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Use branch funnels for virtual calls when retpoline mitigation is enabled.

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The retpoline mitigation for variant 2 of CVE-2017-5715 inhibits the
branch predictor, and as a result it can lead to a measurable loss of
performance. We can reduce the performance impact of retpolined virtual
calls by replacing them with a special construct known as a branch
funnel, which is an instruction sequence that implements virtual calls
to a set of known targets using a binary tree of direct branches. This
allows the processor to speculately execute valid implementations of the
virtual function without allowing for speculative execution of of calls
to arbitrary addresses.

This patch extends the whole-program devirtualization pass to replace
certain virtual calls with calls to branch funnels, which are
represented using a new llvm.icall.jumptable intrinsic. It also extends
the LowerTypeTests pass to recognize the new intrinsic, generate code
for the branch funnels (x86_64 only for now) and lay out virtual tables
as required for each branch funnel.

The implementation supports full LTO as well as ThinLTO, and extends the
ThinLTO summary format used for whole-program devirtualization to
support branch funnels.

For more details see RFC:
http://lists.llvm.org/pipermail/llvm-dev/2018-January/120672.html

Differential Revision: https://reviews.llvm.org/D42453

llvm-svn: 327163
This commit is contained in:
Peter Collingbourne 2018-03-09 19:11:44 +00:00
parent fe81859a6a
commit 1834ad0e4a
17 changed files with 908 additions and 58 deletions
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6
include/llvm/ADT/PointerUnion.h
View File

@ -346,6 +346,12 @@ struct PointerLikeTypeTraits<PointerUnion3<PT1, PT2, PT3>> {
};
};
template <typename PT1, typename PT2, typename PT3>
bool operator<(PointerUnion3<PT1, PT2, PT3> lhs,
PointerUnion3<PT1, PT2, PT3> rhs) {
return lhs.getOpaqueValue() < rhs.getOpaqueValue();
}
/// A pointer union of four pointer types. See documentation for PointerUnion
/// for usage.
template <typename PT1, typename PT2, typename PT3, typename PT4>

2
include/llvm/CodeGen/TargetOpcodes.def
View File

@ -187,6 +187,8 @@ HANDLE_TARGET_OPCODE(PATCHABLE_TAIL_CALL)
/// patched to insert instrumentation instructions.
HANDLE_TARGET_OPCODE(PATCHABLE_EVENT_CALL)
HANDLE_TARGET_OPCODE(ICALL_BRANCH_FUNNEL)
/// The following generic opcodes are not supposed to appear after ISel.
/// This is something we might want to relax, but for now, this is convenient
/// to produce diagnostics.

4
include/llvm/IR/Intrinsics.td
View File

@ -874,6 +874,10 @@ def int_type_checked_load : Intrinsic<[llvm_ptr_ty, llvm_i1_ty],
[llvm_ptr_ty, llvm_i32_ty, llvm_metadata_ty],
[IntrNoMem]>;
// Create a branch funnel that implements an indirect call to a limited set of
// callees. This needs to be a musttail call.
def int_icall_branch_funnel : Intrinsic<[], [llvm_vararg_ty], []>;
def int_load_relative: Intrinsic<[llvm_ptr_ty], [llvm_ptr_ty, llvm_anyint_ty],
[IntrReadMem, IntrArgMemOnly]>;

7
include/llvm/IR/ModuleSummaryIndex.h
View File

@ -656,8 +656,11 @@ struct TypeTestResolution {
struct WholeProgramDevirtResolution {
enum Kind {
Indir, ///< Just do a regular virtual call
SingleImpl, ///< Single implementation devirtualization
Indir, ///< Just do a regular virtual call
SingleImpl, ///< Single implementation devirtualization
BranchFunnel, ///< When retpoline mitigation is enabled, use a branch funnel
///< that is defined in the merged module. Otherwise same as
///< Indir.
} TheKind = Indir;
std::string SingleImplName;

2
include/llvm/IR/ModuleSummaryIndexYAML.h
View File

@ -98,6 +98,8 @@ template <> struct ScalarEnumerationTraits<WholeProgramDevirtResolution::Kind> {
static void enumeration(IO &io, WholeProgramDevirtResolution::Kind &value) {
io.enumCase(value, "Indir", WholeProgramDevirtResolution::Indir);
io.enumCase(value, "SingleImpl", WholeProgramDevirtResolution::SingleImpl);
io.enumCase(value, "BranchFunnel",
WholeProgramDevirtResolution::BranchFunnel);
}
};

6
include/llvm/Target/Target.td
View File

@ -1140,6 +1140,12 @@ def FENTRY_CALL : StandardPseudoInstruction {
let mayStore = 1;
let hasSideEffects = 1;
}
def ICALL_BRANCH_FUNNEL : StandardPseudoInstruction {
let OutOperandList = (outs unknown:$dst);
let InOperandList = (ins variable_ops);
let AsmString = "";
let hasSideEffects = 1;
}
// Generic opcodes used in GlobalISel.
include "llvm/Target/GenericOpcodes.td"

54
lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
View File

@ -6043,6 +6043,60 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
case Intrinsic::experimental_vector_reduce_fmin:
visitVectorReduce(I, Intrinsic);
return nullptr;
case Intrinsic::icall_branch_funnel: {
SmallVector<SDValue, 16> Ops;
Ops.push_back(DAG.getRoot());
Ops.push_back(getValue(I.getArgOperand(0)));
int64_t Offset;
auto *Base = dyn_cast<GlobalObject>(GetPointerBaseWithConstantOffset(
I.getArgOperand(1), Offset, DAG.getDataLayout()));
if (!Base)
report_fatal_error(
"llvm.icall.branch.funnel operand must be a GlobalValue");
Ops.push_back(DAG.getTargetGlobalAddress(Base, getCurSDLoc(), MVT::i64, 0));
struct BranchFunnelTarget {
int64_t Offset;
SDValue Target;
};
SmallVector<BranchFunnelTarget, 8> Targets;
for (unsigned Op = 1, N = I.getNumArgOperands(); Op != N; Op += 2) {
auto *ElemBase = dyn_cast<GlobalObject>(GetPointerBaseWithConstantOffset(
I.getArgOperand(Op), Offset, DAG.getDataLayout()));
if (ElemBase != Base)
report_fatal_error("all llvm.icall.branch.funnel operands must refer "
"to the same GlobalValue");
SDValue Val = getValue(I.getArgOperand(Op + 1));
auto *GA = dyn_cast<GlobalAddressSDNode>(Val);
if (!GA)
report_fatal_error(
"llvm.icall.branch.funnel operand must be a GlobalValue");
Targets.push_back({Offset, DAG.getTargetGlobalAddress(
GA->getGlobal(), getCurSDLoc(),
Val.getValueType(), GA->getOffset())});
}
std::sort(Targets.begin(), Targets.end(),
[](const BranchFunnelTarget &T1, const BranchFunnelTarget &T2) {
return T1.Offset < T2.Offset;
});
for (auto &T : Targets) {
Ops.push_back(DAG.getTargetConstant(T.Offset, getCurSDLoc(), MVT::i32));
Ops.push_back(T.Target);
}
SDValue N(DAG.getMachineNode(TargetOpcode::ICALL_BRANCH_FUNNEL,
getCurSDLoc(), MVT::Other, Ops),
0);
DAG.setRoot(N);
setValue(&I, N);
HasTailCall = true;
return nullptr;
}
}
}

