diff options
5 files changed, 227 insertions, 8 deletions
diff --git a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp index f0cf5581ba8..d7c75049404 100644 --- a/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp +++ b/llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp @@ -841,17 +841,35 @@ bool DevirtIndex::tryFindVirtualCallTargets( std::vector<ValueInfo> &TargetsForSlot, const TypeIdCompatibleVtableInfo TIdInfo, uint64_t ByteOffset) { for (const TypeIdOffsetVtableInfo P : TIdInfo) { - // VTable initializer should have only one summary, or all copies must be - // linkonce/weak ODR. + // Ensure that we have at most one external linkage vtable initializer. assert(P.VTableVI.getSummaryList().size() == 1 || - llvm::all_of( + llvm::count_if( P.VTableVI.getSummaryList(), [&](const std::unique_ptr<GlobalValueSummary> &Summary) { - return GlobalValue::isLinkOnceODRLinkage(Summary->linkage()) || - GlobalValue::isWeakODRLinkage(Summary->linkage()); - })); - const auto *VS = cast<GlobalVarSummary>(P.VTableVI.getSummaryList()[0].get()); - if (!P.VTableVI.getSummaryList()[0]->isLive()) + return GlobalValue::isExternalLinkage(Summary->linkage()); + }) <= 1); + // Find the first non-available_externally linkage vtable initializer. + // We can have multiple available_externally, linkonce_odr and weak_odr + // vtable initializers, however we want to skip available_externally as they + // do not have type metadata attached, and therefore the summary will not + // contain any vtable functions. + // + // Also, handle the case of same-named local Vtables with the same path + // and therefore the same GUID. This can happen if there isn't enough + // distinguishing path when compiling the source file. In that case we + // conservatively return false early. + const GlobalVarSummary *VS = nullptr; + bool LocalFound = false; + for (auto &S : P.VTableVI.getSummaryList()) { + if (GlobalValue::isLocalLinkage(S->linkage())) { + if (LocalFound) + return false; + LocalFound = true; + } + if (!GlobalValue::isAvailableExternallyLinkage(S->linkage())) + VS = cast<GlobalVarSummary>(S.get()); + } + if (!VS->isLive()) continue; for (auto VTP : VS->vTableFuncs()) { if (VTP.VTableOffset != P.AddressPointOffset + ByteOffset) diff --git a/llvm/test/ThinLTO/X86/Inputs/devirt_available_externally.ll b/llvm/test/ThinLTO/X86/Inputs/devirt_available_externally.ll new file mode 100644 index 00000000000..56d6ea5fc99 --- /dev/null +++ b/llvm/test/ThinLTO/X86/Inputs/devirt_available_externally.ll @@ -0,0 +1,14 @@ +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-grtev4-linux-gnu" + +%struct.D = type { i32 (...)** } + +@_ZTV1D = constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%struct.D*, i32)* @_ZN1D1mEi to i8*)] }, !type !3 + +define i32 @_ZN1D1mEi(%struct.D* %this, i32 %a) #0 { + ret i32 0; +} + +attributes #0 = { noinline optnone } + +!3 = !{i64 16, !"_ZTS1D"} diff --git a/llvm/test/ThinLTO/X86/Inputs/devirt_local_same_guid.ll b/llvm/test/ThinLTO/X86/Inputs/devirt_local_same_guid.ll new file mode 100644 index 00000000000..cf3d024c32a --- /dev/null +++ b/llvm/test/ThinLTO/X86/Inputs/devirt_local_same_guid.ll @@ -0,0 +1,41 @@ +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-grtev4-linux-gnu" + +source_filename = "-" + +%struct.A = type { i32 (...)