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//===-- llvm/LinkTimeOptimizer.h - Public Interface ------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Devang Patel and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This header provides public interface to use LLVM link time optimization
// library. This is intended to be used by linker to do link time optimization.
//
//===----------------------------------------------------------------------===//
#ifndef __LTO_H__
#define __LTO_H__
#include <string>
#include <vector>
#include <set>
#include <llvm/ADT/hash_map>
namespace llvm {
class Module;
class GlobalValue;
enum LTOStatus {
LTO_UNKNOWN,
LTO_OPT_SUCCESS,
LTO_READ_SUCCESS,
LTO_READ_FAILURE,
LTO_WRITE_FAILURE,
LTO_NO_TARGET,
LTO_NO_WORK,
LTO_MODULE_MERGE_FAILURE,
LTO_ASM_FAILURE
};
enum LTOLinkageTypes {
LTOExternalLinkage, // Externally visible function
LTOLinkOnceLinkage, // Keep one copy of named function when linking (inline)
LTOWeakLinkage, // Keep one copy of named function when linking (weak)
LTOInternalLinkage // Rename collisions when linking (static functions)
};
/// This class represents LLVM symbol information without exposing details
/// of LLVM global values. It encapsulates symbol linkage information. This
/// is typically used in hash_map where associated name identifies the
/// the symbol name.
class LLVMSymbol {
public:
LTOLinkageTypes getLinkage() const { return linkage; }
void mayBeNotUsed();
LLVMSymbol (enum LTOLinkageTypes lt, GlobalValue *g) : linkage(lt), gv(g) {}
private:
enum LTOLinkageTypes linkage;
GlobalValue *gv;
};
class string_compare {
public:
bool operator()(const char* left, const char* right) const {
return (strcmp(left, right) == 0);
}
};
/// This is the main link time optimization class. It exposes simple API
/// to perform link time optimization using LLVM intermodular optimizer.
class LinkTimeOptimizer {
public:
typedef hash_map<const char*, LLVMSymbol*, hash<const char*>,
string_compare> NameToSymbolMap;
enum LTOStatus readLLVMObjectFile(const std::string &InputFilename,
NameToSymbolMap &symbols,
std::set<const char*> &references);
enum LTOStatus optimizeModules(const std::string &OutputFilename,
std::vector<const char*> &exportList);
private:
std::vector<Module *> modules;
NameToSymbolMap allSymbols;
};
} // End llvm namespace
/// This provides C interface to initialize link time optimizer. This allows
/// linker to use dlopen() interface to dynamically load LinkTimeOptimizer.
/// extern "C" helps, because dlopen() interface uses name to find the symbol.
extern "C"
llvm::LinkTimeOptimizer *createLLVMOptimizer();
#endif
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