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The result of Fallback loses some bytecode information #880

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meiMingle opened this issue Nov 18, 2024 · 2 comments
Closed

The result of Fallback loses some bytecode information #880

meiMingle opened this issue Nov 18, 2024 · 2 comments
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4.X bug

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@meiMingle
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https://repo1.maven.org/maven2/com/taobao/arthas/arthas-core/4.0.3/arthas-core-4.0.3.jar
Class: com.taobao.arthas.core.Arthas
Method: attachAgent
By comparing the results below, we can see that Fallback loses the bytecode information before L0.

This is the result of Fallback Decompiler:

  private void attachAgent(Configure configure) throws Exception {
        /*
        L0
         LINENUMBER 122 L0
         ALOAD 3
         ALOAD 7
         NEW java/lang/StringBuilder
         DUP
         INVOKESPECIAL java/lang/StringBuilder.<init> ()V
         ALOAD 1
        L31
         LINENUMBER 123 L31
         INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.getArthasCore ()Ljava/lang/String;
         INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
         LDC ";"
         INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
         ALOAD 1
         INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.toString ()Ljava/lang/String;
         INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
         INVOKEVIRTUAL java/lang/StringBuilder.toString ()Ljava/lang/String;
        L32
         LINENUMBER 122 L32
         INVOKEVIRTUAL com/sun/tools/attach/VirtualMachine.loadAgent (Ljava/lang/String;Ljava/lang/String;)V
        L1
         LINENUMBER 143 L1
         GOTO L5
        L2
         LINENUMBER 124 L2
        FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine java/util/Properties java/lang/String java/lang/String java/lang/String] [java/io/IOException]
         ASTORE 8
        L33
         LINENUMBER 125 L33
         ALOAD 8
         INVOKEVIRTUAL java/io/IOException.getMessage ()Ljava/lang/String;
         IFNULL L34
         ALOAD 8
         INVOKEVIRTUAL java/io/IOException.getMessage ()Ljava/lang/String;
         LDC "Non-numeric value found"
         INVOKEVIRTUAL java/lang/String.contains (Ljava/lang/CharSequence;)Z
         IFEQ L34
        L35
         LINENUMBER 126 L35
         ALOAD 8
         INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/Throwable;)V
        L36
         LINENUMBER 127 L36
         LDC "It seems to use the lower version of JDK to attach the higher version of JDK."
         INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
        L37
         LINENUMBER 128 L37
         LDC "This error message can be ignored, the attach may have been successful, and it will still try to connect."
         INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
         GOTO L38
        L34
         LINENUMBER 131 L34
        FRAME APPEND [java/io/IOException]
         ALOAD 8
         ATHROW
        L38
         LINENUMBER 143 L38
        FRAME CHOP 1
         GOTO L5
        L3
         LINENUMBER 133 L3
        FRAME SAME1 com/sun/tools/attach/AgentLoadException
         ASTORE 8
        L39
         LINENUMBER 134 L39
         LDC "0"
         ALOAD 8
         INVOKEVIRTUAL com/sun/tools/attach/AgentLoadException.getMessage ()Ljava/lang/String;
         INVOKEVIRTUAL java/lang/String.equals (Ljava/lang/Object;)Z
         IFEQ L40
        L41
         LINENUMBER 136 L41
         ALOAD 8
         INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/Throwable;)V
        L42
         LINENUMBER 137 L42
         LDC "It seems to use the higher version of JDK to attach the lower version of JDK."
         INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
        L43
         LINENUMBER 138 L43
         LDC "This error message can be ignored, the attach may have been successful, and it will still try to connect."
         INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
         GOTO L5
        L40
         LINENUMBER 141 L40
        FRAME APPEND [com/sun/tools/attach/AgentLoadException]
         ALOAD 8
         ATHROW
        L5
         LINENUMBER 145 L5
        FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine] []
         ACONST_NULL
         ALOAD 3
         IF_ACMPEQ L44
        L45
         LINENUMBER 146 L45
         ALOAD 3
         INVOKEVIRTUAL com/sun/tools/attach/VirtualMachine.detach ()V
         GOTO L44
        L6
         LINENUMBER 145 L6
        FRAME SAME1 java/lang/Throwable
         ASTORE 9
        L7
         ACONST_NULL
         ALOAD 3
         IF_ACMPEQ L46
        L47
         LINENUMBER 146 L47
         ALOAD 3
         INVOKEVIRTUAL com/sun/tools/attach/VirtualMachine.detach ()V
        L46
         LINENUMBER 148 L46
        FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine T T T T T java/lang/Throwable] []
         ALOAD 9
         ATHROW
        L44
         LINENUMBER 149 L44
        FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine] []
         RETURN
        L48
         LOCALVARIABLE pid Ljava/lang/String; L13 L14 5
         LOCALVARIABLE descriptor Lcom/sun/tools/attach/VirtualMachineDescriptor; L12 L14 4
         LOCALVARIABLE e Ljava/io/IOException; L33 L38 8
         LOCALVARIABLE ex Lcom/sun/tools/attach/AgentLoadException; L39 L5 8
         LOCALVARIABLE targetSystemProperties Ljava/util/Properties; L20 L5 4
         LOCALVARIABLE targetJavaVersion Ljava/lang/String; L21 L5 5
         LOCALVARIABLE currentJavaVersion Ljava/lang/String; L22 L5 6
         LOCALVARIABLE arthasAgentPath Ljava/lang/String; L29 L5 7
         LOCALVARIABLE this Lcom/taobao/arthas/core/Arthas; L8 L48 0
         LOCALVARIABLE configure Lcom/taobao/arthas/core/config/Configure; L8 L48 1
         LOCALVARIABLE virtualMachineDescriptor Lcom/sun/tools/attach/VirtualMachineDescriptor; L9 L48 2
         LOCALVARIABLE virtualMachine Lcom/sun/tools/attach/VirtualMachine; L4 L48 3
         MAXSTACK = 6
         MAXLOCALS = 10
        */
        throw new RuntimeException("Stub method");
    }

