Clang: Filter out invalid diagnostic ranges

Apparently libclang might return invalid ranges.

Now we discard the invalid ranges. Since there is a diagnostic location
(in addition to ranges) the editor will still display an indication for
the user.

Task-number: QTCREATORBUG-15272
Change-Id: I351e136b9925a53fb2273a394e17873c5533798d
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@theqtcompany.com>

src/tools/clangbackend/ipcsource/diagnostic.cpp

@@ -106,13 +106,15 @@ DiagnosticSeverity Diagnostic::severity() const
 std::vector<SourceRange> Diagnostic::ranges() const
 {
     std::vector<SourceRange> ranges;
-
     const uint rangesCount = clang_getDiagnosticNumRanges(cxDiagnostic);
-
     ranges.reserve(rangesCount);
 
-    for (uint index = 0; index < rangesCount; ++index)
+    for (uint index = 0; index < rangesCount; ++index) {
+        const SourceRange sourceRange(clang_getDiagnosticRange(cxDiagnostic, index));
+
+        if (sourceRange.isValid())
             ranges.push_back(SourceRange(clang_getDiagnosticRange(cxDiagnostic, index)));
+    }
 
     return ranges;
 }

src/tools/clangbackend/ipcsource/sourcerange.cpp

@@ -39,6 +39,16 @@ SourceRange::SourceRange()
 {
 }
 
+bool SourceRange::isNull() const
+{
+    return clang_Range_isNull(cxSourceRange);
+}
+
+bool SourceRange::isValid() const
+{
+    return !isNull() && start().offset() < end().offset();
+}
+
 SourceLocation SourceRange::start() const
 {
     return SourceLocation(clang_getRangeStart(cxSourceRange));

src/tools/clangbackend/ipcsource/sourcerange.h

@@ -44,6 +44,10 @@ class SourceRange
 
 public:
     SourceRange();
+
+    bool isNull() const;
+    bool isValid() const;
+
     SourceLocation start() const;
     SourceLocation end() const;
 

tests/unit/unittest/data/diagnostic_source_range.cpp

@@ -7,3 +7,7 @@ int function(XXX i)
 {
     i + 20;
 }
+
+struct Foo {
+    someIdentifierLeadingToInvalidRange;
+};

tests/unit/unittest/sourcerangetest.cpp

@@ -85,9 +85,24 @@ protected:
                                     translationUnits};
     DiagnosticSet diagnosticSet{translationUnit.diagnostics()};
     Diagnostic diagnostic{diagnosticSet.front()};
+    Diagnostic diagnosticWithFilteredOutInvalidRange{diagnosticSet.at(1)};
     ::SourceRange sourceRange{diagnostic.ranges().front()};
 };
 
+TEST_F(SourceRange, IsNull)
+{
+    ::SourceRange sourceRange;
+
+    ASSERT_TRUE(sourceRange.isNull());
+}
+
+TEST_F(SourceRange, IsNotNull)
+{
+    ::SourceRange sourceRange = diagnostic.ranges()[0];
+
+    ASSERT_FALSE(sourceRange.isNull());
+}
+
 TEST_F(SourceRange, Size)
 {
     ASSERT_THAT(diagnostic.ranges().size(), 2);
@@ -108,4 +123,10 @@ TEST_F(SourceRange, End)
                                                       6u,
                                                       44u));
 }
+
+TEST_F(SourceRange, InvalidRangeIsFilteredOut)
+{
+    ASSERT_TRUE(diagnosticWithFilteredOutInvalidRange.ranges().empty());
+}
+
 }