bolt/test/runtime/X86/fix-branches-jrcxz.s

   1 # Test BOLT does not crash by trying to change the direction of a JRCXZ
   2
   3 # REQUIRES: system-linux
   4
   5 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown \
   6 # RUN:   %s -o %t.o
   7 # RUN: link_fdata %s %t.o %t.fdata
   8 # RUN: llvm-strip --strip-unneeded %t.o
   9 # RUN: %clang %cflags -no-pie %t.o -o %t.exe -Wl,-q
  10 # RUN: llvm-bolt %t.exe --relocs=1 --reorder-blocks=ext-tsp --print-finalized \
  11 # RUN:    -o %t.out --data %t.fdata | FileCheck %s
  12 # RUN: %t.out 1 2 3
  13
  14 # CHECK: BOLT-INFO
  15
  16   .text
  17   .section .text.startup,"ax",@progbits
  18   .p2align 5,,31
  19   .globl main
  20   .type main, %function
  21 main:
  22   jmp test_function
  23
  24 .globl test_function
  25 .hidden test_function
  26 .type test_function,@function
  27 .align 32
  28 test_function:
  29 # FDATA: 0 main 0 1 test_function 0 0 510
  30   xorq %rcx, %rcx
  31   andq $3, %rdi
  32   jmpq *jumptbl(,%rdi,8)
  33
  34 # Here are the 4 possible targets of the indirect branch to simulate a simple
  35 # CFG. What is important here is that BB1, the first block, conditionally
  36 # transfers control to the exit block with JRCXZ (.J1). We create a mock profile
  37 # saying that this branch is taken more often than not, causing BOLT to try to
  38 # put the exit block after it, which would require us to change the direction
  39 # of JRCXZ.
  40 .BB1:
  41   movl $0x0, %eax
  42 .J1:
  43   jrcxz .BBend
  44 # FDATA: 1 test_function #.J1# 1 test_function #.BB2# 0 10
  45 # FDATA: 1 test_function #.J1# 1 test_function #.BBend# 0 500
  46 .BB2:
  47   movl $0x2, %eax
  48   jmp .BBend
  49 .Lbb3:
  50   movl $0x3, %eax
  51   jmp .BBend
  52 .Lbb4:
  53   movl $0x4, %eax
  54 .BBend:
  55   retq
  56 .Lend1:
  57
  58   .section .rodata
  59   .globl jumptbl
  60 jumptbl:
  61   .quad .BB1
  62   .quad .BB2
  63   .quad .Lbb3
  64   .quad .Lbb4