[AArch64][PAC] Lower ptrauth constants in code for MachO.

Author: ahmedbougacha

llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp

@@ -1694,16 +1694,29 @@ void AArch64AsmPrinter::LowerLOADauthptrstatic(const MachineInstr &MI) {
   //
   // Where the $auth_ptr$ symbol is the stub slot containing the signed pointer
   // to symbol.
-  assert(TM.getTargetTriple().isOSBinFormatELF() &&
-         "LOADauthptrstatic is implemented only for ELF");
-  const auto &TLOF =
-      static_cast<const AArch64_ELFTargetObjectFile &>(getObjFileLowering());
-
-  assert(GAOp.getOffset() == 0 &&
-         "non-zero offset for $auth_ptr$ stub slots is not supported");
-  const MCSymbol *GASym = TM.getSymbol(GAOp.getGlobal());
-  MCSymbol *AuthPtrStubSym =
-      TLOF.getAuthPtrSlotSymbol(TM, &MF->getMMI(), GASym, Key, Disc);
+  MCSymbol *AuthPtrStubSym;
+  if (TM.getTargetTriple().isOSBinFormatELF()) {
+    const auto &TLOF =
+        static_cast<const AArch64_ELFTargetObjectFile &>(getObjFileLowering());
+
+    assert(GAOp.getOffset() == 0 &&
+           "non-zero offset for $auth_ptr$ stub slots is not supported");
+    const MCSymbol *GASym = TM.getSymbol(GAOp.getGlobal());
+    AuthPtrStubSym =
+        TLOF.getAuthPtrSlotSymbol(TM, &MF->getMMI(), GASym, Key, Disc);
+  } else {
+    assert(TM.getTargetTriple().isOSBinFormatMachO() &&
+           "LOADauthptrstatic is implemented only for MachO/ELF");
+
+    const auto &TLOF = static_cast<const AArch64_MachoTargetObjectFile &>(
+        getObjFileLowering());
+
+    assert(GAOp.getOffset() == 0 &&
+           "non-zero offset for $auth_ptr$ stub slots is not supported");
+    const MCSymbol *GASym = TM.getSymbol(GAOp.getGlobal());
+    AuthPtrStubSym =
+        TLOF.getAuthPtrSlotSymbol(TM, &MF->getMMI(), GASym, Key, Disc);
+  }
 
   MachineOperand StubMOHi =
       MachineOperand::CreateMCSymbol(AuthPtrStubSym, AArch64II::MO_PAGE);

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -9545,8 +9545,7 @@ SDValue AArch64TargetLowering::LowerGlobalTLSAddress(SDValue Op,
 //   Load a signed pointer for symbol 'sym' from a stub slot named
 //   'sym$auth_ptr$key$disc' filled by dynamic linker during relocation
 //   resolving. This usually lowers to adrp+ldr, but also emits an entry into
-//   .data with an
-//   @AUTH relocation. See LowerLOADauthptrstatic.
+//   .data with an @AUTH relocation. See LowerLOADauthptrstatic.
 //
 // All 3 are pseudos that are expand late to longer sequences: this lets us
 // provide integrity guarantees on the to-be-signed intermediate values.
@@ -9599,8 +9598,8 @@ AArch64TargetLowering::LowerPtrAuthGlobalAddress(SDValue Op,
         "constant discriminator in ptrauth global out of range [0, 0xffff]");
 
   // Choosing between 3 lowering alternatives is target-specific.
-  if (!Subtarget->isTargetELF())
-    report_fatal_error("ptrauth global lowering is only implemented for ELF");
+  if (!Subtarget->isTargetELF() && !Subtarget->isTargetMachO())
+    report_fatal_error("ptrauth global lowering only supported on MachO/ELF");
 
   int64_t PtrOffsetC = 0;
   if (Ptr.getOpcode() == ISD::ADD) {

llvm/lib/Target/AArch64/GISel/AArch64InstructionSelector.cpp

@@ -6636,8 +6636,8 @@ bool AArch64InstructionSelector::selectPtrAuthGlobalValue(
         "constant discriminator in ptrauth global out of range [0, 0xffff]");
 
   // Choosing between 3 lowering alternatives is target-specific.
-  if (!STI.isTargetELF())
-    report_fatal_error("ptrauth global lowering is only implemented for ELF");
+  if (!STI.isTargetELF() && !STI.isTargetMachO())
+    report_fatal_error("ptrauth global lowering only supported on MachO/ELF");
 
   if (!MRI.hasOneDef(Addr))
     return false;