C++, CBE, and TLOF support for ConstantDataSequential

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148805 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 125 insertions, 20 deletions

diff --git a/lib/Target/CBackend/CBackend.cpp b/lib/Target/CBackend/CBackend.cpp
index f4eb14a8b8..4b86ee4d31 100644
--- a/lib/Target/CBackend/CBackend.cpp
+++ b/lib/Target/CBackend/CBackend.cpp
@@ -215,6 +215,8 @@ namespace {
     bool printConstExprCast(const ConstantExpr *CE, bool Static);
     void printConstantArray(ConstantArray *CPA, bool Static);
     void printConstantVector(ConstantVector *CV, bool Static);
+    void printConstantDataSequential(ConstantDataSequential *CDS, bool Static);
+
 
     /// isAddressExposed - Return true if the specified value's name needs to
     /// have its address taken in order to get a C value of the correct type.
@@ -556,20 +558,10 @@ raw_ostream &CWriter::printType(raw_ostream &Out, Type *Ty,
 }
 
 void CWriter::printConstantArray(ConstantArray *CPA, bool Static) {
-
   // As a special case, print the array as a string if it is an array of
   // ubytes or an array of sbytes with positive values.
   //
-  Type *ETy = CPA->getType()->getElementType();
-  bool isString = (ETy == Type::getInt8Ty(CPA->getContext()) ||
-                   ETy == Type::getInt8Ty(CPA->getContext()));
-
-  // Make sure the last character is a null char, as automatically added by C
-  if (isString && (CPA->getNumOperands() == 0 ||
-                   !cast<Constant>(*(CPA->op_end()-1))->isNullValue()))
-    isString = false;
-
-  if (isString) {
+  if (CPA->isCString()) {
     Out << '\"';
     // Keep track of whether the last number was a hexadecimal escape.
     bool LastWasHex = false;
@@ -637,6 +629,66 @@ void CWriter::printConstantVector(ConstantVector *CP, bool Static) {
   Out << " }";
 }
 
+void CWriter::printConstantDataSequential(ConstantDataSequential *CDS,
+                                          bool Static) {
+  // As a special case, print the array as a string if it is an array of
+  // ubytes or an array of sbytes with positive values.
+  //
+  if (CDS->isCString()) {
+    Out << '\"';
+    // Keep track of whether the last number was a hexadecimal escape.
+    bool LastWasHex = false;
+    
+    StringRef Bytes = CDS->getAsCString();
+    
+    // Do not include the last character, which we know is null
+    for (unsigned i = 0, e = Bytes.size(); i != e; ++i) {
+      unsigned char C = Bytes[i];
+      
+      // Print it out literally if it is a printable character.  The only thing
+      // to be careful about is when the last letter output was a hex escape
+      // code, in which case we have to be careful not to print out hex digits
+      // explicitly (the C compiler thinks it is a continuation of the previous
+      // character, sheesh...)
+      //
+      if (isprint(C) && (!LastWasHex || !isxdigit(C))) {
+        LastWasHex = false;
+        if (C == '"' || C == '\\')
+          Out << "\\" << (char)C;
+        else
+          Out << (char)C;
+      } else {
+        LastWasHex = false;
+        switch (C) {
+          case '\n': Out << "\\n"; break;
+          case '\t': Out << "\\t"; break;
+          case '\r': Out << "\\r"; break;
+          case '\v': Out << "\\v"; break;
+          case '\a': Out << "\\a"; break;
+          case '\"': Out << "\\\""; break;
+          case '\'': Out << "\\\'"; break;
+          default:
+            Out << "\\x";
+            Out << (char)(( C/16  < 10) ? ( C/16 +'0') : ( C/16 -10+'A'));
+            Out << (char)(((C&15) < 10) ? ((C&15)+'0') : ((C&15)-10+'A'));
+            LastWasHex = true;
+            break;
+        }
+      }
+    }
+    Out << '\"';
+  } else {
+    Out << "{ ";
+    printConstant(CDS->getElementAsConstant(0), Static);
+    for (unsigned i = 1, e = CDS->getNumOperands(); i != e; ++i) {
+      Out << ", ";
+      printConstant(CDS->getElementAsConstant(i), Static);
+    }
+    Out << " }";
+  }
+}
+
+
 // isFPCSafeToPrint - Returns true if we may assume that CFP may be written out
 // textually as a double (rather than as a reference to a stack-allocated
 // variable). We decide this by converting CFP to a string and back into a
@@ -1024,6 +1076,9 @@ void CWriter::printConstant(Constant *CPV, bool Static) {
     Out << "{ "; // Arrays are wrapped in struct types.
     if (ConstantArray *CA = dyn_cast<ConstantArray>(CPV)) {
       printConstantArray(CA, Static);
+    } else if (ConstantDataSequential *CDS = 
+                 dyn_cast<ConstantDataSequential>(CPV)) {
+      printConstantDataSequential(CDS, Static);
     } else {
       assert(isa<ConstantAggregateZero>(CPV) || isa<UndefValue>(CPV));
       ArrayType *AT = cast<ArrayType>(CPV->getType());
@@ -1051,6 +1106,9 @@ void CWriter::printConstant(Constant *CPV, bool Static) {
     }
     if (ConstantVector *CV = dyn_cast<ConstantVector>(CPV)) {
       printConstantVector(CV, Static);
+    } else if (ConstantDataSequential *CDS = 
+               dyn_cast<ConstantDataSequential>(CPV)) {
+      printConstantDataSequential(CDS, Static);
     } else {
       assert(isa<ConstantAggregateZero>(CPV) || isa<UndefValue>(CPV));
       VectorType *VT = cast<VectorType>(CPV->getType());
diff --git a/lib/Target/CppBackend/CPPBackend.cpp b/lib/Target/CppBackend/CPPBackend.cpp
index 25e675b8f4..de73a72ac4 100644
--- a/lib/Target/CppBackend/CPPBackend.cpp
+++ b/lib/Target/CppBackend/CPPBackend.cpp
@@ -698,9 +698,7 @@ void CppWriter::printConstant(const Constant *CV) {
     printCFP(CFP);
     Out << ";";
   } else if (const ConstantArray *CA = dyn_cast<ConstantArray>(CV)) {
-    if (CA->isString() &&
-        CA->getType()->getElementType() ==
-            Type::getInt8Ty(CA->getContext())) {
+    if (CA->isString()) {
       Out << "Constant* " << constName <<
              " = ConstantArray::get(mod->getContext(), \"";
       std::string tmp = CA->getAsString();
@@ -757,6 +755,41 @@ void CppWriter::printConstant(const Constant *CV) {
   } else if (isa<UndefValue>(CV)) {
     Out << "UndefValue* " << constName << " = UndefValue::get("
         << typeName << ");";
+  } else if (const ConstantDataSequential *CDS =
+               dyn_cast<ConstantDataSequential>(CV)) {
+    if (CDS->isString()) {
+      Out << "Constant *" << constName <<
+      " = ConstantDataArray::getString(mod->getContext(), \"";
+      StringRef Str = CA->getAsString();
+      bool nullTerminate = false;
+      if (Str.back() == 0) {
+        Str = Str.drop_back();
+        nullTerminate = true;
+      }
+      printEscapedString(Str);
+      // Determine if we want null termination or not.
+      if (nullTerminate)
+        Out << "\", true);";
+      else
+        Out << "\", false);";// No null terminator
+    } else {
+      // TODO: Could generate more efficient code generating CDS calls instead.
+      Out << "std::vector<Constant*> " << constName << "_elems;";
+      nl(Out);
+      for (unsigned i = 0; i != CDS->getNumElements(); ++i) {
+        Constant *Elt = CDS->getElementAsConstant(i);
+        printConstant(Elt);
+        Out << constName << "_elems.push_back(" << getCppName(Elt) << ");";
+        nl(Out);
+      }
+      Out << "Constant* " << constName;
+      
+      if (isa<ArrayType>(CDS->getType()))
+        Out << " = ConstantArray::get(";
+      else
+        Out << " = ConstantVector::get(";
+      Out << typeName << ", " << constName << "_elems);";
+    }
   } else if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(CV)) {
     if (CE->getOpcode() == Instruction::GetElementPtr) {
       Out << "std::vector<Constant*> " << constName << "_indices;";
diff --git a/lib/Target/TargetLoweringObjectFile.cpp b/lib/Target/TargetLoweringObjectFile.cpp
index 70abe5a052..ec3b1946f3 100644
--- a/lib/Target/TargetLoweringObjectFile.cpp
+++ b/lib/Target/TargetLoweringObjectFile.cpp
@@ -73,12 +73,12 @@ static bool isSuitableForBSS(const GlobalVariable *GV, bool NoZerosInBSS) {
 
