path: root/lib/Frontend/DiagnosticRenderer.cpp

//===--- DiagnosticRenderer.cpp - Diagnostic Pretty-Printing --------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "clang/Frontend/DiagnosticRenderer.h"
#include "clang/Basic/DiagnosticOptions.h"
#include "clang/Basic/FileManager.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Edit/Commit.h"
#include "clang/Edit/EditedSource.h"
#include "clang/Edit/EditsReceiver.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace clang;

/// \brief Retrieve the name of the immediate macro expansion.
///
/// This routine starts from a source location, and finds the name of the macro
/// responsible for its immediate expansion. It looks through any intervening
/// macro argument expansions to compute this. It returns a StringRef which
/// refers to the SourceManager-owned buffer of the source where that macro
/// name is spelled. Thus, the result shouldn't out-live that SourceManager.
///
/// This differs from Lexer::getImmediateMacroName in that any macro argument
/// location will result in the topmost function macro that accepted it.
/// e.g.
/// \code
///   MAC1( MAC2(foo) )
/// \endcode
/// for location of 'foo' token, this function will return "MAC1" while
/// Lexer::getImmediateMacroName will return "MAC2".
static StringRef getImmediateMacroName(SourceLocation Loc,
                                       const SourceManager &SM,
                                       const LangOptions &LangOpts) {
   assert(Loc.isMacroID() && "Only reasonble to call this on macros");
   // Walk past macro argument expanions.
   while (SM.isMacroArgExpansion(Loc))
     Loc = SM.getImmediateExpansionRange(Loc).first;

   // If the macro's spelling has no FileID, then it's actually a token paste
   // or stringization (or similar) and not a macro at all.
   if (!SM.getFileEntryForID(SM.getFileID(SM.getSpellingLoc(Loc))))
     return StringRef();

   // Find the spelling location of the start of the non-argument expansion
   // range. This is where the macro name was spelled in order to begin
   // expanding this macro.
   Loc = SM.getSpellingLoc(SM.getImmediateExpansionRange(Loc).first);

   // Dig out the buffer where the macro name was spelled and the extents of the
   // name so that we can render it into the expansion note.
   std::pair<FileID, unsigned> ExpansionInfo = SM.getDecomposedLoc(Loc);
   unsigned MacroTokenLength = Lexer::MeasureTokenLength(Loc, SM, LangOpts);
   StringRef ExpansionBuffer = SM.getBufferData(ExpansionInfo.first);
   return ExpansionBuffer.substr(ExpansionInfo.second, MacroTokenLength);
}

DiagnosticRenderer::DiagnosticRenderer(const LangOptions &LangOpts,
                                       DiagnosticOptions *DiagOpts)
  : LangOpts(LangOpts), DiagOpts(DiagOpts), LastLevel() {}

DiagnosticRenderer::~DiagnosticRenderer() {}

namespace {

class FixitReceiver : public edit::EditsReceiver {
  SmallVectorImpl<FixItHint> &MergedFixits;

public:
  FixitReceiver(SmallVectorImpl<FixItHint> &MergedFixits)
    : MergedFixits(MergedFixits) { }
  virtual void insert(SourceLocation loc, StringRef text) {
    MergedFixits.push_back(FixItHint::CreateInsertion(loc, text));
  }
  virtual void replace(CharSourceRange range, StringRef text) {
    MergedFixits.push_back(FixItHint::CreateReplacement(range, text));
  }
};

}

static void mergeFixits(ArrayRef<FixItHint> FixItHints,
                        const SourceManager &SM, const LangOptions &LangOpts,
                        SmallVectorImpl<FixItHint> &MergedFixits) {
  edit::Commit commit(SM, LangOpts);
  for (ArrayRef<FixItHint>::const_iterator
         I = FixItHints.begin(), E = FixItHints.end(); I != E; ++I) {
    const FixItHint &Hint = *I;
    if (Hint.CodeToInsert.empty()) {
      if (Hint.InsertFromRange.isValid())
        commit.insertFromRange(Hint.RemoveRange.getBegin(),
                           Hint.InsertFromRange, /*afterToken=*/false,
                           Hint.BeforePreviousInsertions);
      else
        commit.remove(Hint.RemoveRange);
    } else {
      if (Hint.RemoveRange.isTokenRange() ||
          Hint.RemoveRange.getBegin() != Hint.RemoveRange.getEnd())
        commit.replace(Hint.RemoveRange, Hint.CodeToInsert);
      else
        commit.insert(Hint.RemoveRange.getBegin(), Hint.CodeToInsert,
                    /*afterToken=*/false, Hint.BeforePreviousInsertions);
    }
  }

