[analyzer] Put llvm.Conventions back in alpha

[Szelethus]

Summary

Interestingly, this many year old (when I last looked I remember 2010ish) checker was committed without any tests, so I thought I'd implement them, but I was shocked to see how I barely managed to get it working. The code is severely outdated, I'm not even sure it has ever been used, so I'd propose to move it back into alpha, and possibly even remove it.

[Szelethus]

Added an entry to the website.

[Szelethus]

lib/StaticAnalyzer/Checkers/LLVMConventionsChecker.cpp

193–195

The StringRefpart of this checker doesn't do a thing for me at all (even after a good amount of trying to make it work), but this part of the checker suffers a lot too.

I'm sure we can some up with better ways for this function (and every single one in this file to be honest) now that almost a decade has passed.

[NoQ]

I've actually never noticed this checker until you started updating the website :)

This might be also covered by @rnkovacs's string buffer escape checker - either already or eventually, it'll become just yet another string view API that the checker supports.

test/Analysis/llvm-conventions.cpp

9

I think we should try to re-use (and possibly extend) test/Analysis/inputs/system-header-simulator-cxx.h.

[MTC]

In addition, clang/lib/StaticAnalyzer/README.txt and other related docs in clang/lib/docs/analyzer are also out of date.

www/analyzer/alpha_checks.html

599

Like StringRef, ArrayRef may have similar issues. After this patch landed, maybe we can enhance this checker step by step. By that time, we may need the ideas of the heavy users of the LLVM library.

[Szelethus]

In D53856#1279887, @NoQ wrote:

This might be also covered by @rnkovacs's string buffer escape checker - either already or eventually, it'll become just yet another string view API that the checker supports.

I thought about that too, adding some StringRef specific information to that checker makes more sense then essentially duplicating the logic. However, what @MTC mentioned about ArrayRef<T> would be a neat addition too, and maybe it isn't worth making InnerPointerChecker that general.

@rnkovacs, any thoughts?

[Szelethus]

• Moved std::string implementation from InnerPointerChecker's testfile to the system header simulator header file.

[rnkovacs]

In D53856#1280408, @Szelethus wrote:

In D53856#1279887, @NoQ wrote:

This might be also covered by @rnkovacs's string buffer escape checker - either already or eventually, it'll become just yet another string view API that the checker supports.

I thought about that too, adding some StringRef specific information to that checker makes more sense then essentially duplicating the logic. However, what @MTC mentioned about ArrayRef<T> would be a neat addition too, and maybe it isn't worth making InnerPointerChecker that general.

@rnkovacs, any thoughts?

I agree, adding StringRef support to the buffer escape checker around the time we add string_view will be great. Also, we named it InnerPointerChecker to allow for covering more general structures in the future, so I guess ArrayRefs may also be added eventually. Unfortunately, I have some other tasks to finish before getting to these, so I think this patch is fine now as-is.

[NoQ]

In D53856#1285373, @rnkovacs wrote:

In D53856#1280408, @Szelethus wrote:

In D53856#1279887, @NoQ wrote:

This might be also covered by @rnkovacs's string buffer escape checker - either already or eventually, it'll become just yet another string view API that the checker supports.

I thought about that too, adding some StringRef specific information to that checker makes more sense then essentially duplicating the logic. However, what @MTC mentioned about ArrayRef<T> would be a neat addition too, and maybe it isn't worth making InnerPointerChecker that general.

@rnkovacs, any thoughts?

I agree, adding StringRef support to the buffer escape checker around the time we add string_view will be great. Also, we named it InnerPointerChecker to allow for covering more general structures in the future, so I guess ArrayRefs may also be added eventually. Unfortunately, I have some other tasks to finish before getting to these, so I think this patch is fine now as-is.

