[modules] D29951: Load lazily the template specialization in multi-module setups.
Currently, we load all template specialization if we have more than one module
attached and we touch anything around the template definition.
This patch registers the template specializations as lazily-loadable entities.
In some TUs it reduces the amount of deserializations by 1%.
llvm-svn: 305120
diff --git a/clang/lib/Serialization/ASTReaderDecl.cpp b/clang/lib/Serialization/ASTReaderDecl.cpp
index ed103e62..9c46705 100644
--- a/clang/lib/Serialization/ASTReaderDecl.cpp
+++ b/clang/lib/Serialization/ASTReaderDecl.cpp
@@ -216,6 +216,30 @@
TypedefNameForLinkage(nullptr), HasPendingBody(false),
IsDeclMarkedUsed(false) {}
+ template <typename T> static
+ void AddLazySpecializations(T *D,
+ SmallVectorImpl<serialization::DeclID>& IDs) {
+ if (IDs.empty())
+ return;
+
+ // FIXME: We should avoid this pattern of getting the ASTContext.
+ ASTContext &C = D->getASTContext();
+
+ auto *&LazySpecializations = D->getCommonPtr()->LazySpecializations;
+
+ if (auto &Old = LazySpecializations) {
+ IDs.insert(IDs.end(), Old + 1, Old + 1 + Old[0]);
+ std::sort(IDs.begin(), IDs.end());
+ IDs.erase(std::unique(IDs.begin(), IDs.end()), IDs.end());
+ }
+
+ auto *Result = new (C) serialization::DeclID[1 + IDs.size()];
+ *Result = IDs.size();
+ std::copy(IDs.begin(), IDs.end(), Result + 1);
+
+ LazySpecializations = Result;
+ }
+
template <typename DeclT>
static Decl *getMostRecentDeclImpl(Redeclarable<DeclT> *D);
static Decl *getMostRecentDeclImpl(...);
@@ -244,7 +268,7 @@
void ReadFunctionDefinition(FunctionDecl *FD);
void Visit(Decl *D);
- void UpdateDecl(Decl *D);
+ void UpdateDecl(Decl *D, llvm::SmallVectorImpl<serialization::DeclID>&);
static void setNextObjCCategory(ObjCCategoryDecl *Cat,
ObjCCategoryDecl *Next) {
@@ -1952,21 +1976,6 @@
return Redecl;
}
-static DeclID *newDeclIDList(ASTContext &Context, DeclID *Old,
- SmallVectorImpl<DeclID> &IDs) {
- assert(!IDs.empty() && "no IDs to add to list");
- if (Old) {
- IDs.insert(IDs.end(), Old + 1, Old + 1 + Old[0]);
- std::sort(IDs.begin(), IDs.end());
- IDs.erase(std::unique(IDs.begin(), IDs.end()), IDs.end());
- }
-
- auto *Result = new (Context) DeclID[1 + IDs.size()];
- *Result = IDs.size();
- std::copy(IDs.begin(), IDs.end(), Result + 1);
- return Result;
-}
-
void ASTDeclReader::VisitClassTemplateDecl(ClassTemplateDecl *D) {
RedeclarableResult Redecl = VisitRedeclarableTemplateDecl(D);
@@ -1975,12 +1984,7 @@
// the specializations.
SmallVector<serialization::DeclID, 32> SpecIDs;
ReadDeclIDList(SpecIDs);
-
- if (!SpecIDs.empty()) {
- auto *CommonPtr = D->getCommonPtr();
- CommonPtr->LazySpecializations = newDeclIDList(
- Reader.getContext(), CommonPtr->LazySpecializations, SpecIDs);
- }
+ ASTDeclReader::AddLazySpecializations(D, SpecIDs);
}
if (D->getTemplatedDecl()->TemplateOrInstantiation) {
@@ -2007,12 +2011,7 @@
// the specializations.
