Move LTO support library to a component, allowing it to be tested

more reliably across platforms.  Patch by Tom Roeder!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@191343 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 326 insertions, 0 deletions

diff --git a/include/llvm/LTO/LTOCodeGenerator.h b/include/llvm/LTO/LTOCodeGenerator.h
new file mode 100644
index 0000000000..3d151b93af
--- /dev/null
+++ b/include/llvm/LTO/LTOCodeGenerator.h
@@ -0,0 +1,130 @@
+//===-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>
+
+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 if the compilation was not successful. 
+  //
+  const void *compile(size_t *length, std::string &errMsg);
+
+private:
+  void initializeLTOPasses();
+
+  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;
+
+  llvm::LLVMContext &Context;
+  llvm::Linker Linker;
+  llvm::TargetMachine *TargetMach;
+  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;
+};
+
+#endif // LTO_CODE_GENERATOR_H
diff --git a/include/llvm/LTO/LTOModule.h b/include/llvm/LTO/LTOModule.h
new file mode 100644
index 0000000000..973466cc0e
--- /dev/null
+++ b/include/llvm/LTO/LTOModule.h
@@ -0,0 +1,196 @@
+//===-LTOModule.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 LTOModule class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LTO_MODULE_H
+#define LTO_MODULE_H
+
+#include "llvm-c/lto.h"
+#include "llvm/ADT/OwningPtr.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/IR/Module.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/Target/Mangler.h"
+#include "llvm/Target/TargetMachine.h"
+#include <string>
+#include <vector>
+
+// Forward references to llvm classes.
+namespace llvm {
+  class Function;
+  class GlobalValue;
+  class MemoryBuffer;
+  class TargetOptions;
+  class Value;
+}
+
+//===----------------------------------------------------------------------===//
+/// LTOModule - C++ class which implements the opaque lto_module_t type.
+///
+struct LTOModule {
+private:
+  typedef llvm::StringMap<uint8_t> StringSet;
+
+  struct NameAndAttributes {
+    const char        *name;
+    uint32_t           attributes;
+    bool               isFunction;
+    const llvm::GlobalValue *symbol;
+  };
+
+  llvm::OwningPtr<llvm::Module>           _module;
+  llvm::OwningPtr<llvm::TargetMachine>    _target;
+  std::vector<NameAndAttributes>          _symbols;
+
+  // _defines and _undefines only needed to disambiguate tentative definitions
+  StringSet                               _defines;
+  llvm::StringMap<NameAndAttributes>      _undefines;
+  std::vector<const char*>                _asm_undefines;
+  llvm::MCContext                         _context;
+
+  // Use mangler to add GlobalPrefix to names to match linker names.
+  llvm::Mangler                           _mangler;
+
+  LTOModule(llvm::Module *m, llvm::TargetMachine *t);
+public:
+  /// isBitcodeFile - Returns 'true' if the file or memory contents is LLVM
+  /// bitcode.
+  static bool isBitcodeFile(const void *mem, size_t length);
+  static bool isBitcodeFile(const char *path);
+
+  /// isBitcodeFileForTarget - Returns 'true' if the file or memory contents
+  /// is LLVM bitcode for the specified triple.
+  static bool isBitcodeFileForTarget(const void *mem,
+                                     size_t length,
+                                     const char *triplePrefix);
+  static bool isBitcodeFileForTarget(const char *path,
+                                     const char *triplePrefix);
+
+  /// makeLTOModule - Create an LTOModule. N.B. These methods take ownership
+  /// of the buffer. The caller must have initialized the Targets, the
+  /// TargetMCs, the AsmPrinters, and the AsmParsers by calling:
+  ///
+  /// InitializeAllTargets();
+  /// InitializeAllTargetMCs();
+  /// InitializeAllAsmPrinters();
+  /// InitializeAllAsmParsers();
+  static LTOModule *makeLTOModule(const char* path,
+                                  std::string &errMsg);
+  static LTOModule *makeLTOModule(int fd, const char *path,
+                                  size_t size, std::string &errMsg);
+  static LTOModule *makeLTOModule(int fd, const char *path,
+                                  size_t map_size,
+                                  off_t offset,
+                                  std::string& errMsg);
+  static LTOModule *makeLTOModule(const void *mem, size_t length,
+                                  std::string &errMsg);
+
+  /// getTargetTriple - Return the Module's target triple.
