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Diffstat (limited to 'lib/ProfileData/CoverageMappingWriter.cpp')
| -rw-r--r-- | lib/ProfileData/CoverageMappingWriter.cpp | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/lib/ProfileData/CoverageMappingWriter.cpp b/lib/ProfileData/CoverageMappingWriter.cpp new file mode 100644 index 0000000..6969c2a --- /dev/null +++ b/lib/ProfileData/CoverageMappingWriter.cpp @@ -0,0 +1,187 @@ +//=-- CoverageMappingWriter.cpp - Code coverage mapping writer -------------=// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file contains support for writing coverage mapping data for +// instrumentation based coverage. +// +//===----------------------------------------------------------------------===// + +#include "llvm/ProfileData/CoverageMappingWriter.h" +#include "llvm/Support/LEB128.h" + +using namespace llvm; +using namespace coverage; + +void CoverageFilenamesSectionWriter::write(raw_ostream &OS) { + encodeULEB128(Filenames.size(), OS); + for (const auto &Filename : Filenames) { + encodeULEB128(Filename.size(), OS); + OS << Filename; + } +} + +namespace { +/// \brief Gather only the expressions that are used by the mapping +/// regions in this function. +class CounterExpressionsMinimizer { + ArrayRef<CounterExpression> Expressions; + llvm::SmallVector<CounterExpression, 16> UsedExpressions; + std::vector<unsigned> AdjustedExpressionIDs; + +public: + void mark(Counter C) { + if (!C.isExpression()) + return; + unsigned ID = C.getExpressionID(); + AdjustedExpressionIDs[ID] = 1; + mark(Expressions[ID].LHS); + mark(Expressions[ID].RHS); + } + + void gatherUsed(Counter C) { + if (!C.isExpression() || !AdjustedExpressionIDs[C.getExpressionID()]) + return; + AdjustedExpressionIDs[C.getExpressionID()] = UsedExpressions.size(); + const auto &E = Expressions[C.getExpressionID()]; + UsedExpressions.push_back(E); + gatherUsed(E.LHS); + gatherUsed(E.RHS); + } + + CounterExpressionsMinimizer(ArrayRef<CounterExpression> Expressions, + ArrayRef<CounterMappingRegion> MappingRegions) + : Expressions(Expressions) { + AdjustedExpressionIDs.resize(Expressions.size(), 0); + for (const auto &I : MappingRegions) + mark(I.Count); + for (const auto &I : MappingRegions) + gatherUsed(I.Count); + } + + ArrayRef<CounterExpression> getExpressions() const { return UsedExpressions; } + + /// \brief Adjust the given counter to correctly transition from the old + /// expression ids to the new expression ids. + Counter adjust(Counter C) const { + if (C.isExpression()) + C = Counter::getExpression(AdjustedExpressionIDs[C.getExpressionID()]); + return C; + } +}; +} + +/// \brief Encode the counter. +/// +/// The encoding uses the following format: +/// Low 2 bits - Tag: +/// Counter::Zero(0) - A Counter with kind Counter::Zero +/// Counter::CounterValueReference(1) - A counter with kind +/// Counter::CounterValueReference +/// Counter::Expression(2) + CounterExpression::Subtract(0) - +/// A counter with kind Counter::Expression and an expression +/// with kind CounterExpression::Subtract +/// Counter::Expression(2) + CounterExpression::Add(1) - +/// A counter with kind Counter::Expression and an expression +/// with kind CounterExpression::Add +/// Remaining bits - Counter/Expression ID. +static unsigned encodeCounter(ArrayRef<CounterExpression> Expressions, + Counter C) { + unsigned Tag = unsigned(C.getKind()); + if (C.isExpression()) + Tag += Expressions[C.getExpressionID()].Kind; + unsigned ID = C.getCounterID(); + assert(ID <= + (std::numeric_limits<unsigned>::max() >> Counter::EncodingTagBits)); + return Tag | (ID << Counter::EncodingTagBits); +} + +static void writeCounter(ArrayRef<CounterExpression> Expressions, Counter C, + raw_ostream &OS) { + encodeULEB128(encodeCounter(Expressions, C), OS); +} + +void CoverageMappingWriter::write(raw_ostream &OS) { + // Sort the regions in an ascending order by the file id and the starting + // location. + std::sort(MappingRegions.begin(), MappingRegions.end()); + + // Write out the fileid -> filename mapping. + encodeULEB128(VirtualFileMapping.size(), OS); + for (const auto &FileID : VirtualFileMapping) + encodeULEB128(FileID, OS); + + // Write out the expressions. + CounterExpressionsMinimizer Minimizer(Expressions, MappingRegions); + auto MinExpressions = Minimizer.getExpressions(); + encodeULEB128(MinExpressions.size(), OS); + for (const auto &E : MinExpressions) { + writeCounter(MinExpressions, Minimizer.adjust(E.LHS), OS); + writeCounter(MinExpressions, Minimizer.adjust(E.RHS), OS); + } + + // Write out the mapping regions. + // Split the regions into subarrays where each region in a + // subarray has a fileID which is the index of that subarray. + unsigned PrevLineStart = 0; + unsigned CurrentFileID = ~0U; + for (auto I = MappingRegions.begin(), E = MappingRegions.end(); I != E; ++I) { + if (I->FileID != CurrentFileID) { + // Ensure that all file ids have at least one mapping region. + assert(I->FileID == (CurrentFileID + 1)); + // Find the number of regions with this file id. + unsigned RegionCount = 1; + for (auto J = I + 1; J != E && I->FileID == J->FileID; ++J) + ++RegionCount; + // Start a new region sub-array. + encodeULEB128(RegionCount, OS); + + CurrentFileID = I->FileID; + PrevLineStart = 0; + } + Counter Count = Minimizer.adjust(I->Count); + switch (I->Kind) { + case CounterMappingRegion::CodeRegion: + writeCounter(MinExpressions, Count, OS); + break; + case CounterMappingRegion::ExpansionRegion: { + assert(Count.isZero()); + assert(I->ExpandedFileID <= + (std::numeric_limits<unsigned>::max() >> + Counter::EncodingCounterTagAndExpansionRegionTagBits)); + // Mark an expansion region with a set bit that follows the counter tag, + // and pack the expanded file id into the remaining bits. + unsigned EncodedTagExpandedFileID = + (1 << Counter::EncodingTagBits) | + (I->ExpandedFileID + << Counter::EncodingCounterTagAndExpansionRegionTagBits); + encodeULEB128(EncodedTagExpandedFileID, OS); + break; + } + case CounterMappingRegion::SkippedRegion: + assert(Count.isZero()); + encodeULEB128(unsigned(I->Kind) + << Counter::EncodingCounterTagAndExpansionRegionTagBits, + OS); + break; + } + assert(I->LineStart >= PrevLineStart); + encodeULEB128(I->LineStart - PrevLineStart, OS); + uint64_t CodeBeforeColumnStart = + uint64_t(I->HasCodeBefore) | + (uint64_t(I->ColumnStart) + << CounterMappingRegion::EncodingHasCodeBeforeBits); + encodeULEB128(CodeBeforeColumnStart, OS); + assert(I->LineEnd >= I->LineStart); + encodeULEB128(I->LineEnd - I->LineStart, OS); + encodeULEB128(I->ColumnEnd, OS); + PrevLineStart = I->LineStart; + } + // Ensure that all file ids have at least one mapping region. + assert(CurrentFileID == (VirtualFileMapping.size() - 1)); +} |