[analyzer] Analysis: Silence checkers

Summary:
This patch introduces a new `analyzer-config` configuration:
`-analyzer-config silence-checkers`
which could be used to silence the given checkers.

It accepts a semicolon separated list, packed into quotation marks, e.g:
`-analyzer-config silence-checkers="core.DivideZero;core.NullDereference"`

It could be used to "disable" core checkers, so they model the analysis as
before, just if some of them are too noisy it prevents to emit reports.

This patch also adds support for that new option to the scan-build.
Passing the option `-disable-checker core.DivideZero` to the scan-build
will be transferred to `-analyzer-config silence-checkers=core.DivideZero`.

Reviewed By: NoQ, Szelethus

Differential Revision: https://reviews.llvm.org/D66042

llvm-svn: 369078

1 files changed, 18 insertions, 8 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/BugReporter.cpp b/clang/lib/StaticAnalyzer/Core/BugReporter.cpp
index 4cfcdee1c3a..37a3ddecf7a 100644
--- a/clang/lib/StaticAnalyzer/Core/BugReporter.cpp
+++ b/clang/lib/StaticAnalyzer/Core/BugReporter.cpp
@@ -1924,15 +1924,22 @@ PathDiagnosticBuilder::PathDiagnosticBuilder(
 
 std::unique_ptr<PathDiagnostic>
 PathDiagnosticBuilder::generate(const PathDiagnosticConsumer *PDC) const {
-
-  if (!PDC->shouldGenerateDiagnostics())
-    return generateEmptyDiagnosticForReport(R, getSourceManager());
-
   PathDiagnosticConstruct Construct(PDC, ErrorNode, R);
 
   const SourceManager &SM = getSourceManager();
   const BugReport *R = getBugReport();
   const AnalyzerOptions &Opts = getAnalyzerOptions();
+  StringRef ErrorTag = ErrorNode->getLocation().getTag()->getTagDescription();
+
+  // See whether we need to silence the checker/package.
+  // FIXME: This will not work if the report was emitted with an incorrect tag.
+  for (const std::string &CheckerOrPackage : Opts.SilencedCheckersAndPackages) {
+    if (ErrorTag.startswith(CheckerOrPackage))
+      return nullptr;
+  }
+
+  if (!PDC->shouldGenerateDiagnostics())
+    return generateEmptyDiagnosticForReport(R, getSourceManager());
 
   // Construct the final (warning) event for the bug report.
   auto EndNotes = VisitorsDiagnostics->find(ErrorNode);
@@ -2029,7 +2036,6 @@ PathDiagnosticBuilder::generate(const PathDiagnosticConsumer *PDC) const {
   return std::move(Construct.PD);
 }
 
-
 //===----------------------------------------------------------------------===//
 // Methods for BugType and subclasses.
 //===----------------------------------------------------------------------===//
@@ -2646,9 +2652,13 @@ GRBugReporter::generatePathDiagnostics(
   Optional<PathDiagnosticBuilder> PDB =
       PathDiagnosticBuilder::findValidReport(bugReports, *this);
 
-  if (PDB)
-    for (PathDiagnosticConsumer *PC : consumers)
-      (*Out)[PC] = PDB->generate(PC);
+  if (PDB) {
+    for (PathDiagnosticConsumer *PC : consumers) {
+      if (std::unique_ptr<PathDiagnostic> PD = PDB->generate(PC)) {
+        (*Out)[PC] = std::move(PD);
+      }
+    }
+  }
 
   return Out;
 }