Compiler nondeterministic behaviour

Question

Compiler nondeterministic behaviour

delitrem opened this issue a month ago · comments

Describe the bug
Compiler sometimes generates different beams for some sources.
(It seems this behaviour is somehow related to -doc() attributes and maps in beams.)

To Reproduce

$ cd path/to/erlang/otp
$ for a in $(seq 1 10); do make; md5sum lib/ssh/ebin/ssh_sftp.beam >> ../result.txt; rm lib/ssh/ebin/ssh_sftp.beam; done
$ cat ../result.txt
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
d4f1dc07cd63e00170723af6e174eee2  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam
186705d7c040a85b938c7871305c34fe  lib/ssh/ebin/ssh_sftp.beam

Expected behavior
Compiler generates the same data.

Affected versions
OTP-27.0, git master.

Michael Truog · Answer 1 · Fri Jun 14 2024 10:39:19 GMT+0800 (China Standard Time)

If you use the configure flag --enable-deterministic-build that shouldn't happen.

Igor Goryachev · Answer 2 · Fri Jun 14 2024 15:06:02 GMT+0800 (China Standard Time)

The same behaviour with ./configure --enable-deterministic-build.

Igor Goryachev · Answer 3 · Mon Jun 17 2024 05:31:04 GMT+0800 (China Standard Time)

After applying provided patch, then updating bootstrap, everything works as expected.

Lukas Larsson · Answer 4 · Thu Jun 20 2024 21:47:08 GMT+0800 (China Standard Time)

Fix will be part of OTP-27.0.1.