## This reproduces an issue where two fragments of same function access same ## jump table, which means at least one fragment visits the other, i.e., one ## of them has split jump table. As a result, all of them will be marked as ## non-simple function. # REQUIRES: system-linux # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown %s -o %t.o # RUN: llvm-strip --strip-unneeded %t.o # RUN: %clang %cflags %t.o -o %t.exe -Wl,-q # RUN: llvm-bolt -print-cfg -v=3 %t.exe -o %t.out 2>&1 | FileCheck %s # CHECK: BOLT-INFO: multiple fragments access the same jump table: main; main.cold.1 # CHECK: PIC Jump table JUMP_TABLE1 for function main, main.cold.1 at {{.*}} with a total count of 0: .text .globl main .type main, %function .p2align 2 main: LBB0: andl $0xf, %ecx cmpb $0x4, %cl ## exit through ret ja LBB3 ## jump table dispatch, jumping to label indexed by val in %ecx LBB1: leaq JUMP_TABLE1(%rip), %r8 movzbl %cl, %ecx movslq (%r8,%rcx,4), %rax addq %rax, %r8 jmpq *%r8 LBB2: xorq %rax, %rax LBB3: addq $0x8, %rsp ret .size main, .-main ## cold fragment is only reachable .globl main.cold.1 .type main.cold.1, %function .p2align 2 main.cold.1: ## load bearing nop: pad LBB8 so that it can't be treated ## as __builtin_unreachable by analyzeJumpTable nop LBB4: andl $0xb, %ebx cmpb $0x1, %cl # exit through ret ja LBB7 ## jump table dispatch, jumping to label indexed by val in %ecx LBB5: leaq JUMP_TABLE1(%rip), %r8 movzbl %cl, %ecx movslq (%r8,%rcx,4), %rax addq %rax, %r8 jmpq *%r8 LBB6: xorq %rax, %rax LBB7: addq $0x8, %rsp ret LBB8: callq abort .size main.cold.1, .-main.cold.1 .rodata ## jmp table, entries must be R_X86_64_PC32 relocs .globl JUMP_TABLE1 JUMP_TABLE1: .long LBB2-JUMP_TABLE1 .long LBB3-JUMP_TABLE1 .long LBB8-JUMP_TABLE1 .long LBB6-JUMP_TABLE1 .long LBB7-JUMP_TABLE1