[clang][analyzer] Record entry-point CFG size in per-entry-point metrics (#163351)

MaxCFGSize does not make sense in the context of per-entry-point metric.
Moreover, it gets polluted by the syntax-only checks that run before
path-sensitive analysis: the first entry point analized by
path-sensitive analysis will have MaxCFGSize set to the max CFG across
all syntax-only-analyzed entry points, which has little meaning.

This change unbundles the per-TU statistic MaxCFGSize and per-EP
statistic CFGSize.

--

CPP-7099

Author: necto

clang/lib/StaticAnalyzer/Frontend/AnalysisConsumer.cpp

@@ -62,7 +62,9 @@ ALWAYS_ENABLED_STATISTIC(
     "The # of visited basic blocks in the analyzed functions.");
 ALWAYS_ENABLED_STATISTIC(PercentReachableBlocks,
                          "The % of reachable basic blocks.");
-STAT_MAX(MaxCFGSize, "The maximum number of basic blocks in a function.");
+ALWAYS_ENABLED_STATISTIC(MaxCFGSize,
+                         "The maximum number of basic blocks in a function.");
+static UnsignedEPStat CFGSize("CFGSize");
 //===----------------------------------------------------------------------===//
 // AnalysisConsumer declaration.
 //===----------------------------------------------------------------------===//
@@ -783,15 +785,19 @@ void AnalysisConsumer::HandleCode(Decl *D, AnalysisMode Mode,
 void AnalysisConsumer::RunPathSensitiveChecks(Decl *D,
                                               ExprEngine::InliningModes IMode,
                                               SetOfConstDecls *VisitedCallees) {
+  auto *CFG = Mgr->getCFG(D);
+
   // Construct the analysis engine.  First check if the CFG is valid.
   // FIXME: Inter-procedural analysis will need to handle invalid CFGs.
-  if (!Mgr->getCFG(D))
+  if (!CFG)
     return;
 
   // See if the LiveVariables analysis scales.
   if (!Mgr->getAnalysisDeclContext(D)->getAnalysis<RelaxedLiveVariables>())
     return;
 
+  CFGSize.set(CFG->size());
+
   ExprEngine Eng(CTU, *Mgr, VisitedCallees, &FunctionSummaries, IMode);
 
   // Execute the worklist algorithm.

clang/test/Analysis/analyzer-stats/entry-point-stats.cpp

@@ -8,9 +8,9 @@
 // CHECK-NEXT:   "c:@F@fib#i#": {
 // CHECK-NEXT:     "File": "{{.*}}entry-point-stats.cpp",
 // CHECK-NEXT:     "DebugName": "fib(unsigned int)",
+// CHECK-NEXT:     "CFGSize": "5",
 // CHECK-NEXT:     "PathRunningTime": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxBugClassSize": "{{[0-9]+}}",
-// CHECK-NEXT:     "MaxCFGSize": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxQueueSize": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxReachableSize": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxTimeSpentSolvingZ3Queries": "{{[0-9]+}}",
@@ -45,9 +45,9 @@
 // CHECK-NEXT:   "c:@F@main#I#**C#": {
 // CHECK-NEXT:     "File": "{{.*}}entry-point-stats.cpp",
 // CHECK-NEXT:     "DebugName": "main(int, char **)",
+// CHECK-NEXT:     "CFGSize": "3",
 // CHECK-NEXT:     "PathRunningTime": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxBugClassSize": "{{[0-9]+}}",
-// CHECK-NEXT:     "MaxCFGSize": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxQueueSize": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxReachableSize": "{{[0-9]+}}",
 // CHECK-NEXT:     "MaxTimeSpentSolvingZ3Queries": "{{[0-9]+}}",