llvm-project/llvm/lib/ExecutionEngine/JITLink/BasicGOTAndStubsBuilder.h

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2.7 KiB
C++

//===--- 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"
namespace llvm {
namespace jitlink {
template <typename BuilderImpl> class BasicGOTAndStubsBuilder {
public:
BasicGOTAndStubsBuilder(AtomGraph &G) : G(G) {}
void run() {
// We're going to be adding new atoms, but we don't want to iterate over
// the newly added ones, so just copy the existing atoms out.
std::vector<DefinedAtom *> DAs(G.defined_atoms().begin(),
G.defined_atoms().end());
for (auto *DA : DAs)
for (auto &E : DA->edges())
if (impl().isGOTEdge(E))
impl().fixGOTEdge(E, getGOTEntryAtom(E.getTarget()));
else if (impl().isExternalBranchEdge(E))
impl().fixExternalBranchEdge(E, getStubAtom(E.getTarget()));
}
protected:
Atom &getGOTEntryAtom(Atom &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);
GOTEntryI =
GOTEntries.insert(std::make_pair(Target.getName(), &GOTEntry)).first;
}
assert(GOTEntryI != GOTEntries.end() && "Could not get GOT entry atom");
return *GOTEntryI->second;
}
Atom &getStubAtom(Atom &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 &StubAtom = impl().createStub(Target);
StubI = Stubs.insert(std::make_pair(Target.getName(), &StubAtom)).first;
}
assert(StubI != Stubs.end() && "Count not get stub atom");
return *StubI->second;
}
AtomGraph &G;
private:
BuilderImpl &impl() { return static_cast<BuilderImpl &>(*this); }
DenseMap<StringRef, DefinedAtom *> GOTEntries;
DenseMap<StringRef, DefinedAtom *> Stubs;
};
} // end namespace jitlink
} // end namespace llvm
#endif // LLVM_LIB_EXECUTIONENGINE_JITLINK_BASICGOTANDSTUBSBUILDER_H