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-rw-r--r--lib/Analysis/TypeMetadataUtils.cpp32
1 files changed, 32 insertions, 0 deletions
diff --git a/lib/Analysis/TypeMetadataUtils.cpp b/lib/Analysis/TypeMetadataUtils.cpp
index 9311dfbc6eba..072d291f3f93 100644
--- a/lib/Analysis/TypeMetadataUtils.cpp
+++ b/lib/Analysis/TypeMetadataUtils.cpp
@@ -127,3 +127,35 @@ 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;
+}