[llvm] [RemoveDIs] Read/write DbgRecords directly from/to bitcode (PR #83251)

[Jeremy Morse via llvm-commits]

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@@ -409,26 +423,49 @@ ValueEnumerator::ValueEnumerator(const Module &M,
 
     for (const BasicBlock &BB : F)
       for (const Instruction &I : BB) {
+        // Local metadata is enumerated during function-incorporation, but
+        // any ConstantAsMetadata arguments in a DIArgList should be examined
+        // now.
+        auto EnumerateNonLocalValuesFromMetadata = [&](Metadata *MD) {
+          assert(MD && "Metadata unexpectedly null");
+          if (const auto *AL = dyn_cast<DIArgList>(MD)) {
+            for (const auto *VAM : AL->getArgs()) {
+              if (isa<ConstantAsMetadata>(VAM))
+                EnumerateMetadata(&F, VAM);
+            }
+            return;
+          }
+
+          if (!isa<LocalAsMetadata>(MD))
+            EnumerateMetadata(&F, MD);
+        };
+
+        for (DbgRecord &DR : I.getDbgValueRange()) {
+          if (DPLabel *DPL = dyn_cast<DPLabel>(&DR)) {
+            EnumerateMetadata(&F, DPL->getLabel());
+            EnumerateMetadata(&F, &*DPL->getDebugLoc());
+            continue;
+          }
+          // Enumerate non-local location metadata.
+          DPValue &DPV = cast<DPValue>(DR);
+          EnumerateNonLocalValuesFromMetadata(DPV.getRawLocation());
+          EnumerateMetadata(&F, DPV.getExpression());
+          EnumerateMetadata(&F, DPV.getVariable());
+          EnumerateMetadata(&F, &*DPV.getDebugLoc());
+          if (DPV.isDbgAssign()) {
+            EnumerateNonLocalValuesFromMetadata(DPV.getRawAddress());
+            EnumerateMetadata(&F, DPV.getAssignID());
+            EnumerateMetadata(&F, DPV.getAddressExpression());
+          }
+        }
         for (const Use &Op : I.operands()) {
           auto *MD = dyn_cast<MetadataAsValue>(&Op);
           if (!MD) {
             EnumerateOperandType(Op);
             continue;
           }
 
-          // Local metadata is enumerated during function-incorporation, but
-          // any ConstantAsMetadata arguments in a DIArgList should be examined
-          // now.
-          if (isa<LocalAsMetadata>(MD->getMetadata()))
-            continue;
-          if (auto *AL = dyn_cast<DIArgList>(MD->getMetadata())) {
-            for (auto *VAM : AL->getArgs())
-              if (isa<ConstantAsMetadata>(VAM))
-                EnumerateMetadata(&F, VAM);
-            continue;
-          }
-
-          EnumerateMetadata(&F, MD->getMetadata());
----------------
jmorse wrote:

Deleting this hunk is going to knacker anyone not running in RemoveDIs mode right now, yes? IMO it's worth stick a comment in saying it's scheduled for removal instead.

https://github.com/llvm/llvm-project/pull/83251