xref: /llvm-project/bolt/test/X86/split-func-jump-table-fragment-reverse.s (revision 11791ae7b0b05b8bd8d806331ff51da618912cf8)
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## The fragment is only reachable through jump table.
4
5# REQUIRES: system-linux
6
7# RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s -o %t.o
8# RUN: llvm-strip --strip-unneeded %t.o
9# RUN: %clang %cflags %t.o -o %t.exe -Wl,-q
10# RUN: llvm-bolt %t.exe -o %t.out --lite=0 -v=1 2>&1 | FileCheck %s
11
12# CHECK-NOT: unclaimed PC-relative relocations left in data
13# CHECK: BOLT-INFO: marking main.cold as a fragment of main
14  .text
15  .globl _start
16  .type _start, %function
17_start:
18  callq main.cold
19  call exit
20.size _start, .-_start
21
22  .globl main.cold
23  .type main.cold, %function
24  .p2align 2
25main.cold:
26LBB0:
27  andl $0xf, %ecx
28  cmpb $0x4, %cl
29  ## exit through ret
30  ja LBB3
31
32## jump table dispatch, jumping to label indexed by val in %ecx
33LBB1:
34  leaq JUMP_TABLE(%rip), %r8
35  movzbl %cl, %ecx
36  movslq (%r8,%rcx,4), %rax
37  addq %rax, %r8
38  jmpq *%r8
39
40LBB2:
41  xorq %rax, %rax
42LBB3:
43  addq $0x8, %rsp
44  ret
45.size main.cold, .-main.cold
46
47## main function, referenced from jump table in cold fragment
48  .globl main
49  .type main, %function
50  .p2align 2
51main:
52  ## load bearing nop: pad LBB4 so that it can't be treated
53  ## as __builtin_unreachable by analyzeJumpTable
54  nop
55LBB4:
56  callq abort
57.size main, .-main
58
59  .rodata
60## jmp table, entries must be R_X86_64_PC32 relocs
61  .globl JUMP_TABLE
62JUMP_TABLE:
63  .long LBB2-JUMP_TABLE
64  .long LBB3-JUMP_TABLE
65  .long LBB4-JUMP_TABLE
66  .long LBB3-JUMP_TABLE
67