Add ObjC exception statement AST matchers

[kastiglione]

Summary

Add AST matchers for Objective-C @throw, @try, @catch and @finally.

[aaron.ballman]

LGTM!

docs/LibASTMatchersReference.html

 <tr><td colspan="4" class="doc" id="nullStmt0"><pre>Matches null statements.
 
   foo();;
 nullStmt()
   matches the second ';'
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('objcCatchStmt0')"><a name="objcCatchStmt0Anchor">objcCatchStmt</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCAtCatchStmt.html">ObjCAtCatchStmt</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="objcCatchStmt0"><pre>Matches Objective-C @catch statements.
+
+Example matches @catch
+  @try {}
+  @catch (...) {}
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('objcFinallyStmt0')"><a name="objcFinallyStmt0Anchor">objcFinallyStmt</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCAtFinallyStmt.html">ObjCAtFinallyStmt</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="objcFinallyStmt0"><pre>Matches Objective-C @finally statements.
+
+Example matches @finally
+  @try {}
+  @finally {}
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('objcMessageExpr0')"><a name="objcMessageExpr0Anchor">objcMessageExpr</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCMessageExpr.html">ObjCMessageExpr</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="objcMessageExpr0"><pre>Matches ObjectiveC Message invocation expressions.
 
 The innermost message send invokes the "alloc" class method on the
 NSString class, while the outermost message send invokes the
 "initWithString" instance method on the object returned from
 NSString's "alloc". This matcher should match both message sends.
   [[NSString alloc] initWithString:@"Hello"]
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('objcThrowStmt0')"><a name="objcThrowStmt0Anchor">objcThrowStmt</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCAtThrowStmt.html">ObjCAtThrowStmt</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="objcThrowStmt0"><pre>Matches Objective-C @try statements.
+
+Example matches @throw
+  @throw obj;
+</pre></td></tr>
+
+
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('objcTryStmt0')"><a name="objcTryStmt0Anchor">objcTryStmt</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ObjCAtTryStmt.html">ObjCAtTryStmt</a>&gt;...</td></tr>
+<tr><td colspan="4" class="doc" id="objcTryStmt0"><pre>Matches Objective-C @try statements.
+
+Example matches @try
+  @try {}
+  @catch (...) {}
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Stmt.html">Stmt</a>&gt;</td><td class="name" onclick="toggle('opaqueValueExpr0')"><a name="opaqueValueExpr0Anchor">opaqueValueExpr</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1OpaqueValueExpr.html">OpaqueValueExpr</a>&gt;...</td></tr>
 <tr><td colspan="4" class="doc" id="opaqueValueExpr0"><pre>Matches opaque value expressions. They are used as helpers
 to reference another expressions and can be met
 in BinaryConditionalOperators, for example.
 
 Example matches 'a'
   (a ?: c) + 42;
 </pre></td></tr>

include/clang/ASTMatchers/ASTMatchers.h

 ///   @interface Foo
 ///   @property BOOL enabled;
 ///   @end
 /// \endcode
 const internal::VariadicDynCastAllOfMatcher<
   Decl,
   ObjCPropertyDecl> objcPropertyDecl;
 
+/// \brief Matches Objective-C @try statements.
+///
+/// Example matches @throw
+/// \code
+///   @throw obj;
+/// \endcode
+const internal::VariadicDynCastAllOfMatcher<
+  Stmt,
+  ObjCAtThrowStmt> objcThrowStmt;
+
+/// \brief Matches Objective-C @try statements.
+///
+/// Example matches @try
+/// \code
+///   @try {}
+///   @catch (...) {}
+/// \endcode
+const internal::VariadicDynCastAllOfMatcher<
+  Stmt,
+  ObjCAtTryStmt> objcTryStmt;
+
+/// \brief Matches Objective-C @catch statements.
+///
+/// Example matches @catch
+/// \code
+///   @try {}
+///   @catch (...) {}
+/// \endcode
+const internal::VariadicDynCastAllOfMatcher<
+  Stmt,
+  ObjCAtCatchStmt> objcCatchStmt;
+
+/// \brief Matches Objective-C @finally statements.
+///
+/// Example matches @finally
+/// \code
+///   @try {}
+///   @finally {}
+/// \endcode
+const internal::VariadicDynCastAllOfMatcher<
+  Stmt,
+  ObjCAtFinallyStmt> objcFinallyStmt;
+
 /// \brief Matches expressions that introduce cleanups to be run at the end
 /// of the sub-expression's evaluation.
 ///
 /// Example matches std::string()
 /// \code
 ///   const std::string str = std::string();
 /// \endcode
 const internal::VariadicDynCastAllOfMatcher<

lib/ASTMatchers/Dynamic/Registry.cpp

RegistryMaps::RegistryMaps() {
   REGISTER_MATCHER(namespaceDecl);
   REGISTER_MATCHER(namesType);
   REGISTER_MATCHER(nestedNameSpecifier);
   REGISTER_MATCHER(nestedNameSpecifierLoc);
   REGISTER_MATCHER(nullPointerConstant);
   REGISTER_MATCHER(nullStmt);
   REGISTER_MATCHER(numSelectorArgs);
   REGISTER_MATCHER(ofClass);
+  REGISTER_MATCHER(objcCatchStmt);
   REGISTER_MATCHER(objcCategoryDecl);
   REGISTER_MATCHER(objcCategoryImplDecl);
+  REGISTER_MATCHER(objcFinallyStmt);
   REGISTER_MATCHER(objcImplementationDecl);
   REGISTER_MATCHER(objcInterfaceDecl);
   REGISTER_MATCHER(objcIvarDecl);
   REGISTER_MATCHER(objcMessageExpr);
   REGISTER_MATCHER(objcMethodDecl);
   REGISTER_MATCHER(objcObjectPointerType);
   REGISTER_MATCHER(objcPropertyDecl);
   REGISTER_MATCHER(objcProtocolDecl);
+  REGISTER_MATCHER(objcThrowStmt);
+  REGISTER_MATCHER(objcTryStmt);
   REGISTER_MATCHER(on);
   REGISTER_MATCHER(onImplicitObjectArgument);
   REGISTER_MATCHER(opaqueValueExpr);
   REGISTER_MATCHER(parameterCountIs);
   REGISTER_MATCHER(parenExpr);
   REGISTER_MATCHER(parenListExpr);
   REGISTER_MATCHER(parenType);
   REGISTER_MATCHER(parmVarDecl);

unittests/ASTMatchers/ASTMatchersNodeTest.cpp

TEST(ObjCDeclMatcher, CoreDecls) {
   EXPECT_TRUE(matchesObjC(
     ObjCString,
     objcIvarDecl(hasName("_ivar"))));
   EXPECT_TRUE(matchesObjC(
     ObjCString,
     objcPropertyDecl(hasName("enabled"))));
 }
 
+TEST(ObjCStmtMatcher, ExceptionStmts) {
+  std::string ObjCString =
+    "void f(id obj) {"
+    "  @try {"
+    "    @throw obj;"
+    "  } @catch (...) {"
+    "  } @finally {}"
+    "}";
+
+  EXPECT_TRUE(matchesObjC(
+    ObjCString,
+    objcTryStmt()));
+  EXPECT_TRUE(matchesObjC(
+    ObjCString,
+    objcThrowStmt()));
+  EXPECT_TRUE(matchesObjC(
+    ObjCString,
+    objcCatchStmt()));
+  EXPECT_TRUE(matchesObjC(
+    ObjCString,
+    objcFinallyStmt()));
+}
+
 } // namespace ast_matchers
 } // namespace clang