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Revert "Dead Virtual Function Elimination" 

This reverts commit 9f6a873268.

llvm-svn: 374844
This commit is contained in:
Jorge Gorbe Moya 2019-10-14 23:25:25 +00:00
parent 3be9169caa
commit b052331bd6
34 changed files with 81 additions and 1426 deletions
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4
clang/include/clang/Basic/CodeGenOptions.def
View File

@ -278,10 +278,6 @@ CODEGENOPT(EmitLLVMUseLists, 1, 0) ///< Control whether to serialize use-lists.
CODEGENOPT(WholeProgramVTables, 1, 0) ///< Whether to apply whole-program
/// vtable optimization.
CODEGENOPT(VirtualFunctionElimination, 1, 0) ///< Whether to apply the dead
/// virtual function elimination
/// optimization.
/// Whether to use public LTO visibility for entities in std and stdext
/// namespaces. This is enabled by clang-cl's /MT and /MTd flags.
CODEGENOPT(LTOVisibilityPublicStd, 1, 0)

7
clang/include/clang/Driver/Options.td
View File

@ -1863,13 +1863,6 @@ def fforce_emit_vtables : Flag<["-"], "fforce-emit-vtables">, Group<f_Group>,
HelpText<"Emits more virtual tables to improve devirtualization">;
def fno_force_emit_vtables : Flag<["-"], "fno-force-emit-vtables">, Group<f_Group>,
Flags<[CoreOption]>;
def fvirtual_function_elimination : Flag<["-"], "fvirtual-function-elimination">, Group<f_Group>,
Flags<[CoreOption, CC1Option]>,
HelpText<"Enables dead virtual function elimination optimization. Requires -flto=full">;
def fno_virtual_function_elimination : Flag<["-"], "fno-virtual-function_elimination">, Group<f_Group>,
Flags<[CoreOption]>;
def fwrapv : Flag<["-"], "fwrapv">, Group<f_Group>, Flags<[CC1Option]>,
HelpText<"Treat signed integer overflow as two's complement">;
def fwritable_strings : Flag<["-"], "fwritable-strings">, Group<f_Group>, Flags<[CC1Option]>,

18
clang/lib/CodeGen/CGClass.cpp
View File

@ -2784,16 +2784,11 @@ void CodeGenFunction::EmitVTablePtrCheck(const CXXRecordDecl *RD,
bool CodeGenFunction::ShouldEmitVTableTypeCheckedLoad(const CXXRecordDecl *RD) {
if (!CGM.getCodeGenOpts().WholeProgramVTables ||
!SanOpts.has(SanitizerKind::CFIVCall) ||
!CGM.getCodeGenOpts().SanitizeTrap.has(SanitizerKind::CFIVCall) ||
!CGM.HasHiddenLTOVisibility(RD))
return false;
if (CGM.getCodeGenOpts().VirtualFunctionElimination)
return true;
if (!SanOpts.has(SanitizerKind::CFIVCall) ||
!CGM.getCodeGenOpts().SanitizeTrap.has(SanitizerKind::CFIVCall))
return false;
std::string TypeName = RD->getQualifiedNameAsString();
return !getContext().getSanitizerBlacklist().isBlacklistedType(
SanitizerKind::CFIVCall, TypeName);
@ -2816,13 +2811,8 @@ llvm::Value *CodeGenFunction::EmitVTableTypeCheckedLoad(
TypeId});
llvm::Value *CheckResult = Builder.CreateExtractValue(CheckedLoad, 1);
std::string TypeName = RD->getQualifiedNameAsString();
if (SanOpts.has(SanitizerKind::CFIVCall) &&
!getContext().getSanitizerBlacklist().isBlacklistedType(
SanitizerKind::CFIVCall, TypeName)) {
EmitCheck(std::make_pair(CheckResult, SanitizerKind::CFIVCall),
SanitizerHandler::CFICheckFail, {}, {});
}
EmitCheck(std::make_pair(CheckResult, SanitizerKind::CFIVCall),
SanitizerHandler::CFICheckFail, nullptr, nullptr);
return Builder.CreateBitCast(
Builder.CreateExtractValue(CheckedLoad, 0),

35
clang/lib/CodeGen/CGVTables.cpp
View File

@ -808,7 +808,7 @@ CodeGenVTables::GenerateConstructionVTable(const CXXRecordDecl *RD,
assert(!VTable->isDeclaration() && "Shouldn't set properties on declaration");
CGM.setGVProperties(VTable, RD);
CGM.EmitVTableTypeMetadata(RD, VTable, *VTLayout.get());
CGM.EmitVTableTypeMetadata(VTable, *VTLayout.get());
return VTable;
}
@ -1039,32 +1039,7 @@ bool CodeGenModule::HasHiddenLTOVisibility(const CXXRecordDecl *RD) {
return true;
}
llvm::GlobalObject::VCallVisibility
CodeGenModule::GetVCallVisibilityLevel(const CXXRecordDecl *RD) {
LinkageInfo LV = RD->getLinkageAndVisibility();
llvm::GlobalObject::VCallVisibility TypeVis;
if (!isExternallyVisible(LV.getLinkage()))
TypeVis = llvm::GlobalObject::VCallVisibilityTranslationUnit;
else if (HasHiddenLTOVisibility(RD))
TypeVis = llvm::GlobalObject::VCallVisibilityLinkageUnit;
else
TypeVis = llvm::GlobalObject::VCallVisibilityPublic;
for (auto B : RD->bases())
if (B.getType()->getAsCXXRecordDecl()->isDynamicClass())
TypeVis = std::min(TypeVis,
GetVCallVisibilityLevel(B.getType()->getAsCXXRecordDecl()));
for (auto B : RD->vbases())
if (B.getType()->getAsCXXRecordDecl()->isDynamicClass())
TypeVis = std::min(TypeVis,
GetVCallVisibilityLevel(B.getType()->getAsCXXRecordDecl()));
return TypeVis;
}
void CodeGenModule::EmitVTableTypeMetadata(const CXXRecordDecl *RD,
llvm::GlobalVariable *VTable,
void CodeGenModule::EmitVTableTypeMetadata(llvm::GlobalVariable *VTable,
const VTableLayout &VTLayout) {
if (!getCodeGenOpts().LTOUnit)
return;
@ -1124,10 +1099,4 @@ void CodeGenModule::EmitVTableTypeMetadata(const CXXRecordDecl *RD,
VTable->addTypeMetadata((PointerWidth * I).getQuantity(), MD);
}
}
if (getCodeGenOpts().VirtualFunctionElimination) {
llvm::GlobalObject::VCallVisibility TypeVis = GetVCallVisibilityLevel(RD);
if (TypeVis != llvm::GlobalObject::VCallVisibilityPublic)
VTable->addVCallVisibilityMetadata(TypeVis);
}
}

10
clang/lib/CodeGen/CodeGenModule.h
View File

@ -1280,16 +1280,8 @@ public:
/// optimization.
bool HasHiddenLTOVisibility(const CXXRecordDecl *RD);
/// Returns the vcall visibility of the given type. This is the scope in which
/// a virtual function call could be made which ends up being dispatched to a
/// member function of this class. This scope can be wider than the visibility
/// of the class itself when the class has a more-visible dynamic base class.
llvm::GlobalObject::VCallVisibility
GetVCallVisibilityLevel(const CXXRecordDecl *RD);
/// Emit type metadata for the given vtable using the given layout.
void EmitVTableTypeMetadata(const CXXRecordDecl *RD,
llvm::GlobalVariable *VTable,
void EmitVTableTypeMetadata(llvm::GlobalVariable *VTable,
const VTableLayout &VTLayout);
/// Generate a cross-DSO type identifier for MD.

