[analyzer] For now, don't inline C++ standard library functions.

This is a (heavy-handed) solution to PR13724 -- until we know we can do
a good job inlining the STL, it's best to be consistent and not generate
more false positives than we did before. We can selectively whitelist
certain parts of the 'std' namespace that are known to be safe.

This is controlled by analyzer config option 'c++-stdlib-inlining', which
can be set to "true" or "false".

This commit also adds control for whether or not to inline any templated
functions (member or non-member), under the config option
'c++-template-inlining'. This option is currently on by default.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@163548 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h b/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h
index 5dba158f1238003356d939663975e25bf270d53e..3065098695422052e5dfc1d7bb7b39be75d32092 100644 (file)
--- a/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h
+++ b/include/clang/StaticAnalyzer/Core/AnalyzerOptions.h
@@ -17,7 +17,9 @@
 
 #include <string>
 #include <vector>
+#include "clang/Basic/LLVM.h"
 #include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/IntrusiveRefCntPtr.h"
 
 namespace clang {
@@ -166,6 +168,12 @@ public:
 private:
   /// Controls which C++ member functions will be considered for inlining.
   CXXInlineableMemberKind CXXMemberInliningMode;
+  
+  llvm::Optional<bool> IncludeTemporaryDtorsInCFG;
+  llvm::Optional<bool> InlineCXXStandardLibrary;
+  llvm::Optional<bool> InlineTemplateFunctions;
+  
+  bool getBooleanOption(StringRef Name, bool DefaultVal = false) const;
 
 public:
   /// Returns the option controlling which C++ member functions will be
@@ -183,6 +191,19 @@ public:
   /// non-empty value is considered to be 'true'.
   bool includeTemporaryDtorsInCFG() const;
 
+  /// Returns whether or not C++ standard library functions may be considered
+  /// for inlining.
+  ///
+  /// This is controlled by the 'c++-stdlib-inlining' config option, which
+  /// accepts the values "true" and "false".
+  bool mayInlineCXXStandardLibrary() const;
+
+  /// Returns whether or not templated functions may be considered for inlining.
+  ///
+  /// This is controlled by the 'c++-template-inlining' config option, which
+  /// accepts the values "true" and "false".
+  bool mayInlineTemplateFunctions() const;
+
 public:
   AnalyzerOptions() : CXXMemberInliningMode() {
     AnalysisStoreOpt = RegionStoreModel;

diff --git a/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp b/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
index 9e45a115283a9a65781bda6e64a6e3d99f5ca41d..b410890f8eeb793763756cb876194db6e48222c7 100644 (file)
--- a/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
+++ b/lib/StaticAnalyzer/Core/AnalyzerOptions.cpp
@@ -47,6 +47,36 @@ AnalyzerOptions::mayInlineCXXMemberFunction(CXXInlineableMemberKind K) const {
   return CXXMemberInliningMode >= K;
 }
 
+bool AnalyzerOptions::getBooleanOption(StringRef Name, bool DefaultVal) const {
+  // FIXME: We should emit a warning here if the value is something other than
+  // "true", "false", or the empty string (meaning the default value),
+  // but the AnalyzerOptions doesn't have access to a diagnostic engine.
+  return llvm::StringSwitch<bool>(Config.lookup(Name))
+    .Case("true", true)
+    .Case("false", false)
+    .Default(DefaultVal);
+}
+
 bool AnalyzerOptions::includeTemporaryDtorsInCFG() const {
-  return !Config.lookup("cfg-temporary-dtors").empty();
+  if (!IncludeTemporaryDtorsInCFG.hasValue())
+    const_cast<llvm::Optional<bool> &>(IncludeTemporaryDtorsInCFG) =
+      getBooleanOption("cfg-temporary-dtors");
+  
+  return *IncludeTemporaryDtorsInCFG;
+}
+
+bool AnalyzerOptions::mayInlineCXXStandardLibrary() const {
+  if (!InlineCXXStandardLibrary.hasValue())
+    const_cast<llvm::Optional<bool> &>(InlineCXXStandardLibrary) =
+      getBooleanOption("c++-stdlib-inlining");
+  
+  return *InlineCXXStandardLibrary;
+}
+
+bool AnalyzerOptions::mayInlineTemplateFunctions() const {
+  if (!InlineTemplateFunctions.hasValue())
+    const_cast<llvm::Optional<bool> &>(InlineTemplateFunctions) =
+      getBooleanOption("c++-template-inlining", /*Default=*/true);
+  
+  return *InlineTemplateFunctions;
 }

