[Modules] Move GetElementPtrTypeIterator into the IR library. As its

name might indicate, it is an iterator over the types in an instruction
in the IR.... You see where this is going.

Another step of modularizing the support library.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202815 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 113 insertions, 0 deletions

diff --git a/include/llvm/IR/GetElementPtrTypeIterator.h b/include/llvm/IR/GetElementPtrTypeIterator.h
new file mode 100644
index 0000000000..f2722d6b0d
--- /dev/null
+++ b/include/llvm/IR/GetElementPtrTypeIterator.h
@@ -0,0 +1,113 @@
+//===- GetElementPtrTypeIterator.h ------------------------------*- 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 an iterator for walking through the types indexed by
+// getelementptr instructions.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_IR_GETELEMENTPTRTYPEITERATOR_H
+#define LLVM_IR_GETELEMENTPTRTYPEITERATOR_H
+
+#include "llvm/IR/DerivedTypes.h"
+#include "llvm/IR/User.h"
+
+namespace llvm {
+  template<typename ItTy = User::const_op_iterator>
+  class generic_gep_type_iterator
+    : public std::iterator<std::forward_iterator_tag, Type *, ptrdiff_t> {
+    typedef std::iterator<std::forward_iterator_tag,
+                          Type *, ptrdiff_t> super;
+
+    ItTy OpIt;
+    Type *CurTy;
+    generic_gep_type_iterator() {}
+  public:
+
+    static generic_gep_type_iterator begin(Type *Ty, ItTy It) {
+      generic_gep_type_iterator I;
+      I.CurTy = Ty;
+      I.OpIt = It;
+      return I;
+    }
+    static generic_gep_type_iterator end(ItTy It) {
+      generic_gep_type_iterator I;
+      I.CurTy = 0;
+      I.OpIt = It;
+      return I;
+    }
+
+    bool operator==(const generic_gep_type_iterator& x) const {
+      return OpIt == x.OpIt;
+    }
+    bool operator!=(const generic_gep_type_iterator& x) const {
+      return !operator==(x);
+    }
+
+    Type *operator*() const {
+      return CurTy;
+    }
+
+    Type *getIndexedType() const {
+      CompositeType *CT = cast<CompositeType>(CurTy);
+      return CT->getTypeAtIndex(getOperand());
+    }
+
+    // This is a non-standard operator->.  It allows you to call methods on the
+    // current type directly.
+    Type *operator->() const { return operator*(); }
+
+    Value *getOperand() const { return *OpIt; }
+
+    generic_gep_type_iterator& operator++() {   // Preincrement
+      if (CompositeType *CT = dyn_cast<CompositeType>(CurTy)) {
+        CurTy = CT->getTypeAtIndex(getOperand());
+      } else {
+        CurTy = 0;
+      }
+      ++OpIt;
+      return *this;
+    }
+
+    generic_gep_type_iterator operator++(int) { // Postincrement
+      generic_gep_type_iterator tmp = *this; ++*this; return tmp;
+    }
+  };
+
+  typedef generic_gep_type_iterator<> gep_type_iterator;
+
+  inline gep_type_iterator gep_type_begin(const User *GEP) {
+    return gep_type_iterator::begin
+      (GEP->getOperand(0)->getType()->getScalarType(), GEP->op_begin()+1);
+  }
+  inline gep_type_iterator gep_type_end(const User *GEP) {
+    return gep_type_iterator::end(GEP->op_end());
+  }
+  inline gep_type_iterator gep_type_begin(const User &GEP) {
+    return gep_type_iterator::begin
+      (GEP.getOperand(0)->getType()->getScalarType(), GEP.op_begin()+1);
+  }
+  inline gep_type_iterator gep_type_end(const User &GEP) {
+    return gep_type_iterator::end(GEP.op_end());
+  }
+
+  template<typename T>
+  inline generic_gep_type_iterator<const T *>
+  gep_type_begin(Type *Op0, ArrayRef<T> A) {
+    return generic_gep_type_iterator<const T *>::begin(Op0, A.begin());
+  }
+
+  template<typename T>
+  inline generic_gep_type_iterator<const T *>
+  gep_type_end(Type * /*Op0*/, ArrayRef<T> A) {
+    return generic_gep_type_iterator<const T *>::end(A.end());
+  }
+} // end namespace llvm
+
+#endif