Implement support for -fwritable-strings and make the code generator
merge string literals when it is not provided.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@44394 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CodeGen/CGExpr.cpp b/CodeGen/CGExpr.cpp
index b996eca..f9a00eb 100644
--- a/CodeGen/CGExpr.cpp
+++ b/CodeGen/CGExpr.cpp
@@ -304,18 +304,8 @@
   assert(!E->isWide() && "FIXME: Wide strings not supported yet!");
   const char *StrData = E->getStrData();
   unsigned Len = E->getByteLength();
-  
-  // FIXME: Can cache/reuse these within the module.
-  llvm::Constant *C=llvm::ConstantArray::get(std::string(StrData, StrData+Len));
-  
-  // Create a global variable for this.
-  C = new llvm::GlobalVariable(C->getType(), true, 
-                               llvm::GlobalValue::InternalLinkage,
-                               C, ".str", CurFn->getParent());
-  llvm::Constant *Zero = llvm::Constant::getNullValue(llvm::Type::Int32Ty);
-  llvm::Constant *Zeros[] = { Zero, Zero };
-  C = llvm::ConstantExpr::getGetElementPtr(C, Zeros, 2);
-  return LValue::MakeAddr(C);
+  std::string StringLiteral(StrData, StrData+Len);
+  return LValue::MakeAddr(CGM.GetAddrOfConstantString(StringLiteral));
 }
 
 LValue CodeGenFunction::EmitPreDefinedLValue(const PreDefinedExpr *E) {