# This reproduces a bug with shrink wrapping when moving # load instructions in-between the lock prefix and another # instruction (where the lock prefix applies). # REQUIRES: system-linux # RUN: llvm-mc -filetype=obj -triple x86_64-unknown-unknown \ # RUN: %s -o %t.o # RUN: link_fdata %s %t.o %t.fdata # Delete our BB symbols so BOLT doesn't mark them as entry points # RUN: llvm-strip --strip-unneeded %t.o # RUN: %clang %cflags -no-pie %t.o -o %t.exe -Wl,-q # RUN: llvm-bolt %t.exe --relocs=1 --frame-opt=all --print-fop \ # RUN: --print-only=main --data %t.fdata -o %t.out | FileCheck %s # RUN: %t.out 1 # CHECK: BOLT-INFO: Shrink wrapping moved 1 spills inserting load/stores and 0 spills inserting push/pops .text .globl main .type main, %function .p2align 4 main: # FDATA: 0 [unknown] 0 1 main 0 0 510 pushq %rbp movq %rsp, %rbp pushq %rbx # We save rbx here, but there is an # opportunity to move it to .LBB2 subq $0x18, %rsp cmpl $0x2, %edi .J1: jb .BBend # FDATA: 1 main #.J1# 1 main #.BB2# 0 10 # FDATA: 1 main #.J1# 1 main #.BBend# 0 500 .BB2: movq $2, %rbx # Use rbx in a cold block. Save rbx will be moved # just before this instruction. xorq %rax, %rax movb mystring, %al addq %rbx, %rax movb %al, mystring leaq mystring, %rdi callq puts lock add %r12,0x0(%rsp) # Put a lock in an unrelated instruction at the # dom. frontier where the restore will be moved to # We should not put the restore in-between the # lock and add! We typically avoid putting a # restore in the last BB instruction, but since # lock in llvm MC lib is considered a # separate instruction, we may mistakenly # put the restore just between these two. .BBend: addq $0x18, %rsp pop %rbx # Restore should be moved xorq %rax, %rax leaveq retq .size main, .-main .data mystring: .asciz "0 is rbx mod 10 contents in decimal\n"