Add missing check to SETCC optimization.

[oota-llvm.git] / tools / lto / LTOCodeGenerator.h

diff --git a/tools/lto/LTOCodeGenerator.h b/tools/lto/LTOCodeGenerator.h
index 601dbfa0449a17ba60500906c8fb1c0f1c2b489b..02633629f9858577b24a12b7ea404b131d471435 100644 (file)
--- a/tools/lto/LTOCodeGenerator.h
+++ b/tools/lto/LTOCodeGenerator.h
@@ -9,6 +9,27 @@
 //
 // 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
@@ -19,6 +40,7 @@
 #include "llvm/ADT/StringMap.h"
 #include "llvm/Linker.h"
 #include <string>
+#include <vector>
 
 namespace llvm {
   class LLVMContext;
@@ -39,44 +61,70 @@ struct LTOCodeGenerator {
   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* mCpu) { _mCpu = mCpu; }
+  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; }
 
-  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);
 
 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);
+                        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*        _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;
+  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