SmallVector<serialization::DeclID, 32> SpecIDs;
ReadDeclIDList(SpecIDs);
-
- if (!SpecIDs.empty()) {
- auto *CommonPtr = D->getCommonPtr();
- CommonPtr->LazySpecializations = newDeclIDList(
- Reader.getContext(), CommonPtr->LazySpecializations, SpecIDs);
- }
+ ASTDeclReader::AddLazySpecializations(D, SpecIDs);
}
}
@@ -2118,12 +2117,7 @@
// This FunctionTemplateDecl owns a CommonPtr; read it.
SmallVector<serialization::DeclID, 32> SpecIDs;
ReadDeclIDList(SpecIDs);
-
- if (!SpecIDs.empty()) {
- auto *CommonPtr = D->getCommonPtr();
- CommonPtr->LazySpecializations = newDeclIDList(
- Reader.getContext(), CommonPtr->LazySpecializations, SpecIDs);
- }
+ ASTDeclReader::AddLazySpecializations(D, SpecIDs);
}
}
@@ -3667,6 +3661,9 @@
Decl *D = Record.D;
ProcessingUpdatesRAIIObj ProcessingUpdates(*this);
DeclUpdateOffsetsMap::iterator UpdI = DeclUpdateOffsets.find(ID);
+
+ llvm::SmallVector<serialization::DeclID, 8> PendingLazySpecializationIDs;
+
if (UpdI != DeclUpdateOffsets.end()) {
auto UpdateOffsets = std::move(UpdI->second);
DeclUpdateOffsets.erase(UpdI);
@@ -3691,7 +3688,7 @@
ASTDeclReader Reader(*this, Record, RecordLocation(F, Offset), ID,
SourceLocation());
- Reader.UpdateDecl(D);
+ Reader.UpdateDecl(D, PendingLazySpecializationIDs);
// We might have made this declaration interesting. If so, remember that
// we need to hand it off to the consumer.
@@ -3703,6 +3700,17 @@
}
}
}
+ // Add the lazy specializations to the template.
+ assert((PendingLazySpecializationIDs.empty() || isa<ClassTemplateDecl>(D) ||
+ isa<FunctionTemplateDecl>(D) || isa<VarTemplateDecl>(D)) &&
+ "Must not have pending specializations");
+ if (auto *CTD = dyn_cast<ClassTemplateDecl>(D))
+ ASTDeclReader::AddLazySpecializations(CTD, PendingLazySpecializationIDs);
+ else if (auto *FTD = dyn_cast<FunctionTemplateDecl>(D))
+ ASTDeclReader::AddLazySpecializations(FTD, PendingLazySpecializationIDs);
+ else if (auto *VTD = dyn_cast<VarTemplateDecl>(D))
+ ASTDeclReader::AddLazySpecializations(VTD, PendingLazySpecializationIDs);
+ PendingLazySpecializationIDs.clear();
// Load the pending visible updates for this decl context, if it has any.
auto I = PendingVisibleUpdates.find(ID);
@@ -3899,7 +3907,8 @@
}
}
-void ASTDeclReader::UpdateDecl(Decl *D) {
+void ASTDeclReader::UpdateDecl(Decl *D,
+ llvm::SmallVectorImpl<serialization::DeclID> &PendingLazySpecializationIDs) {
while (Record.getIdx() < Record.size()) {
switch ((DeclUpdateKind)Record.readInt()) {
case UPD_CXX_ADDED_IMPLICIT_MEMBER: {
@@ -3915,8 +3924,8 @@
}
case UPD_CXX_ADDED_TEMPLATE_SPECIALIZATION:
- // It will be added to the template's specializations set when loaded.
- (void)Record.readDecl();
+ // It will be added to the template's lazy specialization set.
+ PendingLazySpecializationIDs.push_back(ReadDeclID());
break;
case UPD_CXX_ADDED_ANONYMOUS_NAMESPACE: {