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.
When we are calling `__builtin_constant_p` with ObjC objects of
different classes, we hit the assertion
> Assertion failed: (isa<X>(Val) && "cast<Ty>() argument of incompatible type!"), function cast, file include/llvm/Support/Casting.h, line 254.
It happens because LLVM types for `ObjCInterfaceType` are opaque and
have no name (see `CodeGenTypes::ConvertType`). As the result, for
different ObjC classes we have different `is_constant` intrinsics with
the same name `llvm.is.constant.p0s_s`. When we try to reuse an
intrinsic with the same name, we fail because of type mismatch.
Fix by bitcasting `ObjCObjectPointerType` to `id` prior to passing as an
argument to `__builtin_constant_p`. This results in using intrinsic
`llvm.is.constant.p0i8` and correct types.
rdar://problem/47499250
Reviewers: rjmccall, ahatanak, void
Reviewed By: void, ahatanak
Subscribers: ddunbar, jkorous, hans, dexonsmith, cfe-commits
Differential Revision: https://reviews.llvm.org/D57427
llvm-svn: 353577
Fangrui Song