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

[Doug Wyatt via cfe-commits]

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@@ -5028,3 +5050,376 @@ void AutoType::Profile(llvm::FoldingSetNodeID &ID, const ASTContext &Context) {
   Profile(ID, Context, getDeducedType(), getKeyword(), isDependentType(),
           getTypeConstraintConcept(), getTypeConstraintArguments());
 }
+
+FunctionEffect::Kind FunctionEffect::oppositeKind() const {
+  switch (kind()) {
+  case Kind::NonBlocking:
+    return Kind::Blocking;
+  case Kind::Blocking:
+    return Kind::NonBlocking;
+  case Kind::NonAllocating:
+    return Kind::Allocating;
+  case Kind::Allocating:
+    return Kind::NonAllocating;
+  case Kind::None:
+    return Kind::None;
+  }
+  llvm_unreachable("unknown effect kind");
+}
+
+StringRef FunctionEffect::name() const {
+  switch (kind()) {
+  case Kind::NonBlocking:
+    return "nonblocking";
+  case Kind::NonAllocating:
+    return "nonallocating";
+  case Kind::Blocking:
+    return "blocking";
+  case Kind::Allocating:
+    return "allocating";
+  case Kind::None:
+    break;
+  }
+  llvm_unreachable("unknown effect kind");
+}
+
+bool FunctionEffectDiff::shouldDiagnoseConversion(
+    QualType SrcType, const FunctionEffectsRef &SrcFX, QualType DstType,
+    const FunctionEffectsRef &DstFX) const {
+
+  switch (EffectKind) {
+  case FunctionEffect::Kind::NonAllocating:
+    // nonallocating can't be added (spoofed) during a conversion, unless we
+    // have nonblocking
+    if (DiffKind == Kind::Added) {
+      for (const auto &CFE : SrcFX) {
+        if (CFE.Effect.kind() == FunctionEffect::Kind::NonBlocking)
+          return false;
+      }
+    }
+    [[fallthrough]];
+  case FunctionEffect::Kind::NonBlocking:
+    // nonblocking can't be added (spoofed) during a conversion.
+    switch (DiffKind) {
+    case Kind::Added:
+      return true;
+    case Kind::Removed:
+      return false;
+    case Kind::ConditionMismatch:
+      return true; // TODO: ???
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dougsonos wrote:

There are better comments around all of these now.

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