Working with the new AnalysisManager
Modern compiler optimizations can be complex. They usually require lots of information from the target program in order to make correct decisions and optimal transformations. For example, in the Writing an LLVM Pass for the new PassManager section, LLVM used the noalias attribute to calculate memory aliasing information, which might eventually be used to remove redundant memory loads.
Some of this information – called analysis, in LLVM – is expensive to evaluate. In addition, a single analysis might also depend on other analyses. Therefore, LLVM creates an AnalysisManager component to handle all tasks related to program analysis in LLVM. In this section, we are going to show you how to use AnalysisManager in your own Passes for the sake of writing more powerful and sophisticated program transformations or analyses. We will also use a sample project, HaltAnalyzer, to drive our tutorial here. The next section will provide you with...
