It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Linker/Linker.cpp b/lib/Linker/Linker.cpp
new file mode 100644
index 0000000..9f9a59d
--- /dev/null
+++ b/lib/Linker/Linker.cpp
@@ -0,0 +1,178 @@
+//===- lib/Linker/Linker.cpp - Basic Linker functionality  ----------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Reid Spencer and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains basic Linker functionality that all usages will need.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Linker.h"
+#include "llvm/Module.h"
+#include "llvm/Bitcode/ReaderWriter.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Streams.h"
+using namespace llvm;
+
+Linker::Linker(const std::string& progname, const std::string& modname, unsigned flags)
+  : Composite(0)
+  , LibPaths()
+  , Flags(flags)
+  , Error()
+  , ProgramName(progname)
+{
+  Composite = new Module(modname);
+}
+
+Linker::Linker(const std::string& progname, Module* aModule, unsigned flags)
+  : Composite(aModule)
+  , LibPaths()
+  , Flags(flags)
+  , Error()
+  , ProgramName(progname)
+{
+}
+
+Linker::~Linker() {
+  delete Composite;
+}
+
+bool
+Linker::error(const std::string& message) {
+  Error = message;
+  if (!(Flags&QuietErrors))
+    cerr << ProgramName << ": error: " << message << "\n";
+  return true;
+}
+
+bool
+Linker::warning(const std::string& message) {
+  Error = message;
+  if (!(Flags&QuietErrors))
+    cerr << ProgramName << ": warning: " << message << "\n";
+  return false;
+}
+
+void
+Linker::verbose(const std::string& message) {
+  if (Flags&Verbose)
+    cerr << "  " << message << "\n";
+}
+
+void
+Linker::addPath(const sys::Path& path) {
+  LibPaths.push_back(path);
+}
+
+void
+Linker::addPaths(const std::vector<std::string>& paths) {
+  for (unsigned i = 0; i != paths.size(); ++i) {
+    sys::Path aPath;
+    aPath.set(paths[i]);
+    LibPaths.push_back(aPath);
+  }
+}
+
+void
+Linker::addSystemPaths() {
+  sys::Path::GetBitcodeLibraryPaths(LibPaths);
+  LibPaths.insert(LibPaths.begin(),sys::Path("./"));
+}
+
+Module*
+Linker::releaseModule() {
+  Module* result = Composite;
+  LibPaths.clear();
+  Error.clear();
+  Composite = 0;
+  Flags = 0;
+  return result;
+}
+
+// LoadObject - Read in and parse the bitcode file named by FN and return the
+// module it contains (wrapped in an auto_ptr), or auto_ptr<Module>() and set
+// Error if an error occurs.
+std::auto_ptr<Module>
+Linker::LoadObject(const sys::Path &FN) {
+  std::string ParseErrorMessage;
+  Module *Result = 0;
+  
+  const std::string &FNS = FN.toString();
+  std::auto_ptr<MemoryBuffer> Buffer(
+                          MemoryBuffer::getFileOrSTDIN(&FNS[0], FNS.size()));
+  if (Buffer.get())
+    Result = ParseBitcodeFile(Buffer.get(), &ParseErrorMessage);
+  else
+    ParseErrorMessage = "Error reading file '" + FNS + "'";
+    
+  if (Result)
+    return std::auto_ptr<Module>(Result);
+  Error = "Bitcode file '" + FN.toString() + "' could not be loaded";
+  if (ParseErrorMessage.size())
+    Error += ": " + ParseErrorMessage;
+  return std::auto_ptr<Module>();
+}
+
+// IsLibrary - Determine if "Name" is a library in "Directory". Return
+// a non-empty sys::Path if its found, an empty one otherwise.
+static inline sys::Path IsLibrary(const std::string& Name,
+                                  const sys::Path& Directory) {
+
+  sys::Path FullPath(Directory);
+
+  // Try the libX.a form
+  FullPath.appendComponent("lib" + Name);
+  FullPath.appendSuffix("a");
+  if (FullPath.isArchive())
+    return FullPath;
+
+  // Try the libX.bca form
+  FullPath.eraseSuffix();
+  FullPath.appendSuffix("bca");
+  if (FullPath.isArchive())
+    return FullPath;
+
+  // Try the libX.so (or .dylib) form
+  FullPath.eraseSuffix();
+  FullPath.appendSuffix(&(LTDL_SHLIB_EXT[1]));
+  if (FullPath.isDynamicLibrary())  // Native shared library?
+    return FullPath;
+  if (FullPath.isBitcodeFile())    // .so file containing bitcode?
+    return FullPath;
+
+  // Not found .. fall through
+
+  // Indicate that the library was not found in the directory.
+  FullPath.clear();
+  return FullPath;
+}
+
+/// FindLib - Try to convert Filename into the name of a file that we can open,
+/// if it does not already name a file we can open, by first trying to open
+/// Filename, then libFilename.[suffix] for each of a set of several common
+/// library suffixes, in each of the directories in LibPaths. Returns an empty
+/// Path if no matching file can be found.
+///
+sys::Path
+Linker::FindLib(const std::string &Filename) {
+  // Determine if the pathname can be found as it stands.
+  sys::Path FilePath(Filename);
+  if (FilePath.canRead() &&
+      (FilePath.isArchive() || FilePath.isDynamicLibrary()))
+    return FilePath;
+
+  // Iterate over the directories in Paths to see if we can find the library
+  // there.
+  for (unsigned Index = 0; Index != LibPaths.size(); ++Index) {
+    sys::Path Directory(LibPaths[Index]);
+    sys::Path FullPath = IsLibrary(Filename,Directory);
+    if (!FullPath.isEmpty())
+      return FullPath;
+  }
+  return sys::Path();
+}