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Teresa Johnson 655b4d9f20 [ThinLTO] Refactor ODR resolution and internalization (NFC)
Move the now index-based ODR resolution and internalization routines out
of ThinLTOCodeGenerator.cpp and into either LTO.cpp (index-based
analysis) or FunctionImport.cpp (index-driven optimizations).
This is to enable usage by other linkers.

llvm-svn: 270698
2016-05-25 14:03:11 +00:00

77 lines
2.7 KiB
C++

//===-LTO.h - LLVM Link Time Optimizer ------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares functions and classes used to support LTO. It is intended
// to be used both by LTO classes as well as by clients (gold-plugin) that
// don't utilize the LTO code generator interfaces.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LTO_LTO_H
#define LLVM_LTO_LTO_H
#include "llvm/ADT/StringMap.h"
#include "llvm/IR/ModuleSummaryIndex.h"
namespace llvm {
class LLVMContext;
class MemoryBufferRef;
class Module;
/// Helper to load a module from bitcode.
std::unique_ptr<Module> loadModuleFromBuffer(const MemoryBufferRef &Buffer,
LLVMContext &Context, bool Lazy);
/// Provide a "loader" for the FunctionImporter to access function from other
/// modules.
class ModuleLoader {
/// The context that will be used for importing.
LLVMContext &Context;
/// Map from Module identifier to MemoryBuffer. Used by clients like the
/// FunctionImported to request loading a Module.
StringMap<MemoryBufferRef> &ModuleMap;
public:
ModuleLoader(LLVMContext &Context, StringMap<MemoryBufferRef> &ModuleMap)
: Context(Context), ModuleMap(ModuleMap) {}
/// Load a module on demand.
std::unique_ptr<Module> operator()(StringRef Identifier) {
return loadModuleFromBuffer(ModuleMap[Identifier], Context, /*Lazy*/ true);
}
};
/// Resolve Weak and LinkOnce values in the \p Index. Linkage changes recorded
/// in the index and the ThinLTO backends must apply the changes to the Module
/// via thinLTOResolveWeakForLinkerModule.
///
/// This is done for correctness (if value exported, ensure we always
/// emit a copy), and compile-time optimization (allow drop of duplicates).
void thinLTOResolveWeakForLinkerInIndex(
ModuleSummaryIndex &Index,
std::function<bool(GlobalValue::GUID, const GlobalValueSummary *)>
isPrevailing,
std::function<bool(StringRef, GlobalValue::GUID)> isExported,
std::function<void(StringRef, GlobalValue::GUID, GlobalValue::LinkageTypes)>
recordNewLinkage);
/// Update the linkages in the given \p Index to mark exported values
/// as external and non-exported values as internal. The ThinLTO backends
/// must apply the changes to the Module via thinLTOInternalizeModule.
void thinLTOInternalizeAndPromoteInIndex(
ModuleSummaryIndex &Index,
std::function<bool(StringRef, GlobalValue::GUID)> isExported);
}
#endif