RetDec recognizes GCC 7.2.0 binaries as GCC 4.6.3

[firmianay]

hi, I want to know if retdec on github and on online server have the different version. On my Arch Linux pc, gcc version is 7.2.0. And then, I try to decompile a binary.

This is the result from REST API:

// Detected compiler/packer: gcc (7.2.0)

and the result from my local build:

// Detected compiler/packer: gcc (4.6.3)

its wrong.

btw, the project is amazing!

[mbandzi]

Hello,

I believe REST API uses some older stable version of RetDec so this is a possible regression as detections are currently under development. Could you please upload mentioned binary?

[s3rvac]

@mbandzi We looked into this today for a bit with @metthal. There seems to be a regression with compiler detection. Consider the following file (32b ELF compiled with GCC 7.2.0 on Arch Linux): hello-gcc-7.2.0.elf:

$ fileinfo -s hello-gcc-7.2.0.elf
[..]
Detected tool : GCC (4.6.3) RHEL (compiler), 27 from 49 significant nibbles (55.102%)
Detected tool : GCC (7.2.0) (compiler), .comment section heuristic

When decompiled, the JSON config hello-gcc-7.2.0.c.json contains

"tools" : [
   {
      "additional" : "RHEL",
      "heuristics" : false,
      "identicalSignificantNibbles" : 27,
      [..]
      "version" : "4.6.3"
   },
   {
      "heuristics" : true,
      [..]
      "version" : "7.2.0"
   }
],

When generating the // Detected compiler/packer: comment, our back-end (llvmir2hll) chooses the first item from this list, so the compilers should be ordered by their priority.

We believe that there is a problem with the ordering of the detected compilers by their priority. In this case, the heuristic should probably have a greater priority than a signature having only 27/49 significant nibbles.

[mbandzi]

fixed in master, thanks for the report