0f46e31cfb
As part of the migration to ptradd (https://discourse.llvm.org/t/rfc-replacing-getelementptr-with-ptradd/68699), we need to change the representation of the `inrange` attribute, which is used for vtable splitting. Currently, inrange is specified as follows: ``` getelementptr inbounds ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, inrange i32 1, i64 2) ``` The `inrange` is placed on a GEP index, and all accesses must be "in range" of that index. The new representation is as follows: ``` getelementptr inbounds inrange(-16, 16) ({ [4 x ptr], [4 x ptr] }, ptr @vt, i64 0, i32 1, i64 2) ``` This specifies which offsets are "in range" of the GEP result. The new representation will continue working when canonicalizing to ptradd representation: ``` getelementptr inbounds inrange(-16, 16) (i8, ptr @vt, i64 48) ``` The inrange offsets are relative to the return value of the GEP. An alternative design could make them relative to the source pointer instead. The result-relative format was chosen on the off-chance that we want to extend support to non-constant GEPs in the future, in which case this variant is more expressive. This implementation "upgrades" the old inrange representation in bitcode by simply dropping it. This is a very niche feature, and I don't think trying to upgrade it is worthwhile. Let me know if you disagree.
64 lines
2.2 KiB
LLVM
64 lines
2.2 KiB
LLVM
; RUN: opt < %s -passes=internalize -S | FileCheck %s
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%struct.A = type { ptr }
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%struct.B = type { ptr }
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%struct.C = type { ptr }
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; Class A has default visibility, so has no !vcall_visibility metadata before
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; or after LTO.
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; CHECK-NOT: @_ZTV1A = {{.*}}!vcall_visibility
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@_ZTV1A = dso_local unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr @_ZN1A3fooEv] }, align 8, !type !0, !type !1
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; Class B has hidden visibility but public LTO visibility, so has no
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; !vcall_visibility metadata before or after LTO.
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; CHECK-NOT: @_ZTV1B = {{.*}}!vcall_visibility
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@_ZTV1B = hidden unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr @_ZN1B3fooEv] }, align 8, !type !2, !type !3
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; Class C has hidden visibility, so the !vcall_visibility metadata is set to 1
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; (linkage unit) before LTO, and 2 (translation unit) after LTO.
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; CHECK: @_ZTV1C ={{.*}}!vcall_visibility [[MD_TU_VIS:![0-9]+]]
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@_ZTV1C = hidden unnamed_addr constant { [3 x ptr] } { [3 x ptr] [ptr null, ptr null, ptr @_ZN1C3fooEv] }, align 8, !type !4, !type !5, !vcall_visibility !6
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; Class D has translation unit visibility before LTO, and this is not changed
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; by LTO.
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; CHECK: @_ZTVN12_GLOBAL__N_11DE = {{.*}}!vcall_visibility [[MD_TU_VIS:![0-9]+]]
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@_ZTVN12_GLOBAL__N_11DE = internal unnamed_addr constant { [3 x ptr] } zeroinitializer, align 8, !type !7, !type !9, !vcall_visibility !11
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define dso_local void @_ZN1A3fooEv(ptr nocapture %this) {
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entry:
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ret void
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}
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define hidden void @_ZN1B3fooEv(ptr nocapture %this) {
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entry:
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ret void
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}
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define hidden void @_ZN1C3fooEv(ptr nocapture %this) {
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entry:
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ret void
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}
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define hidden noalias nonnull ptr @_Z6make_dv() {
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entry:
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%call = tail call ptr @_Znwm(i64 8) #3
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store ptr getelementptr inbounds inrange(-16, 8) ({ [3 x ptr] }, ptr @_ZTVN12_GLOBAL__N_11DE, i64 0, i32 0, i64 2), ptr %call, align 8
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ret ptr %call
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}
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declare dso_local noalias nonnull ptr @_Znwm(i64)
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; CHECK: [[MD_TU_VIS]] = !{i64 2}
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!0 = !{i64 16, !"_ZTS1A"}
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!1 = !{i64 16, !"_ZTSM1AFvvE.virtual"}
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!2 = !{i64 16, !"_ZTS1B"}
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!3 = !{i64 16, !"_ZTSM1BFvvE.virtual"}
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!4 = !{i64 16, !"_ZTS1C"}
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!5 = !{i64 16, !"_ZTSM1CFvvE.virtual"}
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!6 = !{i64 1}
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!7 = !{i64 16, !8}
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!8 = distinct !{}
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!9 = !{i64 16, !10}
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!10 = distinct !{}
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!11 = !{i64 2}
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