tejohnson added a comment.
I just noticed that generateParamAccessSummary is taking a bit over 5% of the
ThinLTO thin link step in an internal build (and will soon be more than 5% as I
found another analysis that is hogging compile time that I'm going to work on
fixing). This is currently the second hottest analysis in the thin link. Is the
stack safety analysis meant to be always on with ThinLTO?
I have a theory on what is causing it to incur so much overhead, see below.
================
Comment at: llvm/lib/Analysis/StackSafetyAnalysis.cpp:913
+ FunctionSummary *S = resolveCallee(
+ Index.findSummaryInModule(Call.Callee, FS->modulePath()));
+ if (!S) {
----------------
This is doing a hash table lookup by GUID in the combined index. Can the Callee
field be changed to hold the ValueInfo instead of the GUID? Calling
findSummaryInModule on a ValueInfo avoids the hash table lookup. E.g. see how
we compute the Ref edges in ModuleSummaryAnalysis.cpp (i.e. via
getOrInsertValueInfo), and then propagate that through the bitcode.
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D81242/new/
https://reviews.llvm.org/D81242
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