[clang-tidy] make readability-redundant-smartptr-get report get() usage in conditions

This patch extends clang-tidy's readability-redundant-smartptr-get to produce
warnings for previously unsupported cases:

```
std::unique_ptr<void> ptr;
if (ptr.get())
if (ptr.get() == NULL)
if (ptr.get() != NULL)
```

This is intended to fix https://llvm.org/bugs/show_bug.cgi?id=25804, a bug
report opened by @Eugene.Zelenko.

However, there still are cases not detected by the check. They can be found in
`void Negative()` function defined in
test/clang-tidy/readability-redundant-smartptr-get.cpp.

Reviewers: alexfh

Differential Revision: https://reviews.llvm.org/D24893

llvm-svn: 282386

2 files changed, 50 insertions, 14 deletions

diff --git a/clang-tools-extra/clang-tidy/readability/RedundantSmartptrGetCheck.cpp b/clang-tools-extra/clang-tidy/readability/RedundantSmartptrGetCheck.cpp
index 3d1c863843f..5aad5b5213b 100644
--- a/clang-tools-extra/clang-tidy/readability/RedundantSmartptrGetCheck.cpp
+++ b/clang-tools-extra/clang-tidy/readability/RedundantSmartptrGetCheck.cpp
@@ -60,21 +60,27 @@ void registerMatchersForGetEquals(MatchFinder *Finder,
   // might be on global namespace or found by ADL, might be a template, etc.
   // For now, lets keep a list of known standard types.
 
-  const auto IsAKnownSmartptr = recordDecl(
-      anyOf(hasName("::std::unique_ptr"), hasName("::std::shared_ptr")));
+  const auto IsAKnownSmartptr =
+      recordDecl(hasAnyName("::std::unique_ptr", "::std::shared_ptr"));
 
   // Matches against nullptr.
   Finder->addMatcher(
-      binaryOperator(
-          anyOf(hasOperatorName("=="), hasOperatorName("!=")),
-          hasEitherOperand(ignoringImpCasts(cxxNullPtrLiteralExpr())),
-          hasEitherOperand(callToGet(IsAKnownSmartptr))),
+      binaryOperator(anyOf(hasOperatorName("=="), hasOperatorName("!=")),
+                     hasEitherOperand(ignoringImpCasts(
+                         anyOf(cxxNullPtrLiteralExpr(), gnuNullExpr(),
+                               integerLiteral(equals(0))))),
+                     hasEitherOperand(callToGet(IsAKnownSmartptr))),
+      Callback);
+
+  // Matches against if(ptr.get())
+  Finder->addMatcher(
+      ifStmt(hasCondition(ignoringImpCasts(callToGet(IsAKnownSmartptr)))),
       Callback);
-  // TODO: Catch ptr.get() == other_ptr.get()
-}
 
+  // FIXME: Match and fix if (l.get() == r.get()).
+}
 
-}  // namespace
+} // namespace
 
 void RedundantSmartptrGetCheck::registerMatchers(MatchFinder *Finder) {
   // Only register the matchers for C++; the functionality currently does not
@@ -102,10 +108,11 @@ bool allReturnTypesMatch(const MatchFinder::MatchResult &Result) {
       Result.Nodes.getNodeAs<Type>("getType")->getUnqualifiedDesugaredType();
   return OpArrowType == OpStarType && OpArrowType == GetType;
 }
-}  // namespace
+} // namespace
 
 void RedundantSmartptrGetCheck::check(const MatchFinder::MatchResult &Result) {
-  if (!allReturnTypesMatch(Result)) return;
+  if (!allReturnTypesMatch(Result))
+    return;
 
   bool IsPtrToPtr = Result.Nodes.getNodeAs<Decl>("ptr_to_ptr") != nullptr;
   bool IsMemberExpr = Result.Nodes.getNodeAs<Expr>("memberExpr") != nullptr;
diff --git a/clang-tools-extra/test/clang-tidy/readability-redundant-smartptr-get.cpp b/clang-tools-extra/test/clang-tidy/readability-redundant-smartptr-get.cpp
index 61a36f6dee3..985efc58e42 100644
--- a/clang-tools-extra/test/clang-tidy/readability-redundant-smartptr-get.cpp
+++ b/clang-tools-extra/test/clang-tidy/readability-redundant-smartptr-get.cpp
@@ -113,6 +113,37 @@ void Positive() {
   // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: redundant get() call
   // CHECK-MESSAGES: i = *PointerWithOverloadedGet().get();
   // CHECK-FIXES: i = *PointerWithOverloadedGet();
+
+  bb = std::unique_ptr<int>().get() == NULL;
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: redundant get() call
+  // CHECK-MESSAGES: bb = std::unique_ptr<int>().get() == NULL;
+  // CHECK-FIXES: bb = std::unique_ptr<int>() == NULL;
+  bb = ss->get() == NULL;
+  // CHECK-MESSAGES: :[[@LINE-1]]:8: warning: redundant get() call
+  // CHECK-MESSAGES: bb = ss->get() == NULL;
+  // CHECK-FIXES: bb = *ss == NULL;
+
+  std::unique_ptr<int> x, y;
+  if (x.get() == nullptr);
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: redundant get() call
+  // CHECK-MESSAGES: if (x.get() == nullptr);
+  // CHECK-FIXES: if (x == nullptr);
+  if (nullptr == y.get());
+  // CHECK-MESSAGES: :[[@LINE-1]]:18: warning: redundant get() call
+  // CHECK-MESSAGES: if (nullptr == y.get());
+  // CHECK-FIXES: if (nullptr == y);
+  if (x.get() == NULL);
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: redundant get() call
+  // CHECK-MESSAGES: if (x.get() == NULL);
+  // CHECK-FIXES: if (x == NULL);
+  if (NULL == x.get());
+  // CHECK-MESSAGES: :[[@LINE-1]]:15: warning: redundant get() call
+  // CHECK-MESSAGES: if (NULL == x.get());
+  // CHECK-FIXES: if (NULL == x);
+  if (x.get());
+  // CHECK-MESSAGES: :[[@LINE-1]]:7: warning: redundant get() call
+  // CHECK-MESSAGES: if (x.get());
+  // CHECK-FIXES: if (x);
 }
 
 void Negative() {
@@ -137,7 +168,5 @@ void Negative() {
   (*Fail2().get()).Do();
 
   int_ptr ip;
-  bool bb = std::unique_ptr<int>().get() == NULL;
-  bb = ip.get() == nullptr;
-  bb = u->get() == NULL;
+  bool bb = ip.get() == nullptr;
 }