I also agree that we should generally try harder to determine common logic behind checkers. Eg., MallocChecker and StreamChecker should be the same checker, or at least re-use this fairly large chunk of common code that implements the overall idea of "one function produces a symbol, then another function consumes it, and the consuming function always needs to be called on that symbol, while the symbol should not be used in certain (almost all) manners after it is consumed".

include/clang/StaticAnalyzer/Checkers/Checkers.td

 def Containers : Package<"containers">, InPackage<CoreFoundation>;
 
 def LocalizabilityAlpha : Package<"localizability">, InPackage<CocoaAlpha>;
 def LocalizabilityOptIn : Package<"localizability">, InPackage<CocoaOptIn>;
 
 def MPI : Package<"mpi">, InPackage<OptIn>;
 
 def LLVM : Package<"llvm">;
+def LLVMAlpha : Package<"llvm">, InPackage<Alpha>, Hidden;
 
 // The APIModeling package is for checkers that model APIs and don't perform
 // any diagnostics. These checkers are always turned on; this package is
 // intended for API modeling that is not controlled by the target triple.
 def APIModeling : Package<"apiModeling">, Hidden;
 def GoogleAPIModeling : Package<"google">, InPackage<APIModeling>;
 
 def Debug : Package<"debug">;
let ParentPackage = MPI in {
   DescFile<"MPIChecker.cpp">;
 }
 
 //===----------------------------------------------------------------------===//
 // Checkers for LLVM development.
 //===----------------------------------------------------------------------===//
 
 def LLVMConventionsChecker : Checker<"Conventions">,
-  InPackage<LLVM>,
+  InPackage<LLVMAlpha>,
   HelpText<"Check code for LLVM codebase conventions">,
   DescFile<"LLVMConventionsChecker.cpp">;
 
 
 
 //===----------------------------------------------------------------------===//
 // Checkers modeling Google APIs.
 //===----------------------------------------------------------------------===//

lib/StaticAnalyzer/Checkers/LLVMConventionsChecker.cpp

 // Generic type checking routines.
 //===----------------------------------------------------------------------===//
 
 static bool IsLLVMStringRef(QualType T) {
   const RecordType *RT = T->getAs<RecordType>();
   if (!RT)
     return false;
 
-  return StringRef(QualType(RT, 0).getAsString()) ==
-          "class StringRef";
+  return StringRef(QualType(RT, 0).getAsString()) == "class StringRef";
 }
 
 /// Check whether the declaration is semantically inside the top-level
 /// namespace named by ns.
 static bool InNamespace(const Decl *D, StringRef NS) {
   const NamespaceDecl *ND = dyn_cast<NamespaceDecl>(D->getDeclContext());
   if (!ND)
     return false;
BR.EmitBasicReport(DeclWithIssue, Checker, desc, "LLVM Conventions", desc,
                      VDLoc, Init->getSourceRange());
 }
 
 //===----------------------------------------------------------------------===//
 // CHECK: Clang AST nodes should not have fields that can allocate
 //   memory.
 //===----------------------------------------------------------------------===//
 
 static bool AllocatesMemory(QualType T) {
   return IsStdVector(T) || IsStdString(T) || IsSmallVector(T);
 }
 
 // This type checking could be sped up via dynamic programming.
 static bool IsPartOfAST(const CXXRecordDecl *R) {
   if (IsClangStmt(R) || IsClangType(R) || IsClangDecl(R) || IsClangAttr(R))
     return true;
 
   for (const auto &BS : R->bases()) {
     QualType T = BS.getType();

test/Analysis/Inputs/system-header-simulator-cxx.h

 // Like the compiler, the static analyzer treats some functions differently if
 // they come from a system header -- for example, it is assumed that system
 // functions do not arbitrarily free() their parameters, and that some bugs
 // found in system headers cannot be fixed by the user and should be
 // suppressed.
 #pragma clang system_header
 
 typedef unsigned char uint8_t;
 
 typedef __typeof__(sizeof(int)) size_t;
 typedef __typeof__((char*)0-(char*)0) ptrdiff_t;
 void *memmove(void *s1, const void *s2, size_t n);
 
 namespace std {
+  typedef size_t size_type;
+#if __cplusplus >= 201103L
+  using nullptr_t = decltype(nullptr);
+#endif
+}
+
+namespace std {
   struct input_iterator_tag { };
   struct output_iterator_tag { };
   struct forward_iterator_tag : public input_iterator_tag { };
   struct bidirectional_iterator_tag : public forward_iterator_tag { };
   struct random_access_iterator_tag : public bidirectional_iterator_tag { };
 
   template <typename Iterator> struct iterator_traits {
     typedef typename Iterator::difference_type difference_type;
public:
     iterator end() { return iterator(); }
     const_iterator end() const { return const_iterator(); }
     const_iterator cend() const { return const_iterator(); }
 
     T& front() { return *begin(); }
     const T& front() const { return *begin(); }
   };
 
