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//===-LTOCodeGenerator.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 the LTOCodeGenerator class.
//
// LTO compilation consists of three phases: Pre-IPO, IPO and Post-IPO.
//
// The Pre-IPO phase compiles source code into bitcode file. The resulting
// bitcode files, along with object files and libraries, will be fed to the
// linker to through the IPO and Post-IPO phases. By using obj-file extension,
// the resulting bitcode file disguises itself as an object file, and therefore
// obviates the need of writing a special set of the make-rules only for LTO
// compilation.
//
// The IPO phase perform inter-procedural analyses and optimizations, and
// the Post-IPO consists two sub-phases: intra-procedural scalar optimizations
// (SOPT), and intra-procedural target-dependent code generator (CG).
//
// As of this writing, we don't separate IPO and the Post-IPO SOPT. They
// are intermingled together, and are driven by a single pass manager (see
// PassManagerBuilder::populateLTOPassManager()).
//
// The "LTOCodeGenerator" is the driver for the IPO and Post-IPO stages.
// The "CodeGenerator" here is bit confusing. Don't confuse the "CodeGenerator"
// with the machine specific code generator.
//
//===----------------------------------------------------------------------===//
#ifndef LTO_CODE_GENERATOR_H
#define LTO_CODE_GENERATOR_H
#include "llvm-c/lto.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Linker.h"
#include <string>
#include <vector>
#include "LTOPartition.h"
namespace llvm {
class LLVMContext;
class GlobalValue;
class Mangler;
class MemoryBuffer;
class TargetMachine;
class raw_ostream;
}
//===----------------------------------------------------------------------===//
/// LTOCodeGenerator - C++ class which implements the opaque lto_code_gen_t
/// type.
///
struct LTOCodeGenerator {
static const char *getVersionString();
LTOCodeGenerator();
~LTOCodeGenerator();
// Merge given module, return true on success.
bool addModule(struct LTOModule*, std::string &errMsg);
void setDebugInfo(lto_debug_model);
void setCodePICModel(lto_codegen_model);
void setCpu(const char* mCpu) { _mCpu = mCpu; }
void addMustPreserveSymbol(const char* sym) {
_mustPreserveSymbols[sym] = 1;
}
// To pass options to the driver and optimization passes. These options are
// not necessarily for debugging purpose (The function name is misleading).
// This function should be called before LTOCodeGenerator::compilexxx(),
// and LTOCodeGenerator::writeMergedModules().
//
void setCodeGenDebugOptions(const char *opts);
// Write the merged module to the file specified by the given path.
// Return true on success.
bool writeMergedModules(const char *path, std::string &errMsg);
// Compile the merged module into a *single* object file; the path to object
// file is returned to the caller via argument "name". Return true on
// success.
//
// NOTE that it is up to the linker to remove the intermediate object file.
// Do not try to remove the object file in LTOCodeGenerator's destructor
// as we don't who (LTOCodeGenerator or the obj file) will last longer.
//
bool compile_to_file(const char **name, std::string &errMsg);
// As with compile_to_file(), this function compiles the merged module into
// single object file. Instead of returning the object-file-path to the caller
// (linker), it brings the object to a buffer, and return the buffer to the
// caller. This function should delete intermediate object file once its content
// is brought to memory. Return NULL is the compilation was not successful.
//
const void *compile(size_t *length, std::string &errMsg);
// Return the paths of the intermediate files that linker needs to delete
// before it exits. The paths are delimited by a single '\0', and the last
// path is ended by double '\0's. The file could be a directory. In that
// case, the entire directory should be erased recusively. This function
// must be called after the compilexxx() is successfuly called, because
// only after that moment, compiler is aware which files need to be removed.
// If calling compilexxx() is not successful, it is up to compiler to clean
// up all the intermediate files generated during the compilation process.
//
const char *getFilesNeedToRemove();
private:
void initializeLTOPasses();
bool determineTarget(std::string &errMsg);
void parseOptions();
bool prepareBeforeCompile(std::string &ErrMsg);
void performIPO(bool PerformPartition, std::string &ErrMsg);
bool performPostIPO(std::string &ErrMsg, bool MergeObjs = false,
const char **MergObjPath = 0);
bool generateObjectFile(llvm::raw_ostream &out, std::string &errMsg);
void applyScopeRestrictions();
void applyRestriction(llvm::GlobalValue &GV,
std::vector<const char*> &mustPreserveList,
llvm::SmallPtrSet<llvm::GlobalValue*, 8> &asmUsed,
llvm::Mangler &mangler);
typedef llvm::StringMap<uint8_t> StringSet;
llvm::LLVMContext& _context;
llvm::Linker _linker;
llvm::TargetMachine* _target;
bool _emitDwarfDebugInfo;
bool _scopeRestrictionsDone;
lto_codegen_model _codeModel;
StringSet _mustPreserveSymbols;
StringSet _asmUndefinedRefs;
llvm::MemoryBuffer* _nativeObjectFile;
std::vector<char*> _codegenOptions;
std::string _mCpu;
std::string _nativeObjectPath;
// To manage the partitions. If partition is not enabled, the whole merged
// module is considered as a single degenerated partition, and the "manager"
// is still active.
lto::IPOPartMgr PartitionMgr;
// To manage the intermediate files during the compilations.
lto::IPOFileMgr FileMgr;
// Sometimes we need to return a vector of strings in a "C" way (to work with
// the C-APIs). We encode such C-thinking string vector by concatenating all
// strings tegother with a single '\0' as the delimitor, the last string ended
// by double '\0's.
SmallVector<char, 4> ConcatStrings;
// Make sure command line is parsed only once. It would otherwise complain
// and quite prematurely.
bool OptionsParsed;
};
#endif // LTO_CODE_GENERATOR_H
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