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