r251702 - Reapply r251621 "[Analyzer] Widening loops which do not exit"

[Sean Eveson via cfe-commits]

Author: seaneveson
Date: Fri Oct 30 10:23:57 2015
New Revision: 251702

URL: http://llvm.org/viewvc/llvm-project?rev=251702&view=rev
Log:
Reapply r251621 "[Analyzer] Widening loops which do not exit"

It was not the cause of the build bot failure.

Added:
    cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/LoopWidening.h
      - copied unchanged from r251696, cfe/trunk/include/clang/StaticAnalyzer/Core/PathSensitive/LoopWidening.h
    cfe/trunk/lib/StaticAnalyzer/Core/LoopWidening.cpp
      - copied unchanged from r251696, cfe/trunk/lib/StaticAnalyzer/Core/LoopWidening.cpp
    cfe/trunk/test/Analysis/loop-widening.c
      - copied unchanged from r251696, cfe/trunk/test/Analysis/loop-widening.c
Modified:
    cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h
    cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
    cfe/trunk/lib/StaticAnalyzer/Core/CMakeLists.txt
    cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp
    cfe/trunk/test/Analysis/analyzer-config.c
    cfe/trunk/test/Analysis/analyzer-config.cpp

Modified: cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h?rev=251702&r1=251701&r2=251702&view=diff
==============================================================================
--- cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h (original)
+++ cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h Fri Oct 30 10:23:57 2015
@@ -262,6 +262,9 @@ private:
   /// \sa shouldInlineLambdas
   Optional<bool> InlineLambdas;
 
+  /// \sa shouldWidenLoops
+  Optional<bool> WidenLoops;
+
   /// A helper function that retrieves option for a given full-qualified
   /// checker name.
   /// Options for checkers can be specified via 'analyzer-config' command-line
@@ -526,6 +529,10 @@ public:
   /// generated each time a LambdaExpr is visited.
   bool shouldInlineLambdas();
 
+  /// Returns true if the analysis should try to widen loops.
+  /// This is controlled by the 'widen-loops' config option.
+  bool shouldWidenLoops();
+
 public:
   AnalyzerOptions() :
     AnalysisStoreOpt(RegionStoreModel),

Modified: cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp?rev=251702&r1=251701&r2=251702&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp Fri Oct 30 10:23:57 2015
@@ -338,3 +338,9 @@ bool AnalyzerOptions::shouldInlineLambda
     InlineLambdas = getBooleanOption("inline-lambdas", /*Default=*/true);
   return InlineLambdas.getValue();
 }
+
+bool AnalyzerOptions::shouldWidenLoops() {
+  if (!WidenLoops.hasValue())
+    WidenLoops = getBooleanOption("widen-loops", /*Default=*/false);
+  return WidenLoops.getValue();
+}

Modified: cfe/trunk/lib/StaticAnalyzer/Core/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/CMakeLists.txt?rev=251702&r1=251701&r2=251702&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/CMakeLists.txt (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/CMakeLists.txt Fri Oct 30 10:23:57 2015
@@ -28,6 +28,7 @@ add_clang_library(clangStaticAnalyzerCor
   ExprEngineObjC.cpp
   FunctionSummary.cpp
   HTMLDiagnostics.cpp
+  LoopWidening.cpp
   MemRegion.cpp
   PathDiagnostic.cpp
   PlistDiagnostics.cpp

Modified: cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp?rev=251702&r1=251701&r2=251702&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/ExprEngine.cpp Fri Oct 30 10:23:57 2015
@@ -26,6 +26,7 @@
 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/LoopWidening.h"
 #include "llvm/ADT/ImmutableList.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Support/raw_ostream.h"
@@ -1395,8 +1396,25 @@ void ExprEngine::processCFGBlockEntrance
                                          ExplodedNode *Pred) {
   PrettyStackTraceLocationContext CrashInfo(Pred->getLocationContext());
 
+  // If this block is terminated by a loop and it has already been visited the
+  // maximum number of times, widen the loop.
+  unsigned int BlockCount = nodeBuilder.getContext().blockCount();
+  if (BlockCount == AMgr.options.maxBlockVisitOnPath - 1 &&
+      AMgr.options.shouldWidenLoops()) {
+    const Stmt *Term = nodeBuilder.getContext().getBlock()->getTerminator();
+    if (!(Term &&
+          (isa<ForStmt>(Term) || isa<WhileStmt>(Term) || isa<DoStmt>(Term))))
+      return;
+    // Widen.
+    const LocationContext *LCtx = Pred->getLocationContext();
+    ProgramStateRef WidenedState =
+        getWidenedLoopState(Pred->getState(), LCtx, BlockCount, Term);
+    nodeBuilder.generateNode(WidenedState, Pred);
+    return;
+  }
+
   // FIXME: Refactor this into a checker.
-  if (nodeBuilder.getContext().blockCount() >= AMgr.options.maxBlockVisitOnPath) {
+  if (BlockCount >= AMgr.options.maxBlockVisitOnPath) {
     static SimpleProgramPointTag tag(TagProviderName, "Block count exceeded");
     const ExplodedNode *Sink =
                    nodeBuilder.generateSink(Pred->getState(), Pred, &tag);

Modified: cfe/trunk/test/Analysis/analyzer-config.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/analyzer-config.c?rev=251702&r1=251701&r2=251702&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/analyzer-config.c (original)
+++ cfe/trunk/test/Analysis/analyzer-config.c Fri Oct 30 10:23:57 2015
@@ -25,6 +25,7 @@ void foo() {
 // CHECK-NEXT: min-cfg-size-treat-functions-as-large = 14
 // CHECK-NEXT: mode = deep
 // CHECK-NEXT: region-store-small-struct-limit = 2
+// CHECK-NEXT: widen-loops = false
 // CHECK-NEXT: [stats]
-// CHECK-NEXT: num-entries = 14
+// CHECK-NEXT: num-entries = 15
 

Modified: cfe/trunk/test/Analysis/analyzer-config.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/analyzer-config.cpp?rev=251702&r1=251701&r2=251702&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/analyzer-config.cpp (original)
+++ cfe/trunk/test/Analysis/analyzer-config.cpp Fri Oct 30 10:23:57 2015
@@ -36,5 +36,6 @@ public:
 // CHECK-NEXT: min-cfg-size-treat-functions-as-large = 14
 // CHECK-NEXT: mode = deep
 // CHECK-NEXT: region-store-small-struct-limit = 2
+// CHECK-NEXT: widen-loops = false
 // CHECK-NEXT: [stats]
-// CHECK-NEXT: num-entries = 19
+// CHECK-NEXT: num-entries = 20