A link-time interprocedural optimization framework with a rich...