This is the result of Byte Code Analyzer

 private attachAgent(Lcom/taobao/arthas/core/config/Configure;)V throws java/lang/Exception
    TRYCATCHBLOCK L0 L1 L2 java/io/IOException
    TRYCATCHBLOCK L0 L1 L3 com/sun/tools/attach/AgentLoadException
    TRYCATCHBLOCK L4 L5 L6 null
    TRYCATCHBLOCK L6 L7 L6 null
   L8
    LINENUMBER 89 L8
    ACONST_NULL
    ASTORE 2
   L9
    LINENUMBER 90 L9
    INVOKESTATIC com/sun/tools/attach/VirtualMachine.list ()Ljava/util/List;
    INVOKEINTERFACE java/util/List.iterator ()Ljava/util/Iterator; (itf)
    ASTORE 3
   L10
   FRAME APPEND [com/sun/tools/attach/VirtualMachineDescriptor java/util/Iterator]
    ALOAD 3
    INVOKEINTERFACE java/util/Iterator.hasNext ()Z (itf)
    IFEQ L11
    ALOAD 3
    INVOKEINTERFACE java/util/Iterator.next ()Ljava/lang/Object; (itf)
    CHECKCAST com/sun/tools/attach/VirtualMachineDescriptor
    ASTORE 4
   L12
    LINENUMBER 91 L12
    ALOAD 4
    INVOKEVIRTUAL com/sun/tools/attach/VirtualMachineDescriptor.id ()Ljava/lang/String;
    ASTORE 5
   L13
    LINENUMBER 92 L13
    ALOAD 5
    ALOAD 1
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.getJavaPid ()J
    INVOKESTATIC java/lang/Long.toString (J)Ljava/lang/String;
    INVOKEVIRTUAL java/lang/String.equals (Ljava/lang/Object;)Z
    IFEQ L14
   L15
    LINENUMBER 93 L15
    ALOAD 4
    ASTORE 2
   L16
    LINENUMBER 94 L16
    GOTO L11
   L14
    LINENUMBER 96 L14
   FRAME SAME
    GOTO L10
   L11
    LINENUMBER 97 L11
   FRAME CHOP 1
    ACONST_NULL
    ASTORE 3
   L4
    LINENUMBER 99 L4
    ACONST_NULL
    ALOAD 2
    IF_ACMPNE L17
   L18
    LINENUMBER 100 L18
    NEW java/lang/StringBuilder
    DUP
    INVOKESPECIAL java/lang/StringBuilder.<init> ()V
    LDC ""
    INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
    ALOAD 1
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.getJavaPid ()J
    INVOKEVIRTUAL java/lang/StringBuilder.append (J)Ljava/lang/StringBuilder;
    INVOKEVIRTUAL java/lang/StringBuilder.toString ()Ljava/lang/String;
    INVOKESTATIC com/sun/tools/attach/VirtualMachine.attach (Ljava/lang/String;)Lcom/sun/tools/attach/VirtualMachine;
    ASTORE 3
    GOTO L19
   L17
    LINENUMBER 102 L17
   FRAME APPEND [com/sun/tools/attach/VirtualMachine]
    ALOAD 2
    INVOKESTATIC com/sun/tools/attach/VirtualMachine.attach (Lcom/sun/tools/attach/VirtualMachineDescriptor;)Lcom/sun/tools/attach/VirtualMachine;
    ASTORE 3
   L19
    LINENUMBER 105 L19
   FRAME SAME
    ALOAD 3
    INVOKEVIRTUAL com/sun/tools/attach/VirtualMachine.getSystemProperties ()Ljava/util/Properties;
    ASTORE 4
   L20
    LINENUMBER 106 L20
    ALOAD 4
    INVOKESTATIC com/taobao/arthas/common/JavaVersionUtils.javaVersionStr (Ljava/util/Properties;)Ljava/lang/String;
    ASTORE 5
   L21
    LINENUMBER 107 L21
    INVOKESTATIC com/taobao/arthas/common/JavaVersionUtils.javaVersionStr ()Ljava/lang/String;
    ASTORE 6
   L22
    LINENUMBER 108 L22
    ALOAD 5
    IFNULL L23
    ALOAD 6
    IFNULL L23
   L24
    LINENUMBER 109 L24
    ALOAD 5
    ALOAD 6
    INVOKEVIRTUAL java/lang/String.equals (Ljava/lang/Object;)Z
    IFNE L23
   L25
    LINENUMBER 110 L25
    LDC "Current VM java version: {} do not match target VM java version: {}, attach may fail."
    ICONST_2
    ANEWARRAY java/lang/Object
    DUP
