Since some profiling tools, such as gprof, ftrace, and uftrace, use
-pg option to generate a mcount function call at the entry of each
function. Function invocation can be detected by this hook function.
But mcount insertion is done before function inlining phase in clang,
sometime a function that already has a mcount call can be inlined in the
middle of another function.
This patch adds an attribute "counting-function" to each function
rather than emitting the mcount call directly in frontend so that this
attribute can be processed in backend. Then the mcount calls can be
properly inserted in backend after all the other optimizations are
completed.
Link: https://llvm.org/bugs/show_bug.cgi?id=28660
Reviewers: hans, rjmccall, hfinkel, rengolin, compnerd
Subscribers: shenhan, cfe-commits
Differential Revision: https://reviews.llvm.org/D22666
llvm-svn: 280355
The GNU profiling support indicates that the interface is `_mcount` rather than
`mcount`. Conditionalise the behaviour according to the `-meabi gnu` flag.
Resolves PR27311
llvm-svn: 266039
It seems that there was a miscommunication between Renato and I, and the
original behaviour of AArch64 was to be preserved and not to mirror the new
behaviour. Restore the original behaviour for AArch64. Addresses post-commit
review comments from Renato Golin.
llvm-svn: 265899
This adds support to optionally support using `__gnu_mcount_nc` as the mcount
interface rather than `mcount` for Linux and EABI. The other targets do not
provide an implementation for `__gnu_mcount_nc`. This can be activated via the
`-meabi gnu` flag.
Resolves PR23969.
llvm-svn: 265888
Eric Christopher