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CoverageMappingGen.cpp
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//===--- CoverageMappingGen.cpp - Coverage mapping generation ---*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// Instrumentation-based code coverage mapping generator
//
//===----------------------------------------------------------------------===//
#include "CoverageMappingGen.h"
#include "CodeGenFunction.h"
#include "clang/AST/StmtVisitor.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Lex/Lexer.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ProfileData/Coverage/CoverageMapping.h"
#include "llvm/ProfileData/Coverage/CoverageMappingReader.h"
#include "llvm/ProfileData/Coverage/CoverageMappingWriter.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include <optional>
// This selects the coverage mapping format defined when `InstrProfData.inc`
// is textually included.
#define COVMAP_V3
namespace llvm {
cl::opt<bool>
EnableSingleByteCoverage("enable-single-byte-coverage",
llvm::cl::ZeroOrMore,
llvm::cl::desc("Enable single byte coverage"),
llvm::cl::Hidden, llvm::cl::init(false));
} // namespace llvm
static llvm::cl::opt<bool> EmptyLineCommentCoverage(
"emptyline-comment-coverage",
llvm::cl::desc("Emit emptylines and comment lines as skipped regions (only "
"disable it on test)"),
llvm::cl::init(true), llvm::cl::Hidden);
namespace llvm::coverage {
cl::opt<bool> SystemHeadersCoverage(
"system-headers-coverage",
cl::desc("Enable collecting coverage from system headers"), cl::init(false),
cl::Hidden);
}
using namespace clang;
using namespace CodeGen;
using namespace llvm::coverage;
CoverageSourceInfo *
CoverageMappingModuleGen::setUpCoverageCallbacks(Preprocessor &PP) {
CoverageSourceInfo *CoverageInfo =
new CoverageSourceInfo(PP.getSourceManager());
PP.addPPCallbacks(std::unique_ptr<PPCallbacks>(CoverageInfo));
if (EmptyLineCommentCoverage) {
PP.addCommentHandler(CoverageInfo);
PP.setEmptylineHandler(CoverageInfo);
PP.setPreprocessToken(true);
PP.setTokenWatcher([CoverageInfo](clang::Token Tok) {
// Update previous token location.
CoverageInfo->PrevTokLoc = Tok.getLocation();
if (Tok.getKind() != clang::tok::eod)
CoverageInfo->updateNextTokLoc(Tok.getLocation());
});
}
return CoverageInfo;
}
void CoverageSourceInfo::AddSkippedRange(SourceRange Range,
SkippedRange::Kind RangeKind) {
if (EmptyLineCommentCoverage && !SkippedRanges.empty() &&
PrevTokLoc == SkippedRanges.back().PrevTokLoc &&
SourceMgr.isWrittenInSameFile(SkippedRanges.back().Range.getEnd(),
Range.getBegin()))
SkippedRanges.back().Range.setEnd(Range.getEnd());
else
SkippedRanges.push_back({Range, RangeKind, PrevTokLoc});
}
void CoverageSourceInfo::SourceRangeSkipped(SourceRange Range, SourceLocation) {
AddSkippedRange(Range, SkippedRange::PPIfElse);
}
void CoverageSourceInfo::HandleEmptyline(SourceRange Range) {
AddSkippedRange(Range, SkippedRange::EmptyLine);
}
bool CoverageSourceInfo::HandleComment(Preprocessor &PP, SourceRange Range) {
AddSkippedRange(Range, SkippedRange::Comment);
return false;
}
void CoverageSourceInfo::updateNextTokLoc(SourceLocation Loc) {
if (!SkippedRanges.empty() && SkippedRanges.back().NextTokLoc.isInvalid())
SkippedRanges.back().NextTokLoc = Loc;
}
namespace {
/// A region of source code that can be mapped to a counter.
class SourceMappingRegion {
/// Primary Counter that is also used for Branch Regions for "True" branches.
Counter Count;
/// Secondary Counter used for Branch Regions for "False" branches.
std::optional<Counter> FalseCount;
/// Parameters used for Modified Condition/Decision Coverage
mcdc::Parameters MCDCParams;
/// The region's starting location.
std::optional<SourceLocation> LocStart;
/// The region's ending location.
std::optional<SourceLocation> LocEnd;
/// Whether this region is a gap region. The count from a gap region is set
/// as the line execution count if there are no other regions on the line.
