[PATCH] D50643: [AST] Pack the bits of TemplateSpecializationType into Type
This revision was automatically updated to reflect the committed changes.
Closed by commit rL339787: [AST] Pack the bits of TemplateSpecializationType
into Type (authored by brunoricci, committed by ).
Herald added a subscriber: llvm-commits.
Changed prior to commit:
https://reviews.llvm.org/D50643?vs=160805=160828#toc
Repository:
rL LLVM
https://reviews.llvm.org/D50643
Files:
cfe/trunk/include/clang/AST/Type.h
cfe/trunk/lib/AST/Type.cpp
Index: cfe/trunk/lib/AST/Type.cpp
===
--- cfe/trunk/lib/AST/Type.cpp
+++ cfe/trunk/lib/AST/Type.cpp
@@ -3335,8 +3335,10 @@
Canon.isNull()? true : Canon->isDependentType(),
Canon.isNull()? true : Canon->isInstantiationDependentType(),
false,
- T.containsUnexpandedParameterPack()),
-Template(T), NumArgs(Args.size()), TypeAlias(!AliasedType.isNull()) {
+ T.containsUnexpandedParameterPack()), Template(T) {
+ TemplateSpecializationTypeBits.NumArgs = Args.size();
+ TemplateSpecializationTypeBits.TypeAlias = !AliasedType.isNull();
+
assert(!T.getAsDependentTemplateName() &&
"Use DependentTemplateSpecializationType for dependent template-name");
assert((T.getKind() == TemplateName::Template ||
@@ -3365,7 +3367,7 @@
}
// Store the aliased type if this is a type alias template specialization.
- if (TypeAlias) {
+ if (isTypeAlias()) {
auto *Begin = reinterpret_cast(this + 1);
*reinterpret_cast(Begin + getNumArgs()) = AliasedType;
}
Index: cfe/trunk/include/clang/AST/Type.h
===
--- cfe/trunk/include/clang/AST/Type.h
+++ cfe/trunk/include/clang/AST/Type.h
@@ -1606,6 +1606,24 @@
unsigned Keyword : 2;
};
+ class TemplateSpecializationTypeBitfields {
+friend class TemplateSpecializationType;
+
+unsigned : NumTypeBits;
+
+/// Whether this template specialization type is a substituted type alias.
+unsigned TypeAlias : 1;
+
+/// The number of template arguments named in this class template
+/// specialization, which is expected to be able to hold at least 1024
+/// according to [implimits]. However, as this limit is somewhat easy to
+/// hit with template metaprogramming we'd prefer to keep it as large
+/// as possible. At the moment it has been left as a non-bitfield since
+/// this type safely fits in 64 bits as an unsigned, so there is no reason
+/// to introduce the performance impact of a bitfield.
+unsigned NumArgs;
+ };
+
union {
TypeBitfields TypeBits;
ArrayTypeBitfields ArrayTypeBits;
@@ -1617,6 +1635,7 @@
ReferenceTypeBitfields ReferenceTypeBits;
TypeWithKeywordBitfields TypeWithKeywordBits;
VectorTypeBitfields VectorTypeBits;
+TemplateSpecializationTypeBitfields TemplateSpecializationTypeBits;
static_assert(sizeof(TypeBitfields) <= 8,
"TypeBitfields is larger than 8 bytes!");
@@ -1638,6 +1657,9 @@
"TypeWithKeywordBitfields is larger than 8 bytes!");
static_assert(sizeof(VectorTypeBitfields) <= 8,
"VectorTypeBitfields is larger than 8 bytes!");
+static_assert(sizeof(TemplateSpecializationTypeBitfields) <= 8,
+ "TemplateSpecializationTypeBitfields is larger"
+ " than 8 bytes!");
};
private:
@@ -4669,13 +4691,6 @@
/// replacement must, recursively, be one of these).
TemplateName Template;
- /// The number of template arguments named in this class template
- /// specialization.
- unsigned NumArgs : 31;
-
- /// Whether this template specialization type is a substituted type alias.
- unsigned TypeAlias : 1;
-
TemplateSpecializationType(TemplateName T,
ArrayRef Args,
QualType Canon,
@@ -4710,7 +4725,7 @@
/// typedef A type; // not a type alias
/// };
/// \endcode
- bool isTypeAlias() const { return TypeAlias; }
+ bool isTypeAlias() const { return TemplateSpecializationTypeBits.TypeAlias; }
/// Get the aliased type, if this is a specialization of a type alias
/// template.
@@ -4733,14 +4748,16 @@
}
/// Retrieve the number of template arguments.
- unsigned getNumArgs() const { return NumArgs; }
+ unsigned getNumArgs() const {
+return TemplateSpecializationTypeBits.NumArgs;
+ }
/// Retrieve a specific template argument as a type.