+  const char *getTargetTriple() {
+    return _module->getTargetTriple().c_str();
+  }
+
+  /// setTargetTriple - Set the Module's target triple.
+  void setTargetTriple(const char *triple) {
+    _module->setTargetTriple(triple);
+  }
+
+  /// getSymbolCount - Get the number of symbols
+  uint32_t getSymbolCount() {
+    return _symbols.size();
+  }
+
+  /// getSymbolAttributes - Get the attributes for a symbol at the specified
+  /// index.
+  lto_symbol_attributes getSymbolAttributes(uint32_t index) {
+    if (index < _symbols.size())
+      return lto_symbol_attributes(_symbols[index].attributes);
+    return lto_symbol_attributes(0);
+  }
+
+  /// getSymbolName - Get the name of the symbol at the specified index.
+  const char *getSymbolName(uint32_t index) {
+    if (index < _symbols.size())
+      return _symbols[index].name;
+    return NULL;
+  }
+
+  /// getLLVVMModule - Return the Module.
+  llvm::Module *getLLVVMModule() { return _module.get(); }
+
+  /// getAsmUndefinedRefs -
+  const std::vector<const char*> &getAsmUndefinedRefs() {
+    return _asm_undefines;
+  }
+
+  /// getTargetOptions - Fill the TargetOptions object with the options
+  /// specified on the command line.
+  static void getTargetOptions(llvm::TargetOptions &Options);
+
+private:
+  /// parseSymbols - Parse the symbols from the module and model-level ASM and
+  /// add them to either the defined or undefined lists.
+  bool parseSymbols(std::string &errMsg);
+
+  /// addPotentialUndefinedSymbol - Add a symbol which isn't defined just yet
+  /// to a list to be resolved later.
+  void addPotentialUndefinedSymbol(const llvm::GlobalValue *dcl, bool isFunc);
+
+  /// addDefinedSymbol - Add a defined symbol to the list.
+  void addDefinedSymbol(const llvm::GlobalValue *def, bool isFunction);
+
+  /// addDefinedFunctionSymbol - Add a function symbol as defined to the list.
+  void addDefinedFunctionSymbol(const llvm::Function *f);
+
+  /// addDefinedDataSymbol - Add a data symbol as defined to the list.
+  void addDefinedDataSymbol(const llvm::GlobalValue *v);
+
+  /// addAsmGlobalSymbols - Add global symbols from module-level ASM to the
+  /// defined or undefined lists.
+  bool addAsmGlobalSymbols(std::string &errMsg);
+
+  /// addAsmGlobalSymbol - Add a global symbol from module-level ASM to the
+  /// defined list.
+  void addAsmGlobalSymbol(const char *, lto_symbol_attributes scope);
+
+  /// addAsmGlobalSymbolUndef - Add a global symbol from module-level ASM to
+  /// the undefined list.
+  void addAsmGlobalSymbolUndef(const char *);
+
+  /// addObjCClass - Parse i386/ppc ObjC class data structure.
+  void addObjCClass(const llvm::GlobalVariable *clgv);
+
+  /// addObjCCategory - Parse i386/ppc ObjC category data structure.
+  void addObjCCategory(const llvm::GlobalVariable *clgv);
+
+  /// addObjCClassRef - Parse i386/ppc ObjC class list data structure.
+  void addObjCClassRef(const llvm::GlobalVariable *clgv);
+
+  /// objcClassNameFromExpression - Get string that the data pointer points
+  /// to.
+  bool objcClassNameFromExpression(const llvm::Constant* c, std::string &name);
+
+  /// isTargetMatch - Returns 'true' if the memory buffer is for the specified
+  /// target triple.
+  static bool isTargetMatch(llvm::MemoryBuffer *memBuffer,
+                            const char *triplePrefix);
+
+  /// makeLTOModule - Create an LTOModule (private version). N.B. This
+  /// method takes ownership of the buffer.
+  static LTOModule *makeLTOModule(llvm::MemoryBuffer *buffer,
+                                  std::string &errMsg);
+
+  /// makeBuffer - Create a MemoryBuffer from a memory range.
+  static llvm::MemoryBuffer *makeBuffer(const void *mem, size_t length);
+};
+
+#endif // LTO_MODULE_H