101
clang/lib/CodeGen/ItaniumCXXABI.cpp
View File

@ -644,6 +644,8 @@ CGCallee ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(
VTableOffset = Builder.CreateTrunc(VTableOffset, CGF.Int32Ty);
VTableOffset = Builder.CreateZExt(VTableOffset, CGM.PtrDiffTy);
}
// Compute the address of the virtual function pointer.
llvm::Value *VFPAddr = Builder.CreateGEP(VTable, VTableOffset);
// Check the address of the function pointer if CFI on member function
// pointers is enabled.
@ -651,81 +653,44 @@ CGCallee ItaniumCXXABI::EmitLoadOfMemberFunctionPointer(
llvm::Constant *CheckTypeDesc;
bool ShouldEmitCFICheck = CGF.SanOpts.has(SanitizerKind::CFIMFCall) &&
CGM.HasHiddenLTOVisibility(RD);
bool ShouldEmitVFEInfo = CGM.getCodeGenOpts().VirtualFunctionElimination &&
CGM.HasHiddenLTOVisibility(RD);
llvm::Value *VirtualFn = nullptr;
{
if (ShouldEmitCFICheck) {
CodeGenFunction::SanitizerScope SanScope(&CGF);
llvm::Value *TypeId = nullptr;
llvm::Value *CheckResult = nullptr;
if (ShouldEmitCFICheck || ShouldEmitVFEInfo) {
// If doing CFI or VFE, we will need the metadata node to check against.
llvm::Metadata *MD =
CGM.CreateMetadataIdentifierForVirtualMemPtrType(QualType(MPT, 0));
TypeId = llvm::MetadataAsValue::get(CGF.getLLVMContext(), MD);
}
CheckSourceLocation = CGF.EmitCheckSourceLocation(E->getBeginLoc());
CheckTypeDesc = CGF.EmitCheckTypeDescriptor(QualType(MPT, 0));
llvm::Constant *StaticData[] = {
llvm::ConstantInt::get(CGF.Int8Ty, CodeGenFunction::CFITCK_VMFCall),
CheckSourceLocation,
CheckTypeDesc,
};
llvm::Value *VFPAddr = Builder.CreateGEP(VTable, VTableOffset);
llvm::Metadata *MD =
CGM.CreateMetadataIdentifierForVirtualMemPtrType(QualType(MPT, 0));
llvm::Value *TypeId = llvm::MetadataAsValue::get(CGF.getLLVMContext(), MD);
if (ShouldEmitVFEInfo) {
// If doing VFE, load from the vtable with a type.checked.load intrinsic
// call. Note that we use the GEP to calculate the address to load from
// and pass 0 as the offset to the intrinsic. This is because every
// vtable slot of the correct type is marked with matching metadata, and
// we know that the load must be from one of these slots.
llvm::Value *CheckedLoad = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::type_checked_load),
{VFPAddr, llvm::ConstantInt::get(CGM.Int32Ty, 0), TypeId});
CheckResult = Builder.CreateExtractValue(CheckedLoad, 1);
VirtualFn = Builder.CreateExtractValue(CheckedLoad, 0);
VirtualFn = Builder.CreateBitCast(VirtualFn, FTy->getPointerTo(),
"memptr.virtualfn");
llvm::Value *TypeTest = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::type_test), {VFPAddr, TypeId});
if (CGM.getCodeGenOpts().SanitizeTrap.has(SanitizerKind::CFIMFCall)) {
CGF.EmitTrapCheck(TypeTest);
} else {
// When not doing VFE, emit a normal load, as it allows more
// optimisations than type.checked.load.
if (ShouldEmitCFICheck) {
CheckResult = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::type_test),
{Builder.CreateBitCast(VFPAddr, CGF.Int8PtrTy), TypeId});
}
VFPAddr =
Builder.CreateBitCast(VFPAddr, FTy->getPointerTo()->getPointerTo());
VirtualFn = Builder.CreateAlignedLoad(VFPAddr, CGF.getPointerAlign(),
"memptr.virtualfn");
llvm::Value *AllVtables = llvm::MetadataAsValue::get(
CGM.getLLVMContext(),
llvm::MDString::get(CGM.getLLVMContext(), "all-vtables"));
llvm::Value *ValidVtable = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::type_test), {VTable, AllVtables});
CGF.EmitCheck(std::make_pair(TypeTest, SanitizerKind::CFIMFCall),
SanitizerHandler::CFICheckFail, StaticData,
{VTable, ValidVtable});
}
assert(VirtualFn && "Virtual fuction pointer not created!");
assert((!ShouldEmitCFICheck || !ShouldEmitVFEInfo || CheckResult) &&
"Check result required but not created!");
if (ShouldEmitCFICheck) {
// If doing CFI, emit the check.
CheckSourceLocation = CGF.EmitCheckSourceLocation(E->getBeginLoc());
CheckTypeDesc = CGF.EmitCheckTypeDescriptor(QualType(MPT, 0));
llvm::Constant *StaticData[] = {
llvm::ConstantInt::get(CGF.Int8Ty, CodeGenFunction::CFITCK_VMFCall),
CheckSourceLocation,
CheckTypeDesc,
};
if (CGM.getCodeGenOpts().SanitizeTrap.has(SanitizerKind::CFIMFCall)) {
CGF.EmitTrapCheck(CheckResult);
} else {
llvm::Value *AllVtables = llvm::MetadataAsValue::get(
CGM.getLLVMContext(),
llvm::MDString::get(CGM.getLLVMContext(), "all-vtables"));
llvm::Value *ValidVtable = Builder.CreateCall(
CGM.getIntrinsic(llvm::Intrinsic::type_test), {VTable, AllVtables});
CGF.EmitCheck(std::make_pair(CheckResult, SanitizerKind::CFIMFCall),
SanitizerHandler::CFICheckFail, StaticData,
{VTable, ValidVtable});
}
FnVirtual = Builder.GetInsertBlock();
}
} // End of sanitizer scope
FnVirtual = Builder.GetInsertBlock();
}
// Load the virtual function to call.
VFPAddr = Builder.CreateBitCast(VFPAddr, FTy->getPointerTo()->getPointerTo());
llvm::Value *VirtualFn = Builder.CreateAlignedLoad(
VFPAddr, CGF.getPointerAlign(), "memptr.virtualfn");
CGF.EmitBranch(FnEnd);
// In the non-virtual path, the function pointer is actually a
@ -1669,7 +1634,7 @@ void ItaniumCXXABI::emitVTableDefinitions(CodeGenVTables &CGVT,
EmitFundamentalRTTIDescriptors(RD);
if (!VTable->isDeclarationForLinker())
CGM.EmitVTableTypeMetadata(RD, VTable, VTLayout);
CGM.EmitVTableTypeMetadata(VTable, VTLayout);
}
bool ItaniumCXXABI::isVirtualOffsetNeededForVTableField(

27
clang/lib/Driver/ToolChains/Clang.cpp
View File

@ -5366,30 +5366,9 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
CmdArgs.push_back(Args.MakeArgString(TargetInfo.str()));
}
bool VirtualFunctionElimination =
Args.hasFlag(options::OPT_fvirtual_function_elimination,
options::OPT_fno_virtual_function_elimination, false);
if (VirtualFunctionElimination) {
// VFE requires full LTO (currently, this might be relaxed to allow ThinLTO
// in the future).
if (D.getLTOMode() != LTOK_Full)
D.Diag(diag::err_drv_argument_only_allowed_with)
<< "-fvirtual-function-elimination"
<< "-flto=full";
CmdArgs.push_back("-fvirtual-function-elimination");
}
// VFE requires whole-program-vtables, and enables it by default.
bool WholeProgramVTables = Args.hasFlag(
options::OPT_fwhole_program_vtables,
options::OPT_fno_whole_program_vtables, VirtualFunctionElimination);
if (VirtualFunctionElimination && !WholeProgramVTables) {
D.Diag(diag::err_drv_argument_not_allowed_with)
<< "-fno-whole-program-vtables"
<< "-fvirtual-function-elimination";
}
bool WholeProgramVTables =
Args.hasFlag(options::OPT_fwhole_program_vtables,
options::OPT_fno_whole_program_vtables, false);
if (WholeProgramVTables) {
if (!D.isUsingLTO())
D.Diag(diag::err_drv_argument_only_allowed_with)

2
clang/lib/Frontend/CompilerInvocation.cpp
View File

@ -758,8 +758,6 @@ static bool ParseCodeGenArgs(CodeGenOptions &Opts, ArgList &Args, InputKind IK,
Opts.CodeViewGHash = Args.hasArg(OPT_gcodeview_ghash);
Opts.MacroDebugInfo = Args.hasArg(OPT_debug_info_macro);
Opts.WholeProgramVTables = Args.hasArg(OPT_fwhole_program_vtables);
Opts.VirtualFunctionElimination =
Args.hasArg(OPT_fvirtual_function_elimination);
Opts.LTOVisibilityPublicStd = Args.hasArg(OPT_flto_visibility_public_std);
Opts.SplitDwarfFile = Args.getLastArgValue(OPT_split_dwarf_file);
Opts.SplitDwarfOutput = Args.getLastArgValue(OPT_split_dwarf_output);

88
clang/test/CodeGenCXX/vcall-visibility-metadata.cpp
View File

@ -1,88 +0,0 @@
// RUN: %clang_cc1 -flto -flto-unit -triple x86_64-unknown-linux -emit-llvm -fvirtual-function-elimination -fwhole-program-vtables -o - %s | FileCheck %s
// Anonymous namespace.
namespace {
// CHECK: @_ZTVN12_GLOBAL__N_11AE = {{.*}} !vcall_visibility [[VIS_TU:![0-9]+]]
struct A {
A() {}
virtual int f() { return 1; }
};
}
void *construct_A() {
return new A();
}
// Hidden visibility.
// CHECK: @_ZTV1B = {{.*}} !vcall_visibility [[VIS_DSO:![0-9]+]]
struct __attribute__((visibility("hidden"))) B {
B() {}
virtual int f() { return 1; }
};
B *construct_B() {
return new B();
}
// Default visibility.
// CHECK-NOT: @_ZTV1C = {{.*}} !vcall_visibility
struct __attribute__((visibility("default"))) C {
C() {}
virtual int f() { return 1; }
};
C *construct_C() {
return new C();
}
// Hidden visibility, public LTO visibility.
// CHECK-NOT: @_ZTV1D = {{.*}} !vcall_visibility
struct __attribute__((visibility("hidden"))) [[clang::lto_visibility_public]] D {
D() {}
virtual int f() { return 1; }
};
D *construct_D() {
return new D();
}
// Hidden visibility, but inherits from class with default visibility.
// CHECK-NOT: @_ZTV1E = {{.*}} !vcall_visibility
struct __attribute__((visibility("hidden"))) E : C {
E() {}
virtual int f() { return 1; }
};
E *construct_E() {
return new E();
}
// Anonymous namespace, but inherits from class with default visibility.
// CHECK-NOT: @_ZTVN12_GLOBAL__N_11FE = {{.*}} !vcall_visibility
namespace {
struct __attribute__((visibility("hidden"))) F : C {
F() {}
virtual int f() { return 1; }
};
}
void *construct_F() {
return new F();
}
// Anonymous namespace, but inherits from class with hidden visibility.
// CHECK: @_ZTVN12_GLOBAL__N_11GE = {{.*}} !vcall_visibility [[VIS_DSO:![0-9]+]]
namespace {
struct __attribute__((visibility("hidden"))) G : B {
G() {}
virtual int f() { return 1; }
};
}
void *construct_G() {
return new G();
}
// CHECK-DAG: [[VIS_DSO]] = !{i64 1}
// CHECK-DAG: [[VIS_TU]] = !{i64 2}

