//
// 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/Linker.h"
-#include "llvm/ADT/StringMap.h"
-#include "llvm/ADT/SmallPtrSet.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;
LTOCodeGenerator();
~LTOCodeGenerator();
+ // Merge given module, return true on success.
bool addModule(struct LTOModule*, std::string &errMsg);
- bool setDebugInfo(lto_debug_model, std::string &errMsg);
- bool setCodePICModel(lto_codegen_model, std::string &errMsg);
- void setCpu(const char *cpu);
- void addMustPreserveSymbol(const char *sym);
+
+ 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);
- void setCodeGenDebugOptions(const char *opts);
+
+ // 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);
- bool determineTarget(std::string &errMsg);
+
typedef llvm::StringMap<uint8_t> StringSet;
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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