[AArch64][PAC] Error out early if missing PAuth support is needed

adjustTargetOptions() was only used by AMDGCN until
ce2258c and has no in-tree users now.
Let's add Diag argument like it was done in
aaba371.

Author: atrosinenko

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -532,6 +532,9 @@ def err_stack_tagging_requires_hardware_feature : Error<
   "'-fsanitize=memtag-stack' requires hardware support (+memtag). For Armv8 or "
   "Armv9, try compiling with -march=armv8a+memtag or -march=armv9a+memtag">;
 
+def err_pauth_cpu_feature_missing : Error<
+  "A feature is requested that needs CPU with Pointer Authentication support">;
+
 def err_cmse_pi_are_incompatible : Error<
   "cmse is not compatible with %select{RWPI|ROPI}0">;
 

clang/include/clang/Basic/PointerAuthOptions.h

@@ -234,6 +234,14 @@ struct PointerAuthOptions {
   /// Should return addresses be authenticated?
   bool ReturnAddresses = false;
 
+  /// Returns all schemas being used.
+  ///
+  /// Returns all schemas that are mentioned by this instance of
+  /// PointerAuthOptions (possibly with duplicates).
+  ///
+  /// FIXME: Handle ReturnAddresses here.
+  std::vector<PointerAuthSchema> getAllUsedSchemas() const;
+
   /// The ABI for C function pointers.
   PointerAuthSchema FunctionPointers;
 

clang/include/clang/Basic/TargetInfo.h

@@ -1262,7 +1262,8 @@ class TargetInfo : public TransferrableTargetInfo,
   virtual void adjust(DiagnosticsEngine &Diags, LangOptions &Opts);
 
   /// Adjust target options based on codegen options.
-  virtual void adjustTargetOptions(const CodeGenOptions &CGOpts,
+  virtual void adjustTargetOptions(DiagnosticsEngine &Diags,
+                                   const CodeGenOptions &CGOpts,
                                    TargetOptions &TargetOpts) const {}
 
   /// Initialize the map with the default set of target features for the

clang/lib/Basic/CMakeLists.txt

@@ -76,6 +76,7 @@ add_clang_library(clangBasic
   OpenMPKinds.cpp
   OperatorPrecedence.cpp
   ParsedAttrInfo.cpp
+  PointerAuthOptions.cpp
   ProfileList.cpp
   NoSanitizeList.cpp
   SanitizerSpecialCaseList.cpp

clang/lib/Basic/PointerAuthOptions.cpp

@@ -0,0 +1,34 @@
+//===- PointerAuthOptions.cpp -----------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/PointerAuthOptions.h"
+
+using namespace clang;
+
+std::vector<PointerAuthSchema>
+clang::PointerAuthOptions::getAllUsedSchemas() const {
+  std::vector<PointerAuthSchema> Result;
+  Result.push_back(FunctionPointers);
+  Result.push_back(BlockInvocationFunctionPointers);
+  Result.push_back(BlockHelperFunctionPointers);
+  Result.push_back(BlockByrefHelperFunctionPointers);
+  Result.push_back(BlockDescriptorPointers);
+  Result.push_back(ObjCMethodListFunctionPointers);
+  Result.push_back(ObjCMethodListPointer);
+  Result.push_back(CXXVTablePointers);
+  Result.push_back(CXXTypeInfoVTablePointer);
+  Result.push_back(CXXVTTVTablePointers);
+  Result.push_back(CXXVirtualFunctionPointers);
+  Result.push_back(CXXVirtualVariadicFunctionPointers);
+  Result.push_back(CXXMemberFunctionPointers);
+  Result.push_back(ObjCIsaPointers);
+  Result.push_back(ObjCSuperPointers);
+  Result.push_back(InitFiniPointers);
+  assert(sizeof(Result[0]) * Result.size() + 4 == sizeof(PointerAuthOptions));
+  return Result;
+}

clang/lib/Basic/Targets/AArch64.cpp

@@ -11,7 +11,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "AArch64.h"
+#include "clang/Basic/DiagnosticDriver.h"
 #include "clang/Basic/LangOptions.h"
+#include "clang/Basic/PointerAuthOptions.h"
 #include "clang/Basic/TargetBuiltins.h"
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/APSInt.h"
@@ -197,6 +199,34 @@ AArch64TargetInfo::AArch64TargetInfo(const llvm::Triple &Triple,
         Opts.EABIVersion == llvm::EABI::GNU ? "\01_mcount" : "mcount";
 }
 
