reapply the patches reverted in r149470 that reenable ConstantDataArray,

but with a critical fix to the SelectionDAG code that optimizes copies
from strings into immediate stores: the previous code was stopping reading
string data at the first nul.  Address this by adding a new argument to
llvm::getConstantStringInfo, preserving the behavior before the patch.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149800 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 91 insertions, 105 deletions

diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index f7884c6862..7d423c04a6 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -176,7 +176,7 @@ Constant *Constant::getAggregateElement(unsigned Elt) const {
     return UV->getElementValue(Elt);
   
   if (const ConstantDataSequential *CDS =dyn_cast<ConstantDataSequential>(this))
-    return CDS->getElementAsConstant(Elt);
+    return Elt < CDS->getNumElements() ? CDS->getElementAsConstant(Elt) : 0;
   return 0;
 }
 
@@ -666,6 +666,13 @@ UndefValue *UndefValue::getElementValue(unsigned Idx) const {
 //                            ConstantXXX Classes
 //===----------------------------------------------------------------------===//
 
+template <typename ItTy, typename EltTy>
+static bool rangeOnlyContains(ItTy Start, ItTy End, EltTy Elt) {
+  for (; Start != End; ++Start)
+    if (*Start != Elt)
+      return false;
+  return true;
+}
 
 ConstantArray::ConstantArray(ArrayType *T, ArrayRef<Constant *> V)
   : Constant(T, ConstantArrayVal,
@@ -680,54 +687,97 @@ ConstantArray::ConstantArray(ArrayType *T, ArrayRef<Constant *> V)
 }
 
 Constant *ConstantArray::get(ArrayType *Ty, ArrayRef<Constant*> V) {
+  // Empty arrays are canonicalized to ConstantAggregateZero.
+  if (V.empty())
+    return ConstantAggregateZero::get(Ty);
+
   for (unsigned i = 0, e = V.size(); i != e; ++i) {
     assert(V[i]->getType() == Ty->getElementType() &&
            "Wrong type in array element initializer");
   }
   LLVMContextImpl *pImpl = Ty->getContext().pImpl;
-  // If this is an all-zero array, return a ConstantAggregateZero object
-  bool isAllZero = true;
-  bool isUndef = false;
-  if (!V.empty()) {
-    Constant *C = V[0];
-    isAllZero = C->isNullValue();
-    isUndef = isa<UndefValue>(C);
-
-    if (isAllZero || isUndef)
-      for (unsigned i = 1, e = V.size(); i != e; ++i)
-        if (V[i] != C) {
-          isAllZero = false;
-          isUndef = false;
-          break;
-        }
-  }
-
-  if (isAllZero)
-    return ConstantAggregateZero::get(Ty);
-  if (isUndef)
+  
+  // If this is an all-zero array, return a ConstantAggregateZero object.  If
+  // all undef, return an UndefValue, if "all simple", then return a
+  // ConstantDataArray.
+  Constant *C = V[0];
+  if (isa<UndefValue>(C) && rangeOnlyContains(V.begin(), V.end(), C))
     return UndefValue::get(Ty);
-  return pImpl->ArrayConstants.getOrCreate(Ty, V);
-}
 
-/// ConstantArray::get(const string&) - Return an array that is initialized to
-/// contain the specified string.  If length is zero then a null terminator is 
-/// added to the specified string so that it may be used in a natural way. 
-/// Otherwise, the length parameter specifies how much of the string to use 
-/// and it won't be null terminated.
-///
-Constant *ConstantArray::get(LLVMContext &Context, StringRef Str,
-                             bool AddNull) {
-  SmallVector<Constant*, 8> ElementVals;
-  ElementVals.reserve(Str.size() + size_t(AddNull));
-  for (unsigned i = 0; i < Str.size(); ++i)
-    ElementVals.push_back(ConstantInt::get(Type::getInt8Ty(Context), Str[i]));
+  if (C->isNullValue() && rangeOnlyContains(V.begin(), V.end(), C))
+    return ConstantAggregateZero::get(Ty);
 
