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      1 //===--- DiagnosticRenderer.cpp - Diagnostic Pretty-Printing --------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #include "clang/Frontend/DiagnosticRenderer.h"
     11 #include "clang/Basic/DiagnosticOptions.h"
     12 #include "clang/Basic/FileManager.h"
     13 #include "clang/Basic/SourceManager.h"
     14 #include "clang/Edit/Commit.h"
     15 #include "clang/Edit/EditedSource.h"
     16 #include "clang/Edit/EditsReceiver.h"
     17 #include "clang/Lex/Lexer.h"
     18 #include "llvm/ADT/SmallSet.h"
     19 #include "llvm/ADT/SmallString.h"
     20 #include "llvm/Support/ErrorHandling.h"
     21 #include "llvm/Support/MemoryBuffer.h"
     22 #include "llvm/Support/raw_ostream.h"
     23 #include <algorithm>
     24 using namespace clang;
     25 
     26 /// \brief Retrieve the name of the immediate macro expansion.
     27 ///
     28 /// This routine starts from a source location, and finds the name of the macro
     29 /// responsible for its immediate expansion. It looks through any intervening
     30 /// macro argument expansions to compute this. It returns a StringRef which
     31 /// refers to the SourceManager-owned buffer of the source where that macro
     32 /// name is spelled. Thus, the result shouldn't out-live that SourceManager.
     33 ///
     34 /// This differs from Lexer::getImmediateMacroName in that any macro argument
     35 /// location will result in the topmost function macro that accepted it.
     36 /// e.g.
     37 /// \code
     38 ///   MAC1( MAC2(foo) )
     39 /// \endcode
     40 /// for location of 'foo' token, this function will return "MAC1" while
     41 /// Lexer::getImmediateMacroName will return "MAC2".
     42 static StringRef getImmediateMacroName(SourceLocation Loc,
     43                                        const SourceManager &SM,
     44                                        const LangOptions &LangOpts) {
     45    assert(Loc.isMacroID() && "Only reasonble to call this on macros");
     46    // Walk past macro argument expanions.
     47    while (SM.isMacroArgExpansion(Loc))
     48      Loc = SM.getImmediateExpansionRange(Loc).first;
     49 
     50    // If the macro's spelling has no FileID, then it's actually a token paste
     51    // or stringization (or similar) and not a macro at all.
     52    if (!SM.getFileEntryForID(SM.getFileID(SM.getSpellingLoc(Loc))))
     53      return StringRef();
     54 
     55    // Find the spelling location of the start of the non-argument expansion
     56    // range. This is where the macro name was spelled in order to begin
     57    // expanding this macro.
     58    Loc = SM.getSpellingLoc(SM.getImmediateExpansionRange(Loc).first);
     59 
     60    // Dig out the buffer where the macro name was spelled and the extents of the
     61    // name so that we can render it into the expansion note.
     62    std::pair<FileID, unsigned> ExpansionInfo = SM.getDecomposedLoc(Loc);
     63    unsigned MacroTokenLength = Lexer::MeasureTokenLength(Loc, SM, LangOpts);
     64    StringRef ExpansionBuffer = SM.getBufferData(ExpansionInfo.first);
     65    return ExpansionBuffer.substr(ExpansionInfo.second, MacroTokenLength);
     66 }
     67 
     68 DiagnosticRenderer::DiagnosticRenderer(const LangOptions &LangOpts,
     69                                        DiagnosticOptions *DiagOpts)
     70   : LangOpts(LangOpts), DiagOpts(DiagOpts), LastLevel() {}
     71 
     72 DiagnosticRenderer::~DiagnosticRenderer() {}
     73 
     74 namespace {
     75 
     76 class FixitReceiver : public edit::EditsReceiver {
     77   SmallVectorImpl<FixItHint> &MergedFixits;
     78 
     79 public:
     80   FixitReceiver(SmallVectorImpl<FixItHint> &MergedFixits)
     81     : MergedFixits(MergedFixits) { }
     82   virtual void insert(SourceLocation loc, StringRef text) {
     83     MergedFixits.push_back(FixItHint::CreateInsertion(loc, text));
     84   }
