[ASTMatchers] Add isNoReturn() match narrower for FunctionDeclarations

[aaron.ballman]

You regenerate the HTML by running clang/docs/tools/dump_ast_matchers.py.

unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

1775

Spurious semicolon, which happens elsewhere in the tests as well -- please clean them all.

1834

For fun, I'd like to see a matchesC test for _Noreturn as well, just to be extra sure. :-)

[lebedev.ri]

• Added C tests
• Cleaned-up spurious semicolons
• Docs are still not regenerated, somehow that script results in a huge diff for me.

[aaron.ballman]

Aside from a documentation nit, this LGTM. However, you should wait to commit until after you can safely regenerate the AST matcher documentation. The issue there is that dump_ast_matchers.py was not updated after r318304. I believe @dblaikie was looking into the Python script, but I'm not certain how far he got with it.

include/clang/ASTMatchers/ASTMatchers.h

3579–3595

I don't think the documentation needs to list all of these -- it would be better to pick a representative few and just use those.

[lebedev.ri]

In D41455#963752, @aaron.ballman wrote:

Aside from a documentation nit, this LGTM. However, you should wait to commit until after you can safely regenerate the AST matcher documentation. The issue there is that dump_ast_matchers.py was not updated after r318304. I believe @dblaikie was looking into the Python script, but I'm not certain how far he got with it.

@dblaikie Hi! Did you get anywhere with the script update?
As far i'm concerned, all new ASTMatchers are stalled because of this...

[lebedev.ri]

• rebased
• finally updated docs
• found a new bug in doc generator https://bugs.llvm.org/show_bug.cgi?id=35989

Going to finally land this.

[lebedev.ri]

Update extra newline that prevented full documentation generation :/

[lebedev.ri]

Address review note: reduce amount of examples in documentation.

[aaron.ballman]

Great, looks good to commit. Thanks, Roman!

docs/LibASTMatchersReference.html

Given
   namespace n {
   inline namespace m {}
   }
 functionDecl(isInline()) will match ::f().
 namespaceDecl(isInline()) will match n::m.
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>&gt;</td><td class="name" onclick="toggle('isNoReturn0')"><a name="isNoReturn0Anchor">isNoReturn</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isNoReturn0"><pre>Matches FunctionDecls that have a noreturn attribute.
+
+Given
+  void nope();
+  [[noreturn]] void a0();
+  [[noreturn]] void a1() {}
+  __attribute__((noreturn)) void a2();
+  __attribute__((noreturn)) void a3() {}
+  struct b0 { [[noreturn]] b0(); };
+  struct b1 { [[noreturn]] b1() {} };
+  struct b2 { __attribute__((noreturn)) b2(); };
+  struct b3 { __attribute__((noreturn)) b3() {} };
+  struct c0 { [[noreturn]] int A(); };
+  struct c1 { [[noreturn]] int A() {} };
+  struct c2 { __attribute__((noreturn)) int A(); };
+  struct c3 { __attribute__((noreturn)) int A() {} };
+  struct d0 { [[noreturn]] static int A(); };
+  struct d1 { [[noreturn]] static int A() {} };
+  struct d2 { __attribute__((noreturn)) static int A(); };
+  struct d3 { __attribute__((noreturn)) static int A() {} };
+  extern "C" { void cNope(); }
+  extern "C" { __attribute__((noreturn)) void e0(); }
+  extern "C" { __attribute__((noreturn)) void e1() {} }
+  extern "C" { _Noreturn void e2(); }
+  extern "C" { _Noreturn void e3() {} }
+functionDecl(isNoReturn())
+  matches all of those except
+  void nope();
+  extern "C" { void cNope(); }
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1FunctionDecl.html">FunctionDecl</a>&gt;</td><td class="name" onclick="toggle('isNoThrow0')"><a name="isNoThrow0Anchor">isNoThrow</a></td><td></td></tr>
 <tr><td colspan="4" class="doc" id="isNoThrow0"><pre>Matches functions that have a non-throwing exception specification.
 
 Given:
   void f();
   void g() noexcept;
   void h() throw();
   void i() throw(int);

include/clang/ASTMatchers/ASTMatchers.h

 ///   matches void k(int x, int y, int z, ...);
 AST_POLYMORPHIC_MATCHER_P(parameterCountIs,
                           AST_POLYMORPHIC_SUPPORTED_TYPES(FunctionDecl,
                                                           FunctionProtoType),
                           unsigned, N) {
   return Node.getNumParams() == N;
 }
 
+/// \brief Matches \c FunctionDecls that have a noreturn attribute.
+///
+/// Given
+/// \code
+///   void nope();
+///   [[noreturn]] void a0();
+///   [[noreturn]] void a1() {}
+///   __attribute__((noreturn)) void a2();
+///   __attribute__((noreturn)) void a3() {}
+///   struct b0 { [[noreturn]] b0(); };
+///   struct b1 { [[noreturn]] b1() {} };
+///   struct b2 { __attribute__((noreturn)) b2(); };
+///   struct b3 { __attribute__((noreturn)) b3() {} };
+///   struct c0 { [[noreturn]] int A(); };
+///   struct c1 { [[noreturn]] int A() {} };
+///   struct c2 { __attribute__((noreturn)) int A(); };
+///   struct c3 { __attribute__((noreturn)) int A() {} };
+///   struct d0 { [[noreturn]] static int A(); };
+///   struct d1 { [[noreturn]] static int A() {} };
+///   struct d2 { __attribute__((noreturn)) static int A(); };
+///   struct d3 { __attribute__((noreturn)) static int A() {} };
+///   extern "C" { void cNope(); }
+///   extern "C" { __attribute__((noreturn)) void e0(); }
+///   extern "C" { __attribute__((noreturn)) void e1() {} }
+///   extern "C" { _Noreturn void e2(); }
+///   extern "C" { _Noreturn void e3() {} }
+/// \endcode
+/// functionDecl(isNoReturn())
+///   matches all of those except
+/// \code
+///   void nope();
+///   extern "C" { void cNope(); }
+/// \endcode
+AST_MATCHER(FunctionDecl, isNoReturn) {
+  return Node.isNoReturn();
+}
+
 /// \brief Matches the return type of a function declaration.
 ///
 /// Given:
 /// \code
 ///   class X { int f() { return 1; } };
 /// \endcode
 /// cxxMethodDecl(returns(asString("int")))
 ///   matches int f() { return 1; }

