[AArch64][MachO] Support ptrauth ABI version.

This introduces additional meaning to some of the high bits in the
mach-o header "flags" byte of the cpusubtype field.  Quoting:

  // arm64 reserves bits in the high byte for subtype-specific flags.
  // On arm64e, the 6 low bits represent the ptrauth ABI version.
  CPU_SUBTYPE_ARM64E_PTRAUTH_MASK = 0x3f000000,
  // On arm64e, the top bit tells whether the Mach-O is versioned.
  CPU_SUBTYPE_ARM64E_VERSIONED_PTRAUTH_ABI_MASK = 0x80000000,
  // On arm64e, the 2nd high bit tells whether the Mach-O is using kernel ABI.
  CPU_SUBTYPE_ARM64E_KERNEL_PTRAUTH_ABI_MASK = 0x40000000

rdar://110506296
(cherry picked from commit 49328b6)

Author: ahmedbougacha

clang/include/clang/Basic/LangOptions.def

@@ -163,6 +163,10 @@ LANGOPT(PointerAuthReturns, 1, 0, "return pointer authentication")
 LANGOPT(PointerAuthIndirectGotos, 1, 0, "indirect gotos pointer authentication")
 LANGOPT(PointerAuthAuthTraps, 1, 0, "pointer authentication failure traps")
 LANGOPT(SoftPointerAuth   , 1, 0, "software emulation of pointer authentication")
+VALUE_LANGOPT(PointerAuthABIVersion, 32, 0, "pointer authentication ABI version")
+LANGOPT(PointerAuthKernelABIVersion, 1, 0, "controls whether the pointer auth abi version represents a kernel ABI")
+LANGOPT(PointerAuthABIVersionEncoded, 1, 0, "controls whether the pointer auth abi version should be encoded in the IR")
+
 LANGOPT(Unstable          , 1, 0, "Enable unstable and experimental features")
 LANGOPT(ExperimentalLibrary, 1, 0, "enable unstable and experimental library features")
 

clang/include/clang/Driver/Options.td

@@ -3150,6 +3150,20 @@ let Group = f_Group in {
   def fno_ptrauth_soft : Flag<["-"], "fno-ptrauth-soft">;
 }
 
+let Group = f_Group in {
+  def fptrauth_abi_version_EQ : Joined<["-"], "fptrauth-abi-version=">,
+    Flags<[CC1Option, CC1AsOption]>,
+    HelpText<"Pointer Authentication ABI version">;
+  def fno_ptrauth_abi_version : Flag<["-"], "fno-ptrauth-abi-version">,
+    HelpText<"Disable Pointer Authentication ABI versioning">;
+
+  def fptrauth_kernel_abi_version : Flag<["-"], "fptrauth-kernel-abi-version">,
+    Flags<[CC1Option, CC1AsOption]>,
+    HelpText<"Enable Pointer Authentication kernel ABI version">;
+  def fno_ptrauth_kernel_abi_version : Flag<["-"], "fno-ptrauth-kernel-abi-version">,
+    HelpText<"Disable Pointer Authentication kernel ABI versioning">;
+}
+
 def fenable_matrix : Flag<["-"], "fenable-matrix">, Group<f_Group>,
     Flags<[CC1Option]>,
     HelpText<"Enable matrix data type and related builtin functions">,

clang/lib/Basic/Targets/OSTargets.cpp

@@ -34,6 +34,10 @@ void getDarwinDefines(MacroBuilder &Builder, const LangOptions &Opts,
   if (Opts.PointerAuthIntrinsics)
     Builder.defineMacro("__PTRAUTH_INTRINSICS__");
 
+  if (Opts.PointerAuthABIVersionEncoded)
+    Builder.defineMacro("__ptrauth_abi_version__",
+                        llvm::utostr(Opts.PointerAuthABIVersion));
+
   // Darwin defines __weak, __strong, and __unsafe_unretained even in C mode.
   if (!Opts.ObjC) {
     // __weak is always defined, for use in blocks and with objc pointers.

clang/lib/CodeGen/CodeGenModule.cpp

@@ -863,6 +863,11 @@ void CodeGenModule::Release() {
   if (LangOpts.HLSL)
     getHLSLRuntime().finishCodeGen();
 
