Hello, The VAX/ELF backend lacks a platform-specific PLT disassembly helper. The result is the table is messed up in the dump. Here's an example: $ vax-linux-objdump -d -j .plt ld.so.1 ld.so.1: file format elf32-vax Disassembly of section .plt: 000005c8 <.plt>: 5c8: dd ef 7e 42 pushl 1484c <_GLOBAL_OFFSET_TABLE_+0x4> 5cc: 01 00 5ce: 17 ff 7c 42 jmp *14850 <_GLOBAL_OFFSET_TABLE_+0x8> 5d2: 01 00 5d4: fc xfc 5d5: 0f 16 ef ec remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5d9: ff ff ff 5dc: 00 halt 5dd: 00 halt 5de: 00 halt 5df: 00 halt 5e0: fc xfc 5e1: 0f 16 ef e0 remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5e5: ff ff ff 5e8: 0c 00 00 00 prober $0x0,$0x0,$0x0 5ec: fc xfc 5ed: 0f 16 ef d4 remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5f1: ff ff ff 5f4: 18 00 bgeq 5f6 <GLIBC_2.0+0x5f6> 5f6: 00 halt 5f7: 00 halt 5f8: fc xfc 5f9: 0f 16 ef c8 remque $0x16,5c8 <GLIBC_2.0+0x5c8> 5fd: ff ff ff 600: 24 00 00 00 cvtpt $0x0,$0x0,$0x0,*0xbcef160f(ap),*31060d <_end+0x2fb511> 604: fc 0f 16 ef 608: bc ff ff ff 60c: 30 00 ... The patch below implements the helper needed. There is a small issue with weak symbols which do not have the BSF_FUNCTION flag set and therefore do not match the usual logic to trigger entry mask decoding. To solve this problem, I have made use of an observation that the BSF_SYNTHETIC flag is only set for PLT symbols for the VAX target. If this ever changes in the future code will have to be adjusted accordingly. Here's a dump of the same PLT as above obtained with the patch applied: $ vax-linux-objdump -d -j .plt ld.so.1 ld.so.1: file format elf32-vax Disassembly of section .plt: 000005c8 <__libc_memalign@plt-0xc>: 5c8: dd ef 7e 42 pushl 1484c <_GLOBAL_OFFSET_TABLE_+0x4> 5cc: 01 00 5ce: 17 ff 7c 42 jmp *14850 <_GLOBAL_OFFSET_TABLE_+0x8> 5d2: 01 00 000005d4 <__libc_memalign@plt>: 5d4: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5d6: 16 ef ec ff jsb 5c8 <GLIBC_2.0+0x5c8> 5da: ff ff 5dc: 00 00 00 00 .long 0x00000000 000005e0 <malloc@plt>: 5e0: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5e2: 16 ef e0 ff jsb 5c8 <GLIBC_2.0+0x5c8> 5e6: ff ff 5e8: 0c 00 00 00 .long 0x0000000c 000005ec <calloc@plt>: 5ec: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5ee: 16 ef d4 ff jsb 5c8 <GLIBC_2.0+0x5c8> 5f2: ff ff 5f4: 18 00 00 00 .long 0x00000018 000005f8 <realloc@plt>: 5f8: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 5fa: 16 ef c8 ff jsb 5c8 <GLIBC_2.0+0x5c8> 5fe: ff ff 600: 24 00 00 00 .long 0x00000024 00000604 <free@plt>: 604: fc 0f .word 0x0ffc # Entry mask: < r11 r10 r9 r8 r7 r6 r5 r4 r3 r2 > 606: 16 ef bc ff jsb 5c8 <GLIBC_2.0+0x5c8> 60a: ff ff 60c: 30 00 00 00 .long 0x00000030 bfd/ 2009-06-04 Maciej W. Rozycki <macro@linux-mips.org> * elf32-vax.c (elf_vax_plt_sym_val): New function. (elf_backend_plt_sym_val): Define. opcodes/ 2009-06-04 Maciej W. Rozycki <macro@linux-mips.org> * vax-dis.c (is_function_entry): Return success for synthetic symbols too. (is_plt_tail): New function. (print_insn_vax): Decode PLT entry offset longword. OK to apply? Maciej binutils-2.19.1-vax-plt-sym.patch diff -up --recursive --new-file binutils-2.19.1.macro/bfd/elf32-vax.c binutils-2.19.1/bfd/elf32-vax.c --- binutils-2.19.1.macro/bfd/elf32-vax.c 2008-01-11 09:07:03.000000000 +0000 +++ binutils-2.19.1/bfd/elf32-vax.c 2009-05-15 22:46:54.000000000 +0000 @@ -47,6 +47,8 @@ static bfd_boolean elf_vax_finish_dynami Elf_Internal_Sym *); static bfd_boolean elf_vax_finish_dynamic_sections (bfd *, struct bfd_link_info *); +static bfd_vma elf_vax_plt_sym_val (bfd_vma, const asection *, + const arelent *); static bfd_boolean elf32_vax_set_private_flags (bfd *, flagword); static bfd_boolean