108 lines
3.5 KiB
C
108 lines
3.5 KiB
C
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//===--- BasicGOTAndStubsBuilder.h - Generic GOT/Stub creation --*- 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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// A base for simple GOT and stub creation.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_EXECUTIONENGINE_JITLINK_BASICGOTANDSTUBSBUILDER_H
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#define LLVM_LIB_EXECUTIONENGINE_JITLINK_BASICGOTANDSTUBSBUILDER_H
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#include "llvm/ExecutionEngine/JITLink/JITLink.h"
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#define DEBUG_TYPE "jitlink"
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namespace llvm {
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namespace jitlink {
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template <typename BuilderImpl> class BasicGOTAndStubsBuilder {
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public:
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BasicGOTAndStubsBuilder(LinkGraph &G) : G(G) {}
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void run() {
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// We're going to be adding new blocks, but we don't want to iterate over
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// the newly added ones, so just copy the existing blocks out.
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std::vector<Block *> Blocks(G.blocks().begin(), G.blocks().end());
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LLVM_DEBUG(dbgs() << "Creating GOT entries and stubs:\n");
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for (auto *B : Blocks)
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for (auto &E : B->edges())
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if (impl().isGOTEdge(E)) {
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LLVM_DEBUG({
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dbgs() << " Updating GOT edge ";
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printEdge(dbgs(), *B, E, "<target GOT>");
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dbgs() << "\n";
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});
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impl().fixGOTEdge(E, getGOTEntrySymbol(E.getTarget()));
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} else if (impl().isExternalBranchEdge(E)) {
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LLVM_DEBUG({
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dbgs() << " Updating external branch edge ";
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printEdge(dbgs(), *B, E, "<target PC-rel>");
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dbgs() << "\n";
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});
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impl().fixExternalBranchEdge(E, getStubSymbol(E.getTarget()));
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}
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}
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protected:
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Symbol &getGOTEntrySymbol(Symbol &Target) {
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assert(Target.hasName() && "GOT edge cannot point to anonymous target");
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auto GOTEntryI = GOTEntries.find(Target.getName());
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// Build the entry if it doesn't exist.
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if (GOTEntryI == GOTEntries.end()) {
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auto &GOTEntry = impl().createGOTEntry(Target);
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LLVM_DEBUG({
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dbgs() << " Created GOT entry for " << Target.getName() << ": "
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<< GOTEntry << "\n";
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});
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GOTEntryI =
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GOTEntries.insert(std::make_pair(Target.getName(), &GOTEntry)).first;
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}
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assert(GOTEntryI != GOTEntries.end() && "Could not get GOT entry symbol");
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LLVM_DEBUG(
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{ dbgs() << " Using GOT entry " << *GOTEntryI->second << "\n"; });
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return *GOTEntryI->second;
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}
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Symbol &getStubSymbol(Symbol &Target) {
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assert(Target.hasName() &&
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"External branch edge can not point to an anonymous target");
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auto StubI = Stubs.find(Target.getName());
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if (StubI == Stubs.end()) {
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auto &StubSymbol = impl().createStub(Target);
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LLVM_DEBUG({
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dbgs() << " Created stub for " << Target.getName() << ": "
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<< StubSymbol << "\n";
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});
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StubI = Stubs.insert(std::make_pair(Target.getName(), &StubSymbol)).first;
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}
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assert(StubI != Stubs.end() && "Count not get stub symbol");
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LLVM_DEBUG({ dbgs() << " Using stub " << *StubI->second << "\n"; });
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return *StubI->second;
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}
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LinkGraph &G;
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private:
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BuilderImpl &impl() { return static_cast<BuilderImpl &>(*this); }
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DenseMap<StringRef, Symbol *> GOTEntries;
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DenseMap<StringRef, Symbol *> Stubs;
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};
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} // end namespace jitlink
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} // end namespace llvm
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#endif // LLVM_LIB_EXECUTIONENGINE_JITLINK_BASICGOTANDSTUBSBUILDER_H
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