bool GapRegion;
/// Whetever this region is skipped ('if constexpr' or 'if consteval' untaken
/// branch, or anything skipped but not empty line / comments)
bool SkippedRegion;
public:
SourceMappingRegion(Counter Count, std::optional<SourceLocation> LocStart,
std::optional<SourceLocation> LocEnd,
bool GapRegion = false)
: Count(Count), LocStart(LocStart), LocEnd(LocEnd), GapRegion(GapRegion),
SkippedRegion(false) {}
SourceMappingRegion(Counter Count, std::optional<Counter> FalseCount,
mcdc::Parameters MCDCParams,
std::optional<SourceLocation> LocStart,
std::optional<SourceLocation> LocEnd,
bool GapRegion = false)
: Count(Count), FalseCount(FalseCount), MCDCParams(MCDCParams),
LocStart(LocStart), LocEnd(LocEnd), GapRegion(GapRegion),
SkippedRegion(false) {}
SourceMappingRegion(mcdc::Parameters MCDCParams,
std::optional<SourceLocation> LocStart,
std::optional<SourceLocation> LocEnd)
: MCDCParams(MCDCParams), LocStart(LocStart), LocEnd(LocEnd),
GapRegion(false), SkippedRegion(false) {}
const Counter &getCounter() const { return Count; }
const Counter &getFalseCounter() const {
assert(FalseCount && "Region has no alternate counter");
return *FalseCount;
}
void setCounter(Counter C) { Count = C; }
bool hasStartLoc() const { return LocStart.has_value(); }
void setStartLoc(SourceLocation Loc) { LocStart = Loc; }
SourceLocation getBeginLoc() const {
assert(LocStart && "Region has no start location");
return *LocStart;
}
bool hasEndLoc() const { return LocEnd.has_value(); }
void setEndLoc(SourceLocation Loc) {
assert(Loc.isValid() && "Setting an invalid end location");
LocEnd = Loc;
}
SourceLocation getEndLoc() const {
assert(LocEnd && "Region has no end location");
return *LocEnd;
}
bool isGap() const { return GapRegion; }
void setGap(bool Gap) { GapRegion = Gap; }
bool isSkipped() const { return SkippedRegion; }
void setSkipped(bool Skipped) { SkippedRegion = Skipped; }
bool isBranch() const { return FalseCount.has_value(); }
bool isMCDCBranch() const {
return std::holds_alternative<mcdc::BranchParameters>(MCDCParams);
}
const auto &getMCDCBranchParams() const {
return mcdc::getParams<const mcdc::BranchParameters>(MCDCParams);
}
bool isMCDCDecision() const {
return std::holds_alternative<mcdc::DecisionParameters>(MCDCParams);
}
const auto &getMCDCDecisionParams() const {
return mcdc::getParams<const mcdc::DecisionParameters>(MCDCParams);
}
const mcdc::Parameters &getMCDCParams() const { return MCDCParams; }
void resetMCDCParams() { MCDCParams = mcdc::Parameters(); }
};
/// Spelling locations for the start and end of a source region.
struct SpellingRegion {
/// The line where the region starts.
unsigned LineStart;
/// The column where the region starts.
unsigned ColumnStart;
/// The line where the region ends.
unsigned LineEnd;
/// The column where the region ends.
unsigned ColumnEnd;
SpellingRegion(SourceManager &SM, SourceLocation LocStart,
SourceLocation LocEnd) {
LineStart = SM.getSpellingLineNumber(LocStart);
ColumnStart = SM.getSpellingColumnNumber(LocStart);
LineEnd = SM.getSpellingLineNumber(LocEnd);
ColumnEnd = SM.getSpellingColumnNumber(LocEnd);
}
SpellingRegion(SourceManager &SM, SourceMappingRegion &R)
: SpellingRegion(SM, R.getBeginLoc(), R.getEndLoc()) {}
/// Check if the start and end locations appear in source order, i.e
/// top->bottom, left->right.
bool isInSourceOrder() const {
return (LineStart < LineEnd) ||
(LineStart == LineEnd && ColumnStart <= ColumnEnd);
}
};
/// Provides the common functionality for the different
/// coverage mapping region builders.
class CoverageMappingBuilder {
public:
CoverageMappingModuleGen &CVM;
SourceManager &SM;
const LangOptions &LangOpts;
private:
/// Map of clang's FileIDs to IDs used for coverage mapping.
llvm::SmallDenseMap<FileID, std::pair<unsigned, SourceLocation>, 8>
FileIDMapping;
public:
/// The coverage mapping regions for this function
llvm::SmallVector<CounterMappingRegion, 32> MappingRegions;
/// The source mapping regions for this function.
std::vector<SourceMappingRegion> SourceRegions;
/// A set of regions which can be used as a filter.
///
/// It is produced by emitExpansionRegions() and is used in
/// emitSourceRegions() to suppress producing code regions if
/// the same area is covered by expansion regions.
typedef llvm::SmallSet<std::pair<SourceLocation, SourceLocation>, 8>
SourceRegionFilter;
CoverageMappingBuilder(CoverageMappingModuleGen &CVM, SourceManager &SM,
const LangOptions &LangOpts)
: CVM(CVM), SM(SM), LangOpts(LangOpts) {}
/// Return the precise end location for the given token.