** } +%struct.B = type { %struct.A } + +@_ZTV1B = internal constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B1fEi to i8*), i8* bitcast (i32 (%struct.A*, i32)* @_ZN1A1nEi to i8*)] }, !type !0, !type !1 + +define internal i32 @_ZN1B1fEi(%struct.B* %this, i32 %a) #0 { + ret i32 0; +} + +define internal i32 @_ZN1A1nEi(%struct.A* %this, i32 %a) #0 { + ret i32 0; +} + +define i32 @test2(%struct.B* %obj, i32 %a) { +entry: + %0 = bitcast %struct.B* %obj to i8*** + %vtable2 = load i8**, i8*** %0 + %1 = bitcast i8** %vtable2 to i8* + %p2 = call i1 @llvm.type.test(i8* %1, metadata !"_ZTS1B") + call void @llvm.assume(i1 %p2) + + %fptrptr = getelementptr i8*, i8** %vtable2, i32 1 + %2 = bitcast i8** %fptrptr to i32 (%struct.B*, i32)** + %fptr33 = load i32 (%struct.B*, i32)*, i32 (%struct.B*, i32)** %2, align 8 + + %call4 = tail call i32 %fptr33(%struct.B* nonnull %obj, i32 %a) + ret i32 %call4 +} + +attributes #0 = { noinline optnone } + +declare i1 @llvm.type.test(i8*, metadata) +declare void @llvm.assume(i1) + +!0 = !{i64 16, !"_ZTS1A"} +!1 = !{i64 16, !"_ZTS1B"} diff --git a/llvm/test/ThinLTO/X86/devirt_available_externally.ll b/llvm/test/ThinLTO/X86/devirt_available_externally.ll new file mode 100644 index 00000000000..128055f7022 --- /dev/null +++ b/llvm/test/ThinLTO/X86/devirt_available_externally.ll @@ -0,0 +1,72 @@ +; REQUIRES: x86-registered-target + +; Test index-based devirtualization when first copy is available_externally, +; which doesn't have type metadata. We should use the strong external +; def in the other module to devirtualize. + +; Generate unsplit module with summary for ThinLTO index-based WPD. +; RUN: opt -thinlto-bc -o %t3.o %s +; RUN: opt -thinlto-bc -o %t4.o %p/Inputs/devirt_available_externally.ll + +; The available_externally copy should not get vTableFuncs information in its +; summary entry, but the external def should. +; RUN: llvm-dis -o - %t3.o | FileCheck %s --check-prefix=AVAILEXTERNAL +; AVAILEXTERNAL: gv: (name: "_ZTV1D" +; AVAILEXTERNAL-NOT: vTableFuncs +; AVAILEXTERNAL-SAME: ; guid = +; RUN: llvm-dis -o - %t4.o | FileCheck %s --check-prefix=EXTERNAL +; EXTERNAL: gv: (name: "_ZTV1D", {{.*}} vTableFuncs: ((virtFunc: + +; RUN: llvm-lto2 run %t3.o %t4.o -save-temps -pass-remarks=. \ +; RUN: -wholeprogramdevirt-print-index-based \ +; RUN: -o %t5 \ +; RUN: -r=%t3.o,test,px \ +; RUN: -r=%t3.o,_ZTV1D, \ +; RUN: -r=%t3.o,_ZN1D1mEi, \ +; RUN: -r=%t4.o,_ZN1D1mEi,p \ +; RUN: -r=%t4.o,_ZTV1D,px \ +; RUN: 2>&1 | FileCheck %s --check-prefix=REMARK --check-prefix=PRINT +; RUN: llvm-dis %t5.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR1 +; RUN: llvm-nm %t5.1 | FileCheck %s --check-prefix=NM-INDEX1 +; RUN: llvm-nm %t5.2 | FileCheck %s --check-prefix=NM-INDEX2 + +; NM-INDEX1-DAG: U _ZN1D1mEi + +; NM-INDEX2-DAG: T _ZN1D1mEi + +; PRINT-DAG: Devirtualized call to {{.*}} (_ZN1D1mEi) + +; REMARK-DAG: single-impl: devirtualized a call to _ZN1D1mEi + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-grtev4-linux-gnu" + +%struct.D = type { i32 (...)** } + +@_ZTV1D = available_externally constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%struct.D*, i32)* @_ZN1D1mEi to i8*)] } + +; CHECK-IR1-LABEL: define i32 @test +define i32 @test(%struct.D* %obj2, i32 %a) { +entry: + %0 = bitcast %struct.D* %obj2 to i8*** + %vtable2 = load i8**, i8*** %0 + %1 = bitcast i8** %vtable2 to i8* + %p2 = call i1 @llvm.type.test(i8* %1, metadata !"