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