SourceLocation getPreciseTokenLocEnd(SourceLocation Loc) {
// We avoid getLocForEndOfToken here, because it doesn't do what we want for
// macro locations, which we just treat as expanded files.
unsigned TokLen =
Lexer::MeasureTokenLength(SM.getSpellingLoc(Loc), SM, LangOpts);
return Loc.getLocWithOffset(TokLen);
}
/// Return the start location of an included file or expanded macro.
SourceLocation getStartOfFileOrMacro(SourceLocation Loc) {
if (Loc.isMacroID())
return Loc.getLocWithOffset(-SM.getFileOffset(Loc));
return SM.getLocForStartOfFile(SM.getFileID(Loc));
}
/// Return the end location of an included file or expanded macro.
SourceLocation getEndOfFileOrMacro(SourceLocation Loc) {
if (Loc.isMacroID())
return Loc.getLocWithOffset(SM.getFileIDSize(SM.getFileID(Loc)) -
SM.getFileOffset(Loc));
return SM.getLocForEndOfFile(SM.getFileID(Loc));
}
/// Find out where a macro is expanded. If the immediate result is a
/// <scratch space>, keep looking until the result isn't. Return a pair of
/// \c SourceLocation. The first object is always the begin sloc of found
/// result. The second should be checked by the caller: if it has value, it's
/// the end sloc of the found result. Otherwise the while loop didn't get
/// executed, which means the location wasn't changed and the caller has to
/// learn the end sloc from somewhere else.
std::pair<SourceLocation, std::optional<SourceLocation>>
getNonScratchExpansionLoc(SourceLocation Loc) {
std::optional<SourceLocation> EndLoc = std::nullopt;
while (Loc.isMacroID() &&
SM.isWrittenInScratchSpace(SM.getSpellingLoc(Loc))) {
auto ExpansionRange = SM.getImmediateExpansionRange(Loc);
Loc = ExpansionRange.getBegin();
EndLoc = ExpansionRange.getEnd();
}
return std::make_pair(Loc, EndLoc);
}
/// Find out where the current file is included or macro is expanded. If
/// \c AcceptScratch is set to false, keep looking for expansions until the
/// found sloc is not a <scratch space>.
SourceLocation getIncludeOrExpansionLoc(SourceLocation Loc,
bool AcceptScratch = true) {
if (!Loc.isMacroID())
return SM.getIncludeLoc(SM.getFileID(Loc));
Loc = SM.getImmediateExpansionRange(Loc).getBegin();
if (AcceptScratch)
return Loc;
return getNonScratchExpansionLoc(Loc).first;
}
/// Return true if \c Loc is a location in a built-in macro.
bool isInBuiltin(SourceLocation Loc) {
return SM.getBufferName(SM.getSpellingLoc(Loc)) == "<built-in>";
}
/// Check whether \c Loc is included or expanded from \c Parent.
bool isNestedIn(SourceLocation Loc, FileID Parent) {
do {
Loc = getIncludeOrExpansionLoc(Loc);
if (Loc.isInvalid())
return false;
} while (!SM.isInFileID(Loc, Parent));
return true;
}
/// Get the start of \c S ignoring macro arguments and builtin macros.
SourceLocation getStart(const Stmt *S) {
SourceLocation Loc = S->getBeginLoc();
while (SM.isMacroArgExpansion(Loc) || isInBuiltin(Loc))
Loc = SM.getImmediateExpansionRange(Loc).getBegin();
return Loc;
}
/// Get the end of \c S ignoring macro arguments and builtin macros.
SourceLocation getEnd(const Stmt *S) {
SourceLocation Loc = S->getEndLoc();
while (SM.isMacroArgExpansion(Loc) || isInBuiltin(Loc))
Loc = SM.getImmediateExpansionRange(Loc).getBegin();
return getPreciseTokenLocEnd(Loc);
}
/// Find the set of files we have regions for and assign IDs
///
/// Fills \c Mapping with the virtual file mapping needed to write out
/// coverage and collects the necessary file information to emit source and
/// expansion regions.
void gatherFileIDs(SmallVectorImpl<unsigned> &Mapping) {
FileIDMapping.clear();
llvm::SmallSet<FileID, 8> Visited;
SmallVector<std::pair<SourceLocation, unsigned>, 8> FileLocs;
for (auto &Region : SourceRegions) {
SourceLocation Loc = Region.getBeginLoc();
// Replace Region with its definition if it is in <scratch space>.
auto NonScratchExpansionLoc = getNonScratchExpansionLoc(Loc);
auto EndLoc = NonScratchExpansionLoc.second;
if (EndLoc.has_value()) {
Loc = NonScratchExpansionLoc.first;
Region.setStartLoc(Loc);
Region.setEndLoc(EndLoc.value());
}
// Replace Loc with FileLoc if it is expanded with system headers.