75
clang/test/CodeGenCXX/virtual-function-elimination.cpp
View File

@ -1,75 +0,0 @@
// RUN: %clang_cc1 -triple x86_64-unknown-linux -flto -flto-unit -fvirtual-function-elimination -fwhole-program-vtables -emit-llvm -o - %s | FileCheck %s
struct __attribute__((visibility("default"))) A {
virtual void foo();
};
void test_1(A *p) {
// A has default visibility, so no need for type.checked.load.
// CHECK-LABEL: define void @_Z6test_1P1A
// CHECK: [[FN_PTR_ADDR:%.+]] = getelementptr inbounds void (%struct.A*)*, void (%struct.A*)** {{%.+}}, i64 0
// CHECK: [[FN_PTR:%.+]] = load void (%struct.A*)*, void (%struct.A*)** [[FN_PTR_ADDR]]
// CHECK: call void [[FN_PTR]](
p->foo();
}
struct __attribute__((visibility("hidden"))) [[clang::lto_visibility_public]] B {
virtual void foo();
};
void test_2(B *p) {
// B has public LTO visibility, so no need for type.checked.load.
// CHECK-LABEL: define void @_Z6test_2P1B
// CHECK: [[FN_PTR_ADDR:%.+]] = getelementptr inbounds void (%struct.B*)*, void (%struct.B*)** {{%.+}}, i64 0
// CHECK: [[FN_PTR:%.+]] = load void (%struct.B*)*, void (%struct.B*)** [[FN_PTR_ADDR]]
// CHECK: call void [[FN_PTR]](
p->foo();
}
struct __attribute__((visibility("hidden"))) C {
virtual void foo();
virtual void bar();
};
void test_3(C *p) {
// C has hidden visibility, so we generate type.checked.load to allow VFE.
// CHECK-LABEL: define void @_Z6test_3P1C
// CHECK: [[LOAD:%.+]] = call { i8*, i1 } @llvm.type.checked.load(i8* {{%.+}}, i32 0, metadata !"_ZTS1C")
// CHECK: [[FN_PTR_I8:%.+]] = extractvalue { i8*, i1 } [[LOAD]], 0
// CHECK: [[FN_PTR:%.+]] = bitcast i8* [[FN_PTR_I8]] to void (%struct.C*)*
// CHECK: call void [[FN_PTR]](
p->foo();
}
void test_4(C *p) {
// When using type.checked.load, we pass the vtable offset to the intrinsic,
// rather than adding it to the pointer with a GEP.
// CHECK-LABEL: define void @_Z6test_4P1C
// CHECK: [[LOAD:%.+]] = call { i8*, i1 } @llvm.type.checked.load(i8* {{%.+}}, i32 8, metadata !"_ZTS1C")
// CHECK: [[FN_PTR_I8:%.+]] = extractvalue { i8*, i1 } [[LOAD]], 0
// CHECK: [[FN_PTR:%.+]] = bitcast i8* [[FN_PTR_I8]] to void (%struct.C*)*
// CHECK: call void [[FN_PTR]](
p->bar();
}
void test_5(C *p, void (C::*q)(void)) {
// We also use type.checked.load for the virtual side of member function
// pointer calls. We use a GEP to calculate the address to load from and pass
// 0 as the offset to the intrinsic, because we know that the load must be
// from exactly the point marked by one of the function-type metadatas (in
// this case "_ZTSM1CFvvE.virtual"). If we passed the offset from the member
// function pointer to the intrinsic, this information would be lost. No
// codegen changes on the non-virtual side.
// CHECK-LABEL: define void @_Z6test_5P1CMS_FvvE(
// CHECK: [[FN_PTR_ADDR:%.+]] = getelementptr i8, i8* %vtable, i64 {{%.+}}
// CHECK: [[LOAD:%.+]] = call { i8*, i1 } @llvm.type.checked.load(i8* [[FN_PTR_ADDR]], i32 0, metadata !"_ZTSM1CFvvE.virtual")
// CHECK: [[FN_PTR_I8:%.+]] = extractvalue { i8*, i1 } [[LOAD]], 0
// CHECK: [[FN_PTR:%.+]] = bitcast i8* [[FN_PTR_I8]] to void (%struct.C*)*
// CHECK: [[PHI:%.+]] = phi void (%struct.C*)* {{.*}}[ [[FN_PTR]], {{.*}} ]
// CHECK: call void [[PHI]](
(p->*q)();
}

11
clang/test/Driver/virtual-function-elimination.cpp
View File

@ -1,11 +0,0 @@
// RUN: %clang -target x86_64-unknown-linux -fvirtual-function-elimination -### %s 2>&1 | FileCheck --check-prefix=BAD-LTO %s
// RUN: %clang -target x86_64-unknown-linux -fvirtual-function-elimination -flto=thin -### %s 2>&1 | FileCheck --check-prefix=BAD-LTO %s
// BAD-LTO: invalid argument '-fvirtual-function-elimination' only allowed with '-flto=full'
// RUN: %clang -target x86_64-unknown-linux -fvirtual-function-elimination -flto -### %s 2>&1 | FileCheck --check-prefix=GOOD %s
// RUN: %clang -target x86_64-unknown-linux -fvirtual-function-elimination -flto=full -### %s 2>&1 | FileCheck --check-prefix=GOOD %s
// RUN: %clang -target x86_64-unknown-linux -fvirtual-function-elimination -flto -fwhole-program-vtables -### %s 2>&1 | FileCheck --check-prefix=GOOD %s
// GOOD: "-fvirtual-function-elimination" "-fwhole-program-vtables"
// RUN: %clang -target x86_64-unknown-linux -fvirtual-function-elimination -fno-whole-program-vtables -flto -### %s 2>&1 | FileCheck --check-prefix=NO-WHOLE-PROGRAM-VTABLES %s
// NO-WHOLE-PROGRAM-VTABLES: invalid argument '-fno-whole-program-vtables' not allowed with '-fvirtual-function-elimination'

9
llvm/docs/LangRef.rst
View File

@ -6264,13 +6264,6 @@ enum is the smallest type which can represent all of its values::
!0 = !{i32 1, !"short_wchar", i32 1}
!1 = !{i32 1, !"short_enum", i32 0}
LTO Post-Link Module Flags Metadata
-----------------------------------
Some optimisations are only when the entire LTO unit is present in the current
module. This is represented by the ``LTOPostLink`` module flags metadata, which
will be created with a value of ``1`` when LTO linking occurs.
Automatic Linker Flags Named Metadata
=====================================
@ -16816,8 +16809,6 @@ Overview:
The ``llvm.type.test`` intrinsic tests whether the given pointer is associated
with the given type identifier.
.. _type.checked.load:
'``llvm.type.checked.load``' Intrinsic
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

64
llvm/docs/TypeMetadata.rst
View File

@ -224,67 +224,3 @@ efficiently to minimize the sizes of the underlying bitsets.
}
.. _GlobalLayoutBuilder: https://github.com/llvm/llvm-project/blob/master/llvm/include/llvm/Transforms/IPO/LowerTypeTests.h
``!vcall_visibility`` Metadata
==============================
In order to allow removing unused function pointers from vtables, we need to
know whether every virtual call which could use it is known to the compiler, or
whether another translation unit could introduce more calls through the vtable.
This is not the same as the linkage of the vtable, because call sites could be
using a pointer of a more widely-visible base class. For example, consider this
code:
.. code-block:: c++
__attribute__((visibility("default")))
struct A {
virtual void f();
};
__attribute__((visibility("hidden")))
struct B : A {
virtual void f();
};
With LTO, we know that all code which can see the declaration of ``B`` is
visible to us. However, a pointer to a ``B`` could be cast to ``A*`` and passed
to another linkage unit, which could then call ``f`` on it. This call would
load from the vtable for ``B`` (using the object pointer), and then call
``B::f``. This means we can't remove the function pointer from ``B``'s vtable,
or the implementation of ``B::f``. However, if we can see all code which knows
about any dynamic base class (which would be the case if ``B`` only inherited
from classes with hidden visibility), then this optimisation would be valid.
This concept is represented in IR by the ``!vcall_visibility`` metadata
attached to vtable objects, with the following values:
.. list-table::
:header-rows: 1
:widths: 10 90
* - Value
- Behavior
* - 0 (or omitted)
- **Public**
Virtual function calls using this vtable could be made from external
code.
* - 1
- **Linkage Unit**
All virtual function calls which might use this vtable are in the
current LTO unit, meaning they will be in the current module once
LTO linking has been performed.
* - 2
- **Translation Unit**
All virtual function calls which might use this vtable are in the
current module.
In addition, all function pointer loads from a vtable marked with the
``!vcall_visibility`` metadata (with a non-zero value) must be done using the
:ref:`llvm.type.checked.load <type.checked.load>` intrinsic, so that virtual
calls sites can be correlated with the vtables which they might load from.
Other parts of the vtable (RTTI, offset-to-top, ...) can still be accessed with
normal loads.

