Add option to include multiple lines in snippets.
When a diagnostic includes a highlighted range spanning multiple lines, clang
now supports printing out multiple lines of context if necessary to show the
highlighted ranges. This is not yet exposed in the driver, but can be enabled
by "-Xclang -fcaret-diagnostics-max-lines -Xclang N".
This is experimental until we can find out whether it works well in practice,
and if so, what a good default for the maximum number of lines is.
llvm-svn: 303589
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 51147b6..29cdcd7 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -1087,6 +1087,9 @@
Opts.SpellCheckingLimit = getLastArgIntValue(
Args, OPT_fspell_checking_limit,
DiagnosticOptions::DefaultSpellCheckingLimit, Diags);
+ Opts.SnippetLineLimit = getLastArgIntValue(
+ Args, OPT_fcaret_diagnostics_max_lines,
+ DiagnosticOptions::DefaultSnippetLineLimit, Diags);
Opts.TabStop = getLastArgIntValue(Args, OPT_ftabstop,
DiagnosticOptions::DefaultTabStop, Diags);
if (Opts.TabStop == 0 || Opts.TabStop > DiagnosticOptions::MaxTabStop) {
diff --git a/clang/lib/Frontend/TextDiagnostic.cpp b/clang/lib/Frontend/TextDiagnostic.cpp
index a493738..a18b8c8 100644
--- a/clang/lib/Frontend/TextDiagnostic.cpp
+++ b/clang/lib/Frontend/TextDiagnostic.cpp
@@ -928,6 +928,56 @@
OS << "While building module '" << ModuleName << "':\n";
}
+/// \brief Find the suitable set of lines to show to include a set of ranges.
+static llvm::Optional<std::pair<unsigned, unsigned>>
+findLinesForRange(const CharSourceRange &R, FileID FID,
+ const SourceManager &SM) {
+ if (!R.isValid()) return None;
+
+ SourceLocation Begin = R.getBegin();
+ SourceLocation End = R.getEnd();
+ if (SM.getFileID(Begin) != FID || SM.getFileID(End) != FID)
+ return None;
+
+ return std::make_pair(SM.getExpansionLineNumber(Begin),
+ SM.getExpansionLineNumber(End));
+}
+
+/// Add as much of range B into range A as possible without exceeding a maximum
+/// size of MaxRange. Ranges are inclusive.
+std::pair<unsigned, unsigned> maybeAddRange(std::pair<unsigned, unsigned> A,
+ std::pair<unsigned, unsigned> B,
+ unsigned MaxRange) {
+ // If A is already the maximum size, we're done.
+ unsigned Slack = MaxRange - (A.second - A.first + 1);
+ if (Slack == 0)
+ return A;
+
+ // Easy case: merge succeeds within MaxRange.
+ unsigned Min = std::min(A.first, B.first);
+ unsigned Max = std::max(A.second, B.second);
+ if (Max - Min + 1 <= MaxRange)
+ return {Min, Max};
+
+ // If we can't reach B from A within MaxRange, there's nothing to do.
+ // Don't add lines to the range that contain nothing interesting.
+ if ((B.first > A.first && B.first - A.first + 1 > MaxRange) ||
+ (B.second < A.second && A.second - B.second + 1 > MaxRange))
+ return A;
+
+ // Otherwise, expand A towards B to produce a range of size MaxRange. We
+ // attempt to expand by the same amount in both directions if B strictly
+ // contains A.
+
+ // Expand downwards by up to half the available amount, then upwards as
+ // much as possible, then downwards as much as possible.
+ A.second = std::min(A.second + (Slack + 1) / 2, Max);
+ Slack = MaxRange - (A.second - A.first + 1);
+ A.first = std::max(Min + Slack, A.first) - Slack;
+ A.second = std::min(A.first + MaxRange - 1, Max);
+ return A;
+}
+
/// \brief Highlight a SourceRange (with ~'s) for any characters on LineNo.
static void highlightRange(const CharSourceRange &R,
unsigned LineNo, FileID FID,
@@ -990,9 +1040,12 @@
EndColNo = map.startOfPreviousColumn(EndColNo);
// If the start/end passed each other, then we are trying to highlight a
- // range that just exists in whitespace, which must be some sort of other
- // bug.
- assert(StartColNo <= EndColNo && "Trying to highlight whitespace??");
+ // range that just exists in whitespace. That most likely means we have
+ // a multi-line highlighting range that covers a blank line.
