[clang] [Clang] Introduce OverflowBehaviorType for fine-grained overflow control (PR #148914)

[Justin Stitt via cfe-commits]

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@@ -5776,6 +5826,51 @@ QualType ASTContext::getBTFTagAttributedType(const BTFTypeTagAttr *BTFAttr,
   return QualType(Ty, 0);
 }
 
+QualType ASTContext::getOverflowBehaviorType(const OverflowBehaviorAttr *Attr,
+                                             QualType Underlying) const {
+  IdentifierInfo *II = Attr->getBehaviorKind();
+  StringRef IdentName = II->getName();
+  OverflowBehaviorType::OverflowBehaviorKind Kind;
+  if (IdentName == "wrap") {
+    Kind = OverflowBehaviorType::OverflowBehaviorKind::Wrap;
+  } else if (IdentName == "no_wrap") {
+    Kind = OverflowBehaviorType::OverflowBehaviorKind::NoWrap;
+  } else {
+    return Underlying;
+  }
+
+  return getOverflowBehaviorType(Kind, Underlying);
+}
+
+QualType ASTContext::getOverflowBehaviorType(
+    OverflowBehaviorType::OverflowBehaviorKind Kind,
+    QualType Underlying) const {
+  llvm::FoldingSetNodeID ID;
+  OverflowBehaviorType::Profile(ID, Underlying, Kind);
+  void *InsertPos = nullptr;
+
+  if (OverflowBehaviorType *OBT =
+          OverflowBehaviorTypes.FindNodeOrInsertPos(ID, InsertPos)) {
+    return QualType(OBT, 0);
+  }
+
+  QualType Canonical;
+  if (!Underlying.isCanonical()) {
+    Canonical = getOverflowBehaviorType(Kind, getCanonicalType(Underlying));
+    OverflowBehaviorType *NewOBT =
+        OverflowBehaviorTypes.FindNodeOrInsertPos(ID, InsertPos);
+    assert(!NewOBT && "Shouldn't be in the map!");
+    (void)NewOBT;
----------------
JustinStitt wrote:

fixed in fixed with [`04af8bf`](https://github.com/llvm/llvm-project/pull/148914/commits/04af8bf6e9620c71673a435d3b2eebccd7db3682)

https://github.com/llvm/llvm-project/pull/148914