Remove and replace DiagStatePoint tracking and lookup data structure.

Rather than storing a single flat list of SourceLocations where the diagnostic
state changes (in source order), we now store a separate list for each FileID
in which there is a diagnostic state transition. (State for other files is
built and cached lazily, on demand.) This has two consequences:

1) We can now sensibly support modules, and properly track the diagnostic state
for modular headers (this matters when, for instance, triggering instantiation
of a template defined within a module triggers diagnostics).

2) It's much faster than the old approach, since we can now just do a binary
search on the offsets within the FileID rather than needing to call
isBeforeInTranslationUnit to determine source order (which is surprisingly
slow). For some pathological (but real world) files, this reduces total
compilation time by more than 10%.

For now, the diagnostic state points for modules are loaded eagerly. It seems
feasible to defer this until diagnostic state information for one of the
module's files is needed, but that's not part of this patch.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@293123 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 79 insertions, 21 deletions

diff --git a/include/clang/Basic/Diagnostic.h b/include/clang/Basic/Diagnostic.h
index a1683324b7..ffce99bf9f 100644
--- a/include/clang/Basic/Diagnostic.h
+++ b/include/clang/Basic/Diagnostic.h
@@ -29,6 +29,7 @@
 #include <cassert>
 #include <cstdint>
 #include <list>
+#include <map>
 #include <memory>
 #include <string>
 #include <type_traits>
@@ -232,40 +233,97 @@ private:
   /// \brief Keeps and automatically disposes all DiagStates that we create.
   std::list<DiagState> DiagStates;
 
-  /// \brief Represents a point in source where the diagnostic state was
-  /// modified because of a pragma.
-  ///
-  /// 'Loc' can be null if the point represents the diagnostic state
-  /// modifications done through the command-line.
-  struct DiagStatePoint {
-    DiagState *State;
-    SourceLocation Loc;
-    DiagStatePoint(DiagState *State, SourceLocation Loc)
-      : State(State), Loc(Loc) { } 
+  /// A mapping from files to the diagnostic states for those files. Lazily
+  /// built on demand for files in which the diagnostic state has not changed.
+  class DiagStateMap {
+  public:
+    /// Add an initial diagnostic state.
+    void appendFirst(DiagState *State);
+    /// Add a new latest state point.
+    void append(SourceManager &SrcMgr, SourceLocation Loc, DiagState *State);
+    /// Look up the diagnostic state at a given source location.
+    DiagState *lookup(SourceManager &SrcMgr, SourceLocation Loc) const;
+    /// Determine whether this map is empty.
+    bool empty() const { return Files.empty(); }
+    /// Clear out this map.
+    void clear() {
+      Files.clear();
+      FirstDiagState = CurDiagState = nullptr;
+      CurDiagStateLoc = SourceLocation();
+    }
+
+    /// Grab the most-recently-added state point.
+    DiagState *getCurDiagState() const { return CurDiagState; }
+    /// Get the location at which a diagnostic state was last added.
+    SourceLocation getCurDiagStateLoc() const { return CurDiagStateLoc; }
+
+  private:
+    /// \brief Represents a point in source where the diagnostic state was
+    /// modified because of a pragma.
+    ///
+    /// 'Loc' can be null if the point represents the diagnostic state
+    /// modifications done through the command-line.
+    struct DiagStatePoint {
+      DiagState *State;
+      unsigned Offset;
+      DiagStatePoint(DiagState *State, unsigned Offset)
+        : State(State), Offset(Offset) { } 
+    };
+
+    /// Description of the diagnostic states and state transitions for a
+    /// particular FileID.
+    struct File {
+      /// The diagnostic state for the parent file. This is strictly redundant,
+      /// as looking up the DecomposedIncludedLoc for the FileID in the Files
+      /// map would give us this, but we cache it here for performance.
+      File *Parent = nullptr;
+      /// The offset of this file within its parent.
+      unsigned ParentOffset = 0;
+      /// Whether this file has any local (not imported from an AST file)
+      /// diagnostic state transitions.
+      bool HasLocalTransitions = false;
+      /// The points within the file where the state changes. There will always
+      /// be at least one of these (the state on entry to the file).
+      llvm::SmallVector<DiagStatePoint, 4> StateTransitions;
+
+      DiagState *lookup(unsigned Offset) const;
+    };
+
+    /// The diagnostic states for each file.
+    mutable std::map<FileID, File> Files;
+
+    /// The initial diagnostic state.
+    DiagState *FirstDiagState;
+    /// The current diagnostic state.
+    DiagState *CurDiagState;
+    /// The location at which the current diagnostic state was established.
+    SourceLocation CurDiagStateLoc;
+
+    /// Get the diagnostic state information for a file.
+    File *getFile(SourceManager &SrcMgr, FileID ID) const;
+
+    friend class ASTReader;
+    friend class ASTWriter;
   };
 
-  /// \brief A sorted vector of all DiagStatePoints representing changes in
-  /// diagnostic state due to diagnostic pragmas.
-  ///
-  /// The vector is always sorted according to the SourceLocation of the
-  /// DiagStatePoint.
-  typedef std::vector<DiagStatePoint> DiagStatePointsTy;
-  mutable DiagStatePointsTy DiagStatePoints;
+  DiagStateMap DiagStatesByLoc;
 
   /// \brief Keeps the DiagState that was active during each diagnostic 'push'
   /// so we can get back at it when we 'pop'.
   std::vector<DiagState *> DiagStateOnPushStack;
 
   DiagState *GetCurDiagState() const {
-    assert(!DiagStatePoints.empty());
-    return DiagStatePoints.back().State;
+    return DiagStatesByLoc.getCurDiagState();
   }
 
   void PushDiagStatePoint(DiagState *State, SourceLocation L);
 
   /// \brief Finds the DiagStatePoint that contains the diagnostic state of
   /// the given source location.
-  DiagStatePointsTy::iterator GetDiagStatePointForLoc(SourceLocation Loc) const;
+  DiagState *GetDiagStateForLoc(SourceLocation Loc) const {
+    return SourceMgr ? DiagStatesByLoc.lookup(*SourceMgr, Loc)
+                     : DiagStatesByLoc.getCurDiagState();
+  }
 
   /// \brief Sticky flag set to \c true when an error is emitted.
   bool ErrorOccurred;
@@ -372,7 +430,7 @@ public:
     return *SourceMgr;
   }
   void setSourceManager(SourceManager *SrcMgr) {
-    assert(DiagStatePoints.size() == 1 && DiagStatePoints[0].Loc.isInvalid() &&
+    assert(DiagStatesByLoc.empty() &&
            "Leftover diag state from a different SourceManager.");
     SourceMgr = SrcMgr;
   }