bolt/test/X86/split-func-icf.s

   1 # This reproduces an issue where two cold fragments are folded into one, so the
   2 # fragment has two parents.
   3 # The fragment is only reachable through a jump table, so all functions must be
   4 # ignored.
   5
   6 # REQUIRES: system-linux
   7
   8 # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s -o %t.o
   9 # RUN: llvm-strip --strip-unneeded %t.o
  10 # RUN: %clang %cflags %t.o -o %t.exe -Wl,-q
  11 # RUN: llvm-bolt %t.exe -o %t.out -v=1 --print-only=main2.cold.1 --print-disasm 2>&1 | FileCheck %s
  12
  13 # CHECK-NOT: unclaimed PC-relative relocations left in data
  14 # CHECK-DAG: BOLT-INFO: marking main2.cold.1(*2) as a fragment of main2
  15 # CHECK-DAG: BOLT-INFO: marking main2.cold.1(*2) as a fragment of main
  16 # CHECK: Binary Function "main2.cold.1(*2)" after disassembly
  17 # CHECK: End of Function "main2.cold.1(*2)"
  18 # CHECK-DAG: BOLT-WARNING: Ignoring main2
  19 # CHECK-DAG: BOLT-WARNING: Ignoring main
  20 # CHECK-DAG: BOLT-WARNING: Ignoring main2.cold.1(*2)
  21 # CHECK: BOLT-WARNING: skipped 3 functions due to cold fragments
  22   .text
  23   .globl main
  24   .type main, %function
  25   .p2align 2
  26 main:
  27 LBB0:
  28   andl $0xf, %ecx
  29   cmpb $0x4, %cl
  30   # exit through ret
  31   ja LBB3
  32
  33 # jump table dispatch, jumping to label indexed by val in %ecx
  34 LBB1:
  35   leaq JUMP_TABLE1(%rip), %r8
  36   movzbl %cl, %ecx
  37   movslq (%r8,%rcx,4), %rax
  38   addq %rax, %r8
  39   jmpq *%r8
  40
  41 LBB2:
  42   xorq %rax, %rax
  43 LBB3:
  44   addq $0x8, %rsp
  45   ret
  46 .size main, .-main
  47
  48   .globl main2
  49   .type main2, %function
  50   .p2align 2
  51 main2:
  52 LBB20:
  53   andl $0xb, %ebx
  54   cmpb $0x1, %cl
  55   # exit through ret
  56   ja LBB23
  57
  58 # jump table dispatch, jumping to label indexed by val in %ecx
  59 LBB21:
  60   leaq JUMP_TABLE2(%rip), %r8
  61   movzbl %cl, %ecx
  62   movslq (%r8,%rcx,4), %rax
  63   addq %rax, %r8
  64   jmpq *%r8
  65
  66 LBB22:
  67   xorq %rax, %rax
  68 LBB23:
  69   addq $0x8, %rsp
  70   ret
  71 .size main2, .-main2
  72
  73 # cold fragment is only reachable through jump table
  74   .globl main2.cold.1
  75   .type main2.cold.1, %function
  76 main2.cold.1:
  77   .globl main.cold.1
  78   .type main.cold.1, %function
  79   .p2align 2
  80 main.cold.1:
  81   # load bearing nop: pad LBB4 so that it can't be treated
  82   # as __builtin_unreachable by analyzeJumpTable
  83   nop
  84 LBB4:
  85   callq abort
  86 .size main.cold.1, .-main.cold.1
  87
  88   .rodata
  89 # jmp table, entries must be R_X86_64_PC32 relocs
  90   .globl JUMP_TABLE1
  91 JUMP_TABLE1:
  92   .long LBB2-JUMP_TABLE1
  93   .long LBB3-JUMP_TABLE1
  94   .long LBB4-JUMP_TABLE1
  95   .long LBB3-JUMP_TABLE1
  96
  97   .globl JUMP_TABLE2
  98 JUMP_TABLE2:
  99   .long LBB22-JUMP_TABLE2
 100   .long LBB23-JUMP_TABLE2
 101   .long LBB4-JUMP_TABLE2
 102   .long LBB23-JUMP_TABLE2