1 files changed, 41 insertions, 1 deletions

diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 7a08b5fb8f..b9976a7207 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -2658,4 +2658,44 @@ void ConstantExpr::replaceUsesOfWithOnConstant(Value *From, Value *ToV,
   
   // Delete the old constant!
   destroyConstant();
-}
\ No newline at end of file
+}
+
+
+/// getStringValue - Turn an LLVM constant pointer that eventually points to a
+/// global into a string value.  Return an empty string if we can't do it.
+/// Parameter Chop determines if the result is chopped at the first null
+/// terminator.
+///
+std::string Constant::getStringValue(bool Chop, unsigned Offset) {
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(this)) {
+    if (GV->hasInitializer() && isa<ConstantArray>(GV->getInitializer())) {
+      ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
+      if (Init->isString()) {
+        std::string Result = Init->getAsString();
+        if (Offset < Result.size()) {
+          // If we are pointing INTO The string, erase the beginning...
+          Result.erase(Result.begin(), Result.begin()+Offset);
+
+          // Take off the null terminator, and any string fragments after it.
+          if (Chop) {
+            std::string::size_type NullPos = Result.find_first_of((char)0);
+            if (NullPos != std::string::npos)
+              Result.erase(Result.begin()+NullPos, Result.end());
+          }
+          return Result;
+        }
+      }
+    }
+  } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(this)) {
+    if (CE->getOpcode() == Instruction::GetElementPtr) {
+      // Turn a gep into the specified offset.
+      if (CE->getNumOperands() == 3 &&
+          cast<Constant>(CE->getOperand(1))->isNullValue() &&
+          isa<ConstantInt>(CE->getOperand(2))) {
+        Offset += cast<ConstantInt>(CE->getOperand(2))->getZExtValue();
+        return CE->getOperand(0)->getStringValue(Chop, Offset);
+      }
+    }
+  }
+  return "";
+}