"Stacks have different current sizes" on valid bytecode #509
Description
I'm running proguard on an already obfuscated build, because the optimizer is really good. However the optimizer fails on the bytecode snipped attached below.
This is completely valid bytecode as the instruction at offset 54 can only be reached by either the ifnull at offset 6 where the stack is [aload_1] or from the goto at offset 47 which is directly after an aload_1 on empty stack, so [aload_1].
I'm also not quite sure why it expects 4 variables, as only 3 are ever used and locals is 3.
Those exceptions will also never throw, but that's one thing I was expecting proguard to clean up.
Latest github release version, so 7.8.1
error[1011]: proguard.evaluation.exception.StackGeneralizationException
--> n/u : a(Ln/c;)V at aload_0 v0
9 | goto +6
15 | aload_1 v1
16 | goto +6
22 | aload_0 v0
| ^^^^^^^^^^ Could not generalize stacks [4:P1:a] and [4:P1:a][15:P1:a] because: "Stacks have different current sizes [1] and [2]".
23 | getfield #1537
Variables: [P0:P0:a][P1:P1:a][3:M0:a][empty:empty]
Stack: [4:P1:a]
proguard.evaluation.exception.StackGeneralizationException: Could not generalize stacks [4:P1:a] and [4:P1:a][15:P1:a] because: "Stacks have different current sizes [1] and [2]".
at proguard.evaluation.PartialEvaluator.evaluateSingleInstructionBlock(PartialEvaluator.java:705) ~[proguard.jar:7.8.1]
at proguard.evaluation.PartialEvaluator.evaluateInstructionBlock(PartialEvaluator.java:624) ~[proguard.jar:7.8.1]
at proguard.evaluation.PartialEvaluator.evaluateInstructionBlockAndExceptionHandlers(PartialEvaluator.java:599) ~[proguard.jar:7.8.1]
at proguard.evaluation.PartialEvaluator.visitCodeAttribute0(PartialEvaluator.java:399) ~[proguard.jar:7.8.1]
at proguard.evaluation.PartialEvaluator.visitCodeAttribute(PartialEvaluator.java:347) ~[proguard.jar:7.8.1]
at proguard.evaluation.LivenessAnalyzer.visitCodeAttribute(LivenessAnalyzer.java:213) ~[proguard.jar:7.8.1]
at proguard.optimize.evaluation.VariableOptimizer.visitCodeAttribute(VariableOptimizer.java:103) ~[proguard.jar:7.8.1]
at proguard.optimize.info.OptimizationCodeAttributeFilter.visitCodeAttribute(OptimizationCodeAttributeFilter.java:82) ~[proguard.jar:7.8.1]
at proguard.classfile.attribute.visitor.DebugAttributeVisitor.visitCodeAttribute(DebugAttributeVisitor.java:318) ~[proguard.jar:7.8.1]
at proguard.classfile.attribute.CodeAttribute.accept(CodeAttribute.java:105) ~[proguard.jar:7.8.1]
at proguard.classfile.ProgramMethod.attributesAccept(ProgramMethod.java:118) ~[proguard.jar:7.8.1]
at proguard.classfile.attribute.visitor.AllAttributeVisitor.visitProgramMember(AllAttributeVisitor.java:77) ~[proguard.jar:7.8.1]
at proguard.classfile.visitor.MemberVisitor.visitProgramMethod(MemberVisitor.java:47) ~[proguard.jar:7.8.1]
at proguard.classfile.ProgramMethod.accept(ProgramMethod.java:113) ~[proguard.jar:7.8.1]
at proguard.classfile.ProgramClass.methodsAccept(ProgramClass.java:589) ~[proguard.jar:7.8.1]
at proguard.classfile.visitor.AllMethodVisitor.visitAnyClass(AllMethodVisitor.java:39) ~[proguard.jar:7.8.1]
at proguard.classfile.visitor.ClassVisitor.visitProgramClass(ClassVisitor.java:35) ~[proguard.jar:7.8.1]
at proguard.classfile.ProgramClass.accept(ProgramClass.java:491) ~[proguard.jar:7.8.1]
at proguard.classfile.visitor.ParallelAllClassVisitor$MyThreadedClassVisitor.lambda$submitClassToExecutorService$0(ParallelAllClassVisitor.java:153) ~[proguard.jar:7.8.1]
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) [?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
at java.base/java.lang.Thread.run(Thread.java:829) [?:?]
Caused by: java.lang.IllegalArgumentException: Stacks have different current sizes [1] and [2]
at proguard.evaluation.Stack.generalize(Stack.java:101) ~[proguard.jar:7.8.1]
at proguard.evaluation.TracedStack.generalize(TracedStack.java:118) ~[proguard.jar:7.8.1]
at proguard.evaluation.PartialEvaluator.evaluateSingleInstructionBlock(PartialEvaluator.java:703) ~[proguard.jar:7.8.1]
... 23 more
public void a(n.c);
descriptor: (Ln/c;)V
flags: (0x0001) ACC_PUBLIC
Code:
stack=2, locals=3, args_size=2
0: invokestatic #83 // Method n/t.b:()[Lo/a;
3: astore_2
4: aload_1
5: aload_2
6: ifnull 54
9: invokevirtual #1531 // Method n/c.a:()Z
12: ifeq 46
15: goto 22
18: invokestatic #120 // Method a:(Ljava/lang/IllegalArgumentException;)Ljava/lang/IllegalArgumentException;
21: athrow
22: aload_1
23: aload_0
24: getfield #1533 // Field g:Ln/c;
27: putfield #1535 // Field n/c.a:Ln/c;
30: aload_0
31: aload_1
32: putfield #1533 // Field g:Ln/c;
35: aload_2
36: ifnonnull 66
39: goto 46
42: invokestatic #120 // Method a:(Ljava/lang/IllegalArgumentException;)Ljava/lang/IllegalArgumentException;
45: athrow
46: aload_1
47: goto 54
50: invokestatic #120 // Method a:(Ljava/lang/IllegalArgumentException;)Ljava/lang/IllegalArgumentException;
53: athrow
54: aload_0
55: getfield #1537 // Field aa:Ln/c;
58: putfield #1535 // Field n/c.a:Ln/c;
61: aload_0
62: aload_1
63: putfield #1537 // Field aa:Ln/c;
66: return
Exception table:
from to target type
4 15 18 Class java/lang/IllegalArgumentException
9 39 42 Class java/lang/IllegalArgumentException
22 47 50 Class java/lang/IllegalArgumentException