elf32_vax_merge_private_bfd_data (bfd *, bfd *); @@ -2068,6 +2070,13 @@ elf_vax_finish_dynamic_sections (bfd *ou return TRUE; } +static bfd_vma +elf_vax_plt_sym_val (bfd_vma i, const asection *plt, + const arelent *rel ATTRIBUTE_UNUSED) +{ + return plt->vma + (i + 1) * PLT_ENTRY_SIZE; +} + #define TARGET_LITTLE_SYM bfd_elf32_vax_vec #define TARGET_LITTLE_NAME "elf32-vax" #define ELF_MACHINE_CODE EM_VAX @@ -2092,6 +2101,7 @@ elf_vax_finish_dynamic_sections (bfd *ou elf_vax_finish_dynamic_sections #define elf_backend_gc_mark_hook elf_vax_gc_mark_hook #define elf_backend_gc_sweep_hook elf_vax_gc_sweep_hook +#define elf_backend_plt_sym_val elf_vax_plt_sym_val #define bfd_elf32_bfd_merge_private_bfd_data \ elf32_vax_merge_private_bfd_data #define bfd_elf32_bfd_set_private_flags \ diff -up --recursive --new-file binutils-2.19.1.macro/opcodes/vax-dis.c binutils-2.19.1/opcodes/vax-dis.c --- binutils-2.19.1.macro/opcodes/vax-dis.c 2007-07-05 09:49:02.000000000 +0000 +++ binutils-2.19.1/opcodes/vax-dis.c 2009-05-15 23:52:10.000000000 +0000 @@ -171,21 +171,24 @@ free_entry_array (void) } } #endif -/* Check if the given address is a known function entry. Either there must - be a symbol of function type at this address, or the address must be - a forced entry point. The later helps in disassembling ROM images, because - there's no symbol table at all. Forced entry points can be given by - supplying several -M options to objdump: -M entry:0xffbb7730. */ +/* Check if the given address is a known function entry point. This is + the case if there is a symbol of the function type at this address. + We also check for synthetic symbols as these are used for PLT entries + (weak undefined symbols may not have the function type set). Finally + the address may have been forced to be treated as an entry point. The + latter helps in disassembling ROM images, because there's no symbol + table at all. Forced entry points can be given by supplying several + -M options to objdump: -M entry:0xffbb7730. */ static bfd_boolean is_function_entry (struct disassemble_info *info, bfd_vma addr) { unsigned int i; - /* Check if there's a BSF_FUNCTION symbol at our address. */ + /* Check if there's a function or PLT symbol at our address. */ if (info->symbols && info->symbols[0] - && (info->symbols[0]->flags & BSF_FUNCTION) + && (info->symbols[0]->flags & (BSF_FUNCTION | BSF_SYNTHETIC)) && addr == bfd_asymbol_value (info->symbols[0])) return TRUE; @@ -197,6 +200,22 @@ is_function_entry (struct disassemble_in return FALSE; } +/* Check if the given address is the last longword of a PLT entry. + This longword is data and depending on the value it may interfere + with disassembly of further PLT entries. We make use of the fact + PLT symbols are marked BSF_SYNTHETIC. */ +static bfd_boolean +is_plt_tail (struct disassemble_info *info, bfd_vma addr) +{ + if (info->symbols + && info->symbols[0] + && (info->symbols[0]->flags & BSF_SYNTHETIC) + && addr == bfd_asymbol_value (info->symbols[0]) + 8) + return TRUE; + + return FALSE; +} + static int print_insn_mode (const char *d, int size, @@ -412,6 +431,18 @@ print_insn_vax (bfd_vma memaddr, disasse return 2; } + /* Decode PLT entry offset longword. */ + if (is_plt_tail (info, memaddr)) + { + int offset; + + FETCH_DATA (info, buffer + 4); + offset = buffer[3] << 24 | buffer[2] << 16 | buffer[1] << 8 | buffer[0]; + (*info->fprintf_func) (info->stream, ".long 0x%08x", offset); + + return 4; + } + for (votp = &votstrs[0]; votp->name[0]; votp++) { vax_opcodeT opcode = votp->detail.code; _______________________________________________ Linux-Vax mailing list Linux-Vax@mail.pergamentum.com http://mail.pergamentum.com/mailman/listinfo/linux-vax