Summary:
In `Unix/Process.inc`, we seed a random number generator from
`/dev/urandom` if possible, but if not, we're happy to fall back to
ordinary pseudorandom strategies, like the current time and PID.
The corresponding function on Windows calls `CryptGenRandom`, but it
//doesn't// have a fallback if that strategy fails. But `CryptGenRandom`
//can// fail, if a cryptography provider isn't properly initialized, or
occasionally (by our observation) simply intermittently.
If it's reasonable on Unix to implement traditional pseudorandom-number
seeding as a fallback, then it's surely reasonable to do the same on
Windows. So this patch adds a last-ditch use of ordinary rand(), using
much the same strategy as the Unix fallback code.
Reviewers: hans, sammccall
Reviewed By: hans
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D77553
aab9e9de4d