Control analysis-based diagnostics with #pragma (#136323)

Previously, analysis-based diagnostics (like -Wconsumed) had to be
enabled at file scope in order to be run at the end of each function
body. This meant that they did not respect #pragma clang diagnostic
enabling or disabling the diagnostic.

Now, these pragmas can control the diagnostic emission.

Fixes #42199

1 files changed, 31 insertions, 12 deletions

diff --git a/clang/lib/Sema/AnalysisBasedWarnings.cpp b/clang/lib/Sema/AnalysisBasedWarnings.cpp
index 32c7ee9..3d8eaf0 100644
--- a/clang/lib/Sema/AnalysisBasedWarnings.cpp
+++ b/clang/lib/Sema/AnalysisBasedWarnings.cpp
@@ -2492,9 +2492,11 @@ public:
   CalledOnceInterProceduralData CalledOnceData;
 };
 
-static unsigned isEnabled(DiagnosticsEngine &D, unsigned diag) {
-  return (unsigned)!D.isIgnored(diag, SourceLocation());
-}
+template <typename... Ts>
+static bool areAnyEnabled(DiagnosticsEngine &D, SourceLocation Loc,
+                          Ts... Diags) {
+  return (!D.isIgnored(Diags, Loc) || ...);
+};
 
 sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s)
     : S(s), IPData(std::make_unique<InterProceduralData>()),
@@ -2503,23 +2505,37 @@ sema::AnalysisBasedWarnings::AnalysisBasedWarnings(Sema &s)
       NumUninitAnalysisVariables(0), MaxUninitAnalysisVariablesPerFunction(0),
       NumUninitAnalysisBlockVisits(0),
       MaxUninitAnalysisBlockVisitsPerFunction(0) {
+}
+
+// We need this here for unique_ptr with forward declared class.
+sema::AnalysisBasedWarnings::~AnalysisBasedWarnings() = default;
 
+sema::AnalysisBasedWarnings::Policy
+sema::AnalysisBasedWarnings::getPolicyInEffectAt(SourceLocation Loc) {
   using namespace diag;
   DiagnosticsEngine &D = S.getDiagnostics();
+  Policy P;
 
-  DefaultPolicy.enableCheckUnreachable =
-      isEnabled(D, warn_unreachable) || isEnabled(D, warn_unreachable_break) ||
-      isEnabled(D, warn_unreachable_return) ||
-      isEnabled(D, warn_unreachable_loop_increment);
+  // Note: The enabled checks should be kept in sync with the switch in
+  // SemaPPCallbacks::PragmaDiagnostic().
+  P.enableCheckUnreachable =
+      PolicyOverrides.enableCheckUnreachable ||
+      areAnyEnabled(D, Loc, warn_unreachable, warn_unreachable_break,
+                    warn_unreachable_return, warn_unreachable_loop_increment);
 
-  DefaultPolicy.enableThreadSafetyAnalysis = isEnabled(D, warn_double_lock);
+  P.enableThreadSafetyAnalysis = PolicyOverrides.enableThreadSafetyAnalysis ||
+                                 areAnyEnabled(D, Loc, warn_double_lock);
 
-  DefaultPolicy.enableConsumedAnalysis =
-      isEnabled(D, warn_use_in_invalid_state);
+  P.enableConsumedAnalysis = PolicyOverrides.enableConsumedAnalysis ||
+                             areAnyEnabled(D, Loc, warn_use_in_invalid_state);
+  return P;
 }
 
-// We need this here for unique_ptr with forward declared class.
-sema::AnalysisBasedWarnings::~AnalysisBasedWarnings() = default;
+void sema::AnalysisBasedWarnings::clearOverrides() {
+  PolicyOverrides.enableCheckUnreachable = false;
+  PolicyOverrides.enableConsumedAnalysis = false;
+  PolicyOverrides.enableThreadSafetyAnalysis = false;
+}
 
 static void flushDiagnostics(Sema &S, const sema::FunctionScopeInfo *fscope) {
   for (const auto &D : fscope->PossiblyUnreachableDiags)
@@ -2870,6 +2886,9 @@ void clang::sema::AnalysisBasedWarnings::IssueWarnings(
     AC.getCFG();
   }
 
+  // Clear any of our policy overrides.
+  clearOverrides();
+
   // Collect statistics about the CFG if it was built.
   if (S.CollectStats && AC.isCFGBuilt()) {
     ++NumFunctionsAnalyzed;