https://github.com/ahatanak updated
https://github.com/llvm/llvm-project/pull/144458
>From 180213a360c7b25784f84ada7112b30ee0bd1212 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatan...@apple.com>
Date: Fri, 13 Jun 2025 15:01:26 -0700
Subject: [PATCH 1/5] [Sema][ObjC] Loosen restrictions on reinterpret_cast
involving indirect ARC-managed pointers
Allow using reinterpret_cast for conversions between indirect ARC
pointers and other pointer types.
rdar://152905399
---
clang/include/clang/Sema/SemaObjC.h | 3 ++-
clang/lib/Sema/SemaCast.cpp | 11 +++++++----
clang/lib/Sema/SemaExprObjC.cpp | 14 ++++++++++----
clang/test/SemaObjCXX/arc-type-conversion.mm | 14 ++++++++++++--
4 files changed, 31 insertions(+), 11 deletions(-)
diff --git a/clang/include/clang/Sema/SemaObjC.h
b/clang/include/clang/Sema/SemaObjC.h
index b629c6d291402..ed08ff0acf89d 100644
--- a/clang/include/clang/Sema/SemaObjC.h
+++ b/clang/include/clang/Sema/SemaObjC.h
@@ -812,7 +812,8 @@ class SemaObjC : public SemaBase {
CheckedConversionKind CCK,
bool Diagnose = true,
bool DiagnoseCFAudited = false,
- BinaryOperatorKind Opc = BO_PtrMemD);
+ BinaryOperatorKind Opc = BO_PtrMemD,
+ bool IsReinterpretCast = false);
Expr *stripARCUnbridgedCast(Expr *e);
void diagnoseARCUnbridgedCast(Expr *e);
diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp
index 14e16bc39eb3a..e15a43c116516 100644
--- a/clang/lib/Sema/SemaCast.cpp
+++ b/clang/lib/Sema/SemaCast.cpp
@@ -161,12 +161,14 @@ namespace {
Self.CheckCastAlign(SrcExpr.get(), DestType, OpRange);
}
- void checkObjCConversion(CheckedConversionKind CCK) {
+ void checkObjCConversion(CheckedConversionKind CCK,
+ bool IsReinterpretCast = false) {
assert(Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers());
Expr *src = SrcExpr.get();
- if (Self.ObjC().CheckObjCConversion(OpRange, DestType, src, CCK) ==
- SemaObjC::ACR_unbridged)
+ if (Self.ObjC().CheckObjCConversion(
+ OpRange, DestType, src, CCK, true, false, BO_PtrMemD,
+ IsReinterpretCast) == SemaObjC::ACR_unbridged)
IsARCUnbridgedCast = true;
SrcExpr = src;
}
@@ -1263,7 +1265,8 @@ void CastOperation::CheckReinterpretCast() {
if (isValidCast(tcr)) {
if (Self.getLangOpts().allowsNonTrivialObjCLifetimeQualifiers())
- checkObjCConversion(CheckedConversionKind::OtherCast);
+ checkObjCConversion(CheckedConversionKind::OtherCast,
+ /*IsReinterpretCast=*/true);
DiagnoseReinterpretUpDownCast(Self, SrcExpr.get(), DestType, OpRange);
if (unsigned DiagID = checkCastFunctionType(Self, SrcExpr, DestType))
diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 3505d9f38d23c..59a2e660364de 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -4390,7 +4390,7 @@ SemaObjC::ARCConversionResult
SemaObjC::CheckObjCConversion(SourceRange castRange, QualType castType,
Expr *&castExpr, CheckedConversionKind CCK,
bool Diagnose, bool DiagnoseCFAudited,
- BinaryOperatorKind Opc) {
+ BinaryOperatorKind Opc, bool IsReinterpretCast) {
ASTContext &Context = getASTContext();
QualType castExprType = castExpr->getType();
@@ -4450,13 +4450,19 @@ SemaObjC::CheckObjCConversion(SourceRange castRange,
QualType castType,
// must be explicit.
// Allow conversions between pointers to lifetime types and coreFoundation
// pointers too, but only when the conversions are explicit.
