void buildTypeIdentifierMap(
std::vector<VTableBits> &Bits,
DenseMap<Metadata *, std::set<TypeMemberInfo>> &TypeIdMap);
+ Constant *getValueAtOffset(Constant *I, uint64_t Offset);
bool
tryFindVirtualCallTargets(std::vector<VirtualCallTarget> &TargetsForSlot,
const std::set<TypeMemberInfo> &TypeMemberInfos,
}
}
+Constant *DevirtModule::getValueAtOffset(Constant *I, uint64_t Offset) {
+ const DataLayout &DL = M.getDataLayout();
+ unsigned Op;
+
+ if (auto *C = dyn_cast<ConstantStruct>(I)) {
+ const StructLayout *SL = DL.getStructLayout(C->getType());
+
+ if (Offset >= SL->getSizeInBytes())
+ return nullptr;
+
+ Op = SL->getElementContainingOffset(Offset);
+
+ if (Offset != SL->getElementOffset(Op))
+ return nullptr;
+
+ } else if (auto *C = dyn_cast<ConstantArray>(I)) {
+ ArrayType *VTableTy = C->getType();
+ uint64_t ElemSize = DL.getTypeAllocSize(VTableTy->getElementType());
+
+ if (Offset % ElemSize != 0)
+ return nullptr;
+
+ Op = Offset / ElemSize;
+
+ if (Op >= C->getNumOperands())
+ return nullptr;
+ } else
+ return nullptr;
+
+ return cast<Constant>(I->getOperand(Op));
+}
+
bool DevirtModule::tryFindVirtualCallTargets(
std::vector<VirtualCallTarget> &TargetsForSlot,
const std::set<TypeMemberInfo> &TypeMemberInfos, uint64_t ByteOffset) {
if (!TM.Bits->GV->isConstant())
return false;
- auto Init = dyn_cast<ConstantArray>(TM.Bits->GV->getInitializer());
- if (!Init)
- return false;
- ArrayType *VTableTy = Init->getType();
-
- uint64_t ElemSize =
- M.getDataLayout().getTypeAllocSize(VTableTy->getElementType());
- uint64_t GlobalSlotOffset = TM.Offset + ByteOffset;
- if (GlobalSlotOffset % ElemSize != 0)
- return false;
+ Constant *I = TM.Bits->GV->getInitializer();
+ Value *V = getValueAtOffset(I, TM.Offset + ByteOffset);
- unsigned Op = GlobalSlotOffset / ElemSize;
- if (Op >= Init->getNumOperands())
+ if (!V)
return false;
- auto Fn = dyn_cast<Function>(Init->getOperand(Op)->stripPointerCasts());
+ auto Fn = dyn_cast<Function>(V->stripPointerCasts());
if (!Fn)
return false;
--- /dev/null
+; RUN: opt -S -wholeprogramdevirt %s | FileCheck %s
+
+target datalayout = "e-p:64:64"
+target triple = "x86_64-unknown-linux-gnu"
+
+%vtTy = type { void (i8*)* }
+
+@vt = constant %vtTy { void (i8*)* @vf }, !type !0
+
+define void @vf(i8* %this) {
+ ret void
+}
+
+; CHECK: define void @call
+define void @call(i8* %obj) {
+ %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 !"typeid")
+ 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 void (i8*)*
+ ; CHECK: call void @vf(
+ call void %fptr_casted(i8* %obj)
+ ret void
+}
+
+; CHECK: define void @call_oob
+define void @call_oob(i8* %obj) {
+ %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 !"typeid")
+ call void @llvm.assume(i1 %p)
+ %fptrptr = getelementptr [1 x i8*], [1 x i8*]* %vtable, i32 0, i32 4
+ %fptr = load i8*, i8** %fptrptr
+ %fptr_casted = bitcast i8* %fptr to void (i8*)*
+ ; CHECK: call void %
+ call void %fptr_casted(i8* %obj)
+ ret void
+}
+
+; CHECK: define void @call_unaligned
+define void @call_unaligned(i8* %obj) {
+ %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 !"typeid")
+ call void @llvm.assume(i1 %p)
+ %fptrptr = getelementptr i8, i8* %vtablei8, i32 1
+ %fptrptr_casted = bitcast i8* %fptrptr to i8**
+ %fptr = load i8*, i8** %fptrptr_casted
+ %fptr_casted = bitcast i8* %fptr to void (i8*)*
+ ; CHECK: call void %
+ call void %fptr_casted(i8* %obj)
+ ret void
+}
+
+declare i1 @llvm.type.test(i8*, metadata)
+declare void @llvm.assume(i1)
+
+!0 = !{i32 0, !"typeid"}