+  template <typename CharT>
+  class basic_string {
+  public:
+    basic_string();
+    basic_string(const CharT *s);
+
+    ~basic_string();
+    void clear();
+
+    basic_string &operator=(const basic_string &str);
+    basic_string &operator+=(const basic_string &str);
+
+    const CharT *c_str() const;
+    const CharT *data() const;
+    CharT *data();
+
+    basic_string &append(size_type count, CharT ch);
+    basic_string &assign(size_type count, CharT ch);
+    basic_string &erase(size_type index, size_type count);
+    basic_string &insert(size_type index, size_type count, CharT ch);
+    basic_string &replace(size_type pos, size_type count, const basic_string &str);
+    void pop_back();
+    void push_back(CharT ch);
+    void reserve(size_type new_cap);
+    void resize(size_type count);
+    void shrink_to_fit();
+    void swap(basic_string &other);
+  };
+
+  typedef basic_string<char> string;
+  typedef basic_string<wchar_t> wstring;
+#if __cplusplus >= 201103L
+  typedef basic_string<char16_t> u16string;
+  typedef basic_string<char32_t> u32string;
+#endif
+
   class exception {
   public:
     exception() throw();
     virtual ~exception() throw();
     virtual const char *what() const throw() {
       return 0;
     }
   };

test/Analysis/diagnostics/explicit-suppression.cpp

class C {
   // The virtual function is to make C not trivially copy assignable so that we call the
   // variant of std::copy() that does not defer to memmove().
   virtual int f();
 };
 
 void testCopyNull(C *I, C *E) {
   std::copy(I, E, (C *)0);
 #ifndef SUPPRESSED
-  // expected-warning@../Inputs/system-header-simulator-cxx.h:627 {{Called C++ object pointer is null}}
+  // expected-warning@../Inputs/system-header-simulator-cxx.h:668 {{Called C++ object pointer is null}}
 #endif
 }

test/Analysis/inner-pointer.cpp

-//RUN: %clang_analyze_cc1 -analyzer-checker=cplusplus.InnerPointer %s -analyzer-output=text -verify
+// RUN: %clang_analyze_cc1 -analyzer-checker=cplusplus.InnerPointer \
+// RUN:   %s -analyzer-output=text -verify
 
+#include "Inputs/system-header-simulator-cxx.h"
 namespace std {
 
-typedef int size_type;
-
-template <typename CharT>
-class basic_string {
-public:
-  basic_string();
-  basic_string(const CharT *s);
-
-  ~basic_string();
-  void clear();
-
-  basic_string &operator=(const basic_string &str);
-  basic_string &operator+=(const basic_string &str);
-
-  const CharT *c_str() const;
-  const CharT *data() const;
-  CharT *data();
-
-  basic_string &append(size_type count, CharT ch);
-  basic_string &assign(size_type count, CharT ch);
-  basic_string &erase(size_type index, size_type count);
-  basic_string &insert(size_type index, size_type count, CharT ch);
-  basic_string &replace(size_type pos, size_type count, const basic_string &str);
-  void pop_back();
-  void push_back(CharT ch);
-  void reserve(size_type new_cap);
-  void resize(size_type count);
-  void shrink_to_fit();
-  void swap(basic_string &other);
-};
-
-typedef basic_string<char> string;
-typedef basic_string<wchar_t> wstring;
-typedef basic_string<char16_t> u16string;
-typedef basic_string<char32_t> u32string;
-
 template <typename T>
 void func_ref(T &a);
 
 template <typename T>
 void func_const_ref(const T &a);
 
 template <typename T>
 void func_value(T a);

