[DWARF] Avoid reprocessing types repeated in every compilation unit - #8406
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bdash wants to merge 4 commits into
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[DWARF] Avoid reprocessing types repeated in every compilation unit#8406bdash wants to merge 4 commits into
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Every anonymous subroutine type produces the same placeholder regardless of its return type, because a named type reference takes only its class, width and alignment from its target, and function types set neither.
A placeholder is fully determined by its name plus the class, structure variant, width and alignment of its target, which are the only things `InitNamedType` reads from it.
The name was recorded after the branches that commit it, so it was also recorded on the two paths that log an error and commit nothing. That dated from when there was a single commit path and the two were the same event. A name left behind by a failed commit made a later type of that name get deconflicted against something that was never stored.
negasora
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Aug 12, 2026
…ration Debug info describes a type in every compilation unit that includes its header. Committing each occurrence made the core walk the whole member tree and re-resolve every named reference in it. Only the first occurrence is committed now, and later ones describing the same definition are skipped. A typedef's own type is the self-referential placeholder that stands in for it while its children are built, so the comparison uses the target that gets committed instead.
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Placeholders are built once per type rather than per declaration, and a definition already committed under its name is not committed again.
This decreases the number of types that the DWARF processor attempts to define on the view by two orders of magnitudes in some cases. Previously the duplicates were discarded by core within
DefineTypes, but not before expensive work had been performed on each submitted type.