     85   virtual void replace(CharSourceRange range, StringRef text) {
     86     MergedFixits.push_back(FixItHint::CreateReplacement(range, text));
     87   }
     88 };
     89 
     90 }
     91 
     92 static void mergeFixits(ArrayRef<FixItHint> FixItHints,
     93                         const SourceManager &SM, const LangOptions &LangOpts,
     94                         SmallVectorImpl<FixItHint> &MergedFixits) {
     95   edit::Commit commit(SM, LangOpts);
     96   for (ArrayRef<FixItHint>::const_iterator
     97          I = FixItHints.begin(), E = FixItHints.end(); I != E; ++I) {
     98     const FixItHint &Hint = *I;
     99     if (Hint.CodeToInsert.empty()) {
    100       if (Hint.InsertFromRange.isValid())
    101         commit.insertFromRange(Hint.RemoveRange.getBegin(),
    102                            Hint.InsertFromRange, /*afterToken=*/false,
    103                            Hint.BeforePreviousInsertions);
    104       else
    105         commit.remove(Hint.RemoveRange);
    106     } else {
    107       if (Hint.RemoveRange.isTokenRange() ||
    108           Hint.RemoveRange.getBegin() != Hint.RemoveRange.getEnd())
    109         commit.replace(Hint.RemoveRange, Hint.CodeToInsert);
    110       else
    111         commit.insert(Hint.RemoveRange.getBegin(), Hint.CodeToInsert,
    112                     /*afterToken=*/false, Hint.BeforePreviousInsertions);
    113     }
    114   }
    115 
    116   edit::EditedSource Editor(SM, LangOpts);
    117   if (Editor.commit(commit)) {
    118     FixitReceiver Rec(MergedFixits);
    119     Editor.applyRewrites(Rec);
    120   }
    121 }
    122 
    123 void DiagnosticRenderer::emitDiagnostic(SourceLocation Loc,
    124                                         DiagnosticsEngine::Level Level,
    125                                         StringRef Message,
    126                                         ArrayRef<CharSourceRange> Ranges,
    127                                         ArrayRef<FixItHint> FixItHints,
    128                                         const SourceManager *SM,
    129                                         DiagOrStoredDiag D) {
    130   assert(SM || Loc.isInvalid());
    131 
    132   beginDiagnostic(D, Level);
    133 
    134   if (!Loc.isValid())
    135     // If we have no source location, just emit the diagnostic message.
    136     emitDiagnosticMessage(Loc, PresumedLoc(), Level, Message, Ranges, SM, D);
    137   else {
    138     // Get the ranges into a local array we can hack on.
    139     SmallVector<CharSourceRange, 20> MutableRanges(Ranges.begin(),
    140                                                    Ranges.end());
    141 
    142     SmallVector<FixItHint, 8> MergedFixits;
    143     if (!FixItHints.empty()) {
    144       mergeFixits(FixItHints, *SM, LangOpts, MergedFixits);
    145       FixItHints = MergedFixits;
    146     }
    147 
    148     for (ArrayRef<FixItHint>::const_iterator I = FixItHints.begin(),
    149          E = FixItHints.end();
    150          I != E; ++I)
    151       if (I->RemoveRange.isValid())
    152         MutableRanges.push_back(I->RemoveRange);
    153 
    154     SourceLocation UnexpandedLoc = Loc;
    155 
    156     // Find the ultimate expansion location for the diagnostic.
    157     Loc = SM->getFileLoc(Loc);
    158 
    159     PresumedLoc PLoc = SM->getPresumedLoc(Loc, DiagOpts->ShowPresumedLoc);
    160 
    161     // First, if this diagnostic is not in the main file, print out the
    162     // "included from" lines.
    163     emitIncludeStack(Loc, PLoc, Level, *SM);
    164 
    165     // Next, emit the actual diagnostic message and caret.
    166     emitDiagnosticMessage(Loc, PLoc, Level, Message, Ranges, SM, D);
    167     emitCaret(Loc, Level, MutableRanges, FixItHints, *SM);
    168 
    169     // If this location is within a macro, walk from UnexpandedLoc up to Loc
    170     // and produce a macro backtrace.
