[PAC][AArch64] Lower ptrauth constants in code (#94241)

Depends on #94240.

Define the following pseudos for lowering ptrauth constants in code:

- non-`extern_weak`:
  - no GOT load needed: `MOVaddrPAC` - similar to `MOVaddr`, with added
    PAC;
  - GOT load needed: `LOADgotPAC` - similar to `LOADgot`, with added PAC;
- `extern_weak`: `LOADauthptrstatic` - similar to `LOADgot`, but use a
  special stub slot named `sym$auth_ptr$key$disc` filled by dynamic linker
  during relocation resolving instead of a GOT slot.

---------

Co-authored-by: Ahmed Bougacha <ahmed@bougacha.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
index 37aa4e0..06a6c1f9 100644
--- a/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/MachineIRBuilder.cpp
@@ -397,6 +397,19 @@ MachineInstrBuilder MachineIRBuilder::buildFConstant(const DstOp &Res,
   return buildFConstant(Res, *CFP);
 }
 
+MachineInstrBuilder
+MachineIRBuilder::buildConstantPtrAuth(const DstOp &Res,
+                                       const ConstantPtrAuth *CPA,
+                                       Register Addr, Register AddrDisc) {
+  auto MIB = buildInstr(TargetOpcode::G_PTRAUTH_GLOBAL_VALUE);
+  Res.addDefToMIB(*getMRI(), MIB);
+  MIB.addUse(Addr);
+  MIB.addImm(CPA->getKey()->getZExtValue());
+  MIB.addUse(AddrDisc);
+  MIB.addImm(CPA->getDiscriminator()->getZExtValue());
+  return MIB;
+}
+
 MachineInstrBuilder MachineIRBuilder::buildBrCond(const SrcOp &Tst,
                                                   MachineBasicBlock &Dest) {
   assert(Tst.getLLTTy(*getMRI()).isScalar() && "invalid operand type");