JEB 4.1.0 wasm decompilation issue

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gree...@gmail.com

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Jun 27, 2021, 5:32:49 AMJun 27
to JEB Decompiler
Hi, I"m observing on some functions inside .wasm (WebAssembly) decompilation error
like

void __f2912() {
    // Decompilation error
}

In console window I see the following:

---
Error: Instruction cannot be converted: 50133FFEh: 0B: 0 end                              [0,0]
---
This address points right to the end of the function

I'm using this SW:
JEB 4.1.0.202106222308 (jeb-demo)

Quesiton: are there any means (eg Decompiler options fine-tuning) to  mitigate this kind of error?

PS. I"ve seen similar issues on other functions, same reason I believe...

gree...@gmail.com

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Jul 2, 2021, 6:20:31 AMJul 2
to JEB Decompiler
I see same issue on version JEB 4.2.0.202106271614

gree...@gmail.com

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Jul 3, 2021, 3:48:20 AMJul 3
to JEB Decompiler
Maybe this info will help to track down the issue?...
...
...
...
.code:50133FF3                 loc_50133FF3:    
.code:50133FF3    20 02                         0 [0]  local.get $L2                     
.code:50133FF5    10 80 01                      0 [1]  call __f1128
.code:50133FF8    1A                            0 [1]  drop
.code:50133FF9    20 01                         0 [0]  local.get $L1
.code:50133FFB    10 1D                         0 [1]  call Dr
.code:50133FFD    00                            0 [0]  unreachable
.code:50133FFE    0B                            0 [0]  end
.code:50133FFE                                  
.code:50133FFE                 __f2912          endp


maybe that "unreachable" causes JEB to malfuction

Also this stack might understand what is going on:

Error: Instruction cannot be converted: 50133FFEh: 0B: 0 end                              [0,0]
java.lang.RuntimeException: FAIL - unexpected condition
at com.pnfsoftware.jeb.corei.parsers.wasm.ar.convertBlock(SourceFile:997)
at com.pnfsoftware.jeb.core.units.code.asm.decompiler.AbstractConverter.convert(SourceFile:408)
at com.pnfsoftware.jebglobal.SM.Yz(SourceFile:56)
at com.pnfsoftware.jebglobal.Yz.Yg(SourceFile:115)
at com.pnfsoftware.jebglobal.Dz.Yg(SourceFile:134)
at com.pnfsoftware.jebglobal.Dz.Yg(SourceFile:121)
at com.pnfsoftware.jebglobal.Iq.Yg(SourceFile:545)
at com.pnfsoftware.jebglobal.Iq.Yg(SourceFile:344)
at com.pnfsoftware.jebglobal.rF.Yg(SourceFile:1127)
at com.pnfsoftware.jebglobal.rF.Yg(SourceFile:539)
at com.pnfsoftware.jebglobal.rF.Yg(SourceFile:512)
at com.pnfsoftware.jebglobal.rF.decompileToUnit(SourceFile:464)
at com.pnfsoftware.jebglobal.rF.decompileToUnit(SourceFile:128)
at com.pnfsoftware.jeb.rcpclient.handlers.HandlerUtil$2.call(HandlerUtil.java:266)
at com.pnfsoftware.jeb.rcpclient.handlers.HandlerUtil$2.call(HandlerUtil.java:257)
at com.pnfsoftware.jeb.util.concurrent.ThreadEx.run(SourceFile:52)

Nicolas Falliere

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Jul 3, 2021, 3:57:16 AMJul 3
to gree...@gmail.com, JEB Decompiler
Thank you, will look into it. Do you have a sample file to share by any chance?

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