xref: /llvm-project/llvm/test/Transforms/GlobalDCE/virtual-functions-base-pointer-call.ll (revision 0f46e31cfbf415fcd3d3ce121bef94e92c6ccfc8) 
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
5; struct A {
6;   A();
7;   virtual int foo(int);
8;   virtual int bar(float);
9; };
10;
11; struct B : A {
12;   B();
13;   virtual int foo(int);
14;   virtual int bar(float);
15; };
16;
17; A::A() {}
18; B::B() {}
19; int A::foo(int)   { return 1; }
20; int A::bar(float) { return 2; }
21; int B::foo(int)   { return 3; }
22; int B::bar(float) { return 4; }
23;
24; extern "C" int test(A *p, int (A::*q)(int)) { return (p->*q)(42); }
25
26; Member function pointers are tracked by the combination of their object type
27; and function type, which must both be compatible. Here, the call is through a
28; pointer of type "int (A::*q)(int)", so the call could be dispatched to A::foo
29; or B::foo. It can't be dispatched to A::bar or B::bar as the function pointer
30; does not match, so those can be removed.
31
32%struct.A = type { ptr }
33%struct.B = type { %struct.A }
34
35; CHECK: @_ZTV1A = internal unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr null, ptr @_ZN1A3fooEi, ptr null] }
36@_ZTV1A = internal unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr null, ptr @_ZN1A3fooEi, ptr @_ZN1A3barEf] }, align 8, !type !0, !type !1, !type !2, !vcall_visibility !3
37; CHECK: @_ZTV1B = internal unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr null, ptr @_ZN1B3fooEi, ptr null] }
38@_ZTV1B = internal unnamed_addr constant { [4 x ptr] } { [4 x ptr] [ptr null, ptr null, ptr @_ZN1B3fooEi, ptr @_ZN1B3barEf] }, align 8, !type !0, !type !1, !type !2, !type !4, !type !5, !type !6, !vcall_visibility !3
39
40
41; CHECK: define internal i32 @_ZN1A3fooEi(
42define internal i32 @_ZN1A3fooEi(ptr nocapture readnone %this, i32) unnamed_addr #1 align 2 {
43entry:
44  ret i32 1
45}
46
47; CHECK-NOT: define internal i32 @_ZN1A3barEf(
48define internal i32 @_ZN1A3barEf(ptr nocapture readnone %this, float) unnamed_addr #1 align 2 {
49entry:
50  ret i32 2
51}
52
53; CHECK: define internal i32 @_ZN1B3fooEi(
54define internal i32 @_ZN1B3fooEi(ptr nocapture readnone %this, i32) unnamed_addr #1 align 2 {
55entry:
56  ret i32 3
57}
58
59; CHECK-NOT: define internal i32 @_ZN1B3barEf(
60define internal i32 @_ZN1B3barEf(ptr nocapture readnone %this, float) unnamed_addr #1 align 2 {
61entry:
62  ret i32 4
63}
64
65
66define hidden void @_ZN1AC2Ev(ptr nocapture %this) {
67entry:
68  store ptr getelementptr inbounds inrange(-16, 16) ({ [4 x ptr] }, ptr @_ZTV1A, i64 0, i32 0, i64 2), ptr %this, align 8
69  ret void
70}
71
72define hidden void @_ZN1BC2Ev(ptr nocapture %this) {
73entry:
74  store ptr getelementptr inbounds inrange(-16, 16) ({ [4 x ptr] }, ptr @_ZTV1B, i64 0, i32 0, i64 2), ptr %this, align 8
75  ret void
76}
77
78define hidden i32 @test(ptr %p, i64 %q.coerce0, i64 %q.coerce1) {
79entry:
80  %0 = getelementptr inbounds i8, ptr %p, i64 %q.coerce1
81  %1 = and i64 %q.coerce0, 1
82  %memptr.isvirtual = icmp eq i64 %1, 0
83  br i1 %memptr.isvirtual, label %memptr.nonvirtual, label %memptr.virtual
84
85memptr.virtual:                                   ; preds = %entry
86  %vtable = load ptr, ptr %0, align 8
87  %2 = add i64 %q.coerce0, -1
88  %3 = getelementptr i8, ptr %vtable, i64 %2, !nosanitize !12
89  %4 = tail call { ptr, i1 } @llvm.type.checked.load(ptr %3, i32 0, metadata !"_ZTSM1AFiiE.virtual"), !nosanitize !12
90  %5 = extractvalue { ptr, i1 } %4, 0, !nosanitize !12
91  br label %memptr.end
92
93memptr.nonvirtual:                                ; preds = %entry
94  %memptr.nonvirtualfn = inttoptr i64 %q.coerce0 to ptr
95  br label %memptr.end
96
97memptr.end:                                       ; preds = %memptr.nonvirtual, %memptr.virtual
98  %6 = phi ptr [ %5, %memptr.virtual ], [ %memptr.nonvirtualfn, %memptr.nonvirtual ]
99  %call = tail call i32 %6(ptr %0, i32 42)
100  ret i32 %call
101}
102
103declare { ptr, i1 } @llvm.type.checked.load(ptr, i32, metadata)
104
105!llvm.module.flags = !{!7}
106
107!0 = !{i64 16, !"_ZTS1A"}
108!1 = !{i64 16, !"_ZTSM1AFiiE.virtual"}
109!2 = !{i64 24, !"_ZTSM1AFifE.virtual"}
110!3 = !{i64 2}
111!4 = !{i64 16, !"_ZTS1B"}
112!5 = !{i64 16, !"_ZTSM1BFiiE.virtual"}
113!6 = !{i64 24, !"_ZTSM1BFifE.virtual"}
114!7 = !{i32 1, !"Virtual Function Elim", i32 1}
115!12 = !{}
116