17
lib/IR/Verifier.cpp
View File

@ -2864,17 +2864,20 @@ void Verifier::verifyMustTailCall(CallInst &CI) {
Function *F = CI.getParent()->getParent();
FunctionType *CallerTy = F->getFunctionType();
FunctionType *CalleeTy = CI.getFunctionType();
Assert(CallerTy->getNumParams() == CalleeTy->getNumParams(),
"cannot guarantee tail call due to mismatched parameter counts", &CI);
if (!CI.getCalledFunction() || !CI.getCalledFunction()->isIntrinsic()) {
Assert(CallerTy->getNumParams() == CalleeTy->getNumParams(),
"cannot guarantee tail call due to mismatched parameter counts",
&CI);
for (int I = 0, E = CallerTy->getNumParams(); I != E; ++I) {
Assert(
isTypeCongruent(CallerTy->getParamType(I), CalleeTy->getParamType(I)),
"cannot guarantee tail call due to mismatched parameter types", &CI);
}
}
Assert(CallerTy->isVarArg() == CalleeTy->isVarArg(),
"cannot guarantee tail call due to mismatched varargs", &CI);
Assert(isTypeCongruent(CallerTy->getReturnType(), CalleeTy->getReturnType()),
"cannot guarantee tail call due to mismatched return types", &CI);
for (int I = 0, E = CallerTy->getNumParams(); I != E; ++I) {
Assert(
isTypeCongruent(CallerTy->getParamType(I), CalleeTy->getParamType(I)),
"cannot guarantee tail call due to mismatched parameter types", &CI);
}
// - The calling conventions of the caller and callee must match.
Assert(F->getCallingConv() == CI.getCallingConv(),

103
lib/Target/X86/X86ExpandPseudo.cpp
View File

@ -59,12 +59,112 @@ public:
}
private:
void ExpandICallBranchFunnel(MachineBasicBlock *MBB,
MachineBasicBlock::iterator MBBI);
bool ExpandMI(MachineBasicBlock &MBB, MachineBasicBlock::iterator MBBI);
bool ExpandMBB(MachineBasicBlock &MBB);
};
char X86ExpandPseudo::ID = 0;
} // End anonymous namespace.
void X86ExpandPseudo::ExpandICallBranchFunnel(
MachineBasicBlock *MBB, MachineBasicBlock::iterator MBBI) {
MachineBasicBlock *JTMBB = MBB;
MachineInstr *JTInst = &*MBBI;
MachineFunction *MF = MBB->getParent();
const BasicBlock *BB = MBB->getBasicBlock();
auto InsPt = MachineFunction::iterator(MBB);
++InsPt;
std::vector<std::pair<MachineBasicBlock *, unsigned>> TargetMBBs;
DebugLoc DL = JTInst->getDebugLoc();
MachineOperand Selector = JTInst->getOperand(0);
const GlobalValue *CombinedGlobal = JTInst->getOperand(1).getGlobal();
auto CmpTarget = [&](unsigned Target) {
BuildMI(*MBB, MBBI, DL, TII->get(X86::LEA64r), X86::R11)
.addReg(X86::RIP)
.addImm(1)
.addReg(0)
.addGlobalAddress(CombinedGlobal,
JTInst->getOperand(2 + 2 * Target).getImm())
.addReg(0);
BuildMI(*MBB, MBBI, DL, TII->get(X86::CMP64rr))
.add(Selector)
.addReg(X86::R11);
};
auto CreateMBB = [&]() {
auto *NewMBB = MF->CreateMachineBasicBlock(BB);
MBB->addSuccessor(NewMBB);
return NewMBB;
};
auto EmitCondJump = [&](unsigned Opcode, MachineBasicBlock *ThenMBB) {
BuildMI(*MBB, MBBI, DL, TII->get(Opcode)).addMBB(ThenMBB);
auto *ElseMBB = CreateMBB();
MF->insert(InsPt, ElseMBB);
MBB = ElseMBB;
MBBI = MBB->end();
};
auto EmitCondJumpTarget = [&](unsigned Opcode, unsigned Target) {
auto *ThenMBB = CreateMBB();
TargetMBBs.push_back({ThenMBB, Target});
EmitCondJump(Opcode, ThenMBB);
};
auto EmitTailCall = [&](unsigned Target) {
BuildMI(*MBB, MBBI, DL, TII->get(X86::TAILJMPd64))
.add(JTInst->getOperand(3 + 2 * Target));
};
std::function<void(unsigned, unsigned)> EmitBranchFunnel =
[&](unsigned FirstTarget, unsigned NumTargets) {
if (NumTargets == 1) {
EmitTailCall(FirstTarget);
return;
}
if (NumTargets == 2) {
CmpTarget(FirstTarget + 1);
EmitCondJumpTarget(X86::JB_1, FirstTarget);
EmitTailCall(FirstTarget + 1);
return;
}
if (NumTargets < 6) {
CmpTarget(FirstTarget + 1);
EmitCondJumpTarget(X86::JB_1, FirstTarget);
EmitCondJumpTarget(X86::JE_1, FirstTarget + 1);
EmitBranchFunnel(FirstTarget + 2, NumTargets - 2);
return;
}
auto *ThenMBB = CreateMBB();
CmpTarget(FirstTarget + (NumTargets / 2));
EmitCondJump(X86::JB_1, ThenMBB);
EmitCondJumpTarget(X86::JE_1, FirstTarget + (NumTargets / 2));
EmitBranchFunnel(FirstTarget + (NumTargets / 2) + 1,
NumTargets - (NumTargets / 2) - 1);
MF->insert(InsPt, ThenMBB);
MBB = ThenMBB;
MBBI = MBB->end();
EmitBranchFunnel(FirstTarget, NumTargets / 2);
};
EmitBranchFunnel(0, (JTInst->getNumOperands() - 2) / 2);
for (auto P : TargetMBBs) {
MF->insert(InsPt, P.first);
BuildMI(P.first, DL, TII->get(X86::TAILJMPd64))
.add(JTInst->getOperand(3 + 2 * P.second));
}
JTMBB->erase(JTInst);
}
/// If \p MBBI is a pseudo instruction, this method expands
/// it to the corresponding (sequence of) actual instruction(s).
/// \returns true if \p MBBI has been expanded.
@ -259,6 +359,9 @@ bool X86ExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
MBBI->eraseFromParent();
return true;
}
case TargetOpcode::ICALL_BRANCH_FUNNEL:
ExpandICallBranchFunnel(&MBB, MBBI);
return true;
}
llvm_unreachable("Previous switch has a fallthrough?");
}

