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.
Some ObjC users declare a extern variable named OBJC_CLASS_$_Foo, then use it's
address as a Class. I.e., one could define isInstanceOfF:
BOOL isInstanceOfF(id c) {
extern void OBJC_CLASS_$_F;
return [c class] == (Class)&OBJC_CLASS_$_F;
}
This leads to asserts in clang CodeGen if there is an @implementation of F in
the same TU as an instance of this pattern, because CodeGen assumes that a
variable named OBJC_CLASS_$_* has the right type. This commit fixes the problem
by RAUWing the old (incorrectly typed) global with a new global, then removing
the old global.
rdar://45077269
Differential revision: https://reviews.llvm.org/D53154
llvm-svn: 344373
Fangrui Song