Clang: Make SourceLocation lazily calculate its fields

Trigger path, line, column and offset evaluation only if one
of them is accessed.

Change-Id: Ib2f8b06ece94a3b7424db28523b5796628865202
Reviewed-by: Marco Bubke <marco.bubke@qt.io>

6 files changed, 68 insertions, 59 deletions

diff --git a/src/tools/clangbackend/source/clangfollowsymbol.cpp b/src/tools/clangbackend/source/clangfollowsymbol.cpp
index f8d763ae5e..27e8fb61e9 100644
--- a/src/tools/clangbackend/source/clangfollowsymbol.cpp
+++ b/src/tools/clangbackend/source/clangfollowsymbol.cpp
@@ -112,7 +112,7 @@ FollowSymbolResult FollowSymbol::followSymbol(CXTranslationUnit tu,
     if (cursor.kind() == CXCursor_InclusionDirective) {
         CXFile file = clang_getIncludedFile(cursors[tokenIndex].cx());
         const ClangString filename(clang_getFileName(file));
-        const SourceLocation loc(tu, filename, 1, 1);
+        const SourceLocation loc(tu, clang_getLocation(tu, file, 1, 1));
         FollowSymbolResult result;
         result.range = SourceRangeContainer(SourceRange(loc, loc));
         // CLANG-UPGRADE-CHECK: Remove if we don't use empty generated ui_* headers anymore.
diff --git a/src/tools/clangbackend/source/clangtranslationunit.cpp b/src/tools/clangbackend/source/clangtranslationunit.cpp
index 6eebc8e203..cc848f89ab 100644
--- a/src/tools/clangbackend/source/clangtranslationunit.cpp
+++ b/src/tools/clangbackend/source/clangtranslationunit.cpp
@@ -154,14 +154,22 @@ DiagnosticSet TranslationUnit::diagnostics() const
 
 SourceLocation TranslationUnit::sourceLocationAt(uint line,uint column) const
 {
-    return SourceLocation(m_cxTranslationUnit, m_filePath, line, column);
+    return SourceLocation(m_cxTranslationUnit,
+                          clang_getLocation(m_cxTranslationUnit,
+                                            clang_getFile(m_cxTranslationUnit,
+                                                          m_filePath.constData()),
+                                            line, column));
 }
 
 SourceLocation TranslationUnit::sourceLocationAt(const Utf8String &filePath,
                                                  uint line,
                                                  uint column) const
 {
-    return SourceLocation(m_cxTranslationUnit, filePath, line, column);
+    return SourceLocation(m_cxTranslationUnit,
+                          clang_getLocation(m_cxTranslationUnit,
+                                            clang_getFile(m_cxTranslationUnit,
+                                                          filePath.constData()),
+                                            line, column));
 }
 
 SourceRange TranslationUnit::sourceRange(uint fromLine,
diff --git a/src/tools/clangbackend/source/skippedsourceranges.cpp b/src/tools/clangbackend/source/skippedsourceranges.cpp
index f15bd44668..2ce2f15acb 100644
--- a/src/tools/clangbackend/source/skippedsourceranges.cpp
+++ b/src/tools/clangbackend/source/skippedsourceranges.cpp
@@ -66,7 +66,11 @@ static SourceRange adaptedSourceRange(CXTranslationUnit cxTranslationUnit, const
 
     return SourceRange {
         range.start(),
-        SourceLocation(cxTranslationUnit, end.filePath(), end.line(), 1)
+        SourceLocation(cxTranslationUnit,
+                       clang_getLocation(cxTranslationUnit,
+                                         clang_getFile(cxTranslationUnit,
+                                                       end.filePath().constData()),
+                                         end.line(), 1))
     };
 }
 
diff --git a/src/tools/clangbackend/source/sourcelocation.cpp b/src/tools/clangbackend/source/sourcelocation.cpp
index 965bd25129..70bb0e16aa 100644
--- a/src/tools/clangbackend/source/sourcelocation.cpp
+++ b/src/tools/clangbackend/source/sourcelocation.cpp
@@ -40,93 +40,92 @@
 namespace ClangBackEnd {
 
