r337678 - [Analyzer] Quick Fix for exponential execution time when simpilifying complex additive expressions

Adam Balogh via cfe-commits cfe-commits at lists.llvm.org
Mon Jul 23 03:50:20 PDT 2018


Author: baloghadamsoftware
Date: Mon Jul 23 03:50:20 2018
New Revision: 337678

URL: http://llvm.org/viewvc/llvm-project?rev=337678&view=rev
Log:
[Analyzer] Quick Fix for exponential execution time when simpilifying complex additive expressions

Patch https://reviews.llvm.org/rC329780 not only rearranges comparisons but
also binary expressions. This latter behavior is not protected by the analyzer
option. Hower, since no complexity threshold is enforced to the symbols this
may result in exponential execution time if the expressions are too complex:
https://bugs.llvm.org/show_bug.cgi?id=38208. For a quick fix we extended the
analyzer option to also cover the additive cases.

This is only a temporary fix, the final solution should be enforcing the
complexity threshold to the symbols.

Differential Revision: https://reviews.llvm.org/D49536


Modified:
    cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h
    cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
    cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
    cfe/trunk/test/Analysis/constraint_manager_negate_difference.c
    cfe/trunk/test/Analysis/iterator-range.cpp
    cfe/trunk/test/Analysis/plist-macros.cpp
    cfe/trunk/test/Analysis/svalbuilder-rearrange-comparisons.c

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=337678&r1=337677&r2=337678&view=diff
==============================================================================
--- cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h (original)
+++ cfe/trunk/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h Mon Jul 23 03:50:20 2018
@@ -318,8 +318,8 @@ private:
   /// \sa shouldDisplayNotesAsEvents
   Optional<bool> DisplayNotesAsEvents;
 
-  /// \sa shouldAggressivelySimplifyRelationalComparison
-  Optional<bool> AggressiveRelationalComparisonSimplification;
+  /// \sa shouldAggressivelySimplifyBinaryOperation
+  Optional<bool> AggressiveBinaryOperationSimplification;
 
   /// \sa getCTUDir
   Optional<StringRef> CTUDir;
@@ -690,19 +690,19 @@ public:
   /// to false when unset.
   bool shouldDisplayNotesAsEvents();
 
-  /// Returns true if SValBuilder should rearrange comparisons of symbolic
-  /// expressions which consist of a sum of a symbol and a concrete integer
-  /// into the format where symbols are on the left-hand side and the integer
-  /// is on the right. This is only done if both symbols and both concrete
-  /// integers are signed, greater than or equal to the quarter of the minimum
-  /// value of the type and less than or equal to the quarter of the maximum
-  /// value of that type.
-  ///
-  /// A + n <REL> B + m becomes A - B <REL> m - n, where A and B symbolic,
-  /// n and m are integers. <REL> is any of '==', '!=', '<', '<=', '>' or '>='.
-  /// The rearrangement also happens with '-' instead of '+' on either or both
-  /// side and also if any or both integers are missing.
-  bool shouldAggressivelySimplifyRelationalComparison();
+  /// Returns true if SValBuilder should rearrange comparisons and additive
+  /// operations of symbolic expressions which consist of a sum of a symbol and
+  /// a concrete integer into the format where symbols are on the left-hand
+  /// side and the integer is on the right. This is only done if both symbols
+  /// and both concrete integers are signed, greater than or equal to the
+  /// quarter of the minimum value of the type and less than or equal to the
+  /// quarter of the maximum value of that type.
+  ///
+  /// A + n <OP> B + m becomes A - B <OP> m - n, where A and B symbolic,
+  /// n and m are integers. <OP> is any of '==', '!=', '<', '<=', '>', '>=',
+  /// '+' or '-'. The rearrangement also happens with '-' instead of '+' on
+  // either or both side and also if any or both integers are missing.
+  bool shouldAggressivelySimplifyBinaryOperation();
 
   /// Returns the directory containing the CTU related files.
   StringRef getCTUDir();