117
lib/Transforms/IPO/LowerTypeTests.cpp
View File

@ -8,6 +8,8 @@
//===----------------------------------------------------------------------===//
//
// This pass lowers type metadata and calls to the llvm.type.test intrinsic.
// It also ensures that globals are properly laid out for the
// llvm.icall.branch.funnel intrinsic.
// See http://llvm.org/docs/TypeMetadata.html for more information.
//
//===----------------------------------------------------------------------===//
@ -25,6 +27,7 @@
#include "llvm/ADT/TinyPtrVector.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/TypeMetadataUtils.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constant.h"
@ -291,6 +294,29 @@ public:
}
};
struct ICallBranchFunnel final
: TrailingObjects<ICallBranchFunnel, GlobalTypeMember *> {
static ICallBranchFunnel *create(BumpPtrAllocator &Alloc, CallInst *CI,
ArrayRef<GlobalTypeMember *> Targets) {
auto *Call = static_cast<ICallBranchFunnel *>(
Alloc.Allocate(totalSizeToAlloc<GlobalTypeMember *>(Targets.size()),
alignof(ICallBranchFunnel)));
Call->CI = CI;
Call->NTargets = Targets.size();
std::uninitialized_copy(Targets.begin(), Targets.end(),
Call->getTrailingObjects<GlobalTypeMember *>());
return Call;
}
CallInst *CI;
ArrayRef<GlobalTypeMember *> targets() const {
return makeArrayRef(getTrailingObjects<GlobalTypeMember *>(), NTargets);
}
private:
size_t NTargets;
};
class LowerTypeTestsModule {
Module &M;
@ -372,6 +398,7 @@ class LowerTypeTestsModule {
const DenseMap<GlobalTypeMember *, uint64_t> &GlobalLayout);
Value *lowerTypeTestCall(Metadata *TypeId, CallInst *CI,
const TypeIdLowering &TIL);
void buildBitSetsFromGlobalVariables(ArrayRef<Metadata *> TypeIds,
ArrayRef<GlobalTypeMember *> Globals);
unsigned getJumpTableEntrySize();
@ -383,11 +410,13 @@ class LowerTypeTestsModule {
void buildBitSetsFromFunctions(ArrayRef<Metadata *> TypeIds,
ArrayRef<GlobalTypeMember *> Functions);
void buildBitSetsFromFunctionsNative(ArrayRef<Metadata *> TypeIds,
ArrayRef<GlobalTypeMember *> Functions);
ArrayRef<GlobalTypeMember *> Functions);
void buildBitSetsFromFunctionsWASM(ArrayRef<Metadata *> TypeIds,
ArrayRef<GlobalTypeMember *> Functions);
void buildBitSetsFromDisjointSet(ArrayRef<Metadata *> TypeIds,
ArrayRef<GlobalTypeMember *> Globals);
void
buildBitSetsFromDisjointSet(ArrayRef<Metadata *> TypeIds,
ArrayRef<GlobalTypeMember *> Globals,
ArrayRef<ICallBranchFunnel *> ICallBranchFunnels);
void replaceWeakDeclarationWithJumpTablePtr(Function *F, Constant *JT);
void moveInitializerToModuleConstructor(GlobalVariable *GV);
@ -1462,7 +1491,8 @@ void LowerTypeTestsModule::buildBitSetsFromFunctionsWASM(
}
void LowerTypeTestsModule::buildBitSetsFromDisjointSet(
ArrayRef<Metadata *> TypeIds, ArrayRef<GlobalTypeMember *> Globals) {
ArrayRef<Metadata *> TypeIds, ArrayRef<GlobalTypeMember *> Globals,
ArrayRef<ICallBranchFunnel *> ICallBranchFunnels) {
DenseMap<Metadata *, uint64_t> TypeIdIndices;
for (unsigned I = 0; I != TypeIds.size(); ++I)
TypeIdIndices[TypeIds[I]] = I;
@ -1471,15 +1501,25 @@ void LowerTypeTestsModule::buildBitSetsFromDisjointSet(
// the type identifier.
std::vector<std::set<uint64_t>> TypeMembers(TypeIds.size());
unsigned GlobalIndex = 0;
DenseMap<GlobalTypeMember *, uint64_t> GlobalIndices;
for (GlobalTypeMember *GTM : Globals) {
for (MDNode *Type : GTM->types()) {
// Type = { offset, type identifier }
unsigned TypeIdIndex = TypeIdIndices[Type->getOperand(1)];
TypeMembers[TypeIdIndex].insert(GlobalIndex);
auto I = TypeIdIndices.find(Type->getOperand(1));
if (I != TypeIdIndices.end())
TypeMembers[I->second].insert(GlobalIndex);
}
GlobalIndices[GTM] = GlobalIndex;
GlobalIndex++;
}
for (ICallBranchFunnel *JT : ICallBranchFunnels) {
TypeMembers.emplace_back();
std::set<uint64_t> &TMSet = TypeMembers.back();
for (GlobalTypeMember *T : JT->targets())
TMSet.insert(GlobalIndices[T]);
}
// Order the sets of indices by size. The GlobalLayoutBuilder works best
// when given small index sets first.
std::stable_sort(
@ -1567,8 +1607,11 @@ bool LowerTypeTestsModule::runForTesting(Module &M) {
bool LowerTypeTestsModule::lower() {
Function *TypeTestFunc =
M.getFunction(Intrinsic::getName(Intrinsic::type_test));
if ((!TypeTestFunc || TypeTestFunc->use_empty()) && !ExportSummary &&
!ImportSummary)
Function *ICallBranchFunnelFunc =
M.getFunction(Intrinsic::getName(Intrinsic::icall_branch_funnel));
if ((!TypeTestFunc || TypeTestFunc->use_empty()) &&
(!ICallBranchFunnelFunc || ICallBranchFunnelFunc->use_empty()) &&
!ExportSummary && !ImportSummary)
return false;
if (ImportSummary) {
@ -1580,6 +1623,10 @@ bool LowerTypeTestsModule::lower() {
}
}
if (ICallBranchFunnelFunc && !ICallBranchFunnelFunc->use_empty())
report_fatal_error(
"unexpected call to llvm.icall.branch.funnel during import phase");
SmallVector<Function *, 8> Defs;
SmallVector<Function *, 8> Decls;
for (auto &F : M) {
@ -1604,8 +1651,8 @@ bool LowerTypeTestsModule::lower() {
// Equivalence class set containing type identifiers and the globals that
// reference them. This is used to partition the set of type identifiers in
// the module into disjoint sets.
using GlobalClassesTy =
EquivalenceClasses<PointerUnion<GlobalTypeMember *, Metadata *>>;
using GlobalClassesTy = EquivalenceClasses<
PointerUnion3<GlobalTypeMember *, Metadata *, ICallBranchFunnel *>>;
GlobalClassesTy GlobalClasses;
// Verify the type metadata and build a few data structures to let us
@ -1688,14 +1735,13 @@ bool LowerTypeTestsModule::lower() {
}
}
DenseMap<GlobalObject *, GlobalTypeMember *> GlobalTypeMembers;
for (GlobalObject &GO : M.global_objects()) {
if (isa<GlobalVariable>(GO) && GO.isDeclarationForLinker())
continue;
Types.clear();
GO.getMetadata(LLVMContext::MD_type, Types);
if (Types.empty())
continue;
bool IsDefinition = !GO.isDeclarationForLinker();
bool IsExported = false;
@ -1706,6 +1752,7 @@ bool LowerTypeTestsModule::lower() {
auto *GTM =
GlobalTypeMember::create(Alloc, &GO, IsDefinition, IsExported, Types);
GlobalTypeMembers[&GO] = GTM;
for (MDNode *Type : Types) {
verifyTypeMDNode(&GO, Type);
auto &Info = TypeIdInfo[Type->getOperand(1)];
@ -1746,6 +1793,43 @@ bool LowerTypeTestsModule::lower() {
}
}
if (ICallBranchFunnelFunc) {
for (const Use &U : ICallBranchFunnelFunc->uses()) {
if (Arch != Triple::x86_64)
report_fatal_error(
"llvm.icall.branch.funnel not supported on this target");
auto CI = cast<CallInst>(U.getUser());
std::vector<GlobalTypeMember *> Targets;
if (CI->getNumArgOperands() % 2 != 1)
report_fatal_error("number of arguments should be odd");
GlobalClassesTy::member_iterator CurSet;
for (unsigned I = 1; I != CI->getNumArgOperands(); I += 2) {
int64_t Offset;
auto *Base = dyn_cast<GlobalObject>(GetPointerBaseWithConstantOffset(
CI->getOperand(I), Offset, M.getDataLayout()));
if (!Base)
report_fatal_error(
"Expected branch funnel operand to be global value");
GlobalTypeMember *GTM = GlobalTypeMembers[Base];
Targets.push_back(GTM);
GlobalClassesTy::member_iterator NewSet =
GlobalClasses.findLeader(GlobalClasses.insert(GTM));
if (I == 1)
CurSet = NewSet;
else
CurSet = GlobalClasses.unionSets(CurSet, NewSet);
}
GlobalClasses.unionSets(
CurSet, GlobalClasses.findLeader(GlobalClasses.insert(
ICallBranchFunnel::create(Alloc, CI, Targets))));
}
}
if (ExportSummary) {
DenseMap<GlobalValue::GUID, TinyPtrVector<Metadata *>> MetadataByGUID;
for (auto &P : TypeIdInfo) {
@ -1798,13 +1882,16 @@ bool LowerTypeTestsModule::lower() {
// Build the list of type identifiers in this disjoint set.
std::vector<Metadata *> TypeIds;
std::vector<GlobalTypeMember *> Globals;
std::vector<ICallBranchFunnel *> ICallBranchFunnels;
for (GlobalClassesTy::member_iterator MI =
GlobalClasses.member_begin(S.first);
MI != GlobalClasses.member_end(); ++MI) {
if ((*MI).is<Metadata *>())
if (MI->is<Metadata *>())
TypeIds.push_back(MI->get<Metadata *>());
else
else if (MI->is<GlobalTypeMember *>())
Globals.push_back(MI->get<GlobalTypeMember *>());
else
ICallBranchFunnels.push_back(MI->get<ICallBranchFunnel *>());
}
// Order type identifiers by global index for determinism. This ordering is
@ -1814,7 +1901,7 @@ bool LowerTypeTestsModule::lower() {
});
// Build bitsets for this disjoint set.
buildBitSetsFromDisjointSet(TypeIds, Globals);
buildBitSetsFromDisjointSet(TypeIds, Globals, ICallBranchFunnels);
}
allocateByteArrays();