diff --git a/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp b/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
index fd94c1926b5eaab0af171321aa5e4d004060c972..9bf63c5b9610203a074523f21541902e4b4a6090 100644 (file)
--- a/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
+++ b/lib/StaticAnalyzer/Core/ExprEngineCallAndReturn.cpp
@@ -257,6 +257,21 @@ static unsigned getNumberStackFrames(const LocationContext *LCtx) {
   return count;  
 }
 
+static bool IsInStdNamespace(const FunctionDecl *FD) {
+  const DeclContext *DC = FD->getEnclosingNamespaceContext();
+  const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(DC);
+  if (!ND)
+    return false;
+  
+  while (const DeclContext *Parent = ND->getParent()) {
+    if (!isa<NamespaceDecl>(Parent))
+      break;
+    ND = cast<NamespaceDecl>(Parent);
+  }
+
+  return ND->getName() == "std";
+}
+
 // Determine if we should inline the call.
 bool ExprEngine::shouldInlineDecl(const Decl *D, ExplodedNode *Pred) {
   AnalysisDeclContext *CalleeADC = AMgr.getAnalysisDeclContext(D);
@@ -287,6 +302,21 @@ bool ExprEngine::shouldInlineDecl(const Decl *D, ExplodedNode *Pred) {
       return false;
   }
 
+  if (getContext().getLangOpts().CPlusPlus) {
+    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) {
+      // Conditionally allow the inlining of template functions.
+      if (!getAnalysisManager().options.mayInlineTemplateFunctions())
+        if (FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate)
+          return false;
+
+      // Conditionally allow the inlining of C++ standard library functions.
+      if (!getAnalysisManager().options.mayInlineCXXStandardLibrary())
+        if (getContext().getSourceManager().isInSystemHeader(FD->getLocation()))
+          if (IsInStdNamespace(FD))
+            return false;
+    }
+  }
+
   // It is possible that the live variables analysis cannot be
   // run.  If so, bail out.
   if (!CalleeADC->getAnalysis<RelaxedLiveVariables>())

diff --git a/test/Analysis/inlining/stl.cpp b/test/Analysis/inlining/stl.cpp
new file mode 100644 (file)
index 0000000..d9b3e02
--- /dev/null
+++ b/test/Analysis/inlining/stl.cpp
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,unix.Malloc,debug.ExprInspection -analyzer-ipa=dynamic -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,unix.Malloc,debug.ExprInspection -analyzer-ipa=dynamic -analyzer-config c++-stdlib-inlining=true -DINLINE=1 -verify %s
+
+#include "../system-header-simulator-cxx.h"
+
+void clang_analyzer_eval(bool);
+
+void testVector(std::vector<int> &nums) {
+  if (nums.begin()) return;
+  if (nums.end()) return;
+  
+  clang_analyzer_eval(nums.size() == 0);
+#if INLINE
+  // expected-warning@-2 {{TRUE}}
+#else
+  // expected-warning@-4 {{UNKNOWN}}
+#endif
+}
+
+void testException(std::exception e) {
+  // Notice that the argument is NOT passed by reference, so we can devirtualize.
+  const char *x = e.what();
+  clang_analyzer_eval(x == 0);
+#if INLINE
+  // expected-warning@-2 {{TRUE}}
+#else
+  // expected-warning@-4 {{UNKNOWN}}
+#endif
+}

