[analyzer] Add time-trace scopes for high-level analyzer steps (#125508)

Specifically, add a scope for 
- each work-list step,
- each entry point,
- each checker run within a step, and
- bug-suppression phase at the end of the analysis of an entry-point.

These scopes add no perceptible run-time overhead when time-tracing is
disabled. You can enable it and generate a time trace using the
`-ftime-trace=file.json` option.

See also the RFC:
https://discourse.llvm.org/t/analyzer-rfc-ftime-trace-time-scopes-for-steps-and-entry-points/84343

--
CPP-6065

1 files changed, 37 insertions, 8 deletions

diff --git a/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp b/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp
index 91c9b08..189d7d6 100644
--- a/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp
+++ b/clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp
@@ -39,6 +39,7 @@
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
 #include "llvm/Support/Program.h"
+#include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include <memory>
@@ -358,9 +359,40 @@ private:
 
   /// Print \p S to stderr if \c Opts.AnalyzerDisplayProgress is set.
   void reportAnalyzerProgress(StringRef S);
-}; // namespace
-} // end anonymous namespace
+};
 
+std::string timeTraceScopeDeclName(StringRef FunName, const Decl *D) {
+  if (llvm::timeTraceProfilerEnabled()) {
+    if (const NamedDecl *ND = dyn_cast<NamedDecl>(D))
+      return (FunName + " " + ND->getQualifiedNameAsString()).str();
+    return (FunName + " <anonymous> ").str();
+  }
+  return "";
+}
+
+llvm::TimeTraceMetadata timeTraceScopeDeclMetadata(const Decl *D) {
+  // If time-trace profiler is not enabled, this function is never called.
+  assert(llvm::timeTraceProfilerEnabled());
+  if (const auto &Loc = D->getBeginLoc(); Loc.isValid()) {
+    const auto &SM = D->getASTContext().getSourceManager();
+    std::string DeclName = AnalysisDeclContext::getFunctionName(D);
+    return llvm::TimeTraceMetadata{
+        std::move(DeclName), SM.getFilename(Loc).str(),
+        static_cast<int>(SM.getExpansionLineNumber(Loc))};
+  }
+  return llvm::TimeTraceMetadata{"", ""};
+}
+
+void flushReports(llvm::Timer *BugReporterTimer, BugReporter &BR) {
+  llvm::TimeTraceScope TCS{"Flushing reports"};
+  // Display warnings.
+  if (BugReporterTimer)
+    BugReporterTimer->startTimer();
+  BR.FlushReports();
+  if (BugReporterTimer)
+    BugReporterTimer->stopTimer();
+}
+} // namespace
 
 //===----------------------------------------------------------------------===//
 // AnalysisConsumer implementation.
@@ -658,6 +690,8 @@ AnalysisConsumer::getModeForDecl(Decl *D, AnalysisMode Mode) {
 void AnalysisConsumer::HandleCode(Decl *D, AnalysisMode Mode,
                                   ExprEngine::InliningModes IMode,
                                   SetOfConstDecls *VisitedCallees) {
+  llvm::TimeTraceScope TCS(timeTraceScopeDeclName("HandleCode", D),
+                           [D]() { return timeTraceScopeDeclMetadata(D); });
   if (!D->hasBody())
     return;
   Mode = getModeForDecl(D, Mode);
@@ -742,12 +776,7 @@ void AnalysisConsumer::RunPathSensitiveChecks(Decl *D,
   if (Mgr->options.visualizeExplodedGraphWithGraphViz)
     Eng.ViewGraph(Mgr->options.TrimGraph);
 
-  // Display warnings.
-  if (BugReporterTimer)
-    BugReporterTimer->startTimer();
-  Eng.getBugReporter().FlushReports();
-  if (BugReporterTimer)
-    BugReporterTimer->stopTimer();
+  flushReports(BugReporterTimer.get(), Eng.getBugReporter());
 }
 
 //===----------------------------------------------------------------------===//