It would be beneficial to allow not_tail_called attribute to be applied to
virtual functions. I don't see any drawback of allowing this.
Differential Revision: https://reviews.llvm.org/D96832
For a definition (of most linkage types), dso_local is set for ELF -fno-pic/-fpie
and COFF, but not for Mach-O. This nuance causes unneeded binary format differences.
This patch replaces (function) `define ` with `define{{.*}} `,
(variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} `
if there is an explicit linkage.
* Clang will set dso_local for Mach-O, which is currently implied by TargetMachine.cpp. This will make COFF/Mach-O and executable ELF similar.
* Eventually I hope we can make dso_local the textual LLVM IR default (write explicit "dso_preemptable" when applicable) and -fpic ELF will be similar to everything else. This patch helps move toward that goal.
This attribute is used to prevent tail-call optimizations to the marked
function. For example, in the following piece of code, foo1 will not be
tail-call optimized:
int __attribute__((not_tail_called)) foo1(int);
int foo2(int a) {
return foo1(a); // Tail-call optimization is not performed.
}
The attribute has effect only on statically bound calls. It has no
effect on indirect calls. Also, virtual functions and objective-c
methods cannot be marked as 'not_tail_called'.
rdar://problem/22667622
Differential Revision: http://reviews.llvm.org/D12922
llvm-svn: 252369
Zequan Wu