1; RUN: opt < %s -passes=globaldce -S | FileCheck %s 2 3target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128" 4 5declare { ptr, i1 } @llvm.type.checked.load(ptr, i32, metadata) 6 7; A vtable with "relative pointers", slots don't contain pointers to implementations, but instead have an i32 offset from the vtable itself to the implementation. 8@vtable = internal unnamed_addr constant { [2 x i32] } { [2 x i32] [ 9 i32 trunc (i64 sub (i64 ptrtoint (ptr @vfunc1_live to i64), i64 ptrtoint (ptr @vtable to i64)) to i32), 10 i32 trunc (i64 sub (i64 ptrtoint (ptr @vfunc2_dead to i64), i64 ptrtoint (ptr @vtable to i64)) to i32) 11]}, align 8, !type !0, !type !1, !vcall_visibility !{i64 2} 12!0 = !{i64 0, !"vfunc1.type"} 13!1 = !{i64 4, !"vfunc2.type"} 14 15; CHECK: @vtable = internal unnamed_addr constant { [2 x i32] } { [2 x i32] [ 16; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint (ptr @vfunc1_live to i64), i64 ptrtoint (ptr @vtable to i64)) to i32), 17; CHECK-SAME: i32 0 18; CHECK-SAME: ] }, align 8, !type !0, !type !1, !vcall_visibility !2 19 20; Similar to above, but the vtable is more aligned to how C++ relative vtables look. 21; That is, the functions may not be dso-local. 22@vtable2 = internal unnamed_addr constant { [2 x i32] } { [2 x i32] [ 23 i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @vfunc3_live_extern to i64), i64 ptrtoint (ptr @vtable2 to i64)) to i32), 24 i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @vfunc4_dead_extern to i64), i64 ptrtoint (ptr @vtable2 to i64)) to i32) 25]}, align 4, !type !3, !type !4, !vcall_visibility !{i64 2} 26!3 = !{i64 0, !"vfunc3.type"} 27!4 = !{i64 4, !"vfunc4.type"} 28 29; CHECK: @vtable2 = internal unnamed_addr constant { [2 x i32] } { [2 x i32] [ 30; CHECK-SAME: i32 trunc (i64 sub (i64 ptrtoint (ptr dso_local_equivalent @vfunc3_live_extern to i64), i64 ptrtoint (ptr @vtable2 to i64)) to i32), 31; CHECK-SAME: i32 0 32; CHECK-SAME: ] }, align 4, !type !3, !type !4, !vcall_visibility !2 33 34; (1) vfunc1_live is referenced from @main, stays alive 35define internal void @vfunc1_live() { 36 ; CHECK: define internal void @vfunc1_live( 37 ret void 38} 39 40; (2) vfunc2_dead is never referenced, gets removed and vtable slot is null'd 41define internal void @vfunc2_dead() { 42 ; CHECK-NOT: define internal void @vfunc2_dead( 43 ret void 44} 45 46; (3) vfunc3_live_extern is referenced from @main, stays alive 47; CHECK: declare void @vfunc3_live_extern 48declare void @vfunc3_live_extern() 49 50; (4) vfunc4_dead_extern is never referenced, gets removed and vtable slot is null'd 51; CHECK-NOT: declare void @vfunc4_dead_extern 52declare void @vfunc4_dead_extern() 53 54define void @main() { 55 %1 = ptrtoint ptr @vtable to i64 ; to keep @vtable alive 56 %2 = tail call { ptr, i1 } @llvm.type.checked.load(ptr null, i32 0, metadata !"vfunc1.type") 57 %3 = ptrtoint ptr @vtable2 to i64 ; to keep @vtable2 alive 58 %4 = tail call { ptr, i1 } @llvm.type.checked.load(ptr null, i32 0, metadata !"vfunc3.type") 59 ret void 60} 61 62!999 = !{i32 1, !"Virtual Function Elim", i32 1} 63!llvm.module.flags = !{!999} 64