SpecialSource reorders local variables, unlike RetroGuard (blocking MCP adaption)

SpecialSource's use of ASM rewrites the constant pool therefore reordering local variables causing patch discrepancies when compared to RetroGuard.

Example comparing SpecialSource to RetroGuard (as used in MCP):

diff -ur src/minecraft/net/minecraft/server/MinecraftServer.java src-/minecraft/net/minecraft/server/MinecraftServer.java
--- src/minecraft/net/minecraft/server/MinecraftServer.java     2013-03-10 18:51:56.000000000 -0700
+++ src-/minecraft/net/minecraft/server/MinecraftServer.java    2013-03-10 18:50:08.000000000 -0700
@@ -137,17 +137,17 @@ (near "menu.loadingLevel")
       this.field_71305_c = new WorldServer[3];
       this.field_71312_k = new long[this.field_71305_c.length][100];
       ISaveHandler var7 = this.field_71310_m.func_75804_a(p_71247_1_, true);
-      WorldInfo var9 = var7.func_75757_d();
-      WorldSettings var8;
-      if(var9 == null) {
-         var8 = new WorldSettings(p_71247_3_, this.func_71265_f(), this.func_71225_e(), this.func_71199_h(), p_71247_5_);
-         var8.func_82750_a(p_71247_6_);
+      WorldInfo var8 = var7.func_75757_d();
+      WorldSettings var9;
+      if(var8 == null) {
+         var9 = new WorldSettings(p_71247_3_, this.func_71265_f(), this.func_71225_e(), this.func_71199_h(), p_71247_5_);
+         var9.func_82750_a(p_71247_6_);
       } else {
-         var8 = new WorldSettings(var9);
+         var9 = new WorldSettings(var8);
       }

more at https://gist.github.com/agaricusb/5131683 - but this difference is pervasive throughout the decompile

The vanilla (unremapped) code is as follows:

  ajz var7 = this.l.a(var1, true);
  ajp var9 = var7.d();
  aac var8;

7, 9, 8 is vanilla/RG but SS reorders to 7, 8, 9.

vanilla disassembly with javap:

     6: ldc           #55                 // String menu.loadingLevel
     8: invokevirtual #335                // Method c:(Ljava/lang/String;)V
    11: aload_0       
    12: iconst_3      
    13: anewarray     #112                // class iz
    16: putfield      #185                // Field b:[Liz;
    19: aload_0       
    20: aload_0       
    21: getfield      #185                // Field b:[Liz;
    24: arraylength   
    25: bipush        100
    27: multianewarray #80,  2            // class "[[J"
    31: putfield      #193                // Field j:[[J
    34: aload_0       
    35: getfield      #195                // Field l:Lakc;
    38: aload_1       
    39: iconst_1      
    40: invokeinterface #366,  3          // InterfaceMethod akc.a:(Ljava/lang/String;Z)Lajz;
    45: astore        7
    47: aload         7
    49: invokeinterface #363,  1          // InterfaceMethod ajz.d:()Lajp;
    54: astore        9
    56: aload         9
    58: ifnonnull     96
    61: new           #82                 // class aac

RetroGuard:

     6: ldc           #55                 // String menu.loadingLevel
     8: invokevirtual #335                // Method func_71192_d:(Ljava/lang/String;)V
    11: aload_0       
    12: iconst_3      
    13: anewarray     #112                // class net/minecraft/src/WorldServer
    16: putfield      #185                // Field field_71305_c:[Lnet/minecraft/src/WorldServer;
    19: aload_0       
    20: aload_0       
    21: getfield      #185                // Field field_71305_c:[Lnet/minecraft/src/WorldServer;
    24: arraylength   
    25: bipush        100
    27: multianewarray #80,  2            // class "[[J"
    31: putfield      #193                // Field field_71312_k:[[J
    34: aload_0       
    35: getfield      #195                // Field field_71310_m:Lnet/minecraft/src/ISaveFormat;
    38: aload_1       
    39: iconst_1      
    40: invokeinterface #366,  3          // InterfaceMethod net/minecraft/src/ISaveFormat.func_75804_a:(Ljava/lang/String;Z)Lnet/minecraft/src/ISaveHandler;
    45: astore        7
    47: aload         7
    49: invokeinterface #363,  1          // InterfaceMethod net/minecraft/src/ISaveHandler.func_75757_d:()Lnet/minecraft/src/WorldInfo;
    54: astore        9
    56: aload         9
    58: ifnonnull     96
    61: new           #82                 // class net/minecraft/src/WorldSettings

SS:

     6: ldc           #192                // String menu.loadingLevel
     8: invokevirtual #173                // Method func_71192_d:(Ljava/lang/String;)V
    11: aload_0       
    12: iconst_3      
    13: anewarray     #194                // class net/minecraft/src/WorldServer
    16: putfield      #196                // Field field_71305_c:[Lnet/minecraft/src/WorldServer;
    19: aload_0       
    20: aload_0       
    21: getfield      #196                // Field field_71305_c:[Lnet/minecraft/src/WorldServer;
    24: arraylength   
    25: bipush        100
    27: multianewarray #197,  2           // class "[[J"
    31: putfield      #199                // Field field_71312_k:[[J
    34: aload_0       
    35: getfield      #135                // Field field_71310_m:Lnet/minecraft/src/ISaveFormat;
    38: aload_1       
    39: iconst_1      
    40: invokeinterface #203,  3          // InterfaceMethod net/minecraft/src/ISaveFormat.func_75804_a:(Ljava/lang/String;Z)Lnet/minecraft/src/ISaveHandler;
    45: astore        7
    47: aload         7
    49: invokeinterface #209,  1          // InterfaceMethod net/minecraft/src/ISaveHandler.func_75757_d:()Lnet/minecraft/src/WorldInfo;
    54: astore        8
    56: aload         8
    58: ifnonnull     96
    61: new           #211                // class net/minecraft/src/WorldSettings

All of the constant references are shifted, but only local variables create a discrepancy for fernflower decompilation.

edit: actually its the local variable slots - astore 8 vs astore 9 on line 54

md-5 / SpecialSource

SpecialSource reorders local variables, unlike RetroGuard (blocking MCP adaption) #2