    171     if (UnexpandedLoc.isValid() && UnexpandedLoc.isMacroID()) {
    172       unsigned MacroDepth = 0;
    173       emitMacroExpansions(UnexpandedLoc, Level, MutableRanges, FixItHints, *SM,
    174                           MacroDepth);
    175     }
    176   }
    177 
    178   LastLoc = Loc;
    179   LastLevel = Level;
    180 
    181   endDiagnostic(D, Level);
    182 }
    183 
    184 
    185 void DiagnosticRenderer::emitStoredDiagnostic(StoredDiagnostic &Diag) {
    186   emitDiagnostic(Diag.getLocation(), Diag.getLevel(), Diag.getMessage(),
    187                  Diag.getRanges(), Diag.getFixIts(),
    188                  Diag.getLocation().isValid() ? &Diag.getLocation().getManager()
    189                                               : 0,
    190                  &Diag);
    191 }
    192 
    193 /// \brief Prints an include stack when appropriate for a particular
    194 /// diagnostic level and location.
    195 ///
    196 /// This routine handles all the logic of suppressing particular include
    197 /// stacks (such as those for notes) and duplicate include stacks when
    198 /// repeated warnings occur within the same file. It also handles the logic
    199 /// of customizing the formatting and display of the include stack.
    200 ///
    201 /// \param Loc   The diagnostic location.
    202 /// \param PLoc  The presumed location of the diagnostic location.
    203 /// \param Level The diagnostic level of the message this stack pertains to.
    204 void DiagnosticRenderer::emitIncludeStack(SourceLocation Loc,
    205                                           PresumedLoc PLoc,
    206                                           DiagnosticsEngine::Level Level,
    207                                           const SourceManager &SM) {
    208   SourceLocation IncludeLoc = PLoc.getIncludeLoc();
    209 
    210   // Skip redundant include stacks altogether.
    211   if (LastIncludeLoc == IncludeLoc)
    212     return;
    213 
    214   LastIncludeLoc = IncludeLoc;
    215 
    216   if (!DiagOpts->ShowNoteIncludeStack && Level == DiagnosticsEngine::Note)
    217     return;
    218 
    219   if (IncludeLoc.isValid())
    220     emitIncludeStackRecursively(IncludeLoc, SM);
    221   else {
    222     emitModuleBuildStack(SM);
    223     emitImportStack(Loc, SM);
    224   }
    225 }
    226 
    227 /// \brief Helper to recursivly walk up the include stack and print each layer
    228 /// on the way back down.
    229 void DiagnosticRenderer::emitIncludeStackRecursively(SourceLocation Loc,
    230                                                      const SourceManager &SM) {
    231   if (Loc.isInvalid()) {
    232     emitModuleBuildStack(SM);
    233     return;
    234   }
    235 
    236   PresumedLoc PLoc = SM.getPresumedLoc(Loc, DiagOpts->ShowPresumedLoc);
    237   if (PLoc.isInvalid())
    238     return;
    239 
    240   // If this source location was imported from a module, print the module
    241   // import stack rather than the
    242   // FIXME: We want submodule granularity here.
    243   std::pair<SourceLocation, StringRef> Imported = SM.getModuleImportLoc(Loc);
    244   if (Imported.first.isValid()) {
    245     // This location was imported by a module. Emit the module import stack.
    246     emitImportStackRecursively(Imported.first, Imported.second, SM);
    247     return;
    248   }
    249 
    250   // Emit the other include frames first.
    251   emitIncludeStackRecursively(PLoc.getIncludeLoc(), SM);
    252 
    253   // Emit the inclusion text/note.
    254   emitIncludeLocation(Loc, PLoc, SM);
    255 }
    256 
    257 /// \brief Emit the module import stack associated with the current location.
