undefined reference to `_D15TypeInfo_Struct6__vtblZ'

[Mike]

Thanks for all the help lately.  I'm sorry to be flooding this 
list with so many questions, but I'm making good progress, and 
still running into some things I don't quite understand.

I'm getting the following linker error as soon as I add a struct 
to my code.

undefined reference to `_D15TypeInfo_Struct6__vtblZ'

I'm guessing this is because GDC is not generating the vtbl for 
my TypeInfo_Struct class.

Is this because I'm missing something in my runtime 
implementation, or could this be a code generation bug?

I ran objdump on my object file, and this symbmol did not appear.

I'm using GDC 4.8 arm-none-eabi:

(compile) arm-none-eabi-gdc -mthumb -mcpu=cortex-m4 
-fno-emit-moduleinfo -ffunction-sections -fdata-sections -c   
start.d -o start.o

(link) arm-none-eabi-ld -T link.ld start.o -o start.elf


I've reduce my code quite a bit to the following, just to make 
the problem reproducible:

*********
start.d
*********
alias void function() ISR;
extern(C) immutable ISR[1] ISRVectorTable =
[
     &OnReset
];

void OnReset()
{
   while(true)
   { }
}

**********
object.d
**********
module object;

alias uint               size_t;
alias immutable(char)[]  string;

class Object
{}

class TypeInfo
{}

class TypeInfo_Struct : TypeInfo
{
     string name;
     void[] m_init;      // initializer; init.ptr == null if 0 
initialize

     @safe pure nothrow
     {
	size_t   function(in void*)           xtoHash;
	bool     function(in void*, in void*) xopEquals;
	int      function(in void*, in void*) xopCmp;
	char[]   function(in void*)           xtoString;

	enum StructFlags : uint
	{
	    hasPointers = 0x1,
	}
	StructFlags m_flags;
     }
     void function(void*)                    xdtor;
     void function(void*)                    xpostblit;

     uint m_align;
     immutable(void)* m_RTInfo;                // data for precise 
GC
}

***************
Linker Script
***************
MEMORY
{
   CCRAM    (rxw) : ORIGIN = 0x10000000, LENGTH =   64k
   SRAM     (rxw) : ORIGIN = 0x20000000, LENGTH =  128k
   FLASH    (rx)  : ORIGIN = 0x08000000, LENGTH = 1024k
}

_stackStart = ORIGIN(CCRAM) + LENGTH(CCRAM);

SECTIONS
{
     /* Don't need exception stuff right now */
     /DISCARD/ :
     {
	*(.ARM.extab*)
	*(.ARM.exidx*)
     }

     .text :
     {
	LONG(_stackStart);            /* Initial stack pointer */
	KEEP(*(*.ISRVectorTable))     /* Interrupt vector table */
	
	. = ALIGN(4);
	/* the code */
	*(.text)
	*(.text*)
	
	/* for "hello\r\n" string constant */
	. = ALIGN(4);
	*(.rodata)
	*(.rodata*)

	. = ALIGN(4);
	dataRomStart = .;
     } >FLASH

     .data : AT (dataRomStart)
     {
	. = ALIGN(4);
	dataRamStart = .;
	
	. = ALIGN(4);
	*(.data)
	*(.data*)

	. = ALIGN(4);
	dataRamEnd = .;
     } >SRAM

     .bss :
     {
	. = ALIGN(4);
         bssStart = .;

         *(.bss)
         *(.bss*)

	. = ALIGN(4);
	bssEnd = .;
     } >SRAM
}