2ccf7ed277
Use SymbolStringPtr for Symbol names in LinkGraph. This reduces string interning on the boundary between JITLink and ORC, and allows pointer comparisons (rather than string comparisons) between Symbol names. This should improve the performance and readability of code that bridges between JITLink and ORC (e.g. ObjectLinkingLayer and ObjectLinkingLayer::Plugins). To enable use of SymbolStringPtr a std::shared_ptr<SymbolStringPool> is added to LinkGraph and threaded through to its construction sites in LLVM and Bolt. All LinkGraphs that are to have symbol names compared by pointer equality must point to the same SymbolStringPool instance, which in ORC sessions should be the pool attached to the ExecutionSession. --------- Co-authored-by: Lang Hames <lhames@gmail.com>
79 lines
2.7 KiB
C++
79 lines
2.7 KiB
C++
//===---------------------- TableManager.h ----------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// Fix edge for edge that needs an entry to reference the target symbol
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_EXECUTIONENGINE_JITLINK_TABLEMANAGER_H
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#define LLVM_EXECUTIONENGINE_JITLINK_TABLEMANAGER_H
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#include "llvm/ExecutionEngine/JITLink/JITLink.h"
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#include "llvm/Support/Debug.h"
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namespace llvm {
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namespace jitlink {
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/// A CRTP base for tables that are built on demand, e.g. Global Offset Tables
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/// and Procedure Linkage Tables.
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/// The getEntyrForTarget function returns the table entry corresponding to the
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/// given target, calling down to the implementation class to build an entry if
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/// one does not already exist.
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template <typename TableManagerImplT> class TableManager {
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public:
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/// Return the constructed entry
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///
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/// Use parameter G to construct the entry for target symbol
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Symbol &getEntryForTarget(LinkGraph &G, Symbol &Target) {
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assert(Target.hasName() && "Edge cannot point to anonymous target");
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auto EntryI = Entries.find(Target.getName());
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// Build the entry if it doesn't exist.
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if (EntryI == Entries.end()) {
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auto &Entry = impl().createEntry(G, Target);
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DEBUG_WITH_TYPE("jitlink", {
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dbgs() << " Created " << impl().getSectionName() << " entry for "
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<< Target.getName() << ": " << Entry << "\n";
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});
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EntryI = Entries.insert(std::make_pair(Target.getName(), &Entry)).first;
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}
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assert(EntryI != Entries.end() && "Could not get entry symbol");
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DEBUG_WITH_TYPE("jitlink", {
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dbgs() << " Using " << impl().getSectionName() << " entry "
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<< *EntryI->second << "\n";
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});
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return *EntryI->second;
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}
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/// Register a pre-existing entry.
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///
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/// Objects may include pre-existing table entries (e.g. for GOTs).
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/// This method can be used to register those entries so that they will not
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/// be duplicated by createEntry the first time that getEntryForTarget is
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/// called.
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bool registerPreExistingEntry(Symbol &Target, Symbol &Entry) {
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assert(Target.hasName() && "Edge cannot point to anonymous target");
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auto Res = Entries.insert({
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Target.getName(),
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&Entry,
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});
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return Res.second;
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}
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private:
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TableManagerImplT &impl() { return static_cast<TableManagerImplT &>(*this); }
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DenseMap<orc::SymbolStringPtr, Symbol *> Entries;
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};
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} // namespace jitlink
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} // namespace llvm
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#endif
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