[clang] [clang] Implement -fptrauth-auth-traps. (PR #102417)

[Ahmed Bougacha via cfe-commits]

https://github.com/ahmedbougacha updated https://github.com/llvm/llvm-project/pull/102417

>From 241ecf478c0cc0e929ffef3532cc2cb625781a71 Mon Sep 17 00:00:00 2001
From: Ahmed Bougacha <ahmed at bougacha.org>
Date: Fri, 9 Aug 2024 12:26:20 -0700
Subject: [PATCH] [clang] Enable pointer authentication auth-failure traps.

---
 clang/include/clang/Basic/PointerAuthOptions.h   | 3 +++
 clang/lib/CodeGen/CodeGenFunction.cpp            | 2 ++
 clang/lib/Frontend/CompilerInvocation.cpp        | 7 ++++---
 clang/test/CodeGen/ptrauth-function-attributes.c | 5 +++++
 4 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/clang/include/clang/Basic/PointerAuthOptions.h b/clang/include/clang/Basic/PointerAuthOptions.h
index a847bf4a4b4f6d..3deb666b375136 100644
--- a/clang/include/clang/Basic/PointerAuthOptions.h
+++ b/clang/include/clang/Basic/PointerAuthOptions.h
@@ -166,6 +166,9 @@ struct PointerAuthOptions {
   /// Should return addresses be authenticated?
   bool ReturnAddresses = false;
 
+  /// Do authentication failures cause a trap?
+  bool AuthTraps = false;
+
   /// Do indirect goto label addresses need to be authenticated?
   bool IndirectGotos = false;
 
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 4dc57d0ff5b269..2b2e23f1e5d7fb 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -884,6 +884,8 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
     Fn->addFnAttr("ptrauth-returns");
   if (CodeGenOpts.PointerAuth.FunctionPointers)
     Fn->addFnAttr("ptrauth-calls");
+  if (CodeGenOpts.PointerAuth.AuthTraps)
+    Fn->addFnAttr("ptrauth-auth-traps");
   if (CodeGenOpts.PointerAuth.IndirectGotos)
     Fn->addFnAttr("ptrauth-indirect-gotos");
 
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 4370342ab22f31..e3911c281985b7 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1510,16 +1510,17 @@ void CompilerInvocation::setDefaultPointerAuthOptions(
           Discrimination::Constant, InitFiniPointerConstantDiscriminator);
     }
   }
-  Opts.IndirectGotos = LangOpts.PointerAuthIndirectGotos;
   Opts.ReturnAddresses = LangOpts.PointerAuthReturns;
+  Opts.AuthTraps = LangOpts.PointerAuthAuthTraps;
+  Opts.IndirectGotos = LangOpts.PointerAuthIndirectGotos;
 }
 
 static void parsePointerAuthOptions(PointerAuthOptions &Opts,
                                     const LangOptions &LangOpts,
                                     const llvm::Triple &Triple,
                                     DiagnosticsEngine &Diags) {
-  if (!LangOpts.PointerAuthCalls && !LangOpts.PointerAuthIndirectGotos &&
-      !LangOpts.PointerAuthReturns)
+  if (!LangOpts.PointerAuthCalls && !LangOpts.PointerAuthReturns &&
+      !LangOpts.PointerAuthAuthTraps && !LangOpts.PointerAuthIndirectGotos)
     return;
 
   CompilerInvocation::setDefaultPointerAuthOptions(Opts, LangOpts, Triple);
diff --git a/clang/test/CodeGen/ptrauth-function-attributes.c b/clang/test/CodeGen/ptrauth-function-attributes.c
index 17ebf9d6e2e01c..e7081f00b4f686 100644
--- a/clang/test/CodeGen/ptrauth-function-attributes.c
+++ b/clang/test/CodeGen/ptrauth-function-attributes.c
@@ -8,6 +8,9 @@
 // RUN: %clang_cc1 -triple arm64-apple-ios   -fptrauth-returns -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,RETS
 // RUN: %clang_cc1 -triple aarch64-linux-gnu -fptrauth-returns -emit-llvm %s -o - | FileCheck %s --check-prefixes=ALL,RETS
 
+// RUN: %clang_cc1 -triple arm64-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
+
 // RUN: %clang_cc1 -triple arm64-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
 
@@ -19,6 +22,8 @@ void test() {
 
 // RETS: attributes #0 = {{{.*}} "ptrauth-returns" {{.*}}}
 
+// TRAPS: attributes #0 = {{{.*}} "ptrauth-auth-traps" {{.*}}}
+
 // GOTOS: attributes #0 = {{{.*}} "ptrauth-indirect-gotos" {{.*}}}
 
 // OFF-NOT: attributes {{.*}} "ptrauth-