Sink undesirable LTO functions into the old C API

We want to encourage users of the C++ LTO API to reuse memory buffers instead
of repeatedly opening and reading the same file contents.

This reverts commit r212305 and implements a tidier scheme.

llvm-svn: 212308

include/llvm/LTO/LTOModule.h

@@ -70,13 +70,14 @@ public:
   static bool isBitcodeFile(const void *mem, size_t length);
   static bool isBitcodeFile(const char *path);
 
-  /// 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);
+  /// Returns 'true' if the memory buffer is LLVM bitcode for the specified
+  /// triple.
+  static bool isBitcodeForTarget(MemoryBuffer *memBuffer,
+                                 StringRef triplePrefix);
+
+  /// Create a MemoryBuffer from a memory range with an optional name.
+  static MemoryBuffer *makeBuffer(const void *mem, size_t length,
+                                  StringRef name = "");
 
   /// Create an LTOModule. N.B. These methods take ownership of the buffer. The
   /// caller must have initialized the Targets, the TargetMCs, the AsmPrinters,
@@ -202,17 +203,10 @@ private:
   /// Get string that the data pointer points to.
   bool objcClassNameFromExpression(const Constant *c, std::string &name);
 
-  /// Returns 'true' if the bitcode BC is for the specified target triple.
-  static bool isTargetMatch(StringRef BC, const char *TriplePrefix);
-
   /// Create an LTOModule (private version). N.B. This method takes ownership of
   /// the buffer.
   static LTOModule *makeLTOModule(std::unique_ptr<MemoryBuffer> Buffer,
                                   TargetOptions options, std::string &errMsg);
-
-  /// Create a MemoryBuffer from a memory range with an optional name.
-  static MemoryBuffer *makeBuffer(const void *mem, size_t length,
-                                  StringRef name = "");
 };
 }
 #endif // LTO_MODULE_H

lib/LTO/LTOModule.cpp

@@ -68,30 +68,9 @@ bool LTOModule::isBitcodeFile(const char *path) {
   return type == sys::fs::file_magic::bitcode;
 }
 
-/// isBitcodeFileForTarget - Returns 'true' if the file (or memory contents) is
-/// LLVM bitcode for the specified triple.
-bool LTOModule::isBitcodeFileForTarget(const void *mem, size_t length,
-                                       const char *triplePrefix) {
-  MemoryBuffer *buffer = makeBuffer(mem, length);
-  if (!buffer)
-    return false;
-  return isTargetMatch(StringRef((const char *)mem, length), triplePrefix);
-}
-
-bool LTOModule::isBitcodeFileForTarget(const char *path,
-                                       const char *triplePrefix) {
-  std::unique_ptr<MemoryBuffer> buffer;
-  if (MemoryBuffer::getFile(path, buffer))
-    return false;
-  return isTargetMatch(buffer->getBuffer(), triplePrefix);
-}
-
-/// Returns 'true' if the bitcode BC is for the specified target triple.
-bool LTOModule::isTargetMatch(StringRef BC, const char *TriplePrefix) {
-  std::unique_ptr<MemoryBuffer> Buffer(
-      MemoryBuffer::getMemBuffer(BC, "", false));
-  std::string Triple = getBitcodeTargetTriple(Buffer.get(), getGlobalContext());
-  return strncmp(Triple.c_str(), TriplePrefix, strlen(TriplePrefix)) == 0;
+bool LTOModule::isBitcodeForTarget(MemoryBuffer *buffer,
+                                   StringRef triplePrefix) {
+  return getBitcodeTargetTriple(buffer, getGlobalContext()) == triplePrefix;
 }
 
 LTOModule *LTOModule::createFromFile(const char *path, TargetOptions options,

tools/lto/lto.cpp

@@ -16,6 +16,7 @@
 #include "llvm/CodeGen/CommandFlags.h"
 #include "llvm/LTO/LTOCodeGenerator.h"
 #include "llvm/LTO/LTOModule.h"
+#include "llvm/Support/MemoryBuffer.h"
 #include "llvm/Support/TargetSelect.h"
 
 // extra command-line flags needed for LTOCodeGenerator
@@ -87,7 +88,10 @@ bool lto_module_is_object_file(const char* path) {
 
 bool lto_module_is_object_file_for_target(const char* path,
                                           const char* target_triplet_prefix) {
-  return LTOModule::isBitcodeFileForTarget(path, target_triplet_prefix);
+  std::unique_ptr<MemoryBuffer> buffer;
+  if (MemoryBuffer::getFile(path, buffer))
+    return false;
+  return LTOModule::isBitcodeForTarget(buffer.get(), target_triplet_prefix);
 }
 
 bool lto_module_is_object_file_in_memory(const void* mem, size_t length) {
@@ -98,7 +102,10 @@ bool
 lto_module_is_object_file_in_memory_for_target(const void* mem,
                                             size_t length,
                                             const char* target_triplet_prefix) {
-  return LTOModule::isBitcodeFileForTarget(mem, length, target_triplet_prefix);
+  std::unique_ptr<MemoryBuffer> buffer(LTOModule::makeBuffer(mem, length));
+  if (!buffer)
+    return false;
+  return LTOModule::isBitcodeForTarget(buffer.get(), target_triplet_prefix);
 }
 
 lto_module_t lto_module_create(const char* path) {