[PATCH] D153058: [clang][CFG] Support construction of a weak topological ordering of the CFG.

[Yitzhak Mandelbaum via Phabricator via cfe-commits]

ymandel marked 2 inline comments as done.
ymandel added inline comments.


================
Comment at: clang/lib/Analysis/IntervalPartition.cpp:121
+    Index.emplace(N, ID);
+  Graph.Intervals.emplace_back(ID, Header, std::move(Data.Nodes));
 }
----------------
xazax.hun wrote:
> It would probably take for me some time to understand what is going on here, but I think this part might worth a comment. In particular, I have the impression that `Graph.Intervals` is the owner of all the intervals. But we use pointers to refer to these intervals. What would guarantee that those pointers are not being invalidated by this `emplace_back` operations?
Excellent question, not least because I *wasn't* careful the first around and indeed ran up against this as a memory bug. :) That's the reason I added IDs, so that I could _avoid_ taking the addresses of elements until after we finish growing the vector. See lines 148-165: after we finish building the intervals, we go through and take addresses.

I can add comments to this effect, but perhaps the safe option is to use a std::dequeue. What do you think?


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D153058/new/

https://reviews.llvm.org/D153058