r274316 - [Feature] Add a builtin for indexing into parameter packs. Patch by Louis Dionne.
Eric Fiselier via cfe-commits
cfe-commits at lists.llvm.org
Thu Jun 30 18:24:09 PDT 2016
Author: ericwf
Date: Thu Jun 30 20:24:09 2016
New Revision: 274316
URL: http://llvm.org/viewvc/llvm-project?rev=274316&view=rev
Log:
[Feature] Add a builtin for indexing into parameter packs. Patch by Louis Dionne.
This patch adds a __nth_element builtin that allows fetching the n-th type of a
parameter pack with very little compile-time overhead. The patch was inspired by
r252036 and r252115 by David Majnemer, which add a similar __make_integer_seq
builtin for efficiently creating a std::integer_sequence.
Reviewed as D15421. http://reviews.llvm.org/D15421
Added:
cfe/trunk/test/PCH/type_pack_element.cpp
cfe/trunk/test/SemaCXX/type_pack_element.cpp
Modified:
cfe/trunk/include/clang/AST/ASTContext.h
cfe/trunk/include/clang/AST/DeclTemplate.h
cfe/trunk/include/clang/Basic/Builtins.h
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/include/clang/Serialization/ASTBitCodes.h
cfe/trunk/lib/AST/ASTContext.cpp
cfe/trunk/lib/AST/DeclTemplate.cpp
cfe/trunk/lib/Lex/PPMacroExpansion.cpp
cfe/trunk/lib/Sema/SemaLookup.cpp
cfe/trunk/lib/Sema/SemaTemplate.cpp
cfe/trunk/lib/Serialization/ASTReader.cpp
cfe/trunk/lib/Serialization/ASTWriter.cpp
Modified: cfe/trunk/include/clang/AST/ASTContext.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ASTContext.h?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/ASTContext.h (original)
+++ cfe/trunk/include/clang/AST/ASTContext.h Thu Jun 30 20:24:09 2016
@@ -255,6 +255,9 @@ class ASTContext : public RefCountedBase
/// The identifier '__make_integer_seq'.
mutable IdentifierInfo *MakeIntegerSeqName = nullptr;
+ /// The identifier '__type_pack_element'.
+ mutable IdentifierInfo *TypePackElementName = nullptr;
+
QualType ObjCConstantStringType;
mutable RecordDecl *CFConstantStringTagDecl;
mutable TypedefDecl *CFConstantStringTypeDecl;
@@ -410,6 +413,7 @@ private:
TranslationUnitDecl *TUDecl;
mutable ExternCContextDecl *ExternCContext;
mutable BuiltinTemplateDecl *MakeIntegerSeqDecl;
+ mutable BuiltinTemplateDecl *TypePackElementDecl;
/// \brief The associated SourceManager object.a
SourceManager &SourceMgr;
@@ -880,6 +884,7 @@ public:
ExternCContextDecl *getExternCContextDecl() const;
BuiltinTemplateDecl *getMakeIntegerSeqDecl() const;
+ BuiltinTemplateDecl *getTypePackElementDecl() const;
// Builtin Types.
CanQualType VoidTy;
@@ -1473,6 +1478,12 @@ public:
return MakeIntegerSeqName;
}
+ IdentifierInfo *getTypePackElementName() const {
+ if (!TypePackElementName)
+ TypePackElementName = &Idents.get("__type_pack_element");
+ return TypePackElementName;
+ }
+
/// \brief Retrieve the Objective-C "instancetype" type, if already known;
/// otherwise, returns a NULL type;
QualType getObjCInstanceType() {
Modified: cfe/trunk/include/clang/AST/DeclTemplate.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/DeclTemplate.h?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/include/clang/AST/DeclTemplate.h (original)
+++ cfe/trunk/include/clang/AST/DeclTemplate.h Thu Jun 30 20:24:09 2016
@@ -1490,8 +1490,8 @@ public:
};
/// \brief Represents the builtin template declaration which is used to
-/// implement __make_integer_seq. It serves no real purpose beyond existing as
-/// a place to hold template parameters.