test/Analysis/llvm-conventions.cpp

+// RUN: %clang_analyze_cc1 -analyzer-checker=core,alpha.llvm.Conventions \
+// RUN:   -std=c++14 -verify  %s
+
+#include "Inputs/system-header-simulator-cxx.h"
+
+//===----------------------------------------------------------------------===//
+// Forward declarations for StringRef tests.
+//===----------------------------------------------------------------------===//
+
+using size_t = unsigned long;
+using size_type = size_t;
+
+namespace std {
+
+template <class T>
+struct numeric_limits { const static bool is_signed; };
+
+} // end of namespace std
+
+namespace llvm {
+
+template <class T>
+struct iterator_range;
+
+template <class Func>
+struct function_ref;
+
+struct hash_code;
+
+template <class T>
+struct SmallVectorImpl;
+
+struct APInt;
+
+class StringRef {
+public:
+  static const size_t npos = ~size_t(0);
+  using iterator = const char *;
+  using const_iterator = const char *;
+  using size_type = size_t;
+
+  /*implicit*/ StringRef() = default;
+  StringRef(std::nullptr_t) = delete;
+  /*implicit*/ StringRef(const char *Str);
+  /*implicit*/ constexpr StringRef(const char *data, size_t length);
+  /*implicit*/ StringRef(const std::string &Str);
+
+  static StringRef withNullAsEmpty(const char *data);
+  iterator begin() const;
+  iterator end() const;
+  const unsigned char *bytes_begin() const;
+  const unsigned char *bytes_end() const;
+  iterator_range<const unsigned char *> bytes() const;
+  const char *data() const;
+  bool empty() const;
+  size_t size() const;
+  char front() const;
+  char back() const;
+  template <typename Allocator>
+  StringRef copy(Allocator &A) const;
+  bool equals(StringRef RHS) const;
+  bool equals_lower(StringRef RHS) const;
+  int compare(StringRef RHS) const;
+  int compare_lower(StringRef RHS) const;
+  int compare_numeric(StringRef RHS) const;
+  unsigned edit_distance(StringRef Other, bool AllowReplacements = true,
+                         unsigned MaxEditDistance = 0) const;
+  std::string str() const;
+  char operator[](size_t Index) const;
+  template <typename T>
+  typename std::enable_if<std::is_same<T, std::string>::value,
+                          StringRef>::type &
+  operator=(T &&Str) = delete;
+  operator std::string() const;
+  bool startswith(StringRef Prefix) const;
+  bool startswith_lower(StringRef Prefix) const;
+  bool endswith(StringRef Suffix) const;
+  bool endswith_lower(StringRef Suffix) const;
+  size_t find(char C, size_t From = 0) const;
+  size_t find_lower(char C, size_t From = 0) const;
+  size_t find_if(function_ref<bool(char)> F, size_t From = 0) const;
+  size_t find_if_not(function_ref<bool(char)> F, size_t From = 0) const;
+  size_t find(StringRef Str, size_t From = 0) const;
+  size_t find_lower(StringRef Str, size_t From = 0) const;
+  size_t rfind(char C, size_t From = npos) const;
+  size_t rfind_lower(char C, size_t From = npos) const;
+  size_t rfind(StringRef Str) const;
+  size_t rfind_lower(StringRef Str) const;
+  size_t find_first_of(char C, size_t From = 0) const;
+  size_t find_first_of(StringRef Chars, size_t From = 0) const;
+  size_t find_first_not_of(char C, size_t From = 0) const;
+  size_t find_first_not_of(StringRef Chars, size_t From = 0) const;
+  size_t find_last_of(char C, size_t From = npos) const;
+  size_t find_last_of(StringRef Chars, size_t From = npos) const;
+  size_t find_last_not_of(char C, size_t From = npos) const;
+  size_t find_last_not_of(StringRef Chars, size_t From = npos) const;
+  bool contains(StringRef Other) const;
+  bool contains(char C) const;
+  bool contains_lower(StringRef Other) const;
+  bool contains_lower(char C) const;
+  size_t count(char C) const;
+  size_t count(StringRef Str) const;
+  template <typename T>
+  typename std::enable_if<std::numeric_limits<T>::is_signed, bool>::type
+  getAsInteger(unsigned Radix, T &Result) const;
+  template <typename T>
+  typename std::enable_if<!std::numeric_limits<T>::is_signed, bool>::type
+  getAsInteger(unsigned Radix, T &Result) const;
+  template <typename T>
+  typename std::enable_if<std::numeric_limits<T>::is_signed, bool>::type
+  consumeInteger(unsigned Radix, T &Result);
