[Sdcc-user] PIC18F aliasing CAN SFRs gives multiple absolute sections using same address error

[Jānis Š. <jan...@gm...>]

Hello,

I'm trying to define an alias to CAN buffers of a PIC18F25K80 chips
somewhat like:

typedef struct
{
	union
	{
		struct
		{
			unsigned CON_FLTHIT : 5;
			unsigned CON_RTRRO  : 1;
			unsigned CON_RXM1   : 1;
			unsigned CON_RXFUL  : 1;
		};
		uint8_t CON;
	};
	uint8_t SIDH;
	uint8_t SIDL;
	uint8_t EIDH;
	uint8_t EIDL;
	uint8_t DLC;
	uint8_t D[8];
} can_buffer_t;

volatile __at(0xF60) can_buffer_t RXB0;
volatile __at(0xF30) can_buffer_t RXB1;
volatile __at(0xE80) can_buffer_t B0;
volatile __at(0xE90) can_buffer_t B1;
volatile __at(0xEA0) can_buffer_t B2;
volatile __at(0xEB0) can_buffer_t B3;
volatile __at(0xEC0) can_buffer_t B4;
volatile __at(0xED0) can_buffer_t B5;

but this ends up giving me errors:
error: More absolute sections use same address: 0xe80 -- "ustat_can_00/_B0", "ustat_pic18f25k80_00/_B0CONbits"
error: More absolute sections use same address: 0xf60 -- "ustat_can_07/_RXB0", "ustat_pic18f25k80_01/_RXB0CONbits"

however if I make the variables extern, I get:
error: Missing definition for symbol "_RXB0", required by "can_left.o".
error: Missing definition for symbol "_RXB1", required by "can_left.o".
error: Missing definition for symbol "_B5", required by "can_left.o".
error: Missing definition for symbol "_B4", required by "can_left.o".
error: Missing definition for symbol "_B3", required by "can_left.o".
error: Missing definition for symbol "_B2", required by "can_left.o".
error: Missing definition for symbol "_B1", required by "can_left.o".
error: Missing definition for symbol "_B0", required by "can_left.o".

I get that the variables are assigned ustat section which collides with
the section emitted by pic18f15k80.c, but it does have multiple
variables with same address in itself.

Am I doing something wrong?
Can I have the code to emit only symbols but not a memory section (if
it makes sense)?

With thanks,
Jānis