 SourceLocation::SourceLocation()
-    : cxSourceLocation(clang_getNullLocation())
+    : m_cxSourceLocation(clang_getNullLocation())
 {
 }
 
 const Utf8String &SourceLocation::filePath() const
 {
-    if (isFilePathNormalized_)
-        return filePath_;
+    if (!m_isEvaluated)
+        evaluate();
 
-    isFilePathNormalized_ = true;
-    filePath_ = FilePath::fromNativeSeparators(filePath_);
+    if (m_isFilePathNormalized)
+        return m_filePath;
 
-    return filePath_;
+    m_isFilePathNormalized = true;
+    m_filePath = FilePath::fromNativeSeparators(m_filePath);
+
+    return m_filePath;
 }
 
 uint SourceLocation::line() const
 {
-    return line_;
+    if (!m_isEvaluated)
+        evaluate();
+    return m_line;
 }
 
 uint SourceLocation::column() const
 {
-    return column_;
+    if (!m_isEvaluated)
+        evaluate();
+    return m_column;
 }
 
 uint SourceLocation::offset() const
 {
-    return offset_;
+    if (!m_isEvaluated)
+        evaluate();
+    return m_offset;
 }
 
 SourceLocationContainer SourceLocation::toSourceLocationContainer() const
 {
-    return SourceLocationContainer(filePath(), line_, column_);
+    if (!m_isEvaluated)
+        evaluate();
+    return SourceLocationContainer(filePath(), m_line, m_column);
 }
 
-SourceLocation::SourceLocation(CXTranslationUnit cxTranslationUnit,
-                               CXSourceLocation cxSourceLocation)
-    : cxSourceLocation(cxSourceLocation)
-    , cxTranslationUnit(cxTranslationUnit)
+void SourceLocation::evaluate() const
 {
+    m_isEvaluated = true;
+
     CXFile cxFile;
 
-    clang_getFileLocation(cxSourceLocation,
+    clang_getFileLocation(m_cxSourceLocation,
                           &cxFile,
-                          &line_,
-                          &column_,
-                          &offset_);
+                          &m_line,
+                          &m_column,
+                          &m_offset);
 
-    isFilePathNormalized_ = false;
+    m_isFilePathNormalized = false;
     if (!cxFile)
         return;
 
-    filePath_ = ClangString(clang_getFileName(cxFile));
-    if (column_ > 1) {
-        const uint lineStart = offset_ + 1 - column_;
-        const char *contents = clang_getFileContents(cxTranslationUnit, cxFile, nullptr);
+    m_filePath = ClangString(clang_getFileName(cxFile));
+    if (m_column > 1) {
+        const uint lineStart = m_offset + 1 - m_column;
+        const char *contents = clang_getFileContents(m_cxTranslationUnit, cxFile, nullptr);
         if (!contents)
             return;
         // (1) column in SourceLocation is the actual column shown by CppEditor.
         // (2) column in Clang is the utf8 byte offset from the beginning of the line.
         // Here we convert column from (2) to (1).
-        column_ = static_cast<uint>(QString::fromUtf8(&contents[lineStart],
-                                                      static_cast<int>(column_) - 1).size()) + 1;
+        m_column = static_cast<uint>(QString::fromUtf8(&contents[lineStart],
+                                                       static_cast<int>(m_column) - 1).size()) + 1;
     }
 }
 
