[clang] Enable pointer authentication auth-failure traps.

Author: ahmedbougacha

clang/include/clang/Basic/PointerAuthOptions.h

@@ -166,6 +166,9 @@ struct PointerAuthOptions {
   /// Do indirect goto label addresses need to be authenticated?
   bool IndirectGotos = false;
 
+  /// Do authentication failures cause a trap?
+  bool AuthTraps = false;
+
   /// The ABI for C function pointers.
   PointerAuthSchema FunctionPointers;
 

clang/lib/CodeGen/CodeGenFunction.cpp

@@ -884,6 +884,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
     Fn->addFnAttr("ptrauth-calls");
   if (CodeGenOpts.PointerAuth.IndirectGotos)
     Fn->addFnAttr("ptrauth-indirect-gotos");
+  if (CodeGenOpts.PointerAuth.AuthTraps)
+    Fn->addFnAttr("ptrauth-auth-traps");
 
   // Apply xray attributes to the function (as a string, for now)
   bool AlwaysXRayAttr = false;

clang/lib/Frontend/CompilerInvocation.cpp

@@ -1511,13 +1511,15 @@ void CompilerInvocation::setDefaultPointerAuthOptions(
     }
   }
   Opts.IndirectGotos = LangOpts.PointerAuthIndirectGotos;
+  Opts.AuthTraps = LangOpts.PointerAuthAuthTraps;
 }
 
 static void parsePointerAuthOptions(PointerAuthOptions &Opts,
                                     const LangOptions &LangOpts,
                                     const llvm::Triple &Triple,
                                     DiagnosticsEngine &Diags) {
-  if (!LangOpts.PointerAuthCalls && !LangOpts.PointerAuthIndirectGotos)
+  if (!LangOpts.PointerAuthCalls && !LangOpts.PointerAuthIndirectGotos &&
+      !LangOpts.PointerAuthAuthTraps)
     return;
 
   CompilerInvocation::setDefaultPointerAuthOptions(Opts, LangOpts, Triple);

clang/test/CodeGen/ptrauth-function-attributes.c

@@ -8,6 +8,9 @@
 // RUN: %clang_cc1 -triple arm64e-apple-ios  -fptrauth-indirect-gotos -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,GOTOS
 // RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-indirect-gotos -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,GOTOS
 
+// RUN: %clang_cc1 -triple arm64e-apple-ios  -fptrauth-auth-traps -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,TRAPS
+// RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-auth-traps -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,TRAPS
+
 // ALL: define {{(dso_local )?}}void @test() #0
 void test() {
 }
@@ -16,4 +19,6 @@ void test() {
 
 // GOTOS: attributes #0 = {{{.*}} "ptrauth-indirect-gotos" {{.*}}}
 
+// TRAPS: attributes #0 = {{{.*}} "ptrauth-auth-traps" {{.*}}}
+
 // OFF-NOT: attributes {{.*}} "ptrauth-