+  if (LangOpts.PointerAuthABIVersionEncoded)
+    TheModule.setPtrAuthABIVersion(
+        {static_cast<int>(LangOpts.PointerAuthABIVersion),
+         static_cast<bool>(LangOpts.PointerAuthKernelABIVersion)});
+
   if (uint32_t PLevel = Context.getLangOpts().PICLevel) {
     assert(PLevel < 3 && "Invalid PIC Level");
     getModule().setPICLevel(static_cast<llvm::PICLevel::Level>(PLevel));

clang/lib/Driver/ToolChains/Clang.cpp

@@ -8106,6 +8106,46 @@ void ClangAs::AddRISCVTargetArgs(const ArgList &Args,
   CmdArgs.push_back(ABIName.data());
 }
 
+void ClangAs::AddAArch64TargetArgs(const ArgList &Args,
+                                   ArgStringList &CmdArgs) const {
+  const llvm::Triple &Triple = getToolChain().getTriple();
+
+  // In the assembler, arm64e support mostly consists of setting an ABI version.
+  // It also enables various preprocessor macros, but that's done before -cc1as.
+  if (Triple.isArm64e()) {
+    // The ptrauth ABI version is 0 by default, but can be overridden.
+    static const constexpr unsigned DefaultPtrauthABIVersion = 0;
+
+    unsigned PtrAuthABIVersion = DefaultPtrauthABIVersion;
+    const Arg *A = Args.getLastArg(options::OPT_fptrauth_abi_version_EQ,
+                                   options::OPT_fno_ptrauth_abi_version);
+    bool HasVersionArg =
+        A && A->getOption().matches(options::OPT_fptrauth_abi_version_EQ);
+    if (HasVersionArg) {
+      unsigned PtrAuthABIVersionArg;
+      if (StringRef(A->getValue()).getAsInteger(10, PtrAuthABIVersionArg))
+        getToolChain().getDriver().Diag(diag::err_drv_invalid_value)
+            << A->getAsString(Args) << A->getValue();
+      else
+        PtrAuthABIVersion = PtrAuthABIVersionArg;
+    }
+
+    // Pass the ABI version to -cc1, regardless of its value, if the user asked
+    // for it or if the user didn't explicitly disable it.
+    if (HasVersionArg || !Args.hasArg(options::OPT_fno_ptrauth_abi_version)) {
+      CmdArgs.push_back(Args.MakeArgString("-fptrauth-abi-version=" +
+                                           llvm::utostr(PtrAuthABIVersion)));
+
+      // -f(no-)ptrauth-kernel-abi-version can override -mkernel and
+      // -fapple-kext
+      if (Args.hasArg(options::OPT_fptrauth_kernel_abi_version,
+                      options::OPT_mkernel, options::OPT_fapple_kext) &&
+          !Args.hasArg(options::OPT_fno_ptrauth_kernel_abi_version))
+        CmdArgs.push_back("-fptrauth-kernel-abi-version");
+    }
+  }
+}
+
 void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
                            const InputInfo &Output, const InputInfoList &Inputs,
                            const ArgList &Args,
@@ -8296,6 +8336,7 @@ void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
       CmdArgs.push_back("-mllvm");
       CmdArgs.push_back("-aarch64-mark-bti-property");
     }
+    AddAArch64TargetArgs(Args, CmdArgs);
     break;
 
   case llvm::Triple::riscv32:

clang/lib/Driver/ToolChains/Clang.h

@@ -137,6 +137,8 @@ class LLVM_LIBRARY_VISIBILITY ClangAs : public Tool {
                         llvm::opt::ArgStringList &CmdArgs) const;
   void AddRISCVTargetArgs(const llvm::opt::ArgList &Args,
                           llvm::opt::ArgStringList &CmdArgs) const;
+  void AddAArch64TargetArgs(const llvm::opt::ArgList &Args,
+                            llvm::opt::ArgStringList &CmdArgs) const;
   bool hasGoodDiagnostics() const override { return true; }
   bool hasIntegratedAssembler() const override { return false; }
   bool hasIntegratedCPP() const override { return false; }

