1 files changed, 84 insertions, 0 deletions
diff --git a/lld/lib/Passes/OrderPass.cpp b/lld/lib/Passes/OrderPass.cpp
new file mode 100644
index 00000000000..60d52682267
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+++ b/lld/lib/Passes/OrderPass.cpp
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+//===- Passes/OrderPass.cpp - sort atoms ----------------------------------===//
+//
+//                             The LLVM Linker
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This linker pass sorts atoms.  By default atoms are sort first by the
+// order their .o files were found on the command line, then by order of the
+// atoms (address) in the .o file.  But some atoms have a prefered location
+// in their section (such as pinned to the start or end of the section), so
+// the sort must take that into account too.
+//
+//===----------------------------------------------------------------------===//
+
+
+#include "lld/Core/DefinedAtom.h"
+#include "lld/Core/File.h"
+#include "lld/Core/LLVM.h"
+#include "lld/Core/Pass.h"
+#include "lld/Core/Reference.h"
+#include "llvm/ADT/DenseMap.h"
+
+
+namespace lld {
+
+static bool compare(const DefinedAtom *left, const DefinedAtom *right) {
+  if ( left == right )
+    return false;
+
+  // Sort same permissions together.
+  DefinedAtom::ContentPermissions leftPerms  = left->permissions();
+  DefinedAtom::ContentPermissions rightPerms = right->permissions();
+  if (leftPerms != rightPerms) 
+		return leftPerms < rightPerms;
+
+  
+  // Sort same content types together.
+  DefinedAtom::ContentType leftType  = left->contentType();
+  DefinedAtom::ContentType rightType = right->contentType();
+  if (leftType != rightType) 
+		return leftType < rightType;
+
+
+  // TO DO: Sort atoms in customs sections together.
+
+
+  // Sort by section position preference.
+  DefinedAtom::SectionPosition leftPos  = left->sectionPosition();
+  DefinedAtom::SectionPosition rightPos = right->sectionPosition();
+  bool leftSpecialPos  = (leftPos  != DefinedAtom::sectionPositionAny); 
+  bool rightSpecialPos = (rightPos != DefinedAtom::sectionPositionAny); 
+  if (leftSpecialPos || rightSpecialPos) {
+    if (leftPos != rightPos)
+      return leftPos < rightPos;
+  }
+  
+  // Sort by .o order.
+  const File *leftFile  = &left->file();
+  const File *rightFile = &right->file();
+  if ( leftFile != rightFile ) 
+		return leftFile->ordinal() < rightFile->ordinal();
+  
+  // Sort by atom order with .o file.
+  uint64_t leftOrdinal  = left->ordinal();
+  uint64_t rightOrdinal = right->ordinal();
+  if ( leftOrdinal != rightOrdinal ) 
+		return leftOrdinal < rightOrdinal;
+ 
+  return false;
+}
+
+
+
+void OrderPass::perform(MutableFile &mergedFile) {
+
+  MutableFile::DefinedAtomRange atomRange = mergedFile.definedAtoms();
+  
+  std::sort(atomRange.begin(), atomRange.end(), compare);
+}
+
+} // namespace