fuzz: Add fuzzer for ConditionStack #18127

1. 
   MarcoFalke commented at 3:05 pm on February 12, 2020: member

   This takes the ConditionStack from d0e8f4d5d8ddaccb37f98b7989fb944081e41ab8 and e6e622e5a0e22c2ac1b50b96af818e412d67ac54 and checks that they behave equally with a fuzz test.
2. Benchmark script verification with 100 nested IFs 89fb241c54
3. [refactor] interpreter: define interface for vfExec

   Includes comments added by Pieter Wuille.

   d0e8f4d5d8
4. Implement O(1) OP_IF/NOTIF/ELSE/ENDIF logic

   This optimization was first suggested by Sergio Demian Lerner in
   https://bitslog.wordpress.com/2017/04/17/new-quadratic-delays-in-bitcoin-scripts/.
   The implementation follows the suggested approach there, but with a slightly
   simpler representation.

   e6e622e5a0
5. fuzz: Add fuzzer for ConditionStack faabdea539
6. 
   practicalswift commented at 3:15 pm on February 12, 2020: contributor

   Concept ACK: thanks for adding fuzzing harnesses. Nice to see the new PR title prefix fuzz: :)
7. DrahtBot added the label Build system on Feb 12, 2020
8. DrahtBot added the label Consensus on Feb 12, 2020
9. DrahtBot added the label Tests on Feb 12, 2020
10. 
    Empact commented at 4:48 pm on February 12, 2020: member

    Concept ACK - I take it you don’t mean for this to be merged but rather to prove the point?
11. 
    jonatack commented at 5:35 pm on February 12, 2020: member

    Concept ACK, tested

     0(pr/18127)$ src/test/fuzz/script_condition_stack 
     1INFO: Seed: 3449044402
     2INFO: Loaded 1 modules   (510932 inline 8-bit counters): 510932 [0x5642d9dc1678, 0x5642d9e3e24c), 
     3INFO: Loaded 1 PC tables (510932 PCs): 510932 [0x5642d9e3e250,0x5642da609f90), 
     4INFO: -max_len is not provided; libFuzzer will not generate inputs larger than 4096 bytes
     5INFO: A corpus is not provided, starting from an empty corpus
     6[#2](/bitcoin-bitcoin/2/)	INITED cov: 177 ft: 178 corp: 1/1b exec/s: 0 rss: 117Mb
     7[#3](/bitcoin-bitcoin/3/)	NEW    cov: 179 ft: 242 corp: 2/59b exec/s: 0 rss: 117Mb L: 58/58 MS: 1 InsertRepeatedBytes-
     8[#4](/bitcoin-bitcoin/4/)	NEW    cov: 179 ft: 290 corp: 3/90b exec/s: 0 rss: 117Mb L: 31/58 MS: 1 EraseBytes-
     9[#5](/bitcoin-bitcoin/5/)	NEW    cov: 179 ft: 291 corp: 4/121b exec/s: 0 rss: 117Mb L: 31/58 MS: 1 ChangeByte-
    10[#6](/bitcoin-bitcoin/6/)	REDUCE cov: 179 ft: 291 corp: 4/111b exec/s: 0 rss: 117Mb L: 21/58 MS: 1 EraseBytes-
    11[#7](/bitcoin-bitcoin/7/)	REDUCE cov: 179 ft: 291 corp: 4/99b exec/s: 0 rss: 117Mb L: 19/58 MS: 1 EraseBytes-
    12	NEW_FUNC[0/10]: 0x5642d6f4b1d0 in std::_Bvector_base<std::allocator<bool> >::_Bvector_impl::_M_end_addr() const /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_bvector.h:487
    13	NEW_FUNC[1/10]: 0x5642d6f4b880 in std::vector<bool, std::allocator<bool> >::_M_insert_aux(std::_Bit_iterator, bool) /usr/lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/vector.tcc:843
    14
    15.../...
    16
    17[#24489](/bitcoin-bitcoin/24489/)	REDUCE cov: 438 ft: 2252 corp: 118/178Kb exec/s: 9 rss: 264Mb L: 2263/4096 MS: 2 InsertRepeatedBytes-EraseBytes-
    

12. MarcoFalke closed this on Feb 12, 2020

    ---

13. MarcoFalke deleted the branch on Feb 12, 2020
14. 
    practicalswift commented at 9:57 pm on February 12, 2020: contributor

    @MarcoFalke Why the close?
15. DrahtBot locked this on Feb 15, 2022

Contributors
MarcoFalke practicalswift Empact jonatack

Labels
Build system Tests Consensus