if (!SystemHeadersCoverage && SM.isInSystemMacro(Loc)) {
auto BeginLoc = SM.getSpellingLoc(Loc);
auto EndLoc = SM.getSpellingLoc(Region.getEndLoc());
if (SM.isWrittenInSameFile(BeginLoc, EndLoc)) {
Loc = SM.getFileLoc(Loc);
Region.setStartLoc(Loc);
Region.setEndLoc(SM.getFileLoc(Region.getEndLoc()));
}
}
FileID File = SM.getFileID(Loc);
if (!Visited.insert(File).second)
continue;
assert(SystemHeadersCoverage ||
!SM.isInSystemHeader(SM.getSpellingLoc(Loc)));
unsigned Depth = 0;
for (SourceLocation Parent = getIncludeOrExpansionLoc(Loc);
Parent.isValid(); Parent = getIncludeOrExpansionLoc(Parent))
++Depth;
FileLocs.push_back(std::make_pair(Loc, Depth));
}
llvm::stable_sort(FileLocs, llvm::less_second());
for (const auto &FL : FileLocs) {
SourceLocation Loc = FL.first;
FileID SpellingFile = SM.getDecomposedSpellingLoc(Loc).first;
auto Entry = SM.getFileEntryRefForID(SpellingFile);
if (!Entry)
continue;
FileIDMapping[SM.getFileID(Loc)] = std::make_pair(Mapping.size(), Loc);
Mapping.push_back(CVM.getFileID(*Entry));
}
}
/// Get the coverage mapping file ID for \c Loc.
///
/// If such file id doesn't exist, return std::nullopt.
std::optional<unsigned> getCoverageFileID(SourceLocation Loc) {
auto Mapping = FileIDMapping.find(SM.getFileID(Loc));
if (Mapping != FileIDMapping.end())
return Mapping->second.first;
return std::nullopt;
}
/// This shrinks the skipped range if it spans a line that contains a
/// non-comment token. If shrinking the skipped range would make it empty,
/// this returns std::nullopt.
/// Note this function can potentially be expensive because
/// getSpellingLineNumber uses getLineNumber, which is expensive.
std::optional<SpellingRegion> adjustSkippedRange(SourceManager &SM,
SourceLocation LocStart,
SourceLocation LocEnd,
SourceLocation PrevTokLoc,
SourceLocation NextTokLoc) {
SpellingRegion SR{SM, LocStart, LocEnd};
SR.ColumnStart = 1;
if (PrevTokLoc.isValid() && SM.isWrittenInSameFile(LocStart, PrevTokLoc) &&
SR.LineStart == SM.getSpellingLineNumber(PrevTokLoc))
SR.LineStart++;
if (NextTokLoc.isValid() && SM.isWrittenInSameFile(LocEnd, NextTokLoc) &&
SR.LineEnd == SM.getSpellingLineNumber(NextTokLoc)) {
SR.LineEnd--;
SR.ColumnEnd++;
}
if (SR.isInSourceOrder())
return SR;
return std::nullopt;
}
/// Gather all the regions that were skipped by the preprocessor
/// using the constructs like #if or comments.
void gatherSkippedRegions() {
/// An array of the minimum lineStarts and the maximum lineEnds
/// for mapping regions from the appropriate source files.
llvm::SmallVector<std::pair<unsigned, unsigned>, 8> FileLineRanges;
FileLineRanges.resize(
FileIDMapping.size(),
std::make_pair(std::numeric_limits<unsigned>::max(), 0));
for (const auto &R : MappingRegions) {
FileLineRanges[R.FileID].first =
std::min(FileLineRanges[R.FileID].first, R.LineStart);
FileLineRanges[R.FileID].second =
std::max(FileLineRanges[R.FileID].second, R.LineEnd);
}
auto SkippedRanges = CVM.getSourceInfo().getSkippedRanges();
for (auto &I : SkippedRanges) {
SourceRange Range = I.Range;
auto LocStart = Range.getBegin();
auto LocEnd = Range.getEnd();
assert(SM.isWrittenInSameFile(LocStart, LocEnd) &&
"region spans multiple files");
auto CovFileID = getCoverageFileID(LocStart);
if (!CovFileID)
continue;
std::optional<SpellingRegion> SR;
if (I.isComment())
SR = adjustSkippedRange(SM, LocStart, LocEnd, I.PrevTokLoc,
I.NextTokLoc);
else if (I.isPPIfElse() || I.isEmptyLine())
SR = {SM, LocStart, LocEnd};
if (!SR)
continue;
auto Region = CounterMappingRegion::makeSkipped(
*CovFileID, SR->LineStart, SR->ColumnStart, SR->LineEnd,
SR->ColumnEnd);
// Make sure that we only collect the regions that are inside
// the source code of this function.
if (Region.LineStart >= FileLineRanges[*CovFileID].first &&
Region.LineEnd <= FileLineRanges[*CovFileID].second)
MappingRegions.push_back(Region);
}
}
/// Generate the coverage counter mapping regions from collected
/// source regions.
