Mercurial > hg > truffle

annotate doc/design/graal_compiler.tex @ 2561:765dd54244a6

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Updated doc. Added Texclipse project.
author Thomas Wuerthinger <thomas@wuerthinger.net>
date Fri, 29 Apr 2011 16:51:33 +0200
parents 8c6e31c62fba
children 0023bd42eefe
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
rev   line source
2517
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
1 \documentclass[twocolumn]{svjour3}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
2 \usepackage[pdftex]{graphicx}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
3 \usepackage{environ}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
4 \usepackage{amsmath}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
5 \usepackage{amsfonts}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
6 \usepackage[english]{babel}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
7 \usepackage[utf8]{inputenc}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
8 \usepackage{lmodern}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
9 \usepackage[T1]{fontenc}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
10 \usepackage{color}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
11
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
12 \input{graphdrawing}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
13
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
14 \renewcommand*\descriptionlabel[1]{\hspace\labelsep\normalfont\bf #1}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
15
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
16 \newcommand{\Sa}{{\Large$^*$}}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
17 \newcommand{\Sb}{{\Large$^\dag$}}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
18 \newcommand{\Sc}{{\Large$^\S$}}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
19
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
20 \smartqed % flush right qed marks, e.g. at end of proof
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
21
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
22 \journalname{Graal Compiler Design}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
23 \def\makeheadbox{{%
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
24 \hbox to0pt{\vbox{\baselineskip=10dd\hrule\hbox
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
25 to\hsize{\vrule\kern3pt\vbox{\kern3pt
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
26 \hbox{\bfseries The Graal Compiler - Design and Strategy}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
27 \kern3pt}\hfil\kern3pt\vrule}\hrule}%
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
28 \hss}}}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
29
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
30 \begin{document}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
31
2561
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
32 \author{Thomas W\"{u}rthinger \Sa, Lukas Stadler \Sc, Gilles Duboscq \Sa}
2517
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
33 \institute{\Sa Oracle, \Sc Johannes Kepler University, Linz}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
34
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
35 \date{Created: \today}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
36
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
37 \title{The Graal Compiler}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
38 \subtitle{Design and Strategy \\ \textcolor{red}{work in progress}}
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
39
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
40 \maketitle
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
41
2561
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
42 \abstract{
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
43 The Graal compiler aims at improving C1X, the Java port of the HotSpot client compiler, both in terms of modularity and peak performance.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
44 The compiler should work with the Maxine VM and the HotSpot VM.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
45 This document contains information about the proposed design and strategy for developing the Graal compiler.}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
46
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
47 \section{Context}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
48
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
49 In 2009, the Maxine team started with creating C1X, a Java port of the HotSpot client compiler, and integrate it into the Maxine VM.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
50 Part of this effort, was the development of a clear and clean compiler-runtime interface that allows the separation of the compiler and the VM that enables the use of one compiler for multiple VMs.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
51 In June 2010, we started integrating C1X into the HotSpot VM and we called the resulting system Graal~VM.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
52 Currently, the Graal~VM is fully functional and runs benchmarks (SciMark, DaCapo) at a similar speed to the HotSpot client compiler.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
53
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
54 \section{Goals}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
55 The Graal compiler effort aims at rewriting the high-level intermediate representation of C1X with two main goals:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
56 \begin{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
57 \item[Modularity:] A modular design of the compiler should simplify the implementation of new languages, new back-ends, and new optimizations.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
58 \item[Peak Performance:] A more powerful intermediate representation should enable the implementation of heavy-weight optimizations that impact the peak performance of the resulting machine code.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
59 \end{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
60
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
61 \section{Design}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
62 For the implementation of the Graal compiler, we rely on the following design decisions:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
63 \begin{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
64 \item[Graph Representation:]
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
65 The compiler's intermediate representation is modelled as a graph with nodes that are connected with directed edges.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
66 There is only a single node base class and every node has an associated graph object that does not change during the node's lifetime.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
67 Every node is serializable and has an id that is unique within its graph.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
68 Every edge is classified as either a control flow edge (anti-dependency) or a data flow edge (dependency) and represented as a simple pointer from the source node to the target node.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
69 There is no cycle in the graph that contains only control flow edges or only data flow edges.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
70 It is possible to replace a node with another node without traversing the full graph.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
71 \item[Extensibility:]
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
72 The compiler is extensible by adding new compiler phases and new node subclasses without modifying the compiler's sources.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
73 A node has an abstract way of expressing its effect and new compiler phases can ask compiler nodes for their properties and capabilities.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
74 \item[Detailing:]
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
75 The compilation starts with a graph that contains nodes that represent the operations of the source language (e.g., one node for an array store to an object array).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
76 During the compilation, the nodes are replaced with more detailed nodes (e.g., the array store node is split into a null check, a bounds check, a store check, and a memory access).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
77 Compiler phases can choose whether they want to work on the earlier versions of the graph (e.g., escape analysis) or on later versions (e.g., null check elimination).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
78 \item[Generality:]
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
79 The compiler does not require Java as its input.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
