Add basic fix-its to SMDiagnostic.

Like Clang's FixItHint, SMFixIt represents an insertion, replacement, or
removal of source text. One or more fix-its can be emitted as part of
a diagnostic, and will be printed below the source range line to show the
user how they can fix their code.

Currently, the only client of SMFixIt is clang-tblgen; thus, the tests for
this behavior live in clang/test/TableGen/tg-fixits.td. If/when SMFixIt is
adopted within LLVM itself, those tests should be moved to the LLVM suite.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@172086 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 59 insertions, 11 deletions

diff --git a/include/llvm/Support/SourceMgr.h b/include/llvm/Support/SourceMgr.h
index dddb013..02abf92 100644
--- a/include/llvm/Support/SourceMgr.h
+++ b/include/llvm/Support/SourceMgr.h
@@ -17,6 +17,8 @@
 #define LLVM_SUPPORT_SOURCEMGR_H
 
 #include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/Support/SMLoc.h"
 #include <string>
 
@@ -24,6 +26,7 @@ namespace llvm {
   class MemoryBuffer;
   class SourceMgr;
   class SMDiagnostic;
+  class SMFixIt;
   class Twine;
   class raw_ostream;
 
@@ -143,6 +146,7 @@ public:
   /// the default error handler is used.
   void PrintMessage(SMLoc Loc, DiagKind Kind, const Twine &Msg,
                     ArrayRef<SMRange> Ranges = ArrayRef<SMRange>(),
+                    ArrayRef<SMFixIt> FixIts = ArrayRef<SMFixIt>(),
                     bool ShowColors = true) const;
 
 
@@ -152,7 +156,8 @@ public:
   /// @param Msg If non-null, the kind of message (e.g., "error") which is
   /// prefixed to the message.
   SMDiagnostic GetMessage(SMLoc Loc, DiagKind Kind, const Twine &Msg, 
-                          ArrayRef<SMRange> Ranges = ArrayRef<SMRange>()) const;
+                          ArrayRef<SMRange> Ranges = ArrayRef<SMRange>(),
+                          ArrayRef<SMFixIt> FixIts = ArrayRef<SMFixIt>()) const;
 
   /// PrintIncludeStack - Prints the names of included files and the line of the
   /// file they were included from.  A diagnostic handler can use this before
@@ -164,6 +169,38 @@ public:
 };
 
 
+/// Represents a single fixit, a replacement of one range of text with another.
+class SMFixIt {
+  SMRange Range;
+
+  std::string Text;
+
+public:
+  // FIXME: Twine.str() is not very efficient.
+  SMFixIt(SMLoc Loc, const Twine &Insertion)
+    : Range(Loc, Loc), Text(Insertion.str()) {
+    assert(Loc.isValid());
+  }
+
+  // FIXME: Twine.str() is not very efficient.
+  SMFixIt(SMRange R, const Twine &Replacement)
+    : Range(R), Text(Replacement.str()) {
+    assert(R.isValid());
+  }
+
+  StringRef getText() const { return Text; }
+  SMRange getRange() const { return Range; }
+
+  bool operator<(const SMFixIt &Other) const {
+    if (Range.Start.getPointer() != Other.Range.Start.getPointer())
+      return Range.Start.getPointer() < Other.Range.Start.getPointer();
+    if (Range.End.getPointer() != Other.Range.End.getPointer())
+      return Range.End.getPointer() < Other.Range.End.getPointer();
+    return Text < Other.Text;
+  }
+};
+
+
 /// SMDiagnostic - Instances of this class encapsulate one diagnostic report,
 /// allowing printing to a raw_ostream as a caret diagnostic.
 class SMDiagnostic {
@@ -174,35 +211,46 @@ class SMDiagnostic {
   SourceMgr::DiagKind Kind;
   std::string Message, LineContents;
   std::vector<std::pair<unsigned, unsigned> > Ranges;
+  SmallVector<SMFixIt, 4> FixIts;
 
 public:
   // Null diagnostic.
   SMDiagnostic()
     : SM(0), LineNo(0), ColumnNo(0), Kind(SourceMgr::DK_Error) {}
   // Diagnostic with no location (e.g. file not found, command line arg error).
-  SMDiagnostic(const std::string &filename, SourceMgr::DiagKind Knd,
-               const std::string &Msg)
+  SMDiagnostic(StringRef filename, SourceMgr::DiagKind Knd, StringRef Msg)
     : SM(0), Filename(filename), LineNo(-1), ColumnNo(-1), Kind(Knd),
       Message(Msg) {}
   
   // Diagnostic with a location.
-  SMDiagnostic(const SourceMgr &sm, SMLoc L, const std::string &FN,
+  SMDiagnostic(const SourceMgr &sm, SMLoc L, StringRef FN,
                int Line, int Col, SourceMgr::DiagKind Kind,
-               const std::string &Msg, const std::string &LineStr,
-               ArrayRef<std::pair<unsigned,unsigned> > Ranges);
+               StringRef Msg, StringRef LineStr,
+               ArrayRef<std::pair<unsigned,unsigned> > Ranges,
+               ArrayRef<SMFixIt> FixIts = ArrayRef<SMFixIt>());
 
   const SourceMgr *getSourceMgr() const { return SM; }
   SMLoc getLoc() const { return Loc; }
-  const std::string &getFilename() const { return Filename; }
+  StringRef getFilename() const { return Filename; }
   int getLineNo() const { return LineNo; }
   int getColumnNo() const { return ColumnNo; }
   SourceMgr::DiagKind getKind() const { return Kind; }
-  const std::string &getMessage() const { return Message; }
-  const std::string &getLineContents() const { return LineContents; }
-  const std::vector<std::pair<unsigned, unsigned> > &getRanges() const {
+  StringRef getMessage() const { return Message; }
+  StringRef getLineContents() const { return LineContents; }
+  ArrayRef<std::pair<unsigned, unsigned> > getRanges() const {
     return Ranges;
   }
-  void print(const char *ProgName, raw_ostream &S, bool ShowColors = true) const;
+
+  void addFixIt(const SMFixIt &Hint) {
+    FixIts.push_back(Hint);
+  }
+
+  ArrayRef<SMFixIt> getFixIts() const {
+    return FixIts;
+  }
+
+  void print(const char *ProgName, raw_ostream &S,
+             bool ShowColors = true) const;
 };
 
 }  // end llvm namespace