_ZTS1D") + call void @llvm.assume(i1 %p2) + + %2 = bitcast i8** %vtable2 to i32 (%struct.D*, i32)** + %fptr33 = load i32 (%struct.D*, i32)*, i32 (%struct.D*, i32)** %2, align 8 + + ; Check that the call was devirtualized. + ; CHECK-IR1: %call4 = tail call i32 @_ZN1D1mEi + %call4 = tail call i32 %fptr33(%struct.D* nonnull %obj2, i32 %a) + ret i32 %call4 +} +; CHECK-IR1-LABEL: ret i32 +; CHECK-IR1-LABEL: } + +declare i1 @llvm.type.test(i8*, metadata) +declare void @llvm.assume(i1) +declare i32 @_ZN1D1mEi(%struct.D* %this, i32 %a) + +attributes #0 = { noinline optnone } diff --git a/llvm/test/ThinLTO/X86/devirt_local_same_guid.ll b/llvm/test/ThinLTO/X86/devirt_local_same_guid.ll new file mode 100644 index 00000000000..8354bc19149 --- /dev/null +++ b/llvm/test/ThinLTO/X86/devirt_local_same_guid.ll @@ -0,0 +1,74 @@ +; REQUIRES: x86-registered-target + +; Test that index-based devirtualization in the presence of same-named +; local vtables in same named source files fails. + +; Generate unsplit module with summary for ThinLTO index-based WPD. +; RUN: opt -thinlto-bc -o %t3.o %s +; RUN: opt -thinlto-bc -o %t4.o %p/Inputs/devirt_local_same_guid.ll + +; RUN: llvm-lto2 run %t3.o %t4.o -save-temps -use-new-pm -pass-remarks=. \ +; RUN: -wholeprogramdevirt-print-index-based \ +; RUN: -o %t5 \ +; RUN: -r=%t3.o,use_B,px \ +; RUN: -r=%t3.o,test,px \ +; RUN: -r=%t4.o,test2,px +; RUN: llvm-dis %t5.1.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR1 +; RUN: llvm-dis %t5.2.4.opt.bc -o - | FileCheck %s --check-prefix=CHECK-IR2 + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128" +target triple = "x86_64-grtev4-linux-gnu" + +source_filename = "-" + +%struct.A = type { i32 (...)** } +%struct.B = type { %struct.A } + +@_ZTV1B = internal constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* undef, i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B1fEi to i8*), i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B1nEi to i8*)] }, !type !0, !type !1 + +define internal i32 @_ZN1B1fEi(%struct.B* %this, i32 %a) #0 { + ret i32 0; +} + +define internal i32 @_ZN1B1nEi(%struct.B* %this, i32 %a) #0 { + ret i32 0; +} + +; Ensures that vtable of B is live so that we will attempt devirt. +define dso_local i32 @use_B(%struct.B* %a) { +entry: + %0 = bitcast %struct.B* %a to i32 (...)*** + store i32 (...)** bitcast (i8** getelementptr inbounds ({ [4 x i8*] }, { [4 x i8*] }* @_ZTV1B, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8 + ret i32 0 +} + +; CHECK-IR1: define i32 @test( +define i32 @test(%struct.A* %obj, i32 %a) { +entry: + %0 = bitcast %struct.A* %obj to i8*** + %vtable = load i8**, i8*** %0 + %1 = bitcast i8** %vtable to i8* + %p = call i1 @llvm.type.test(i8* %1, metadata !"_ZTS1A") + call void @llvm.assume(i1 %p) + %fptrptr = getelementptr i8*, i8** %vtable, i32 1 + %2 = bitcast i8** %fptrptr to i32 (%struct.A*, i32)** + %fptr1 = load i32 (%struct.A*, i32)*, i32 (%struct.A*, i32)** %2, align 8 + + ; Check that the call was not devirtualized. + ; CHECK-IR1: %call = tail call i32 %fptr1 + %call = tail call i32 %fptr1(%struct.A* nonnull %obj, i32 %a) + + ret i32 %call +} + +; CHECK-IR2: define i32 @test2 +; Check that the call was not devirtualized. +; CHECK-IR2: %call4 = tail call i32 %fptr + +declare i1 @llvm.type.test(i8*, metadata) +declare void @llvm.assume(i1) + +attributes #0 = { noinline optnone } + +!0 = !{i64 16, !"_ZTS1A"} +!1 = !{i64 16, !"_ZTS1B"} |
