bolt/test/X86/split-func-jump-table-unknown.s

   1 # This reproduces a bug with converting an unknown control flow jump table with
   2 # entries pointing to code in function and its cold fragment.
   3
   4 # REQUIRES: system-linux
   5
   6 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s -o %t.o
   7 # RUN: llvm-strip --strip-unneeded %t.o
   8 # RUN: %clang %cflags %t.o -o %t.exe -Wl,-q
   9 # RUN: llvm-bolt %t.exe -o %t.out --lite=0 -v=1 --strict=1 -print-cfg \
  10 # RUN:   -print-only=main 2>&1 | FileCheck %s
  11
  12 # CHECK: BOLT-INFO: marking main.cold.1 as a fragment of main
  13 # CHECK: Binary Function "main" after building cfg
  14 # CHECK: Unknown CF  : true
  15 # CHECK: jmpq    *%r8 # UNKNOWN CONTROL FLOW
  16 # CHECK: PIC Jump table JUMP_TABLE for function main
  17 # CHECK-NEXT: 0x0000 : .Ltmp0
  18 # CHECK-NEXT: 0x0004 : .Ltmp1
  19 # CHECK-NEXT: 0x0008 : __ENTRY_main.cold.1
  20 # CHECK-NEXT: 0x000c : .Ltmp1
  21   .text
  22   .globl main
  23   .type main, %function
  24   .p2align 2
  25 main:
  26 LBB0:
  27   leaq JUMP_TABLE(%rip), %r8
  28   andl $0xf, %ecx
  29   cmpb $0x4, %cl
  30   # exit through abort in main.cold.1, registers cold fragment the regular way
  31   ja main.cold.1
  32
  33 # jump table dispatch, jumping to label indexed by val in %ecx
  34 LBB1:
  35   movzbl %cl, %ecx
  36   movslq (%r8,%rcx,4), %rax
  37   addq %rax, %r8
  38   jmpq *%r8
  39
  40 LBB2:
  41   xorq %rax, %rax
  42 LBB3:
  43   addq $0x8, %rsp
  44   ret
  45 .size main, .-main
  46
  47   .globl main.cold.1
  48   .type main.cold.1, %function
  49   .p2align 2
  50 main.cold.1:
  51   # load bearing nop: pad LBB4 so that it can't be treated
  52   # as __builtin_unreachable by analyzeJumpTable
  53   nop
  54 LBB4:
  55   callq abort
  56 .size main.cold.1, .-main.cold.1
  57
  58   .rodata
  59 # jmp table, entries must be R_X86_64_PC32 relocs
  60   .globl JUMP_TABLE
  61 JUMP_TABLE:
  62   .long LBB2-JUMP_TABLE
  63   .long LBB3-JUMP_TABLE
  64   .long LBB4-JUMP_TABLE
  65   .long LBB3-JUMP_TABLE