2
llvm/include/llvm/Analysis/TypeMetadataUtils.h
View File

@ -50,8 +50,6 @@ void findDevirtualizableCallsForTypeCheckedLoad(
SmallVectorImpl<Instruction *> &LoadedPtrs,
SmallVectorImpl<Instruction *> &Preds, bool &HasNonCallUses,
const CallInst *CI, DominatorTree &DT);
Constant *getPointerAtOffset(Constant *I, uint64_t Offset, Module &M);
}
#endif

1
llvm/include/llvm/IR/FixedMetadataKinds.def
View File

@ -40,4 +40,3 @@ LLVM_FIXED_MD_KIND(MD_access_group, "llvm.access.group", 25)
LLVM_FIXED_MD_KIND(MD_callback, "callback", 26)
LLVM_FIXED_MD_KIND(MD_preserve_access_index, "llvm.preserve.access.index", 27)
LLVM_FIXED_MD_KIND(MD_misexpect, "misexpect", 28)
LLVM_FIXED_MD_KIND(MD_vcall_visibility, "vcall_visibility", 29)

16
llvm/include/llvm/IR/GlobalObject.h
View File

@ -28,20 +28,6 @@ class MDNode;
class Metadata;
class GlobalObject : public GlobalValue {
public:
// VCallVisibility - values for visibility metadata attached to vtables. This
// describes the scope in which a virtual call could end up being dispatched
// through this vtable.
enum VCallVisibility {
// Type is potentially visible to external code.
VCallVisibilityPublic = 0,
// Type is only visible to code which will be in the current Module after
// LTO internalization.
VCallVisibilityLinkageUnit = 1,
// Type is only visible to code in the current Module.
VCallVisibilityTranslationUnit = 2,
};
protected:
GlobalObject(Type *Ty, ValueTy VTy, Use *Ops, unsigned NumOps,
LinkageTypes Linkage, const Twine &Name,
@ -177,8 +163,6 @@ public:
void copyMetadata(const GlobalObject *Src, unsigned Offset);
void addTypeMetadata(unsigned Offset, Metadata *TypeID);
void addVCallVisibilityMetadata(VCallVisibility Visibility);
VCallVisibility getVCallVisibility() const;
protected:
void copyAttributesFrom(const GlobalObject *Src);

14
llvm/include/llvm/Transforms/IPO/GlobalDCE.h
View File

@ -43,25 +43,11 @@ private:
/// Comdat -> Globals in that Comdat section.
std::unordered_multimap<Comdat *, GlobalValue *> ComdatMembers;
/// !type metadata -> set of (vtable, offset) pairs
DenseMap<Metadata *, SmallSet<std::pair<GlobalVariable *, uint64_t>, 4>>
TypeIdMap;
// Global variables which are vtables, and which we have enough information
// about to safely do dead virtual function elimination.
SmallPtrSet<GlobalValue *, 32> VFESafeVTables;
void UpdateGVDependencies(GlobalValue &GV);
void MarkLive(GlobalValue &GV,
SmallVectorImpl<GlobalValue *> *Updates = nullptr);
bool RemoveUnusedGlobalValue(GlobalValue &GV);
// Dead virtual function elimination.
void AddVirtualFunctionDependencies(Module &M);
void ScanVTables(Module &M);
void ScanTypeCheckedLoadIntrinsics(Module &M);
void ScanVTableLoad(Function *Caller, Metadata *TypeId, uint64_t CallOffset);
void ComputeDependencies(Value *V, SmallPtrSetImpl<GlobalValue *> &U);
};

32
llvm/lib/Analysis/TypeMetadataUtils.cpp
View File

@ -127,35 +127,3 @@ void llvm::findDevirtualizableCallsForTypeCheckedLoad(
findCallsAtConstantOffset(DevirtCalls, &HasNonCallUses, LoadedPtr,
Offset->getZExtValue(), CI, DT);
}
Constant *llvm::getPointerAtOffset(Constant *I, uint64_t Offset, Module &M) {
if (I->getType()->isPointerTy()) {
if (Offset == 0)
return I;
return nullptr;
}
const DataLayout &DL = M.getDataLayout();
if (auto *C = dyn_cast<ConstantStruct>(I)) {
const StructLayout *SL = DL.getStructLayout(C->getType());
if (Offset >= SL->getSizeInBytes())
return nullptr;
unsigned Op = SL->getElementContainingOffset(Offset);
return getPointerAtOffset(cast<Constant>(I->getOperand(Op)),
Offset - SL->getElementOffset(Op), M);
}
if (auto *C = dyn_cast<ConstantArray>(I)) {
ArrayType *VTableTy = C->getType();
uint64_t ElemSize = DL.getTypeAllocSize(VTableTy->getElementType());
unsigned Op = Offset / ElemSize;
if (Op >= C->getNumOperands())
return nullptr;
return getPointerAtOffset(cast<Constant>(I->getOperand(Op)),
Offset % ElemSize, M);
}
return nullptr;
}

18
llvm/lib/IR/Metadata.cpp
View File

@ -1497,24 +1497,6 @@ void GlobalObject::addTypeMetadata(unsigned Offset, Metadata *TypeID) {
TypeID}));
}
void GlobalObject::addVCallVisibilityMetadata(VCallVisibility Visibility) {
addMetadata(LLVMContext::MD_vcall_visibility,
*MDNode::get(getContext(),
{ConstantAsMetadata::get(ConstantInt::get(
Type::getInt64Ty(getContext()), Visibility))}));
}
GlobalObject::VCallVisibility GlobalObject::getVCallVisibility() const {
if (MDNode *MD = getMetadata(LLVMContext::MD_vcall_visibility)) {
uint64_t Val = cast<ConstantInt>(
cast<ConstantAsMetadata>(MD->getOperand(0))->getValue())
->getZExtValue();
assert(Val <= 2 && "unknown vcall visibility!");
return (VCallVisibility)Val;
}
return VCallVisibility::VCallVisibilityPublic;
}
void Function::setSubprogram(DISubprogram *SP) {
setMetadata(LLVMContext::MD_dbg, SP);
}

2
llvm/lib/LTO/LTO.cpp
View File

@ -1003,8 +1003,6 @@ Error LTO::runRegularLTO(AddStreamFn AddStream) {
GV->setLinkage(GlobalValue::InternalLinkage);
}
RegularLTO.CombinedModule->addModuleFlag(Module::Error, "LTOPostLink", 1);
if (Conf.PostInternalizeModuleHook &&
!Conf.PostInternalizeModuleHook(0, *RegularLTO.CombinedModule))
return Error::success();

2
llvm/lib/LTO/LTOCodeGenerator.cpp
View File

@ -463,8 +463,6 @@ void LTOCodeGenerator::applyScopeRestrictions() {
internalizeModule(*MergedModule, mustPreserveGV);
MergedModule->addModuleFlag(Module::Error, "LTOPostLink", 1);
ScopeRestrictionsDone = true;
}

