https://github.com/ojhunt created
https://github.com/llvm/llvm-project/pull/153912
For backwards compatibility reasons the ptrauth_qualifier and ptrauth_intrinsic
features need to be testable with __has_feature() on Apple platforms, but for
other platforms this backwards compatibility issue does not exist.
This PR resolves these issues by making the ptrauth_qualifier and
ptrauth_intrinsic tests conditional upon a darwin target. This also allows us
to revert the ptrauth_qualifier check from an extension to a feature test
again, as is required on these platforms.
At the same time we introduce a new predefined macro __PTRAUTH__ that answers
the same question as __has_feature(ptrauth_qualifier) and
__has_feature(ptrauth_intrinsic) as those tests are synonymous and only exist
separately for compatibility reasons.
The requirement to test for the __PTRAUTH__ macro also resolves the hazard
presented by mixing the ptrauth_qualifier flag (that impacts ABI and security
policies) with -pedantics-errors, which makes __has_extension return false for
all extensions.
>From ea731927d6bdf85a3cdb333b756447658f2c2ea6 Mon Sep 17 00:00:00 2001
From: Oliver Hunt <oli...@apple.com>
Date: Fri, 15 Aug 2025 18:40:12 -0700
Subject: [PATCH] [clang][PAC] Make ptrauth_qualifier and ptrauth_intrinsic
Darwin only features
For backwards compatibility reasons the ptrauth_qualifier and ptrauth_intrinsic
features need to be testable with __has_feature() on Apple platforms, but for
other platforms this backwards compatibility issue does not exist.
This PR resolves these issues by making the ptrauth_qualifier and
ptrauth_intrinsic tests conditional upon a darwin target. This also
allows us to revert the ptrauth_qualifier check from an extension to a
feature test again, as is required on these platforms.
At the same time we introduce a new predefined macro __PTRAUTH__
that answers the same question as __has_feature(ptrauth_qualifier)
and __has_feature(ptrauth_intrinsic) as those tests are synonymous
and only exist separately for compatibility reasons.
The requirement to test for the __PTRAUTH__ macro also resolves the
hazard presented by mixing the ptrauth_qualifier flag (that impacts
ABI and security policies) with -pedantics-errors, which makes
__has_extension return false for all extensions.
---
clang/include/clang/Basic/Features.def | 4 +--
clang/lib/Frontend/FrontendActions.cpp | 1 +
clang/lib/Frontend/InitPreprocessor.cpp | 3 +++
clang/lib/Headers/ptrauth.h | 4 +--
clang/lib/Lex/PPMacroExpansion.cpp | 1 +
clang/test/Preprocessor/ptrauth_extension.c | 30 ++++++++++++++++++---
clang/test/Preprocessor/ptrauth_feature.c | 2 +-
clang/test/Sema/ptrauth-qualifier.c | 16 +++++++++--
clang/test/SemaObjC/ptrauth-qualifier.m | 16 +++++++++--
9 files changed, 64 insertions(+), 13 deletions(-)
diff --git a/clang/include/clang/Basic/Features.def
b/clang/include/clang/Basic/Features.def
index b9efc6a6a2e9d..6f414105d7c36 100644
--- a/clang/include/clang/Basic/Features.def
+++ b/clang/include/clang/Basic/Features.def
@@ -147,8 +147,8 @@ FEATURE(type_sanitizer,
LangOpts.Sanitize.has(SanitizerKind::Type))
FEATURE(thread_sanitizer, LangOpts.Sanitize.has(SanitizerKind::Thread))
FEATURE(dataflow_sanitizer, LangOpts.Sanitize.has(SanitizerKind::DataFlow))
FEATURE(scudo, LangOpts.Sanitize.hasOneOf(SanitizerKind::Scudo))
-FEATURE(ptrauth_intrinsics, LangOpts.PointerAuthIntrinsics)
-EXTENSION(ptrauth_qualifier, LangOpts.PointerAuthIntrinsics)
+FEATURE(ptrauth_intrinsics, LangOpts.PointerAuthIntrinsics &&
Target.getTriple().isOSDarwin())
+FEATURE(ptrauth_qualifier, LangOpts.PointerAuthIntrinsics &&
Target.getTriple().isOSDarwin())
FEATURE(ptrauth_calls, LangOpts.PointerAuthCalls)
FEATURE(ptrauth_returns, LangOpts.PointerAuthReturns)
FEATURE(ptrauth_vtable_pointer_address_discrimination,
LangOpts.PointerAuthVTPtrAddressDiscrimination)
diff --git a/clang/lib/Frontend/FrontendActions.cpp
b/clang/lib/Frontend/FrontendActions.cpp
index 685a9bbf2cde9..d29a08c43fc12 100644
--- a/clang/lib/Frontend/FrontendActions.cpp
+++ b/clang/lib/Frontend/FrontendActions.cpp
@@ -1159,6 +1159,7 @@ void DumpCompilerOptionsAction::ExecuteAction() {
raw_ostream &OS = *OSP;
const Preprocessor &PP = CI.getPreprocessor();
const LangOptions &LangOpts = PP.getLangOpts();
+ const TargetInfo &Target = CI.getTarget();
// FIXME: Rather than manually format the JSON (which is awkward due to
// needing to remove trailing commas), this should make use of a JSON
library.
