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-rw-r--r--llvm/lib/CodeGen/LiveDebugVariables.cpp38
1 files changed, 11 insertions, 27 deletions
diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 9de33d6..ce898cd 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -119,33 +119,17 @@ public:
DIExpression::replaceArg(Expression, OpIdx, DuplicatingIdx);
}
}
- // FIXME: Debug values referencing 64+ unique machine locations are rare and
- // currently unsupported for performance reasons. If we can verify that
- // performance is acceptable for such debug values, we can increase the
- // bit-width of LocNoCount to 14 to enable up to 16384 unique machine
- // locations. We will also need to verify that this does not cause issues
- // with LiveDebugVariables' use of IntervalMap.
- if (LocNoVec.size() < 64) {
- LocNoCount = LocNoVec.size();
- if (LocNoCount > 0) {
- LocNos = std::make_unique<unsigned[]>(LocNoCount);
- std::copy(LocNoVec.begin(), LocNoVec.end(), loc_nos_begin());
- }
- } else {
- LLVM_DEBUG(dbgs() << "Found debug value with 64+ unique machine "
- "locations, dropping...\n");
- LocNoCount = 1;
- // Turn this into an undef debug value list; right now, the simplest form
- // of this is an expression with one arg, and an undef debug operand.
- Expression =
- DIExpression::get(Expr.getContext(), {dwarf::DW_OP_LLVM_arg, 0,
- dwarf::DW_OP_stack_value});
- if (auto FragmentInfoOpt = Expr.getFragmentInfo())
- Expression = *DIExpression::createFragmentExpression(
- Expression, FragmentInfoOpt->OffsetInBits,
- FragmentInfoOpt->SizeInBits);
- LocNos = std::make_unique<unsigned[]>(LocNoCount);
- LocNos[0] = UndefLocNo;
+ // A debug value referencing 64+ unique machine locations is very likely
+ // to be the result of a bug earlier in the pipeline. If by some means this
+ // limit is validly reached, then we can add a byte to the size of
+ // LocNoCount.
+ assert(LocNoVec.size() < 64 &&
+ "debug value containing 64+ unique machine locations is not "
+ "supported by Live Debug Variables");
+ LocNoCount = LocNoVec.size();
+ if (LocNoCount > 0) {
+ LocNos.reset(new unsigned[LocNoCount]());
+ std::copy(LocNoVec.begin(), LocNoVec.end(), loc_nos_begin());
}
}