211
lib/Transforms/IPO/WholeProgramDevirt.cpp
View File

@ -316,12 +316,17 @@ struct CallSiteInfo {
/// cases we are directly operating on the call sites at the IR level.
std::vector<VirtualCallSite> CallSites;
/// Whether all call sites represented by this CallSiteInfo, including those
/// in summaries, have been devirtualized. This starts off as true because a
/// default constructed CallSiteInfo represents no call sites.
bool AllCallSitesDevirted = true;
// These fields are used during the export phase of ThinLTO and reflect
// information collected from function summaries.
/// Whether any function summary contains an llvm.assume(llvm.type.test) for
/// this slot.
bool SummaryHasTypeTestAssumeUsers;
bool SummaryHasTypeTestAssumeUsers = false;
/// CFI-specific: a vector containing the list of function summaries that use
/// the llvm.type.checked.load intrinsic and therefore will require
@ -337,8 +342,22 @@ struct CallSiteInfo {
!SummaryTypeCheckedLoadUsers.empty();
}
/// As explained in the comment for SummaryTypeCheckedLoadUsers.
void markDevirt() { SummaryTypeCheckedLoadUsers.clear(); }
void markSummaryHasTypeTestAssumeUsers() {
SummaryHasTypeTestAssumeUsers = true;
AllCallSitesDevirted = false;
}
void addSummaryTypeCheckedLoadUser(FunctionSummary *FS) {
SummaryTypeCheckedLoadUsers.push_back(FS);
AllCallSitesDevirted = false;
}
void markDevirt() {
AllCallSitesDevirted = true;
// As explained in the comment for SummaryTypeCheckedLoadUsers.
SummaryTypeCheckedLoadUsers.clear();
}
};
// Call site information collected for a specific VTableSlot.
@ -373,7 +392,9 @@ CallSiteInfo &VTableSlotInfo::findCallSiteInfo(CallSite CS) {
void VTableSlotInfo::addCallSite(Value *VTable, CallSite CS,
unsigned *NumUnsafeUses) {
findCallSiteInfo(CS).CallSites.push_back({VTable, CS, NumUnsafeUses});
auto &CSI = findCallSiteInfo(CS);
CSI.AllCallSitesDevirted = false;
CSI.CallSites.push_back({VTable, CS, NumUnsafeUses});
}
struct DevirtModule {
@ -438,6 +459,12 @@ struct DevirtModule {
VTableSlotInfo &SlotInfo,
WholeProgramDevirtResolution *Res);
void applyICallBranchFunnel(VTableSlotInfo &SlotInfo, Constant *JT,
bool &IsExported);
void tryICallBranchFunnel(MutableArrayRef<VirtualCallTarget> TargetsForSlot,
VTableSlotInfo &SlotInfo,
WholeProgramDevirtResolution *Res, VTableSlot Slot);
bool tryEvaluateFunctionsWithArgs(
MutableArrayRef<VirtualCallTarget> TargetsForSlot,
ArrayRef<uint64_t> Args);
@ -471,6 +498,8 @@ struct DevirtModule {
StringRef Name, IntegerType *IntTy,
uint32_t Storage);
Constant *getMemberAddr(const TypeMemberInfo *M);
void applyUniqueRetValOpt(CallSiteInfo &CSInfo, StringRef FnName, bool IsOne,
Constant *UniqueMemberAddr);
bool tryUniqueRetValOpt(unsigned BitWidth,
@ -726,10 +755,9 @@ void DevirtModule::applySingleImplDevirt(VTableSlotInfo &SlotInfo,
if (VCallSite.NumUnsafeUses)
--*VCallSite.NumUnsafeUses;
}
if (CSInfo.isExported()) {
if (CSInfo.isExported())
IsExported = true;
CSInfo.markDevirt();
}
CSInfo.markDevirt();
};
Apply(SlotInfo.CSInfo);
for (auto &P : SlotInfo.ConstCSInfo)
@ -785,6 +813,134 @@ bool DevirtModule::trySingleImplDevirt(
return true;
}
void DevirtModule::tryICallBranchFunnel(
MutableArrayRef<VirtualCallTarget> TargetsForSlot, VTableSlotInfo &SlotInfo,
WholeProgramDevirtResolution *Res, VTableSlot Slot) {
Triple T(M.getTargetTriple());
if (T.getArch() != Triple::x86_64)
return;
const unsigned kBranchFunnelThreshold = 10;
if (TargetsForSlot.size() > kBranchFunnelThreshold)
return;
bool HasNonDevirt = !SlotInfo.CSInfo.AllCallSitesDevirted;
if (!HasNonDevirt)
for (auto &P : SlotInfo.ConstCSInfo)
if (!P.second.AllCallSitesDevirted) {
HasNonDevirt = true;
break;
}
if (!HasNonDevirt)
return;
FunctionType *FT =
FunctionType::get(Type::getVoidTy(M.getContext()), {Int8PtrTy}, true);
Function *JT;
if (isa<MDString>(Slot.TypeID)) {
JT = Function::Create(FT, Function::ExternalLinkage,
getGlobalName(Slot, {}, "branch_funnel"), &M);
JT->setVisibility(GlobalValue::HiddenVisibility);
} else {
JT = Function::Create(FT, Function::InternalLinkage, "branch_funnel", &M);
}
JT->addAttribute(1, Attribute::Nest);
std::vector<Value *> JTArgs;
JTArgs.push_back(JT->arg_begin());
for (auto &T : TargetsForSlot) {
JTArgs.push_back(getMemberAddr(T.TM));
JTArgs.push_back(T.Fn);
}
BasicBlock *BB = BasicBlock::Create(M.getContext(), "", JT, nullptr);
Constant *Intr =
Intrinsic::getDeclaration(&M, llvm::Intrinsic::icall_branch_funnel, {});
auto *CI = CallInst::Create(Intr, JTArgs, "", BB);
CI->setTailCallKind(CallInst::TCK_MustTail);
ReturnInst::Create(M.getContext(), nullptr, BB);
bool IsExported = false;
applyICallBranchFunnel(SlotInfo, JT, IsExported);
if (IsExported)
Res->TheKind = WholeProgramDevirtResolution::BranchFunnel;
}
void DevirtModule::applyICallBranchFunnel(VTableSlotInfo &SlotInfo,
Constant *JT, bool &IsExported) {
auto Apply = [&](CallSiteInfo &CSInfo) {
if (CSInfo.isExported())
IsExported = true;
if (CSInfo.AllCallSitesDevirted)
return;
for (auto &&VCallSite : CSInfo.CallSites) {
CallSite CS = VCallSite.CS;
// Jump tables are only profitable if the retpoline mitigation is enabled.
Attribute FSAttr = CS.getCaller()->getFnAttribute("target-features");
if (FSAttr.hasAttribute(Attribute::None) ||
!FSAttr.getValueAsString().contains("+retpoline"))
continue;
if (RemarksEnabled)
VCallSite.emitRemark("branch-funnel", JT->getName(), OREGetter);
// Pass the address of the vtable in the nest register, which is r10 on
// x86_64.
std::vector<Type *> NewArgs;
NewArgs.push_back(Int8PtrTy);
for (Type *T : CS.getFunctionType()->params())
NewArgs.push_back(T);
PointerType *NewFT = PointerType::getUnqual(
FunctionType::get(CS.getFunctionType()->getReturnType(), NewArgs,
CS.getFunctionType()->isVarArg()));
IRBuilder<> IRB(CS.getInstruction());
std::vector<Value *> Args;
Args.push_back(IRB.CreateBitCast(VCallSite.VTable, Int8PtrTy));
for (unsigned I = 0; I != CS.getNumArgOperands(); ++I)
Args.push_back(CS.getArgOperand(I));
CallSite NewCS;
if (CS.isCall())
NewCS = IRB.CreateCall(IRB.CreateBitCast(JT, NewFT), Args);
else
NewCS = IRB.CreateInvoke(
IRB.CreateBitCast(JT, NewFT),
cast<InvokeInst>(CS.getInstruction())->getNormalDest(),
cast<InvokeInst>(CS.getInstruction())->getUnwindDest(), Args);
NewCS.setCallingConv(CS.getCallingConv());
AttributeList Attrs = CS.getAttributes();
std::vector<AttributeSet> NewArgAttrs;
NewArgAttrs.push_back(AttributeSet::get(
M.getContext(), ArrayRef<Attribute>{Attribute::get(
M.getContext(), Attribute::Nest)}));
for (unsigned I = 0; I + 2 < Attrs.getNumAttrSets(); ++I)
NewArgAttrs.push_back(Attrs.getParamAttributes(I));
NewCS.setAttributes(
AttributeList::get(M.getContext(), Attrs.getFnAttributes(),
Attrs.getRetAttributes(), NewArgAttrs));
CS->replaceAllUsesWith(NewCS.getInstruction());
CS->eraseFromParent();
// This use is no longer unsafe.
if (VCallSite.NumUnsafeUses)
--*VCallSite.NumUnsafeUses;
}
// Don't mark as devirtualized because there may be callers compiled without
// retpoline mitigation, which would mean that they are lowered to
// llvm.type.test and therefore require an llvm.type.test resolution for the
// type identifier.
};
Apply(SlotInfo.CSInfo);
for (auto &P : SlotInfo.ConstCSInfo)
Apply(P.second);
}
bool DevirtModule::tryEvaluateFunctionsWithArgs(
MutableArrayRef<VirtualCallTarget> TargetsForSlot,
ArrayRef<uint64_t> Args) {
@ -937,6 +1093,12 @@ void DevirtModule::applyUniqueRetValOpt(CallSiteInfo &CSInfo, StringRef FnName,
CSInfo.markDevirt();
}
Constant *DevirtModule::getMemberAddr(const TypeMemberInfo *M) {
Constant *C = ConstantExpr::getBitCast(M->Bits->GV, Int8PtrTy);
return ConstantExpr::getGetElementPtr(Int8Ty, C,
ConstantInt::get(Int64Ty, M->Offset));
}
bool DevirtModule::tryUniqueRetValOpt(
unsigned BitWidth, MutableArrayRef<VirtualCallTarget> TargetsForSlot,
CallSiteInfo &CSInfo, WholeProgramDevirtResolution::ByArg *Res,
@ -956,12 +1118,7 @@ bool DevirtModule::tryUniqueRetValOpt(
// checked for a uniform return value in tryUniformRetValOpt.
assert(UniqueMember);
Constant *UniqueMemberAddr =
ConstantExpr::getBitCast(UniqueMember->Bits->GV, Int8PtrTy);
UniqueMemberAddr = ConstantExpr::getGetElementPtr(
Int8Ty, UniqueMemberAddr,
ConstantInt::get(Int64Ty, UniqueMember->Offset));
Constant *UniqueMemberAddr = getMemberAddr(UniqueMember);
if (CSInfo.isExported()) {
Res->TheKind = WholeProgramDevirtResolution::ByArg::UniqueRetVal;
Res->Info = IsOne;
@ -1348,6 +1505,14 @@ void DevirtModule::importResolution(VTableSlot Slot, VTableSlotInfo &SlotInfo) {
break;
}
}
if (Res.TheKind == WholeProgramDevirtResolution::BranchFunnel) {
auto *JT = M.getOrInsertFunction(getGlobalName(Slot, {}, "branch_funnel"),
Type::getVoidTy(M.getContext()));
bool IsExported = false;
applyICallBranchFunnel(SlotInfo, JT, IsExported);
assert(!IsExported);
}
}
void DevirtModule::removeRedundantTypeTests() {
@ -1417,14 +1582,13 @@ bool DevirtModule::run() {
// FIXME: Only add live functions.
for (FunctionSummary::VFuncId VF : FS->type_test_assume_vcalls()) {
for (Metadata *MD : MetadataByGUID[VF.GUID]) {
CallSlots[{MD, VF.Offset}].CSInfo.SummaryHasTypeTestAssumeUsers =
true;
CallSlots[{MD, VF.Offset}]
.CSInfo.markSummaryHasTypeTestAssumeUsers();
}
}
for (FunctionSummary::VFuncId VF : FS->type_checked_load_vcalls()) {
for (Metadata *MD : MetadataByGUID[VF.GUID]) {
CallSlots[{MD, VF.Offset}]
.CSInfo.SummaryTypeCheckedLoadUsers.push_back(FS);
CallSlots[{MD, VF.Offset}].CSInfo.addSummaryTypeCheckedLoadUser(FS);
}
}
for (const FunctionSummary::ConstVCall &VC :
@ -1432,7 +1596,7 @@ bool DevirtModule::run() {
for (Metadata *MD : MetadataByGUID[VC.VFunc.GUID]) {
CallSlots[{MD, VC.VFunc.Offset}]
.ConstCSInfo[VC.Args]
.SummaryHasTypeTestAssumeUsers = true;
.markSummaryHasTypeTestAssumeUsers();
}
}
for (const FunctionSummary::ConstVCall &VC :
@ -1440,7 +1604,7 @@ bool DevirtModule::run() {
for (Metadata *MD : MetadataByGUID[VC.VFunc.GUID]) {
CallSlots[{MD, VC.VFunc.Offset}]
.ConstCSInfo[VC.Args]
.SummaryTypeCheckedLoadUsers.push_back(FS);
.addSummaryTypeCheckedLoadUser(FS);
}
}
}
@ -1464,9 +1628,12 @@ bool DevirtModule::run() {
cast<MDString>(S.first.TypeID)->getString())
.WPDRes[S.first.ByteOffset];
if (!trySingleImplDevirt(TargetsForSlot, S.second, Res) &&
tryVirtualConstProp(TargetsForSlot, S.second, Res, S.first))
DidVirtualConstProp = true;
if (!trySingleImplDevirt(TargetsForSlot, S.second, Res)) {
DidVirtualConstProp |=
tryVirtualConstProp(TargetsForSlot, S.second, Res, S.first);
tryICallBranchFunnel(TargetsForSlot, S.second, Res, S.first);
}
// Collect functions devirtualized at least for one call site for stats.
if (RemarksEnabled)