diff --git a/clang/lib/Frontend/InitPreprocessor.cpp
b/clang/lib/Frontend/InitPreprocessor.cpp
index 008a35d5265e1..accddfebc0f6f 100644
--- a/clang/lib/Frontend/InitPreprocessor.cpp
+++ b/clang/lib/Frontend/InitPreprocessor.cpp
@@ -1528,6 +1528,9 @@ static void InitializePredefinedMacros(const TargetInfo
&TI,
#undef TARGET_OS
}
+ if (LangOpts.PointerAuthIntrinsics)
+ Builder.defineMacro("__PTRAUTH__");
+
// Get other target #defines.
TI.getTargetDefines(LangOpts, Builder);
}
diff --git a/clang/lib/Headers/ptrauth.h b/clang/lib/Headers/ptrauth.h
index 7f7d387cbdfda..f902ca1e3bbd3 100644
--- a/clang/lib/Headers/ptrauth.h
+++ b/clang/lib/Headers/ptrauth.h
@@ -95,7 +95,7 @@ typedef __UINTPTR_TYPE__ ptrauth_generic_signature_t;
__ptrauth qualifier; the compiler will perform this check
automatically. */
-#if __has_feature(ptrauth_intrinsics)
+#if __has_feature(ptrauth_intrinsics) || defined(__PTRAUTH__)
/* Strip the signature from a value without authenticating it.
@@ -388,6 +388,6 @@ typedef __UINTPTR_TYPE__ ptrauth_generic_signature_t;
#define __ptrauth_objc_isa_uintptr
#define __ptrauth_objc_super_pointer
-#endif /* __has_feature(ptrauth_intrinsics) */
+#endif /* __has_feature(ptrauth_intrinsics) || defined(__PTRAUTH__) */
#endif /* __PTRAUTH_H */
diff --git a/clang/lib/Lex/PPMacroExpansion.cpp
b/clang/lib/Lex/PPMacroExpansion.cpp
index 6f12ac80d677e..f9dfd0eb14bc0 100644
--- a/clang/lib/Lex/PPMacroExpansion.cpp
+++ b/clang/lib/Lex/PPMacroExpansion.cpp
@@ -1089,6 +1089,7 @@ static void ComputeDATE_TIME(SourceLocation &DATELoc,
SourceLocation &TIMELoc,
/// specified by the identifier as a standard language feature.
static bool HasFeature(const Preprocessor &PP, StringRef Feature) {
const LangOptions &LangOpts = PP.getLangOpts();
+ const TargetInfo &Target = PP.getTargetInfo();
// Normalize the feature name, __foo__ becomes foo.
if (Feature.starts_with("__") && Feature.ends_with("__") &&
diff --git a/clang/test/Preprocessor/ptrauth_extension.c
b/clang/test/Preprocessor/ptrauth_extension.c
index d6b79187ba62d..3267b0786c28f 100644
--- a/clang/test/Preprocessor/ptrauth_extension.c
+++ b/clang/test/Preprocessor/ptrauth_extension.c
@@ -4,10 +4,32 @@
// RUN: %clang_cc1 -E %s -triple=aarch64 -fptrauth-calls | \
// RUN: FileCheck %s --check-prefixes=NOINTRIN
-#if __has_extension(ptrauth_qualifier)
-// INTRIN: has_ptrauth_qualifier
-void has_ptrauth_qualifier() {}
-#else
+// RUN: %clang_cc1 -E %s -DIS_DARWIN -triple=arm64e-apple-darwin
-fptrauth-intrinsics | \
+// RUN: FileCheck %s --check-prefixes=INTRIN,INTRIN_MAC
+
+// RUN: %clang_cc1 -E %s -DIS_DARWIN -triple=arm64e-apple-darwin
-fptrauth-calls | \
+// RUN: FileCheck %s --check-prefixes=NOINTRIN
+
+#if defined(IS_DARWIN) && __has_extension(ptrauth_qualifier)
+// INTRIN_MAC: has_ptrauth_qualifier1
+void has_ptrauth_qualifier1() {}
+#ifndef __PTRAUTH__
+#error ptrauth_qualifier extension present without predefined test macro
+#endif
+#endif
+#if defined(IS_DARWIN) && __has_feature(ptrauth_qualifier)
+// INTRIN_MAC: has_ptrauth_qualifier2
+void has_ptrauth_qualifier2() {}
+#ifndef __PTRAUTH__
+#error ptrauth_qualifier extension present without predefined test macro
+#endif
+#endif
+#if defined(__PTRAUTH__)
+// INTRIN: has_ptrauth_qualifier3
+void has_ptrauth_qualifier3() {}
+#endif
+
+#if !defined(__PTRAUTH__) && !__has_feature(ptrauth_qualifier) &&
!__has_extension(ptrauth_qualifier)
// NOINTRIN: no_ptrauth_qualifier
void no_ptrauth_qualifier() {}
#endif
diff --git a/clang/test/Preprocessor/ptrauth_feature.c
b/clang/test/Preprocessor/ptrauth_feature.c
index a440791d6cc69..45d9cd4245dba 100644
