[ASTMatchers] Add support of hasCondition for SwitchStmt.

Summary:
The switch statement could be added to the hasCondition matcher.

Example:
```
clang-query> match switchStmt(hasCondition(ignoringImpCasts(declRefExpr())))
```

Output:
```
Match #1:

Binding for "root":
SwitchStmt 0x2f9b528 </usr/local/google/home/etienneb/examples/enum.cc:35:3, line:38:3>
|-<<<NULL>>>
|-ImplicitCastExpr 0x2f9b510 <line:35:11> 'int' <IntegralCast>
| `-ImplicitCastExpr 0x2f9b4f8 <col:11> 'enum Color' <LValueToRValue>
|   `-DeclRefExpr 0x2f9b4d0 <col:11> 'enum Color' lvalue Var 0x2f9a118 'C' 'enum Color'
`-CompoundStmt 0x2f9b610 <col:14, line:38:3>
  |-CaseStmt 0x2f9b578 <line:36:3, col:22>
  | |-ImplicitCastExpr 0x2f9b638 <col:8> 'int' <IntegralCast>
  | | `-DeclRefExpr 0x2f9b550 <col:8> 'enum Size' EnumConstant 0x2f99e40 'Small' 'enum Size'
  | |-<<<NULL>>>
  | `-ReturnStmt 0x2f9b5d0 <col:15, col:22>
  |   `-IntegerLiteral 0x2f9b5b0 <col:22> 'int' 1
  `-DefaultStmt 0x2f9b5f0 <line:37:3, col:12>
    `-BreakStmt 0x2f9b5e8 <col:12>

1 match.
```

Reviewers: aaron.ballman, sbenza, klimek

Subscribers: klimek, cfe-commits

Differential Revision: http://reviews.llvm.org/D20767

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@271208 91177308-0d34-0410-b5e6-96231b3b80d8

Author: bergeret

docs/LibASTMatchersReference.html

@@ -3536,9 +3536,9 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 </pre></td></tr>
 
 
-<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1AbstractConditionalOperator.html">AbstractConditionalOperator</a>&gt;</td><td class="name" onclick="toggle('hasCondition4')"><a name="hasCondition4Anchor">hasCondition</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
-<tr><td colspan="4" class="doc" id="hasCondition4"><pre>Matches the condition expression of an if statement, for loop,
-or conditional operator.
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1AbstractConditionalOperator.html">AbstractConditionalOperator</a>&gt;</td><td class="name" onclick="toggle('hasCondition5')"><a name="hasCondition5Anchor">hasCondition</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="hasCondition5"><pre>Matches the condition expression of an if statement, for loop,
+switch statement or conditional operator.
 
 Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
   if (true) {}
@@ -4293,7 +4293,7 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1DoStmt.html">DoStmt</a>&gt;</td><td class="name" onclick="toggle('hasCondition3')"><a name="hasCondition3Anchor">hasCondition</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasCondition3"><pre>Matches the condition expression of an if statement, for loop,
-or conditional operator.
+switch statement or conditional operator.
 
 Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
   if (true) {}
@@ -4476,7 +4476,7 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1ForStmt.html">ForStmt</a>&gt;</td><td class="name" onclick="toggle('hasCondition1')"><a name="hasCondition1Anchor">hasCondition</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasCondition1"><pre>Matches the condition expression of an if statement, for loop,
-or conditional operator.
+switch statement or conditional operator.
 
 Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
   if (true) {}
@@ -4554,7 +4554,7 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1IfStmt.html">IfStmt</a>&gt;</td><td class="name" onclick="toggle('hasCondition0')"><a name="hasCondition0Anchor">hasCondition</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasCondition0"><pre>Matches the condition expression of an if statement, for loop,
-or conditional operator.
+switch statement or conditional operator.
 
 Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
   if (true) {}
@@ -5052,6 +5052,15 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 </pre></td></tr>
 
 
+<tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1SwitchStmt.html">SwitchStmt</a>&gt;</td><td class="name" onclick="toggle('hasCondition4')"><a name="hasCondition4Anchor">hasCondition</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
+<tr><td colspan="4" class="doc" id="hasCondition4"><pre>Matches the condition expression of an if statement, for loop,
+switch statement or conditional operator.
+
+Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
+  if (true) {}
+</pre></td></tr>
+
+
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1TagType.html">TagType</a>&gt;</td><td class="name" onclick="toggle('hasDeclaration4')"><a name="hasDeclaration4Anchor">hasDeclaration</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Decl.html">Decl</a>&gt;  InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasDeclaration4"><pre>Matches a node if the declaration associated with that node
 matches the given matcher.
@@ -5385,7 +5394,7 @@ <h2 id="traversal-matchers">AST Traversal Matchers</h2>
 
 <tr><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1WhileStmt.html">WhileStmt</a>&gt;</td><td class="name" onclick="toggle('hasCondition2')"><a name="hasCondition2Anchor">hasCondition</a></td><td>Matcher&lt;<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>&gt; InnerMatcher</td></tr>
 <tr><td colspan="4" class="doc" id="hasCondition2"><pre>Matches the condition expression of an if statement, for loop,
-or conditional operator.
+switch statement or conditional operator.
 
 Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
   if (true) {}

include/clang/ASTMatchers/ASTMatchers.h

@@ -3299,7 +3299,7 @@ AST_POLYMORPHIC_MATCHER(isConstexpr,
 }
 
 /// \brief Matches the condition expression of an if statement, for loop,
-/// or conditional operator.
+/// switch statement or conditional operator.
 ///
 /// Example matches true (matcher = hasCondition(cxxBoolLiteral(equals(true))))
 /// \code
@@ -3308,7 +3308,7 @@ AST_POLYMORPHIC_MATCHER(isConstexpr,
 AST_POLYMORPHIC_MATCHER_P(
     hasCondition,
     AST_POLYMORPHIC_SUPPORTED_TYPES(IfStmt, ForStmt, WhileStmt, DoStmt,
-                                    AbstractConditionalOperator),
+                                    SwitchStmt, AbstractConditionalOperator),
     internal::Matcher<Expr>, InnerMatcher) {
   const Expr *const Condition = Node.getCond();
   return (Condition != nullptr &&

unittests/ASTMatchers/ASTMatchersTraversalTest.cpp

@@ -958,6 +958,28 @@ TEST(Matcher, VisitsTemplateInstantiations) {
       callee(cxxMethodDecl(hasName("x"))))))));
 }
 
+TEST(Matcher, HasCondition) {
+  StatementMatcher IfStmt =
+    ifStmt(hasCondition(cxxBoolLiteral(equals(true))));
+  EXPECT_TRUE(matches("void x() { if (true) {} }", IfStmt));
+  EXPECT_TRUE(notMatches("void x() { if (false) {} }", IfStmt));
+
+  StatementMatcher ForStmt =
+    forStmt(hasCondition(cxxBoolLiteral(equals(true))));
+  EXPECT_TRUE(matches("void x() { for (;true;) {} }", ForStmt));
+  EXPECT_TRUE(notMatches("void x() { for (;false;) {} }", ForStmt));
+
+  StatementMatcher WhileStmt =
+    whileStmt(hasCondition(cxxBoolLiteral(equals(true))));
+  EXPECT_TRUE(matches("void x() { while (true) {} }", WhileStmt));
+  EXPECT_TRUE(notMatches("void x() { while (false) {} }", WhileStmt));
+
+  StatementMatcher SwitchStmt =
+    switchStmt(hasCondition(integerLiteral(equals(42))));
+  EXPECT_TRUE(matches("void x() { switch (42) {case 42:;} }", SwitchStmt));
+  EXPECT_TRUE(notMatches("void x() { switch (43) {case 43:;} }", SwitchStmt));
+}
+
 TEST(For, ForLoopInternals) {
   EXPECT_TRUE(matches("void f(){ int i; for (; i < 3 ; ); }",
                       forStmt(hasCondition(anything()))));