Modified: cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp?rev=337678&r1=337677&r2=337678&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp Mon Jul 23 03:50:20 2018
@@ -463,12 +463,12 @@ bool AnalyzerOptions::shouldDisplayNotes
   return DisplayNotesAsEvents.getValue();
 }
 
-bool AnalyzerOptions::shouldAggressivelySimplifyRelationalComparison() {
-  if (!AggressiveRelationalComparisonSimplification.hasValue())
-    AggressiveRelationalComparisonSimplification =
-      getBooleanOption("aggressive-relational-comparison-simplification",
+bool AnalyzerOptions::shouldAggressivelySimplifyBinaryOperation() {
+  if (!AggressiveBinaryOperationSimplification.hasValue())
+    AggressiveBinaryOperationSimplification =
+      getBooleanOption("aggressive-binary-operation-simplification",
                        /*Default=*/false);
-  return AggressiveRelationalComparisonSimplification.getValue();
+  return AggressiveBinaryOperationSimplification.getValue();
 }
 
 StringRef AnalyzerOptions::getCTUDir() {

Modified: cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp?rev=337678&r1=337677&r2=337678&view=diff
==============================================================================
--- cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp (original)
+++ cfe/trunk/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp Mon Jul 23 03:50:20 2018
@@ -456,14 +456,17 @@ static Optional<NonLoc> tryRearrange(Pro
   auto &Opts =
     StateMgr.getOwningEngine()->getAnalysisManager().getAnalyzerOptions();
 
+  // FIXME: After putting complexity threshold to the symbols we can always
+  //        rearrange additive operations but rearrange comparisons only if
+  //        option is set.
+  if(!Opts.shouldAggressivelySimplifyBinaryOperation())
+    return None;
+
   SymbolRef LSym = Lhs.getAsSymbol();
   if (!LSym)
     return None;
 
-  // Always rearrange additive operations but rearrange comparisons only if
-  // option is set.
-  if (BinaryOperator::isComparisonOp(Op) &&
-      Opts.shouldAggressivelySimplifyRelationalComparison()) {
+  if (BinaryOperator::isComparisonOp(Op)) {
     SingleTy = LSym->getType();
     if (ResultTy != SVB.getConditionType())
       return None;

Modified: cfe/trunk/test/Analysis/constraint_manager_negate_difference.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/constraint_manager_negate_difference.c?rev=337678&r1=337677&r2=337678&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/constraint_manager_negate_difference.c (original)
+++ cfe/trunk/test/Analysis/constraint_manager_negate_difference.c Mon Jul 23 03:50:20 2018
@@ -1,4 +1,4 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=debug.ExprInspection,core.builtin -analyzer-config aggressive-relational-comparison-simplification=true -verify %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.ExprInspection,core.builtin -analyzer-config aggressive-binary-operation-simplification=true -verify %s
 
 void clang_analyzer_eval(int);
 

Modified: cfe/trunk/test/Analysis/iterator-range.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/iterator-range.cpp?rev=337678&r1=337677&r2=337678&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/iterator-range.cpp (original)
+++ cfe/trunk/test/Analysis/iterator-range.cpp Mon Jul 23 03:50:20 2018
@@ -1,5 +1,5 @@
-// RUN: %clang_analyze_cc1 -std=c++11 -analyzer-checker=core,cplusplus,alpha.cplusplus.IteratorRange -analyzer-eagerly-assume -analyzer-config aggressive-relational-comparison-simplification=true -analyzer-config c++-container-inlining=false %s -verify
-// RUN: %clang_analyze_cc1 -std=c++11 -analyzer-checker=core,cplusplus,alpha.cplusplus.IteratorRange -analyzer-eagerly-assume -analyzer-config aggressive-relational-comparison-simplification=true -analyzer-config c++-container-inlining=true -DINLINE=1 %s -verify
+// RUN: %clang_analyze_cc1 -std=c++11 -analyzer-checker=core,cplusplus,alpha.cplusplus.IteratorRange -analyzer-eagerly-assume -analyzer-config aggressive-binary-operation-simplification=true -analyzer-config c++-container-inlining=false %s -verify
+// RUN: %clang_analyze_cc1 -std=c++11 -analyzer-checker=core,cplusplus,alpha.cplusplus.IteratorRange -analyzer-eagerly-assume -analyzer-config aggressive-binary-operation-simplification=true -analyzer-config c++-container-inlining=true -DINLINE=1 %s -verify
 
