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//===- FunctionImportUtils.h - Importing support utilities -----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the FunctionImportGlobalProcessing class which is used
// to perform the necessary global value handling for function importing.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_UTILS_FUNCTIONIMPORTUTILS_H
#define LLVM_TRANSFORMS_UTILS_FUNCTIONIMPORTUTILS_H
#include "llvm/ADT/SetVector.h"
#include "llvm/IR/ModuleSummaryIndex.h"
namespace llvm {
class Module;
/// Class to handle necessary GlobalValue changes required by ThinLTO
/// function importing, including linkage changes and any necessary renaming.
class FunctionImportGlobalProcessing {
/// The Module which we are exporting or importing functions from.
Module &M;
/// Module summary index passed in for function importing/exporting handling.
const ModuleSummaryIndex &ImportIndex;
/// Globals to import from this module, all other functions will be
/// imported as declarations instead of definitions.
DenseSet<const GlobalValue *> *GlobalsToImport;
/// Set to true if the given ModuleSummaryIndex contains any functions
/// from this source module, in which case we must conservatively assume
/// that any of its functions may be imported into another module
/// as part of a different backend compilation process.
bool HasExportedFunctions = false;
/// Check if we should promote the given local value to global scope.
bool doPromoteLocalToGlobal(const GlobalValue *SGV);
/// Helper methods to check if we are importing from or potentially
/// exporting from the current source module.
bool isPerformingImport() const { return GlobalsToImport != nullptr; }
bool isModuleExporting() const { return HasExportedFunctions; }
/// If we are importing from the source module, checks if we should
/// import SGV as a definition, otherwise import as a declaration.
bool doImportAsDefinition(const GlobalValue *SGV);
/// Get the name for SGV that should be used in the linked destination
/// module. Specifically, this handles the case where we need to rename
/// a local that is being promoted to global scope.
std::string getName(const GlobalValue *SGV);
/// Process globals so that they can be used in ThinLTO. This includes
/// promoting local variables so that they can be reference externally by
/// thin lto imported globals and converting strong external globals to
/// available_externally.
void processGlobalsForThinLTO();
void processGlobalForThinLTO(GlobalValue &GV);
/// Get the new linkage for SGV that should be used in the linked destination
/// module. Specifically, for ThinLTO importing or exporting it may need
/// to be adjusted.
GlobalValue::LinkageTypes getLinkage(const GlobalValue *SGV);
public:
FunctionImportGlobalProcessing(
Module &M, const ModuleSummaryIndex &Index,
DenseSet<const GlobalValue *> *GlobalsToImport = nullptr)
: M(M), ImportIndex(Index), GlobalsToImport(GlobalsToImport) {
// If we have a ModuleSummaryIndex but no function to import,
// then this is the primary module being compiled in a ThinLTO
// backend compilation, and we need to see if it has functions that
// may be exported to another backend compilation.
if (!GlobalsToImport)
HasExportedFunctions = ImportIndex.hasExportedFunctions(M);
}
bool run();
static bool
doImportAsDefinition(const GlobalValue *SGV,
DenseSet<const GlobalValue *> *GlobalsToImport);
};
/// Perform in-place global value handling on the given Module for
/// exported local functions renamed and promoted for ThinLTO.
bool renameModuleForThinLTO(
Module &M, const ModuleSummaryIndex &Index,
DenseSet<const GlobalValue *> *GlobalsToImport = nullptr);
} // End llvm namespace
#endif
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