+ // Allow conversions requested with a reinterpret_cast that converts an
+ // expression of type T* to type U*.
if (exprACTC == ACTC_indirectRetainable &&
(castACTC == ACTC_voidPtr ||
- (castACTC == ACTC_coreFoundation && SemaRef.isCast(CCK))))
+ (castACTC == ACTC_coreFoundation && SemaRef.isCast(CCK)) ||
+ (IsReinterpretCast && (effCastType->isPointerType() ||
+ effCastType->isObjCObjectPointerType()))))
return ACR_okay;
if (castACTC == ACTC_indirectRetainable &&
- (exprACTC == ACTC_voidPtr || exprACTC == ACTC_coreFoundation) &&
- SemaRef.isCast(CCK))
+ (((exprACTC == ACTC_voidPtr || exprACTC == ACTC_coreFoundation) &&
+ SemaRef.isCast(CCK)) ||
+ (IsReinterpretCast && (castExprType->isPointerType() ||
+ castExprType->isObjCObjectPointerType()))))
return ACR_okay;
switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
diff --git a/clang/test/SemaObjCXX/arc-type-conversion.mm
b/clang/test/SemaObjCXX/arc-type-conversion.mm
index 64cfd02ec18c0..2b44624121504 100644
--- a/clang/test/SemaObjCXX/arc-type-conversion.mm
+++ b/clang/test/SemaObjCXX/arc-type-conversion.mm
@@ -1,5 +1,7 @@
// RUN: %clang_cc1 -fobjc-runtime-has-weak -fsyntax-only -fobjc-arc -verify
-fblocks %s
+@class NSString;
+
void * cvt(id arg) // expected-note{{candidate function not viable: cannot
convert argument of incomplete type 'void *' to '__strong id'}}
{
void* voidp_val;
@@ -72,6 +74,16 @@ void test_reinterpret_cast(__strong id *sip, __weak id *wip,
(void)reinterpret_cast<__weak id *>(cwip); //
expected-error{{reinterpret_cast from '__weak id const *' to '__weak id *'
casts away qualifiers}}
(void)reinterpret_cast<__weak id *>(csip); //
expected-error{{reinterpret_cast from '__strong id const *' to '__weak id *'
casts away qualifiers}}
(void)reinterpret_cast<__strong id *>(cwip); //
expected-error{{reinterpret_cast from '__weak id const *' to '__strong id *'
casts away qualifiers}}
+
+ auto *p0 = reinterpret_cast<unsigned long *>(sip);
+ (void)reinterpret_cast<__strong id *>(p0);
+ auto *p1 = reinterpret_cast<__weak NSString *>(sip);
+ (void)reinterpret_cast<__strong id *>(p1);
+ (void)reinterpret_cast<unsigned long *>(csip); // expected-error
{{reinterpret_cast from '__strong id const *' to 'unsigned long *' casts away
qualifiers}}
+ const unsigned long *p2 = nullptr;
+ (void)reinterpret_cast<__strong id *>(p2); // expected-error
{{reinterpret_cast from 'const unsigned long *' to '__strong id *' casts away
qualifiers}}
+ auto ul = reinterpret_cast<unsigned long>(sip);
+ (void)reinterpret_cast<__strong id *>(ul); // expected-error {{cast of
'unsigned long' to '__strong id *' is disallowed with ARC}}
}
void test_cstyle_cast(__strong id *sip, __weak id *wip,
@@ -194,8 +206,6 @@ void from_void(void *vp) {
typedef void (^Block_strong)() __strong;
typedef void (^Block_autoreleasing)() __autoreleasing;
-@class NSString;
-
void ownership_transfer_in_cast(void *vp, Block *pblk) {
__strong NSString **sip2 = static_cast<NSString **>(static_cast<__strong id
*>(vp));
__strong NSString **&si2pref = static_cast<NSString **&>(sip2);
>From 1ce9dc056a4456c95567ee2741fa1d45600dfda3 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatan...@apple.com>
Date: Mon, 16 Jun 2025 19:05:13 -0700
Subject: [PATCH 2/5] Use isAnyPointerType()
---
clang/lib/Sema/SemaExprObjC.cpp | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index 59a2e660364de..395f2f340dbd6 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -4455,14 +4455,12 @@ SemaObjC::CheckObjCConversion(SourceRange castRange,
