Initial checkin of Module cloning support stuff

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4788 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/CloneModule.cpp

@@ -0,0 +1,73 @@
+//===- CloneModule.cpp - Clone an entire module ---------------------------===//
+//
+// This file implements the CloneModule interface which makes a copy of an
+// entire module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Module.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Constant.h"
+#include "ValueMapper.h"
+
+/// CloneModule - Return an exact copy of the specified module.  This is not as
+/// easy as it might seem because we have to worry about making copies of global
+/// variables and functions, and making their (intializers and references,
+/// respectively) refer to the right globals.
+///
+Module *CloneModule(const Module *M) {
+  // First off, we need to create the new module...
+  Module *New = new Module();
+
+  // Create the value map that maps things from the old module over to the new
+  // module.
+  std::map<const Value*, Value*> ValueMap;
+
+  // Loop over all of the global variables, making corresponding globals in the
+  // new module.  Here we add them to the ValueMap and to the new Module.  We
+  // don't worry about attributes or initializers, they will come later.
+  //
+  for (Module::const_giterator I = M->gbegin(), E = M->gend(); I != E; ++I)
+    ValueMap[I] = new GlobalVariable(I->getType()->getElementType(),
+                                     false, false, 0, I->getName(), New);
+
+  // Loop over the functions in the module, making external functions as before
+  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I)
+    ValueMap[I]=new Function(cast<FunctionType>(I->getType()->getElementType()),
+                             false, I->getName(), New);
+
+  // Now that all of the things that global variable initializer can refer to
+  // have been created, loop through and copy the global variable referrers
+  // over...  We also set the attributes on the global now.
+  //
+  for (Module::const_giterator I = M->gbegin(), E = M->gend(); I != E; ++I) {
+    GlobalVariable *GV = cast<GlobalVariable>(ValueMap[I]);
+    if (I->hasInitializer())
+      GV->setInitializer(cast<Constant>(MapValue(I->getInitializer(),
+                                                 ValueMap)));
+    if (I->hasInternalLinkage())
+      GV->setInternalLinkage(true);
+  }
+
+  // Similarly, copy over function bodies now...
+  //
+  for (Module::const_iterator I = M->begin(), E = M->end(); I != E; ++I) {
+    Function *F = cast<Function>(ValueMap[I]);
+    if (!I->isExternal()) {
+      Function::aiterator DestI = F->abegin();
+      for (Function::const_aiterator J = I->abegin(); J != I->aend(); ++J) {
+        DestI->setName(J->getName());
+        ValueMap[J] = DestI++;
+      }
+
+      std::vector<ReturnInst*> Returns;  // Ignore returns cloned...
+      CloneFunctionInto(F, I, ValueMap, Returns);
+    }
+
+    if (I->hasInternalLinkage())
+      F->setInternalLinkage(true);
+  }
+
+  return New;
+}