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Diffstat (limited to 'ld/ld.texinfo')
| -rw-r--r-- | ld/ld.texinfo | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/ld/ld.texinfo b/ld/ld.texinfo index 987816f..172c1dd 100644 --- a/ld/ld.texinfo +++ b/ld/ld.texinfo @@ -7600,6 +7600,21 @@ barrier in the call stub, or use LD_BIND_NOW=1. By default, @code{ld} looks for calls to commonly used functions that create threads, and if seen, adds the necessary barriers. Use these options to change the default behaviour. + +@cindex PowerPC64 ELFv2 PLT localentry optimization +@kindex --plt-localentry +@kindex --no-plt-localentry +@item --plt-localentry +@itemx --no-localentry +ELFv2 functions with localentry:0 are those with a single entry point, +ie. global entry == local entry, and that have no requirement on r2 +(the TOC/GOT pointer) or r12, and guarantee r2 is unchanged on return. +Such an external function can be called via the PLT without saving r2 +or restoring it on return, avoiding a common load-hit-store for small +functions. The optimization is attractive, with up to 40% reduction +in execution time for a small function, but can result in symbol +interposition failures. Use with care. @option{--no-plt-localentry} +is the default. @end table @ifclear GENERIC |