Address comments (more to be done)

Author: atrosinenko

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -533,7 +533,10 @@ def err_stack_tagging_requires_hardware_feature : Error<
   "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">;
+  "neither FEAT_PAUTH nor -fptrauth-soft is enabled. Most of PAuth features are unavailable">;
+
+def warn_pauth_feature_ignored : Warning<
+  "%0 is ignored because %1 is not specified">;
 
 def err_cmse_pi_are_incompatible : Error<
   "cmse is not compatible with %select{RWPI|ROPI}0">;

clang/lib/Basic/Targets/AArch64.cpp

@@ -202,19 +202,44 @@ AArch64TargetInfo::AArch64TargetInfo(const llvm::Triple &Triple,
 
 void AArch64TargetInfo::validatePAuthOptions(DiagnosticsEngine &Diags,
                                              const LangOptions &Opts) const {
-  if (Opts.SoftPointerAuth)
+  if (!Opts.PointerAuthCalls) {
+    auto IgnoredWithoutPtrAuthCalls = [&Diags](const StringRef OptString) {
+      Diags.Report(diag::warn_pauth_feature_ignored)
+          << OptString << "-fptrauth-calls";
+    };
+
+    if (Opts.PointerAuthInitFini)
+      IgnoredWithoutPtrAuthCalls("-fptrauth-init-fini");
+    if (Opts.FunctionPointerTypeDiscrimination)
+      IgnoredWithoutPtrAuthCalls(
+          "-fptrauth-function-pointer-type-discrimination");
+    if (Opts.PointerAuthVTPtrAddressDiscrimination)
+      IgnoredWithoutPtrAuthCalls(
+          "-fptrauth-vtable-pointer-address-discrimination");
+    if (Opts.PointerAuthVTPtrTypeDiscrimination)
+      IgnoredWithoutPtrAuthCalls(
+          "-fptrauth-vtable-pointer-type-discrimination");
+    if (Opts.PointerAuthBlockDescriptorPointers)
+      IgnoredWithoutPtrAuthCalls("-fptrauth-block-descriptor-pointers");
+  }
+
+  if (HasPAuth || Opts.SoftPointerAuth)
     return;
 
   bool NeedsFeatPAuth = false;
-  // FIXME: Some ptrauth_* intrinsics can be implemented without FEAT_PAuth.
+  // FIXME: Some ptrauth_* intrinsics can be implemented by only using
+  //        HINT-encoded instructions, thus not requiring FEAT_PAUTH.
   //        At now, checking conservatively.
   NeedsFeatPAuth |= Opts.PointerAuthIntrinsics;
   NeedsFeatPAuth |= Opts.PointerAuthCalls;
   NeedsFeatPAuth |= Opts.PointerAuthReturns;
   NeedsFeatPAuth |= Opts.getPointerAuthObjcIsaAuthentication() !=
                     PointerAuthenticationMode::None;
 
-  if (NeedsFeatPAuth && !HasPAuth)
+  // FIXME The particular command line option is not printed in error message,
+  //       as it would misleadingly mention various -fptrauth-<something>
+  //       options instead of -mbranch-protection=pauthabi.
+  if (NeedsFeatPAuth)
     Diags.Report(diag::err_pauth_cpu_feature_missing);
 }
 

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

@@ -7,16 +7,20 @@
 // 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
 //
-// RUN:     %clang %s -S -o - -target aarch64-linux-gnu -mcpu=apple-a12  -mbranch-protection=pauthabi 2>&1 | FileCheck %s --check-prefix=PAUTH
+// Test that no error is generated if FEAT_PAUTH is supported:
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=apple-a12        -mbranch-protection=pauthabi 2>&1 | FileCheck %s --check-prefix=PAUTH
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -march=armv8.3-a       -mbranch-protection=pauthabi 2>&1 | FileCheck %s --check-prefix=PAUTH
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -march=armv9-a         -mbranch-protection=pauthabi 2>&1 | FileCheck %s --check-prefix=PAUTH
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -march=armv8.2-a+pauth -mbranch-protection=pauthabi 2>&1 | FileCheck %s --check-prefix=PAUTH
 
 // Test that the following options are still gated on -fptrauth-calls.
 // If they are not, in assertion builds they would fail at asm printing time:
 //
-// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-init-fini
-// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-function-pointer-type-discrimination
-// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-vtable-pointer-address-discrimination
-// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-vtable-pointer-type-discrimination
-// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-block-descriptor-pointers -fblocks -DBLOCKS
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-init-fini                                   2>&1 | FileCheck %s --check-prefix=WARN -DOPTION=-fptrauth-init-fini
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-function-pointer-type-discrimination        2>&1 | FileCheck %s --check-prefix=WARN -DOPTION=-fptrauth-function-pointer-type-discrimination
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-vtable-pointer-address-discrimination       2>&1 | FileCheck %s --check-prefix=WARN -DOPTION=-fptrauth-vtable-pointer-address-discrimination
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-vtable-pointer-type-discrimination          2>&1 | FileCheck %s --check-prefix=WARN -DOPTION=-fptrauth-vtable-pointer-type-discrimination
+// RUN: %clang %s -S -o - -target aarch64-linux-gnu -mcpu=cortex-a72 -fptrauth-block-descriptor-pointers -fblocks -DBLOCKS 2>&1 | FileCheck %s --check-prefix=WARN -DOPTION=-fptrauth-block-descriptor-pointers
 
 // Test that v8.2-compatible code is generated, if possible:
 //
@@ -45,7 +49,8 @@ int g(int (^bptr)(int)) {
 // FIXME At now, the error message is printed twice.
 // Ideally, this should be fixed, but it seems rather harmless.
 //
-// FAIL-COUNT-2: error: A feature is requested that needs CPU with Pointer Authentication support
+// FAIL-COUNT-2: error: neither FEAT_PAUTH nor -fptrauth-soft is enabled. Most of PAuth features are unavailable
+// WARN-COUNT-2: warning: [[OPTION]] is ignored because -fptrauth-calls is not specified
 
 // COMPAT: f:
 // COMPAT:   hint {{#25|#27}}
@@ -57,3 +62,7 @@ int g(int (^bptr)(int)) {
 // PAUTH:   paci{{[ab]}}sp
 //
 // PAUTH:   reta{{[ab]}}
+
+// Just check that some assembler output is printed.
+// WARN: f:
+// WARN:    ret