malloc always returns null

[Ted Phares <tphares@xxxxxxxx>]

Hi,

I'm attempting to configure the gcc 4.0.3 tool chain to compile c++ 
source on an ARM 9 (ARM926-ejs) target.  At this point, everything seems 
to be working except malloc:  It always returns the null pointer.

I'm wondering if I've correctly configured my .ld script indicate the 
location and size of the heap.  It was put together with a bit of 
guesswork & patching together examples for other targets, since it's not 
clear to me what symbols malloc() relies upon for locating the heap (is 
this documented somewhere?).

Below are the command lines i'm using for compile/assemble/link & the ld 
script.  Do they look substantially complete?

Thanks,

-ted



Command lines:
================================================================

gcc.exe -c -gdwarf-2 -MD -O0 -mapcs-frame -trigraphs -mcpu=arm926ej-s -w 
-Wall  -fsigned-char  -xc++  -mlittle-endian  -marm  -mthumb-interwork 
-mtune=arm926ej-s -mlong-calls -o .\objects\mySourceFile.o mySourceFile.cpp
as.exe -mcpu=arm9e -gdwarf2  -EL  -mthumb-interwork  .\objects\startup.o 
.\source\startup.s
ld.exe  -T.\Settings\my_ld_script.ld --cref -t -static -lstdc++ -lm -lc 
-lgcc -nostartfiles -Map=my_program.map   -o .\objects\my_program.elf


ld script:
================================================================

MEMORY
{
  INTRAM(rwx) : ORIGIN = 0x00000004, LENGTH = 0x1FFFC /* this isn't used */
  SDRAM(rwx)  : ORIGIN = 0x80000000, LENGTH = 0x00800000 /* this is the 
memory i'm using */
}

SECTIONS
{
  .text :
  {
    __code_start__ = .;

    objects\startup.o (.text)         /* Startup code */
    objects\*.o       (.text)

    . = ALIGN(4);
    __code_end__ = .;

    *(.gnu.linkonce.t.*)
  	*(.glue_7)
  	*(.glue_7t)
  	*(.gcc_except_table)
  	*(.gnu.linkonce.r.*)

  } >SDRAM

  . = ALIGN(4);

  /* .rodata section which is used for read-only data (constants) */
  .rodata . :
  {
    *(.rodata)
  } >SDRAM

	.ctors :
	{
		PROVIDE(__ctors_start__ = .);
		KEEP(*(SORT(.ctors.*)))
		KEEP(*(.ctors))
		PROVIDE(__ctors_end__ = .);
	} >SDRAM

	.dtors :
	{
		PROVIDE(__dtors_start__ = .);
		KEEP(*(SORT(.dtors.*)))
		KEEP(*(.dtors))
		PROVIDE(__dtors_end__ = .);
	} >SDRAM

  _etext = . ;
  PROVIDE (etext = .);

  .data :
  {
    /* used for initialized data */
    __data_start__ = . ;
    PROVIDE (__data_start__ = .) ;
    *(.data)
   	*(.data.*)
	  *(.gnu.linkonce.d*)

    SORT(CONSTRUCTORS)
    __data_end__ = . ;
    PROVIDE (__data_end__ = .) ;
  } >SDRAM
  . = ALIGN(4);

  _edata = . ;
  PROVIDE (edata = .);

  .bss :
  {
    /* used for uninitialized data */

    __bss_start = . ;
    __bss_start__ = . ;
    *(.bss)
    *(.gnu.linkonce.b*)
    . = ALIGN(4);
    __bss_end__ = . ;

  } >SDRAM

  .bss2 :
  {
    /* used for uninitialized data */

    __bss2_start = . ;
    __bss2_start__ = . ;
    *(COMMON)
    . = ALIGN(4);
    __bss2_end__ = . ;

  } >SDRAM

  .stack ALIGN(256) :
  {
    . += 0x00100000;
    PROVIDE (_stack = .);
  } > SDRAM

  .heap :
  {
   PROVIDE (end = .);PROVIDE (__end__ = .);PROVIDE (_end = .);
   *(.heap)
   PROVIDE (heap_limit = . );
  } >SDRAM

  .comment       0 : { *(.comment) }
  /* DWARF debug sections.
     Symbols in the DWARF debugging sections are relative to the beginning
     of the section so we begin them at 0.  */
  /* DWARF 1 */
  .debug          0 : { *(.debug) }
  .line           0 : { *(.line) }
  /* GNU DWARF 1 extensions */
  .debug_srcinfo  0 : { *(.debug_srcinfo) }
  .debug_sfnames  0 : { *(.debug_sfnames) }
  /* DWARF 1.1 and DWARF 2 */
  .debug_aranges  0 : { *(.debug_aranges) }
  .debug_pubnames 0 : { *(.debug_pubnames) }
  /* DWARF 2 */
  .debug_info     0 : { *(.debug_info .gnu.linkonce.wi.*) }
  .debug_abbrev   0 : { *(.debug_abbrev) }
  .debug_line     0 : { *(.debug_line) }
  .debug_frame    0 : { *(.debug_frame) }
  .debug_str      0 : { *(.debug_str) }
  .debug_loc      0 : { *(.debug_loc) }
  .debug_macinfo  0 : { *(.debug_macinfo) }
}