https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114532
--- Comment #5 from Zhaohaifeng <zhaohaifeng4 at huawei dot com> --- (In reply to David Brown from comment #4) > I'm not personally particularly interested in performance on x86 systems - > my work is in embedded microcontroller programming. But I did push for > "-fno-common" to be the default in gcc because "-fcommon" greatly reduces > the risk of some kinds of errors in code. > > I've tried fiddling around a bit with different gcc targets and options on > godbolt.org : > > <https://godbolt.org/z/KqxKqeKbK> > > It's easy to see the difference between common symbols and non-common > symbols by using "-fcommon" and comparing non-initialised externally linked > objects with initialised ones (since these are never common). It seems that > for some targets (like x86-64), there is no "-fsection-anchors" support at > all. For some (like mips), you can choose it explicitly. And for some > (like ARM 32-bit and 64-bit), it is automatic when optimising. I assume > section anchors can be a gain for some targets, but not so much for others. > > So certainly "-fsection-anchors" will not be a help for x86-64, since that > target does not support section anchors. (And for targets that /do/ support > them, such as ARM, it's important not to enable -fdata-sections since that > blocks the anchors.) Does gcc implement -fsection-anchors like function in -fcommon option for x86? In general concept, gcc should has some similar feature for x86 and ARM.
