[clang] [clang][analyzer] Teach the BlockInCriticalSectionChecker about O_NONBLOCK streams (PR #127049)

[Gábor Horváth via cfe-commits]

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@@ -337,6 +391,28 @@ void BlockInCriticalSectionChecker::reportBlockInCritSection(
      << "' inside of critical section";
   auto R = std::make_unique<PathSensitiveBugReport>(BlockInCritSectionBugType,
                                                     os.str(), ErrNode);
+  // for 'read' and 'recv' call, check whether it's file descriptor(first
+  // argument) is
+  // created by 'open' API with O_NONBLOCK flag or is equal to -1, they will
+  // not cause block in these situations, don't report
+  StringRef FuncName = Call.getCalleeIdentifier()->getName();
+  if (FuncName == "read" || FuncName == "recv") {
+    SVal SV = Call.getArgSVal(0);
+    SValBuilder &SVB = C.getSValBuilder();
+    ProgramStateRef state = C.getState();
+    ConditionTruthVal CTV =
+        state->areEqual(SV, SVB.makeIntVal(-1, C.getASTContext().IntTy));
+    if (CTV.isConstrainedTrue())
+      return;
+
+    if (SymbolRef SR = SV.getAsSymbol()) {
+      if (!O_NONBLOCKValue)
+        O_NONBLOCKValue = tryExpandAsInteger(
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Xazax-hun wrote:

Oh, I completely missed that! Sorry! :)

https://github.com/llvm/llvm-project/pull/127049