Improve debug info generated with enabled AddressSanitizer.
When ASan replaces <alloca instruction> with
<offset into a common large alloca>, it should also patch
llvm.dbg.declare calls and replace debug info descriptors to mark
that we've replaced alloca with a value that stores an address
of the user variable, not the user variable itself.
See PR11818 for more context.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169984 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index 0e56817..58d973a 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -928,3 +928,38 @@
return 0;
}
+
+bool llvm::replaceDbgDeclareForAlloca(AllocaInst *AI, Value *NewAllocaAddress,
+ DIBuilder &Builder) {
+ DbgDeclareInst *DDI = FindAllocaDbgDeclare(AI);
+ if (!DDI)
+ return false;
+ DIVariable DIVar(DDI->getVariable());
+ if (!DIVar.Verify())
+ return false;
+
+ // Create a copy of the original DIDescriptor for user variable, appending
+ // "deref" operation to a list of address elements, as new llvm.dbg.declare
+ // will take a value storing address of the memory for variable, not
+ // alloca itself.
+ Type *Int64Ty = Type::getInt64Ty(AI->getContext());
+ SmallVector<Value*, 4> NewDIVarAddress;
+ if (DIVar.hasComplexAddress()) {
+ for (unsigned i = 0, n = DIVar.getNumAddrElements(); i < n; ++i) {
+ NewDIVarAddress.push_back(
+ ConstantInt::get(Int64Ty, DIVar.getAddrElement(i)));
+ }
+ }
+ NewDIVarAddress.push_back(ConstantInt::get(Int64Ty, DIBuilder::OpDeref));
+ DIVariable NewDIVar = Builder.createComplexVariable(
+ DIVar.getTag(), DIVar.getContext(), DIVar.getName(),
+ DIVar.getFile(), DIVar.getLineNumber(), DIVar.getType(),
+ NewDIVarAddress, DIVar.getArgNumber());
+
+ // Insert llvm.dbg.declare in the same basic block as the original alloca,
+ // and remove old llvm.dbg.declare.
+ BasicBlock *BB = AI->getParent();
+ Builder.insertDeclare(NewAllocaAddress, NewDIVar, BB);
+ DDI->eraseFromParent();
+ return true;
+}