+ if (StartColNo > EndColNo) {
+ assert(StartLineNo != EndLineNo && "trying to highlight whitespace");
+ StartColNo = EndColNo;
+ }
}
assert(StartColNo <= map.getSourceLine().size() && "Invalid range!");
@@ -1103,7 +1156,7 @@
// Decompose the location into a FID/Offset pair.
std::pair<FileID, unsigned> LocInfo = SM.getDecomposedLoc(Loc);
FileID FID = LocInfo.first;
- unsigned FileOffset = LocInfo.second;
+ unsigned CaretFileOffset = LocInfo.second;
// Get information about the buffer it points into.
bool Invalid = false;
@@ -1111,101 +1164,118 @@
if (Invalid)
return;
- const char *BufStart = BufData.data();
- const char *BufEnd = BufStart + BufData.size();
+ unsigned CaretLineNo = SM.getLineNumber(FID, CaretFileOffset);
+ unsigned CaretColNo = SM.getColumnNumber(FID, CaretFileOffset);
- unsigned LineNo = SM.getLineNumber(FID, FileOffset);
- unsigned ColNo = SM.getColumnNumber(FID, FileOffset);
-
// Arbitrarily stop showing snippets when the line is too long.
static const size_t MaxLineLengthToPrint = 4096;
- if (ColNo > MaxLineLengthToPrint)
+ if (CaretColNo > MaxLineLengthToPrint)
return;
- // Rewind from the current position to the start of the line.
- const char *TokPtr = BufStart+FileOffset;
- const char *LineStart = TokPtr-ColNo+1; // Column # is 1-based.
-
- // Compute the line end. Scan forward from the error position to the end of
- // the line.
- const char *LineEnd = TokPtr;
- while (*LineEnd != '\n' && *LineEnd != '\r' && LineEnd != BufEnd)
- ++LineEnd;
-
- // Arbitrarily stop showing snippets when the line is too long.
- if (size_t(LineEnd - LineStart) > MaxLineLengthToPrint)
- return;
-
- // Trim trailing null-bytes.
- StringRef Line(LineStart, LineEnd - LineStart);
- while (Line.size() > ColNo && Line.back() == '\0')
- Line = Line.drop_back();
-
- // Copy the line of code into an std::string for ease of manipulation.
- std::string SourceLine(Line.begin(), Line.end());
-
- // Build the byte to column map.
- const SourceColumnMap sourceColMap(SourceLine, DiagOpts->TabStop);
-
- // Create a line for the caret that is filled with spaces that is the same
- // number of columns as the line of source code.
- std::string CaretLine(sourceColMap.columns(), ' ');
-
- // Highlight all of the characters covered by Ranges with ~ characters.
+ // Find the set of lines to include.
+ const unsigned MaxLines = DiagOpts->SnippetLineLimit;
+ std::pair<unsigned, unsigned> Lines = {CaretLineNo, CaretLineNo};
for (SmallVectorImpl<CharSourceRange>::iterator I = Ranges.begin(),
E = Ranges.end();
I != E; ++I)
- highlightRange(*I, LineNo, FID, sourceColMap, CaretLine, SM, LangOpts);
+ if (auto OptionalRange = findLinesForRange(*I, FID, SM))
+ Lines = maybeAddRange(Lines, *OptionalRange, MaxLines);
- // Next, insert the caret itself.
- ColNo = sourceColMap.byteToContainingColumn(ColNo-1);
- if (CaretLine.size()<ColNo+1)
- CaretLine.resize(ColNo+1, ' ');
- CaretLine[ColNo] = '^';
+ for (unsigned LineNo = Lines.first; LineNo != Lines.second + 1; ++LineNo) {
+ const char *BufStart = BufData.data();
+ const char *BufEnd = BufStart + BufData.size();
- std::string FixItInsertionLine = buildFixItInsertionLine(LineNo,
- sourceColMap,
- Hints, SM,
- DiagOpts.get());
+ // Rewind from the current position to the start of the line.
+ const char *LineStart =
+ BufStart +
+ SM.getDecomposedLoc(SM.translateLineCol(FID, LineNo, 1)).second;
+ if (LineStart == BufEnd)
+ break;
- // If the source line is too long for our terminal, select only the
- // "interesting" source region within that line.
- unsigned Columns = DiagOpts->MessageLength;
- if (Columns)
- selectInterestingSourceRegion(SourceLine, CaretLine, FixItInsertionLine,
- Columns, sourceColMap);
+ // Compute the line end.
+ const char *LineEnd = LineStart;
+ while (*LineEnd != '\n' && *LineEnd != '\r' && LineEnd != BufEnd)
+ ++LineEnd;
- // If we are in -fdiagnostics-print-source-range-info mode, we are trying
- // to produce easily machine parsable output. Add a space before the
- // source line and the caret to make it trivial to tell the main diagnostic
- // line from what the user is intended to see.