clang/lib/Driver/ToolChains/Darwin.cpp

@@ -1244,6 +1244,38 @@ void DarwinClang::addClangTargetOptions(
   // On arm64e, enable pointer authentication (for the return address and
   // indirect calls), as well as usage of the intrinsics.
   if (getArchName() == "arm64e") {
+    // The ptrauth ABI version is 0 by default, but can be overridden.
+    static const constexpr unsigned DefaultPtrauthABIVersion = 0;
+
+    unsigned PtrAuthABIVersion = DefaultPtrauthABIVersion;
+    const Arg *A = DriverArgs.getLastArg(options::OPT_fptrauth_abi_version_EQ,
+                                         options::OPT_fno_ptrauth_abi_version);
+    bool HasVersionArg =
+        A && A->getOption().matches(options::OPT_fptrauth_abi_version_EQ);
+    if (HasVersionArg) {
+      unsigned PtrAuthABIVersionArg;
+      if (StringRef(A->getValue()).getAsInteger(10, PtrAuthABIVersionArg))
+        getDriver().Diag(diag::err_drv_invalid_value)
+          << A->getAsString(DriverArgs) << A->getValue();
+      else
+        PtrAuthABIVersion = PtrAuthABIVersionArg;
+    }
+
+    // Pass the ABI version to -cc1, regardless of its value, if the user asked
+    // for it or if the user didn't explicitly disable it.
+    if (HasVersionArg ||
+        !DriverArgs.hasArg(options::OPT_fno_ptrauth_abi_version)) {
+      CC1Args.push_back(DriverArgs.MakeArgString(
+          "-fptrauth-abi-version=" + llvm::utostr(PtrAuthABIVersion)));
+
+      // -f(no-)ptrauth-kernel-abi-version can override -mkernel and
+      // -fapple-kext
+      if (DriverArgs.hasArg(options::OPT_fptrauth_kernel_abi_version,
+                            options::OPT_mkernel, options::OPT_fapple_kext) &&
+          !DriverArgs.hasArg(options::OPT_fno_ptrauth_kernel_abi_version))
+        CC1Args.push_back("-fptrauth-kernel-abi-version");
+    }
+
     if (!DriverArgs.hasArg(options::OPT_fptrauth_returns,
                            options::OPT_fno_ptrauth_returns))
       CC1Args.push_back("-fptrauth-returns");

clang/lib/Frontend/CompilerInvocation.cpp

@@ -3655,15 +3655,30 @@ static void GeneratePointerAuthArgs(LangOptions &Opts,
     GenerateArg(Args, OPT_fptrauth_auth_traps, SA);
   if (Opts.SoftPointerAuth)
     GenerateArg(Args, OPT_fptrauth_soft, SA);
+
+  if (Opts.PointerAuthABIVersionEncoded) {
+    GenerateArg(Args, OPT_fptrauth_abi_version_EQ,
+                Twine(Opts.PointerAuthABIVersion), SA);
+    if (Opts.PointerAuthKernelABIVersion)
+      GenerateArg(Args, OPT_fptrauth_kernel_abi_version, SA);
+  }
 }
 
-static void ParsePointerAuthArgs(LangOptions &Opts, ArgList &Args) {
+static void ParsePointerAuthArgs(LangOptions &Opts, ArgList &Args,
+                                 DiagnosticsEngine &Diags) {
   Opts.PointerAuthIntrinsics = Args.hasArg(OPT_fptrauth_intrinsics);
   Opts.PointerAuthCalls = Args.hasArg(OPT_fptrauth_calls);
   Opts.PointerAuthReturns = Args.hasArg(OPT_fptrauth_returns);
   Opts.PointerAuthIndirectGotos = Args.hasArg(OPT_fptrauth_indirect_gotos);
   Opts.PointerAuthAuthTraps = Args.hasArg(OPT_fptrauth_auth_traps);
   Opts.SoftPointerAuth = Args.hasArg(OPT_fptrauth_soft);
+
+  Opts.PointerAuthABIVersionEncoded =
+      Args.hasArg(OPT_fptrauth_abi_version_EQ) ||
+      Args.hasArg(OPT_fptrauth_kernel_abi_version);
+  Opts.PointerAuthABIVersion =
+      getLastArgIntValue(Args, OPT_fptrauth_abi_version_EQ, 0, Diags);
+  Opts.PointerAuthKernelABIVersion = Args.hasArg(OPT_fptrauth_kernel_abi_version);
 }
 