+/// implement __make_integer_seq and other builtin templates. It serves
+/// no real purpose beyond existing as a place to hold template parameters.
class BuiltinTemplateDecl : public TemplateDecl {
void anchor() override;
Modified: cfe/trunk/include/clang/Basic/Builtins.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Builtins.h?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/Builtins.h (original)
+++ cfe/trunk/include/clang/Basic/Builtins.h Thu Jun 30 20:24:09 2016
@@ -219,7 +219,10 @@ private:
/// \brief Kinds of BuiltinTemplateDecl.
enum BuiltinTemplateKind : int {
/// \brief This names the __make_integer_seq BuiltinTemplateDecl.
- BTK__make_integer_seq
+ BTK__make_integer_seq,
+
+ /// \brief This names the __type_pack_element BuiltinTemplateDecl.
+ BTK__type_pack_element
};
} // end namespace clang
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Jun 30 20:24:09 2016
@@ -2128,6 +2128,10 @@ def err_integer_sequence_negative_length
def err_integer_sequence_integral_element_type : Error<
"integer sequences must have integral element type">;
+// __type_pack_element
+def err_type_pack_element_out_of_bounds : Error<
+ "a parameter pack may not be accessed at an out of bounds index">;
+
// Objective-C++
def err_objc_decls_may_only_appear_in_global_scope : Error<
"Objective-C declarations may only appear in global scope">;
Modified: cfe/trunk/include/clang/Serialization/ASTBitCodes.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Serialization/ASTBitCodes.h?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/include/clang/Serialization/ASTBitCodes.h (original)
+++ cfe/trunk/include/clang/Serialization/ASTBitCodes.h Thu Jun 30 20:24:09 2016
@@ -983,13 +983,16 @@ namespace clang {
/// \brief The internal '__NSConstantString' tag type.
PREDEF_DECL_CF_CONSTANT_STRING_TAG_ID = 15,
+
+ /// \brief The internal '__type_pack_element' template.
+ PREDEF_DECL_TYPE_PACK_ELEMENT_ID = 16,
};
/// \brief The number of declaration IDs that are predefined.
///
/// For more information about predefined declarations, see the
/// \c PredefinedDeclIDs type and the PREDEF_DECL_*_ID constants.
- const unsigned int NUM_PREDEF_DECL_IDS = 16;
+ const unsigned int NUM_PREDEF_DECL_IDS = 17;
/// \brief Record of updates for a declaration that was modified after
/// being deserialized. This can occur within DECLTYPES_BLOCK_ID.
Modified: cfe/trunk/lib/AST/ASTContext.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ASTContext.cpp (original)
+++ cfe/trunk/lib/AST/ASTContext.cpp Thu Jun 30 20:24:09 2016
@@ -742,8 +742,8 @@ ASTContext::ASTContext(LangOptions &LOpt
sigjmp_bufDecl(nullptr), ucontext_tDecl(nullptr),
BlockDescriptorType(nullptr), BlockDescriptorExtendedType(nullptr),
cudaConfigureCallDecl(nullptr), FirstLocalImport(), LastLocalImport(),
- ExternCContext(nullptr), MakeIntegerSeqDecl(nullptr), SourceMgr(SM),
- LangOpts(LOpts),
+ ExternCContext(nullptr), MakeIntegerSeqDecl(nullptr),
+ TypePackElementDecl(nullptr), SourceMgr(SM), LangOpts(LOpts),
SanitizerBL(new SanitizerBlacklist(LangOpts.SanitizerBlacklistFiles, SM)),
AddrSpaceMap(nullptr), Target(nullptr), AuxTarget(nullptr),
PrintingPolicy(LOpts), Idents(idents), Selectors(sels),
@@ -928,6 +928,14 @@ ASTContext::getMakeIntegerSeqDecl() cons
return MakeIntegerSeqDecl;
}
+BuiltinTemplateDecl *
+ASTContext::getTypePackElementDecl() const {
+ if (!TypePackElementDecl)
