[Dependency Scan] Do not pass clang's -dwarf-debug-flags to swift
#79179
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When turning on directCC1 scanning, swift will ask clang driver to expand all cc1 flags and pass that explicitly on command-line. In such case, if `RC_DEBUG_OPTIONS` env is set on darwin platform, it will cause clang driver to encode all the options it gets and pass those clang driver options as a cc1 options `-dwarf-debug-flags`. After the change, swift scanner will no longer generate a long `-Xcc -dwarf-debug-flag -Xcc <long list of flags>` for later compilation. Losing such information in DWARF doesn't affect swift debugging. It will instead, make command-line a lot shorter, save spaces in swift binary module, and make swift caching build more reliable. rdar://144267483
cachemeifyoucan
requested review from
artemcm,
zoecarver,
hyp,
egorzhdan,
beccadax,
ian-twilightcoder and
Xazax-hun
as code owners
|
@swift-ci please smoke test |
adrian-prantl
approved these changes
Feb 6, 2025
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When turning on directCC1 scanning, swift will ask clang driver to expand all cc1 flags and pass that explicitly on command-line. In such case, if
RC_DEBUG_OPTIONSenv is set on darwin platform, it will cause clang driver to encode all the options it gets and pass those clang driver options as a cc1 options-dwarf-debug-flags.After the change, swift scanner will no longer generate a long
-Xcc -dwarf-debug-flag -Xcc <long list of flags>for later compilation. Losing such information in DWARF doesn't affect swift debugging. It will instead, make command-line a lot shorter, save spaces in swift binary module, and make swift caching build more reliable.rdar://144267483