    258 void DiagnosticRenderer::emitImportStack(SourceLocation Loc,
    259                                          const SourceManager &SM) {
    260   if (Loc.isInvalid()) {
    261     emitModuleBuildStack(SM);
    262     return;
    263   }
    264 
    265   std::pair<SourceLocation, StringRef> NextImportLoc
    266     = SM.getModuleImportLoc(Loc);
    267   emitImportStackRecursively(NextImportLoc.first, NextImportLoc.second, SM);
    268 }
    269 
    270 /// \brief Helper to recursivly walk up the import stack and print each layer
    271 /// on the way back down.
    272 void DiagnosticRenderer::emitImportStackRecursively(SourceLocation Loc,
    273                                                     StringRef ModuleName,
    274                                                     const SourceManager &SM) {
    275   if (Loc.isInvalid()) {
    276     return;
    277   }
    278 
    279   PresumedLoc PLoc = SM.getPresumedLoc(Loc, DiagOpts->ShowPresumedLoc);
    280   if (PLoc.isInvalid())
    281     return;
    282 
    283   // Emit the other import frames first.
    284   std::pair<SourceLocation, StringRef> NextImportLoc
    285     = SM.getModuleImportLoc(Loc);
    286   emitImportStackRecursively(NextImportLoc.first, NextImportLoc.second, SM);
    287 
    288   // Emit the inclusion text/note.
    289   emitImportLocation(Loc, PLoc, ModuleName, SM);
    290 }
    291 
    292 /// \brief Emit the module build stack, for cases where a module is (re-)built
    293 /// on demand.
    294 void DiagnosticRenderer::emitModuleBuildStack(const SourceManager &SM) {
    295   ModuleBuildStack Stack = SM.getModuleBuildStack();
    296   for (unsigned I = 0, N = Stack.size(); I != N; ++I) {
    297     const SourceManager &CurSM = Stack[I].second.getManager();
    298     SourceLocation CurLoc = Stack[I].second;
    299     emitBuildingModuleLocation(CurLoc,
    300                                CurSM.getPresumedLoc(CurLoc,
    301                                                     DiagOpts->ShowPresumedLoc),
    302                                Stack[I].first,
    303                                CurSM);
    304   }
    305 }
    306 
    307 // Helper function to fix up source ranges.  It takes in an array of ranges,
    308 // and outputs an array of ranges where we want to draw the range highlighting
    309 // around the location specified by CaretLoc.
    310 //
    311 // To find locations which correspond to the caret, we crawl the macro caller
    312 // chain for the beginning and end of each range.  If the caret location
    313 // is in a macro expansion, we search each chain for a location
    314 // in the same expansion as the caret; otherwise, we crawl to the top of
    315 // each chain. Two locations are part of the same macro expansion
    316 // iff the FileID is the same.
    317 static void mapDiagnosticRanges(
    318     SourceLocation CaretLoc,
    319     ArrayRef<CharSourceRange> Ranges,
    320     SmallVectorImpl<CharSourceRange> &SpellingRanges,
    321     const SourceManager *SM) {
    322   FileID CaretLocFileID = SM->getFileID(CaretLoc);
    323 
    324   for (ArrayRef<CharSourceRange>::const_iterator I = Ranges.begin(),
    325        E = Ranges.end();
    326        I != E; ++I) {
    327     SourceLocation Begin = I->getBegin(), End = I->getEnd();
    328     bool IsTokenRange = I->isTokenRange();
    329 
    330     FileID BeginFileID = SM->getFileID(Begin);
    331     FileID EndFileID = SM->getFileID(End);
    332 
    333     // Find the common parent for the beginning and end of the range.
    334 
    335     // First, crawl the expansion chain for the beginning of the range.
    336     llvm::SmallDenseMap<FileID, SourceLocation> BeginLocsMap;
    337     while (Begin.isMacroID() && BeginFileID != EndFileID) {
    338       BeginLocsMap[BeginFileID] = Begin;
    339       Begin = SM->getImmediateExpansionRange(Begin).first;
    340       BeginFileID = SM->getFileID(Begin);
    341     }
    342 
    343     // Then, crawl the expansion chain for the end of the range.