80 This is achieved by having a graph as the starting point of the compilation and not a Java bytecodes array.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
81 Building the graph from the Java bytecodes must happen before giving a method to the compiler.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
82 This enables front-ends for different languages (e.g., Ruby) to provide their own graph.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
83 Also, there is no dependency on a specific back-end, but the output of the compiler is a graph that can then be converted to a different representation in a final compiler phase.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
84 \end{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
85
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
86 \section{Milestones}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
87 The Graal compiler is developed starting from the current C1X source code base.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
88 This helps us testing the compiler at every intermediate development step on a variety of Java benchmarks.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
89 We define the following development milestones and when they are considered achieved:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
90 \begin{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
91 \item[M1:] We have a fully working Graal VM version with a stripped down C1X compiler that does not perform any optimizations.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
92 \item[M2:] We modified the high-level intermediate representation to be based on the Graal compiler graph data structure.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
93 \item[M3:] We have reimplemented and reenabled compiler optimizations in the Graal compiler that previously existed in C1X.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
94 \item[M4:] We have reintegrated the new Graal compiler into the Maxine VM and can use it as a Maxine VM bootstrapping compiler.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
95 \end{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
96
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
97 After those four milestones, we see three different possible further development directions that can be followed in parallel:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
98 \begin{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
99 \item Removal of the XIR template mechanism and replacement with a snippet mechanism that works with the Graal compiler graph.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
100 \item Improvements for Graal peak performance (loop optimizations, escape analysis, bounds check elimination, processing additional interpreter runtime feedback).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
101 \item Implementation of a prototype front-end for a scripting language (e.g., Ruby).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
102 \end{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
103
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
104 \section{Implementation}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
105
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
106
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
107 \subsection{Project Source Structure}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
108 In order to have clear interfaces between the different parts of the compiler, the code will be divided into the following source code projects:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
109 \begin{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
110 \item[Graph] contains the abstract node implementation, the graph implementation and all the associated tools and auxiliary classes.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
111 \item[Nodes] contains the node implementations, ranging from high-level to machine-level nodes.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
112 \item[GraphBuilder] contains helpers for building graphs from java bytecodes and other source representations.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
113 \item[Assembler] contains the assembler classes that are used to generate the compiled code of methods and stubs.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
114 \item[Optimizations] contains all the optimizations, along with different optimization plans.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
115 \item[GraalCompiler] contains the compiler, including:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
116 \begin{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
117 \item Handling of compilation phases.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
118 \item Compilation-related data structures.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
119 \item Implementation of the \emph{compiler interface} (CI).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
120 \item Register allocation.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
121 \item Machine code creation, including debug info.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
122 \item Debug output and compilation observation.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
123 \item Compiler options management.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
124 \end{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
125 \end{description}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
126
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
127 \subsection{Initial Steps}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
128 \begin{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
129 \item Restructuring of the project to include the compiler and the modified HotSpot code within one repository. The CRI project will remain in the Maxine repository, because it will remain mostly unchanged.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
130 \item Stripping optimizations from the existing compiler, they will be reimplemented later on using the new infrastructure.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
131 \item Creating Node and Graph classes, along with the necessary auxiliary classes.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
132 \item Writing documentation on the design of the compiler.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
133 \item Use the Node class as the superclass of the existing Value class.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
134 \item Identify (and later: remove) extended bytecodes.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
135 \item Implement the new frame state concept.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
136 \item Remove LIR - in the long run there should only be one IR, which will be continually lowered until only nodes that can be translated into machine code remain.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
137 \end{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
138
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
139 \subsection{Nodes and Graphs}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
140 The most important aspect of a compiler is the data structure that holds information about an executable piece of code, called \emph{intermediate representation}~(IR).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
141 The IR used in the Graal Compiler (simply refered to as \emph{the compiler} in the rest of this document) was designed in such a way as to allow for extensive optimizations, easy traversal, compact storage and efficient processing.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
142
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
143 \subsubsection{The Node Data Structure}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
144 \begin{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
145 \item Each node is always associated with a graph.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
146 \item Each node has an immutable id which is unique within its associated graph.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
147 \item Nodes represent either operations on values or control flow operations.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
148 \item Nodes can have a data dependency, which means that one node requires the result of some other node as its input. The fact that the result of the first node needs to be computed before the second node can be executed introduces a partial order to the set of nodes.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
149 \item Nodes can have a control flow dependency, which means that the execution of one node depends on some other node. This includes conditional execution, memory access serialization and other reasons, and again introduces a partial order to the set of nodes.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