170
test/CodeGen/X86/icall-branch-funnel.ll Normal file
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@ -0,0 +1,170 @@
; RUN: llc -mtriple=x86_64-unknown-linux < %s | FileCheck %s
@g = external global i8
declare void @f0()
declare void @f1()
declare void @f2()
declare void @f3()
declare void @f4()
declare void @f5()
declare void @f6()
declare void @f7()
declare void @f8()
declare void @f9()
declare void @llvm.icall.branch.funnel(...)
define void @jt2(i8* nest, ...) {
; CHECK: jt2:
; CHECK: leaq g+1(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB0_1
; CHECK-NEXT: #
; CHECK-NEXT: jmp f0
; CHECK-NEXT: .LBB0_1:
; CHECK-NEXT: jmp f1
musttail call void (...) @llvm.icall.branch.funnel(
i8* %0,
i8* getelementptr (i8, i8* @g, i64 0), void ()* @f0,
i8* getelementptr (i8, i8* @g, i64 1), void ()* @f1,
...
)
ret void
}
define void @jt3(i8* nest, ...) {
; CHECK: jt3:
; CHECK: leaq g+1(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB1_1
; CHECK-NEXT: #
; CHECK-NEXT: jmp f0
; CHECK-NEXT: .LBB1_1:
; CHECK-NEXT: jne .LBB1_2
; CHECK-NEXT: #
; CHECK-NEXT: jmp f1
; CHECK-NEXT: .LBB1_2:
; CHECK-NEXT: jmp f2
musttail call void (...) @llvm.icall.branch.funnel(
i8* %0,
i8* getelementptr (i8, i8* @g, i64 0), void ()* @f0,
i8* getelementptr (i8, i8* @g, i64 2), void ()* @f2,
i8* getelementptr (i8, i8* @g, i64 1), void ()* @f1,
...
)
ret void
}
define void @jt7(i8* nest, ...) {
; CHECK: jt7:
; CHECK: leaq g+3(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB2_1
; CHECK-NEXT: #
; CHECK-NEXT: leaq g+1(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB2_6
; CHECK-NEXT: #
; CHECK-NEXT: jmp f0
; CHECK-NEXT: .LBB2_1:
; CHECK-NEXT: jne .LBB2_2
; CHECK-NEXT: #
; CHECK-NEXT: jmp f3
; CHECK-NEXT: .LBB2_6:
; CHECK-NEXT: jne .LBB2_7
; CHECK-NEXT: #
; CHECK-NEXT: jmp f1
; CHECK-NEXT: .LBB2_2:
; CHECK-NEXT: leaq g+5(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB2_3
; CHECK-NEXT: #
; CHECK-NEXT: jmp f4
; CHECK-NEXT: .LBB2_7:
; CHECK-NEXT: jmp f2
; CHECK-NEXT: .LBB2_3:
; CHECK-NEXT: jne .LBB2_4
; CHECK-NEXT: #
; CHECK-NEXT: jmp f5
; CHECK-NEXT: .LBB2_4:
; CHECK-NEXT: jmp f6
musttail call void (...) @llvm.icall.branch.funnel(
i8* %0,
i8* getelementptr (i8, i8* @g, i64 0), void ()* @f0,
i8* getelementptr (i8, i8* @g, i64 1), void ()* @f1,
i8* getelementptr (i8, i8* @g, i64 2), void ()* @f2,
i8* getelementptr (i8, i8* @g, i64 3), void ()* @f3,
i8* getelementptr (i8, i8* @g, i64 4), void ()* @f4,
i8* getelementptr (i8, i8* @g, i64 5), void ()* @f5,
i8* getelementptr (i8, i8* @g, i64 6), void ()* @f6,
...
)
ret void
}
define void @jt10(i8* nest, ...) {
; CHECK: jt10:
; CHECK: leaq g+5(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB3_1
; CHECK-NEXT: #
; CHECK-NEXT: leaq g+1(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB3_7
; CHECK-NEXT: #
; CHECK-NEXT: jmp f0
; CHECK-NEXT: .LBB3_1:
; CHECK-NEXT: jne .LBB3_2
; CHECK-NEXT: #
; CHECK-NEXT: jmp f5
; CHECK-NEXT: .LBB3_7:
; CHECK-NEXT: jne .LBB3_8
; CHECK-NEXT: #
; CHECK-NEXT: jmp f1
; CHECK-NEXT: .LBB3_2:
; CHECK-NEXT: leaq g+7(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB3_3
; CHECK-NEXT: #
; CHECK-NEXT: jmp f6
; CHECK-NEXT: .LBB3_8:
; CHECK-NEXT: leaq g+3(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB3_9
; CHECK-NEXT: #
; CHECK-NEXT: jmp f2
; CHECK-NEXT: .LBB3_3:
; CHECK-NEXT: jne .LBB3_4
; CHECK-NEXT: #
; CHECK-NEXT: jmp f7
; CHECK-NEXT: .LBB3_9:
; CHECK-NEXT: jne .LBB3_10
; CHECK-NEXT: #
; CHECK-NEXT: jmp f3
; CHECK-NEXT: .LBB3_4:
; CHECK-NEXT: leaq g+9(%rip), %r11
; CHECK-NEXT: cmpq %r11, %r10
; CHECK-NEXT: jae .LBB3_5
; CHECK-NEXT: #
; CHECK-NEXT: jmp f8
; CHECK-NEXT: .LBB3_10:
; CHECK-NEXT: jmp f4
; CHECK-NEXT: .LBB3_5:
; CHECK-NEXT: jmp f9
musttail call void (...) @llvm.icall.branch.funnel(
i8* %0,
i8* getelementptr (i8, i8* @g, i64 0), void ()* @f0,
i8* getelementptr (i8, i8* @g, i64 1), void ()* @f1,
i8* getelementptr (i8, i8* @g, i64 2), void ()* @f2,
i8* getelementptr (i8, i8* @g, i64 3), void ()* @f3,
i8* getelementptr (i8, i8* @g, i64 4), void ()* @f4,
i8* getelementptr (i8, i8* @g, i64 5), void ()* @f5,
i8* getelementptr (i8, i8* @g, i64 6), void ()* @f6,
i8* getelementptr (i8, i8* @g, i64 7), void ()* @f7,
i8* getelementptr (i8, i8* @g, i64 8), void ()* @f8,
i8* getelementptr (i8, i8* @g, i64 9), void ()* @f9,
...
)
ret void
}

