Hi Jorn,
On 17/06/2021 9:28 pm, Jorn Vernee wrote:
On Thu, 17 Jun 2021 00:23:19 GMT, David Holmes <dhol...@openjdk.org> wrote:
Jorn Vernee has updated the pull request incrementally with one additional
commit since the last revision:
Add comment about optimized entry frames only being generated on x86_64
src/hotspot/share/runtime/frame.inline.hpp line 54:
52: inline bool frame::is_first_frame() const {
53: return (is_entry_frame() && entry_frame_is_first())
54: || (is_optimized_entry_frame() && optimized_entry_frame_is_first());
Given `optimized_entry_frame_is_first` is only defined on a couple of
platforms, it is far from obvious that this call can never happen on the other
platforms. A comment explaining this would be useful.
Thanks, I've added the following comment:
```C++
inline bool frame::is_first_frame() const {
return (is_entry_frame() && entry_frame_is_first())
// optimized_entry_frame_is_first is currently only implemented on
x86_64.
// This is okay since optimized entry frames are only generated on x86_64
// as well (see ProgrammableUpcallHandler::generate_optimized_upcall_stub
// in universalUpcallHandler_x86_64.cpp), so is_optimized_entry_frame
will
// always return false on platforms where optimized_entry_frame_is_first
// is not implemented.
|| (is_optimized_entry_frame() && optimized_entry_frame_is_first());
}
Now that you have explained it I think a much simpler comment will
suffice :)
return (is_entry_frame() && entry_frame_is_first()) ||
// Optimized entry frames are only present on certain platforms
(is_optimized_entry_frame() && optimized_entry_frame_is_first());
Cheers,
David
-------------
PR: https://git.openjdk.java.net/jdk17/pull/76
