Make type discrimination of 128-bit types optional

asl · asl · commit d511d026dd92 · 2025-06-02T00:21:11.000-07:00
diff --git a/clang/include/clang/Basic/Features.def b/clang/include/clang/Basic/Features.def
@@ -119,6 +119,7 @@ FEATURE(ptrauth_indirect_gotos, LangOpts.PointerAuthIndirectGotos)
 FEATURE(ptrauth_init_fini, LangOpts.PointerAuthInitFini)
 FEATURE(ptrauth_init_fini_address_discrimination, LangOpts.PointerAuthInitFiniAddressDiscrimination)
 FEATURE(ptrauth_elf_got, LangOpts.PointerAuthELFGOT)
+FEATURE(ptrauth_function_pointer_type_discrimination_128, LangOpts.PointerAuthFunctionTypeDiscrimination128)
 EXTENSION(swiftcc,
   PP.getTargetInfo().checkCallingConvention(CC_Swift) ==
   clang::TargetInfo::CCCR_OK)
diff --git a/clang/include/clang/Basic/LangOptions.def b/clang/include/clang/Basic/LangOptions.def
@@ -172,6 +172,8 @@ LANGOPT(PointerAuthVTPtrTypeDiscrimination, 1, 0, "incorporate type discriminati
 LANGOPT(PointerAuthTypeInfoVTPtrDiscrimination, 1, 0, "incorporate type and address discrimination in authenticated vtable pointers for std::type_info")
 BENIGN_LANGOPT(PointerAuthFunctionTypeDiscrimination, 1, 0,
                "Use type discrimination when signing function pointers")
+LANGOPT(PointerAuthFunctionTypeDiscrimination128, 1, 1,
+        "Use different discriminators for __int128_t / __uint128_t / _BitInt(n) compared to other integer types when computing function pointer type discriminator")
 LANGOPT(PointerAuthInitFini, 1, 0, "sign function pointers in init/fini arrays")
 LANGOPT(PointerAuthInitFiniAddressDiscrimination, 1, 0,
         "incorporate address discrimination in authenticated function pointers in init/fini arrays")
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
@@ -4451,6 +4451,8 @@ defm ptrauth_init_fini_address_discrimination : OptInCC1FFlag<"ptrauth-init-fini
   "Enable address discrimination of function pointers in init/fini arrays">;
 defm ptrauth_elf_got : OptInCC1FFlag<"ptrauth-elf-got", "Enable authentication of pointers from GOT (ELF only)">;
 defm aarch64_jump_table_hardening: OptInCC1FFlag<"aarch64-jump-table-hardening", "Use hardened lowering for jump-table dispatch">;
+defm ptrauth_disable_128bit_type_discrimination : OptInCC1FFlag<"ptrauth-disable-128bit-type-discrimination",
+  "Do not use different discriminators for __int128_t / __uint128_t / _BitInt(n) compared to other integer types when computing function pointer type discriminator">;
 }
 
 def fenable_matrix : Flag<["-"], "fenable-matrix">, Group<f_Group>,
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
@@ -3399,23 +3399,32 @@ static void encodeTypeForFunctionPointerAuth(const ASTContext &Ctx,
     OS << "?";
     return;
 
-  case Type::BitInt: {
-    const auto *BtTy = T->castAs<BitIntType>();
-    OS << "D" << (BtTy->isUnsigned() ? "U" : "B") << BtTy->getNumBits() << "_";
+  case Type::BitInt:
+    if (Ctx.getLangOpts().PointerAuthFunctionTypeDiscrimination128) {
+      const auto *BtTy = T->castAs<BitIntType>();
+      OS << "D" << (BtTy->isUnsigned() ? "U" : "B") << BtTy->getNumBits()
+         << "_";
+    } else
+      OS << "?";
     return;
-  }
 