void emitSourceRegions(const SourceRegionFilter &Filter) {
for (const auto &Region : SourceRegions) {
assert(Region.hasEndLoc() && "incomplete region");
SourceLocation LocStart = Region.getBeginLoc();
assert(SM.getFileID(LocStart).isValid() && "region in invalid file");
// Ignore regions from system headers unless collecting coverage from
// system headers is explicitly enabled.
if (!SystemHeadersCoverage &&
SM.isInSystemHeader(SM.getSpellingLoc(LocStart))) {
assert(!Region.isMCDCBranch() && !Region.isMCDCDecision() &&
"Don't suppress the condition in system headers");
continue;
}
auto CovFileID = getCoverageFileID(LocStart);
// Ignore regions that don't have a file, such as builtin macros.
if (!CovFileID) {
assert(!Region.isMCDCBranch() && !Region.isMCDCDecision() &&
"Don't suppress the condition in non-file regions");
continue;
}
SourceLocation LocEnd = Region.getEndLoc();
assert(SM.isWrittenInSameFile(LocStart, LocEnd) &&
"region spans multiple files");
// Don't add code regions for the area covered by expansion regions.
// This not only suppresses redundant regions, but sometimes prevents
// creating regions with wrong counters if, for example, a statement's
// body ends at the end of a nested macro.
if (Filter.count(std::make_pair(LocStart, LocEnd))) {
assert(!Region.isMCDCBranch() && !Region.isMCDCDecision() &&
"Don't suppress the condition");
continue;
}
// Find the spelling locations for the mapping region.
SpellingRegion SR{SM, LocStart, LocEnd};
assert(SR.isInSourceOrder() && "region start and end out of order");
if (Region.isGap()) {
MappingRegions.push_back(CounterMappingRegion::makeGapRegion(
Region.getCounter(), *CovFileID, SR.LineStart, SR.ColumnStart,
SR.LineEnd, SR.ColumnEnd));
} else if (Region.isSkipped()) {
MappingRegions.push_back(CounterMappingRegion::makeSkipped(
*CovFileID, SR.LineStart, SR.ColumnStart, SR.LineEnd,
SR.ColumnEnd));
} else if (Region.isBranch()) {
MappingRegions.push_back(CounterMappingRegion::makeBranchRegion(
Region.getCounter(), Region.getFalseCounter(), *CovFileID,
SR.LineStart, SR.ColumnStart, SR.LineEnd, SR.ColumnEnd,
Region.getMCDCParams()));
} else if (Region.isMCDCDecision()) {
MappingRegions.push_back(CounterMappingRegion::makeDecisionRegion(
Region.getMCDCDecisionParams(), *CovFileID, SR.LineStart,
SR.ColumnStart, SR.LineEnd, SR.ColumnEnd));
} else {
MappingRegions.push_back(CounterMappingRegion::makeRegion(
Region.getCounter(), *CovFileID, SR.LineStart, SR.ColumnStart,
SR.LineEnd, SR.ColumnEnd));
}
}
}
/// Generate expansion regions for each virtual file we've seen.
SourceRegionFilter emitExpansionRegions() {
SourceRegionFilter Filter;
for (const auto &FM : FileIDMapping) {
SourceLocation ExpandedLoc = FM.second.second;
SourceLocation ParentLoc = getIncludeOrExpansionLoc(ExpandedLoc, false);
if (ParentLoc.isInvalid())
continue;
auto ParentFileID = getCoverageFileID(ParentLoc);
if (!ParentFileID)
continue;
auto ExpandedFileID = getCoverageFileID(ExpandedLoc);
assert(ExpandedFileID && "expansion in uncovered file");
SourceLocation LocEnd = getPreciseTokenLocEnd(ParentLoc);
assert(SM.isWrittenInSameFile(ParentLoc, LocEnd) &&
"region spans multiple files");
Filter.insert(std::make_pair(ParentLoc, LocEnd));
SpellingRegion SR{SM, ParentLoc, LocEnd};
assert(SR.isInSourceOrder() && "region start and end out of order");
MappingRegions.push_back(CounterMappingRegion::makeExpansion(
*ParentFileID, *ExpandedFileID, SR.LineStart, SR.ColumnStart,
SR.LineEnd, SR.ColumnEnd));
}
return Filter;
}
};
/// Creates unreachable coverage regions for the functions that
/// are not emitted.
struct EmptyCoverageMappingBuilder : public CoverageMappingBuilder {
EmptyCoverageMappingBuilder(CoverageMappingModuleGen &CVM, SourceManager &SM,
const LangOptions &LangOpts)
: CoverageMappingBuilder(CVM, SM, LangOpts) {}
void VisitDecl(const Decl *D) {
if (!D->hasBody())
return;
auto Body = D->getBody();
SourceLocation Start = getStart(Body);
SourceLocation End = getEnd(Body);
if (!SM.isWrittenInSameFile(Start, End)) {
// Walk up to find the common ancestor.