+ TypePackElementDecl = buildBuiltinTemplateDecl(BTK__type_pack_element,
+ getTypePackElementName());
+ return TypePackElementDecl;
+}
+
RecordDecl *ASTContext::buildImplicitRecord(StringRef Name,
RecordDecl::TagKind TK) const {
SourceLocation Loc;
Modified: cfe/trunk/lib/AST/DeclTemplate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/DeclTemplate.cpp?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/lib/AST/DeclTemplate.cpp (original)
+++ cfe/trunk/lib/AST/DeclTemplate.cpp Thu Jun 30 20:24:09 2016
@@ -1239,11 +1239,34 @@ createMakeIntegerSeqParameterList(const
Params, SourceLocation());
}
+static TemplateParameterList *
+createTypePackElementParameterList(const ASTContext &C, DeclContext *DC) {
+ // std::size_t Index
+ TypeSourceInfo *TInfo = C.getTrivialTypeSourceInfo(C.getSizeType());
+ auto *Index = NonTypeTemplateParmDecl::Create(
+ C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/0,
+ /*Id=*/nullptr, TInfo->getType(), /*ParameterPack=*/false, TInfo);
+
+ // typename ...T
+ auto *Ts = TemplateTypeParmDecl::Create(
+ C, DC, SourceLocation(), SourceLocation(), /*Depth=*/0, /*Position=*/1,
+ /*Id=*/nullptr, /*Typename=*/true, /*ParameterPack=*/true);
+ Ts->setImplicit(true);
+
+ // template <std::size_t Index, typename ...T>
+ NamedDecl *Params[] = {Index, Ts};
+ return TemplateParameterList::Create(C, SourceLocation(), SourceLocation(),
+ llvm::makeArrayRef(Params),
+ SourceLocation());
+}
+
static TemplateParameterList *createBuiltinTemplateParameterList(
const ASTContext &C, DeclContext *DC, BuiltinTemplateKind BTK) {
switch (BTK) {
case BTK__make_integer_seq:
return createMakeIntegerSeqParameterList(C, DC);
+ case BTK__type_pack_element:
+ return createTypePackElementParameterList(C, DC);
}
llvm_unreachable("unhandled BuiltinTemplateKind!");
Modified: cfe/trunk/lib/Lex/PPMacroExpansion.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Lex/PPMacroExpansion.cpp?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/lib/Lex/PPMacroExpansion.cpp (original)
+++ cfe/trunk/lib/Lex/PPMacroExpansion.cpp Thu Jun 30 20:24:09 2016
@@ -1695,6 +1695,7 @@ void Preprocessor::ExpandBuiltinMacro(To
const LangOptions &LangOpts = getLangOpts();
return llvm::StringSwitch<bool>(II->getName())
.Case("__make_integer_seq", LangOpts.CPlusPlus)
+ .Case("__type_pack_element", LangOpts.CPlusPlus)
.Default(false);
}
});
Modified: cfe/trunk/lib/Sema/SemaLookup.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLookup.cpp?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaLookup.cpp (original)
+++ cfe/trunk/lib/Sema/SemaLookup.cpp Thu Jun 30 20:24:09 2016
@@ -680,10 +680,14 @@ static bool LookupBuiltin(Sema &S, Looku
NameKind == Sema::LookupRedeclarationWithLinkage) {
IdentifierInfo *II = R.getLookupName().getAsIdentifierInfo();
if (II) {
- if (S.getLangOpts().CPlusPlus && NameKind == Sema::LookupOrdinaryName &&
- II == S.getASTContext().getMakeIntegerSeqName()) {
- R.addDecl(S.getASTContext().getMakeIntegerSeqDecl());
- return true;
+ if (S.getLangOpts().CPlusPlus && NameKind == Sema::LookupOrdinaryName) {
+ if (II == S.getASTContext().getMakeIntegerSeqName()) {
+ R.addDecl(S.getASTContext().getMakeIntegerSeqDecl());
+ return true;
+ } else if (II == S.getASTContext().getTypePackElementName()) {
+ R.addDecl(S.getASTContext().getTypePackElementDecl());
+ return true;
+ }
}
// If this is a builtin on this (or all) targets, create the decl.