46
test/Transforms/LowerTypeTests/icall-branch-funnel.ll Normal file
View File

@ -0,0 +1,46 @@
; RUN: opt -S -lowertypetests < %s | FileCheck %s
target datalayout = "e-p:64:64"
target triple = "x86_64-unknown-linux"
; CHECK: @0 = private constant { i32, [0 x i8], i32 } { i32 1, [0 x i8] zeroinitializer, i32 2 }
; CHECK: @f1 = alias void (), void ()* @.cfi.jumptable
; CHECK: @f2 = alias void (), bitcast ([8 x i8]* getelementptr inbounds ([2 x [8 x i8]], [2 x [8 x i8]]* bitcast (void ()* @.cfi.jumptable to [2 x [8 x i8]]*), i64 0, i64 1) to void ()*)
; CHECK: @g1 = alias i32, getelementptr inbounds ({ i32, [0 x i8], i32 }, { i32, [0 x i8], i32 }* @0, i32 0, i32 0)
; CHECK: @g2 = alias i32, getelementptr inbounds ({ i32, [0 x i8], i32 }, { i32, [0 x i8], i32 }* @0, i32 0, i32 2)
@g1 = constant i32 1
@g2 = constant i32 2
define void @f1() {
ret void
}
define void @f2() {
ret void
}
declare void @g1f()
declare void @g2f()
define void @jt2(i8* nest, ...) {
musttail call void (...) @llvm.icall.branch.funnel(
i8* %0,
i32* @g1, void ()* @g1f,
i32* @g2, void ()* @g2f,
...
)
ret void
}
define void @jt3(i8* nest, ...) {
musttail call void (...) @llvm.icall.branch.funnel(
i8* %0,
void ()* @f1, void ()* @f1,
void ()* @f2, void ()* @f2,
...
)
ret void
}
declare void @llvm.icall.branch.funnel(...)

11
test/Transforms/WholeProgramDevirt/Inputs/import-branch-funnel.yaml Normal file
View File

@ -0,0 +1,11 @@
---
TypeIdMap:
typeid1:
WPDRes:
0:
Kind: BranchFunnel
typeid2:
WPDRes:
8:
Kind: BranchFunnel
...

23
test/Transforms/WholeProgramDevirt/Inputs/import-vcp-branch-funnel.yaml Normal file
View File

@ -0,0 +1,23 @@
---
TypeIdMap:
typeid1:
WPDRes:
0:
Kind: BranchFunnel
ResByArg:
1:
Kind: VirtualConstProp
Info: 0
Byte: 42
Bit: 0
typeid2:
WPDRes:
8:
Kind: BranchFunnel
ResByArg:
3:
Kind: VirtualConstProp
Info: 0
Byte: 43
Bit: 128
...