lib/ASTMatchers/Dynamic/Registry.cpp

RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(isInteger);
   REGISTER_MATCHER(isIntegral);
   REGISTER_MATCHER(isInTemplateInstantiation);
   REGISTER_MATCHER(isLambda);
   REGISTER_MATCHER(isListInitialization);
   REGISTER_MATCHER(isMemberInitializer);
   REGISTER_MATCHER(isMoveAssignmentOperator);
   REGISTER_MATCHER(isMoveConstructor);
+  REGISTER_MATCHER(isNoReturn);
   REGISTER_MATCHER(isNoThrow);
   REGISTER_MATCHER(isOverride);
   REGISTER_MATCHER(isPrivate);
   REGISTER_MATCHER(isProtected);
   REGISTER_MATCHER(isPublic);
   REGISTER_MATCHER(isPure);
   REGISTER_MATCHER(isSignedInteger);
   REGISTER_MATCHER(isStaticStorageClass);

unittests/ASTMatchers/ASTMatchersNarrowingTest.cpp

"template <typename T> class X {};"
       "template<> class X<int> {};",
     cxxRecordDecl(isExplicitTemplateSpecialization())));
   EXPECT_TRUE(matches(
     "template <typename T> void f(T t) {}"
       "template<> void f(int t) {}",
     functionDecl(isExplicitTemplateSpecialization())));
 }
 
+TEST(TypeMatching, MatchesNoReturn) {
+  EXPECT_TRUE(notMatches("void func();", functionDecl(isNoReturn())));
+  EXPECT_TRUE(notMatches("void func() {}", functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(notMatchesC("void func();", functionDecl(isNoReturn())));
+  EXPECT_TRUE(notMatchesC("void func() {}", functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(
+      notMatches("struct S { void func(); };", functionDecl(isNoReturn())));
+  EXPECT_TRUE(
+      notMatches("struct S { void func() {} };", functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(notMatches("struct S { static void func(); };",
+                         functionDecl(isNoReturn())));
+  EXPECT_TRUE(notMatches("struct S { static void func() {} };",
+                         functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(notMatches("struct S { S(); };", functionDecl(isNoReturn())));
+  EXPECT_TRUE(notMatches("struct S { S() {} };", functionDecl(isNoReturn())));
+
+  // ---
+
+  EXPECT_TRUE(matches("[[noreturn]] void func();", functionDecl(isNoReturn())));
+  EXPECT_TRUE(
+      matches("[[noreturn]] void func() {}", functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(matches("struct S { [[noreturn]] void func(); };",
+                      functionDecl(isNoReturn())));
+  EXPECT_TRUE(matches("struct S { [[noreturn]] void func() {} };",
+                      functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(matches("struct S { [[noreturn]] static void func(); };",
+                      functionDecl(isNoReturn())));
+  EXPECT_TRUE(matches("struct S { [[noreturn]] static void func() {} };",
+                      functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(
+      matches("struct S { [[noreturn]] S(); };", functionDecl(isNoReturn())));
+  EXPECT_TRUE(matches("struct S { [[noreturn]] S() {} };",
+                      functionDecl(isNoReturn())));
+
+  // ---
+
+  EXPECT_TRUE(matches("__attribute__((noreturn)) void func();",
+                      functionDecl(isNoReturn())));
+  EXPECT_TRUE(matches("__attribute__((noreturn)) void func() {}",
+                      functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(matches("struct S { __attribute__((noreturn)) void func(); };",
+                      functionDecl(isNoReturn())));
+  EXPECT_TRUE(matches("struct S { __attribute__((noreturn)) void func() {} };",
+                      functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(
+      matches("struct S { __attribute__((noreturn)) static void func(); };",
+              functionDecl(isNoReturn())));
+  EXPECT_TRUE(
+      matches("struct S { __attribute__((noreturn)) static void func() {} };",
+              functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(matches("struct S { __attribute__((noreturn)) S(); };",
+                      functionDecl(isNoReturn())));
+  EXPECT_TRUE(matches("struct S { __attribute__((noreturn)) S() {} };",
+                      functionDecl(isNoReturn())));
+
+  // ---
+
+  EXPECT_TRUE(matchesC("__attribute__((noreturn)) void func();",
+                      functionDecl(isNoReturn())));
+  EXPECT_TRUE(matchesC("__attribute__((noreturn)) void func() {}",
+                      functionDecl(isNoReturn())));
+
+  EXPECT_TRUE(matchesC("_Noreturn void func();",
+                      functionDecl(isNoReturn())));
+  EXPECT_TRUE(matchesC("_Noreturn void func() {}",
+                      functionDecl(isNoReturn())));
+}
+
 TEST(TypeMatching, MatchesBool) {
   EXPECT_TRUE(matches("struct S { bool func(); };",
                       cxxMethodDecl(returns(booleanType()))));
   EXPECT_TRUE(notMatches("struct S { void func(); };",
                          cxxMethodDecl(returns(booleanType()))));
 }
 
 TEST(TypeMatching, MatchesVoid) {