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[clang][PAC] ptrauth_qualifier and ptrauth_intrinsic should only be available on Darwin #153912

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Merged
ojhunt merged 8 commits into from
Aug 18, 2025
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[clang][PAC] ptrauth_qualifier and ptrauth_intrinsic should only be available on Darwin #153912

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ea73192
[clang][PAC] Make ptrauth_qualifier and ptrauth_intrinsic Darwin only…
ojhunt Aug 16, 2025
ee8c1ae
Add release note
ojhunt Aug 18, 2025
b1b2de3
Update clang/docs/ReleaseNotes.rst
ojhunt Aug 18, 2025
bade8f3
Revert addition of a new declaration requirement
ojhunt Aug 18, 2025
3316f38
remove added lines
ojhunt Aug 18, 2025
e993782
Move release note
ojhunt Aug 18, 2025
9cb052c
Merge branch 'main' into users/ojhunt/de-and-re-featurify-ptrauth-qua…
ojhunt Aug 18, 2025
a78ae13
Merge branch 'main' into users/ojhunt/de-and-re-featurify-ptrauth-qua…
ojhunt Aug 18, 2025
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4 changes: 2 additions & 2 deletions clang/include/clang/Basic/Features.def
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Expand Up @@ -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())
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@ojhunt ojhunt Aug 16, 2025

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both of these are clearly identical so I figured making them both darwin only given PTRAUTH serves the purpose for everything

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)
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1 change: 1 addition & 0 deletions clang/lib/Frontend/FrontendActions.cpp
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Expand Up @@ -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.
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3 changes: 3 additions & 0 deletions clang/lib/Frontend/InitPreprocessor.cpp
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Expand Up @@ -1528,6 +1528,9 @@ static void InitializePredefinedMacros(const TargetInfo &TI,
#undef TARGET_OS
}

if (LangOpts.PointerAuthIntrinsics)
Builder.defineMacro("__PTRAUTH__");
Comment on lines +1538 to +1539
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@cor3ntin cor3ntin Aug 16, 2025

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Did we synchronize with GCC here (or does gcc not support this feature at all yet?)

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@ojhunt ojhunt Aug 16, 2025

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I don't believe gcc has any support as yet? I recall talking to one gcc person in Sofia but it didn't sound like it's high priority.

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@ojhunt ojhunt Aug 16, 2025

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Ok, so there's an existing __ARM_FEATURE_PAUTH but that does not cover the language features.
Naming-wise do we want something along the lines of __ARM_FEATURE_PAUTH_LANG_SUPPORT__ ?

__ARM_FEATURE_PAUTH only indicates the target supports the features -- gcc doesn't provide anything more than that afaict

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@ojhunt ojhunt Aug 16, 2025

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(we have __ARM_FEATURE_PAUTH already)

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@cor3ntin cor3ntin Aug 16, 2025 •
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there is also __ARM_FEATURE_PAC_DEFAULT, apparently. But this seems fairly target-related.
I'm fine with __PTRAUTH__ (or __PTRAUTH)

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@ojhunt ojhunt Aug 16, 2025

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I think @AaronBallman had an opinion on the __ suffix - I am absolutely indifferent here and as demonstrated am terrible at names :D

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@AaronBallman AaronBallman Aug 18, 2025

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I'm happy with __PTRAUTH__; do we want it to expand to a particular value so we can change the value to have the macro mean a different feature set is enabled?

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@ojhunt ojhunt Aug 18, 2025

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I think the complexity of the ptrauth abi surface area means that I don't think any single value can really represent it - there's significant variation for us in userspace vs kernel vs other constrained environments vs what the linux folk are doing.

I think any dev who does need to work at this level will need to be directly detecting each single mode that is active


// Get other target #defines.
TI.getTargetDefines(LangOpts, Builder);
}
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4 changes: 2 additions & 2 deletions clang/lib/Headers/ptrauth.h
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Expand Up @@ -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.

Expand Down Expand Up @@ -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 */
1 change: 1 addition & 0 deletions clang/lib/Lex/PPMacroExpansion.cpp
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Expand Up @@ -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();
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@cor3ntin cor3ntin Aug 16, 2025

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This looks unused

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@ojhunt ojhunt Aug 16, 2025

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It's used in the FEATURE() macro below for the darwin restriction on the feature checks

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@AaronBallman AaronBallman Aug 18, 2025

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Please update the comment at the top of Features.def to explain this variable is also available.

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@ojhunt ojhunt Aug 18, 2025

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I realized that this increases the number of decls required for FEATURE, and I'm just pulling the target off PP anyway, so I'll just inline that in the expression.


// Normalize the feature name, __foo__ becomes foo.
if (Feature.starts_with("__") && Feature.ends_with("__") &&
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30 changes: 26 additions & 4 deletions clang/test/Preprocessor/ptrauth_extension.c
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Expand Up @@ -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
2 changes: 1 addition & 1 deletion clang/test/Preprocessor/ptrauth_feature.c
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Expand Up @@ -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
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16 changes: 14 additions & 2 deletions clang/test/Sema/ptrauth-qualifier.c
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@@ -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
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16 changes: 14 additions & 2 deletions clang/test/SemaObjC/ptrauth-qualifier.m
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@@ -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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