1# RUN: llvm-mc -mcpu=skylake -filetype=obj -triple x86_64-pc-linux-gnu %s -x86-pad-max-prefix-size=5 | llvm-objdump -d --section=.text - | FileCheck %s 2 3# This test file highlights the interactions between prefix padding and 4# relaxation padding. 5 6 .file "test.c" 7 .text 8 .section .text 9 # We can both relax and prefix for padding purposes, but the moment, we 10 # can't prefix without first having relaxed. 11 # CHECK: .text 12 # CHECK: 0: eb 1f jmp 13 # CHECK: 2: eb 1d jmp 14 # CHECK: 4: eb 1b jmp 15 # CHECK: 6: eb 19 jmp 16 # CHECK: 8: eb 17 jmp 17 # CHECK: a: 2e 2e 2e 2e 2e e9 0d 00 00 00 jmp 18 # CHECK: 14: 2e 2e 2e 2e 2e e9 03 00 00 00 jmp 19 # CHECK: 1e: 66 90 nop 20 # CHECK: 20: cc int3 21 .p2align 4 22 jmp foo 23 jmp foo 24 jmp foo 25 jmp foo 26 jmp foo 27 jmp foo 28 jmp foo 29 .p2align 5 30 int3 31foo: 32 ret 33 34 # Canonical toy loop to show benefit - we can align the loop header with 35 # fewer nops by relaxing the branch, even though we don't need to 36 # CHECK: <loop_preheader>: 37 # CHECK: 45: 48 85 c0 testq %rax, %rax 38 # CHECK: 48: 2e 2e 2e 2e 0f 8e 1e 00 00 00 jle 0x70 <loop_exit> 39 # CHECK: 52: 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 nopw %cs:(%rax,%rax) 40 # CHECK: <loop_header>: 41 # CHECK: 60: 48 83 e8 01 subq $1, %rax 42 # CHECK: 64: 48 85 c0 testq %rax, %rax 43 # CHECK: 67: 7e 07 jle 0x70 <loop_exit> 44 # CHECK: 69: 2e 2e e9 f0 ff ff ff jmp 45 # CHECK: <loop_exit>: 46 # CHECK: 70: c3 retq 47 .p2align 5 48 .skip 5 49loop_preheader: 50 testq %rax, %rax 51 jle loop_exit 52 .p2align 5 53loop_header: 54 subq $1, %rax 55 testq %rax, %rax 56 jle loop_exit 57 jmp loop_header 58 .p2align 4 59loop_exit: 60 ret 61 62 # Correctness cornercase - can't prefix pad jmp without having relaxed it 63 # first as doing so would make the relative offset too large 64 # CHECK: fd: cc int3 65 # CHECK: fe: eb 80 jmp 0x80 <loop_exit+0x10> 66 # CHECK: 100: cc int3 67.p2align 5 68.L1: 69.rept 126 70 int3 71.endr 72 jmp .L1 73.rept 30 74 int3 75.endr 76.p2align 5 77