   case Type::Builtin: {
     const auto *BTy = T->castAs<BuiltinType>();
     const auto Kind = BTy->getKind();
     switch (Kind) {
 #define SIGNED_TYPE(Id, SingletonId)                                           \
   case BuiltinType::Id:                                                        \
-    OS << (Kind == BuiltinType::Int128 ? "n" : "i");                           \
+    OS << (Kind == BuiltinType::Int128 &&                                      \
+                   Ctx.getLangOpts().PointerAuthFunctionTypeDiscrimination128  \
+               ? "n"                                                           \
+               : "i");                                                         \
     return;
 #define UNSIGNED_TYPE(Id, SingletonId)                                         \
   case BuiltinType::Id:                                                        \
-    OS << (Kind == BuiltinType::UInt128 ? "o" : "i");                          \
+    OS << (Kind == BuiltinType::UInt128 &&                                     \
+                   Ctx.getLangOpts().PointerAuthFunctionTypeDiscrimination128  \
+               ? "o"                                                           \
+               : "i");                                                         \
     return;
 #define PLACEHOLDER_TYPE(Id, SingletonId) case BuiltinType::Id:
 #define BUILTIN_TYPE(Id, SingletonId)
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -1883,6 +1883,9 @@ void Clang::AddAArch64TargetArgs(const ArgList &Args,
   Args.addOptInFlag(
       CmdArgs, options::OPT_fptrauth_function_pointer_type_discrimination,
       options::OPT_fno_ptrauth_function_pointer_type_discrimination);
+  Args.addOptInFlag(
+      CmdArgs, options::OPT_fptrauth_disable_128bit_type_discrimination,
+      options::OPT_fno_ptrauth_disable_128bit_type_discrimination);
 
   Args.addOptInFlag(CmdArgs, options::OPT_fptrauth_indirect_gotos,
                     options::OPT_fno_ptrauth_indirect_gotos);
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -3544,6 +3544,8 @@ static void GeneratePointerAuthArgs(const LangOptions &Opts,
     GenerateArg(Consumer, OPT_fptrauth_type_info_vtable_pointer_discrimination);
   if (Opts.PointerAuthFunctionTypeDiscrimination)
     GenerateArg(Consumer, OPT_fptrauth_function_pointer_type_discrimination);
+  if (!Opts.PointerAuthFunctionTypeDiscrimination128)
+    GenerateArg(Consumer, OPT_fptrauth_disable_128bit_type_discrimination);
   if (Opts.PointerAuthInitFini)
     GenerateArg(Consumer, OPT_fptrauth_init_fini);
   if (Opts.PointerAuthInitFiniAddressDiscrimination)
@@ -3569,6 +3571,8 @@ static void ParsePointerAuthArgs(LangOptions &Opts, ArgList &Args,
       Args.hasArg(OPT_fptrauth_type_info_vtable_pointer_discrimination);
   Opts.PointerAuthFunctionTypeDiscrimination =
       Args.hasArg(OPT_fptrauth_function_pointer_type_discrimination);
+  Opts.PointerAuthFunctionTypeDiscrimination128 =
+      !Args.hasArg(OPT_fptrauth_disable_128bit_type_discrimination);
   Opts.PointerAuthInitFini = Args.hasArg(OPT_fptrauth_init_fini);
   Opts.PointerAuthInitFiniAddressDiscrimination =
       Args.hasArg(OPT_fptrauth_init_fini_address_discrimination);
diff --git a/clang/test/CodeGen/ptrauth-function-type-discriminator.c b/clang/test/CodeGen/ptrauth-function-type-discriminator.c
@@ -1,18 +1,20 @@
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics \
-// RUN:   -disable-llvm-passes -emit-llvm %s       -o- | FileCheck --check-prefixes=CHECK,CHECKC %s
+// RUN:   -disable-llvm-passes -emit-llvm %s       -o- | FileCheck --check-prefixes=CHECK,CHECKC,CHECK128 %s
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics \
-// RUN:   -disable-llvm-passes -emit-llvm -xc++ %s -o- | FileCheck --check-prefix=CHECK %s
+// RUN:   -disable-llvm-passes -emit-llvm -xc++ %s -o- | FileCheck --check-prefixes=CHECK,CHECK128 %s
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple arm64-apple-ios    -fptrauth-calls -fptrauth-intrinsics -emit-pch %s -o %t.ast
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple arm64-apple-ios    -fptrauth-calls -fptrauth-intrinsics \
-// RUN:   -emit-llvm -x ast -o - %t.ast | FileCheck --check-prefixes=CHECK,CHECKC %s
+// RUN:   -emit-llvm -x ast -o - %t.ast | FileCheck --check-prefixes=CHECK,CHECKC,CHECK128 %s
+// RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple arm64e-apple-ios13 -fptrauth-calls -fptrauth-intrinsics \
+// RUN:   -fptrauth-disable-128bit-type-discrimination -disable-llvm-passes -emit-llvm %s       -o- | FileCheck --check-prefixes=CHECK,CHECKC,CHECKNO128 %s
 
