Avoid .debug_str lookups.
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Authored by markj on Jun 25 2019, 4:24 PM.

Details

Reviewers

emaste
jkoshy_users.sourceforge.net
kaiw

Commits

rS349424: libdwarf: Use the cached strtab pointer when reading string attributes.

Summary

libdwarf caches a string table handle, use that instead. This provides
a noticeable speedup when iterating through DIEs, since we would
otherwise do a linear search of all of the DWARF sections looking for
".debug_str" using strcmp().

Diff Detail

Repository

rS FreeBSD src repository - subversion

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Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

markj created this revision.Jun 25 2019, 4:24 PM

Harbormaster completed remote builds in B25039: Diff 59013.Jun 25 2019, 4:24 PM

markj added reviewers: emaste, jkoshy_users.sourceforge.net, kaiw.Jun 25 2019, 4:25 PM

Presumably _dwarf_strtab_init is guaranteed to be called?

In D20759#449026, @emaste wrote:

Presumably _dwarf_strtab_init is guaranteed to be called?

The only way it won't be called is if an earlier error occurs during initialization. If there is no string table, then the assertion in the removed code would fail.

emaste accepted this revision.Jun 25 2019, 7:58 PM

This revision is now accepted and ready to land.Jun 25 2019, 7:58 PM

Closed by commit rS349424: libdwarf: Use the cached strtab pointer when reading string attributes. (authored by markj). · Explain WhyJun 26 2019, 4:38 PM

This revision was automatically updated to reflect the committed changes.

markj added a commit: rS349424: libdwarf: Use the cached strtab pointer when reading string attributes..

Herald added a subscriber: imp. · View Herald TranscriptJun 26 2019, 4:38 PM

dim mentioned this in rS367466: Sync up elftoolchain with head, except for the capsicum-related commits,.Nov 7 2020, 11:58 PM