Fix crasher bug.

Due to not resetting the fake rparen data on the token when iterating
over annotated lines, we would pop the last element of the paren stack.

This patch fixes the underlying root cause, and makes the code more
robust against similar problems in the future:
- reset the first token when iterating on the same annotated lines due
  to preprocessor branches
- never pop the last element from the paren stack, so we do not crash,
  but rather incorrectly format
- add assert()s so we can figure out if our assumptions are violated

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@204140 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Format/ContinuationIndenter.cpp b/lib/Format/ContinuationIndenter.cpp
index 380532a47cc2b26b65840e97bbde871e4949aff8..cb4e4f53b2f3c0994aa03a774801b5b62d430d7a 100644 (file)
--- a/lib/Format/ContinuationIndenter.cpp
+++ b/lib/Format/ContinuationIndenter.cpp
@@ -217,8 +217,8 @@ unsigned ContinuationIndenter::addTokenToState(LineState &State, bool Newline,
                                                unsigned ExtraSpaces) {
   const FormatToken &Current = *State.NextToken;
 
-  if (State.Stack.size() == 0 ||
-      (Current.Type == TT_ImplicitStringLiteral &&
+  assert(!State.Stack.empty());
+  if ((Current.Type == TT_ImplicitStringLiteral &&
        (Current.Previous->Tok.getIdentifierInfo() == NULL ||
         Current.Previous->Tok.getIdentifierInfo()->getPPKeywordID() ==
             tok::pp_not_keyword))) {
@@ -628,8 +628,14 @@ unsigned ContinuationIndenter::moveStateToNextToken(LineState &State,
         //   SomeFunction(a, [] {
         //                     f();  // break
         //                   });
-        for (unsigned i = 0; i != Current.MatchingParen->FakeRParens; ++i)
+        for (unsigned i = 0; i != Current.MatchingParen->FakeRParens; ++i) {
+          assert(State.Stack.size() > 1);
+          if (State.Stack.size() == 1) {
+            // Do not pop the last element.
+            break;
+          }
           State.Stack.pop_back();
+        }
         bool IsObjCBlock =
             Previous &&
             (Previous->is(tok::caret) ||
@@ -709,6 +715,11 @@ unsigned ContinuationIndenter::moveStateToNextToken(LineState &State,
     // as they will have been removed early (see above).
     for (unsigned i = 0, e = Current.FakeRParens; i != e; ++i) {
       unsigned VariablePos = State.Stack.back().VariablePos;
+      assert(State.Stack.size() > 1);
+      if (State.Stack.size() == 1) {
+        // Do not pop the last element.
+        break;
+      }
       State.Stack.pop_back();
       State.Stack.back().VariablePos = VariablePos;
     }

diff --git a/lib/Format/TokenAnnotator.cpp b/lib/Format/TokenAnnotator.cpp
index 34aef99a7b296a55ea99530d4b3a14c1dca4a0f1..a91c847452155356e8aa0080e804f8595aca93e8 100644 (file)
--- a/lib/Format/TokenAnnotator.cpp
+++ b/lib/Format/TokenAnnotator.cpp
@@ -34,6 +34,7 @@ public:
       : Style(Style), Line(Line), CurrentToken(Line.First),
         KeywordVirtualFound(false), AutoFound(false), Ident_in(Ident_in) {
     Contexts.push_back(Context(tok::unknown, 1, /*IsExpression=*/false));
+    resetTokenMetadata(CurrentToken);
   }
 
 private:
@@ -571,6 +572,22 @@ public:
   }
 
 private:
+  void resetTokenMetadata(FormatToken *Token) {
+    if (Token == nullptr) return;
+
+    // Reset token type in case we have already looked at it and then
+    // recovered from an error (e.g. failure to find the matching >).
+    if (CurrentToken->Type != TT_LambdaLSquare &&
+        CurrentToken->Type != TT_FunctionLBrace &&
+        CurrentToken->Type != TT_ImplicitStringLiteral &&
+        CurrentToken->Type != TT_TrailingReturnArrow)
+      CurrentToken->Type = TT_Unknown;
+    if (CurrentToken->Role)
+      CurrentToken->Role.reset(NULL);
+    CurrentToken->FakeLParens.clear();
+    CurrentToken->FakeRParens = 0;
+  }
+
   void next() {
     if (CurrentToken != NULL) {
       determineTokenType(*CurrentToken);
@@ -581,19 +598,7 @@ private:
     if (CurrentToken != NULL)
       CurrentToken = CurrentToken->Next;
 
-    if (CurrentToken != NULL) {
-      // Reset token type in case we have already looked at it and then
-      // recovered from an error (e.g. failure to find the matching >).
-      if (CurrentToken->Type != TT_LambdaLSquare &&
-          CurrentToken->Type != TT_FunctionLBrace &&
-          CurrentToken->Type != TT_ImplicitStringLiteral &&
-          CurrentToken->Type != TT_TrailingReturnArrow)
-        CurrentToken->Type = TT_Unknown;
-      if (CurrentToken->Role)
-        CurrentToken->Role.reset(NULL);
-      CurrentToken->FakeLParens.clear();
-      CurrentToken->FakeRParens = 0;
-    }
+    resetTokenMetadata(CurrentToken);
   }
 
   /// \brief A struct to hold information valid in a specific context, e.g.

diff --git a/unittests/Format/FormatTest.cpp b/unittests/Format/FormatTest.cpp
index 5bd0822281e3b3145b8b0c7e37401a9b3c3b571b..b0324015cd6baab2207fbdc0391a5738ed6e14fb 100644 (file)
--- a/unittests/Format/FormatTest.cpp
+++ b/unittests/Format/FormatTest.cpp
@@ -8173,5 +8173,19 @@ TEST_F(FormatTest, SpacesInAngles) {
   verifyFormat("A<A<int>>();", Spaces);
 }
 
+TEST_F(FormatTest, HandleUnbalancedImplicitBracesAcrossPPBranches) {
+  std::string code = "#if A\n"
+                     "#if B\n"
+                     "a.\n"
+                     "#endif\n"
+                     "    a = 1;\n"
+                     "#else\n"
+                     "#endif\n"
+                     "#if C\n"
+                     "#else\n"
+                     "#endif\n";
+  EXPECT_EQ(code, format(code));
+}
+
 } // end namespace tooling
 } // end namespace clang