ahatanak created this revision.
ahatanak added reviewers: rjmccall, rsmith.
This patch fixes a bug in r328731 that caused structs with `__weak` fields to
be passed in registers. This happens when a struct doesn't have a `__weak`
field but one of its subobjects does. To fix this, I added flag
CXXRecordDecl::CannotPassInRegisters that propagates outwards and tracks
whether a `__weak` field was seen. I added a new flag instead of reusing the
CanPassInRegisters flag since in C++ we cannot always determine the value of a
class' CanPassInRegisters flag by looking at its subobject's CanPassInRegisters
flag (CanPassInRegisters=true in the subclass doesn't mean
CanPassInRegisters=true in the derived class in C++).
rdar://problem/39194693
Repository:
rC Clang
https://reviews.llvm.org/D45384
Files:
include/clang/AST/DeclCXX.h
lib/AST/ASTImporter.cpp
lib/AST/DeclCXX.cpp
lib/Sema/SemaDeclCXX.cpp
lib/Serialization/ASTReaderDecl.cpp
lib/Serialization/ASTWriter.cpp
test/CodeGenObjCXX/objc-struct-cxx-abi.mm
Index: test/CodeGenObjCXX/objc-struct-cxx-abi.mm
===================================================================
--- test/CodeGenObjCXX/objc-struct-cxx-abi.mm
+++ test/CodeGenObjCXX/objc-struct-cxx-abi.mm
@@ -8,6 +8,8 @@
// pointer fields are passed directly.
// CHECK: %[[STRUCT_STRONGWEAK:.*]] = type { i8*, i8* }
+// CHECK: %[[STRUCT_CONTAINSSTRONGWEAK:.*]] = type { %[[STRUCT_STRONGWEAK]] }
+// CHECK: %[[STRUCT_DERIVEDSTRONGWEAK:.*]] = type { %[[STRUCT_STRONGWEAK]] }
// CHECK: %[[STRUCT_STRONG:.*]] = type { i8* }
// CHECK: %[[STRUCT_S:.*]] = type { i8* }
// CHECK: %[[STRUCT_CONTAINSNONTRIVIAL:.*]] = type { %{{.*}}, i8* }
@@ -21,6 +23,21 @@
__weak id fweak;
};
+#ifdef TRIVIALABI
+struct __attribute__((trivial_abi)) ContainsStrongWeak {
+#else
+struct ContainsStrongWeak {
+#endif
+ StrongWeak sw;
+};
+
+#ifdef TRIVIALABI
+struct __attribute__((trivial_abi)) DerivedStrongWeak : StrongWeak {
+#else
+struct DerivedStrongWeak : StrongWeak {
+#endif
+};
+
#ifdef TRIVIALABI
struct __attribute__((trivial_abi)) Strong {
#else
@@ -84,6 +101,18 @@
return *a;
}
+// CHECK: define void @_Z27testParamContainsStrongWeak18ContainsStrongWeak(%[[STRUCT_CONTAINSSTRONGWEAK]]* %[[A:.*]])
+// CHECK: call %[[STRUCT_CONTAINSSTRONGWEAK]]* @_ZN18ContainsStrongWeakD1Ev(%[[STRUCT_CONTAINSSTRONGWEAK]]* %[[A]])
+
+void testParamContainsStrongWeak(ContainsStrongWeak a) {
+}
+
+// CHECK: define void @_Z26testParamDerivedStrongWeak17DerivedStrongWeak(%[[STRUCT_DERIVEDSTRONGWEAK]]* %[[A:.*]])
+// CHECK: call %[[STRUCT_DERIVEDSTRONGWEAK]]* @_ZN17DerivedStrongWeakD1Ev(%[[STRUCT_DERIVEDSTRONGWEAK]]* %[[A]])
+
+void testParamDerivedStrongWeak(DerivedStrongWeak a) {
+}
+
// CHECK: define void @_Z15testParamStrong6Strong(i64 %[[A_COERCE:.*]])
// CHECK: %[[A:.*]] = alloca %[[STRUCT_STRONG]], align 8
// CHECK: %[[COERCE_DIVE:.*]] = getelementptr inbounds %[[STRUCT_STRONG]], %[[STRUCT_STRONG]]* %[[A]], i32 0, i32 0
Index: lib/Serialization/ASTWriter.cpp
===================================================================
--- lib/Serialization/ASTWriter.cpp
+++ lib/Serialization/ASTWriter.cpp
@@ -6024,6 +6024,7 @@
Record->push_back(Data.HasIrrelevantDestructor);
Record->push_back(Data.HasConstexprNonCopyMoveConstructor);
Record->push_back(Data.HasDefaultedDefaultConstructor);
+ Record->push_back(Data.CannotPassInRegisters);
Record->push_back(Data.DefaultedDefaultConstructorIsConstexpr);
Record->push_back(Data.HasConstexprDefaultConstructor);
Record->push_back(Data.HasNonLiteralTypeFieldsOrBases);
Index: lib/Serialization/ASTReaderDecl.cpp
===================================================================
--- lib/Serialization/ASTReaderDecl.cpp
+++ lib/Serialization/ASTReaderDecl.cpp
@@ -1592,6 +1592,7 @@
Data.HasIrrelevantDestructor = Record.readInt();
Data.HasConstexprNonCopyMoveConstructor = Record.readInt();
Data.HasDefaultedDefaultConstructor = Record.readInt();
+ Data.CannotPassInRegisters = Record.readInt();
Data.DefaultedDefaultConstructorIsConstexpr = Record.readInt();
Data.HasConstexprDefaultConstructor = Record.readInt();
Data.HasNonLiteralTypeFieldsOrBases = Record.readInt();
@@ -1733,6 +1734,7 @@
MATCH_FIELD(HasIrrelevantDestructor)
OR_FIELD(HasConstexprNonCopyMoveConstructor)
OR_FIELD(HasDefaultedDefaultConstructor)
+ MATCH_FIELD(CannotPassInRegisters)
MATCH_FIELD(DefaultedDefaultConstructorIsConstexpr)
OR_FIELD(HasConstexprDefaultConstructor)
MATCH_FIELD(HasNonLiteralTypeFieldsOrBases)
Index: lib/Sema/SemaDeclCXX.cpp
===================================================================
--- lib/Sema/SemaDeclCXX.cpp
+++ lib/Sema/SemaDeclCXX.cpp
@@ -5854,9 +5854,9 @@
if (RD->isDependentType() || RD->isInvalidDecl())
return true;
- // The param cannot be passed in registers if CanPassInRegisters is already
- // set to false.
