[clang][ObjC][PAC] Add ptrauth protections to objective-c (#147899)

This PR introduces the use of pointer authentication to objective-c[++].

This includes:

* __ptrauth qualifier support for ivars
* protection of isa and super fields
* protection of SEL typed ivars
* protection of class_ro_t data
* protection of methodlist pointers and content

1 files changed, 19 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index f3ddf7b..1aba841 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -853,9 +853,24 @@ llvm::Value *CodeGenFunction::EmitBlockLiteral(const CGBlockInfo &blockInfo) {
       offset += size;
       index++;
     };
+    auto addSignedHeaderField =
+        [&](llvm::Value *Value, const PointerAuthSchema &Schema,
+            GlobalDecl Decl, QualType Type, CharUnits Size, const Twine &Name) {
+          auto StorageAddress = projectField(index, Name);
+          if (Schema) {
+            auto AuthInfo = EmitPointerAuthInfo(
+                Schema, StorageAddress.emitRawPointer(*this), Decl, Type);
+            Value = EmitPointerAuthSign(AuthInfo, Value);
+          }
+          Builder.CreateStore(Value, StorageAddress);
+          offset += Size;
+          index++;
+        };
 
     if (!IsOpenCL) {
-      addHeaderField(isa, getPointerSize(), "block.isa");
+      addSignedHeaderField(
+          isa, CGM.getCodeGenOpts().PointerAuth.ObjCIsaPointers, GlobalDecl(),
+          QualType(), getPointerSize(), "block.isa");
       addHeaderField(llvm::ConstantInt::get(IntTy, flags.getBitMask()),
                      getIntSize(), "block.flags");
       addHeaderField(llvm::ConstantInt::get(IntTy, 0), getIntSize(),
@@ -1285,7 +1300,9 @@ static llvm::Constant *buildGlobalBlock(CodeGenModule &CGM,
     if (IsWindows)
       fields.addNullPointer(CGM.Int8PtrPtrTy);
     else
-      fields.add(CGM.getNSConcreteGlobalBlock());
+      fields.addSignedPointer(CGM.getNSConcreteGlobalBlock(),
+                              CGM.getCodeGenOpts().PointerAuth.ObjCIsaPointers,
+                              GlobalDecl(), QualType());
 
     // __flags
     BlockFlags flags = BLOCK_IS_GLOBAL;