// Correct the locations accordingly.
FileID StartFileID = SM.getFileID(Start);
FileID EndFileID = SM.getFileID(End);
while (StartFileID != EndFileID && !isNestedIn(End, StartFileID)) {
Start = getIncludeOrExpansionLoc(Start);
assert(Start.isValid() &&
"Declaration start location not nested within a known region");
StartFileID = SM.getFileID(Start);
}
while (StartFileID != EndFileID) {
End = getPreciseTokenLocEnd(getIncludeOrExpansionLoc(End));
assert(End.isValid() &&
"Declaration end location not nested within a known region");
EndFileID = SM.getFileID(End);
}
}
SourceRegions.emplace_back(Counter(), Start, End);
}
/// Write the mapping data to the output stream
void write(llvm::raw_ostream &OS) {
SmallVector<unsigned, 16> FileIDMapping;
gatherFileIDs(FileIDMapping);
emitSourceRegions(SourceRegionFilter());
if (MappingRegions.empty())
return;
CoverageMappingWriter Writer(FileIDMapping, {}, MappingRegions);
Writer.write(OS);
}
};
/// A wrapper object for maintaining stacks to track the resursive AST visitor
/// walks for the purpose of assigning IDs to leaf-level conditions measured by
/// MC/DC. The object is created with a reference to the MCDCBitmapMap that was
/// created during the initial AST walk. The presence of a bitmap associated
/// with a boolean expression (top-level logical operator nest) indicates that
/// the boolean expression qualified for MC/DC. The resulting condition IDs
/// are preserved in a map reference that is also provided during object
/// creation.
struct MCDCCoverageBuilder {
/// The AST walk recursively visits nested logical-AND or logical-OR binary
/// operator nodes and then visits their LHS and RHS children nodes. As this
/// happens, the algorithm will assign IDs to each operator's LHS and RHS side
/// as the walk moves deeper into the nest. At each level of the recursive
/// nest, the LHS and RHS may actually correspond to larger subtrees (not
/// leaf-conditions). If this is the case, when that node is visited, the ID
/// assigned to the subtree is re-assigned to its LHS, and a new ID is given
/// to its RHS. At the end of the walk, all leaf-level conditions will have a
/// unique ID -- keep in mind that the final set of IDs may not be in
/// numerical order from left to right.
///
/// Example: "x = (A && B) || (C && D) || (D && F)"
///
/// Visit Depth1:
/// (A && B) || (C && D) || (D && F)
/// ^-------LHS--------^ ^-RHS--^
/// ID=1 ID=2
///
/// Visit LHS-Depth2:
/// (A && B) || (C && D)
/// ^-LHS--^ ^-RHS--^
/// ID=1 ID=3
///
/// Visit LHS-Depth3:
/// (A && B)
/// LHS RHS
/// ID=1 ID=4
///
/// Visit RHS-Depth3:
/// (C && D)
/// LHS RHS
/// ID=3 ID=5
///
/// Visit RHS-Depth2: (D && F)
/// LHS RHS
/// ID=2 ID=6
///
/// Visit Depth1:
/// (A && B) || (C && D) || (D && F)
/// ID=1 ID=4 ID=3 ID=5 ID=2 ID=6
///
/// A node ID of '0' always means MC/DC isn't being tracked.
///
/// As the AST walk proceeds recursively, the algorithm will also use a stack
/// to track the IDs of logical-AND and logical-OR operations on the RHS so
/// that it can be determined which nodes are executed next, depending on how
/// a LHS or RHS of a logical-AND or logical-OR is evaluated. This
/// information relies on the assigned IDs and are embedded within the
/// coverage region IDs of each branch region associated with a leaf-level
/// condition. This information helps the visualization tool reconstruct all
/// possible test vectors for the purposes of MC/DC analysis. If a "next" node
/// ID is '0', it means it's the end of the test vector. The following rules
/// are used:
///
/// For logical-AND ("LHS && RHS"):
/// - If LHS is TRUE, execution goes to the RHS node.
/// - If LHS is FALSE, execution goes to the LHS node of the next logical-OR.
/// If that does not exist, execution exits (ID == 0).
///
/// - If RHS is TRUE, execution goes to LHS node of the next logical-AND.
/// If that does not exist, execution exits (ID == 0).
/// - If RHS is FALSE, execution goes to the LHS node of the next logical-OR.
/// If that does not exist, execution exits (ID == 0).
///
/// For logical-OR ("LHS || RHS"):
/// - If LHS is TRUE, execution goes to the LHS node of the next logical-AND.
/// If that does not exist, execution exits (ID == 0).
/// - If LHS is FALSE, execution goes to the RHS node.
///
/// - If RHS is TRUE, execution goes to LHS node of the next logical-AND.
