FGyama

FGyama, or Flow Graph yama is a static source code analyzer that extracts an interprocedural dataflow graph from Java source code. It's designed to be scalable so that it can be applied to a large code base.

What It Does

Input

public class Hello {
    public static void main(String[] args) {
        String name = args[0];
        System.out.println("Hello, "+name);
    }
}

Output (SVG)

<img src="docs/img/Hello.svg">

Output (XML)

<?xml version="1.0" encoding="UTF-8"?><fgyama>
  <class extends="Ljava/lang/Object;" name="LHello;" path="/home/euske/work/r/fgyama/tests/Hello.java">
    <method id="LHello;.&lt;clinit&gt;()V" name="&lt;clinit&gt;" style="initializer">
      <ast end="141" start="0" type="55"/>
      <scope name="LHello;.&lt;clinit&gt;"/>
    </method>
    <method id="LHello;.main([Ljava/lang/String;)V" name="main" style="static">
      <ast end="139" start="25" type="31"/>
      <scope name="LHello;.:main:25:139">
        <node id="M2_main_N1" kind="input" ref="#arg0" type="[Ljava/lang/String;">
          <ast end="62" start="49" type="44"/>
        </node>
        <node id="M2_main_N2" kind="assign_var" ref="$LHello;.:main:25:139/$args" type="[Ljava/lang/String;">
          <ast end="62" start="49" type="44"/>
          <accept src="M2_main_N1"/>
        </node>
        <node id="M2_main_N3" kind="input" ref="#this" type="LHello;"/>
        <node id="M2_main_N4" kind="input" ref="%Ljava/lang/String;" type="Ljava/lang/String;"/>
        <node id="M2_main_N5" kind="input" ref="@Ljava/lang/System;/.out" type="Ljava/io/PrintStream;"/>
        <scope name="LHello;.:main:25:139.:B:64:139">
          <node id="M2_main_N6" kind="ref_var" ref="$LHello;.:main:25:139/$args" type="[Ljava/lang/String;">
            <ast end="85" start="81" type="42"/>
            <accept src="M2_main_N2"/>
          </node>
          <node data="0" id="M2_main_N7" kind="value" type="I">
            <ast end="87" start="86" type="34"/>
          </node>
          <node id="M2_main_N8" kind="ref_array" ref="%Ljava/lang/String;" type="Ljava/lang/String;">
            <ast end="88" start="81" type="2"/>
            <accept label="array" src="M2_main_N6"/>
            <accept label="index" src="M2_main_N7"/>
            <accept src="M2_main_N4"/>
          </node>
          <node id="M2_main_N9" kind="assign_var" ref="$LHello;.:main:25:139.:B:64:139/$name" type="Ljava/lang/String;">
            <ast end="88" start="74" type="59"/>
            <accept src="M2_main_N8"/>
          </node>
          <node id="M2_main_N10" kind="ref_field" ref="@Ljava/lang/System;/.out" type="Ljava/io/PrintStream;">
            <ast end="108" start="98" type="40"/>
            <accept src="M2_main_N5"/>
          </node>
          <node data="Hello, " id="M2_main_N11" kind="value" type="Ljava/lang/String;">
            <ast end="126" start="117" type="45"/>
          </node>
          <node id="M2_main_N12" kind="ref_var" ref="$LHello;.:main:25:139.:B:64:139/$name" type="Ljava/lang/String;">
            <ast end="131" start="127" type="42"/>
            <accept src="M2_main_N9"/>
          </node>
          <node data="+" id="M2_main_N13" kind="op_infix" type="Ljava/lang/String;">
            <ast end="131" start="117" type="27"/>
            <accept label="L" src="M2_main_N11"/>
            <accept label="R" src="M2_main_N12"/>
          </node>
          <node data="Ljava/io/PrintStream;.println(Ljava/lang/String;)V" id="M2_main_N14" kind="call" type="V">
            <ast end="132" start="98" type="32"/>
            <accept label="#this" src="M2_main_N10"/>
            <accept label="#arg0" src="M2_main_N13"/>
          </node>
          <node id="M2_main_N15" kind="receive" type="V">
            <ast end="132" start="98" type="32"/>
            <accept src="M2_main_N14"/>
          </node>
        </scope>
      </scope>
    </method>
  </class>
</fgyama>

Node types (kinds):

Basic Operations

| Kind | Data | Input(s) | | ------------ | ------------------- | -------------------------------| | value | Actual value | | | valueset | Value count | value0, value1, ... | | op_assign | Assignment operator | L, R | | op_prefix | Prefix operator | (default) | | op_infix | Infix operator | L, R | | op_postfix | Postfix operator | (default) | | op_typecast | Casting type | (default) | | op_typecheck | Checking type | (default) | | op_iter | | (default) | | ref_var | | (default) | | ref_array | | (default), array, index | | ref_field | | (default), obj | | assign_var | | (default) | | assign_array | | (default), array, index | | assign_field | | (default), obj |

Function Call

| Kind | Data | Input(s) | | ------------ | ------------------- | -------------------------------| | call | Method IDs | @type, #arg0, ..., #bypass, .field, %type | | new | Method ID | @type, #arg0, ..., #bypass, .field, %type | | input | | | | output | | (default) | | return | | (default) | | receive | | (default), Fields | | throw | | !type | | catch | | exc0, ... | | catchjoin | | !type |

Control Flow

| Kind | Data | Input(s) | | ------------ | ------------------- | -------------------------------| | join | | cond, true, false | | begin | Loop ID | init, cont | | end | Loop ID | (default), cond, _repeat | | repeat | Loop ID | (default), _end | | case | Label count | (default), match0, ... |

How to Build

Prerequisites

• Java/Maven
• Eclipse JDT (automatically downloaded)
• Graphviz http://graphviz.org/

Compiling

$ mvn clean package

Testing

$ mvn exec:java -Dexec.args="./tests/Hello.java" > Hello.graph
or
$ ./tools/java2df.sh ./tests/Hello.java > Hello.graph
then
$ python tools/graph2gv.py Hello.graph | dot -Tsvg > Hello.svg

How to Use

XmlExporter exporter = new XmlExporter(System.out);
Java2DF converter = new Java2DF();
converter.loadDefaults();       // Load the standard classes.
converter.loadJarFile("path/to/my.jar");        // Add a jar.
converter.addSourceFile("path/to/Hello.java");  // Add a source code.
// Perform analysis for every user-defined class.
for (DFSourceKlass klass : converter.getSourceKlasses()) {
    converter.analyzeKlass(exporter, klass);
}
exporter.close();

Options

• -v: increases verbosity.
• -i filelist: takes a filename list.
• -o output: specifies the output file.
• -C classpath: add a jar file / directory to the classpath.
• -S: strict mode. (stops at a first error)
• -F: pretty printing XML.

Development

Coding style

(c-add-style "me"
         '("Java"
           (c-offsets-alist . (
                               (arglist-cont . c-lineup-argcont)
                               (arglist-intro . +)
                               ))
           ))

TODOs

• Handle consecutive SwitchCases.
• Correct local scope handling.
• Java language spec.: https://docs.oracle.com/javase/specs/
• Moar unittests.