From 625f28814d4e331d4d989c090d6eebc2a2cc916d Mon Sep 17 00:00:00 2001
From: Christian Kamm <kamm@incasoftware.de>
Date: Tue, 15 Jul 2008 14:53:16 +0200
Subject: [PATCH] [svn r393] Started implementation for DtoNullValue.

---
 gen/llvmhelpers.cpp | 46 +++++++++++++++++++++++++++++++++++++++++++--
 gen/llvmhelpers.h   |  3 +++
 2 files changed, 47 insertions(+), 2 deletions(-)

diff --git a/gen/llvmhelpers.cpp b/gen/llvmhelpers.cpp
index 4e0337d1..316b683c 100644
--- a/gen/llvmhelpers.cpp
+++ b/gen/llvmhelpers.cpp
@@ -628,6 +628,49 @@ void DtoAssign(DValue* lhs, DValue* rhs)
     }
 }
 
+/****************************************************************************************/
+/*////////////////////////////////////////////////////////////////////////////////////////
+//      NULL VALUE HELPER
+////////////////////////////////////////////////////////////////////////////////////////*/
+
+DValue* DtoNullValue(Type* type)
+{
+    Type* basetype = type->toBasetype();
+    TY basety = basetype->ty;
+    const LLType* lltype = DtoType(basetype);
+
+    // complex, needs to be first since complex are also floating
+    if (basetype->iscomplex())
+    {
+        const LLType* basefp = DtoComplexBaseType(basetype);
+        return new DComplexValue(type, LLConstant::getNullValue(basefp), LLConstant::getNullValue(basefp));
+    }
+    // integer, floating, pointer and class have no special representation
+    else if (basetype->isintegral() || basetype->isfloating() || basety == Tpointer || basety == Tclass)
+    {
+        return new DConstValue(type, LLConstant::getNullValue(lltype));
+    }
+    // dynamic array
+    else if (basety == Tarray)
+    {
+        //TODO: What types do the constants here need to have?
+        return new DSliceValue(type, NULL, NULL);
+    }
+    // delegate
+    else if (basety == Tdelegate)
+    {
+        //TODO: Is this correct?
+        return new DNullValue(type, LLConstant::getNullValue(lltype));
+    }
+
+    // unknown
+    std::cout << "unsupported: null value for " << type->toChars() << '\n';
+    assert(0);
+    return 0;
+
+}
+
+
 /****************************************************************************************/
 /*////////////////////////////////////////////////////////////////////////////////////////
 //      CASTING HELPERS
@@ -1335,8 +1378,7 @@ LLValue* DtoBoolean(DValue* dval)
     // complex
     else if (dtype->iscomplex())
     {
-        // huh?
-        return DtoComplexEquals(TOKnotequal, dval, DtoComplex(dtype, new DNullValue(Type::tint8, llvm::ConstantInt::get(LLType::Int8Ty, 0))));
+        return DtoComplexEquals(TOKnotequal, dval, DtoNullValue(dtype));
     }
     // floating point
     else if (dtype->isfloating())
diff --git a/gen/llvmhelpers.h b/gen/llvmhelpers.h
index e8244fc0..989d0bff 100644
--- a/gen/llvmhelpers.h
+++ b/gen/llvmhelpers.h
@@ -41,6 +41,9 @@ LLValue* DtoNestedVariable(VarDeclaration* vd);
 // basic operations
 void DtoAssign(DValue* lhs, DValue* rhs);
 
+// create a null dvalue
+DValue* DtoNullValue(Type* t);
+
 // casts
 DValue* DtoCastInt(DValue* val, Type* to);
 DValue* DtoCastPtr(DValue* val, Type* to);