/// If that does not exist, execution exits (ID == 0).
/// - If RHS is FALSE, execution goes to the LHS node of the next logical-OR.
/// If that does not exist, execution exits (ID == 0).
///
/// Finally, the condition IDs are also used when instrumenting the code to
/// indicate a unique offset into a temporary bitmap that represents the true
/// or false evaluation of that particular condition.
///
/// NOTE regarding the use of CodeGenFunction::stripCond(). Even though, for
/// simplicity, parentheses and unary logical-NOT operators are considered
/// part of their underlying condition for both MC/DC and branch coverage, the
/// condition IDs themselves are assigned and tracked using the underlying
/// condition itself. This is done solely for consistency since parentheses
/// and logical-NOTs are ignored when checking whether the condition is
/// actually an instrumentable condition. This can also make debugging a bit
/// easier.
private:
CodeGenModule &CGM;
llvm::SmallVector<mcdc::ConditionIDs> DecisionStack;
MCDC::State &MCDCState;
const Stmt *DecisionStmt = nullptr;
mcdc::ConditionID NextID = 0;
bool NotMapped = false;
/// Represent a sentinel value as a pair of final decisions for the bottom
// of DecisionStack.
static constexpr mcdc::ConditionIDs DecisionStackSentinel{-1, -1};
/// Is this a logical-AND operation?
bool isLAnd(const BinaryOperator *E) const {
return E->getOpcode() == BO_LAnd;
}
public:
MCDCCoverageBuilder(CodeGenModule &CGM, MCDC::State &MCDCState)
: CGM(CGM), DecisionStack(1, DecisionStackSentinel),
MCDCState(MCDCState) {}
/// Return whether the build of the control flow map is at the top-level
/// (root) of a logical operator nest in a boolean expression prior to the
/// assignment of condition IDs.
bool isIdle() const { return (NextID == 0 && !NotMapped); }
/// Return whether any IDs have been assigned in the build of the control
/// flow map, indicating that the map is being generated for this boolean
/// expression.
bool isBuilding() const { return (NextID > 0); }
/// Set the given condition's ID.
void setCondID(const Expr *Cond, mcdc::ConditionID ID) {
MCDCState.BranchByStmt[CodeGenFunction::stripCond(Cond)] = {ID,
DecisionStmt};
}
/// Return the ID of a given condition.
mcdc::ConditionID getCondID(const Expr *Cond) const {
auto I = MCDCState.BranchByStmt.find(CodeGenFunction::stripCond(Cond));
if (I == MCDCState.BranchByStmt.end())
return -1;
else
return I->second.ID;
}
/// Return the LHS Decision ([0,0] if not set).
const mcdc::ConditionIDs &back() const { return DecisionStack.back(); }
/// Push the binary operator statement to track the nest level and assign IDs
/// to the operator's LHS and RHS. The RHS may be a larger subtree that is
/// broken up on successive levels.
void pushAndAssignIDs(const BinaryOperator *E) {
if (!CGM.getCodeGenOpts().MCDCCoverage)
return;
// If binary expression is disqualified, don't do mapping.
if (!isBuilding() &&
!MCDCState.DecisionByStmt.contains(CodeGenFunction::stripCond(E)))
NotMapped = true;
// Don't go any further if we don't need to map condition IDs.
if (NotMapped)
return;
if (NextID == 0) {
DecisionStmt = E;
assert(MCDCState.DecisionByStmt.contains(E));
}
const mcdc::ConditionIDs &ParentDecision = DecisionStack.back();
// If the operator itself has an assigned ID, this means it represents a
// larger subtree. In this case, assign that ID to its LHS node. Its RHS
// will receive a new ID below. Otherwise, assign ID+1 to LHS.
if (MCDCState.BranchByStmt.contains(CodeGenFunction::stripCond(E)))
setCondID(E->getLHS(), getCondID(E));
else
setCondID(E->getLHS(), NextID++);
// Assign a ID+1 for the RHS.
mcdc::ConditionID RHSid = NextID++;
setCondID(E->getRHS(), RHSid);
// Push the LHS decision IDs onto the DecisionStack.
if (isLAnd(E))
DecisionStack.push_back({ParentDecision[false], RHSid});
else
DecisionStack.push_back({RHSid, ParentDecision[true]});
}
/// Pop and return the LHS Decision ([0,0] if not set).
mcdc::ConditionIDs pop() {
if (!CGM.getCodeGenOpts().MCDCCoverage || NotMapped)
return DecisionStackSentinel;
assert(DecisionStack.size() > 1);
return DecisionStack.pop_back_val();
}
/// Return the total number of conditions and reset the state. The number of
/// conditions is zero if the expression isn't mapped.
unsigned getTotalConditionsAndReset(const BinaryOperator *E) {
if (!CGM.getCodeGenOpts().MCDCCoverage)
return 0;
assert(!isIdle());
assert(DecisionStack.size() == 1);
// Reset state if not doing mapping.
if (NotMapped) {
NotMapped = false;
assert(NextID == 0);
return 0;
}
// Set number of conditions and reset.
unsigned TotalConds = NextID;
// Reset ID back to beginning.
