[clang] nonblocking/nonallocating attributes (was: nolock/noalloc) (PR #84983)

[via cfe-commits]

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@@ -4780,42 +4781,38 @@ struct FunctionEffectWithCondition {
 
   /// Return a textual description of the effect, and its condition, if any.
   std::string description() const;
-
-  friend bool operator<(const FunctionEffectWithCondition &LHS,
-                        const FunctionEffectWithCondition &RHS) {
-    if (LHS.Effect < RHS.Effect)
-      return true;
-    if (RHS.Effect < LHS.Effect)
-      return false;
-    return LHS.Cond.expr() < RHS.Cond.expr();
-  }
 };
 
 /// Support iteration in parallel through a pair of FunctionEffect and
 /// FunctionEffectCondition containers.
 template <typename Container> class FunctionEffectIterator {
-  const Container &Outer;
-  size_t Idx;
+  friend Container;
+
+  const Container *Outer = nullptr;
+  size_t Idx = 0;
 
 public:
-  FunctionEffectIterator(const Container &O, size_t I) : Outer(O), Idx(I) {}
+  FunctionEffectIterator();
+  FunctionEffectIterator(const Container &O, size_t I) : Outer(&O), Idx(I) {}
   bool operator==(const FunctionEffectIterator &Other) const {
     return Idx == Other.Idx;
   }
   bool operator!=(const FunctionEffectIterator &Other) const {
     return Idx != Other.Idx;
   }
 
-  // prefix increment
   FunctionEffectIterator operator++() {
     ++Idx;
     return *this;
   }
 
-  FunctionEffectWithCondition operator*() const {
-    const bool HasConds = !Outer.Conditions.empty();
-    return FunctionEffectWithCondition{Outer.Effects[Idx],
-                                       HasConds ? Outer.Conditions[Idx]
+  const FunctionEffectWithCondition operator*() const {
+    // Returns a const struct because storing into it would not accomplish
+    // anything.
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Sirraide wrote:

That may be true, but I don’t think we return a `const` object by value pretty much ever; imo just returning by value is enough to clarify that.

https://github.com/llvm/llvm-project/pull/84983