    ICONST_0
    ALOAD 6
    AASTORE
    DUP
    ICONST_1
    ALOAD 5
    AASTORE
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;[Ljava/lang/Object;)V
   L26
    LINENUMBER 112 L26
    LDC "Target VM JAVA_HOME is {}, arthas-boot JAVA_HOME is {}, try to set the same JAVA_HOME."
    ICONST_2
    ANEWARRAY java/lang/Object
    DUP
    ICONST_0
    ALOAD 4
    LDC "java.home"
   L27
    LINENUMBER 113 L27
    INVOKEVIRTUAL java/util/Properties.getProperty (Ljava/lang/String;)Ljava/lang/String;
    AASTORE
    DUP
    ICONST_1
    LDC "java.home"
    INVOKESTATIC java/lang/System.getProperty (Ljava/lang/String;)Ljava/lang/String;
    AASTORE
   L28
    LINENUMBER 112 L28
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;[Ljava/lang/Object;)V
   L23
    LINENUMBER 117 L23
   FRAME APPEND [java/util/Properties java/lang/String java/lang/String]
    ALOAD 1
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.getArthasAgent ()Ljava/lang/String;
    ASTORE 7
   L29
    LINENUMBER 119 L29
    ALOAD 1
    ALOAD 7
    INVOKESTATIC com/taobao/arthas/core/Arthas.encodeArg (Ljava/lang/String;)Ljava/lang/String;
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.setArthasAgent (Ljava/lang/String;)V
   L30
    LINENUMBER 120 L30
    ALOAD 1
    ALOAD 1
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.getArthasCore ()Ljava/lang/String;
    INVOKESTATIC com/taobao/arthas/core/Arthas.encodeArg (Ljava/lang/String;)Ljava/lang/String;
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.setArthasCore (Ljava/lang/String;)V
   L0
    LINENUMBER 122 L0
    ALOAD 3
    ALOAD 7
    NEW java/lang/StringBuilder
    DUP
    INVOKESPECIAL java/lang/StringBuilder.<init> ()V
    ALOAD 1
   L31
    LINENUMBER 123 L31
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.getArthasCore ()Ljava/lang/String;
    INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
    LDC ";"
    INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
    ALOAD 1
    INVOKEVIRTUAL com/taobao/arthas/core/config/Configure.toString ()Ljava/lang/String;
    INVOKEVIRTUAL java/lang/StringBuilder.append (Ljava/lang/String;)Ljava/lang/StringBuilder;
    INVOKEVIRTUAL java/lang/StringBuilder.toString ()Ljava/lang/String;
   L32
    LINENUMBER 122 L32
    INVOKEVIRTUAL com/sun/tools/attach/VirtualMachine.loadAgent (Ljava/lang/String;Ljava/lang/String;)V
   L1
    LINENUMBER 143 L1
    GOTO L5
   L2
    LINENUMBER 124 L2
   FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine java/util/Properties java/lang/String java/lang/String java/lang/String] [java/io/IOException]
    ASTORE 8
   L33
    LINENUMBER 125 L33
    ALOAD 8
    INVOKEVIRTUAL java/io/IOException.getMessage ()Ljava/lang/String;
    IFNULL L34
    ALOAD 8
    INVOKEVIRTUAL java/io/IOException.getMessage ()Ljava/lang/String;
    LDC "Non-numeric value found"
    INVOKEVIRTUAL java/lang/String.contains (Ljava/lang/CharSequence;)Z
    IFEQ L34
   L35
    LINENUMBER 126 L35
    ALOAD 8
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/Throwable;)V
   L36
    LINENUMBER 127 L36
    LDC "It seems to use the lower version of JDK to attach the higher version of JDK."
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
   L37
    LINENUMBER 128 L37
