Is it correct for TI ARM Clang v1.3.0 to place .init_array in a read/write section?

Hi Chester,

Let me run this by our tools group.

Hi Chester,

The example in the tiarmclang user guide that you refer to uses an example linker command file:

/****************************************************************************/
/* Example Linker Command File                                              */
/****************************************************************************/
-c                                         /* LINK USING C CONVENTIONS      */
-stack  0x8000                             /* SOFTWARE STACK SIZE           */
-heap   0x2000                             /* HEAP AREA SIZE                */
--args  0x1000

/* SPECIFY THE SYSTEM MEMORY MAP */

MEMORY
{
    P_MEM    : org = 0x00000020   len = 0x20000000  /* PROGRAM MEMORY (ROM) */
    D_MEM    : org = 0x20000020   len = 0x20000000  /* DATA MEMORY    (RAM) */
}

/* SPECIFY THE SECTIONS ALLOCATION INTO MEMORY */

SECTIONS
{
    .intvecs    : {} > 0x0             /* INTERRUPT VECTORS                 */
    .bss        : {} > D_MEM           /* GLOBAL & STATIC VARS              */
    .data       : {} > D_MEM
    .sysmem     : {} > D_MEM           /* DYNAMIC MEMORY ALLOCATION AREA    */
    .stack      : {} > D_MEM           /* SOFTWARE SYSTEM STACK             */

    .text       : {} > P_MEM           /* CODE                              */
    .cinit      : {} > P_MEM           /* INITIALIZATION TABLES             */
    .const      : {} > P_MEM           /* CONSTANT DATA                     */
    .rodata     : {} > P_MEM
    .ARM.exidx  : {} > P_MEM
    .init_array : {} > P_MEM           /* C++ CONSTRUCTOR TABLES            */
}

this is not intended to model memory on any particular device. I run that example on an internal standalone simulator. Perhaps this could be made clearer in the user guide text.

With that said, I find it strange that the linker does cinit compression on the .init_array section since it is only 8 bytes long. I will look into that.

Are you able to run a simple hello world program using a linker command file that models the memory layout of the MSP432 device?

~ Todd

Todd Snider said:

With that said, I find it strange that the linker does cinit compression on the .init_array section since it is only 8 bytes long

I agree that looks strange, and appears to be the reason why the .init_array section gets created as read/write. The compressed "load size" is 13 bytes and the un-compressed "run size" is 8 bytes, and so the compression isn't actually saving any space.

Todd Snider said:

Are you able to run a simple hello world program using a linker command file that models the memory layout of the MSP432 device?

Looking at a CCS 10.3.0.00007 it is only the following device files which contain setup information for TICLANG:

$ find ~/ti/ccs1030/ccs/ccs_base/ -name '*.xml' -print0 | xargs -0 -n100 grep -l TICLANG
/home/mr_halfword/ti/ccs1030/ccs/ccs_base/common/targetdb/devices/msp432e411y.xml
/home/mr_halfword/ti/ccs1030/ccs/ccs_base/common/targetdb/devices/msp432e401y.xml

The C++ hello world attached in the first post was created for a MSP432E401Y as that is one of the devices in CCS 10.3 which had support to TICLANG when creating a new project, and the msp432e401y.cmd copied into the project at creation placed .init_array in FLASH.

If the msp432e401y.cmd is changed to place .init_array in SRAM then the program runs.