Re: some question about output section

[loody <miloody at gmail dot com>]

hi:
2011/4/28 Alan Modra <amodra@gmail.com>:
> On Wed, Apr 27, 2011 at 11:29:13PM +0800, loody wrote:
>> Dear all:
>> I have some questions as below:
>> 1. Is it possible to put whole .text of a static library to one output section?
>> 2. Is it possible to put whole sections of a static library to one
>> output section?
>> 3. is it possible for some file B to get address of some function in
>> A, while linking?
>> 4. usually the address of a static lib is not determined until link
>> stage. Is it possible we can pre-defined the address of each function
>> in a static lib?
>
> Yes, yes, yes and yes. ?As to how you can do this, see ld info doc
> node "Input Section Basics" for the answer to (1) and (2). ?For (3)
> and (4) you're going to need to compile with -ffunction-sections then
> write scripts to put the functions where you want them. ?An
> alternative to (4) is to build a jump table at a fixed address then
> define the function entry points on the jump table entries.
>
after studying the ld info, I make a link script as below:
OUTPUT_ARCH(mips)
ENTRY(entry)
SECTIONS
{
  .begin 0xbfb00000 :
  {
        *(.begin)
        . = ALIGN(8);
        _end_begin = ABSOLUTE(.);
  }
  .onlyText 0x80000000 : AT(_end_begin)
  {
     lib1.a ( *.text )
  }
  .wholelib 0x81000000 :
  {
     lib2.a (*)
  }
  .text : { *(EXCLUDE_FILE (*.a ) .text)}
  .data : { *(EXCLUDE_FILE (*.a ) .data) }
}

and I link the files by following command.
mipsel-linux-gnu-ld -T ./link.xn -o TEST_LINK.elf -Map TEST_LINK.map
--oformat elf32-tradlittlemips lib1.a lib2.a  main.o ut.o

But I cannot see the section I used to link lib1.a and lib2.a
ELF Header:
  Magic:   7f 45 4c 46 01 01 01 00 00 00 00 00 00 00 00 00
  Class:                             ELF32
  Data:                              2's complement, little endian
  Version:                           1 (current)
  OS/ABI:                            UNIX - System V
  ABI Version:                       0
  Type:                              EXEC (Executable file)
  Machine:                           MIPS R3000
  Version:                           0x1
  Entry point address:               0xbfb00000
  Start of program headers:          52 (bytes into file)
  Start of section headers:          2936 (bytes into file)
  Flags:                             0x70001001, noreorder, o32, mips32r2
  Size of this header:               52 (bytes)
  Size of program headers:           32 (bytes)
  Number of program headers:         1
  Size of section headers:           40 (bytes)
  Number of section headers:         20
  Section header string table index: 17

Section Headers:
  [Nr] Name              Type            Addr     Off    Size   ES Flg Lk Inf Al
  [ 0]                   NULL            00000000 000000 000000 00      0   0  0
  [ 1] .begin            PROGBITS        bfb00000 000054 000058 00  AX  0   0  4
  [ 2] .text             PROGBITS        bfb00058 0000ac 0002bc 00  AX  0   0  4
  [ 3] .rodata.str1.4    PROGBITS        bfb00314 000368 000014 01 AMS  0   0  4
  [ 4] .data             PROGBITS        bfb00328 00037c 000014 00  WA  0   0  4
  [ 5] .bss              NOBITS          bfb0033c 000390 000004 00  WA  0   0  4
  [ 6] .reginfo          MIPS_REGINFO    00000000 000390 000018 18      0   0  4
  [ 7] .pdr              PROGBITS        00000000 0003a8 0000a0 00      0   0  4
  [ 8] .mdebug.abi32     PROGBITS        00000000 000448 000000 00      0   0  1
  [ 9] .debug_abbrev     MIPS_DWARF      00000000 000448 0000fa 00      0   0  1
  [10] .debug_info       MIPS_DWARF      00000000 000542 0001b8 00      0   0  1
  [11] .debug_line       MIPS_DWARF      00000000 0006fa 0000bf 00      0   0  1
  [12] .debug_frame      MIPS_DWARF      00000000 0007bc 000080 00      0   0  4
  [13] .debug_pubnames   MIPS_DWARF      00000000 00083c 000083 00      0   0  1
  [14] .debug_aranges    MIPS_DWARF      00000000 0008bf 000048 00      0   0  1
  [15] .debug_str        MIPS_DWARF      00000000 000907 000154 01  MS  0   0  1
  [16] .comment          PROGBITS        00000000 000a5b 000056 00      0   0  1
  [17] .shstrtab         STRTAB          00000000 000ab1 0000c4 00      0   0  1
  [18] .symtab           SYMTAB          00000000 000e98 0001e0 10     19  24  4
  [19] .strtab           STRTAB          00000000 001078 00007a 00      0   0  1


Did I miss anything?

-- 
Regards,
miloody