    LDC "This error message can be ignored, the attach may have been successful, and it will still try to connect."
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
    GOTO L38
   L34
    LINENUMBER 131 L34
   FRAME APPEND [java/io/IOException]
    ALOAD 8
    ATHROW
   L38
    LINENUMBER 143 L38
   FRAME CHOP 1
    GOTO L5
   L3
    LINENUMBER 133 L3
   FRAME SAME1 com/sun/tools/attach/AgentLoadException
    ASTORE 8
   L39
    LINENUMBER 134 L39
    LDC "0"
    ALOAD 8
    INVOKEVIRTUAL com/sun/tools/attach/AgentLoadException.getMessage ()Ljava/lang/String;
    INVOKEVIRTUAL java/lang/String.equals (Ljava/lang/Object;)Z
    IFEQ L40
   L41
    LINENUMBER 136 L41
    ALOAD 8
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/Throwable;)V
   L42
    LINENUMBER 137 L42
    LDC "It seems to use the higher version of JDK to attach the lower version of JDK."
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
   L43
    LINENUMBER 138 L43
    LDC "This error message can be ignored, the attach may have been successful, and it will still try to connect."
    INVOKESTATIC com/taobao/arthas/common/AnsiLog.warn (Ljava/lang/String;)V
    GOTO L5
   L40
    LINENUMBER 141 L40
   FRAME APPEND [com/sun/tools/attach/AgentLoadException]
    ALOAD 8
    ATHROW
   L5
    LINENUMBER 145 L5
   FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine] []
    ACONST_NULL
    ALOAD 3
    IF_ACMPEQ L44
   L45
    LINENUMBER 146 L45
    ALOAD 3
    INVOKEVIRTUAL com/sun/tools/attach/VirtualMachine.detach ()V
    GOTO L44
   L6
    LINENUMBER 145 L6
   FRAME SAME1 java/lang/Throwable
    ASTORE 9
   L7
    ACONST_NULL
    ALOAD 3
    IF_ACMPEQ L46
   L47
    LINENUMBER 146 L47
    ALOAD 3
    INVOKEVIRTUAL com/sun/tools/attach/VirtualMachine.detach ()V
   L46
    LINENUMBER 148 L46
   FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine T T T T T java/lang/Throwable] []
    ALOAD 9
    ATHROW
   L44
    LINENUMBER 149 L44
   FRAME FULL [com/taobao/arthas/core/Arthas com/taobao/arthas/core/config/Configure com/sun/tools/attach/VirtualMachineDescriptor com/sun/tools/attach/VirtualMachine] []
    RETURN
   L48
    LOCALVARIABLE pid Ljava/lang/String; L13 L14 5
    LOCALVARIABLE descriptor Lcom/sun/tools/attach/VirtualMachineDescriptor; L12 L14 4
    LOCALVARIABLE e Ljava/io/IOException; L33 L38 8
    LOCALVARIABLE ex Lcom/sun/tools/attach/AgentLoadException; L39 L5 8
    LOCALVARIABLE targetSystemProperties Ljava/util/Properties; L20 L5 4
    LOCALVARIABLE targetJavaVersion Ljava/lang/String; L21 L5 5
    LOCALVARIABLE currentJavaVersion Ljava/lang/String; L22 L5 6
    LOCALVARIABLE arthasAgentPath Ljava/lang/String; L29 L5 7
    LOCALVARIABLE this Lcom/taobao/arthas/core/Arthas; L8 L48 0
    LOCALVARIABLE configure Lcom/taobao/arthas/core/config/Configure; L8 L48 1
    LOCALVARIABLE virtualMachineDescriptor Lcom/sun/tools/attach/VirtualMachineDescriptor; L9 L48 2
    LOCALVARIABLE virtualMachine Lcom/sun/tools/attach/VirtualMachine; L4 L48 3
    MAXSTACK = 6
    MAXLOCALS = 10
@meiMingle
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@Col-E Should this code be removed?
image

@Col-E
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Col-E commented Nov 24, 2024

a68b8c1 👍

@Col-E Col-E closed this as completed Nov 24, 2024
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