155
test/Transforms/WholeProgramDevirt/branch-funnel.ll Normal file
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@ -0,0 +1,155 @@
; RUN: opt -S -wholeprogramdevirt %s | FileCheck --check-prefixes=CHECK,RETP %s
; RUN: sed -e 's,+retpoline,-retpoline,g' %s | opt -S -wholeprogramdevirt | FileCheck --check-prefixes=CHECK,NORETP %s
; RUN: opt -wholeprogramdevirt -wholeprogramdevirt-summary-action=export -wholeprogramdevirt-read-summary=%S/Inputs/export.yaml -wholeprogramdevirt-write-summary=%t -S -o - %s | FileCheck --check-prefixes=CHECK,RETP %s
; RUN: FileCheck --check-prefix=SUMMARY %s < %t
; SUMMARY: TypeIdMap:
; SUMMARY-NEXT: typeid1:
; SUMMARY-NEXT: TTRes:
; SUMMARY-NEXT: Kind: Unsat
; SUMMARY-NEXT: SizeM1BitWidth: 0
; SUMMARY-NEXT: AlignLog2: 0
; SUMMARY-NEXT: SizeM1: 0
; SUMMARY-NEXT: BitMask: 0
; SUMMARY-NEXT: InlineBits: 0
; SUMMARY-NEXT: WPDRes:
; SUMMARY-NEXT: 0:
; SUMMARY-NEXT: Kind: BranchFunnel
; SUMMARY-NEXT: SingleImplName: ''
; SUMMARY-NEXT: ResByArg:
; SUMMARY-NEXT: typeid2:
; SUMMARY-NEXT: TTRes:
; SUMMARY-NEXT: Kind: Unsat
; SUMMARY-NEXT: SizeM1BitWidth: 0
; SUMMARY-NEXT: AlignLog2: 0
; SUMMARY-NEXT: SizeM1: 0
; SUMMARY-NEXT: BitMask: 0
; SUMMARY-NEXT: InlineBits: 0
; SUMMARY-NEXT: WPDRes:
; SUMMARY-NEXT: 0:
; SUMMARY-NEXT: Kind: Indir
; SUMMARY-NEXT: SingleImplName: ''
; SUMMARY-NEXT: ResByArg:
; SUMMARY-NEXT: typeid3:
; SUMMARY-NEXT: TTRes:
; SUMMARY-NEXT: Kind: Unsat
; SUMMARY-NEXT: SizeM1BitWidth: 0
; SUMMARY-NEXT: AlignLog2: 0
; SUMMARY-NEXT: SizeM1: 0
; SUMMARY-NEXT: BitMask: 0
; SUMMARY-NEXT: InlineBits: 0
; SUMMARY-NEXT: WPDRes:
; SUMMARY-NEXT: 0:
; SUMMARY-NEXT: Kind: BranchFunnel
; SUMMARY-NEXT: SingleImplName: ''
; SUMMARY-NEXT: ResByArg:
target datalayout = "e-p:64:64"
target triple = "x86_64-unknown-linux-gnu"
@vt1_1 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf1_1 to i8*)], !type !0
@vt1_2 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf1_2 to i8*)], !type !0
declare i32 @vf1_1(i8* %this, i32 %arg)
declare i32 @vf1_2(i8* %this, i32 %arg)
@vt2_1 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_1 to i8*)], !type !1
@vt2_2 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_2 to i8*)], !type !1
@vt2_3 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_3 to i8*)], !type !1
@vt2_4 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_4 to i8*)], !type !1
@vt2_5 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_5 to i8*)], !type !1
@vt2_6 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_6 to i8*)], !type !1
@vt2_7 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_7 to i8*)], !type !1
@vt2_8 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_8 to i8*)], !type !1
@vt2_9 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_9 to i8*)], !type !1
@vt2_10 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_10 to i8*)], !type !1
@vt2_11 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf2_11 to i8*)], !type !1
declare i32 @vf2_1(i8* %this, i32 %arg)
declare i32 @vf2_2(i8* %this, i32 %arg)
declare i32 @vf2_3(i8* %this, i32 %arg)
declare i32 @vf2_4(i8* %this, i32 %arg)
declare i32 @vf2_5(i8* %this, i32 %arg)
declare i32 @vf2_6(i8* %this, i32 %arg)
declare i32 @vf2_7(i8* %this, i32 %arg)
declare i32 @vf2_8(i8* %this, i32 %arg)
declare i32 @vf2_9(i8* %this, i32 %arg)
declare i32 @vf2_10(i8* %this, i32 %arg)
declare i32 @vf2_11(i8* %this, i32 %arg)
@vt3_1 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf3_1 to i8*)], !type !2
@vt3_2 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf3_2 to i8*)], !type !2
declare i32 @vf3_1(i8* %this, i32 %arg)
declare i32 @vf3_2(i8* %this, i32 %arg)
@vt4_1 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf4_1 to i8*)], !type !3
@vt4_2 = constant [1 x i8*] [i8* bitcast (i32 (i8*, i32)* @vf4_2 to i8*)], !type !3
declare i32 @vf4_1(i8* %this, i32 %arg)
declare i32 @vf4_2(i8* %this, i32 %arg)
; CHECK: define i32 @fn1
define i32 @fn1(i8* %obj) #0 {
%vtableptr = bitcast i8* %obj to [1 x i8*]**
%vtable = load [1 x i8*]*, [1 x i8*]** %vtableptr
%vtablei8 = bitcast [1 x i8*]* %vtable to i8*
%p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid1")
call void @llvm.assume(i1 %p)
%fptrptr = getelementptr [1 x i8*], [1 x i8*]* %vtable, i32 0, i32 0
%fptr = load i8*, i8** %fptrptr
%fptr_casted = bitcast i8* %fptr to i32 (i8*, i32)*
; RETP: {{.*}} = bitcast {{.*}} to i8*
; RETP: [[VT1:%.*]] = bitcast {{.*}} to i8*
; RETP: call i32 bitcast (void (i8*, ...)* @__typeid_typeid1_0_branch_funnel to i32 (i8*, i8*, i32)*)(i8* nest [[VT1]], i8* %obj, i32 1)
%result = call i32 %fptr_casted(i8* %obj, i32 1)
; NORETP: call i32 %
ret i32 %result
}
; CHECK: define i32 @fn2
define i32 @fn2(i8* %obj) #0 {
%vtableptr = bitcast i8* %obj to [1 x i8*]**
%vtable = load [1 x i8*]*, [1 x i8*]** %vtableptr
%vtablei8 = bitcast [1 x i8*]* %vtable to i8*
%p = call i1 @llvm.type.test(i8* %vtablei8, metadata !"typeid2")
call void @llvm.assume(i1 %p)
%fptrptr = getelementptr [1 x i8*], [1 x i8*]* %vtable, i32 0, i32 0
%fptr = load i8*, i8** %fptrptr
%fptr_casted = bitcast i8* %fptr to i32 (i8*, i32)*
; CHECK: call i32 %
%result = call i32 %fptr_casted(i8* %obj, i32 1)
ret i32 %result
}
; CHECK: define i32 @fn3
define i32 @fn3(i8* %obj) #0 {
%vtableptr = bitcast i8* %obj to [1 x i8*]**
%vtable = load [1 x i8*]*, [1 x i8*]** %vtableptr
%vtablei8 = bitcast [1 x i8*]* %vtable to i8*
%p = call i1 @llvm.type.test(i8* %vtablei8, metadata !4)
call void @llvm.assume(i1 %p)
%fptrptr = getelementptr [1 x i8*], [1 x i8*]* %vtable, i32 0, i32 0
%fptr = load i8*, i8** %fptrptr
%fptr_casted = bitcast i8* %fptr to i32 (i8*, i32)*
; RETP: call i32 bitcast (void (i8*, ...)* @branch_funnel to
; NORETP: call i32 %
%result = call i32 %fptr_casted(i8* %obj, i32 1)
ret i32 %result
}
; CHECK: define internal void @branch_funnel(i8* nest, ...)
; CHECK: define hidden void @__typeid_typeid1_0_branch_funnel(i8* nest, ...)
; CHECK-NEXT: call void (...) @llvm.icall.branch.funnel(i8* %0, i8* bitcast ([1 x i8*]* @vt1_1 to i8*), i32 (i8*, i32)* @vf1_1, i8* bitcast ([1 x i8*]* @vt1_2 to i8*), i32 (i8*, i32)* @vf1_2, ...)
declare i1 @llvm.type.test(i8*, metadata)
declare void @llvm.assume(i1)
!0 = !{i32 0, !"typeid1"}
!1 = !{i32 0, !"typeid2"}
!2 = !{i32 0, !"typeid3"}
!3 = !{i32 0, !4}
!4 = distinct !{}
attributes #0 = { "target-features"="+retpoline" }

