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<h1>Implicit Checkers</h1>
Even though the implicit checkers do not produce any warnings, they are used to
support the analyzer core and model known APIs. See also
<a href = "available_checks.html">Default Checkers</a>
and <a href = "alpha_checks.html">Experimental (Alpha) Checkers</a>.
<ul>
<li><a href="#core_implicit_checkers">Core Implicit Checkers</a></li>
<li><a href="#osx_implicit_checkers">OS X Implicit Checkers</a></li>
</ul>

<!-- =========================== core implicit =========================== -->
<h3 id="core_implicit_checkers">Core Implicit 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">
core.DynamicTypePropagation</span><span class="lang">
(C++, ObjC)</span><div class="descr">
Generate dynamic type information.</div></div></td>
<td><div class="exampleContainer expandable">
<div class="example"><pre>
// C++
class A {
public:
  A(int x) {}
  virtual int foo();
};

class B: public A {
public:
  B()
  :A(foo())
  // DynamicTypeInfo for 'this' rigion will wrap type 'A'
  // unless the base constructor call expression is processed
  {}
  virtual int foo();
};
</pre></div><div class="separator"></div>
<div class="example"><pre>
// Objective-C
@interface MyClass : NSObject {}
@end

@implementation MyClass
+ (void)foo {
  MyClass *x = [[self alloc] init];
  // DynamicTypeInfo from a cast: from 'id' to 'MyClass *'
}
@end

void test() {
  MyClass *x = [MyClass alloc];
  // DynamicTypeInfo from a call to alloc:
  // from 'id' to 'MyClass *'
}
</pre></div></div></td></tr>


<tr><td><div class="namedescr expandable"><span class="name">
core.builtin.BuiltinFunctions</span><span class="lang">
(C)</span><div class="descr">
Evaluate compiler builtin functions (e.g., <code>alloca()</code>)</div></div></td>
<td><div class="exampleContainer expandable">
<div class="example"><pre>
void test(int x) {
  int *p = (int *)__builtin_alloca(8);
    // evaluates to AllocaRegion

  if(__builtin_expect(x > 10, 0)) // evaluates to 'x > 10'
    x = 0;
}
</pre></div></div></td></tr>


<tr><td><div class="namedescr expandable"><span class="name">
core.builtin.NoReturnFunctions</span><span class="lang">
(C, ObjC)</span><div class="descr">
Evaluate "panic" functions that are known to not return to the caller.</div></div></td>
<td><div class="exampleContainer expandable">
<div class="example"><pre>
// C
void test() {
  panic(); // generate sink
}
</pre></div><div class="separator"></div>
<div class="example"><pre>
// Objective-C
@interface MyObj : NSObject {}
- (void)foo;
@end

@implementation MyObj
- (void)foo {
  [[NSAssertionHandler currentHandler] handleFailureInMethod:_cmd
                                       object:self
                                       file:(@"somefile.m")
                                       lineNumber:1
                                       description:(@"some text")];
    // generate sink
}
@end
</pre></div></div></td></tr>

</tbody></table>

<!-- =========================== OS X implicit =========================== -->
<h3 id="osx_implicit_checkers">OS X Implicit 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">
osx.cocoa.Loops</span><span class="lang">
(ObjC)</span><div class="descr">
Improved modeling of loops using Cocoa collection types.</div></div></td>
<td><div class="exampleContainer expandable">
<div class="example"><pre>
void test() {
  id x;
  for (x in [NSArray testObject]) {
    // assume the value of 'x' is non-nil
  }
}
</pre></div></div></td></tr>


<tr><td><div class="namedescr expandable"><span class="name">
osx.cocoa.NonNilReturnValue</span><span class="lang">
(ObjC)</span><div class="descr">
Model the APIs that are guaranteed to return a non-nil value.</div></div></td>
<td><div class="exampleContainer expandable">
<div class="example"><pre>
void test(NSArray *A) {
  id subscriptObj = A[1]; // assume the value is non-nil
}
</pre></div></div></td></tr>

</tbody></table>

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llvm/clang/www/analyzer/implicit_checks.html
