[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, 23 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp b/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp
index 9c3b31935f6d..f114f1ecc0ba 100644
--- a/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp
+++ b/llvm/lib/CodeGen/MachineModuleInfoImpls.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/MC/MCSymbol.h"
 
 using namespace llvm;
@@ -41,3 +42,25 @@ MachineModuleInfoImpl::SymbolListTy MachineModuleInfoImpl::getSortedStubs(
   Map.clear();
   return List;
 }
+
+template <typename MachineModuleInfoTarget>
+static typename MachineModuleInfoTarget::AuthStubListTy getAuthGVStubListHelper(
+    DenseMap<MCSymbol *, typename MachineModuleInfoTarget::AuthStubInfo>
+        &AuthPtrStubs) {
+  typename MachineModuleInfoTarget::AuthStubListTy List(AuthPtrStubs.begin(),
+                                                        AuthPtrStubs.end());
+
+  if (!List.empty())
+    llvm::sort(List.begin(), List.end(),
+               [](const typename MachineModuleInfoTarget::AuthStubPairTy &LHS,
+                  const typename MachineModuleInfoTarget::AuthStubPairTy &RHS) {
+                 return LHS.first->getName() < RHS.first->getName();
+               });
+
+  AuthPtrStubs.clear();
+  return List;
+}
+
+MachineModuleInfoELF::AuthStubListTy MachineModuleInfoELF::getAuthGVStubList() {
+  return getAuthGVStubListHelper<MachineModuleInfoELF>(AuthPtrStubs);
+}