+  template <typename T>
+  typename std::enable_if<!std::numeric_limits<T>::is_signed, bool>::type
+  consumeInteger(unsigned Radix, T &Result);
+  bool getAsInteger(unsigned Radix, APInt &Result) const;
+  bool getAsDouble(double &Result, bool AllowInexact = true) const;
+  std::string lower() const;
+  std::string upper() const;
+  StringRef substr(size_t Start, size_t N = npos) const;
+  StringRef take_front(size_t N = 1) const;
+  StringRef take_back(size_t N = 1) const;
+  StringRef take_while(function_ref<bool(char)> F) const;
+  StringRef take_until(function_ref<bool(char)> F) const;
+  StringRef drop_front(size_t N = 1) const;
+  StringRef drop_back(size_t N = 1) const;
+  StringRef drop_while(function_ref<bool(char)> F) const;
+  StringRef drop_until(function_ref<bool(char)> F) const;
+  bool consume_front(StringRef Prefix);
+  bool consume_back(StringRef Suffix);
+  StringRef slice(size_t Start, size_t End) const;
+  std::pair<StringRef, StringRef> split(char Separator) const;
+  std::pair<StringRef, StringRef> split(StringRef Separator) const;
+  std::pair<StringRef, StringRef> rsplit(StringRef Separator) const;
+  void split(SmallVectorImpl<StringRef> &A,
+             StringRef Separator, int MaxSplit = -1,
+             bool KeepEmpty = true) const;
+  void split(SmallVectorImpl<StringRef> &A, char Separator, int MaxSplit = -1,
+             bool KeepEmpty = true) const;
+  std::pair<StringRef, StringRef> rsplit(char Separator) const;
+  StringRef ltrim(char Char) const;
+  StringRef ltrim(StringRef Chars = " \t\n\v\f\r") const;
+  StringRef rtrim(char Char) const;
+  StringRef rtrim(StringRef Chars = " \t\n\v\f\r") const;
+  StringRef trim(char Char) const;
+  StringRef trim(StringRef Chars = " \t\n\v\f\r") const;
+};
+
+inline bool operator==(StringRef LHS, StringRef RHS);
+inline bool operator!=(StringRef LHS, StringRef RHS);
+inline bool operator<(StringRef LHS, StringRef RHS);
+inline bool operator<=(StringRef LHS, StringRef RHS);
+inline bool operator>(StringRef LHS, StringRef RHS);
+inline bool operator>=(StringRef LHS, StringRef RHS);
+inline std::string &operator+=(std::string &buffer, StringRef string);
+hash_code hash_value(StringRef S);
+template <typename T> struct isPodLike;
+template <> struct isPodLike<StringRef> { static const bool value = true; };
+
+} // end of namespace llvm
+
+//===----------------------------------------------------------------------===//
+// Tests for StringRef.
+//===----------------------------------------------------------------------===//
+
+void temporarayStringToStringRefAssignmentTest() {
+  // TODO: Emit a warning.
+  llvm::StringRef Ref = std::string("Yimmy yummy test.");
+}
+
+void assigningStringToStringRefWithLongerLifetimeTest() {
+  llvm::StringRef Ref;
+  {
+    // TODO: Emit a warning.
+    std::string TmpStr("This is a fine string.");
+    Ref = TmpStr;
+  }
+}
+
+std::string getTemporaryString() {
+  return "One two three.";
+}
+
+void assigningTempStringFromFunctionToStringRefTest() {
+  // TODO: Emit a warning.
+  llvm::StringRef Ref = getTemporaryString();
+}
+
+//===----------------------------------------------------------------------===//
+// Forward declaration for Clang AST nodes.
+//===----------------------------------------------------------------------===//
+
+namespace llvm {
+
+template <class T, int Size>
+struct SmallVector {};
+
+} // end of namespace llvm
+
+namespace clang {
+
+struct Type;
+struct Decl;
+struct Stmt;
+struct Attr;
+
+} // end of namespace clang
+
+//===----------------------------------------------------------------------===//
+// Tests for Clang AST nodes.
+//===----------------------------------------------------------------------===//
+
+namespace clang {
+
+struct Type {
+  std::string str; // expected-warning{{AST class 'Type' has a field 'str' that allocates heap memory (type std::string)}}
+};
+
+} // end of namespace clang
+
+namespace clang {
+
+struct Decl {
+  llvm::SmallVector<int, 5> Vec; // expected-warning{{AST class 'Decl' has a field 'Vec' that allocates heap memory (type llvm::SmallVector<int, 5>)}}
+};
+
+} // end of namespace clang

