llvm/llvm/lib/ExecutionEngine/JITLink/DefineExternalSectionStartAndEndSymbols.h

//===--------- DefineExternalSectionStartAndEndSymbols.h --------*- 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
//
//===----------------------------------------------------------------------===//
//
// Utility class for recognizing external section start and end symbols and
// transforming them into defined symbols for the start and end blocks of the
// associated Section.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_EXECUTIONENGINE_JITLINK_DEFINEEXTERNALSECTIONSTARTANDENDSYMBOLS_H
#define LLVM_EXECUTIONENGINE_JITLINK_DEFINEEXTERNALSECTIONSTARTANDENDSYMBOLS_H

#include "llvm/ExecutionEngine/JITLink/JITLink.h"
#include "llvm/Support/Debug.h"

#define DEBUG_TYPE …

namespace llvm {
namespace jitlink {

struct SectionRangeSymbolDesc { … };

/// Pass implementation for the createDefineExternalSectionStartAndEndSymbols
/// function.
template <typename SymbolIdentifierFunction>
class DefineExternalSectionStartAndEndSymbols { … };

/// Returns a JITLink pass (as a function class) that uses the given symbol
/// identification function to identify external section start and end symbols
/// (and their associated Section*s) and transform the identified externals
/// into defined symbols pointing to the start of the first block in the
/// section and the end of the last (start and end symbols for empty sections
/// will be transformed into absolute symbols at address 0).
///
/// The identification function should be callable as
///
///   SectionRangeSymbolDesc (LinkGraph &G, Symbol &Sym)
///
/// If Sym is not a section range start or end symbol then a default
/// constructed SectionRangeSymbolDesc should be returned. If Sym is a start
/// symbol then SectionRangeSymbolDesc(Sec, true), where Sec is a reference to
/// the target Section. If Sym is an end symbol then
/// SectionRangeSymbolDesc(Sec, false) should be returned.
///
/// This pass should be run in the PostAllocationPass pipeline, at which point
/// all blocks should have been assigned their final addresses.
template <typename SymbolIdentifierFunction>
DefineExternalSectionStartAndEndSymbols<SymbolIdentifierFunction>
createDefineExternalSectionStartAndEndSymbolsPass(
    SymbolIdentifierFunction &&F) { … }

/// ELF section start/end symbol detection.
inline SectionRangeSymbolDesc
identifyELFSectionStartAndEndSymbols(LinkGraph &G, Symbol &Sym) { … }

/// MachO section start/end symbol detection.
inline SectionRangeSymbolDesc
identifyMachOSectionStartAndEndSymbols(LinkGraph &G, Symbol &Sym) { … }

} // end namespace jitlink
} // end namespace llvm

#undef DEBUG_TYPE

#endif // LLVM_EXECUTIONENGINE_JITLINK_DEFINEEXTERNALSECTIONSTARTANDENDSYMBOLS_H