    344     if (BeginFileID != EndFileID) {
    345       while (End.isMacroID() && !BeginLocsMap.count(EndFileID)) {
    346         End = SM->getImmediateExpansionRange(End).second;
    347         EndFileID = SM->getFileID(End);
    348       }
    349       if (End.isMacroID()) {
    350         Begin = BeginLocsMap[EndFileID];
    351         BeginFileID = EndFileID;
    352       }
    353     }
    354 
    355     while (Begin.isMacroID() && BeginFileID != CaretLocFileID) {
    356       if (SM->isMacroArgExpansion(Begin)) {
    357         Begin = SM->getImmediateSpellingLoc(Begin);
    358         End = SM->getImmediateSpellingLoc(End);
    359       } else {
    360         Begin = SM->getImmediateExpansionRange(Begin).first;
    361         End = SM->getImmediateExpansionRange(End).second;
    362       }
    363       BeginFileID = SM->getFileID(Begin);
    364       if (BeginFileID != SM->getFileID(End)) {
    365         // FIXME: Ugly hack to stop a crash; this code is making bad
    366         // assumptions and it's too complicated for me to reason
    367         // about.
    368         Begin = End = SourceLocation();
    369         break;
    370       }
    371     }
    372 
    373     // Return the spelling location of the beginning and end of the range.
    374     Begin = SM->getSpellingLoc(Begin);
    375     End = SM->getSpellingLoc(End);
    376     SpellingRanges.push_back(CharSourceRange(SourceRange(Begin, End),
    377                                              IsTokenRange));
    378   }
    379 }
    380 
    381 void DiagnosticRenderer::emitCaret(SourceLocation Loc,
    382                                    DiagnosticsEngine::Level Level,
    383                                    ArrayRef<CharSourceRange> Ranges,
    384                                    ArrayRef<FixItHint> Hints,
    385                                    const SourceManager &SM) {
    386   SmallVector<CharSourceRange, 4> SpellingRanges;
    387   mapDiagnosticRanges(Loc, Ranges, SpellingRanges, &SM);
    388   emitCodeContext(Loc, Level, SpellingRanges, Hints, SM);
    389 }
    390 
    391 /// \brief Recursively emit notes for each macro expansion and caret
    392 /// diagnostics where appropriate.
    393 ///
    394 /// Walks up the macro expansion stack printing expansion notes, the code
    395 /// snippet, caret, underlines and FixItHint display as appropriate at each
    396 /// level.
    397 ///
    398 /// \param Loc The location for this caret.
    399 /// \param Level The diagnostic level currently being emitted.
    400 /// \param Ranges The underlined ranges for this code snippet.
    401 /// \param Hints The FixIt hints active for this diagnostic.
    402 /// \param OnMacroInst The current depth of the macro expansion stack.
    403 void DiagnosticRenderer::emitMacroExpansions(SourceLocation Loc,
    404                                              DiagnosticsEngine::Level Level,
    405                                              ArrayRef<CharSourceRange> Ranges,
    406                                              ArrayRef<FixItHint> Hints,
    407                                              const SourceManager &SM,
    408                                              unsigned &MacroDepth,
    409                                              unsigned OnMacroInst) {
    410   assert(!Loc.isInvalid() && "must have a valid source location here");
    411 
    412   // Walk up to the caller of this macro, and produce a backtrace down to there.
    413   SourceLocation OneLevelUp = SM.getImmediateMacroCallerLoc(Loc);
    414   if (OneLevelUp.isMacroID())
    415     emitMacroExpansions(OneLevelUp, Level, Ranges, Hints, SM,
    416                         MacroDepth, OnMacroInst + 1);
    417   else
    418     MacroDepth = OnMacroInst + 1;
    419 
    420   unsigned MacroSkipStart = 0, MacroSkipEnd = 0;
    421   if (MacroDepth > DiagOpts->MacroBacktraceLimit &&
    422       DiagOpts->MacroBacktraceLimit != 0) {
    423     MacroSkipStart = DiagOpts->MacroBacktraceLimit / 2 +
    424     DiagOpts->MacroBacktraceLimit % 2;
    425     MacroSkipEnd = MacroDepth - DiagOpts->MacroBacktraceLimit / 2;
    426   }
    427 
    428   // Whether to suppress printing this macro expansion.
