DiagnosticRenderer.cpp

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//===- DiagnosticRenderer.cpp - Diagnostic Pretty-Printing ----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
 
#include "clang/Frontend/DiagnosticRenderer.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/DiagnosticOptions.h"
#include "clang/Basic/LLVM.h"
#include "clang/Basic/SourceLocation.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/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <iterator>
#include <utility>
 
using namespace clang;
 
DiagnosticRenderer::DiagnosticRenderer(const LangOptions &LangOpts,
                                       DiagnosticOptions *DiagOpts)
    : LangOpts(LangOpts), DiagOpts(DiagOpts), LastLevel() {}
 
DiagnosticRenderer::~DiagnosticRenderer() = default;
 
namespace {
 
class FixitReceiver : public edit::EditsReceiver {
  SmallVectorImpl<FixItHint> &MergedFixits;
 
public:
  FixitReceiver(SmallVectorImpl<FixItHint> &MergedFixits)
      : MergedFixits(MergedFixits) {}
 
  void insert(SourceLocation loc, StringRef text) override {
    MergedFixits.push_back(FixItHint::CreateInsertion(loc, text));
  }
 
  void replace(CharSourceRange range, StringRef text) override {
    MergedFixits.push_back(FixItHint::CreateReplacement(range, text));
  }
};
 
} // namespace
 
static void mergeFixits(ArrayRef<FixItHint> FixItHints,
                        const SourceManager &SM, const LangOptions &LangOpts,
                        SmallVectorImpl<FixItHint> &MergedFixits) {
  edit::Commit commit(SM, LangOpts);
  for (const auto &Hint : FixItHints)
    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(FullSourceLoc Loc,
                                        DiagnosticsEngine::Level Level,
                                        StringRef Message,
                                        ArrayRef<CharSourceRange> Ranges,
                                        ArrayRef<FixItHint> FixItHints,
                                        DiagOrStoredDiag D) {
  assert(Loc.hasManager() || 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, D);
  else {
    // Get the ranges into a local array we can hack on.
    SmallVector<CharSourceRange, 20> MutableRanges(Ranges);
 
    SmallVector<FixItHint, 8> MergedFixits;
    if (!FixItHints.empty()) {
      mergeFixits(FixItHints, Loc.getManager(), LangOpts, MergedFixits);
      FixItHints = MergedFixits;
    }
 
    for (const auto &Hint : FixItHints)
      if (Hint.RemoveRange.isValid())
        MutableRanges.push_back(Hint.RemoveRange);
 
    FullSourceLoc UnexpandedLoc = Loc;
 
    // Find the ultimate expansion location for the diagnostic.
    Loc = Loc.getFileLoc();
 
    PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
 
    // First, if this diagnostic is not in the main file, print out the
    // "included from" lines.
    emitIncludeStack(Loc, PLoc, Level);
 
    // Next, emit the actual diagnostic message and caret.
    emitDiagnosticMessage(Loc, PLoc, Level, Message, Ranges, D);
    emitCaret(Loc, Level, MutableRanges, FixItHints);
 
    // If this location is within a macro, walk from UnexpandedLoc up to Loc
    // and produce a macro backtrace.
    if (UnexpandedLoc.isValid() && UnexpandedLoc.isMacroID()) {
      emitMacroExpansions(UnexpandedLoc, Level, MutableRanges, FixItHints);
    }
  }
 
  LastLoc = Loc;
  LastLevel = Level;
 
  endDiagnostic(D, Level);
}
 
void DiagnosticRenderer::emitStoredDiagnostic(StoredDiagnostic &Diag) {
  emitDiagnostic(Diag.getLocation(), Diag.getLevel(), Diag.getMessage(),
                 Diag.getRanges(), Diag.getFixIts(),
                 &Diag);
}
 
void DiagnosticRenderer::emitBasicNote(StringRef Message) {
  emitDiagnosticMessage(FullSourceLoc(), PresumedLoc(), DiagnosticsEngine::Note,
                        Message, {}, DiagOrStoredDiag());
}
 
/// 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(FullSourceLoc Loc, PresumedLoc PLoc,
                                          DiagnosticsEngine::Level Level) {
  FullSourceLoc IncludeLoc =
      PLoc.isInvalid() ? FullSourceLoc()
                       : FullSourceLoc(PLoc.getIncludeLoc(), Loc.getManager());
 
  // Skip redundant include stacks altogether.
  if (LastIncludeLoc == IncludeLoc)
    return;
 
  LastIncludeLoc = IncludeLoc;
 
  if (!DiagOpts->ShowNoteIncludeStack && Level == DiagnosticsEngine::Note)
    return;
 
  if (IncludeLoc.isValid())
    emitIncludeStackRecursively(IncludeLoc);
  else {
    emitModuleBuildStack(Loc.getManager());
    emitImportStack(Loc);
  }
}
 
/// Helper to recursively walk up the include stack and print each layer
/// on the way back down.
void DiagnosticRenderer::emitIncludeStackRecursively(FullSourceLoc Loc) {
  if (Loc.isInvalid()) {
    emitModuleBuildStack(Loc.getManager());
    return;
  }
 
  PresumedLoc PLoc = Loc.getPresumedLoc(DiagOpts->ShowPresumedLoc);
  if (PLoc.isInvalid())
    return;
 
  // If this source location was imported from a module, print the module
  // import stack rather than the
  // FIXME: We want submodule granularity here.
  std::pair<FullSourceLoc, StringRef> Imported = Loc.getModuleImportLoc();
  if (!Imported.second.empty()) {
    // This location was imported by a module. Emit the module import stack.
    emitImportStackRecursively(Imported.first, Imported.second);
    return;
  }
 
  // Emit the other include frames first.
  emitIncludeStackRecursively(
      FullSourceLoc(PLoc.getIncludeLoc(), Loc.getManager()));
 
  // Emit the inclusion text/note.