Added AnalyzerStatsChecker, a path sensitive check that reports visitation statistics about analysis. Running clang with the -analyzer-stats flag will emit warnings containing the information. We can then run a postanalysis script to take this data and give useful information about how much the analyzer missed in a project.

llvm-svn: 113568

clang/include/clang/Checker/PathSensitive/GRExprEngine.h

@@ -264,6 +264,7 @@ public:
 
   // Functions for external checking of whether we have unfinished work
   bool wasBlockAborted() const { return CoreEngine.wasBlockAborted(); }
+  bool hasEmptyWorkList() const { return !CoreEngine.getWorkList()->hasWork(); }
   bool hasWorkRemaining() const {
     return wasBlockAborted() || CoreEngine.getWorkList()->hasWork();
   }

clang/include/clang/Driver/CC1Options.td

@@ -64,6 +64,8 @@ def analysis_WarnSizeofPointer : Flag<"-warn-sizeof-pointer">,
   HelpText<"Warn about unintended use of sizeof() on pointer expressions">;
 def analysis_WarnIdempotentOps : Flag<"-analyzer-check-idempotent-operations">,
   HelpText<"Warn about idempotent operations">;
+def analysis_AnalyzerStats : Flag<"-analyzer-stats">,
+  HelpText<"Emit warnings with analyzer statistics">;
 
 def analyzer_store : Separate<"-analyzer-store">,
   HelpText<"Source Code Analysis - Abstract Memory Store Models">;

clang/include/clang/Frontend/AnalyzerOptions.h

@@ -65,6 +65,7 @@ public:
   unsigned AnalyzeAll : 1;
   unsigned AnalyzerDisplayProgress : 1;
   unsigned AnalyzeNestedBlocks : 1;
+  unsigned AnalyzerStats : 1;
   unsigned EagerlyAssume : 1;
   unsigned IdempotentOps : 1;
   unsigned PurgeDead : 1;
@@ -73,7 +74,6 @@ public:
   unsigned VisualizeEGUbi : 1;
   unsigned EnableExperimentalChecks : 1;
   unsigned EnableExperimentalInternalChecks : 1;
-  unsigned EnableIdempotentOperationChecker : 1;
   unsigned InlineCall : 1;
   unsigned UnoptimizedCFG : 1;
 
@@ -85,6 +85,7 @@ public:
     AnalyzeAll = 0;
     AnalyzerDisplayProgress = 0;
     AnalyzeNestedBlocks = 0;
+    AnalyzerStats = 0;
     EagerlyAssume = 0;
     PurgeDead = 1;
     TrimGraph = 0;

clang/lib/Checker/AnalysisConsumer.cpp

@@ -350,6 +350,10 @@ static void ActionGRExprEngine(AnalysisConsumer &C, AnalysisManager& mgr,
       || C.Opts.EnableExperimentalInternalChecks)
     RegisterIdempotentOperationChecker(Eng);
 
+  // Enable AnalyzerStatsChecker if it was given as an argument
+  if (C.Opts.AnalyzerStats)
+    RegisterAnalyzerStatsChecker(Eng);
+
   // Set the graph auditor.
   llvm::OwningPtr<ExplodedNode::Auditor> Auditor;
   if (mgr.shouldVisualizeUbigraph()) {

