New clone function routine

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2045 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Utils/CloneFunction.cpp b/lib/Transforms/Utils/CloneFunction.cpp
new file mode 100644 (file)
index 0000000..aa62797
--- /dev/null
+++ b/lib/Transforms/Utils/CloneFunction.cpp
@@ -0,0 +1,90 @@
+
+// FIXME: document
+
+#include "llvm/Transforms/CloneFunction.h"
+#include "llvm/Function.h"
+#include "llvm/BasicBlock.h"
+#include "llvm/Instruction.h"
+#include <map>
+
+// FIXME: This should be merged with MethodInlining
+
+// RemapInstruction - Convert the instruction operands from referencing the 
+// current values into those specified by ValueMap.
+//
+static inline void RemapInstruction(Instruction *I, 
+                                    std::map<const Value *, Value*> &ValueMap) {
+  for (unsigned op = 0, E = I->getNumOperands(); op != E; ++op) {
+    const Value *Op = I->getOperand(op);
+    Value *V = ValueMap[Op];
+    if (!V && (isa<GlobalValue>(Op) || isa<Constant>(Op)))
+      continue;  // Globals and constants don't get relocated
+
+#ifndef NDEBUG
+    if (!V) {
+      cerr << "Val = \n" << Op << "Addr = " << (void*)Op;
+      cerr << "\nInst = " << I;
+    }
+#endif
+    assert(V && "Referenced value not in value map!");
+    I->setOperand(op, V);
+  }
+}
+
+// Clone OldFunc into NewFunc, transforming the old arguments into references to
+// ArgMap values.
+//
+void CloneFunctionInto(Function *NewFunc, const Function *OldFunc,
+                       const std::vector<Value*> &ArgMap) {
+  assert(OldFunc->getArgumentList().empty() ||
+         !NewFunc->getArgumentList().empty() &&
+         "Synthesization of arguments is not implemented yet!");
+  assert(OldFunc->getArgumentList().size() == ArgMap.size() &&
+         "Improper number of argument values to map specified!");
+  
+  // Keep a mapping between the original function's values and the new
+  // duplicated code's values.  This includes all of: Function arguments,
+  // instruction values, constant pool entries, and basic blocks.
+  //
+  std::map<const Value *, Value*> ValueMap;
+
+  // Add all of the function arguments to the mapping...
+  for (unsigned i = 0, e = ArgMap.size(); i != e; ++i)
+    ValueMap[(Value*)OldFunc->getArgumentList()[i]] = ArgMap[i];
+
+
+  // Loop over all of the basic blocks in the function, cloning them as
+  // appropriate.
+  //
+  for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
+       BI != BE; ++BI) {
+    const BasicBlock *BB = *BI;
+    assert(BB->getTerminator() && "BasicBlock doesn't have terminator!?!?");
+    
+    // Create a new basic block to copy instructions into!
+    BasicBlock *CBB = new BasicBlock(BB->getName(), NewFunc);
+    ValueMap[BB] = CBB;                       // Add basic block mapping.
+
+    // Loop over all instructions copying them over...
+    for (BasicBlock::const_iterator II = BB->begin(), IE = BB->end();
+         II != IE; ++II) {
+      Instruction *NewInst = (*II)->clone();
+      NewInst->setName((*II)->getName());       // Name is not cloned...
+      CBB->getInstList().push_back(NewInst);
+      ValueMap[*II] = NewInst;                  // Add instruction map to value.
+    }
+  }
+
+  // Loop over all of the instructions in the function, fixing up operand 
+  // references as we go.  This uses ValueMap to do all the hard work.
+  //
+  for (Function::const_iterator BI = OldFunc->begin(), BE = OldFunc->end();
+       BI != BE; ++BI) {
+    const BasicBlock *BB = *BI;
+    BasicBlock *NBB = cast<BasicBlock>(ValueMap[BB]);
+    
+    // Loop over all instructions, fixing each one as we find it...
+    for (BasicBlock::iterator II = NBB->begin(); II != NBB->end(); II++)
+      RemapInstruction(*II, ValueMap);
+  }
+}