llvm-6502/include/llvm/LTO/LTOCodeGenerator.h
Peter Collingbourne 416d8ecf80 libLTO, llvm-lto, gold: Introduce flag for controlling optimization level.
This change also introduces a link-time optimization level of 1. This
optimization level runs only the globaldce pass as well as cleanup passes for
passes that run at -O0, specifically simplifycfg which cleans up lowerbitsets.

http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20150316/266951.html

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@232769 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-19 22:01:00 +00:00

179 lines
6.7 KiB
C++

//===-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 LLVM_LTO_LTOCODEGENERATOR_H
#define LLVM_LTO_LTOCODEGENERATOR_H
#include "llvm-c/lto.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Linker/Linker.h"
#include "llvm/Target/TargetOptions.h"
#include <string>
#include <vector>
namespace llvm {
class LLVMContext;
class DiagnosticInfo;
class GlobalValue;
class Mangler;
class MemoryBuffer;
class TargetLibraryInfo;
class TargetMachine;
class raw_ostream;
//===----------------------------------------------------------------------===//
/// C++ class which implements the opaque lto_code_gen_t type.
///
struct LTOCodeGenerator {
static const char *getVersionString();
LTOCodeGenerator();
LTOCodeGenerator(std::unique_ptr<LLVMContext> Context);
~LTOCodeGenerator();
// Merge given module, return true on success.
bool addModule(struct LTOModule *);
// Set the destination module.
void setModule(struct LTOModule *);
void setTargetOptions(TargetOptions options);
void setDebugInfo(lto_debug_model);
void setCodePICModel(lto_codegen_model);
void setCpu(const char *mCpu) { MCpu = mCpu; }
void setAttr(const char *mAttr) { MAttr = mAttr; }
void setOptLevel(unsigned optLevel) { OptLevel = optLevel; }
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);
// Parse the options set in setCodeGenDebugOptions. Like
// setCodeGenDebugOptions, this must be called before
// LTOCodeGenerator::compilexxx() and LTOCodeGenerator::writeMergedModules()
void parseCodeGenDebugOptions();
// 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,
bool disableInline,
bool disableGVNLoadPRE,
bool disableVectorization,
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 if the compilation was not successful.
const void *compile(size_t *length,
bool disableInline,
bool disableGVNLoadPRE,
bool disableVectorization,
std::string &errMsg);
// Optimizes the merged module. Returns true on success.
bool optimize(bool disableInline,
bool disableGVNLoadPRE,
bool disableVectorization,
std::string &errMsg);
// Compiles the merged optimized module into a single object file. It brings
// the object to a buffer, and returns the buffer to the caller. Return NULL
// if the compilation was not successful.
const void *compileOptimized(size_t *length, std::string &errMsg);
void setDiagnosticHandler(lto_diagnostic_handler_t, void *);
LLVMContext &getContext() { return Context; }
private:
void initializeLTOPasses();
bool compileOptimized(raw_ostream &out, std::string &errMsg);
bool compileOptimizedToFile(const char **name, std::string &errMsg);
void applyScopeRestrictions();
void applyRestriction(GlobalValue &GV, ArrayRef<StringRef> Libcalls,
std::vector<const char *> &MustPreserveList,
SmallPtrSetImpl<GlobalValue *> &AsmUsed,
Mangler &Mangler);
bool determineTarget(std::string &errMsg);
static void DiagnosticHandler(const DiagnosticInfo &DI, void *Context);
void DiagnosticHandler2(const DiagnosticInfo &DI);
typedef StringMap<uint8_t> StringSet;
void initialize();
void destroyMergedModule();
std::unique_ptr<LLVMContext> OwnedContext;
LLVMContext &Context;
Linker IRLinker;
TargetMachine *TargetMach;
bool EmitDwarfDebugInfo;
bool ScopeRestrictionsDone;
lto_codegen_model CodeModel;
StringSet MustPreserveSymbols;
StringSet AsmUndefinedRefs;
std::unique_ptr<MemoryBuffer> NativeObjectFile;
std::vector<char *> CodegenOptions;
std::string MCpu;
std::string MAttr;
std::string NativeObjectPath;
TargetOptions Options;
unsigned OptLevel;
lto_diagnostic_handler_t DiagHandler;
void *DiagContext;
LTOModule *OwnedModule;
};
}
#endif