+void AArch64TargetInfo::validatePAuthOptions(
+    DiagnosticsEngine &Diags, const CodeGenOptions &CGOpts) const {
+  auto NeedsHWSupport = [](const PointerAuthSchema &Schema) {
+    switch (Schema.getKind()) {
+    case PointerAuthSchema::Kind::None:
+    case PointerAuthSchema::Kind::Soft:
+      return false;
+    case PointerAuthSchema::Kind::ARM8_3:
+      return true;
+    }
+    llvm_unreachable("Unexpected authentication kind");
+  };
+
+  bool NeedsFeatPAuth = false;
+  NeedsFeatPAuth |= CGOpts.PointerAuth.ReturnAddresses;
+  for (auto Schema : CGOpts.PointerAuth.getAllUsedSchemas())
+    NeedsFeatPAuth |= NeedsHWSupport(Schema);
+
+  if (NeedsFeatPAuth && !HasPAuth)
+    Diags.Report(diag::err_pauth_cpu_feature_missing);
+}
+
+void AArch64TargetInfo::adjustTargetOptions(DiagnosticsEngine &Diags,
+                                            const CodeGenOptions &CGOpts,
+                                            TargetOptions &TargetOpts) const {
+  validatePAuthOptions(Diags, CGOpts);
+}
+
 StringRef AArch64TargetInfo::getABI() const { return ABI; }
 
 bool AArch64TargetInfo::setABI(const std::string &Name) {

clang/lib/Basic/Targets/AArch64.h

@@ -91,6 +91,12 @@ class LLVM_LIBRARY_VISIBILITY AArch64TargetInfo : public TargetInfo {
 public:
   AArch64TargetInfo(const llvm::Triple &Triple, const TargetOptions &Opts);
 
+  void validatePAuthOptions(DiagnosticsEngine &Diags,
+                            const CodeGenOptions &CGOpts) const;
+  void adjustTargetOptions(DiagnosticsEngine &Diags,
+                           const CodeGenOptions &CGOpts,
+                           TargetOptions &TargetOpts) const override;
+
   StringRef getABI() const override;
   bool setABI(const std::string &Name) override;
 

clang/lib/Frontend/CompilerInstance.cpp

@@ -152,7 +152,8 @@ bool CompilerInstance::createTarget() {
   getTarget().adjust(getDiagnostics(), getLangOpts());
 
   // Adjust target options based on codegen options.
-  getTarget().adjustTargetOptions(getCodeGenOpts(), getTargetOpts());
+  getTarget().adjustTargetOptions(getDiagnostics(), getCodeGenOpts(),
+                                  getTargetOpts());
 
   if (auto *Aux = getAuxTarget())
     getTarget().setAuxTarget(Aux);

clang/test/CodeGen/ptrauth-cpu-feature.c

@@ -0,0 +1,38 @@
+// Test that features requiring FEAT_PAuth fail early:
+// RUN: not %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -mbranch-protection=pauthabi 2>&1 | FileCheck %s --check-prefix=FAIL
+// RUN: not %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-calls              2>&1 | FileCheck %s --check-prefix=FAIL
+// RUN: not %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-returns            2>&1 | FileCheck %s --check-prefix=FAIL
+// RUN: not %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-objc-isa           2>&1 | FileCheck %s --check-prefix=FAIL
+//
+// Note: at the time of writing, the following options are gated on -fptrauth-calls:
+// -fptrauth-init-fini
+// -fptrauth-function-pointer-type-discrimination
+// -fptrauth-vtable-pointer-address-discrimination
+// -fptrauth-vtable-pointer-type-discrimination
+// -fptrauth-block-descriptor-pointers
+
+// Test that v8.2-compatible code is generated, if possible:
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -mbranch-protection=pac-ret 2>&1 | FileCheck %s --check-prefix=COMPAT
+
+// Several targets imply +pauth:
+// RUN: %clang %s -S -o - -target arm64e-apple-ios 2>&1 | FileCheck %s --check-prefix=PAUTH
+
+void ext(void);
+
+int f(void) {
+  ext();
+  return 0;
+}
+
+// FAIL: error: A feature is requested that needs CPU with Pointer Authentication support
+
+// COMPAT: f:
+// COMPAT:   hint #25
+//
+// COMPAT:   hint #29
+// COMPAT:   ret
+
+// PAUTH: f:
+// PAUTH:   paci{{[ab]}}sp
+//
+// PAUTH:   reta{{[ab]}}