Add support for unimplemented esil instructions

[sushant94]

Currently the following still need to be implemented:

• [ ] GOTO
• [ ] TODO
• [ ] LOOP
• [ ] BREAK
• [ ] $

[radare]

Max prio imho

On 12 Jul 2016, at 23:55, Sushant Dinesh notifications@github.com wrote:

Currently the following still need to be implemented:

GOTO TODO LOOP BREAK $ — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub, or mute the thread.

[ZhangZhuoSJTU]

About the unimplemented opcode, I have some ideas about them.

• [x] STACK: Add a public member to expose access to inside stack.
• [ ] GOTO: After checking the source code of radare, I found nowadays ESIL guaranteed the previous opcode of GOTO must be an EConstant. So we could regard EGoto as an unary opcode. As for radeco-lib or other projects, we could add control flow edge from this token.
• [x] LOOP: Equal to 0,GOTO
• [x] TODO and BREAK: We could just throw these tokens, and in other projects like radeco-lib, adding a new function for them is the best way I could think out.
• [x] $ and TRAP: they are similar with above opcodes, except that they are unary opcode.
• [x] CLEAR: It's easy to handle, by clearing parser's stack and tstack, imo.

I would like to do this in #9