QualType castType,
if (exprACTC == ACTC_indirectRetainable &&
(castACTC == ACTC_voidPtr ||
(castACTC == ACTC_coreFoundation && SemaRef.isCast(CCK)) ||
- (IsReinterpretCast && (effCastType->isPointerType() ||
- effCastType->isObjCObjectPointerType()))))
+ (IsReinterpretCast && effCastType->isAnyPointerType())))
return ACR_okay;
if (castACTC == ACTC_indirectRetainable &&
(((exprACTC == ACTC_voidPtr || exprACTC == ACTC_coreFoundation) &&
SemaRef.isCast(CCK)) ||
- (IsReinterpretCast && (castExprType->isPointerType() ||
- castExprType->isObjCObjectPointerType()))))
+ (IsReinterpretCast && castExprType->isAnyPointerType())))
return ACR_okay;
switch (ARCCastChecker(Context, exprACTC, castACTC, false).Visit(castExpr)) {
>From 1a5777da63d7a396f717c1becdd4fbbd5625b71e Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatan...@apple.com>
Date: Mon, 16 Jun 2025 21:53:54 -0700
Subject: [PATCH 3/5] Fix test failure on Windows
---
clang/test/SemaObjCXX/arc-type-conversion.mm | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/clang/test/SemaObjCXX/arc-type-conversion.mm
b/clang/test/SemaObjCXX/arc-type-conversion.mm
index 2b44624121504..9c82cfa2bb2a7 100644
--- a/clang/test/SemaObjCXX/arc-type-conversion.mm
+++ b/clang/test/SemaObjCXX/arc-type-conversion.mm
@@ -1,6 +1,7 @@
// RUN: %clang_cc1 -fobjc-runtime-has-weak -fsyntax-only -fobjc-arc -verify
-fblocks %s
@class NSString;
+typedef unsigned __INTPTR_TYPE__ uintptr_t;
void * cvt(id arg) // expected-note{{candidate function not viable: cannot
convert argument of incomplete type 'void *' to '__strong id'}}
{
@@ -82,8 +83,8 @@ void test_reinterpret_cast(__strong id *sip, __weak id *wip,
(void)reinterpret_cast<unsigned long *>(csip); // expected-error
{{reinterpret_cast from '__strong id const *' to 'unsigned long *' casts away
qualifiers}}
const unsigned long *p2 = nullptr;
(void)reinterpret_cast<__strong id *>(p2); // expected-error
{{reinterpret_cast from 'const unsigned long *' to '__strong id *' casts away
qualifiers}}
- auto ul = reinterpret_cast<unsigned long>(sip);
- (void)reinterpret_cast<__strong id *>(ul); // expected-error {{cast of
'unsigned long' to '__strong id *' is disallowed with ARC}}
+ auto uip = reinterpret_cast<uintptr_t>(sip);
+ (void)reinterpret_cast<__strong id *>(uip); // expected-error {{to '__strong
id *' is disallowed with ARC}}
}
void test_cstyle_cast(__strong id *sip, __weak id *wip,
>From 92e7ad7507ef7c56208f1d63e1890bd72f10cb95 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahatan...@apple.com>
Date: Tue, 17 Jun 2025 09:11:56 -0700
Subject: [PATCH 4/5] Add a release note and test cases for const and volatile
pointers
---
clang/docs/ReleaseNotes.rst | 3 +++
clang/test/SemaObjCXX/arc-type-conversion.mm | 16 ++++++++++------
2 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index 59d9612268d30..bea39088c6380 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -325,6 +325,9 @@ Non-comprehensive list of changes in this release
``__reference_constructs_from_temporary`` should be used instead. (#GH44056)
- Added `__builtin_get_vtable_pointer` to directly load the primary vtable
pointer from a
polymorphic object.
+- Clang no longer rejects reinterpret_cast conversions between indirect
+ ARC-managed pointers and other pointer types. The prior behavior was overly
+ strict and inconsistent with the ARC specification.
