[Lldb-commits] [PATCH] D48479: Represent invalid UUIDs as UUIDs with length zero

[Pavel Labath via Phabricator via lldb-commits]

labath created this revision.
labath added reviewers: clayborg, sas, lemo, davide.
Herald added subscribers: arichardson, emaste.
Herald added a reviewer: espindola.

During the previous attempt to generalize the UUID class, it was
suggested that we represent invalid UUIDs as length zero (previously, we
used an all-zero UUID for that). This meant that some valid build-ids
could not be represented (it's possible however unlikely that a checksum of
some file would be zero) and complicated adding support for variable
length build-ids (should a 16-byte empty UUID compare equal to a 20-byte
empty UUID?).

This patch resolves these issues by introducing a canonical
representation for an invalid UUID. The slight complication here is that
some clients (MachO) actually use the all-zero notation to mean "no UUID
has been set". To keep this use case working, I have introduced an
additional argument to the UUID constructor, which specifies whether an
all-zero vector should be considered a valid UUID. For the usages where
the UUID data comes from a MachO file, I set this argument to false.

I did not introduce a similar argument to the string parsing function
with the rationalle that if somebody went through the trouble of
spelling it out as a bunch of zeroes, he probably really means that.


https://reviews.llvm.org/D48479

Files:
  include/lldb/Utility/UUID.h
  source/API/SBModuleSpec.cpp
  source/Plugins/DynamicLoader/Darwin-Kernel/DynamicLoaderDarwinKernel.cpp
  source/Plugins/DynamicLoader/MacOSX-DYLD/DynamicLoaderMacOSXDYLD.cpp
  source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp
  source/Plugins/ObjectFile/Mach-O/ObjectFileMachO.cpp
  source/Plugins/Process/minidump/MinidumpParser.cpp
  source/Utility/DataExtractor.cpp
  source/Utility/UUID.cpp
  unittests/Process/gdb-remote/GDBRemoteCommunicationClientTest.cpp
  unittests/Utility/UUIDTest.cpp

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