bkramer created this revision.
bkramer added reviewers: klimek, djasper.
bkramer added a subscriber: cfe-commits.
These are by far the most common types to be parents in the AST so it makes
sense to optimize for them. Put them directly into the value of the map.
This currently saves 32 bytes per parent in the map and a pointer
indirection at the cost of some additional complexity in the code.
Sadly this means we cannot return an ArrayRef from getParents anymore, add
a proxy class that can own a single DynTypedNode and otherwise behaves
exactly the same as ArrayRef.
For example on a random large file (X86ISelLowering.cpp) this reduces the size
of the parent map by 24 MB.
http://reviews.llvm.org/D13976
Files:
include/clang/AST/ASTContext.h
lib/AST/ASTContext.cpp
Index: lib/AST/ASTContext.cpp
===================================================================
--- lib/AST/ASTContext.cpp
+++ lib/AST/ASTContext.cpp
@@ -797,8 +797,7 @@
for (const auto &Entry : *AllParents) {
if (Entry.second.is<ast_type_traits::DynTypedNode *>()) {
delete Entry.second.get<ast_type_traits::DynTypedNode *>();
- } else {
- assert(Entry.second.is<ParentVector *>());
+ } else if (Entry.second.is<ParentVector *>()) {
delete Entry.second.get<ParentVector *>();
}
}
@@ -8673,6 +8672,15 @@
namespace {
+ast_type_traits::DynTypedNode
+getSingleDynTypedNodeFromParentMap(ASTContext::ParentMap::mapped_type U) {
+ if (const auto *D = U.template dyn_cast<const Decl *>())
+ return ast_type_traits::DynTypedNode::create(*D);
+ if (const auto *S = U.template dyn_cast<const Stmt *>())
+ return ast_type_traits::DynTypedNode::create(*S);
+ return *U.template get<ast_type_traits::DynTypedNode *>();
+}
+
/// \brief A \c RecursiveASTVisitor that builds a map from nodes to their
/// parents as defined by the \c RecursiveASTVisitor.
///
@@ -8728,16 +8736,23 @@
// do not have pointer identity.
auto &NodeOrVector = (*Parents)[Node];
if (NodeOrVector.isNull()) {
- NodeOrVector = new ast_type_traits::DynTypedNode(ParentStack.back());
+ if (const auto *D = ParentStack.back().get<Decl>())
+ NodeOrVector = D;
+ else if (const auto *S = ParentStack.back().get<Stmt>())
+ NodeOrVector = S;
+ else
+ NodeOrVector =
+ new ast_type_traits::DynTypedNode(ParentStack.back());
} else {
- if (NodeOrVector.template is<ast_type_traits::DynTypedNode *>()) {
- auto *Node =
- NodeOrVector.template get<ast_type_traits::DynTypedNode *>();
- auto *Vector = new ASTContext::ParentVector(1, *Node);
+ if (!NodeOrVector.template is<ASTContext::ParentVector *>()) {
+ auto *Vector = new ASTContext::ParentVector(
+ 1, getSingleDynTypedNodeFromParentMap(NodeOrVector));
NodeOrVector = Vector;
- delete Node;
+ if (auto *Node =
+ NodeOrVector
+ .template dyn_cast<ast_type_traits::DynTypedNode *>())
+ delete Node;
}
- assert(NodeOrVector.template is<ASTContext::ParentVector *>());
auto *Vector =
NodeOrVector.template get<ASTContext::ParentVector *>();
@@ -8774,7 +8789,7 @@
} // end namespace
-ArrayRef<ast_type_traits::DynTypedNode>
+ASTContext::DynTypedNodeList
ASTContext::getParents(const ast_type_traits::DynTypedNode &Node) {
assert(Node.getMemoizationData() &&
"Invariant broken: only nodes that support memoization may be "
@@ -8787,12 +8802,12 @@
}
ParentMap::const_iterator I = AllParents->find(Node.getMemoizationData());
if (I == AllParents->end()) {
- return None;
+ return llvm::ArrayRef<ast_type_traits::DynTypedNode>();
}
- if (auto *N = I->second.dyn_cast<ast_type_traits::DynTypedNode *>()) {
- return llvm::makeArrayRef(N, 1);
+ if (auto *V = I->second.dyn_cast<ParentVector *>()) {
+ return llvm::makeArrayRef(*V);
}
- return *I->second.get<ParentVector *>();
+ return getSingleDynTypedNodeFromParentMap(I->second);
}
bool
Index: include/clang/AST/ASTContext.h
===================================================================
--- include/clang/AST/ASTContext.h
+++ include/clang/AST/ASTContext.h
@@ -453,8 +453,45 @@
/// \brief Maps from a node to its parents.
typedef llvm::DenseMap<const void *,
- llvm::PointerUnion<ast_type_traits::DynTypedNode *,
- ParentVector *>> ParentMap;
+ llvm::PointerUnion4<const Decl *, const Stmt *,
+ ast_type_traits::DynTypedNode *,
+ ParentVector *>> ParentMap;
+
+ /// Container for either a single DynTypedNode or for an ArrayRef to
+ /// DynTypedNode. For use with ParentMap.
+ class DynTypedNodeList {
+ typedef ast_type_traits::DynTypedNode DynTypedNode;
+ typedef ArrayRef<DynTypedNode> ARef;
+ llvm::AlignedCharArrayUnion<ast_type_traits::DynTypedNode, ARef> Storage;
+ bool IsSingleNode;
+
+ public:
+ DynTypedNodeList(const DynTypedNode &N) : IsSingleNode(true) {
+ new (Storage.buffer) DynTypedNode(N);
+ }
+ DynTypedNodeList(ARef A) : IsSingleNode(false) {
+ new (Storage.buffer) ARef(A);
+ }
+
+ const ast_type_traits::DynTypedNode *begin() const {
+ if (!IsSingleNode)
+ return reinterpret_cast<const ARef *>(Storage.buffer)->begin();
+ return reinterpret_cast<const DynTypedNode *>(Storage.buffer);
+ }
+
+ const ast_type_traits::DynTypedNode *end() const {
+ if (!IsSingleNode)
+ return reinterpret_cast<const ARef *>(Storage.buffer)->end();
+ return reinterpret_cast<const DynTypedNode *>(Storage.buffer) + 1;
+ }
+
+ size_t size() const { return end() - begin(); }
+ bool empty() const { return begin() == end(); }
+ const ast_type_traits::DynTypedNode &operator[](size_t N) const {
+ assert(N < size() && "Out of bounds!");
+ return *(begin() + N);
+ }
+ };
/// \brief Returns the parents of the given node.
///
@@ -480,13 +517,11 @@
///
/// 'NodeT' can be one of Decl, Stmt, Type, TypeLoc,
/// NestedNameSpecifier or NestedNameSpecifierLoc.
- template <typename NodeT>
- ArrayRef<ast_type_traits::DynTypedNode> getParents(const NodeT &Node) {
+ template <typename NodeT> DynTypedNodeList getParents(const NodeT &Node) {
return getParents(ast_type_traits::DynTypedNode::create(Node));
}
- ArrayRef<ast_type_traits::DynTypedNode>
- getParents(const ast_type_traits::DynTypedNode &Node);
+ DynTypedNodeList getParents(const ast_type_traits::DynTypedNode &Node);
const clang::PrintingPolicy &getPrintingPolicy() const {
return PrintingPolicy;
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