clang/lib/Checker/AnalyzerStatsChecker.cpp

@@ -0,0 +1,104 @@
+//==--AnalyzerStatsChecker.cpp - Analyzer visitation statistics --*- C++ -*-==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+// This file reports various statistics about analyzer visitation.
+//===----------------------------------------------------------------------===//
+
+#include "clang/Checker/PathSensitive/CheckerVisitor.h"
+#include "clang/Checker/PathSensitive/ExplodedGraph.h"
+#include "clang/Checker/BugReporter/BugReporter.h"
+#include "GRExprEngineExperimentalChecks.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/ADT/SmallPtrSet.h"
+
+using namespace clang;
+
+namespace {
+class AnalyzerStatsChecker : public CheckerVisitor<AnalyzerStatsChecker> {
+public:
+  static void *getTag();
+  void VisitEndAnalysis(ExplodedGraph &G, BugReporter &B, GRExprEngine &Eng);
+
+private:
+  llvm::SmallPtrSet<const CFGBlock*, 256> reachable;
+};
+}
+
+void *AnalyzerStatsChecker::getTag() {
+  static int x = 0;
+  return &x;
+}
+
+void clang::RegisterAnalyzerStatsChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new AnalyzerStatsChecker());
+}
+
+void AnalyzerStatsChecker::VisitEndAnalysis(ExplodedGraph &G,
+                                            BugReporter &B,
+                                            GRExprEngine &Eng) {
+  const CFG *C  = 0;
+  const Decl *D = 0;
+  const LocationContext *LC = 0;
+  const SourceManager &SM = B.getSourceManager();
+
+  // Iterate over explodedgraph
+  for (ExplodedGraph::node_iterator I = G.nodes_begin();
+      I != G.nodes_end(); ++I) {
+    const ProgramPoint &P = I->getLocation();
+    // Save the LocationContext if we don't have it already
+    if (!LC)
+      LC = P.getLocationContext();
+
+    if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
+      const CFGBlock *CB = BE->getDst();
+      reachable.insert(CB);
+    }
+  }
+
+  // Get the CFG and the Decl of this block
+  C = LC->getCFG();
+  D = LC->getAnalysisContext()->getDecl();
+
+  unsigned total = 0, unreachable = 0;
+
+  // Find CFGBlocks that were not covered by any node
+  for (CFG::const_iterator I = C->begin(); I != C->end(); ++I) {
+    const CFGBlock *CB = *I;
+    ++total;
+    // Check if the block is unreachable
+    if (!reachable.count(CB)) {
+      ++unreachable;
+    }
+  }
+
+  // We never 'reach' the entry block, so correct the unreachable count
+  unreachable--;
+
+  // Generate the warning string
+  llvm::SmallString<128> buf;
+  llvm::raw_svector_ostream output(buf);
+  PresumedLoc Loc = SM.getPresumedLoc(D->getLocation());
+  output << Loc.getFilename() << " : ";
+
+  if (isa<FunctionDecl>(D) || isa<ObjCMethodDecl>(D)) {
+    const NamedDecl *ND = cast<NamedDecl>(D);
+    output << ND;
+  }
+  else if (isa<BlockDecl>(D)) {
+    output << "block(line:" << Loc.getLine() << ":col:" << Loc.getColumn();
+  }
+
+  output << " -> Total CFGBlocks: " << total << " | Unreachable CFGBlocks: "
+      << unreachable << " | Aborted Block: "
+      << (Eng.wasBlockAborted() ? "no" : "yes")
+      << " | Empty WorkList: "
+      << (Eng.hasEmptyWorkList() ? "yes" : "no") << "\n";
+
+  B.EmitBasicReport("Analyzer Statistics", "Internal Statistics", output.str(),
+      D->getLocation());
+}

clang/lib/Checker/CMakeLists.txt

@@ -7,6 +7,7 @@ add_clang_library(clangChecker
   AggExprVisitor.cpp
   AnalysisConsumer.cpp
   AnalysisManager.cpp
+  AnalyzerStatsChecker.cpp
   ArrayBoundChecker.cpp
   AttrNonNullChecker.cpp
   BasicConstraintManager.cpp

clang/lib/Checker/GRExprEngineExperimentalChecks.h

@@ -19,6 +19,7 @@ namespace clang {
 
 class GRExprEngine;
 
+void RegisterAnalyzerStatsChecker(GRExprEngine &Eng);
 void RegisterCStringChecker(GRExprEngine &Eng);
 void RegisterIdempotentOperationChecker(GRExprEngine &Eng);
 void RegisterMallocChecker(GRExprEngine &Eng);

clang/lib/Frontend/CompilerInvocation.cpp

@@ -99,6 +99,8 @@ static void AnalyzerOptsToArgs(const AnalyzerOptions &Opts,
     Res.push_back("-analyzer-display-progress");
   if (Opts.AnalyzeNestedBlocks)
     Res.push_back("-analyzer-opt-analyze-nested-blocks");
+  if (Opts.AnalyzerStats)
+    Res.push_back("-analyzer-stats");
   if (Opts.EagerlyAssume)
     Res.push_back("-analyzer-eagerly-assume");
   if (!Opts.PurgeDead)
@@ -815,6 +817,7 @@ static void ParseAnalyzerArgs(AnalyzerOptions &Opts, ArgList &Args,
   Opts.AnalyzerDisplayProgress = Args.hasArg(OPT_analyzer_display_progress);
   Opts.AnalyzeNestedBlocks =
     Args.hasArg(OPT_analyzer_opt_analyze_nested_blocks);
+  Opts.AnalyzerStats = Args.hasArg(OPT_analysis_AnalyzerStats);
   Opts.PurgeDead = !Args.hasArg(OPT_analyzer_no_purge_dead);
   Opts.EagerlyAssume = Args.hasArg(OPT_analyzer_eagerly_assume);
   Opts.AnalyzeSpecificFunction = Args.getLastArgValue(OPT_analyze_function);

clang/test/Analysis/analyzer-stats.c

@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -analyze -analyzer-experimental-internal-checks -analyzer-check-objc-mem -analyzer-check-dead-stores -verify -Wno-unreachable-code -analyzer-opt-analyze-nested-blocks -analyzer-stats %s
+
+int foo();
+
+int test() { // expected-warning{{Total CFGBlocks}}
+  int a = 1;
+  a = 34 / 12;
+
+  if (foo())
+    return a;
+
+  a /= 4;
+  return a;
+}