Modified: cfe/trunk/lib/Sema/SemaTemplate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaTemplate.cpp?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaTemplate.cpp (original)
+++ cfe/trunk/lib/Sema/SemaTemplate.cpp Thu Jun 30 20:24:09 2016
@@ -33,6 +33,7 @@
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringExtras.h"
+#include <iterator>
using namespace clang;
using namespace sema;
@@ -2042,7 +2043,7 @@ checkBuiltinTemplateIdType(Sema &SemaRef
TemplateArgumentListInfo &TemplateArgs) {
ASTContext &Context = SemaRef.getASTContext();
switch (BTD->getBuiltinTemplateKind()) {
- case BTK__make_integer_seq:
+ case BTK__make_integer_seq: {
// Specializations of __make_integer_seq<S, T, N> are treated like
// S<T, 0, ..., N-1>.
@@ -2084,6 +2085,29 @@ checkBuiltinTemplateIdType(Sema &SemaRef
return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
TemplateLoc, SyntheticTemplateArgs);
}
+
+ case BTK__type_pack_element:
+ // Specializations of
+ // __type_pack_element<Index, T_1, ..., T_N>
+ // are treated like T_Index.
+ assert(Converted.size() == 2 &&
+ "__type_pack_element should be given an index and a parameter pack");
+
+ // If the Index is out of bounds, the program is ill-formed.
+ TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
+ llvm::APSInt Index = IndexArg.getAsIntegral();
+ assert(Index >= 0 && "the index used with __type_pack_element should be of "
+ "type std::size_t, and hence be non-negative");
+ if (Index >= Ts.pack_size()) {
+ SemaRef.Diag(TemplateArgs[0].getLocation(),
+ diag::err_type_pack_element_out_of_bounds);
+ return QualType();
+ }
+
+ // We simply return the type at index `Index`.
+ auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
+ return Nth->getAsType();
+ }
llvm_unreachable("unexpected BuiltinTemplateDecl!");
}
Modified: cfe/trunk/lib/Serialization/ASTReader.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReader.cpp?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTReader.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTReader.cpp Thu Jun 30 20:24:09 2016
@@ -6428,6 +6428,9 @@ static Decl *getPredefinedDecl(ASTContex
case PREDEF_DECL_CF_CONSTANT_STRING_TAG_ID:
return Context.getCFConstantStringTagDecl();
+
+ case PREDEF_DECL_TYPE_PACK_ELEMENT_ID:
+ return Context.getTypePackElementDecl();
}
llvm_unreachable("PredefinedDeclIDs unknown enum value");
}
Modified: cfe/trunk/lib/Serialization/ASTWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTWriter.cpp?rev=274316&r1=274315&r2=274316&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTWriter.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTWriter.cpp Thu Jun 30 20:24:09 2016
@@ -4191,6 +4191,8 @@ uint64_t ASTWriter::WriteASTCore(Sema &S
PREDEF_DECL_CF_CONSTANT_STRING_ID);
RegisterPredefDecl(Context.CFConstantStringTagDecl,
PREDEF_DECL_CF_CONSTANT_STRING_TAG_ID);
+ RegisterPredefDecl(Context.TypePackElementDecl,
+ PREDEF_DECL_TYPE_PACK_ELEMENT_ID);
// Build a record containing all of the tentative definitions in this file, in
// TentativeDefinitions order. Generally, this record will be empty for
Added: cfe/trunk/test/PCH/type_pack_element.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/PCH/type_pack_element.cpp?rev=274316&view=auto
==============================================================================
--- cfe/trunk/test/PCH/type_pack_element.cpp (added)