NextID = 0;
return TotalConds;
}
};
/// A StmtVisitor that creates coverage mapping regions which map
/// from the source code locations to the PGO counters.
struct CounterCoverageMappingBuilder
: public CoverageMappingBuilder,
public ConstStmtVisitor<CounterCoverageMappingBuilder> {
/// The map of statements to count values.
llvm::DenseMap<const Stmt *, CounterPair> &CounterMap;
MCDC::State &MCDCState;
/// A stack of currently live regions.
llvm::SmallVector<SourceMappingRegion> RegionStack;
/// Set if the Expr should be handled as a leaf even if it is kind of binary
/// logical ops (&&, ||).
llvm::DenseSet<const Stmt *> LeafExprSet;
/// An object to manage MCDC regions.
MCDCCoverageBuilder MCDCBuilder;
CounterExpressionBuilder Builder;
/// A location in the most recently visited file or macro.
///
/// This is used to adjust the active source regions appropriately when
/// expressions cross file or macro boundaries.
SourceLocation MostRecentLocation;
/// Whether the visitor at a terminate statement.
bool HasTerminateStmt = false;
/// Gap region counter after terminate statement.
Counter GapRegionCounter;
/// Return a counter for the subtraction of \c RHS from \c LHS
Counter subtractCounters(Counter LHS, Counter RHS, bool Simplify = true) {
assert(!llvm::EnableSingleByteCoverage &&
"cannot add counters when single byte coverage mode is enabled");
return Builder.subtract(LHS, RHS, Simplify);
}
/// Return a counter for the sum of \c LHS and \c RHS.
Counter addCounters(Counter LHS, Counter RHS, bool Simplify = true) {
return Builder.add(LHS, RHS, Simplify);
}
Counter addCounters(Counter C1, Counter C2, Counter C3,
bool Simplify = true) {
return addCounters(addCounters(C1, C2, Simplify), C3, Simplify);
}
/// Return the region counter for the given statement.
///
/// This should only be called on statements that have a dedicated counter.
Counter getRegionCounter(const Stmt *S) {
return Counter::getCounter(CounterMap[S].Executed);
}
struct BranchCounterPair {
Counter Executed; ///< The Counter previously assigned.
Counter Skipped; ///< An expression (Parent-Executed), or equivalent to it.
};
/// Retrieve or assign the pair of Counter(s).
///
/// This returns BranchCounterPair {Executed, Skipped}.
/// Executed is the Counter associated with S assigned by an earlier
/// CounterMapping pass.
/// Skipped may be an expression (Executed - ParentCnt) or newly
/// assigned Counter in EnableSingleByteCoverage, as subtract
/// expressions are not available in this mode.
///
/// \param S Key to the CounterMap
/// \param ParentCnt The Counter representing how many times S is evaluated.
/// \param SkipCntForOld (To be removed later) Optional fake Counter
/// to override Skipped for adjustment of
/// expressions in the old behavior of
/// EnableSingleByteCoverage that is unaware of
/// Branch coverage.
BranchCounterPair
getBranchCounterPair(const Stmt *S, Counter ParentCnt,
std::optional<Counter> SkipCntForOld = std::nullopt) {
Counter ExecCnt = getRegionCounter(S);
// The old behavior of SingleByte is unaware of Branches.
// Will be pruned after the migration of SingleByte.
if (llvm::EnableSingleByteCoverage) {
assert(SkipCntForOld &&
"SingleByte must provide SkipCntForOld as a fake Skipped count.");
return {ExecCnt, *SkipCntForOld};
}
return {ExecCnt, Builder.subtract(ParentCnt, ExecCnt)};
}
bool IsCounterEqual(Counter OutCount, Counter ParentCount) {
if (OutCount == ParentCount)
return true;
return false;
}
/// Push a region onto the stack.
///
/// Returns the index on the stack where the region was pushed. This can be
/// used with popRegions to exit a "scope", ending the region that was pushed.
size_t pushRegion(Counter Count,
std::optional<SourceLocation> StartLoc = std::nullopt,
std::optional<SourceLocation> EndLoc = std::nullopt,
std::optional<Counter> FalseCount = std::nullopt,
const mcdc::Parameters &BranchParams = std::monostate()) {
if (StartLoc && !FalseCount) {
MostRecentLocation = *StartLoc;
}
// If either of these locations is invalid, something elsewhere in the
// compiler has broken.
assert((!StartLoc || StartLoc->isValid()) && "Start location is not valid");
assert((!EndLoc || EndLoc->isValid()) && "End location is not valid");
// However, we can still recover without crashing.