156
llvm/lib/Transforms/IPO/GlobalDCE.cpp
View File

@ -17,11 +17,9 @@
#include "llvm/Transforms/IPO/GlobalDCE.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/TypeMetadataUtils.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Operator.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/CtorUtils.h"
@ -31,15 +29,10 @@ using namespace llvm;
#define DEBUG_TYPE "globaldce"
static cl::opt<bool>
ClEnableVFE("enable-vfe", cl::Hidden, cl::init(true), cl::ZeroOrMore,
cl::desc("Enable virtual function elimination"));
STATISTIC(NumAliases , "Number of global aliases removed");
STATISTIC(NumFunctions, "Number of functions removed");
STATISTIC(NumIFuncs, "Number of indirect functions removed");
STATISTIC(NumVariables, "Number of global variables removed");
STATISTIC(NumVFuncs, "Number of virtual functions removed");
namespace {
class GlobalDCELegacyPass : public ModulePass {
@ -125,15 +118,6 @@ void GlobalDCEPass::UpdateGVDependencies(GlobalValue &GV) {
ComputeDependencies(User, Deps);
Deps.erase(&GV); // Remove self-reference.
for (GlobalValue *GVU : Deps) {
// If this is a dep from a vtable to a virtual function, and we have
// complete information about all virtual call sites which could call
// though this vtable, then skip it, because the call site information will
// be more precise.
if (VFESafeVTables.count(GVU) && isa<Function>(&GV)) {
LLVM_DEBUG(dbgs() << "Ignoring dep " << GVU->getName() << " -> "
<< GV.getName() << "\n");
continue;
}
GVDependencies[GVU].insert(&GV);
}
}
@ -148,133 +132,12 @@ void GlobalDCEPass::MarkLive(GlobalValue &GV,
if (Updates)
Updates->push_back(&GV);
if (Comdat *C = GV.getComdat()) {
for (auto &&CM : make_range(ComdatMembers.equal_range(C))) {
for (auto &&CM : make_range(ComdatMembers.equal_range(C)))
MarkLive(*CM.second, Updates); // Recursion depth is only two because only
// globals in the same comdat are visited.
}
}
}
void GlobalDCEPass::ScanVTables(Module &M) {
SmallVector<MDNode *, 2> Types;
LLVM_DEBUG(dbgs() << "Building type info -> vtable map\n");
auto *LTOPostLinkMD =
cast_or_null<ConstantAsMetadata>(M.getModuleFlag("LTOPostLink"));
bool LTOPostLink =
LTOPostLinkMD &&
(cast<ConstantInt>(LTOPostLinkMD->getValue())->getZExtValue() != 0);
for (GlobalVariable &GV : M.globals()) {
Types.clear();
GV.getMetadata(LLVMContext::MD_type, Types);
if (GV.isDeclaration() || Types.empty())
continue;
// Use the typeid metadata on the vtable to build a mapping from typeids to
// the list of (GV, offset) pairs which are the possible vtables for that
// typeid.
for (MDNode *Type : Types) {
Metadata *TypeID = Type->getOperand(1).get();
uint64_t Offset =
cast<ConstantInt>(
cast<ConstantAsMetadata>(Type->getOperand(0))->getValue())
->getZExtValue();
TypeIdMap[TypeID].insert(std::make_pair(&GV, Offset));
}
// If the type corresponding to the vtable is private to this translation
// unit, we know that we can see all virtual functions which might use it,
// so VFE is safe.
if (auto GO = dyn_cast<GlobalObject>(&GV)) {
GlobalObject::VCallVisibility TypeVis = GO->getVCallVisibility();
if (TypeVis == GlobalObject::VCallVisibilityTranslationUnit ||
(LTOPostLink &&
TypeVis == GlobalObject::VCallVisibilityLinkageUnit)) {
LLVM_DEBUG(dbgs() << GV.getName() << " is safe for VFE\n");
VFESafeVTables.insert(&GV);
}
}
}
}
void GlobalDCEPass::ScanVTableLoad(Function *Caller, Metadata *TypeId,
uint64_t CallOffset) {
for (auto &VTableInfo : TypeIdMap[TypeId]) {
GlobalVariable *VTable = VTableInfo.first;
uint64_t VTableOffset = VTableInfo.second;
Constant *Ptr =
getPointerAtOffset(VTable->getInitializer(), VTableOffset + CallOffset,
*Caller->getParent());
if (!Ptr) {
LLVM_DEBUG(dbgs() << "can't find pointer in vtable!\n");
VFESafeVTables.erase(VTable);
return;
}
auto Callee = dyn_cast<Function>(Ptr->stripPointerCasts());
if (!Callee) {
LLVM_DEBUG(dbgs() << "vtable entry is not function pointer!\n");
VFESafeVTables.erase(VTable);
return;
}
LLVM_DEBUG(dbgs() << "vfunc dep " << Caller->getName() << " -> "
<< Callee->getName() << "\n");
GVDependencies[Caller].insert(Callee);
}
}
void GlobalDCEPass::ScanTypeCheckedLoadIntrinsics(Module &M) {
LLVM_DEBUG(dbgs() << "Scanning type.checked.load intrinsics\n");
Function *TypeCheckedLoadFunc =
M.getFunction(Intrinsic::getName(Intrinsic::type_checked_load));
if (!TypeCheckedLoadFunc)
return;
for (auto U : TypeCheckedLoadFunc->users()) {
auto CI = dyn_cast<CallInst>(U);
if (!CI)
continue;
auto *Offset = dyn_cast<ConstantInt>(CI->getArgOperand(1));
Value *TypeIdValue = CI->getArgOperand(2);
auto *TypeId = cast<MetadataAsValue>(TypeIdValue)->getMetadata();
if (Offset) {
ScanVTableLoad(CI->getFunction(), TypeId, Offset->getZExtValue());
} else {
// type.checked.load with a non-constant offset, so assume every entry in
// every matching vtable is used.
for (auto &VTableInfo : TypeIdMap[TypeId]) {
VFESafeVTables.erase(VTableInfo.first);
}
}
}
}
void GlobalDCEPass::AddVirtualFunctionDependencies(Module &M) {
if (!ClEnableVFE)
return;
ScanVTables(M);
if (VFESafeVTables.empty())
return;
ScanTypeCheckedLoadIntrinsics(M);
LLVM_DEBUG(
dbgs() << "VFE safe vtables:\n";
for (auto *VTable : VFESafeVTables)
dbgs() << " " << VTable->getName() << "\n";
);
}
PreservedAnalyses GlobalDCEPass::run(Module &M, ModuleAnalysisManager &MAM) {
bool Changed = false;
@ -300,10 +163,6 @@ PreservedAnalyses GlobalDCEPass::run(Module &M, ModuleAnalysisManager &MAM) {
if (Comdat *C = GA.getComdat())
ComdatMembers.insert(std::make_pair(C, &GA));
// Add dependencies between virtual call sites and the virtual functions they
// might call, if we have that information.
AddVirtualFunctionDependencies(M);
// Loop over the module, adding globals which are obviously necessary.
for (GlobalObject &GO : M.global_objects()) {
Changed |= RemoveUnusedGlobalValue(GO);
@ -398,17 +257,8 @@ PreservedAnalyses GlobalDCEPass::run(Module &M, ModuleAnalysisManager &MAM) {
};
NumFunctions += DeadFunctions.size();
for (Function *F : DeadFunctions) {
if (!F->use_empty()) {
// Virtual functions might still be referenced by one or more vtables,
// but if we've proven them to be unused then it's safe to replace the
// virtual function pointers with null, allowing us to remove the
// function itself.
++NumVFuncs;
F->replaceAllUsesWith(ConstantPointerNull::get(F->getType()));
}
for (Function *F : DeadFunctions)
EraseUnusedGlobalValue(F);
}
NumVariables += DeadGlobalVars.size();
for (GlobalVariable *GV : DeadGlobalVars)
@ -427,8 +277,6 @@ PreservedAnalyses GlobalDCEPass::run(Module &M, ModuleAnalysisManager &MAM) {
ConstantDependenciesCache.clear();
GVDependencies.clear();
ComdatMembers.clear();
TypeIdMap.clear();
VFESafeVTables.clear();
if (Changed)
return PreservedAnalyses::none();

41
llvm/lib/Transforms/IPO/WholeProgramDevirt.cpp
View File

@ -496,6 +496,7 @@ struct DevirtModule {
void buildTypeIdentifierMap(
std::vector<VTableBits> &Bits,
DenseMap<Metadata *, std::set<TypeMemberInfo>> &TypeIdMap);
Constant *getPointerAtOffset(Constant *I, uint64_t Offset);
bool
tryFindVirtualCallTargets(std::vector<VirtualCallTarget> &TargetsForSlot,
const std::set<TypeMemberInfo> &TypeMemberInfos,
@ -812,6 +813,38 @@ void DevirtModule::buildTypeIdentifierMap(
}
}
Constant *DevirtModule::getPointerAtOffset(Constant *I, uint64_t Offset) {
if (I->getType()->isPointerTy()) {
if (Offset == 0)
return I;
return nullptr;
}
const DataLayout &DL = M.getDataLayout();
if (auto *C = dyn_cast<ConstantStruct>(I)) {
const StructLayout *SL = DL.getStructLayout(C->getType());
if (Offset >= SL->getSizeInBytes())
return nullptr;
unsigned Op = SL->getElementContainingOffset(Offset);
return getPointerAtOffset(cast<Constant>(I->getOperand(Op)),
Offset - SL->getElementOffset(Op));
}
if (auto *C = dyn_cast<ConstantArray>(I)) {
ArrayType *VTableTy = C->getType();
uint64_t ElemSize = DL.getTypeAllocSize(VTableTy->getElementType());
unsigned Op = Offset / ElemSize;
if (Op >= C->getNumOperands())
return nullptr;
return getPointerAtOffset(cast<Constant>(I->getOperand(Op)),
Offset % ElemSize);
}
return nullptr;
}
bool DevirtModule::tryFindVirtualCallTargets(
std::vector<VirtualCallTarget> &TargetsForSlot,
const std::set<TypeMemberInfo> &TypeMemberInfos, uint64_t ByteOffset) {
@ -820,7 +853,7 @@ bool DevirtModule::tryFindVirtualCallTargets(
return false;
Constant *Ptr = getPointerAtOffset(TM.Bits->GV->getInitializer(),
TM.Offset + ByteOffset, M);
TM.Offset + ByteOffset);
if (!Ptr)
return false;
@ -1908,12 +1941,6 @@ bool DevirtModule::run() {
for (VTableBits &B : Bits)
rebuildGlobal(B);
// We have lowered or deleted the type checked load intrinsics, so we no
// longer have enough information to reason about the liveness of virtual
// function pointers in GlobalDCE.
for (GlobalVariable &GV : M.globals())
GV.eraseMetadata(LLVMContext::MD_vcall_visibility);
return true;
}

19
llvm/test/LTO/ARM/lto-linking-metadata.ll
View File

@ -1,19 +0,0 @@
; RUN: opt %s -o %t1.bc
; RUN: llvm-lto %t1.bc -o %t1.save.opt -save-merged-module -O1 --exported-symbol=foo
; RUN: llvm-dis < %t1.save.opt.merged.bc | FileCheck %s
; RUN: llvm-lto2 run %t1.bc -o %t.out.o -save-temps \
; RUN: -r=%t1.bc,foo,pxl
; RUN: llvm-dis < %t.out.o.0.2.internalize.bc | FileCheck %s
target datalayout = "e-m:e-p:32:32-Fi8-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "armv7a-unknown-linux"
define void @foo() {
entry:
ret void
}
; CHECK: !llvm.module.flags = !{[[MD_NUM:![0-9]+]]}
; CHECK: [[MD_NUM]] = !{i32 1, !"LTOPostLink", i32 1}

4
llvm/test/ThinLTO/X86/lazyload_metadata.ll
View File

@ -10,13 +10,13 @@
; RUN: llvm-lto -thinlto-action=import %t2.bc -thinlto-index=%t3.bc \
; RUN: -o /dev/null -stats \
; RUN: 2>&1 | FileCheck %s -check-prefix=LAZY
; LAZY: 65 bitcode-reader - Number of Metadata records loaded
; LAZY: 63 bitcode-reader - Number of Metadata records loaded
; LAZY: 2 bitcode-reader - Number of MDStrings loaded
; RUN: llvm-lto -thinlto-action=import %t2.bc -thinlto-index=%t3.bc \
; RUN: -o /dev/null -disable-ondemand-mds-loading -stats \
; RUN: 2>&1 | FileCheck %s -check-prefix=NOTLAZY
; NOTLAZY: 74 bitcode-reader - Number of Metadata records loaded
; NOTLAZY: 72 bitcode-reader - Number of Metadata records loaded
; NOTLAZY: 7 bitcode-reader - Number of MDStrings loaded