- if (DiagOpts->ShowSourceRanges) {
- SourceLine = ' ' + SourceLine;
- CaretLine = ' ' + CaretLine;
- }
+ // Arbitrarily stop showing snippets when the line is too long.
+ // FIXME: Don't print any lines in this case.
+ if (size_t(LineEnd - LineStart) > MaxLineLengthToPrint)
+ return;
- // Finally, remove any blank spaces from the end of CaretLine.
- while (CaretLine[CaretLine.size()-1] == ' ')
- CaretLine.erase(CaretLine.end()-1);
+ // Trim trailing null-bytes.
+ StringRef Line(LineStart, LineEnd - LineStart);
+ while (!Line.empty() && Line.back() == '\0' &&
+ (LineNo != CaretLineNo || Line.size() > CaretColNo))
+ Line = Line.drop_back();
- // Emit what we have computed.
- emitSnippet(SourceLine);
+ // Copy the line of code into an std::string for ease of manipulation.
+ std::string SourceLine(Line.begin(), Line.end());
- if (DiagOpts->ShowColors)
- OS.changeColor(caretColor, true);
- OS << CaretLine << '\n';
- if (DiagOpts->ShowColors)
- OS.resetColor();
+ // Build the byte to column map.
+ const SourceColumnMap sourceColMap(SourceLine, DiagOpts->TabStop);
- if (!FixItInsertionLine.empty()) {
- if (DiagOpts->ShowColors)
- // Print fixit line in color
- OS.changeColor(fixitColor, false);
- if (DiagOpts->ShowSourceRanges)
- OS << ' ';
- OS << FixItInsertionLine << '\n';
- if (DiagOpts->ShowColors)
- OS.resetColor();
+ // Create a line for the caret that is filled with spaces that is the same
+ // number of columns as the line of source code.
+ std::string CaretLine(sourceColMap.columns(), ' ');
+
+ // Highlight all of the characters covered by Ranges with ~ characters.
+ for (SmallVectorImpl<CharSourceRange>::iterator I = Ranges.begin(),
+ E = Ranges.end();
+ I != E; ++I)
+ highlightRange(*I, LineNo, FID, sourceColMap, CaretLine, SM, LangOpts);
+
+ // Next, insert the caret itself.
+ if (CaretLineNo == LineNo) {
+ CaretColNo = sourceColMap.byteToContainingColumn(CaretColNo - 1);
+ if (CaretLine.size() < CaretColNo + 1)
+ CaretLine.resize(CaretColNo + 1, ' ');
+ CaretLine[CaretColNo] = '^';
+ }
+
+ std::string FixItInsertionLine = buildFixItInsertionLine(
+ LineNo, sourceColMap, Hints, SM, DiagOpts.get());
+
+ // If the source line is too long for our terminal, select only the
+ // "interesting" source region within that line.
+ unsigned Columns = DiagOpts->MessageLength;
+ if (Columns)
+ selectInterestingSourceRegion(SourceLine, CaretLine, FixItInsertionLine,
+ Columns, sourceColMap);
+
+ // If we are in -fdiagnostics-print-source-range-info mode, we are trying
+ // to produce easily machine parsable output. Add a space before the
+ // source line and the caret to make it trivial to tell the main diagnostic
+ // line from what the user is intended to see.
+ if (DiagOpts->ShowSourceRanges) {
+ SourceLine = ' ' + SourceLine;
+ CaretLine = ' ' + CaretLine;
+ }
+
+ // Finally, remove any blank spaces from the end of CaretLine.
+ while (CaretLine[CaretLine.size() - 1] == ' ')
+ CaretLine.erase(CaretLine.end() - 1);
+
+ // Emit what we have computed.
+ emitSnippet(SourceLine);
+
+ if (!CaretLine.empty()) {
+ if (DiagOpts->ShowColors)
+ OS.changeColor(caretColor, true);
+ OS << CaretLine << '\n';
+ if (DiagOpts->ShowColors)
+ OS.resetColor();
+ }
+
+ if (!FixItInsertionLine.empty()) {
+ if (DiagOpts->ShowColors)
+ // Print fixit line in color
+ OS.changeColor(fixitColor, false);
+ if (DiagOpts->ShowSourceRanges)
+ OS << ' ';
+ OS << FixItInsertionLine << '\n';
+ if (DiagOpts->ShowColors)
+ OS.resetColor();
+ }
}
// Print out any parseable fixit information requested by the options.