/// \pre \c isArgType(Arg)
const TemplateArgument (unsigned Idx) const; // in TemplateBase.h
ArrayRef template_arguments() const {
-return {getArgs(), NumArgs};
+return {getArgs(), getNumArgs()};
}
bool isSugared() const {
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[PATCH] D50643: [AST] Pack the bits of TemplateSpecializationType into Type
riccibruno updated this revision to Diff 160805.
riccibruno added a comment.
update the comment in TemplateSpecializationTypeBitfields
Repository:
rC Clang
https://reviews.llvm.org/D50643
Files:
include/clang/AST/Type.h
lib/AST/Type.cpp
Index: lib/AST/Type.cpp
===
--- lib/AST/Type.cpp
+++ lib/AST/Type.cpp
@@ -3335,8 +3335,10 @@
Canon.isNull()? true : Canon->isDependentType(),
Canon.isNull()? true : Canon->isInstantiationDependentType(),
false,
- T.containsUnexpandedParameterPack()),
-Template(T), NumArgs(Args.size()), TypeAlias(!AliasedType.isNull()) {
+ T.containsUnexpandedParameterPack()), Template(T) {
+ TemplateSpecializationTypeBits.NumArgs = Args.size();
+ TemplateSpecializationTypeBits.TypeAlias = !AliasedType.isNull();
+
assert(!T.getAsDependentTemplateName() &&
"Use DependentTemplateSpecializationType for dependent template-name");
assert((T.getKind() == TemplateName::Template ||
@@ -3365,7 +3367,7 @@
}
// Store the aliased type if this is a type alias template specialization.
- if (TypeAlias) {
+ if (isTypeAlias()) {
auto *Begin = reinterpret_cast(this + 1);
*reinterpret_cast(Begin + getNumArgs()) = AliasedType;
}
Index: include/clang/AST/Type.h
===
--- include/clang/AST/Type.h
+++ include/clang/AST/Type.h
@@ -1624,6 +1624,24 @@
unsigned Keyword : 2;
};
+ class TemplateSpecializationTypeBitfields {
+friend class TemplateSpecializationType;
+
+unsigned : NumTypeBits;
+
+/// Whether this template specialization type is a substituted type alias.
+unsigned TypeAlias : 1;
+
+/// The number of template arguments named in this class template
+/// specialization, which is expected to be able to hold at least 1024
+/// according to [implimits]. However, as this limit is somewhat easy to
+/// hit with template metaprogramming we'd prefer to keep it as large
+/// as possible. At the moment it has been left as a non-bitfield since
+/// this type safely fits in 64 bits as an unsigned, so there is no reason
+/// to introduce the performance impact of a bitfield.
+unsigned NumArgs;
+ };
+
union {
TypeBitfields TypeBits;
ArrayTypeBitfields ArrayTypeBits;
@@ -1635,6 +1653,7 @@
ReferenceTypeBitfields ReferenceTypeBits;
TypeWithKeywordBitfields TypeWithKeywordBits;
VectorTypeBitfields VectorTypeBits;
+TemplateSpecializationTypeBitfields TemplateSpecializationTypeBits;
static_assert(sizeof(TypeBitfields) <= 8,
"TypeBitfields is larger than 8 bytes!");
@@ -1656,6 +1675,9 @@
"TypeWithKeywordBitfields is larger than 8 bytes!");
static_assert(sizeof(VectorTypeBitfields) <= 8,
"VectorTypeBitfields is larger than 8 bytes!");
+static_assert(sizeof(TemplateSpecializationTypeBitfields) <= 8,
+ "TemplateSpecializationTypeBitfields is larger"
+ " than 8 bytes!");
};
private:
@@ -4673,13 +4695,6 @@
/// replacement must, recursively, be one of these).
TemplateName Template;
- /// The number of template arguments named in this class template
- /// specialization.
- unsigned NumArgs : 31;
-
- /// Whether this template specialization type is a substituted type alias.
- unsigned TypeAlias : 1;
-
TemplateSpecializationType(TemplateName T,
ArrayRef Args,
QualType Canon,
@@ -4714,7 +4729,7 @@
/// typedef A type; // not a type alias
/// };
/// \endcode
- bool isTypeAlias() const { return TypeAlias; }
+ bool isTypeAlias() const { return TemplateSpecializationTypeBits.TypeAlias; }
/// Get the aliased type, if this is a specialization of a type alias
/// template.
@@ -4737,14 +4752,16 @@
}
/// Retrieve the number of template arguments.
- unsigned getNumArgs() const { return NumArgs; }
+ unsigned getNumArgs() const {
+return TemplateSpecializationTypeBits.NumArgs;
+ }
/// Retrieve a specific template argument as a type.
/// \pre \c isArgType(Arg)
const TemplateArgument (unsigned Idx) const; // in TemplateBase.h
ArrayRef template_arguments() const {
-return {getArgs(), NumArgs};
+return {getArgs(), getNumArgs()};
}
bool isSugared() const {
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[PATCH] D50643: [AST] Pack the bits of TemplateSpecializationType into Type
riccibruno added a comment. I don't like these bit-field abuses too much but this is used all over the place in clang and so if this breaks so many things are going to break. Repository: rC Clang https://reviews.llvm.org/D50643 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D50643: [AST] Pack the bits of TemplateSpecializationType into Type
erichkeane accepted this revision. erichkeane added a comment. This revision is now accepted and ready to land. Ah, right. I missed that the others already do it. Fine I guess... Repository: rC Clang https://reviews.llvm.org/D50643 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D50643: [AST] Pack the bits of TemplateSpecializationType into Type
riccibruno added a comment. All of these bitfields (ab)use are already UB I think... I don't see what is special in this case... Repository: rC Clang https://reviews.llvm.org/D50643 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D50643: [AST] Pack the bits of TemplateSpecializationType into Type
erichkeane added a comment. I think that this causes UB. The Type baseclass will use the TypeBitfields active member, but this uses the TemplateSpecializationTypeBits, right? I know we take advantage of this elsewhere, but I'm tentative about this one... Repository: rC Clang https://reviews.llvm.org/D50643 ___ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
[PATCH] D50643: [AST] Pack the bits of TemplateSpecializationType into Type
riccibruno created this revision.