78
llvm/test/Transforms/GlobalDCE/virtual-functions-base-call.ll
View File

@ -1,78 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
; struct A {
; A();
; virtual int foo();
; };
;
; struct B : A {
; B();
; virtual int foo();
; };
;
; A::A() {}
; B::B() {}
; int A::foo() { return 42; }
; int B::foo() { return 1337; }
;
; extern "C" int test(A *p) { return p->foo(); }
; The virtual call in test could be dispatched to either A::foo or B::foo, so
; both must be retained.
%struct.A = type { i32 (...)** }
%struct.B = type { %struct.A }
; CHECK: @_ZTV1A = internal unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*)* @_ZN1A3fooEv to i8*)] }
@_ZTV1A = internal unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*)* @_ZN1A3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !2
; CHECK: @_ZTV1B = internal unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*)* @_ZN1B3fooEv to i8*)] }
@_ZTV1B = internal unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*)* @_ZN1B3fooEv to i8*)] }, align 8, !type !0, !type !1, !type !3, !type !4, !vcall_visibility !2
; CHECK: define internal i32 @_ZN1A3fooEv(
define internal i32 @_ZN1A3fooEv(%struct.A* nocapture readnone %this) {
entry:
ret i32 42
}
; CHECK: define internal i32 @_ZN1B3fooEv(
define internal i32 @_ZN1B3fooEv(%struct.B* nocapture readnone %this) {
entry:
ret i32 1337
}
define hidden void @_ZN1AC2Ev(%struct.A* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.A, %struct.A* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
define hidden void @_ZN1BC2Ev(%struct.B* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.B, %struct.B* %this, i64 0, i32 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1B, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
define hidden i32 @test(%struct.A* %p) {
entry:
%0 = bitcast %struct.A* %p to i8**
%vtable1 = load i8*, i8** %0, align 8
%1 = tail call { i8*, i1 } @llvm.type.checked.load(i8* %vtable1, i32 0, metadata !"_ZTS1A"), !nosanitize !10
%2 = extractvalue { i8*, i1 } %1, 0, !nosanitize !10
%3 = bitcast i8* %2 to i32 (%struct.A*)*, !nosanitize !10
%call = tail call i32 %3(%struct.A* %p)
ret i32 %call
}
declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata) #2
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFivE.virtual"}
!2 = !{i64 2}
!3 = !{i64 16, !"_ZTS1B"}
!4 = !{i64 16, !"_ZTSM1BFivE.virtual"}
!10 = !{}

118
llvm/test/Transforms/GlobalDCE/virtual-functions-base-pointer-call.ll
View File

@ -1,118 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
; struct A {
; A();
; virtual int foo(int);
; virtual int bar(float);
; };
;
; struct B : A {
; B();
; virtual int foo(int);
; virtual int bar(float);
; };
;
; A::A() {}
; B::B() {}
; int A::foo(int) { return 1; }
; int A::bar(float) { return 2; }
; int B::foo(int) { return 3; }
; int B::bar(float) { return 4; }
;
; extern "C" int test(A *p, int (A::*q)(int)) { return (p->*q)(42); }
; Member function pointers are tracked by the combination of their object type
; and function type, which must both be compatible. Here, the call is through a
; pointer of type "int (A::*q)(int)", so the call could be dispatched to A::foo
; or B::foo. It can't be dispatched to A::bar or B::bar as the function pointer
; does not match, so those can be removed.
%struct.A = type { i32 (...)** }
%struct.B = type { %struct.A }
; CHECK: @_ZTV1A = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*, i32)* @_ZN1A3fooEi to i8*), i8* null] }
@_ZTV1A = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*, i32)* @_ZN1A3fooEi to i8*), i8* bitcast (i32 (%struct.A*, float)* @_ZN1A3barEf to i8*)] }, align 8, !type !0, !type !1, !type !2, !vcall_visibility !3
; CHECK: @_ZTV1B = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B3fooEi to i8*), i8* null] }
@_ZTV1B = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B3fooEi to i8*), i8* bitcast (i32 (%struct.B*, float)* @_ZN1B3barEf to i8*)] }, align 8, !type !0, !type !1, !type !2, !type !4, !type !5, !type !6, !vcall_visibility !3
; CHECK: define internal i32 @_ZN1A3fooEi(
define internal i32 @_ZN1A3fooEi(%struct.A* nocapture readnone %this, i32) unnamed_addr #1 align 2 {
entry:
ret i32 1
}
; CHECK-NOT: define internal i32 @_ZN1A3barEf(
define internal i32 @_ZN1A3barEf(%struct.A* nocapture readnone %this, float) unnamed_addr #1 align 2 {
entry:
ret i32 2
}
; CHECK: define internal i32 @_ZN1B3fooEi(
define internal i32 @_ZN1B3fooEi(%struct.B* nocapture readnone %this, i32) unnamed_addr #1 align 2 {
entry:
ret i32 3
}
; CHECK-NOT: define internal i32 @_ZN1B3barEf(
define internal i32 @_ZN1B3barEf(%struct.B* nocapture readnone %this, float) unnamed_addr #1 align 2 {
entry:
ret i32 4
}
define hidden void @_ZN1AC2Ev(%struct.A* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.A, %struct.A* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [4 x i8*] }, { [4 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
define hidden void @_ZN1BC2Ev(%struct.B* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.B, %struct.B* %this, i64 0, i32 0, i32 0
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 void
}
define hidden i32 @test(%struct.A* %p, i64 %q.coerce0, i64 %q.coerce1) {
entry:
%0 = bitcast %struct.A* %p to i8*
%1 = getelementptr inbounds i8, i8* %0, i64 %q.coerce1
%this.adjusted = bitcast i8* %1 to %struct.A*
%2 = and i64 %q.coerce0, 1
%memptr.isvirtual = icmp eq i64 %2, 0
br i1 %memptr.isvirtual, label %memptr.nonvirtual, label %memptr.virtual
memptr.virtual: ; preds = %entry
%3 = bitcast i8* %1 to i8**
%vtable = load i8*, i8** %3, align 8
%4 = add i64 %q.coerce0, -1
%5 = getelementptr i8, i8* %vtable, i64 %4, !nosanitize !12
%6 = tail call { i8*, i1 } @llvm.type.checked.load(i8* %5, i32 0, metadata !"_ZTSM1AFiiE.virtual"), !nosanitize !12
%7 = extractvalue { i8*, i1 } %6, 0, !nosanitize !12
%memptr.virtualfn = bitcast i8* %7 to i32 (%struct.A*, i32)*, !nosanitize !12
br label %memptr.end
memptr.nonvirtual: ; preds = %entry
%memptr.nonvirtualfn = inttoptr i64 %q.coerce0 to i32 (%struct.A*, i32)*
br label %memptr.end
memptr.end: ; preds = %memptr.nonvirtual, %memptr.virtual
%8 = phi i32 (%struct.A*, i32)* [ %memptr.virtualfn, %memptr.virtual ], [ %memptr.nonvirtualfn, %memptr.nonvirtual ]
%call = tail call i32 %8(%struct.A* %this.adjusted, i32 42)
ret i32 %call
}
declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata)
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFiiE.virtual"}
!2 = !{i64 24, !"_ZTSM1AFifE.virtual"}
!3 = !{i64 2}
!4 = !{i64 16, !"_ZTS1B"}
!5 = !{i64 16, !"_ZTSM1BFiiE.virtual"}
!6 = !{i64 24, !"_ZTSM1BFifE.virtual"}
!12 = !{}

78
llvm/test/Transforms/GlobalDCE/virtual-functions-derived-call.ll
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@ -1,78 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
; struct A {
; A();
; virtual int foo();
; };
;
; struct B : A {
; B();
; virtual int foo();
; };
;
; A::A() {}
; B::B() {}
; int A::foo() { return 42; }
; int B::foo() { return 1337; }
;
; extern "C" int test(B *p) { return p->foo(); }
; The virtual call in test can only be dispatched to B::foo (or a more-derived
; class, if there was one), so A::foo can be removed.
%struct.A = type { i32 (...)** }
%struct.B = type { %struct.A }
; CHECK: @_ZTV1A = internal unnamed_addr constant { [3 x i8*] } zeroinitializer
@_ZTV1A = internal unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*)* @_ZN1A3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !2
; CHECK: @_ZTV1B = internal unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*)* @_ZN1B3fooEv to i8*)] }
@_ZTV1B = internal unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*)* @_ZN1B3fooEv to i8*)] }, align 8, !type !0, !type !1, !type !3, !type !4, !vcall_visibility !2
; CHECK-NOT: define internal i32 @_ZN1A3fooEv(
define internal i32 @_ZN1A3fooEv(%struct.A* nocapture readnone %this) {
entry:
ret i32 42
}
; CHECK: define internal i32 @_ZN1B3fooEv(
define internal i32 @_ZN1B3fooEv(%struct.B* nocapture readnone %this) {
entry:
ret i32 1337
}
define hidden void @_ZN1AC2Ev(%struct.A* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.A, %struct.A* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
define hidden void @_ZN1BC2Ev(%struct.B* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.B, %struct.B* %this, i64 0, i32 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1B, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
define hidden i32 @test(%struct.B* %p) {
entry:
%0 = bitcast %struct.B* %p to i8**
%vtable1 = load i8*, i8** %0, align 8
%1 = tail call { i8*, i1 } @llvm.type.checked.load(i8* %vtable1, i32 0, metadata !"_ZTS1B"), !nosanitize !10
%2 = extractvalue { i8*, i1 } %1, 0, !nosanitize !10
%3 = bitcast i8* %2 to i32 (%struct.B*)*, !nosanitize !10
%call = tail call i32 %3(%struct.B* %p)
ret i32 %call
}
declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata) #2
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFivE.virtual"}
!2 = !{i64 2}
!3 = !{i64 16, !"_ZTS1B"}
!4 = !{i64 16, !"_ZTSM1BFivE.virtual"}
!10 = !{}