32
test/Transforms/WholeProgramDevirt/import.ll
View File

@ -1,10 +1,12 @@
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-single-impl.yaml < %s | FileCheck --check-prefixes=CHECK,SINGLE-IMPL %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-uniform-ret-val.yaml < %s | FileCheck --check-prefixes=CHECK,UNIFORM-RET-VAL %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-unique-ret-val0.yaml < %s | FileCheck --check-prefixes=CHECK,UNIQUE-RET-VAL0 %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-unique-ret-val1.yaml < %s | FileCheck --check-prefixes=CHECK,UNIQUE-RET-VAL1 %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-vcp.yaml < %s | FileCheck --check-prefixes=CHECK,VCP,VCP-X86,VCP64 %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-uniform-ret-val.yaml < %s | FileCheck --check-prefixes=CHECK,INDIR,UNIFORM-RET-VAL %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-unique-ret-val0.yaml < %s | FileCheck --check-prefixes=CHECK,INDIR,UNIQUE-RET-VAL0 %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-unique-ret-val1.yaml < %s | FileCheck --check-prefixes=CHECK,INDIR,UNIQUE-RET-VAL1 %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-vcp.yaml < %s | FileCheck --check-prefixes=CHECK,VCP,VCP-X86,VCP64,INDIR %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-vcp.yaml -mtriple=i686-unknown-linux -data-layout=e-p:32:32 < %s | FileCheck --check-prefixes=CHECK,VCP,VCP-X86,VCP32 %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-vcp.yaml -mtriple=armv7-unknown-linux -data-layout=e-p:32:32 < %s | FileCheck --check-prefixes=CHECK,VCP,VCP-ARM %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-vcp-branch-funnel.yaml < %s | FileCheck --check-prefixes=CHECK,VCP,VCP-X86,VCP64,BRANCH-FUNNEL %s
; RUN: opt -S -wholeprogramdevirt -wholeprogramdevirt-summary-action=import -wholeprogramdevirt-read-summary=%S/Inputs/import-branch-funnel.yaml < %s | FileCheck --check-prefixes=CHECK,BRANCH-FUNNEL,BRANCH-FUNNEL-NOVCP %s
target datalayout = "e-p:64:64"
target triple = "x86_64-unknown-linux-gnu"
@ -18,7 +20,7 @@ target triple = "x86_64-unknown-linux-gnu"
; constant propagation.
; CHECK: define i32 @call1
define i32 @call1(i8* %obj) {
define i32 @call1(i8* %obj) #0 {
%vtableptr = bitcast i8* %obj to [3 x i8*]**
%vtable = load [3 x i8*]*, [3 x i8*]** %vtableptr
%vtablei8 = bitcast [3 x i8*]* %vtable to i8*
@ -27,16 +29,18 @@ define i32 @call1(i8* %obj) {
%fptrptr = getelementptr [3 x i8*], [3 x i8*]* %vtable, i32 0, i32 0
%fptr = load i8*, i8** %fptrptr
%fptr_casted = bitcast i8* %fptr to i32 (i8*, i32)*
; CHECK: {{.*}} = bitcast {{.*}} to i8*
; VCP: [[VT1:%.*]] = bitcast {{.*}} to i8*
; SINGLE-IMPL: call i32 bitcast (void ()* @singleimpl1 to i32 (i8*, i32)*)
%result = call i32 %fptr_casted(i8* %obj, i32 1)
; UNIFORM-RET-VAL: ret i32 42
; VCP: {{.*}} = bitcast {{.*}} to i8*
; VCP: [[VT1:%.*]] = bitcast {{.*}} to i8*
; VCP-X86: [[GEP1:%.*]] = getelementptr i8, i8* [[VT1]], i32 ptrtoint (i8* @__typeid_typeid1_0_1_byte to i32)
; VCP-ARM: [[GEP1:%.*]] = getelementptr i8, i8* [[VT1]], i32 42
; VCP: [[BC1:%.*]] = bitcast i8* [[GEP1]] to i32*
; VCP: [[LOAD1:%.*]] = load i32, i32* [[BC1]]
; VCP: ret i32 [[LOAD1]]
; BRANCH-FUNNEL-NOVCP: [[VT1:%.*]] = bitcast {{.*}} to i8*
; BRANCH-FUNNEL-NOVCP: call i32 bitcast (void ()* @__typeid_typeid1_0_branch_funnel to i32 (i8*, i8*, i32)*)(i8* nest [[VT1]], i8* %obj, i32 1)
ret i32 %result
}
@ -44,7 +48,8 @@ define i32 @call1(i8* %obj) {
; constant propagation.
; CHECK: define i1 @call2
define i1 @call2(i8* %obj) {
define i1 @call2(i8* %obj) #0 {
; BRANCH-FUNNEL: [[VT1:%.*]] = bitcast {{.*}} to i8*
%vtableptr = bitcast i8* %obj to [1 x i8*]**
%vtable = load [1 x i8*]*, [1 x i8*]** %vtableptr
%vtablei8 = bitcast [1 x i8*]* %vtable to i8*
@ -57,9 +62,8 @@ define i1 @call2(i8* %obj) {
cont:
%fptr_casted = bitcast i8* %fptr to i1 (i8*, i32)*
; SINGLE-IMPL: call i1 bitcast (void ()* @singleimpl2 to i1 (i8*, i32)*)
; UNIFORM-RET-VAL: call i1 %
; UNIQUE-RET-VAL0: call i1 %
; UNIQUE-RET-VAL1: call i1 %
; INDIR: call i1 %
; BRANCH-FUNNEL: call i1 bitcast (void ()* @__typeid_typeid2_8_branch_funnel to i1 (i8*, i8*, i32)*)(i8* nest [[VT1]], i8* %obj, i32 undef)
%result = call i1 %fptr_casted(i8* %obj, i32 undef)
ret i1 %result
@ -69,7 +73,7 @@ trap:
}
; CHECK: define i1 @call3
define i1 @call3(i8* %obj) {
define i1 @call3(i8* %obj) #0 {
%vtableptr = bitcast i8* %obj to [1 x i8*]**
%vtable = load [1 x i8*]*, [1 x i8*]** %vtableptr
%vtablei8 = bitcast [1 x i8*]* %vtable to i8*
@ -91,6 +95,8 @@ cont:
; VCP-ARM: [[AND2:%.*]] = and i8 [[LOAD2]], -128
; VCP: [[ICMP2:%.*]] = icmp ne i8 [[AND2]], 0
; VCP: ret i1 [[ICMP2]]
; BRANCH-FUNNEL-NOVCP: [[VT2:%.*]] = bitcast {{.*}} to i8*
; BRANCH-FUNNEL-NOVCP: call i1 bitcast (void ()* @__typeid_typeid2_8_branch_funnel to i1 (i8*, i8*, i32)*)(i8* nest [[VT2]], i8* %obj, i32 3)
ret i1 %result
trap:
@ -111,3 +117,5 @@ declare void @llvm.assume(i1)
declare void @llvm.trap()
declare {i8*, i1} @llvm.type.checked.load(i8*, i32, metadata)
declare i1 @llvm.type.test(i8*, metadata)
attributes #0 = { "target-features"="+retpoline" }