New Compiler Flags
------------------
diff --git a/clang/test/SemaObjCXX/arc-type-conversion.mm
b/clang/test/SemaObjCXX/arc-type-conversion.mm
index 9c82cfa2bb2a7..a8e711cbe309d 100644
--- a/clang/test/SemaObjCXX/arc-type-conversion.mm
+++ b/clang/test/SemaObjCXX/arc-type-conversion.mm
@@ -76,13 +76,17 @@ void test_reinterpret_cast(__strong id *sip, __weak id *wip,
(void)reinterpret_cast<__weak id *>(csip); //
expected-error{{reinterpret_cast from '__strong id const *' to '__weak id *'
casts away qualifiers}}
(void)reinterpret_cast<__strong id *>(cwip); //
expected-error{{reinterpret_cast from '__weak id const *' to '__strong id *'
casts away qualifiers}}
- auto *p0 = reinterpret_cast<unsigned long *>(sip);
- (void)reinterpret_cast<__strong id *>(p0);
- auto *p1 = reinterpret_cast<__weak NSString *>(sip);
- (void)reinterpret_cast<__strong id *>(p1);
+ auto *ul = reinterpret_cast<unsigned long *>(sip);
+ (void)reinterpret_cast<__strong id *>(ul);
+ auto *wp = reinterpret_cast<__weak NSString *>(sip);
+ (void)reinterpret_cast<__strong id *>(wp);
(void)reinterpret_cast<unsigned long *>(csip); // expected-error
{{reinterpret_cast from '__strong id const *' to 'unsigned long *' casts away
qualifiers}}
- const unsigned long *p2 = nullptr;
- (void)reinterpret_cast<__strong id *>(p2); // expected-error
{{reinterpret_cast from 'const unsigned long *' to '__strong id *' casts away
qualifiers}}
+ const unsigned long *cul = nullptr;
+ (void)reinterpret_cast<__strong id *>(cul); // expected-error
{{reinterpret_cast from 'const unsigned long *' to '__strong id *' casts away
qualifiers}}
+ volatile __strong id *vsip = nullptr;
+ (void)reinterpret_cast<unsigned long *>(vsip); // expected-error
{{reinterpret_cast from '__strong id volatile *' to 'unsigned long *' casts
away qualifiers}}
+ volatile unsigned long *vul = nullptr;
+ (void)reinterpret_cast<__strong id *>(vul); // expected-error
{{reinterpret_cast from 'volatile unsigned long *' to '__strong id *' casts
away qualifiers}}
auto uip = reinterpret_cast<uintptr_t>(sip);
(void)reinterpret_cast<__strong id *>(uip); // expected-error {{to '__strong
id *' is disallowed with ARC}}
}
>From 889e109113345d0f221b7b0c05dfd084bbe93fc1 Mon Sep 17 00:00:00 2001
From: Akira Hatanaka <ahata...@gmail.com>
Date: Tue, 17 Jun 2025 18:13:34 -0700
Subject: [PATCH 5/5] Test casts which preserve qualifiers work as expected
---
clang/test/SemaObjCXX/arc-type-conversion.mm | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/clang/test/SemaObjCXX/arc-type-conversion.mm
b/clang/test/SemaObjCXX/arc-type-conversion.mm
index a8e711cbe309d..0d281bf3e5c45 100644
--- a/clang/test/SemaObjCXX/arc-type-conversion.mm
+++ b/clang/test/SemaObjCXX/arc-type-conversion.mm
@@ -81,12 +81,16 @@ void test_reinterpret_cast(__strong id *sip, __weak id *wip,
auto *wp = reinterpret_cast<__weak NSString *>(sip);
(void)reinterpret_cast<__strong id *>(wp);
(void)reinterpret_cast<unsigned long *>(csip); // expected-error
{{reinterpret_cast from '__strong id const *' to 'unsigned long *' casts away
qualifiers}}
+ (void)reinterpret_cast<const unsigned long *>(csip);
const unsigned long *cul = nullptr;
(void)reinterpret_cast<__strong id *>(cul); // expected-error
{{reinterpret_cast from 'const unsigned long *' to '__strong id *' casts away
qualifiers}}
+ (void)reinterpret_cast<const __strong id *>(cul);
volatile __strong id *vsip = nullptr;
(void)reinterpret_cast<unsigned long *>(vsip); // expected-error
{{reinterpret_cast from '__strong id volatile *' to 'unsigned long *' casts
away qualifiers}}
+ (void)reinterpret_cast<volatile unsigned long *>(vsip);
volatile unsigned long *vul = nullptr;
(void)reinterpret_cast<__strong id *>(vul); // expected-error
{{reinterpret_cast from 'volatile unsigned long *' to '__strong id *' casts
away qualifiers}}
+ (void)reinterpret_cast<volatile __strong id *>(vul);
auto uip = reinterpret_cast<uintptr_t>(sip);
(void)reinterpret_cast<__strong id *>(uip); // expected-error {{to '__strong
id *' is disallowed with ARC}}
}
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