RE: VMA section overlap warnings for overlays

["David Stubbs" <stubbs at IceraSemi dot com>]

> > Am I doing something wrong or unusual in my linker script, or
> does it
> > look like there's a problem in the linker?
> 
> Your script is fine.  I'm looking at reverting Jan's patch.

On a related note, I've noticed that a slightly 'enhanced' version of
the linker script ends up with incorrect LMAs being used. Here's the
script:

---
UTPUT_FORMAT("elf32-i386")
OUTPUT_ARCH(i386)

ENTRY(_start)

PHDRS
{
  mem PT_LOAD;
  info PT_LOAD;
  imem PT_LOAD;
}

SECTIONS
{
  .text 0x1000:
  {
    *(.text)
  } :mem

  .overlays 0x9000:
  {
    LONG (LOADADDR (.overlay1))
    LONG (LOADADDR (.overlay2))
    LONG (LOADADDR (.overlay3))
  } :info

  .imem 0x2000 : AT (LOADADDR (.text) + SIZEOF (.text))
  {
    *(.imem)
  } :imem

  .overlay1 ALIGN (ADDR (.imem) + SIZEOF (.imem), 8K) 
    : AT (LOADADDR (.imem) + SIZEOF (.imem))
  {
    *(.overlay.1)
  } :imem
       
  .overlay2 ALIGN (ADDR (.imem) + SIZEOF (.imem), 8K)
    : AT (LOADADDR (.overlay1) + SIZEOF (.overlay1))
  {
    *(.overlay.2)
  } :imem

  .overlay3 ALIGN (ADDR (.imem) + SIZEOF (.imem), 8k)
    : AT (LOADADDR (.overlay2) + SIZEOF (.overlay2))
  {
    *(.overlay.3)
  } :imem
}
---

The .overlays section reports the load addresses as:

---
Hex dump of section '.overlays':
  0x00009000          00001004 00001003 00001002 ............
---

Whereas the section headers report:

---
Idx Name          Size      VMA       LMA       File off  Algn
  1 .overlay1     00000001  00004000  00003001  00005000  2**0
  4 .overlay2     00000001  00004000  00003002  00005001  2**0
  5 .overlay3     00000001  00004000  00003003  00005002  2**0
---

So the LMAs in the .overlays section do not match the LMAs in the
section headers. And for completeness, the program headers looks like:

---
Program Headers:
  Type           Offset   VirtAddr   PhysAddr   FileSiz MemSiz  Flg
Align
  LOAD           0x001000 0x00001000 0x00001000 0x00001 0x00001 R E
0x1000
  LOAD           0x002000 0x00009000 0x00009000 0x0000c 0x0000c RW
0x1000
  LOAD           0x003000 0x00002000 0x00001001 0x02003 0x02003 R E
0x1000

 Section to Segment mapping:
  Segment Sections...
   00     .text 
   01     .overlays 
   02     .overlay1 .imem .overlay2 .overlay3
---

I think it's the contents of the .overlays section that is actually
incorrect in this case. 

I don't think reverting that patch alone fixes it though. In fact, from
a very quick test I get this error:

---
/home/stubbs/local_disc/work/gnu_live_sources/binutils/build/ld/ld-new:
test.exe: section `.overlay1' can't be allocated in segment 2
LOAD: .imem .overlay1 .overlay2 .overlay3
---

Which definitely doesn't look correct to me. There must be some other
associated change that I've not yet found...

I was planning on taking another look into this, but would obviously
appreciate any help you can provide!

Thanks again,
Dave.