 /// IsNullTerminatedString - Return true if the specified constant (which is
 /// known to have a type that is an array of 1/2/4 byte elements) ends with a
-/// nul value and contains no other nuls in it.
+/// nul value and contains no other nuls in it.  Note that this is more general
+/// than ConstantDataSequential::isString because we allow 2 & 4 byte strings.
 static bool IsNullTerminatedString(const Constant *C) {
-  ArrayType *ATy = cast<ArrayType>(C->getType());
-
-  // First check: is we have constant array of i8 terminated with zero
+  // First check: is we have constant array terminated with zero
   if (const ConstantArray *CVA = dyn_cast<ConstantArray>(C)) {
+    ArrayType *ATy = cast<ArrayType>(C->getType());
     if (ATy->getNumElements() == 0) return false;
 
     ConstantInt *Null =
@@ -94,10 +94,23 @@ static bool IsNullTerminatedString(const Constant *C) {
         return false;
     return true;
   }
+  if (const ConstantDataSequential *CDS = dyn_cast<ConstantDataSequential>(C)) {
+    unsigned NumElts = CDS->getNumElements();
+    assert(NumElts != 0 && "Can't have an empty CDS");
+    
+    if (CDS->getElementAsInteger(NumElts-1) != 0)
+      return false; // Not null terminated.
+    
+    // Verify that the null doesn't occur anywhere else in the string.
+    for (unsigned i = 0; i != NumElts-1; ++i)
+      if (CDS->getElementAsInteger(i) == 0)
+        return false;
+    return true;
+  }
 
   // Another possibility: [1 x i8] zeroinitializer
   if (isa<ConstantAggregateZero>(C))
-    return ATy->getNumElements() == 1;
+    return cast<ArrayType>(C->getType())->getNumElements() == 1;
 
   return false;
 }
diff --git a/lib/VMCore/Constants.cpp b/lib/VMCore/Constants.cpp
index 5151105e05..1976832294 100644
--- a/lib/VMCore/Constants.cpp
+++ b/lib/VMCore/Constants.cpp
@@ -2048,7 +2048,8 @@ static bool isAllZeros(StringRef Arr) {
 /// we *want* an underlying "char*" to avoid TBAA type punning violations.
 Constant *ConstantDataSequential::getImpl(StringRef Elements, Type *Ty) {
   assert(isElementTypeCompatible(cast<SequentialType>(Ty)->getElementType()));
-  // If the elements are all zero, return a CAZ, which is more dense.
+  // If the elements are all zero or there are no elements, return a CAZ, which
+  // is more dense and canonical.
   if (isAllZeros(Elements))
     return ConstantAggregateZero::get(Ty);