riccibruno added a reviewer: erichkeane.
riccibruno added a project: clang.
Herald added a subscriber: cfe-commits.
Type has enough space for two members of
TemplateSpecializationType. Mechanical patch.
Repository:
rC Clang
https://reviews.llvm.org/D50643
Files:
include/clang/AST/Type.h
lib/AST/Type.cpp
Index: lib/AST/Type.cpp
===
--- lib/AST/Type.cpp
+++ lib/AST/Type.cpp
@@ -3335,8 +3335,10 @@
Canon.isNull()? true : Canon->isDependentType(),
Canon.isNull()? true : Canon->isInstantiationDependentType(),
false,
- T.containsUnexpandedParameterPack()),
-Template(T), NumArgs(Args.size()), TypeAlias(!AliasedType.isNull()) {
+ T.containsUnexpandedParameterPack()), Template(T) {
+ TemplateSpecializationTypeBits.NumArgs = Args.size();
+ TemplateSpecializationTypeBits.TypeAlias = !AliasedType.isNull();
+
assert(!T.getAsDependentTemplateName() &&
"Use DependentTemplateSpecializationType for dependent template-name");
assert((T.getKind() == TemplateName::Template ||
@@ -3365,7 +3367,7 @@
}
// Store the aliased type if this is a type alias template specialization.
- if (TypeAlias) {
+ if (isTypeAlias()) {
auto *Begin = reinterpret_cast(this + 1);
*reinterpret_cast(Begin + getNumArgs()) = AliasedType;
}
Index: include/clang/AST/Type.h
===
--- include/clang/AST/Type.h
+++ include/clang/AST/Type.h
@@ -1624,6 +1624,20 @@
unsigned Keyword : 2;
};
+ class TemplateSpecializationTypeBitfields {
+friend class TemplateSpecializationType;
+
+unsigned : NumTypeBits;
+
+/// Whether this template specialization type is a substituted type alias.
+unsigned TypeAlias : 1;
+
+/// The number of template arguments named in this class template
+/// specialization. Intentionally not a bitfield since we have
+/// plenty of space left.
+unsigned NumArgs;
+ };
+
union {
TypeBitfields TypeBits;
ArrayTypeBitfields ArrayTypeBits;
@@ -1635,6 +1649,7 @@
ReferenceTypeBitfields ReferenceTypeBits;
TypeWithKeywordBitfields TypeWithKeywordBits;
VectorTypeBitfields VectorTypeBits;
+TemplateSpecializationTypeBitfields TemplateSpecializationTypeBits;
static_assert(sizeof(TypeBitfields) <= 8,
"TypeBitfields is larger than 8 bytes!");
@@ -1656,6 +1671,9 @@
"TypeWithKeywordBitfields is larger than 8 bytes!");
static_assert(sizeof(VectorTypeBitfields) <= 8,
"VectorTypeBitfields is larger than 8 bytes!");
+static_assert(sizeof(TemplateSpecializationTypeBitfields) <= 8,
+ "TemplateSpecializationTypeBitfields is larger"
+ " than 8 bytes!");
};
private:
@@ -4673,13 +4691,6 @@
/// replacement must, recursively, be one of these).
TemplateName Template;
- /// The number of template arguments named in this class template
- /// specialization.
- unsigned NumArgs : 31;
-
- /// Whether this template specialization type is a substituted type alias.
- unsigned TypeAlias : 1;
-
TemplateSpecializationType(TemplateName T,
ArrayRef Args,
QualType Canon,
@@ -4714,7 +4725,7 @@
/// typedef A type; // not a type alias
/// };
/// \endcode
- bool isTypeAlias() const { return TypeAlias; }
+ bool isTypeAlias() const { return TemplateSpecializationTypeBits.TypeAlias; }
/// Get the aliased type, if this is a specialization of a type alias
/// template.
@@ -4737,14 +4748,16 @@
}
/// Retrieve the number of template arguments.
- unsigned getNumArgs() const { return NumArgs; }
+ unsigned getNumArgs() const {
+return TemplateSpecializationTypeBits.NumArgs;
+ }
/// Retrieve a specific template argument as a type.
/// \pre \c isArgType(Arg)
const TemplateArgument (unsigned Idx) const; // in TemplateBase.h
ArrayRef template_arguments() const {
-return {getArgs(), NumArgs};
+return {getArgs(), getNumArgs()};
}
bool isSugared() const {
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