Utility routines for simpler access to the value of an integer constant.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236 91177308-0d34-0410-b5e6-96231b3b80d8

lib/VMCore/ConstPoolVals.cpp

@@ -0,0 +1,108 @@
+//===-- llvm/ConstPoolVals.cpp - Implement Constant Value nodes -*- C++ -*--=//
+//
+// This file implements the ConstPoolVal class and associated functions.
+//
+//===---------------------------------------------------------------------===//
+
+#include "llvm/Type.h"
+#include "llvm/Value.h"
+#include "llvm/ConstPoolVals.h"
+
+
+//===--------------------------------------------------------------------------
+// External functions
+//
+
+// Convenience functions to get the value of an integer constant, for an
+// appropriate integer or non-integer type that can be held in an integer.
+// The type of the argument must be the following:
+//   GetSignedIntConstantValue:   signed integer or bool
+//   GetUnsignedIntConstantValue: unsigned integer, bool, or pointer
+//   GetConstantValueAsSignedInt: any of the above, but the value
+//				  must fit into a int64_t.
+// 
+// isValidConstant is set to true if a valid constant was found.
+// 
+
+int64_t
+GetSignedIntConstantValue(const Value* val, bool& isValidConstant)
+{
+  int64_t intValue = 0;
+  isValidConstant = false;
+  
+  if (val->getValueType() == Value::ConstantVal)
+    {
+      switch(val->getType()->getPrimitiveID())
+	{
+	case Type::BoolTyID:
+	  intValue = ((ConstPoolBool*) val)->getValue()? 1 : 0;
+	  isValidConstant = true;
+	  break;
+	case Type::SByteTyID:
+	case Type::ShortTyID:
+	case Type::IntTyID:
+	case Type::LongTyID:
+	  intValue = ((ConstPoolSInt*) val)->getValue();
+	  isValidConstant = true;
+	  break;
+	default:
+	  break;
+	}
+    }
+  
+  return intValue;
+}
+
+uint64_t
+GetUnsignedIntConstantValue(const Value* val, bool& isValidConstant)
+{
+  uint64_t intValue = 0;
+  isValidConstant = false;
+  
+  if (val->getValueType() == Value::ConstantVal)
+    {
+      switch(val->getType()->getPrimitiveID())
+	{
+	case Type::BoolTyID:
+	  intValue = ((ConstPoolBool*) val)->getValue()? 1 : 0;
+	  isValidConstant = true;
+	  break;
+	case Type::UByteTyID:
+	case Type::UShortTyID:
+	case Type::UIntTyID:
+	case Type::ULongTyID:
+	case Type::PointerTyID:
+	  intValue = ((ConstPoolUInt*) val)->getValue();
+	  isValidConstant = true;
+	  break;
+	default:
+	  break;
+	}
+    }
+  
+  return intValue;
+}
+
+
+int64_t
+GetConstantValueAsSignedInt(const Value* val, bool& isValidConstant)
+{
+  int64_t intValue = 0;
+  
+  if (val->getType()->isSigned())
+    {
+      intValue = GetSignedIntConstantValue(val, isValidConstant);
+    }
+  else				// non-numeric types will fall here
+    {
+      uint64_t uintValue = GetUnsignedIntConstantValue(val, isValidConstant);
+      if (isValidConstant && uintValue < INT64_MAX)	// then safe to cast to signed
+	intValue = (int64_t) uintValue;
+      else 
+	isValidConstant = false;
+    }
+  
+  return intValue;
+}
+
+//===--------------------------------------------------------------------------