- if (!RD->canPassInRegisters())
+ // The param cannot be passed in registers if CannotPassInRegisters is set to
+ // true.
+ if (RD->cannotPassInRegisters())
return false;
if (CCK != TargetInfo::CCK_MicrosoftX86_64)
Index: lib/AST/DeclCXX.cpp
===================================================================
--- lib/AST/DeclCXX.cpp
+++ lib/AST/DeclCXX.cpp
@@ -93,7 +93,7 @@
DeclaredNonTrivialSpecialMembers(0),
DeclaredNonTrivialSpecialMembersForCall(0), HasIrrelevantDestructor(true),
HasConstexprNonCopyMoveConstructor(false),
- HasDefaultedDefaultConstructor(false),
+ HasDefaultedDefaultConstructor(false), CannotPassInRegisters(false),
DefaultedDefaultConstructorIsConstexpr(true),
HasConstexprDefaultConstructor(false),
HasNonLiteralTypeFieldsOrBases(false), ComputedVisibleConversions(false),
@@ -421,6 +421,9 @@
if (BaseClassDecl->hasVolatileMember())
setHasVolatileMember(true);
+ if (BaseClassDecl->cannotPassInRegisters())
+ setCannotPassInRegisters(true);
+
// Keep track of the presence of mutable fields.
if (BaseClassDecl->hasMutableFields()) {
data().HasMutableFields = true;
@@ -950,7 +953,7 @@
// Structs with __weak fields should never be passed directly.
if (LT == Qualifiers::OCL_Weak)
- setCanPassInRegisters(false);
+ setCannotPassInRegisters(true);
Data.HasIrrelevantDestructor = false;
} else if (!Context.getLangOpts().ObjCAutoRefCount) {
@@ -1117,6 +1120,8 @@
setHasObjectMember(true);
if (FieldRec->hasVolatileMember())
setHasVolatileMember(true);
+ if (FieldRec->cannotPassInRegisters())
+ setCannotPassInRegisters(true);
// C++0x [class]p7:
// A standard-layout class is a class that:
Index: lib/AST/ASTImporter.cpp
===================================================================
--- lib/AST/ASTImporter.cpp
+++ lib/AST/ASTImporter.cpp
@@ -1108,6 +1108,7 @@
= FromData.HasConstexprNonCopyMoveConstructor;
ToData.HasDefaultedDefaultConstructor
= FromData.HasDefaultedDefaultConstructor;
+ ToData.CannotPassInRegisters = FromData.CannotPassInRegisters;
ToData.DefaultedDefaultConstructorIsConstexpr
= FromData.DefaultedDefaultConstructorIsConstexpr;
ToData.HasConstexprDefaultConstructor
Index: include/clang/AST/DeclCXX.h
===================================================================
--- include/clang/AST/DeclCXX.h
+++ include/clang/AST/DeclCXX.h
@@ -479,6 +479,12 @@
/// constructor.
unsigned HasDefaultedDefaultConstructor : 1;
+ /// Indicates that this class can never be passed or returned in registers.
+ /// This flag is set to true only when this class or one of its subobjects
+ /// has a field (e.g., ObjC __weak pointer field) that makes it impossible
+ /// for this class to be passed in registers.
+ unsigned CannotPassInRegisters : 1;
+
/// \brief True if a defaulted default constructor for this class would
/// be constexpr.
unsigned DefaultedDefaultConstructorIsConstexpr : 1;
@@ -1490,6 +1496,15 @@
return data().HasIrrelevantDestructor;
}
+ /// Indicates that this class can never be passed or returned in registers.
+ bool cannotPassInRegisters() const {
+ return data().CannotPassInRegisters;
+ }
+
+ void setCannotPassInRegisters(bool CannotPass) {
+ data().CannotPassInRegisters = CannotPass;
+ }
+
/// \brief Determine whether this class has a non-literal or/ volatile type
/// non-static data member or base class.
bool hasNonLiteralTypeFieldsOrBases() const {
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