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
}

Am Mon, 23 Dec 2013 12:03:09 +0000
schrieb "Mike" <none@none.com>:

> 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'
> 

It looks like you didn't compile object.d? The vtblZ symbols are only generated when you compile a .d file and then you have to link in the resulting object file, importing alone is not enough.

So something like
arm-eabi-gdc object.d -o object.o
link object.o start.o -o start

On Monday, 23 December 2013 at 12:57:33 UTC, Johannes Pfau wrote:
> Am Mon, 23 Dec 2013 12:03:09 +0000
> schrieb "Mike" <none@none.com>:
>
>> 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'
>> 
>
> It looks like you didn't compile object.d? The vtblZ symbols are only
> generated when you compile a .d file and then you have to link in the
> resulting object file, importing alone is not enough.
>
> So something like
> arm-eabi-gdc object.d -o object.o
> link object.o start.o -o start

Thanks johannes.  I already tried just as you suggested, but when I tried it, I ended up with multiple definitions as shown below.  This is why I assumed it was compiled automatically

start.o:(.rodata._D6Object6__initZ+0x0): multiple definition of `_D6Object6__initZ'
object.o:(.rodata._D6Object6__initZ+0x0): first defined here
start.o:(.rodata._D6Object6__vtblZ+0x0): multiple definition of `_D6Object6__vtblZ'
object.o:(.rodata._D6Object6__vtblZ+0x0): first defined here
start.o:(.data._D6Object7__ClassZ+0x0): multiple definition of `_D6Object7__ClassZ'
object.o:(.data._D6Object7__ClassZ+0x0): first defined here
start.o:(.rodata._D14TypeInfo_Class6__vtblZ+0x0): multiple definition of `_D14TypeInfo_Class6__vtblZ'
object.o:(.rodata._D14TypeInfo_Class6__vtblZ+0x0): first defined here


So I'm quite confused.  Do I need and object.di file instead? Is there something to naming "object_.d" (trailing underscore) instead of "object.d"?

On Monday, 23 December 2013 at 13:19:21 UTC, Mike wrote:
> On Monday, 23 December 2013 at 12:57:33 UTC, Johannes Pfau wrote:
>> Am Mon, 23 Dec 2013 12:03:09 +0000
>> schrieb "Mike" <none@none.com>:
>>
>>> 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'
>>> 
>>
>> It looks like you didn't compile object.d? The vtblZ symbols are only
>> generated when you compile a .d file and then you have to link in the
>> resulting object file, importing alone is not enough.
>>
>> So something like
>> arm-eabi-gdc object.d -o object.o
>> link object.o start.o -o start
>
> Thanks johannes.  I already tried just as you suggested, but when I tried it, I ended up with multiple definitions as shown below.  This is why I assumed it was compiled automatically
>
> start.o:(.rodata._D6Object6__initZ+0x0): multiple definition of `_D6Object6__initZ'
> object.o:(.rodata._D6Object6__initZ+0x0): first defined here
> start.o:(.rodata._D6Object6__vtblZ+0x0): multiple definition of `_D6Object6__vtblZ'
> object.o:(.rodata._D6Object6__vtblZ+0x0): first defined here
> start.o:(.data._D6Object7__ClassZ+0x0): multiple definition of `_D6Object7__ClassZ'
> object.o:(.data._D6Object7__ClassZ+0x0): first defined here
> start.o:(.rodata._D14TypeInfo_Class6__vtblZ+0x0): multiple definition of `_D14TypeInfo_Class6__vtblZ'
> object.o:(.rodata._D14TypeInfo_Class6__vtblZ+0x0): first defined here
>
>
> So I'm quite confused.  Do I need and object.di file instead? Is there something to naming "object_.d" (trailing underscore) instead of "object.d"?

Cancel that.  I had a makefile typo.  My mistake.  You are correct.