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

   1 ## This reproduces a bug with jump table identification where jump table has
   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 --print-cfg --print-only=main \
  10 # RUN:   2>&1 | FileCheck %s
  11
  12 # CHECK-NOT: unclaimed PC-relative relocations left in data
  13 # CHECK: BOLT-INFO: marking main.cold.1 as a fragment of main
  14   .text
  15   .globl main
  16   .type main, %function
  17   .p2align 2
  18 main:
  19 LBB0:
  20   andl $0xf, %ecx
  21   cmpb $0x4, %cl
  22   # exit through abort in main.cold.1, registers cold fragment the regular way
  23   ja main.cold.1
  24
  25 # jump table dispatch, jumping to label indexed by val in %ecx
  26 LBB1:
  27   leaq JUMP_TABLE(%rip), %r8
  28   movzbl %cl, %ecx
  29   movslq (%r8,%rcx,4), %rax
  30   addq %rax, %r8
  31   jmpq *%r8
  32
  33 LBB2:
  34   xorq %rax, %rax
  35 LBB3:
  36   addq $0x8, %rsp
  37   ret
  38 .size main, .-main
  39
  40 # Insert padding between functions, so that the next instruction cannot be
  41 # treated as __builtin_unreachable destination for the jump table.
  42   .quad 0
  43
  44   .globl main.cold.1
  45   .type main.cold.1, %function
  46   .p2align 2
  47 main.cold.1:
  48 LBB4:
  49   callq abort
  50 .size main.cold.1, .-main.cold.1
  51
  52   .rodata
  53 # jmp table, entries must be R_X86_64_PC32 relocs
  54   .globl JUMP_TABLE
  55 JUMP_TABLE:
  56   .long LBB2-JUMP_TABLE
  57   .long LBB3-JUMP_TABLE
  58   .long LBB4-JUMP_TABLE
  59   .long LBB3-JUMP_TABLE
  60
  61 ## Verify that the entry corresponding to the cold fragment was added to
  62 ## the jump table.
  63
  64 # CHECK:      PIC Jump table
  65 # CHECK-NEXT: 0x{{.*}} :
  66 # CHECK-NEXT: 0x{{.*}} :
  67 # CHECK-NEXT: 0x{{.*}} : main.cold.1
  68 # CHECK-NEXT: 0x{{.*}} :