NEw file

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@478 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/ConstantsScanner.h

@@ -0,0 +1,83 @@
+//==-- llvm/Analysis/ConstantsScanner.h - Iterate over constants -*- C++ -*-==//
+//
+// This class implements an iterator to walk through the constants referenced by
+// a method.  This is used by the Bytecode & Assembly writers to build constant
+// pools.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_CONSTANTSSCANNER_H
+#define LLVM_ANALYSIS_CONSTANTSSCANNER_H
+
+#include "llvm/Method.h"
+#include "llvm/Instruction.h"
+#include <iterator>
+class ConstPoolVal;
+
+class constant_iterator
+  : public std::forward_iterator<const ConstPoolVal, ptrdiff_t> {
+  Method::inst_const_iterator InstI;        // Method instruction iterator
+  unsigned OpIdx;                           // Operand index
+
+  typedef constant_iterator _Self;
+
+  inline bool isAtConstant() const {
+    assert(!InstI.atEnd() && OpIdx < InstI->getNumOperands() &&
+	   "isAtConstant called with invalid arguments!");
+    return InstI->getOperand(OpIdx)->isConstant();
+  }
+
+public:
+  inline constant_iterator(const Method *M) : InstI(M->inst_begin()), OpIdx(0) {
+    // Advance to first constant... if we are not already at constant or end
+    if (InstI != M->inst_end() &&                          // InstI is valid?
+	(InstI->getNumOperands() == 0 || !isAtConstant())) // Not at constant?
+      operator++();
+  }
+
+  inline constant_iterator(const Method *M, bool)   // end ctor
+    : InstI(M->inst_end()), OpIdx(0) {
+  }
+
+  inline bool operator==(const _Self& x) const { return OpIdx == x.OpIdx && 
+						        InstI == x.InstI; }
+  inline bool operator!=(const _Self& x) const { return !operator==(x); }
+
+  inline pointer operator*() const {
+    assert(isAtConstant() && "Dereferenced an iterator at the end!");
+    return InstI->getOperand(OpIdx)->castConstantAsserting();
+  }
+  inline pointer operator->() const { return operator*(); }
+
+  inline _Self& operator++() {   // Preincrement implementation
+    ++OpIdx;
+    do {
+      unsigned NumOperands = InstI->getNumOperands();
+      while (OpIdx < NumOperands && !isAtConstant()) {
+	++OpIdx;
+      }
+
+      if (OpIdx < NumOperands) return *this;  // Found a constant!
+      ++InstI;
+      OpIdx = 0;
+    } while (!InstI.atEnd());
+
+    return *this;  // At the end of the method
+  }
+
+  inline _Self operator++(int) { // Postincrement
+    _Self tmp = *this; ++*this; return tmp; 
+  }
+
+  inline bool atEnd() const { return InstI.atEnd(); }
+};
+
+inline constant_iterator constant_begin(const Method *M) {
+  return constant_iterator(M);
+}
+
+inline constant_iterator constant_end(const Method *M) {
+  return constant_iterator(M, true);
+}
+
+#endif