diff --git a/test/Analysis/system-header-simulator-cxx.h b/test/Analysis/system-header-simulator-cxx.h
new file mode 100644 (file)
index 0000000..e762d0a
--- /dev/null
+++ b/test/Analysis/system-header-simulator-cxx.h
@@ -0,0 +1,57 @@
+#pragma clang system_header
+
+namespace std {
+  template <class T1, class T2>
+  struct pair {
+    T1 first;
+    T2 second;
+    
+    pair() : first(), second() {}
+    pair(const T1 &a, const T2 &b) : first(a), second(b) {}
+    
+    template<class U1, class U2>
+    pair(const pair<U1, U2> &other) : first(other.first), second(other.second) {}
+  };
+  
+  typedef __typeof__(sizeof(int)) size_t;
+  
+  template<typename T>
+  class vector {
+    T *_start;
+    T *_finish;
+    T *_end_of_storage;
+  public:
+    vector() : _start(0), _finish(0), _end_of_storage(0) {}
+    ~vector();
+    
+    size_t size() const {
+      return size_t(_finish - _start);
+    }
+    
+    void push_back();
+    T pop_back();
+
+    T &operator[](size_t n) {
+      return _start[n];
+    }
+    
+    const T &operator[](size_t n) const {
+      return _start[n];
+    }
+    
+    T *begin() { return _start; }
+    const T *begin() const { return _start; }
+
+    T *end() { return _finish; }
+    const T *end() const { return _finish; }
+  };
+  
+  class exception {
+  public:
+    exception() throw();
+    virtual ~exception() throw();
+    virtual const char *what() const throw() {
+      return 0;
+    }
+  };
+}

diff --git a/test/Analysis/temp-obj-dtors-cfg-output.cpp b/test/Analysis/temp-obj-dtors-cfg-output.cpp
index d13083ddf011b9232a0d9b9339549c911c735eb5..c8844754bef8f6424bc85fe567d360a0786f5ca8 100644 (file)
--- a/test/Analysis/temp-obj-dtors-cfg-output.cpp
+++ b/test/Analysis/temp-obj-dtors-cfg-output.cpp
@@ -1,5 +1,5 @@
 // RUN: rm -f %t
-// RUN: %clang_cc1 -analyze -analyzer-checker=debug.DumpCFG -analyzer-config cfg-temporary-dtors=1 %s > %t 2>&1
+// RUN: %clang_cc1 -analyze -analyzer-checker=debug.DumpCFG -analyzer-config cfg-temporary-dtors=true %s > %t 2>&1
 // RUN: FileCheck --input-file=%t %s
 // XPASS: *
 

diff --git a/test/Analysis/templates.cpp b/test/Analysis/templates.cpp
index 671aa7858204190985e7abd71ac4f30890c31d37..faa5c1a762094c1104b80ea1616f669f82b8cbab 100644 (file)
--- a/test/Analysis/templates.cpp
+++ b/test/Analysis/templates.cpp
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -analyze -analyzer-checker=core,debug.ExprInspection -fblocks -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,debug.ExprInspection -fblocks -analyzer-config c++-template-inlining=false -DNO_INLINE -verify %s
 
 void clang_analyzer_eval(bool);
 
@@ -39,6 +40,11 @@ inline unsigned array_lengthof(T (&)[N]) {
 
 void testNonTypeTemplateInstantiation() {
   const char *S[] = { "a", "b" };
-  clang_analyzer_eval(array_lengthof(S) == 2); // expected-warning{{TRUE}}
+  clang_analyzer_eval(array_lengthof(S) == 2);
+#ifndef NO_INLINE
+  // expected-warning@-2 {{TRUE}}
+#else
+  // expected-warning@-4 {{UNKNOWN}}
+#endif
 }