-  // Add a null terminator to the string...
-  if (AddNull)
-    ElementVals.push_back(ConstantInt::get(Type::getInt8Ty(Context), 0));
+  // Check to see if all of the elements are ConstantFP or ConstantInt and if
+  // the element type is compatible with ConstantDataVector.  If so, use it.
+  if (ConstantDataSequential::isElementTypeCompatible(C->getType())) {
+    // We speculatively build the elements here even if it turns out that there
+    // is a constantexpr or something else weird in the array, since it is so
+    // uncommon for that to happen.
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(C)) {
+      if (CI->getType()->isIntegerTy(8)) {
+        SmallVector<uint8_t, 16> Elts;
+        for (unsigned i = 0, e = V.size(); i != e; ++i)
+          if (ConstantInt *CI = dyn_cast<ConstantInt>(V[i]))
+            Elts.push_back(CI->getZExtValue());
+          else
+            break;
+        if (Elts.size() == V.size())
+          return ConstantDataArray::get(C->getContext(), Elts);
+      } else if (CI->getType()->isIntegerTy(16)) {
+        SmallVector<uint16_t, 16> Elts;
+        for (unsigned i = 0, e = V.size(); i != e; ++i)
+          if (ConstantInt *CI = dyn_cast<ConstantInt>(V[i]))
+            Elts.push_back(CI->getZExtValue());
+          else
+            break;
+        if (Elts.size() == V.size())
+          return ConstantDataArray::get(C->getContext(), Elts);
+      } else if (CI->getType()->isIntegerTy(32)) {
+        SmallVector<uint32_t, 16> Elts;
+        for (unsigned i = 0, e = V.size(); i != e; ++i)
+          if (ConstantInt *CI = dyn_cast<ConstantInt>(V[i]))
+            Elts.push_back(CI->getZExtValue());
+          else
+            break;
+        if (Elts.size() == V.size())
+          return ConstantDataArray::get(C->getContext(), Elts);
+      } else if (CI->getType()->isIntegerTy(64)) {
+        SmallVector<uint64_t, 16> Elts;
+        for (unsigned i = 0, e = V.size(); i != e; ++i)
+          if (ConstantInt *CI = dyn_cast<ConstantInt>(V[i]))
+            Elts.push_back(CI->getZExtValue());
+          else
+            break;
+        if (Elts.size() == V.size())
+          return ConstantDataArray::get(C->getContext(), Elts);
+      }
+    }
+    
+    if (ConstantFP *CFP = dyn_cast<ConstantFP>(C)) {
+      if (CFP->getType()->isFloatTy()) {
+        SmallVector<float, 16> Elts;
+        for (unsigned i = 0, e = V.size(); i != e; ++i)
+          if (ConstantFP *CFP = dyn_cast<ConstantFP>(V[i]))
+            Elts.push_back(CFP->getValueAPF().convertToFloat());
+          else
+            break;
+        if (Elts.size() == V.size())
+          return ConstantDataArray::get(C->getContext(), Elts);
+      } else if (CFP->getType()->isDoubleTy()) {
+        SmallVector<double, 16> Elts;
+        for (unsigned i = 0, e = V.size(); i != e; ++i)
+          if (ConstantFP *CFP = dyn_cast<ConstantFP>(V[i]))
+            Elts.push_back(CFP->getValueAPF().convertToDouble());
+          else
+            break;
+        if (Elts.size() == V.size())
+          return ConstantDataArray::get(C->getContext(), Elts);
+      }
+    }
+  }
 
-  ArrayType *ATy = ArrayType::get(Type::getInt8Ty(Context), ElementVals.size());
-  return get(ATy, ElementVals);
+  // Otherwise, we really do want to create a ConstantArray.
+  return pImpl->ArrayConstants.getOrCreate(Ty, V);
 }
 
 /// getTypeForElements - Return an anonymous struct type to use for a constant
@@ -839,8 +889,7 @@ Constant *ConstantVector::get(ArrayRef<Constant*> V) {
    
   // Check to see if all of the elements are ConstantFP or ConstantInt and if
   // the element type is compatible with ConstantDataVector.  If so, use it.
-  if (ConstantDataSequential::isElementTypeCompatible(C->getType()) &&
-      (isa<ConstantFP>(C) || isa<ConstantInt>(C))) {
+  if (ConstantDataSequential::isElementTypeCompatible(C->getType())) {
     // We speculatively build the elements here even if it turns out that there
     // is a constantexpr or something else weird in the array, since it is so
     // uncommon for that to happen.
@@ -1146,69 +1195,6 @@ void ConstantArray::destroyConstant() {
   destroyConstantImpl();
 }
 
-/// isString - This method returns true if the array is an array of i8, and 
-/// if the elements of the array are all ConstantInt's.
-bool ConstantArray::isString() const {
-  // Check the element type for i8...
-  if (!getType()->getElementType()->isIntegerTy(8))
-    return false;
-  // Check the elements to make sure they are all integers, not constant
-  // expressions.
-  for (unsigned i = 0, e = getNumOperands(); i != e; ++i)
-    if (!isa<ConstantInt>(getOperand(i)))
-      return false;
-  return true;
-}
-
-/// isCString - This method returns true if the array is a string (see
-/// isString) and it ends in a null byte \\0 and does not contains any other
-/// null bytes except its terminator.
-bool ConstantArray::isCString() const {
-  // Check the element type for i8...
-  if (!getType()->getElementType()->isIntegerTy(8))
-    return false;
-
-  // Last element must be a null.
-  if (!getOperand(getNumOperands()-1)->isNullValue())
-    return false;
-  // Other elements must be non-null integers.
-  for (unsigned i = 0, e = getNumOperands()-1; i != e; ++i) {
-    if (!isa<ConstantInt>(getOperand(i)))
-      return false;
-    if (getOperand(i)->isNullValue())
-      return false;
-  }
-  return true;
-}
-
-
-/// convertToString - Helper function for getAsString() and getAsCString().
-static std::string convertToString(const User *U, unsigned len) {
-  std::string Result;
-  Result.reserve(len);
-  for (unsigned i = 0; i != len; ++i)
-    Result.push_back((char)cast<ConstantInt>(U->getOperand(i))->getZExtValue());
-  return Result;
-}
-
-/// getAsString - If this array is isString(), then this method converts the
-/// array to an std::string and returns it.  Otherwise, it asserts out.
-///
-std::string ConstantArray::getAsString() const {
-  assert(isString() && "Not a string!");
-  return convertToString(this, getNumOperands());
-}
-
-
-/// getAsCString - If this array is isCString(), then this method converts the
-/// array (without the trailing null byte) to an std::string and returns it.
-/// Otherwise, it asserts out.
-///
-std::string ConstantArray::getAsCString() const {
-  assert(isCString() && "Not a string!");
-  return convertToString(this, getNumOperands() - 1);
-}
-
 
 //---- ConstantStruct::get() implementation...
 //