 #include "Inputs/system-header-simulator-cxx.h"
 

Modified: cfe/trunk/test/Analysis/plist-macros.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/plist-macros.cpp?rev=337678&r1=337677&r2=337678&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/plist-macros.cpp (original)
+++ cfe/trunk/test/Analysis/plist-macros.cpp Mon Jul 23 03:50:20 2018
@@ -637,6 +637,69 @@ void test2(int *p) {
 // CHECK-NEXT:         <key>end</key>
 // CHECK-NEXT:          <array>
 // CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>36</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>36</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:        </dict>
+// CHECK-NEXT:       </array>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>event</string>
+// CHECK-NEXT:      <key>location</key>
+// CHECK-NEXT:      <dict>
+// CHECK-NEXT:       <key>line</key><integer>36</integer>
+// CHECK-NEXT:       <key>col</key><integer>7</integer>
+// CHECK-NEXT:       <key>file</key><integer>0</integer>
+// CHECK-NEXT:      </dict>
+// CHECK-NEXT:      <key>ranges</key>
+// CHECK-NEXT:      <array>
+// CHECK-NEXT:        <array>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>36</integer>
+// CHECK-NEXT:          <key>col</key><integer>7</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:         <dict>
+// CHECK-NEXT:          <key>line</key><integer>36</integer>
+// CHECK-NEXT:          <key>col</key><integer>25</integer>
+// CHECK-NEXT:          <key>file</key><integer>0</integer>
+// CHECK-NEXT:         </dict>
+// CHECK-NEXT:        </array>
+// CHECK-NEXT:      </array>
+// CHECK-NEXT:      <key>depth</key><integer>0</integer>
+// CHECK-NEXT:      <key>extended_message</key>
+// CHECK-NEXT:      <string>Assuming the condition is true</string>
+// CHECK-NEXT:      <key>message</key>
+// CHECK-NEXT:      <string>Assuming the condition is true</string>
+// CHECK-NEXT:     </dict>
+// CHECK-NEXT:     <dict>
+// CHECK-NEXT:      <key>kind</key><string>control</string>
+// CHECK-NEXT:      <key>edges</key>
+// CHECK-NEXT:       <array>
+// CHECK-NEXT:        <dict>
+// CHECK-NEXT:         <key>start</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>36</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:           <dict>
+// CHECK-NEXT:            <key>line</key><integer>36</integer>
+// CHECK-NEXT:            <key>col</key><integer>7</integer>
+// CHECK-NEXT:            <key>file</key><integer>0</integer>
+// CHECK-NEXT:           </dict>
+// CHECK-NEXT:          </array>
+// CHECK-NEXT:         <key>end</key>
+// CHECK-NEXT:          <array>
+// CHECK-NEXT:           <dict>
 // CHECK-NEXT:            <key>line</key><integer>37</integer>
 // CHECK-NEXT:            <key>col</key><integer>5</integer>
 // CHECK-NEXT:            <key>file</key><integer>0</integer>

Modified: cfe/trunk/test/Analysis/svalbuilder-rearrange-comparisons.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Analysis/svalbuilder-rearrange-comparisons.c?rev=337678&r1=337677&r2=337678&view=diff
==============================================================================
--- cfe/trunk/test/Analysis/svalbuilder-rearrange-comparisons.c (original)
+++ cfe/trunk/test/Analysis/svalbuilder-rearrange-comparisons.c Mon Jul 23 03:50:20 2018
@@ -1,4 +1,4 @@
-// RUN: %clang_analyze_cc1 -analyzer-checker=debug.ExprInspection,core.builtin -analyzer-config aggressive-relational-comparison-simplification=true -verify %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=debug.ExprInspection,core.builtin -analyzer-config aggressive-binary-operation-simplification=true -verify %s
 
 void clang_analyzer_dump(int x);
 void clang_analyzer_eval(int x);




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