120
llvm/test/Transforms/GlobalDCE/virtual-functions-derived-pointer-call.ll
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@ -1,120 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
; struct A {
; A();
; virtual int foo(int);
; virtual int bar(float);
; };
;
; struct B : A {
; B();
; virtual int foo(int);
; virtual int bar(float);
; };
;
; A::A() {}
; B::B() {}
; int A::foo(int) { return 1; }
; int A::bar(float) { return 2; }
; int B::foo(int) { return 3; }
; int B::bar(float) { return 4; }
;
; extern "C" int test(B *p, int (B::*q)(int)) { return (p->*q)(42); }
; Member function pointers are tracked by the combination of their object type
; and function type, which must both be compatible. Here, the call is through a
; pointer of type "int (B::*q)(int)", so the call could only be dispatched to
; B::foo. It can't be dispatched to A::bar or B::bar as the function pointer
; does not match, and it can't be dispatched to A::foo as the object type
; doesn't match, so those can be removed.
%struct.A = type { i32 (...)** }
%struct.B = type { %struct.A }
; CHECK: @_ZTV1A = internal unnamed_addr constant { [4 x i8*] } zeroinitializer
@_ZTV1A = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*, i32)* @_ZN1A3fooEi to i8*), i8* bitcast (i32 (%struct.A*, float)* @_ZN1A3barEf to i8*)] }, align 8, !type !0, !type !1, !type !2, !vcall_visibility !3
; CHECK: @_ZTV1B = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B3fooEi to i8*), i8* null] }
@_ZTV1B = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.B*, i32)* @_ZN1B3fooEi to i8*), i8* bitcast (i32 (%struct.B*, float)* @_ZN1B3barEf to i8*)] }, align 8, !type !0, !type !1, !type !2, !type !4, !type !5, !type !6, !vcall_visibility !3
; CHECK-NOT: define internal i32 @_ZN1A3fooEi(
define internal i32 @_ZN1A3fooEi(%struct.A* nocapture readnone %this, i32) unnamed_addr #1 align 2 {
entry:
ret i32 1
}
; CHECK-NOT: define internal i32 @_ZN1A3barEf(
define internal i32 @_ZN1A3barEf(%struct.A* nocapture readnone %this, float) unnamed_addr #1 align 2 {
entry:
ret i32 2
}
; CHECK: define internal i32 @_ZN1B3fooEi(
define internal i32 @_ZN1B3fooEi(%struct.B* nocapture readnone %this, i32) unnamed_addr #1 align 2 {
entry:
ret i32 3
}
; CHECK-NOT: define internal i32 @_ZN1B3barEf(
define internal i32 @_ZN1B3barEf(%struct.B* nocapture readnone %this, float) unnamed_addr #1 align 2 {
entry:
ret i32 4
}
define hidden void @_ZN1AC2Ev(%struct.A* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.A, %struct.A* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [4 x i8*] }, { [4 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
define hidden void @_ZN1BC2Ev(%struct.B* nocapture %this) {
entry:
%0 = getelementptr inbounds %struct.B, %struct.B* %this, i64 0, i32 0, i32 0
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 void
}
define hidden i32 @test(%struct.B* %p, i64 %q.coerce0, i64 %q.coerce1) {
entry:
%0 = bitcast %struct.B* %p to i8*
%1 = getelementptr inbounds i8, i8* %0, i64 %q.coerce1
%this.adjusted = bitcast i8* %1 to %struct.B*
%2 = and i64 %q.coerce0, 1
%memptr.isvirtual = icmp eq i64 %2, 0
br i1 %memptr.isvirtual, label %memptr.nonvirtual, label %memptr.virtual
memptr.virtual: ; preds = %entry
%3 = bitcast i8* %1 to i8**
%vtable = load i8*, i8** %3, align 8
%4 = add i64 %q.coerce0, -1
%5 = getelementptr i8, i8* %vtable, i64 %4, !nosanitize !12
%6 = tail call { i8*, i1 } @llvm.type.checked.load(i8* %5, i32 0, metadata !"_ZTSM1BFiiE.virtual"), !nosanitize !12
%7 = extractvalue { i8*, i1 } %6, 0, !nosanitize !12
%memptr.virtualfn = bitcast i8* %7 to i32 (%struct.B*, i32)*, !nosanitize !12
br label %memptr.end
memptr.nonvirtual: ; preds = %entry
%memptr.nonvirtualfn = inttoptr i64 %q.coerce0 to i32 (%struct.B*, i32)*
br label %memptr.end
memptr.end: ; preds = %memptr.nonvirtual, %memptr.virtual
%8 = phi i32 (%struct.B*, i32)* [ %memptr.virtualfn, %memptr.virtual ], [ %memptr.nonvirtualfn, %memptr.nonvirtual ]
%call = tail call i32 %8(%struct.B* %this.adjusted, i32 42)
ret i32 %call
}
declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata)
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFiiE.virtual"}
!2 = !{i64 24, !"_ZTSM1AFifE.virtual"}
!3 = !{i64 2}
!4 = !{i64 16, !"_ZTS1B"}
!5 = !{i64 16, !"_ZTSM1BFiiE.virtual"}
!6 = !{i64 24, !"_ZTSM1BFifE.virtual"}
!12 = !{}

95
llvm/test/Transforms/GlobalDCE/virtual-functions-visibility-post-lto.ll
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@ -1,95 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
; structs A, B and C have vcall_visibility of public, linkage-unit and
; translation-unit respectively. This test is run after LTO linking (the
; LTOPostLink metadata is present), so B and C can be VFE'd.
target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
%struct.A = type { i32 (...)** }
@_ZTV1A = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.A*)* @_ZN1A3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !2
define internal void @_ZN1AC2Ev(%struct.A* %this) {
entry:
%0 = getelementptr inbounds %struct.A, %struct.A* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
; CHECK: define {{.*}} @_ZN1A3fooEv(
define internal void @_ZN1A3fooEv(%struct.A* nocapture %this) {
entry:
ret void
}
define dso_local i8* @_Z6make_Av() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.A*
tail call void @_ZN1AC2Ev(%struct.A* %0)
ret i8* %call
}
%struct.B = type { i32 (...)** }
@_ZTV1B = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.B*)* @_ZN1B3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !3
define internal void @_ZN1BC2Ev(%struct.B* %this) {
entry:
%0 = getelementptr inbounds %struct.B, %struct.B* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1B, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
; CHECK-NOT: define {{.*}} @_ZN1B3fooEv(
define internal void @_ZN1B3fooEv(%struct.B* nocapture %this) {
entry:
ret void
}
define dso_local i8* @_Z6make_Bv() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.B*
tail call void @_ZN1BC2Ev(%struct.B* %0)
ret i8* %call
}
%struct.C = type { i32 (...)** }
@_ZTV1C = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.C*)* @_ZN1C3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !4
define internal void @_ZN1CC2Ev(%struct.C* %this) {
entry:
%0 = getelementptr inbounds %struct.C, %struct.C* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1C, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
; CHECK-NOT: define {{.*}} @_ZN1C3fooEv(
define internal void @_ZN1C3fooEv(%struct.C* nocapture %this) {
entry:
ret void
}
define dso_local i8* @_Z6make_Cv() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.C*
tail call void @_ZN1CC2Ev(%struct.C* %0)
ret i8* %call
}
declare dso_local noalias nonnull i8* @_Znwm(i64)
!llvm.module.flags = !{!5}
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFvvE.virtual"}
!2 = !{i64 0} ; public vcall visibility
!3 = !{i64 1} ; linkage-unit vcall visibility
!4 = !{i64 2} ; translation-unit vcall visibility
!5 = !{i32 1, !"LTOPostLink", i32 1}

94
llvm/test/Transforms/GlobalDCE/virtual-functions-visibility-pre-lto.ll
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@ -1,94 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
; structs A, B and C have vcall_visibility of public, linkage-unit and
; translation-unit respectively. This test is run before LTO linking occurs
; (the LTOPostLink metadata is not present), so only C can be VFE'd.
target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
%struct.A = type { i32 (...)** }
@_ZTV1A = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.A*)* @_ZN1A3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !2
define internal void @_ZN1AC2Ev(%struct.A* %this) {
entry:
%0 = getelementptr inbounds %struct.A, %struct.A* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
; CHECK: define {{.*}} @_ZN1A3fooEv(
define internal void @_ZN1A3fooEv(%struct.A* nocapture %this) {
entry:
ret void
}
define dso_local i8* @_Z6make_Av() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.A*
tail call void @_ZN1AC2Ev(%struct.A* %0)
ret i8* %call
}
%struct.B = type { i32 (...)** }
@_ZTV1B = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.B*)* @_ZN1B3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !3
define internal void @_ZN1BC2Ev(%struct.B* %this) {
entry:
%0 = getelementptr inbounds %struct.B, %struct.B* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1B, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
; CHECK: define {{.*}} @_ZN1B3fooEv(
define internal void @_ZN1B3fooEv(%struct.B* nocapture %this) {
entry:
ret void
}
define dso_local i8* @_Z6make_Bv() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.B*
tail call void @_ZN1BC2Ev(%struct.B* %0)
ret i8* %call
}
%struct.C = type { i32 (...)** }
@_ZTV1C = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.C*)* @_ZN1C3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !4
define internal void @_ZN1CC2Ev(%struct.C* %this) {
entry:
%0 = getelementptr inbounds %struct.C, %struct.C* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1C, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
; CHECK-NOT: define {{.*}} @_ZN1C3fooEv(
define internal void @_ZN1C3fooEv(%struct.C* nocapture %this) {
entry:
ret void
}
define dso_local i8* @_Z6make_Cv() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.C*
tail call void @_ZN1CC2Ev(%struct.C* %0)
ret i8* %call
}
declare dso_local noalias nonnull i8* @_Znwm(i64)
!llvm.module.flags = !{}
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFvvE.virtual"}
!2 = !{i64 0} ; public vcall visibility
!3 = !{i64 1} ; linkage-unit vcall visibility
!4 = !{i64 2} ; translation-unit vcall visibility