+++ cfe/trunk/test/PCH/type_pack_element.cpp Thu Jun 30 20:24:09 2016
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -std=c++14 -x c++-header %s -emit-pch -o %t.pch
+// RUN: %clang_cc1 -std=c++14 -x c++ /dev/null -include-pch %t.pch
+
+template <int i>
+struct X { };
+
+using SizeT = decltype(sizeof(int));
+
+template <SizeT i, typename ...T>
+using TypePackElement = __type_pack_element<i, T...>;
+
+void fn1() {
+ X<0> x0 = TypePackElement<0, X<0>, X<1>, X<2>>{};
+ X<1> x1 = TypePackElement<1, X<0>, X<1>, X<2>>{};
+ X<2> x2 = TypePackElement<2, X<0>, X<1>, X<2>>{};
+}
Added: cfe/trunk/test/SemaCXX/type_pack_element.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/type_pack_element.cpp?rev=274316&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/type_pack_element.cpp (added)
+++ cfe/trunk/test/SemaCXX/type_pack_element.cpp Thu Jun 30 20:24:09 2016
@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+
+static_assert(__has_builtin(__type_pack_element), "");
+
+using SizeT = decltype(sizeof(int));
+
+template <SizeT i, typename ...T>
+using TypePackElement = __type_pack_element<i, T...>;
+
+template <int i>
+struct X;
+
+static_assert(__is_same(TypePackElement<0, X<0>>, X<0>), "");
+
+static_assert(__is_same(TypePackElement<0, X<0>, X<1>>, X<0>), "");
+static_assert(__is_same(TypePackElement<1, X<0>, X<1>>, X<1>), "");
+
+static_assert(__is_same(TypePackElement<0, X<0>, X<1>, X<2>>, X<0>), "");
+static_assert(__is_same(TypePackElement<1, X<0>, X<1>, X<2>>, X<1>), "");
+static_assert(__is_same(TypePackElement<2, X<0>, X<1>, X<2>>, X<2>), "");
+
+static_assert(__is_same(TypePackElement<0, X<0>, X<1>, X<2>, X<3>>, X<0>), "");
+static_assert(__is_same(TypePackElement<1, X<0>, X<1>, X<2>, X<3>>, X<1>), "");
+static_assert(__is_same(TypePackElement<2, X<0>, X<1>, X<2>, X<3>>, X<2>), "");
+static_assert(__is_same(TypePackElement<3, X<0>, X<1>, X<2>, X<3>>, X<3>), "");
+
+static_assert(__is_same(TypePackElement<0, X<0>, X<1>, X<2>, X<3>, X<4>>, X<0>), "");
+static_assert(__is_same(TypePackElement<1, X<0>, X<1>, X<2>, X<3>, X<4>>, X<1>), "");
+static_assert(__is_same(TypePackElement<2, X<0>, X<1>, X<2>, X<3>, X<4>>, X<2>), "");
+static_assert(__is_same(TypePackElement<3, X<0>, X<1>, X<2>, X<3>, X<4>>, X<3>), "");
+static_assert(__is_same(TypePackElement<4, X<0>, X<1>, X<2>, X<3>, X<4>>, X<4>), "");
+
+static_assert(__is_same(TypePackElement<0, X<0>, X<1>, X<2>, X<3>, X<4>, X<5>>, X<0>), "");
+static_assert(__is_same(TypePackElement<1, X<0>, X<1>, X<2>, X<3>, X<4>, X<5>>, X<1>), "");
+static_assert(__is_same(TypePackElement<2, X<0>, X<1>, X<2>, X<3>, X<4>, X<5>>, X<2>), "");
+static_assert(__is_same(TypePackElement<3, X<0>, X<1>, X<2>, X<3>, X<4>, X<5>>, X<3>), "");
+static_assert(__is_same(TypePackElement<4, X<0>, X<1>, X<2>, X<3>, X<4>, X<5>>, X<4>), "");
+static_assert(__is_same(TypePackElement<5, X<0>, X<1>, X<2>, X<3>, X<4>, X<5>>, X<5>), "");
+
+// Test __type_pack_element with more than 2 top-level template arguments.
+static_assert(__is_same(__type_pack_element<5, X<0>, X<1>, X<2>, X<3>, X<4>, X<5>>, X<5>), "");
+
+template <SizeT Index, typename ...T>
+using ErrorTypePackElement1 = __type_pack_element<Index, T...>; // expected-error{{may not be accessed at an out of bounds index}}
+using illformed1 = ErrorTypePackElement1<3, X<0>, X<1>>; // expected-note{{in instantiation}}
More information about the cfe-commits
mailing list