cmd/link: loading N packages takes O(N²) time

[rsc]

There are some deduplication scans in the linker to avoid loading the same package (same import path) multiple times. These use a linear scan over all packages already loaded, so loading N packages takes O(N²) time (even with no duplicates). These scans should be replaced by map checks, cutting the time for N packages to O(N).

I have a CL and will send it.

[gopherbot]

CL https://golang.org/cl/44852 mentions this issue.

[odeke-em]

Hmm, how come gobot didn't close this issue when CL https://go-review.googlesource.com/c/44852/ was merged into master as 51711d1.

[bradfitz]

Maybe because Github has been having problems today? https://status.github.com/messages

[odeke-em]

Ah, gotcha.