[llvm] [RemoveDIs][DebugInfo] Add DPValue checks to the verifier, prepare DPValue for parsing support (PR #79810)

[Jeremy Morse via llvm-commits]

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@@ -6152,6 +6175,80 @@ static DISubprogram *getSubprogram(Metadata *LocalScope) {
   return nullptr;
 }
 
+void Verifier::visit(DPValue &DPV) {
+  CheckDI(DPV.getType() == DPValue::LocationType::Value ||
+              DPV.getType() == DPValue::LocationType::Declare ||
+              DPV.getType() == DPValue::LocationType::Assign,
+          "invalid #dbg record type", &DPV, DPV.getType());
+  StringRef Kind;
+  switch (DPV.getType()) {
+  case DPValue::LocationType::Value:
+    Kind = "value";
+    break;
+  case DPValue::LocationType::Declare:
+    Kind = "declare";
+    break;
+  case DPValue::LocationType::Assign:
+    Kind = "assign";
+    break;
+  default:
+    llvm_unreachable("Tried to print a DPValue with an invalid LocationType!");
+  };
+  auto *MD = DPV.getRawLocation();
+  CheckDI(isa<ValueAsMetadata>(MD) || isa<DIArgList>(MD) ||
+              (isa<MDNode>(MD) && !cast<MDNode>(MD)->getNumOperands()),
+          "invalid #dbg_" + Kind + " address/value", &DPV, MD);
+  CheckDI(isa<DILocalVariable>(DPV.getRawVariable()),
+          "invalid #dbg_" + Kind + " variable", &DPV, DPV.getRawVariable());
+  CheckDI(DPV.getExpression(), "missing #dbg_" + Kind + " expression", &DPV,
+          DPV.getExpression());
+
+  if (DPV.isDbgAssign()) {
+    CheckDI(isa<DIAssignID>(DPV.getRawAssignID()),
+            "invalid #dbg_assign DIAssignID", &DPV, DPV.getRawAssignID());
+    const auto *RawAddr = DPV.getRawAddress();
+    CheckDI(
+        isa<ValueAsMetadata>(RawAddr) ||
+            (isa<MDNode>(RawAddr) && !cast<MDNode>(RawAddr)->getNumOperands()),
+        "invalid #dbg_assign address", &DPV, DPV.getRawAddress());
+    CheckDI(DPV.getAddressExpression(),
+            "missing #dbg_assign address expression", &DPV,
+            DPV.getAddressExpression());
+    // All of the linked instructions should be in the same function as DPV.
+    for (Instruction *I : at::getAssignmentInsts(&DPV))
+      CheckDI(DPV.getFunction() == I->getFunction(),
+              "inst not in same function as #dbg_assign", I, &DPV);
+  }
+
+  if (MDNode *N = DPV.getDebugLoc().getAsMDNode()) {
+    CheckDI(isa<DILocation>(N), "invalid #dbg_" + Kind + " location", &DPV, N);
+    visitDILocation(*cast<DILocation>(N));
+  }
+
+  BasicBlock *BB = DPV.getParent();
+  Function *F = BB ? BB->getParent() : nullptr;
----------------
jmorse wrote:

Are there scenarios where people try to verify blocks that are not inserted? If not, IMO we should swallow null-dereferences here (i.e. not check for them) to avoid giving the impression that that's a legitimate configuration.

https://github.com/llvm/llvm-project/pull/79810