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple aarch64-linux-gnu  -fptrauth-calls -fptrauth-intrinsics \
-// RUN:   -disable-llvm-passes -emit-llvm %s       -o- | FileCheck --check-prefixes=CHECK,CHECKC %s
+// RUN:   -disable-llvm-passes -emit-llvm %s       -o- | FileCheck --check-prefixes=CHECK,CHECKC,CHECK128 %s
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple aarch64-linux-gnu  -fptrauth-calls -fptrauth-intrinsics \
-// RUN:   -disable-llvm-passes -emit-llvm -xc++ %s -o- | FileCheck --check-prefix=CHECK %s
+// RUN:   -disable-llvm-passes -emit-llvm -xc++ %s -o- | FileCheck --check-prefixes=CHECK,CHECK128 %s
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple aarch64-linux-gnu  -fptrauth-calls -fptrauth-intrinsics -emit-pch %s -o %t.ast
 // RUN: %clang_cc1 -fptrauth-function-pointer-type-discrimination -triple aarch64-linux-gnu  -fptrauth-calls -fptrauth-intrinsics \
-// RUN:   -emit-llvm -x ast -o - %t.ast | FileCheck --check-prefixes=CHECK,CHECKC %s
+// RUN:   -emit-llvm -x ast -o - %t.ast | FileCheck --check-prefixes=CHECK,CHECKC,CHECK128 %s
 
 #ifdef __cplusplus
 extern "C" {
@@ -87,10 +89,14 @@ extern void external_function_b8(_BitInt(8));
 void (*fptr5)(int) = external_function_int;
 void (*fptr6)(char) = external_function_char;
 
-// CHECK: @fptr7 = global ptr ptrauth (ptr @external_function_i128, i32 0, i64 23141)
-// CHECK: @fptr8 = global ptr ptrauth (ptr @external_function_u128, i32 0, i64 45743)
-// CHECK: @fptr9 = global ptr ptrauth (ptr @external_function_b128, i32 0, i64 17854)
-// CHECK: @fptr10 = global ptr ptrauth (ptr @external_function_b8, i32 0, i64 26383)
+// CHECK128: @fptr7 = global ptr ptrauth (ptr @external_function_i128, i32 0, i64 23141)
+// CHECK128: @fptr8 = global ptr ptrauth (ptr @external_function_u128, i32 0, i64 45743)
+// CHECK128: @fptr9 = global ptr ptrauth (ptr @external_function_b128, i32 0, i64 17854)
+// CHECK128: @fptr10 = global ptr ptrauth (ptr @external_function_b8, i32 0, i64 26383)
+// CHECKNO128: @fptr7 = global ptr ptrauth (ptr @external_function_i128, i32 0, i64 2712)
+// CHECKNO128: @fptr8 = global ptr ptrauth (ptr @external_function_u128, i32 0, i64 2712)
+// CHECKNO128: @fptr9 = global ptr ptrauth (ptr @external_function_b128, i32 0, i64 41228)
+// CHECKNO128: @fptr10 = global ptr ptrauth (ptr @external_function_b8, i32 0, i64 41228)
 void (*fptr7)(__int128_t) = external_function_i128;
 void (*fptr8)(__uint128_t) = external_function_u128;
 void (*fptr9)(_BitInt(128)) = external_function_b128;

Original file line number	Diff line number	Diff line change
`@@ -4451,6 +4451,8 @@ defm ptrauth_init_fini_address_discrimination : OptInCC1FFlag<"ptrauth-init-fini`
`4451`	`4451`	`"Enable address discrimination of function pointers in init/fini arrays">;`
`4452`	`4452`	`defm ptrauth_elf_got : OptInCC1FFlag<"ptrauth-elf-got", "Enable authentication of pointers from GOT (ELF only)">;`
`4453`	`4453`	`defm aarch64_jump_table_hardening: OptInCC1FFlag<"aarch64-jump-table-hardening", "Use hardened lowering for jump-table dispatch">;`
	`4454`	`+defm ptrauth_disable_128bit_type_discrimination : OptInCC1FFlag<"ptrauth-disable-128bit-type-discrimination",`
	`4455`	`+ "Do not use different discriminators for __int128_t / __uint128_t / _BitInt(n) compared to other integer types when computing function pointer type discriminator">;`
`4454`	`4456`	`}`
`4455`	`4457`
`4456`	`4458`	`def fenable_matrix : Flag<["-"], "fenable-matrix">, Group<f_Group>,`