Index: include/clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h =================================================================== --- include/clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h +++ include/clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h @@ -365,6 +365,9 @@ bool IsArg = false, bool EnableNullFPSuppression = true); +/// Print the counterexample as a C file. +void printCounterexample(BugReport &report); + const Expr *getDerefExpr(const Stmt *S); const Stmt *GetDenomExpr(const ExplodedNode *N); const Stmt *GetRetValExpr(const ExplodedNode *N); Index: lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp =================================================================== --- lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp +++ lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp @@ -95,6 +95,7 @@ if (ex) { R->addRange(ex->getSourceRange()); bugreporter::trackNullOrUndefValue(N, ex, *R); + bugreporter::printCounterexample(*R); } C.emitReport(std::move(R)); } Index: lib/StaticAnalyzer/Core/BugReporterVisitors.cpp =================================================================== --- lib/StaticAnalyzer/Core/BugReporterVisitors.cpp +++ lib/StaticAnalyzer/Core/BugReporterVisitors.cpp @@ -11,6 +11,8 @@ // enhance the diagnostics reported for a bug. // //===----------------------------------------------------------------------===// +#include +#include #include "clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h" #include "clang/AST/Expr.h" #include "clang/AST/ExprObjC.h" @@ -24,6 +26,7 @@ #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h" #include "llvm/ADT/SmallString.h" #include "llvm/ADT/StringExtras.h" +#include "llvm/ADT/SetVector.h" #include "llvm/Support/raw_ostream.h" using namespace clang; @@ -1878,3 +1881,150 @@ return std::move(Piece); } + +/// Export the counterexample to C. +class PrinterVisitor final : public BugReporterVisitorImpl { + + /// File ID followed by a line number. + llvm::SetVector> VisitedLines; + mutable bool DonePrinting = false; + + /// Output stream to write into. + raw_ostream &Ostream; + + /// Max number of chars used to display the filename. + static const unsigned MAX_FILENAME_MARGIN = 80; + static const unsigned MARGIN_SEP_LEN = 1; + +public: + PrinterVisitor(raw_ostream &Ostream) : Ostream(Ostream) {} + + void Profile(llvm::FoldingSetNodeID &ID) const override { + static int Tag = 0; + ID.AddPointer(&Tag); + } + + std::shared_ptr VisitNode(const ExplodedNode *N, + const ExplodedNode *PrevN, + BugReporterContext &BRC, + BugReport &BR) override { + SourceManager &SM = BRC.getSourceManager(); + + if (DonePrinting) { // Printing was done, do nothing. + return nullptr; + } else if (!PrevN->getFirstPred()) { // Finished report, do printing. + + // Went through the entire bug report, now print the lines in reverse + // order. + bool Status = doPrinting(SM); + if (!Status) + Ostream << "Error while printing\n"; + Ostream << "/* ============================================== */\n"; + DonePrinting = true; + return nullptr; + } else if (Optional PS = N->getLocation().getAs()) { + + // Statement location with an associated SourceLocation object. + SourceLocation Loc = PS->getStmt()->getSourceRange().getBegin(); + + // FIXME: might be necessary to insert the spelling location as well. + insertLoc(SM, SM.getExpansionLoc(Loc)); + } + return nullptr; + } + +private: + /// Print locations serialized to \c VisitedLines. + bool doPrinting(SourceManager &SM) { + unsigned Margin = calculateMargin(SM); + for (auto It = VisitedLines.rbegin(), + ItEnd = VisitedLines.rend(); + It != ItEnd; ++It) { + FileID FID = It->first; + unsigned LineNo = It->second; + bool Status = printLine(SM, FID, LineNo, Margin); + if (!Status) + return false; + } + return true; + } + + /// Print line \p LineNo from file \p FID, with left margin \p Margin. + /// \return \c true on success, \c false on failure. + bool printLine(SourceManager &SM, FileID FID, + unsigned LineNo, unsigned Margin) { + SourceLocation Location = SM.translateLineCol(FID, LineNo, 1); + unsigned Offset = SM.getFileOffset(Location); + + // Print location first. + int Status = printLocation(SM, Location, Margin); + if (!Status) + return false; + + bool Invalid = false; + const char *BufferStart = SM.getBufferData(FID, &Invalid).data(); + if (Invalid) + return false; + + unsigned FileEndOffset = SM.getFileOffset(SM.getLocForEndOfFile(FID)); + for (unsigned i=Offset; BufferStart[i] != '\n' && i < FileEndOffset; ++i) + Ostream << BufferStart[i]; + + Ostream << "\n"; + return true; + } + + /// Print location in left margin. + bool printLocation(SourceManager &SM, SourceLocation Loc, unsigned Margin) { + Loc = SM.getExpansionLoc(Loc); + PresumedLoc PLoc = SM.getPresumedLoc(Loc); + if (PLoc.isInvalid()) + return false; + + uint64_t SavedPos = Ostream.tell(); + Ostream << PLoc.getFilename() << ":" << PLoc.getLine(); + uint64_t Delta = Ostream.tell() - SavedPos; + assert(Margin >= Delta); + for (unsigned i=Delta; i 0); + unsigned RequiredMargin = strnlen(Filename, MAX_FILENAME_MARGIN) + + LineMargin + MARGIN_SEP_LEN; + if (RequiredMargin > Out) + Out = RequiredMargin; + } + return Out; + } +}; + +void bugreporter::printCounterexample(BugReport &report) { + report.addVisitor(llvm::make_unique(llvm::errs())); +}