55
llvm/test/Transforms/GlobalDCE/virtual-functions.ll
View File

@ -1,55 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
declare dso_local noalias nonnull i8* @_Znwm(i64)
declare { i8*, i1 } @llvm.type.checked.load(i8*, i32, metadata)
; %struct.A is a C++ struct with two virtual functions, A::foo and A::bar. The
; !vcall_visibility metadata is set on the vtable, so we know that all virtual
; calls through this vtable are visible and use the @llvm.type.checked.load
; intrinsic. Function test_A makes a call to A::foo, but there is no call to
; A::bar anywhere, so A::bar can be deleted, and its vtable slot replaced with
; null.
%struct.A = type { i32 (...)** }
; The pointer to A::bar in the vtable can be removed, because it will never be
; loaded. We replace it with null to keep the layout the same. Because it is at
; the end of the vtable we could potentially shrink the vtable, but don't
; currently do that.
; CHECK: @_ZTV1A = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*)* @_ZN1A3fooEv to i8*), i8* null] }
@_ZTV1A = internal unnamed_addr constant { [4 x i8*] } { [4 x i8*] [i8* null, i8* null, i8* bitcast (i32 (%struct.A*)* @_ZN1A3fooEv to i8*), i8* bitcast (i32 (%struct.A*)* @_ZN1A3barEv to i8*)] }, align 8, !type !0, !type !1, !type !2, !vcall_visibility !3
; A::foo is called, so must be retained.
; CHECK: define internal i32 @_ZN1A3fooEv(
define internal i32 @_ZN1A3fooEv(%struct.A* nocapture readnone %this) {
entry:
ret i32 42
}
; A::bar is not used, so can be deleted.
; CHECK-NOT: define internal i32 @_ZN1A3barEv(
define internal i32 @_ZN1A3barEv(%struct.A* nocapture readnone %this) {
entry:
ret i32 1337
}
define dso_local i32 @test_A() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.A*
%1 = bitcast i8* %call to i32 (...)***
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [4 x i8*] }, { [4 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %1, align 8
%2 = tail call { i8*, i1 } @llvm.type.checked.load(i8* bitcast (i8** getelementptr inbounds ({ [4 x i8*] }, { [4 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i8*), i32 0, metadata !"_ZTS1A"), !nosanitize !9
%3 = extractvalue { i8*, i1 } %2, 0, !nosanitize !9
%4 = bitcast i8* %3 to i32 (%struct.A*)*, !nosanitize !9
%call1 = tail call i32 %4(%struct.A* nonnull %0)
ret i32 %call1
}
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFivE.virtual"}
!2 = !{i64 24, !"_ZTSM1AFivE.virtual"}
!3 = !{i64 2}
!9 = !{}

47
llvm/test/Transforms/GlobalDCE/vtable-rtti.ll
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@ -1,47 +0,0 @@
; RUN: opt < %s -globaldce -S | FileCheck %s
; We currently only use llvm.type.checked.load for virtual function pointers,
; not any other part of the vtable, so we can't remove the RTTI pointer even if
; it's never going to be loaded from.
target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
%struct.A = type { i32 (...)** }
; CHECK: @_ZTV1A = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* bitcast ({ i8*, i8* }* @_ZTI1A to i8*), i8* null] }, align 8, !type !0, !type !1, !vcall_visibility !2
@_ZTV1A = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* bitcast ({ i8*, i8* }* @_ZTI1A to i8*), i8* bitcast (void (%struct.A*)* @_ZN1A3fooEv to i8*)] }, align 8, !type !0, !type !1, !vcall_visibility !2
@_ZTS1A = hidden constant [3 x i8] c"1A\00", align 1
@_ZTI1A = hidden constant { i8*, i8* } { i8* bitcast (i8** getelementptr inbounds (i8*, i8** @_ZTVN10__cxxabiv117__class_type_infoE, i64 2) to i8*), i8* getelementptr inbounds ([3 x i8], [3 x i8]* @_ZTS1A, i32 0, i32 0) }, align 8
define internal void @_ZN1AC2Ev(%struct.A* %this) {
entry:
%0 = getelementptr inbounds %struct.A, %struct.A* %this, i64 0, i32 0
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTV1A, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret void
}
; CHECK-NOT: define {{.*}} @_ZN1A3fooEv(
define internal void @_ZN1A3fooEv(%struct.A* nocapture %this) {
entry:
ret void
}
define dso_local i8* @_Z6make_Av() {
entry:
%call = tail call i8* @_Znwm(i64 8)
%0 = bitcast i8* %call to %struct.A*
tail call void @_ZN1AC2Ev(%struct.A* %0)
ret i8* %call
}
declare dso_local noalias nonnull i8* @_Znwm(i64)
@_ZTVN10__cxxabiv117__class_type_infoE = external dso_local global i8*
!llvm.module.flags = !{!3}
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFvvE.virtual"}
!2 = !{i64 2} ; translation-unit vcall visibility
!3 = !{i32 1, !"LTOPostLink", i32 1}

64
llvm/test/Transforms/Internalize/vcall-visibility.ll
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@ -1,64 +0,0 @@
; RUN: opt < %s -internalize -S | FileCheck %s
%struct.A = type { i32 (...)** }
%struct.B = type { i32 (...)** }
%struct.C = type { i32 (...)** }
; Class A has default visibility, so has no !vcall_visibility metadata before
; or after LTO.
; CHECK-NOT: @_ZTV1A = {{.*}}!vcall_visibility
@_ZTV1A = dso_local unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.A*)* @_ZN1A3fooEv to i8*)] }, align 8, !type !0, !type !1
; Class B has hidden visibility but public LTO visibility, so has no
; !vcall_visibility metadata before or after LTO.
; CHECK-NOT: @_ZTV1B = {{.*}}!vcall_visibility
@_ZTV1B = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.B*)* @_ZN1B3fooEv to i8*)] }, align 8, !type !2, !type !3
; Class C has hidden visibility, so the !vcall_visibility metadata is set to 1
; (linkage unit) before LTO, and 2 (translation unit) after LTO.
; CHECK: @_ZTV1C ={{.*}}!vcall_visibility [[MD_TU_VIS:![0-9]+]]
@_ZTV1C = hidden unnamed_addr constant { [3 x i8*] } { [3 x i8*] [i8* null, i8* null, i8* bitcast (void (%struct.C*)* @_ZN1C3fooEv to i8*)] }, align 8, !type !4, !type !5, !vcall_visibility !6
; Class D has translation unit visibility before LTO, and this is not changed
; by LTO.
; CHECK: @_ZTVN12_GLOBAL__N_11DE = {{.*}}!vcall_visibility [[MD_TU_VIS:![0-9]+]]
@_ZTVN12_GLOBAL__N_11DE = internal unnamed_addr constant { [3 x i8*] } zeroinitializer, align 8, !type !7, !type !9, !vcall_visibility !11
define dso_local void @_ZN1A3fooEv(%struct.A* nocapture %this) {
entry:
ret void
}
define hidden void @_ZN1B3fooEv(%struct.B* nocapture %this) {
entry:
ret void
}
define hidden void @_ZN1C3fooEv(%struct.C* nocapture %this) {
entry:
ret void
}
define hidden noalias nonnull i8* @_Z6make_dv() {
entry:
%call = tail call i8* @_Znwm(i64 8) #3
%0 = bitcast i8* %call to i32 (...)***
store i32 (...)** bitcast (i8** getelementptr inbounds ({ [3 x i8*] }, { [3 x i8*] }* @_ZTVN12_GLOBAL__N_11DE, i64 0, inrange i32 0, i64 2) to i32 (...)**), i32 (...)*** %0, align 8
ret i8* %call
}
declare dso_local noalias nonnull i8* @_Znwm(i64)
; CHECK: [[MD_TU_VIS]] = !{i64 2}
!0 = !{i64 16, !"_ZTS1A"}
!1 = !{i64 16, !"_ZTSM1AFvvE.virtual"}
!2 = !{i64 16, !"_ZTS1B"}
!3 = !{i64 16, !"_ZTSM1BFvvE.virtual"}
!4 = !{i64 16, !"_ZTS1C"}
!5 = !{i64 16, !"_ZTSM1CFvvE.virtual"}
!6 = !{i64 1}
!7 = !{i64 16, !8}
!8 = distinct !{}
!9 = !{i64 16, !10}
!10 = distinct !{}
!11 = !{i64 2}