Use forward declarations and move TargetELFWriterInfo impl to a new file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73209 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/TargetELFWriterInfo.cpp

@@ -0,0 +1,33 @@
+//===-- lib/Target/TargetELFWriterInfo.cpp - ELF Writer Info --0-*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the TargetELFWriterInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Function.h"
+#include "llvm/Target/TargetELFWriterInfo.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+using namespace llvm;
+
+TargetELFWriterInfo::TargetELFWriterInfo(TargetMachine &tm) : TM(tm) {}
+
+TargetELFWriterInfo::~TargetELFWriterInfo() {}
+
+/// getFunctionAlignment - Returns the alignment for function 'F', targets
+/// with different alignment constraints should overload this method
+unsigned TargetELFWriterInfo::getFunctionAlignment(const Function *F) const {
+  const TargetData *TD = TM.getTargetData();
+  unsigned FnAlign = F->getAlignment();
+  unsigned TDAlign = TD->getPointerABIAlignment();
+  unsigned Align = std::max(FnAlign, TDAlign);
+  assert(!(Align & (Align-1)) && "Alignment is not a power of two!");
+  return Align;
+}