我刚开始使用 Wala Java Slicer 来做一些源代码分析任务。我对图书馆的正确使用有疑问。假设我有以下示例代码:
public void main(String[] args) {
...
UserType ut = userType;
int i = ut.getInt();
...
System.out.println(i);
}
用 Wala 计算 println
语句的切片给出以下语句:
NORMAL_RET_CALLER:Node: < Application, LRTExecutionClass, main([Ljava/lang/String;)V > Context: Everywhere[15]13 = invokevirtual < Application, LUserType, getInt()I > 11 @27 exception:12
NORMAL main:23 = getstatic < Application, Ljava/lang/System, out, <Application,Ljava/io/PrintStream> > Node: < Application, LRTExecutionClass, main([Ljava/lang/String;)V > Context: Everywhere
NORMAL main:invokevirtual < Application, Ljava/io/PrintStream, println(I)V > 23,13 @63 exception:24 Node: < Application, LRTExecutionClass, main([Ljava/lang/String;)V > Context: Everywhere
我使用 Wala 创建切片的代码如下所示:
AnalysisScope scope = AnalysisScopeReader.readJavaScope("...",
null, WalaJavaSlicer.class.getClassLoader());
ClassHierarchy cha = ClassHierarchy.make(scope);
Iterable<Entrypoint> entrypoints = Util.makeMainEntrypoints(scope, cha);
AnalysisOptions options = new AnalysisOptions(scope, entrypoints);
// Build the call graph
CallGraphBuilder cgb = Util.makeZeroCFABuilder(options, new AnalysisCache(),cha, scope, null, null);
CallGraph cg = cgb.makeCallGraph(options, null);
PointerAnalysis pa = cgb.getPointerAnalysis();
// Find seed statement
Statement statement = findCallTo(findMainMethod(cg), "println");
// Context-sensitive thin slice
Collection<Statement> slice = Slicer.computeBackwardSlice(statement, cg, pa, DataDependenceOptions.NO_BASE_NO_HEAP, ControlDependenceOptions.NONE);
dumpSlice(slice);
我希望在切片中找到许多语句,但它们不存在:
- 即使依赖方法调用
ut.getInt()
包含在切片中,也不包含赋值语句ut = userType
- 不包含
getInt()
实现中的语句。是否有激活“程序间”切片的选项?我应该在这里提一下,.class 文件包含在用于创建AnalysisScope
的路径中。
如您所见,我使用 DataDependenceOptions.NO_BASE_NO_HEAP
和 ControlDependenceOptions.NONE
作为依赖选项。但即使我对两者都使用 FULL
,问题仍然存在。
我做错了什么?
最佳答案
The assign statement ut = userType is not included even though the dependent method call ut.getInt(), IS included in the slice
我怀疑赋值永远不会进入字节码,因为它是一个不需要的局部变量,因此对 WALA 是不可见的:
Because the SSA IR has already been somewhat optimized, some statements such as simple assignments (x=y, y=z) do not appear in the IR, due to copy propagation optimizations done automatically during SSA construction by the SSABuilder class. In fact, there is no SSA assignment instruction; additionally, a javac compiler is free to do these optimizations, so the statements may not even appear in the bytecode. Thus, these Java statements will never appear in the slice.
关于java - Wala Java Slicer - 切片中缺少语句,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/32949758/