150 \item Nodes can only have data and control dependencies to nodes which belong to the same graph.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
151 \item Control dependencies and data dependencies each represent a \emph{directed acyclic graph} (DAG) on the same set of nodes. This means that data dependencies always point upwards, and control dependencies always point downwards. Situations that are normally incurr cycles (like loops) are represented by special nodes (like LoopEnd).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
152 \item Ordering between nodes is specified only to the extent which is required to correctly express the semantics of a given program. Some compilers (notably the HotSpot client compiler) always maintain a complete order for all nodes (called \emph{scheduling}), which impedes advanced optimizations. For algorithms that require a fixed ordering of nodes, a temporary schedule can always be generated.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
153 \item Both data and control dependencies can be traversed in both directions, so that each node can be traversed in four directions:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
154 \begin{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
155 \item \emph{inputs} are all nodes that this node has data dependencies on.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
156 \item \emph{usages} are all nodes that have data dependencies on this node, this is regarded as the inverse of inputs.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
157 \item \emph{successors} are all nodes that have a control dependency on this node.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
158 \item \emph{predecessors} are all nodes that this node has control dependencies on, this is regarded as the inverse of successors.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
159 \end{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
160 \item Only inputs and successors can be changed, and changes to them will update the usages and predecessors.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
161 \item The Node class needs to provide facilities for subclasses to perform actions upon cloning, dependency changes, etc.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
162 \item Nodes cannot be reassigned to another graph, they are cloned instead
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
163 \end{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
164
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
165 \subsubsection{The Graph Data Structure}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
166 \begin{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
167 \item A graph deals out ids for new nodes and can be queried for the node corresponding to a given id.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
168 \item Graphs can manage side data structures, which will be automatically invalidated and lazily recomputed whenever the graph changes. Examples for side data structures are dominator trees and temporary schedules. These side data structures will usually be understood by more than one optimization.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
169 \item Graphs are
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
170 \end{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
171
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
172 \subsection{Frame States}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
173 Frame states capture the state of the program, in terms of the source representation (e.g., Java state: local variables, expressions, ...).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
174 Whenever a safepoint is reached or the a deoptimization is needed a valid frame state needs to be available.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
175 A frame state is valid as long as the program performs only actions that can safely be reexecuted (e.g., operations on local variables, etc.).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
176 Thus, frame states need only be generated for bytecodes that can not be reexecuted: putfield, astore, invoke, monitorenter/exit, ...
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
177
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
178 Within the node graph a frame state is represented as a node that is fixed between the node that caused it to be generated (data dependency) and the node that will invalidate it (control dependency).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
179
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
180 Deopmization nodes are not fixed to a certain frame state node, they can move around freely and will always use the correct frame state.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
181 At some point during the compilation deoptimization nodes need to be fixed, which means that appropriate data and control dependencies will be inserted so that it can not move outside the scope of the associated frame state.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
182 This will generate deoptimization-free zones that can be targeted by the most aggressive optimizations.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
183
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
184 Frame states should be represented using a delta-encoding.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
185 This will make them significantly smaller and will make inlining, etc. much easier.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
186 In later compilation phases unnecessary frame states might be removed, using a mark-and-merge algorithm.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
187
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
188
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
189
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
190 \subsection{Graph Building}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
191 \begin{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
192 \item The graph built by the initial parser (called \emph{GraphBuilder}) should be as close to the source representation (bytecode, ...) as possible.
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
193 \item All nodes should be able to immediately lower themselves to a machine-level representation. This allows for easier compiler development, and also leads to a compiler that is very flexible in the amount of optimizations it performs (e.g. recompilation of methods with more aggressive optimizations).
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
194 \item
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
195 \end{itemize}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
196
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
197 \subsection{Graphical Representation}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
198 The graphs in this document use the following node layout:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
199
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
200 \begin{digraphenv}{scale=0.5}{layout01}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
201 \node{node1}{nop}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
202 \nodebi{node2}{+}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
203 \nodetri{node3}{phi}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
204 \nodesplit{node4}{if}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
205 \end{digraphenv}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
206
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
207 Red arrows always represents control dependencies, while black arrows represent data dependencies:
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
208
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
209 \begin{digraphenv}{scale=0.5}{layout1}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
210 \node{a}{a}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
211 \node{b}{b}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
212 \nodesplit{if}{if}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
213 \node{nop}{nop}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
214 \nodebi{add}{+}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
215 \controllabel{if:succ1}{nop}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
216 \controllabel{if:succ2}{add}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
217 \datalabel{add:in1}{a}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
218 \datalabel{add:in2}{b}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
219 \end{digraphenv}
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
220
765dd54244a6 Updated doc. Added Texclipse project.
Thomas Wuerthinger <thomas@wuerthinger.net>
parents: 2517
diff changeset
221
2517
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
222
8c6e31c62fba added initial version of design docs, fixed .hgignore (regex, . -> \.)
Lukas Stadler <lukas.stadler@jku.at>
parents:
diff changeset
223 \end{document}