llvm-project/clang-tools-extra/clangd/support/MemoryTree.h

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//===--- MemoryTree.h - A special tree for components and sizes -*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANGD_SUPPORT_MEMORYTREE_H_
#define LLVM_CLANG_TOOLS_EXTRA_CLANGD_SUPPORT_MEMORYTREE_H_
#include "Trace.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Allocator.h"
#include <cstddef>
#include <string>
#include <vector>
namespace clang {
namespace clangd {
/// A tree that can be used to represent memory usage of nested components while
/// preserving the hierarchy.
/// Edges have associated names. An edge that might not be interesting to all
/// traversers or costly to copy (e.g. file names) can be marked as "detail".
/// Tree construction allows chosing between a detailed and brief mode, in brief
/// mode all "detail" edges are ignored and tree is constructed without any
/// string copies.
struct MemoryTree {
public:
/// If Alloc is nullptr, tree is in brief mode and will ignore detail edges.
MemoryTree(llvm::BumpPtrAllocator *DetailAlloc = nullptr)
: DetailAlloc(DetailAlloc) {}
/// No copy of the \p Name.
/// Note that returned pointers are invalidated with subsequent calls to
/// child/detail.
MemoryTree &child(llvm::StringLiteral Name) { return createChild(Name); }
MemoryTree(const MemoryTree &) = delete;
MemoryTree &operator=(const MemoryTree &) = delete;
MemoryTree(MemoryTree &&) = default;
MemoryTree &operator=(MemoryTree &&) = default;
/// Makes a copy of the \p Name in detailed mode, returns current node
/// otherwise.
/// Note that returned pointers are invalidated with subsequent calls to
/// child/detail.
MemoryTree &detail(llvm::StringRef Name) {
return DetailAlloc ? createChild(Name.copy(*DetailAlloc)) : *this;
}
/// Increases size of current node by \p Increment.
void addUsage(size_t Increment) { Size += Increment; }
/// Returns edges to direct children of this node.
const llvm::DenseMap<llvm::StringRef, MemoryTree> &children() const;
/// Returns total number of bytes used by this sub-tree. Performs a traversal.
size_t total() const;
/// Returns total number of bytes used by this node only.
size_t self() const { return Size; }
private:
/// Adds a child with an edge labeled as \p Name. Multiple calls to this
/// function returns the same node.
MemoryTree &createChild(llvm::StringRef Name);
/// Allocator to use for detailed edge names.
llvm::BumpPtrAllocator *DetailAlloc = nullptr;
/// Bytes owned by this component specifically.
size_t Size = 0;
/// Edges from current node to its children. Keys are the labels for edges.
llvm::DenseMap<llvm::StringRef, MemoryTree> Children;
};
/// Records total memory usage of each node under \p Out. Labels are edges on
/// the path joined with ".", starting with \p RootName.
void record(const MemoryTree &MT, std::string RootName,
const trace::Metric &Out);
} // namespace clangd
} // namespace clang
#endif