bolt/test/runtime/X86/shrinkwrapping-lock.s

   1 # This reproduces a bug with shrink wrapping when moving
   2 # load instructions in-between the lock prefix and another
   3 # instruction (where the lock prefix applies).
   4
   5 # REQUIRES: system-linux
   6
   7 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown \
   8 # RUN:   %s -o %t.o
   9 # RUN: link_fdata %s %t.o %t.fdata
  10 # Delete our BB symbols so BOLT doesn't mark them as entry points
  11 # RUN: llvm-strip --strip-unneeded %t.o
  12 # RUN: %clang %cflags -no-pie %t.o -o %t.exe -Wl,-q
  13
  14 # RUN: llvm-bolt %t.exe --relocs=1 --frame-opt=all --print-fop \
  15 # RUN:    --print-only=main --data %t.fdata -o %t.out | FileCheck %s
  16
  17 # RUN: %t.out 1
  18
  19 # CHECK: BOLT-INFO: Shrink wrapping moved 1 spills inserting load/stores and 0 spills inserting push/pops
  20
  21   .text
  22   .globl  main
  23   .type main, %function
  24   .p2align  4
  25 main:
  26 # FDATA: 0 [unknown] 0 1 main 0 0 510
  27   pushq %rbp
  28   movq  %rsp, %rbp
  29   pushq %rbx                  # We save rbx here, but there is an
  30                               # opportunity to move it to .LBB2
  31   subq  $0x18, %rsp
  32   cmpl  $0x2, %edi
  33 .J1:
  34   jb    .BBend
  35 # FDATA: 1 main #.J1# 1 main #.BB2# 0 10
  36 # FDATA: 1 main #.J1# 1 main #.BBend# 0 500
  37 .BB2:
  38   movq $2, %rbx               # Use rbx in a cold block. Save rbx will be moved
  39                               # just before this instruction.
  40   xorq %rax, %rax
  41   movb mystring, %al
  42   addq %rbx, %rax
  43   movb %al, mystring
  44   leaq mystring, %rdi
  45   callq puts
  46   lock add %r12,0x0(%rsp)     # Put a lock in an unrelated instruction at the
  47                               # dom. frontier where the restore will be moved to
  48                               # We should not put the restore in-between the
  49                               # lock and add! We typically avoid putting a
  50                               # restore in the last BB instruction, but since
  51                               # lock in llvm MC lib is considered a
  52                               # separate instruction, we may mistakenly
  53                               # put the restore just between these two.
  54
  55 .BBend:
  56   addq $0x18, %rsp
  57   pop %rbx                    # Restore should be moved
  58   xorq %rax, %rax
  59   leaveq
  60   retq
  61   .size main, .-main
  62
  63   .data
  64 mystring: .asciz "0 is rbx mod 10 contents in decimal\n"