llvm/test/MC/X86/align-branch-enhanced-relaxation.s

   1   # RUN: llvm-mc -mcpu=skylake -filetype=obj -triple x86_64-pc-linux-gnu %s -x86-pad-max-prefix-size=1 --x86-align-branch-boundary=32 --x86-align-branch=jmp+indirect | llvm-objdump -d - | FileCheck %s
   2   # RUN: llvm-mc -mcpu=skylake -filetype=obj -triple x86_64-pc-linux-gnu %s --mc-relax-all | llvm-objdump -d - | FileCheck --check-prefixes=RELAX-ALL %s
   3
   4   # Exercise cases where we are allowed to increase the length of unrelaxable
   5   # instructions (by adding prefixes) for alignment purposes.
   6
   7   # The first test checks instructions 'int3', 'push %rbp', which will be padded
   8   # later are unrelaxable (their encoding size is still 1 byte when
   9   # --mc-relax-all is passed).
  10   .text
  11   .globl labeled_unrelaxable_test
  12 labeled_unrelaxable_test:
  13 # RELAX-ALL:       0: cc                               int3
  14 # RELAX-ALL:       1: 54                               pushq    %rsp
  15   int3
  16   push %rsp
  17
  18   # The second test is a basic test, we just check the jmp is aligned by prefix
  19   # padding the previous instructions.
  20   .text
  21   .globl labeled_basic_test
  22 labeled_basic_test:
  23   .p2align 5
  24   .rept 28
  25   int3
  26   .endr
  27 # CHECK:      3c: 2e cc                            int3
  28 # CHECK:      3e: 2e 54                            pushq    %rsp
  29 # CHECK:      40: eb 00                            jmp
  30   int3
  31   push %rsp
  32   jmp foo
  33 foo:
  34   ret
  35
  36    # The third test check the correctness cornercase - can't add prefixes on a
  37    # prefix or a instruction following by a prefix.
  38   .globl labeled_prefix_test
  39 labeled_prefix_test:
  40   .p2align 5
  41   .rept 28
  42   int3
  43   .endr
  44 # CHECK:      7c: 2e cc                            int3
  45   int3
  46 # CHECK:      7e: 3e cc                            int3
  47   DS
  48   int3
  49 # CHECK:      80: eb 00                            jmp
  50   jmp bar
  51 bar:
  52   ret