    429   bool Suppressed = (OnMacroInst >= MacroSkipStart &&
    430                      OnMacroInst < MacroSkipEnd);
    431 
    432   if (Suppressed) {
    433     // Tell the user that we've skipped contexts.
    434     if (OnMacroInst == MacroSkipStart) {
    435       SmallString<200> MessageStorage;
    436       llvm::raw_svector_ostream Message(MessageStorage);
    437       Message << "(skipping " << (MacroSkipEnd - MacroSkipStart)
    438               << " expansions in backtrace; use -fmacro-backtrace-limit=0 to "
    439                  "see all)";
    440       emitBasicNote(Message.str());
    441     }
    442     return;
    443   }
    444 
    445   // Find the spelling location for the macro definition. We must use the
    446   // spelling location here to avoid emitting a macro bactrace for the note.
    447   SourceLocation SpellingLoc = Loc;
    448   // If this is the expansion of a macro argument, point the caret at the
    449   // use of the argument in the definition of the macro, not the expansion.
    450   if (SM.isMacroArgExpansion(Loc))
    451     SpellingLoc = SM.getImmediateExpansionRange(Loc).first;
    452   SpellingLoc = SM.getSpellingLoc(SpellingLoc);
    453 
    454   // Map the ranges into the FileID of the diagnostic location.
    455   SmallVector<CharSourceRange, 4> SpellingRanges;
    456   mapDiagnosticRanges(Loc, Ranges, SpellingRanges, &SM);
    457 
    458   SmallString<100> MessageStorage;
    459   llvm::raw_svector_ostream Message(MessageStorage);
    460   StringRef MacroName = getImmediateMacroName(Loc, SM, LangOpts);
    461   if (MacroName.empty())
    462     Message << "expanded from here";
    463   else
    464     Message << "expanded from macro '" << MacroName << "'";
    465   emitDiagnostic(SpellingLoc, DiagnosticsEngine::Note,
    466                  Message.str(),
    467                  SpellingRanges, ArrayRef<FixItHint>(), &SM);
    468 }
    469 
    470 DiagnosticNoteRenderer::~DiagnosticNoteRenderer() {}
    471 
    472 void DiagnosticNoteRenderer::emitIncludeLocation(SourceLocation Loc,
    473                                                  PresumedLoc PLoc,
    474                                                  const SourceManager &SM) {
    475   // Generate a note indicating the include location.
    476   SmallString<200> MessageStorage;
    477   llvm::raw_svector_ostream Message(MessageStorage);
    478   Message << "in file included from " << PLoc.getFilename() << ':'
    479           << PLoc.getLine() << ":";
    480   emitNote(Loc, Message.str(), &SM);
    481 }
    482 
    483 void DiagnosticNoteRenderer::emitImportLocation(SourceLocation Loc,
    484                                                 PresumedLoc PLoc,
    485                                                 StringRef ModuleName,
    486                                                 const SourceManager &SM) {
    487   // Generate a note indicating the include location.
    488   SmallString<200> MessageStorage;
    489   llvm::raw_svector_ostream Message(MessageStorage);
    490   Message << "in module '" << ModuleName << "' imported from "
    491           << PLoc.getFilename() << ':' << PLoc.getLine() << ":";
    492   emitNote(Loc, Message.str(), &SM);
    493 }
    494 
    495 void
    496 DiagnosticNoteRenderer::emitBuildingModuleLocation(SourceLocation Loc,
    497                                                    PresumedLoc PLoc,
    498                                                    StringRef ModuleName,
    499                                                    const SourceManager &SM) {
    500   // Generate a note indicating the include location.
    501   SmallString<200> MessageStorage;
    502   llvm::raw_svector_ostream Message(MessageStorage);
    503   Message << "while building module '" << ModuleName << "' imported from "
    504           << PLoc.getFilename() << ':' << PLoc.getLine() << ":";
    505   emitNote(Loc, Message.str(), &SM);
    506 }
    507 
    508 
    509 void DiagnosticNoteRenderer::emitBasicNote(StringRef Message) {
    510   emitNote(SourceLocation(), Message, 0);
    511 }
    512