Implemented constant pointer casts (like casting function pointer to void* as a constant global initializer)

dmd/expression.h

@@ -1003,6 +1003,9 @@ struct CastExp : UnaExp
 
     // For operator overloading
     Identifier *opId();
+
+    // LLVMDC
+    virtual llvm::Constant *toConstElem(IRState *irs);
 };
 
 

gen/toir.cpp

@@ -819,6 +819,22 @@ DValue* CastExp::toElem(IRState* p)
 
 //////////////////////////////////////////////////////////////////////////////////////////
 
+LLConstant* CastExp::toConstElem(IRState* p)
+{
+    Logger::print("CastExp::toConstElem: %s | %s\n", toChars(), type->toChars());
+    LOG_SCOPE;
+
+    LLConstant* c = e1->toConstElem(p);
+    assert(isaPointer(c->getType()));
+
+    const LLType* lltype = DtoType(type);
+    assert(isaPointer(lltype));
+
+    return llvm::ConstantExpr::getBitCast(c, lltype);
+}
+
+//////////////////////////////////////////////////////////////////////////////////////////
+
 DValue* SymOffExp::toElem(IRState* p)
 {
     Logger::print("SymOffExp::toElem: %s | %s\n", toChars(), type->toChars());

tests/mini/const1.d

@@ -0,0 +1,15 @@
+module mini.const1;
+
+void* g = cast(void*)&foobar;
+
+int foobar()
+{
+    return 42;
+}
+
+void main()
+{
+    auto fn = cast(int function())g;
+    int i = fn();
+    assert(i == 42);
+}