--- a/clang/test/Preprocessor/ptrauth_feature.c
+++ b/clang/test/Preprocessor/ptrauth_feature.c
@@ -34,7 +34,7 @@
// RUN: %clang_cc1 -E %s -triple=aarch64 -fptrauth-elf-got | \
// RUN: FileCheck %s
--check-prefixes=NOINTRIN,NOCALLS,NORETS,NOVPTR_ADDR_DISCR,NOVPTR_TYPE_DISCR,NOTYPE_INFO_DISCR,NOFUNC,NOINITFINI,NOINITFINI_ADDR_DISCR,NOGOTOS,ELFGOT
-#if __has_feature(ptrauth_intrinsics)
+#if defined(__PTRAUTH__)
// INTRIN: has_ptrauth_intrinsics
void has_ptrauth_intrinsics() {}
#else
diff --git a/clang/test/Sema/ptrauth-qualifier.c
b/clang/test/Sema/ptrauth-qualifier.c
index 5d932b724f07a..3e568ce9f37e3 100644
--- a/clang/test/Sema/ptrauth-qualifier.c
+++ b/clang/test/Sema/ptrauth-qualifier.c
@@ -1,13 +1,25 @@
-// RUN: %clang_cc1 -triple arm64-apple-ios -std=c23 -fsyntax-only -verify
-fptrauth-intrinsics %s
+// RUN: %clang_cc1 -triple arm64-apple-ios -DIS_DARWIN -std=c23 -fsyntax-only
-verify -fptrauth-intrinsics %s
// RUN: %clang_cc1 -triple aarch64-linux-gnu -std=c23 -fsyntax-only -verify
-fptrauth-intrinsics %s
-#if !__has_extension(ptrauth_qualifier)
+#if defined(IS_DARWIN) && !__has_extension(ptrauth_qualifier)
// This error means that the __ptrauth qualifier availability test says that
it
// is not available. This error is not expected in the output, if it is seen
// there is a feature detection regression.
#error __ptrauth qualifier not enabled
#endif
+#if defined(IS_DARWIN) && !__has_feature(ptrauth_qualifier)
+// This error means that the __has_feature test for ptrauth_qualifier has
+// failed, despite it being expected on darwin.
+#error __ptrauth qualifier not enabled
+#elif !defined(IS_DARWIN) && (__has_feature(ptrauth_qualifier) ||
__has_extension(ptrauth_qualifier))
+#error ptrauth_qualifier labeled a feature on a non-darwin platform
+#endif
+
+#if !defined (__PTRAUTH__)
+#error __PTRAUTH__ test macro not defined when ptrauth is enabled
+#endif
+
#if __aarch64__
#define VALID_CODE_KEY 0
#define VALID_DATA_KEY 2
diff --git a/clang/test/SemaObjC/ptrauth-qualifier.m
b/clang/test/SemaObjC/ptrauth-qualifier.m
index 74bbe6f09899b..67a73bbe45777 100644
--- a/clang/test/SemaObjC/ptrauth-qualifier.m
+++ b/clang/test/SemaObjC/ptrauth-qualifier.m
@@ -1,13 +1,25 @@
-// RUN: %clang_cc1 -triple arm64-apple-ios -fsyntax-only -verify
-fptrauth-intrinsics %s
+// RUN: %clang_cc1 -triple arm64-apple-ios -DIS_DARWIN -fsyntax-only -verify
-fptrauth-intrinsics %s
// RUN: %clang_cc1 -triple aarch64-linux-gnu -fsyntax-only -verify
-fptrauth-intrinsics %s
-#if !__has_extension(ptrauth_qualifier)
+#if defined(IS_DARWIN) && !__has_extension(ptrauth_qualifier)
// This error means that the __ptrauth qualifier availability test says that
it
// is not available. This error is not expected in the output, if it is seen
// there is a feature detection regression.
#error __ptrauth qualifier not enabled
#endif
+#if defined(IS_DARWIN) && !__has_feature(ptrauth_qualifier)
+// This error means that the __has_feature test for ptrauth_qualifier has
+// failed, despite it being expected on darwin.
+#error __ptrauth qualifier not enabled
+#elif !defined(IS_DARWIN) && (__has_feature(ptrauth_qualifier) ||
__has_extension(ptrauth_qualifier))
+#error ptrauth_qualifier labeled a feature on a non-darwin platform
+#endif
+
+#if !defined (__PTRAUTH__)
+#error __PTRAUTH__ test macro not defined when ptrauth is enabled
+#endif
+
@interface Foo
// expected-warning@-1 {{class 'Foo' defined without specifying a base class}}
// expected-note@-2 {{add a super class to fix this problem}}
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