Add C wrappers for the LTO library (PR1081). Patch by Chandler Carruth!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32966 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm-c/LinkTimeOptimizer.h

@@ -0,0 +1,58 @@
+//===-- llvm/LinkTimeOptimizer.h - LTO Public C Interface -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chandler Carruth and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This header provides a C API to use the LLVM link time optimization
+// library. This is inteded to be used by linkers which are C-only in
+// their implementation for performing LTO.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef __LTO_CAPI_H__
+#define __LTO_CAPI_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+  /// This provides a dummy type for pointers to the LTO object.
+  typedef void* llvm_lto_t;
+
+  /// This provides a C-visible enumerator to manage status codes.
+  /// This should map exactly onto the C++ enumerator LTOStatus.
+  typedef enum llvm_lto_status {
+    LLVM_LTO_UNKNOWN,
+    LLVM_LTO_OPT_SUCCESS,
+    LLVM_LTO_READ_SUCCESS,
+    LLVM_LTO_READ_FAILURE,
+    LLVM_LTO_WRITE_FAILURE,
+    LLVM_LTO_NO_TARGET,
+    LLVM_LTO_NO_WORK,
+    LLVM_LTO_MODULE_MERGE_FAILURE,
+    LLVM_LTO_ASM_FAILURE,
+
+    //  Added C-specific error codes
+    LLVM_LTO_NULL_OBJECT
+  } llvm_lto_status_t;
+ 
+  /// This provides C interface to initialize link time optimizer. This allows
+  /// linker to use dlopen() interface to dynamically load LinkTimeOptimizer.
+  /// extern "C" helps, because dlopen() interface uses name to find the symbol.
+  extern llvm_lto_t llvm_create_optimizer(void);
+  extern void llvm_destroy_optimizer(llvm_lto_t lto);
+
+  extern llvm_lto_status_t llvm_read_object_file
+    (llvm_lto_t lto, const char* input_filename);
+  extern llvm_lto_status_t llvm_optimize_modules
+    (llvm_lto_t lto, const char* output_filename);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

tools/lto/lto-c.cpp

@@ -0,0 +1,66 @@
+//===- lto-c.cpp - LLVM Link Time Optimizer C Wrappers --------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Chandler Carruth and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file implements a C wrapper API for the Link Time Optimization
+// library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm-c/LinkTimeOptimizer.h"
+#include "llvm/LinkTimeOptimizer.h"
+using namespace llvm;
+
+
+/// Create an instance of the LLVM LTO object for performing the link
+/// time optimizations.
+extern "C"
+llvm_lto_t llvm_create_optimizer() {
+  return new llvm::LTO();
+}
+
+/// Destroy an instance of the LLVM LTO object
+extern "C"
+void llvm_destroy_optimizer(llvm_lto_t lto) {
+  delete (llvm::LTO*)lto;
+}
+
+/// Read an LLVM bytecode file using LTO::readLLVMObjectFile.
+extern "C"
+llvm_lto_status
+llvm_read_object_file(llvm_lto_t lto, const char *input_filename) {
+  llvm::LTO *l = (llvm::LTO*)lto;
+
+  if (input_filename == NULL)
+    return LLVM_LTO_READ_FAILURE;
+
+  std::string InputFilename(input_filename);
+  llvm::LTO::NameToSymbolMap symbols;
+  std::set<std::string> references;
+  return (llvm_lto_status)((int)(l->readLLVMObjectFile(InputFilename, symbols,
+                                                       references)));
+}
+
+
+/// Optimize and output object code using LTO::optimizeModules.
+extern "C"
+llvm_lto_status
+llvm_optimize_modules(llvm_lto_t lto, const char *output_filename) {
+  llvm::LTO *l = (llvm::LTO*)lto;
+
+  std::string OutputFilename(output_filename);
+  std::vector<const char *> exportList;
+  std::string targetTriple;
+
+  return (llvm_lto_status)((int)(
+    l->optimizeModules(OutputFilename, exportList,
+                       targetTriple, false, "")));
+}
+
+
+