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perf(libstore/derivation-builder): Futher simplify / maybe optimize

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We can precompute the exact information we need for topo sorting and
store it in `PerhapsNeedToRegister`. Depending on how `topoSort` works,
this is easy a performance improvement or just completely harmless.

Co-Authored-By: Bernardo Meurer Costa <beme@anthropic.com>
This commit is contained in:
John Ericson 2025-11-25 17:01:23 -05:00
parent 686ad9b052
commit c33b2c5834
1 changed files with 22 additions and 11 deletions
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33
src/libstore/unix/build/derivation-builder.cc
View file

@ -1396,6 +1396,11 @@ SingleDrvOutputs DerivationBuilderImpl::registerOutputs()
struct PerhapsNeedToRegister
{
StorePathSet refs;
/**
* References to other outputs. Built by looking up in
* `scratchOutputsInverse`.
*/
StringSet otherOutputs;
};
/* inverse map of scratchOutputs for efficient lookup */
@ -1471,12 +1476,24 @@ SingleDrvOutputs DerivationBuilderImpl::registerOutputs()
references = scanForReferences(blank, actualPath, referenceablePaths);
}
outputReferencesIfUnregistered.insert_or_assign(outputName, PerhapsNeedToRegister{.refs = references});
StringSet referencedOutputs;
for (auto & r : references)
if (auto * o = get(scratchOutputsInverse, r))
referencedOutputs.insert(*o);
outputReferencesIfUnregistered.insert_or_assign(
outputName,
PerhapsNeedToRegister{
.refs = references,
.otherOutputs = referencedOutputs,
});
outputStats.insert_or_assign(outputName, std::move(st));
}
auto topoSortResult = topoSort(outputsToSort, [&](const std::string & name) {
auto orifu = get(outputReferencesIfUnregistered, name);
StringSet emptySet;
auto topoSortResult = topoSort(outputsToSort, [&](const std::string & name) -> const StringSet & {
auto * orifu = get(outputReferencesIfUnregistered, name);
if (!orifu)
throw BuildError(
BuildResult::Failure::OutputRejected,
@ -1488,14 +1505,8 @@ SingleDrvOutputs DerivationBuilderImpl::registerOutputs()
/* Since we'll use the already installed versions of these, we
can treat them as leaves and ignore any references they
have. */
[&](const AlreadyRegistered &) { return StringSet{}; },
[&](const PerhapsNeedToRegister & refs) {
StringSet referencedOutputs;
for (auto & r : refs.refs)
if (auto * o = get(scratchOutputsInverse, r))
referencedOutputs.insert(*o);
return referencedOutputs;
},
[&](const AlreadyRegistered &) -> const StringSet & { return emptySet; },
[&](const PerhapsNeedToRegister & refs) -> const StringSet & { return refs.otherOutputs; },
},
*orifu);
});