 /// Check if input file kind and language standard are compatible.
@@ -4958,7 +4973,7 @@ bool CompilerInvocation::CreateFromArgsImpl(
   ParseHeaderSearchArgs(Res.getHeaderSearchOpts(), Args, Diags,
                         Res.getFileSystemOpts().WorkingDir);
   ParseAPINotesArgs(Res.getAPINotesOpts(), Args, Diags);
-  ParsePointerAuthArgs(LangOpts, Args);
+  ParsePointerAuthArgs(LangOpts, Args, Diags);
 
   ParseLangArgs(LangOpts, Args, DashX, T, Res.getPreprocessorOpts().Includes,
                 Diags);

clang/test/CodeGen/ptrauth-abi-version.c

@@ -0,0 +1,18 @@
+// RUN: %clang_cc1 %s                                                      -triple arm64e-apple-ios -disable-llvm-passes -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-NONE
+// RUN: %clang_cc1 %s                         -fptrauth-kernel-abi-version -triple arm64e-apple-ios -disable-llvm-passes -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-WITH --check-prefix=CHECK-ZEROK
+// RUN: %clang_cc1 %s -fptrauth-abi-version=0                              -triple arm64e-apple-ios -disable-llvm-passes -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-WITH --check-prefix=CHECK-ZERO
+// RUN: %clang_cc1 %s -fptrauth-abi-version=0 -fptrauth-kernel-abi-version -triple arm64e-apple-ios -disable-llvm-passes -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-WITH --check-prefix=CHECK-ZEROK
+// RUN: %clang_cc1 %s -fptrauth-abi-version=5                              -triple arm64e-apple-ios -disable-llvm-passes -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-WITH --check-prefix=CHECK-FIVE
+// RUN: %clang_cc1 %s -fptrauth-abi-version=5 -fptrauth-kernel-abi-version -triple arm64e-apple-ios -disable-llvm-passes -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-WITH --check-prefix=CHECK-FIVEK
+
+int f(void) {
+  return 0;
+}
+// CHECK-NONE-NOT: ptrauth.abi-version
+// CHECK-WITH:  !llvm.module.flags = !{{{.*}} ![[ABI_VERSION_REF:[0-9]+]]}
+// CHECK-WITH:  ![[ABI_VERSION_REF]] = !{i32 6, !"ptrauth.abi-version", ![[ABI_VERSION_VAR:[0-9]+]]}
+// CHECK-WITH:  ![[ABI_VERSION_VAR]] = !{![[ABI_VERSION_VAL:[0-9]+]]}
+// CHECK-ZERO:  ![[ABI_VERSION_VAL]] = !{i32 0, i1 false}
+// CHECK-ZEROK: ![[ABI_VERSION_VAL]] = !{i32 0, i1 true}
+// CHECK-FIVE:  ![[ABI_VERSION_VAL]] = !{i32 5, i1 false}
+// CHECK-FIVEK: ![[ABI_VERSION_VAL]] = !{i32 5, i1 true}

clang/test/Driver/arch-arm64e-abi-versioning-defaults.c

@@ -0,0 +1,16 @@
+// Check the ABI version support defaults.
+
+// RUN: %clang                                                      -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix NOKERNELABIVERSION
+// RUN: %clang                         -mkernel                     -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix KERNELABIVERSION
+// RUN: %clang                         -fapple-kext                 -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix KERNELABIVERSION
+//
+// RUN: %clang -fno-ptrauth-kernel-abi-version -mkernel                        -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix NOKERNELABIVERSION
+// RUN: %clang -mkernel                        -fno-ptrauth-kernel-abi-version -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix NOKERNELABIVERSION
+// RUN: %clang -fno-ptrauth-kernel-abi-version -fapple-kext                    -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix NOKERNELABIVERSION
+// RUN: %clang -fapple-kext                    -fno-ptrauth-kernel-abi-version -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix NOKERNELABIVERSION
+// RUN: %clang -fno-ptrauth-kernel-abi-version -fptrauth-kernel-abi-version    -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix NOKERNELABIVERSION
+// RUN: %clang -fptrauth-kernel-abi-version    -fno-ptrauth-kernel-abi-version -arch arm64e -c %s -### 2>&1 | FileCheck %s --check-prefix ABIVERSION-DEFAULT --check-prefix NOKERNELABIVERSION
+//
+// ABIVERSION-DEFAULT: "-fptrauth-abi-version=0"
+// KERNELABIVERSION: "-fptrauth-kernel-abi-version"
+// NOKERNELABIVERSION-NOT: fptrauth-kernel-abi-version