test/Analysis/temporaries.cpp

 // RUN: %clang_analyze_cc1 -Wno-non-pod-varargs -analyzer-checker=core,cplusplus,debug.ExprInspection -analyzer-config cfg-temporary-dtors=false -verify -w -std=c++03 -analyzer-config eagerly-assume=false %s
 // RUN: %clang_analyze_cc1 -Wno-non-pod-varargs -analyzer-checker=core,cplusplus,debug.ExprInspection -analyzer-config cfg-temporary-dtors=false -verify -w -std=c++11 -analyzer-config eagerly-assume=false %s
 // RUN: %clang_analyze_cc1 -Wno-non-pod-varargs -analyzer-checker=core,cplusplus,debug.ExprInspection -DTEMPORARY_DTORS -verify -w -analyzer-config cfg-temporary-dtors=true,c++-temp-dtor-inlining=true -analyzer-config eagerly-assume=false %s -std=c++11
 // RUN: %clang_analyze_cc1 -Wno-non-pod-varargs -analyzer-checker=core,cplusplus,debug.ExprInspection -DTEMPORARY_DTORS -w -analyzer-config cfg-temporary-dtors=true,c++-temp-dtor-inlining=true -analyzer-config eagerly-assume=false %s -std=c++17
 
 // Note: The C++17 run-line doesn't -verify yet - it is a no-crash test.
 
 extern bool clang_analyzer_eval(bool);
 extern bool clang_analyzer_warnIfReached();
 void clang_analyzer_checkInlined(bool);
 
-#include "Inputs/system-header-simulator-cxx.h";
+#include "Inputs/system-header-simulator-cxx.h"
 
 struct Trivial {
   Trivial(int x) : value(x) {}
   int value;
 };
 
 struct NonTrivial : public Trivial {
   NonTrivial(int x) : Trivial(x) {}

www/analyzer/alpha_checks.html

 Default Checkers</a>. These are checkers with known issues or limitations that
 keep them from being on by default. They are likely to have false positives.
 Bug reports are welcome but will likely not be investigated for some time.
 Patches welcome!
 <ul>
 <li><a href="#clone_alpha_checkers">Clone Alpha Checkers</a></li>
 <li><a href="#core_alpha_checkers">Core Alpha Checkers</a></li>
 <li><a href="#cplusplus_alpha_checkers">C++ Alpha Checkers</a></li>
+<li><a href="#llvm_alpha_checkers">LLVM Checkers</a></li>
 <li><a href="#valist_alpha_checkers">Variable Argument Alpha Checkers</a></li>
 <li><a href="#deadcode_alpha_checkers">Dead Code Alpha Checkers</a></li>
 <li><a href="#osx_alpha_checkers">OS X Alpha Checkers</a></li>
 <li><a href="#security_alpha_checkers">Security Alpha Checkers</a></li>
 <li><a href="#unix_alpha_checkers">Unix Alpha Checkers</a></li>
 </ul>
 
 <!-- ============================= clone alpha ============================= -->

 // Objective-C
 void test(id x) {
   return;
   [x retain]; // warn
 }
 </pre></div></div></td></tr>
 </tbody></table>
 
+<!-- =========================== llvm alpha =========================== -->
+<h3 id="llvm_alpha_checkers">LLVM Checkers</h3>
+<table class="checkers">
+<colgroup><col class="namedescr"><col class="example"></colgroup>
+<thead><tr><td>Name, Description</td><td>Example</td></tr></thead>
+
+<tbody>
+<tr><td><div class="namedescr expandable"><span class="name">
+alpha.llvm.Conventions</span><span class="lang">
+(C)</span><div class="descr">
+Check code for LLVM codebase conventions:
+<ul>
+  <li>A <code>StringRef</code> should not be bound to a temporary std::string
+  whose lifetime is shorter than the <code>StringRef</code>'s.</li>
+  <li>Clang AST nodes should not have fields that can allocate memory.</li>
+</ul>
+</div></div></td>
+<td><div class="exampleContainer expandable">
+<div class="example"><pre>
+<!-- TODO: Add examples, as currently it's hard to get this checker working. -->
+</pre></div></div></td></tr>
+
+</tbody></table>
+
+
 <!-- ============================== OS X alpha ============================== -->
 <h3 id="osx_alpha_checkers">OS X Alpha Checkers</h3>
 <table class="checkers">
 <colgroup><col class="namedescr"><col class="example"></colgroup>
 <thead><tr><td>Name, Description</td><td>Example</td></tr></thead>
 
 <tbody>
 <tr><td><div class="namedescr expandable"><span class="name">