[clang][Interp] Implement ptrauth builtins

Author: tbaederr

clang/lib/AST/Interp/ByteCodeExprGen.cpp

@@ -3572,6 +3572,7 @@ bool ByteCodeExprGen<Emitter>::VisitBuiltinCallExpr(const CallExpr *E) {
   unsigned Builtin = E->getBuiltinCallee();
   if (Builtin == Builtin::BI__builtin___CFStringMakeConstantString ||
       Builtin == Builtin::BI__builtin___NSStringMakeConstantString ||
+      Builtin == Builtin::BI__builtin_ptrauth_sign_constant ||
       Builtin == Builtin::BI__builtin_function_start) {
     if (std::optional<unsigned> GlobalOffset = P.createGlobal(E))
       return this->emitGetPtrGlobal(*GlobalOffset, E);

clang/lib/AST/Interp/InterpBuiltin.cpp

@@ -13,6 +13,7 @@
 #include "clang/AST/RecordLayout.h"
 #include "clang/Basic/Builtins.h"
 #include "clang/Basic/TargetInfo.h"
+#include "llvm/Support/SipHash.h"
 
 namespace clang {
 namespace interp {
@@ -1100,6 +1101,18 @@ static bool interp__builtin_os_log_format_buffer_size(InterpState &S,
   return true;
 }
 
+static bool interp__builtin_ptrauth_string_discriminator(
+    InterpState &S, CodePtr OpPC, const InterpFrame *Frame,
+    const Function *Func, const CallExpr *Call) {
+  const auto &Ptr = S.Stk.peek<Pointer>();
+  assert(Ptr.getFieldDesc()->isPrimitiveArray());
+
+  StringRef R(&Ptr.deref<char>(), Ptr.getFieldDesc()->getNumElems() - 1);
+  uint64_t Result = getPointerAuthStableSipHash(R);
+  pushInteger(S, Result, Call->getType());
+  return true;
+}
+
 bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
                       const CallExpr *Call) {
   const InterpFrame *Frame = S.Current;
@@ -1424,6 +1437,11 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
       return false;
     break;
 
+  case Builtin::BI__builtin_ptrauth_string_discriminator:
+    if (!interp__builtin_ptrauth_string_discriminator(S, OpPC, Frame, F, Call))
+      return false;
+    break;
+
   default:
     S.FFDiag(S.Current->getLocation(OpPC),
              diag::note_invalid_subexpr_in_const_expr)

clang/test/CodeGen/ptrauth-intrinsics.c

@@ -1,5 +1,8 @@
 // RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-intrinsics -emit-llvm %s  -o - | FileCheck %s
 // RUN: %clang_cc1 -triple aarch64-elf     -fptrauth-intrinsics -emit-llvm %s  -o - | FileCheck %s
+//
+// RUN: %clang_cc1 -triple arm64-apple-ios -fptrauth-intrinsics -emit-llvm %s  -o - -fexperimental-new-constant-interpreter | FileCheck %s
+// RUN: %clang_cc1 -triple aarch64-elf     -fptrauth-intrinsics -emit-llvm %s  -o - -fexperimental-new-constant-interpreter | FileCheck %s
 
 void (*fnptr)(void);
 long int_discriminator;