AArch64-Darwin: allow -mcmodel=large with (default) PIC

Darwin targets implement -mcmodel=large by forcing all global accesses to use
the GOT, instead of the ELF movz/movk sequence. That means it's compatible with
PIC so the Clang driver shouldn't reject the option.

Author: TNorthover

clang/lib/Driver/ToolChains/Clang.cpp

@@ -5882,7 +5882,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
       CM = "large";
     if (Triple.isAArch64(64)) {
       Ok = CM == "tiny" || CM == "small" || CM == "large";
-      if (CM == "large" && RelocationModel != llvm::Reloc::Static)
+      if (CM == "large" && !Triple.isOSBinFormatMachO() &&
+          RelocationModel != llvm::Reloc::Static)
         D.Diag(diag::err_drv_argument_only_allowed_with)
             << A->getAsString(Args) << "-fno-pic";
     } else if (Triple.isLoongArch()) {

clang/test/Driver/mcmodel.c

@@ -11,6 +11,7 @@
 // RUN: FileCheck --check-prefix=AIX-MCMEDIUM-OVERRIDE %s < %t.log
 // RUN: not %clang -### -c -mcmodel=lager %s 2>&1 | FileCheck --check-prefix=INVALID %s
 // RUN: %clang --target=aarch64 -### -S -mcmodel=large -fno-pic %s 2>&1 | FileCheck --check-prefix=LARGE %s
+// RUN: %clang --target=aarch64-apple-macosx -### -S -mcmodel=large %s 2>&1 | FileCheck --check-prefix=LARGE %s
 // RUN: not %clang --target=aarch64 -### -S -mcmodel=large -fpic %s 2>&1 | FileCheck --check-prefix=AARCH64-PIC-LARGE %s
 // RUN: not %clang -### -c --target=aarch64 -mcmodel=medium %s 2>&1 | FileCheck --check-prefix=ERR-MEDIUM %s
 // RUN: not %clang -### -c --target=aarch64 -mcmodel=kernel %s 2>&1 | FileCheck --check-prefix=ERR-KERNEL %s