[Bug ld/21038] New: Incorrect unwind info for BND PLT

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=21038

            Bug ID: 21038
           Summary: Incorrect unwind info for BND PLT
           Product: binutils
           Version: 2.29 (HEAD)
            Status: NEW
          Severity: normal
          Priority: P2
         Component: ld
          Assignee: unassigned at sourceware dot org
          Reporter: hjl.tools at gmail dot com
  Target Milestone: ---
            Target: x86-64

address@hidden mpx-6]$ cat y.S 
        .text
        .globl foo
        .type foo, @function
foo:
        .cfi_startproc
        call    address@hidden
        .cfi_endproc
address@hidden mpx-6]$ make LD=ld
gcc -B./    -c -o y.o y.S
ld -z bndplt -shared -o y.so y.o
./objdump -Wf -dw y.so

y.so:     file format elf64-x86-64

Contents of the .eh_frame section:

00000000 0000000000000014 00000000 CIE
  Version:               1
  Augmentation:          "zR"
  Code alignment factor: 1
  Data alignment factor: -8
  Return address column: 16
  Augmentation data:     1b

  DW_CFA_def_cfa: r7 (rsp) ofs 8
  DW_CFA_offset: r16 (rip) at cfa-8
  DW_CFA_nop
  DW_CFA_nop

00000018 0000000000000014 0000001c FDE cie=00000000
pc=0000000000000248..000000000000024d
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop

00000030 0000000000000024 00000034 FDE cie=00000000
pc=0000000000000220..0000000000000240
  DW_CFA_def_cfa_offset: 16
  DW_CFA_advance_loc: 6 to 0000000000000226
  DW_CFA_def_cfa_offset: 24
  DW_CFA_advance_loc: 10 to 0000000000000230
  DW_CFA_def_cfa_expression (DW_OP_breg7 (rsp): 8; DW_OP_breg16 (rip): 0;
DW_OP_lit15; DW_OP_and; DW_OP_lit11; DW_OP_ge; DW_OP_lit3; DW_OP_shl;
DW_OP_plus)
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop
  DW_CFA_nop


Disassembly of section .plt:

0000000000000220 <.plt>:
 220:   ff 35 e2 0d 20 00       pushq  0x200de2(%rip)        # 201008
<_GLOBAL_OFFSET_TABLE_+0x8>
 226:   f2 ff 25 e3 0d 20 00    bnd jmpq *0x200de3(%rip)        # 201010
<_GLOBAL_OFFSET_TABLE_+0x10>
 22d:   0f 1f 00                nopl   (%rax)
 230:   68 00 00 00 00          pushq  $0x0
 235:   f2 e9 e5 ff ff ff       bnd jmpq 220 <.plt>
 23b:   0f 1f 44 00 00          nopl   0x0(%rax,%rax,1)

Disassembly of section .plt.bnd:

0000000000000240 <address@hidden>:
 240:   f2 ff 25 d1 0d 20 00    bnd jmpq *0x200dd1(%rip)        # 201018 <func>
 247:   90                      nop

Disassembly of section .text:

0000000000000248 <foo>:
 248:   e8 f3 ff ff ff          callq  240 <address@hidden>
address@hidden mpx-6]$ 

Since the BND PLT has

 230:   68 00 00 00 00          pushq  $0x0
 235:   f2 e9 e5 ff ff ff       bnd jmpq 220 <.plt>
 23b:   0f 1f 44 00 00          nopl   0x0(%rax,%rax,1)

instead of

 230:   ff 25 e2 0d 20 00       jmpq   *0x200de2(%rip)        # 201018 <func>
 236:   68 00 00 00 00          pushq  $0x0
 23b:   e9 e0 ff ff ff          jmpq   220 <.plt>

Its unwind info should be

  DW_CFA_def_cfa_expression (DW_OP_breg7 (rsp): 8; DW_OP_breg16 (rip): 0;
DW_OP_lit15; DW_OP_and; DW_OP_lit5; DW_OP_ge; DW_OP_lit3; DW_OP_shl;
DW_OP_plus)

-- 
You are receiving this mail because:
You are on the CC list for the bug.