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| author | Marc Mutz <marc.mutz@kdab.com> | 2017-11-21 10:41:45 +0100 |
|---|---|---|
| committer | Marc Mutz <marc.mutz@kdab.com> | 2017-11-30 13:18:39 +0000 |
| commit | c6497e3eac1ac81497f02b40ea7f140a997b4f29 (patch) | |
| tree | aa969b1bd80c66e790413e59195eb8b24370cf18 /src/corelib/global/qcompilerdetection.h | |
| parent | 7967c40303604bf1a02fe987ffc667e4e55d9af2 (diff) | |
Mark some functions as cold
Add Q_DECL_COLD_FUNCTION (__attribute__((cold))) to tell the compiler
that the following functions are not usually executed in normal programs:
- qWarning/qCritical/qFatal
- qTerminate
- assertion failure
- qBadAlloc
The effect of the attribute is that
1. These functions get put into their own section, .text.unlikely,
and will be optimized for size, not speed.
2. Conditions that lead to one of these functions are automatically
marked as unlikely (something we have done manually in the past)
3. (anecdotal) the compiler is less likely to inline these functions
Text size effect of this change over all of QtBase: ~27KiB text size
saved, of which 11KiB in QtCore alone.
Change-Id: If308d4a4b9ff8f7934316c54b161a78ebe3f4205
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Diffstat (limited to 'src/corelib/global/qcompilerdetection.h')
| -rw-r--r-- | src/corelib/global/qcompilerdetection.h | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/corelib/global/qcompilerdetection.h b/src/corelib/global/qcompilerdetection.h index 50cf0889c7..885cb96c1a 100644 --- a/src/corelib/global/qcompilerdetection.h +++ b/src/corelib/global/qcompilerdetection.h @@ -243,6 +243,7 @@ # define Q_REQUIRED_RESULT __attribute__ ((__warn_unused_result__)) # define Q_DECL_PURE_FUNCTION __attribute__((pure)) # define Q_DECL_CONST_FUNCTION __attribute__((const)) +# define Q_DECL_COLD_FUNCTION __attribute__((cold)) # if !defined(QT_MOC_CPP) # define Q_PACKED __attribute__ ((__packed__)) # ifndef __ARM_EABI__ @@ -1275,6 +1276,9 @@ #ifndef Q_DECL_CONST_FUNCTION # define Q_DECL_CONST_FUNCTION Q_DECL_PURE_FUNCTION #endif +#ifndef Q_DECL_COLD_FUNCTION +# define Q_DECL_COLD_FUNCTION +#endif #ifndef QT_MAKE_UNCHECKED_ARRAY_ITERATOR # define QT_MAKE_UNCHECKED_ARRAY_ITERATOR(x) (x) #endif |