 SourceLocation::SourceLocation(CXTranslationUnit cxTranslationUnit,
-                               const Utf8String &filePath,
-                               uint line,
-                               uint column)
-    : cxSourceLocation(clang_getLocation(cxTranslationUnit,
-                                         clang_getFile(cxTranslationUnit,
-                                                       filePath.constData()),
-                                         line,
-                                         column)),
-      cxTranslationUnit(cxTranslationUnit),
-      filePath_(filePath),
-      line_(line),
-      column_(column),
-      isFilePathNormalized_(true)
+                               CXSourceLocation cxSourceLocation)
+    : m_cxSourceLocation(cxSourceLocation)
+    , m_cxTranslationUnit(cxTranslationUnit)
 {
-    clang_getFileLocation(cxSourceLocation, 0, 0, 0, &offset_);
 }
 
 SourceLocation::operator CXSourceLocation() const
 {
-    return cxSourceLocation;
+    return m_cxSourceLocation;
 }
 
 std::ostream &operator<<(std::ostream &os, const SourceLocation &sourceLocation)
diff --git a/src/tools/clangbackend/source/sourcelocation.h b/src/tools/clangbackend/source/sourcelocation.h
index da0e68f973..63a600a2a6 100644
--- a/src/tools/clangbackend/source/sourcelocation.h
+++ b/src/tools/clangbackend/source/sourcelocation.h
@@ -41,7 +41,7 @@ class SourceLocation
 
     friend bool operator==(const SourceLocation &first, const SourceLocation &second)
     {
-        return clang_equalLocations(first.cxSourceLocation, second.cxSourceLocation);
+        return clang_equalLocations(first.m_cxSourceLocation, second.m_cxSourceLocation);
     }
     friend bool operator!=(const SourceLocation &first, const SourceLocation &second)
     {
@@ -51,10 +51,6 @@ class SourceLocation
 public:
     SourceLocation();
     SourceLocation(CXTranslationUnit cxTranslationUnit,
-                   const Utf8String &filePath,
-                   uint line,
-                   uint column);
-    SourceLocation(CXTranslationUnit cxTranslationUnit,
                    CXSourceLocation cxSourceLocation);
 
     const Utf8String &filePath() const;
@@ -64,20 +60,22 @@ public:
 
     SourceLocationContainer toSourceLocationContainer() const;
 
-    CXTranslationUnit tu() const { return cxTranslationUnit; }
-    CXSourceLocation cx() const { return cxSourceLocation; }
+    CXTranslationUnit tu() const { return m_cxTranslationUnit; }
+    CXSourceLocation cx() const { return m_cxSourceLocation; }
 
 private:
     operator CXSourceLocation() const;
+    void evaluate() const;
 
 private:
-   CXSourceLocation cxSourceLocation;
-   CXTranslationUnit cxTranslationUnit;
-   mutable Utf8String filePath_;
-   uint line_ = 0;
-   uint column_ = 0;
-   uint offset_ = 0;
-   mutable bool isFilePathNormalized_ = true;
+   CXSourceLocation m_cxSourceLocation;
+   CXTranslationUnit m_cxTranslationUnit;
+   mutable Utf8String m_filePath;
+   mutable uint m_line = 0;
+   mutable uint m_column = 0;
+   mutable uint m_offset = 0;
+   mutable bool m_isFilePathNormalized = true;
+   mutable bool m_isEvaluated = false;
 };
 
 std::ostream &operator<<(std::ostream &os, const SourceLocation &sourceLocation);
diff --git a/src/tools/clangbackend/source/sourcerange.cpp b/src/tools/clangbackend/source/sourcerange.cpp
index e3a7da6445..413ddd77fa 100644
--- a/src/tools/clangbackend/source/sourcerange.cpp
+++ b/src/tools/clangbackend/source/sourcerange.cpp
@@ -40,7 +40,7 @@ SourceRange::SourceRange()
 
 SourceRange::SourceRange(const SourceLocation &start, const SourceLocation &end)
     : cxSourceRange(clang_getRange(start, end)),
-      cxTranslationUnit(start.cxTranslationUnit)
+      cxTranslationUnit(start.m_cxTranslationUnit)
 {
 }