Implement emitGlobalConstant

llvm-svn: 15868

lib/CodeGen/AsmPrinter.cpp

@@ -108,3 +108,164 @@ void AsmPrinter::emitConstantValueOnly(const Constant *CV) {
     assert(0 && "Unknown constant value!");
   }
 }
+
+/// toOctal - Convert the low order bits of X into an octal digit.
+///
+static inline char toOctal(int X) {
+  return (X&7)+'0';
+}
+
+/// getAsCString - Return the specified array as a C compatible string, only if
+/// the predicate isString is true.
+///
+static void printAsCString(std::ostream &O, const ConstantArray *CVA) {
+  assert(CVA->isString() && "Array is not string compatible!");
+
+  O << "\"";
+  for (unsigned i = 0; i != CVA->getNumOperands(); ++i) {
+    unsigned char C = cast<ConstantInt>(CVA->getOperand(i))->getRawValue();
+
+    if (C == '"') {
+      O << "\\\"";
+    } else if (C == '\\') {
+      O << "\\\\";
+    } else if (isprint(C)) {
+      O << C;
+    } else {
+      switch(C) {
+      case '\b': O << "\\b"; break;
+      case '\f': O << "\\f"; break;
+      case '\n': O << "\\n"; break;
+      case '\r': O << "\\r"; break;
+      case '\t': O << "\\t"; break;
+      default:
+        O << '\\';
+        O << toOctal(C >> 6);
+        O << toOctal(C >> 3);
+        O << toOctal(C >> 0);
+        break;
+      }
+    }
+  }
+  O << "\"";
+}
+
+/// emitGlobalConstant - Print a general LLVM constant to the .s file.
+///
+void AsmPrinter::emitGlobalConstant(const Constant *CV) {  
+  const TargetData &TD = TM.getTargetData();
+
+  if (CV->isNullValue()) {
+    O << ZeroDirective << TD.getTypeSize(CV->getType()) << "\n";
+    return;
+  } else if (const ConstantArray *CVA = dyn_cast<ConstantArray>(CV)) {
+    if (CVA->isString()) {
+      O << AsciiDirective;
+      printAsCString(O, CVA);
+      O << "\n";
+    } else { // Not a string.  Print the values in successive locations
+      for (unsigned i = 0, e = CVA->getNumOperands(); i != e; ++i)
+        emitGlobalConstant(CVA->getOperand(i));
+    }
+    return;
+  } else if (const ConstantStruct *CVS = dyn_cast<ConstantStruct>(CV)) {
+    // Print the fields in successive locations. Pad to align if needed!
+    const StructLayout *cvsLayout = TD.getStructLayout(CVS->getType());
+    unsigned sizeSoFar = 0;
+    for (unsigned i = 0, e = CVS->getNumOperands(); i != e; ++i) {
+      const Constant* field = CVS->getOperand(i);
+
+      // Check if padding is needed and insert one or more 0s.
+      unsigned fieldSize = TD.getTypeSize(field->getType());
+      unsigned padSize = ((i == e-1? cvsLayout->StructSize
+                           : cvsLayout->MemberOffsets[i+1])
+                          - cvsLayout->MemberOffsets[i]) - fieldSize;
+      sizeSoFar += fieldSize + padSize;
+
+      // Now print the actual field value
+      emitGlobalConstant(field);
+
+      // Insert the field padding unless it's zero bytes...
+      if (padSize)
+        O << ZeroDirective << padSize << "\n";      
+    }
+    assert(sizeSoFar == cvsLayout->StructSize &&
+           "Layout of constant struct may be incorrect!");
+    return;
+  } else if (const ConstantFP *CFP = dyn_cast<ConstantFP>(CV)) {
+    // FP Constants are printed as integer constants to avoid losing
+    // precision...
+    double Val = CFP->getValue();
+    if (CFP->getType() == Type::DoubleTy) {
+      union DU {                            // Abide by C TBAA rules
+        double FVal;
+        uint64_t UVal;
+      } U;
+      U.FVal = Val;
+
+      if (TD.isBigEndian()) {
+        O << Data32bitsDirective << unsigned(U.UVal >> 32)
+          << "\t; double most significant word " << Val << "\n";
+        O << Data32bitsDirective << unsigned(U.UVal)
+          << "\t; double least significant word " << Val << "\n";
+      } else {
+        O << Data32bitsDirective << unsigned(U.UVal)
+          << "\t; double least significant word " << Val << "\n";
+        O << Data32bitsDirective << unsigned(U.UVal >> 32)
+          << "\t; double most significant word " << Val << "\n";
+      }
+      return;
+    } else {
+      union FU {                            // Abide by C TBAA rules
+        float FVal;
+        int32_t UVal;
+      } U;
+      U.FVal = Val;
+      
+      O << Data32bitsDirective << U.UVal << "\t; float " << Val << "\n";
+      return;
+    }
+  } else if (CV->getType() == Type::ULongTy || CV->getType() == Type::LongTy) {
+    if (const ConstantInt *CI = dyn_cast<ConstantInt>(CV)) {
+      uint64_t Val = CI->getRawValue();
+        
+      if (TD.isBigEndian()) {
+        O << Data32bitsDirective << unsigned(Val >> 32)
+          << "\t; Double-word most significant word " << Val << "\n";
+        O << Data32bitsDirective << unsigned(Val)
+          << "\t; Double-word least significant word " << Val << "\n";
+      } else {
+        O << Data32bitsDirective << unsigned(Val)
+          << "\t; Double-word least significant word " << Val << "\n";
+        O << Data32bitsDirective << unsigned(Val >> 32)
+          << "\t; Double-word most significant word " << Val << "\n";
+      }
+      return;
+    }
+  }
+
+  const Type *type = CV->getType();
+  O << "\t";
+  switch (type->getTypeID()) {
+  case Type::UByteTyID: case Type::SByteTyID:
+    O << Data8bitsDirective;
+    break;
+  case Type::UShortTyID: case Type::ShortTyID:
+    O << Data16bitsDirective;
+    break;
+  case Type::BoolTyID: 
+  case Type::PointerTyID:
+  case Type::UIntTyID: case Type::IntTyID:
+    O << Data32bitsDirective;
+    break;
+  case Type::ULongTyID: case Type::LongTyID:    
+    assert (0 && "Should have already output double-word constant.");
+  case Type::FloatTyID: case Type::DoubleTyID:
+    assert (0 && "Should have already output floating point constant.");
+  default:
+    assert (0 && "Can't handle printing this type of thing");
+    break;
+  }
+  emitConstantValueOnly(CV);
+  O << "\n";
+}