1 / 10

Advanced Compiler Design

Advanced Compiler Design. An Introduction to the Javali Compiler Framework. Zoltán Majó. Javali. Simple object-oriented programming language Your tasks in this lecture are: Implement an SSA-based IR Implement some compiler optimizations Come up with your own project

tomai
Télécharger la présentation

Advanced Compiler Design

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Advanced Compiler Design An Introduction to the Javali Compiler Framework Zoltán Majó

  2. Javali • Simple object-oriented programming language • Your tasks in this lecture are: • Implement an SSA-based IR • Implement some compiler optimizations • Come up with your own project • ... and you have to do all this for Javali

  3. Javali • You may build your own Javali compiler • We provide a framework that already implements • Parsing • IR • Code generation • Semantic checking • You can extend the framework

  4. Outline • Building the Control Flow Graph (CFG) • Debugging & Testing

  5. Example: counting # of zero/non-zero elements Program code class Main { void main() { int count, i, zeros, notZeros; count = read(); i = 0; zeros = 0; notZeros = 0; while (i < count) { input = read(); if (input == 0) { zeros++; } else { notZeros++; } i++; } write(zeros); write(notZeros); } }

  6. Constructing the Control Flow Graph Program code Control Flow Graph class Main { void main() { int count, i, zeros, notZeros; count = read(); i = 0; zeros = 0; notZeros = 0; while (i < count) { input = read(); if (input == 0) { zeros++; } else { notZeros++; } i++; } write(zeros); write(notZeros); } } BB1 count = read(); i = 0; zeros = 0; notZeros = 0; false BB2 COND(i < count) true BB3 input = read(); COND(input == 0) true false BB4 zeros++; BB5 notZeros++; BB6 i++; BB7 write(zeros); write(notZeros);

  7. Implementing CFG Construction Program code Abstract Syntax Tree class Main { void main() { int count, i, zeros, notZeros; count = read(); i = 0; zeros = 0; notZeros = 0; while (i < count) { input = read(); if (input == 0) { zeros++; } else { notZeros++; } i++; } write(zeros); write(notZeros); } } Assign Var::count BuiltInRead WhileLoop BinaryOp::< Seq Var::i Var::count Assign ... Var::input BuiltInRead

  8. Implementing CFG Construction • Simple idea: for each method of the program { walk through the method’s list of AST nodes add each AST node to the current basic block } • More action required: IfElse and WhileLoop AST nodes • Create new basic blocks if necessary • Connect new basic blocks to existing ones so that connections reflect the method’s control flow • Not allowed in the CFG: IfElse and WhileLoop AST nodes • Use Visitor pattern to traverse AST: extend AstVisitor • Add all this functionality to CFGBuilder.build()

  9. Debugging • In debug mode compiler dumps CFG into a *cfg.dot file • Use dotty from the Graphviz package to visualize CFG Testing • Example programs included in the javali_tests directory • Get reference CFG generated by our server:run TestSampleProgramsas JUnit test

  10. Thanks! Questions? Get fragment from: https://svn.inf.ethz.ch/svn/trg/cd_students/2012ss/teams/<your_team>/CD2_A0/

More Related