Properly identify 'this' as range-based for container

    
The Loop-Convert transform was mistransforming loops using 'this' implicitly.
Fixed and added tests.

Fixes PR15411.

llvm-svn: 176436

2 files changed, 80 insertions, 4 deletions

diff --git a/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.cpp b/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.cpp
index ed3bfc71bec..1a700706f75 100644
--- a/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.cpp
+++ b/clang-tools-extra/cpp11-migrate/LoopConvert/LoopActions.cpp
@@ -871,9 +871,15 @@ StringRef LoopFixer::checkDeferralsAndRejections(ASTContext *Context,
     return "";
   }
 
-  StringRef ContainerString =
-      getStringFromRange(Context->getSourceManager(), Context->getLangOpts(),
-                         ContainerExpr->getSourceRange());
+  StringRef ContainerString;
+  if (isa<CXXThisExpr>(ContainerExpr->IgnoreParenImpCasts())) {
+    ContainerString = "this";
+  } else {
+    ContainerString = getStringFromRange(Context->getSourceManager(),
+                                         Context->getLangOpts(),
+                                         ContainerExpr->getSourceRange());
+  }
+
   // In case someone is using an evil macro, reject this change.
   if (ContainerString.empty())
     ++*RejectedChanges;
diff --git a/clang-tools-extra/test/cpp11-migrate/LoopConvert/iterator.cpp b/clang-tools-extra/test/cpp11-migrate/LoopConvert/iterator.cpp
index 24981edd3fc..a59a90fbfa1 100644
--- a/clang-tools-extra/test/cpp11-migrate/LoopConvert/iterator.cpp
+++ b/clang-tools-extra/test/cpp11-migrate/LoopConvert/iterator.cpp
@@ -1,6 +1,8 @@
 // RUN: grep -Ev "// *[A-Z-]+:" %s > %t.cpp
 // RUN: cpp11-migrate -loop-convert %t.cpp -- -I %S/Inputs
 // RUN: FileCheck -input-file=%t.cpp %s
+// RUN: cpp11-migrate -loop-convert %t.cpp -risk=risky -- -I %S/Inputs
+// RUN: FileCheck -check-prefix=RISKY -input-file=%t.cpp %s
 
 #include "structures.h"
 
@@ -99,5 +101,73 @@ void f() {
   }
   // CHECK: for ({{[a-zA-Z_ ]*&? ?}}[[VAR:[a-z_]+]] : intmap)
   // CHECK-NEXT: printf("intmap[%d] = %d", [[VAR]].first, [[VAR]].second);
-
 }
+
+// Tests to ensure that an implicit 'this' is picked up as the container.
+// If member calls are made to 'this' within the loop, the transform becomes
+// risky as these calls may affect state that affects the loop.
+class C {
+public:
+  typedef MutableVal *iterator;
+  typedef const MutableVal *const_iterator;
+
+  iterator begin();
+  iterator end();
+  const_iterator begin() const;
+  const_iterator end() const;
+
+  void doSomething();
+  void doSomething() const;
+
+  void doLoop() {
+    for (iterator I = begin(), E = end(); I != E; ++I) {
+      // CHECK: for (auto & elem : *this) {
+    }
+    for (iterator I = C::begin(), E = C::end(); I != E; ++I) {
+      // CHECK: for (auto & elem : *this) {
+    }
+    for (iterator I = begin(), E = end(); I != E; ++I) {
+      // CHECK: for (iterator I = begin(), E = end(); I != E; ++I) {
+      // RISKY: for (auto & elem : *this) {
+      doSomething();
+    }
+    for (iterator I = begin(); I != end(); ++I) {
+      // CHECK: for (auto & elem : *this) {
+    }
+    for (iterator I = begin(); I != end(); ++I) {
+      // CHECK: for (iterator I = begin(); I != end(); ++I) {
+      // RISKY: for (auto & elem : *this) {
+      doSomething();
+    }
+  }
+
+  void doLoop() const {
+    for (const_iterator I = begin(), E = end(); I != E; ++I) {
+      // CHECK: for (auto & elem : *this) {
+    }
+    for (const_iterator I = C::begin(), E = C::end(); I != E; ++I) {
+      // CHECK: for (auto & elem : *this) {
+    }
+    for (const_iterator I = begin(), E = end(); I != E; ++I) {
+      // CHECK: for (const_iterator I = begin(), E = end(); I != E; ++I) {
+      // RISKY: for (auto & elem : *this) {
+      doSomething();
+    }
+  }
+};
+
+class C2 {
+public:
+  typedef MutableVal *iterator;
+
+  iterator begin() const;
+  iterator end() const;
+
+  void doLoop() {
+    // The implicit 'this' will have an Implicit cast to const C2* wrapped
+    // around it. Make sure the replacement still happens.
+    for (iterator I = begin(), E = end(); I != E; ++I) {
+      // CHECK: for (auto & elem : *this) {
+    }
+  }
+};