  edit::EditedSource Editor(SM, LangOpts);
  if (Editor.commit(commit)) {
    FixitReceiver Rec(MergedFixits);
    Editor.applyRewrites(Rec);
  }
}

void DiagnosticRenderer::emitDiagnostic(SourceLocation Loc,
                                        DiagnosticsEngine::Level Level,
                                        StringRef Message,
                                        ArrayRef<CharSourceRange> Ranges,
                                        ArrayRef<FixItHint> FixItHints,
                                        const SourceManager *SM,
                                        DiagOrStoredDiag D) {
  assert(SM || Loc.isInvalid());

  beginDiagnostic(D, Level);

  if (!Loc.isValid())
    // If we have no source location, just emit the diagnostic message.
    emitDiagnosticMessage(Loc, PresumedLoc(), Level, Message, Ranges, SM, D);
  else {
    // Get the ranges into a local array we can hack on.
    SmallVector<CharSourceRange, 20> MutableRanges(Ranges.begin(),
                                                   Ranges.end());

    SmallVector<FixItHint, 8> MergedFixits;
    if (!FixItHints.empty()) {
      mergeFixits(FixItHints, *SM, LangOpts, MergedFixits);
      FixItHints = MergedFixits;
    }

    for (ArrayRef<FixItHint>::const_iterator I = FixItHints.begin(),
         E = FixItHints.end();
         I != E; ++I)
      if (I->RemoveRange.isValid())
        MutableRanges.push_back(I->RemoveRange);

    SourceLocation UnexpandedLoc = Loc;

    // Find the ultimate expansion location for the diagnostic.
    Loc = SM->getFileLoc(Loc);

    PresumedLoc PLoc = SM->getPresumedLoc(Loc, DiagOpts->ShowPresumedLoc);

    // First, if this diagnostic is not in the main file, print out the
    // "included from" lines.
    emitIncludeStack(Loc, PLoc, Level, *SM);

    // Next, emit the actual diagnostic message and caret.
    emitDiagnosticMessage(Loc, PLoc, Level, Message, Ranges, SM, D);
    emitCaret(Loc, Level, MutableRanges, FixItHints, *SM);

    // If this location is within a macro, walk from UnexpandedLoc up to Loc
    // and produce a macro backtrace.
    if (UnexpandedLoc.isValid() && UnexpandedLoc.isMacroID()) {
      unsigned MacroDepth = 0;
      emitMacroExpansions(UnexpandedLoc, Level, MutableRanges, FixItHints, *SM,
                          MacroDepth);
    }
  }

  LastLoc = Loc;
  LastLevel = Level;

  endDiagnostic(D, Level);
}


void DiagnosticRenderer::emitStoredDiagnostic(StoredDiagnostic &Diag) {
  emitDiagnostic(Diag.getLocation(), Diag.getLevel(), Diag.getMessage(),
                 Diag.getRanges(), Diag.getFixIts(),
                 Diag.getLocation().isValid() ? &Diag.getLocation().getManager()
                                              : 0,
                 &Diag);
}

/// \brief Prints an include stack when appropriate for a particular
/// diagnostic level and location.
///
/// This routine handles all the logic of suppressing particular include
/// stacks (such as those for notes) and duplicate include stacks when
/// repeated warnings occur within the same file. It also handles the logic
/// of customizing the formatting and display of the include stack.
///
/// \param Loc   The diagnostic location.
/// \param PLoc  The presumed location of the diagnostic location.
/// \param Level The diagnostic level of the message this stack pertains to.
void DiagnosticRenderer::emitIncludeStack(SourceLocation Loc,
                                          PresumedLoc PLoc,
                                          DiagnosticsEngine::Level Level,
                                          const SourceManager &SM) {
  SourceLocation IncludeLoc = PLoc.getIncludeLoc();

  // Skip redundant include stacks altogether.
  if (LastIncludeLoc == IncludeLoc)
    return;
  
  LastIncludeLoc = IncludeLoc;
  
  if (!DiagOpts->ShowNoteIncludeStack && Level == DiagnosticsEngine::Note)
    return;

  if (IncludeLoc.isValid())
    emitIncludeStackRecursively(IncludeLoc, SM);
  else {
    emitModuleBuildStack(SM);
    emitImportStack(Loc, SM);
  }
}

/// \brief He