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llvm-mirror/tools/llvm-cov/gcov.cpp
Fangrui Song adac7ac5fb [llvm-cov gcov] Don't require NUL terminator when reading files
.gcno, .gcda and source files can be modified while we are reading them. If the
concurrent modification of a file being read nullifies the NUL terminator
assumption, llvm-cov can trip over an assertion failure in MemoryBuffer::init.
This is not so rare - the source files can be in an editor and .gcda can be
written by an running process (if the process forks, when .gcda gets written is
probably more unpredictable).

There is no accompanying test because an assertion failure requires data
races with some involved setting.
2020-07-19 00:31:52 -07:00

167 lines
7.2 KiB
C++

//===- gcov.cpp - GCOV compatible LLVM coverage tool ----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// llvm-cov is a command line tools to analyze and report coverage information.
//
//===----------------------------------------------------------------------===//
#include "llvm/ProfileData/GCOV.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Errc.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/Path.h"
#include <system_error>
using namespace llvm;
static void reportCoverage(StringRef SourceFile, StringRef ObjectDir,
const std::string &InputGCNO,
const std::string &InputGCDA, bool DumpGCOV,
const GCOV::Options &Options) {
SmallString<128> CoverageFileStem(ObjectDir);
if (CoverageFileStem.empty()) {
// If no directory was specified with -o, look next to the source file.
CoverageFileStem = sys::path::parent_path(SourceFile);
sys::path::append(CoverageFileStem, sys::path::stem(SourceFile));
} else if (sys::fs::is_directory(ObjectDir))
// A directory name was given. Use it and the source file name.
sys::path::append(CoverageFileStem, sys::path::stem(SourceFile));
else
// A file was given. Ignore the source file and look next to this file.
sys::path::replace_extension(CoverageFileStem, "");
std::string GCNO = InputGCNO.empty()
? std::string(CoverageFileStem.str()) + ".gcno"
: InputGCNO;
std::string GCDA = InputGCDA.empty()
? std::string(CoverageFileStem.str()) + ".gcda"
: InputGCDA;
GCOVFile GF;
// Open .gcda and .gcda without requiring a NUL terminator. The concurrent
// modification may nullify the NUL terminator condition.
ErrorOr<std::unique_ptr<MemoryBuffer>> GCNO_Buff =
MemoryBuffer::getFileOrSTDIN(GCNO, -1, /*RequiresNullTerminator=*/false);
if (std::error_code EC = GCNO_Buff.getError()) {
errs() << GCNO << ": " << EC.message() << "\n";
return;
}
GCOVBuffer GCNO_GB(GCNO_Buff.get().get());
if (!GF.readGCNO(GCNO_GB)) {
errs() << "Invalid .gcno File!\n";
return;
}
ErrorOr<std::unique_ptr<MemoryBuffer>> GCDA_Buff =
MemoryBuffer::getFileOrSTDIN(GCDA, -1, /*RequiresNullTerminator=*/false);
if (std::error_code EC = GCDA_Buff.getError()) {
if (EC != errc::no_such_file_or_directory) {
errs() << GCDA << ": " << EC.message() << "\n";
return;
}
// Clear the filename to make it clear we didn't read anything.
GCDA = "-";
} else {
GCOVBuffer gcda_buf(GCDA_Buff.get().get());
if (!gcda_buf.readGCDAFormat())
errs() << GCDA << ":not a gcov data file\n";
else if (!GF.readGCDA(gcda_buf))
errs() << "Invalid .gcda File!\n";
}
if (DumpGCOV)
GF.print(errs());
FileInfo FI(Options);
GF.collectLineCounts(FI);
FI.print(llvm::outs(), SourceFile, GCNO, GCDA, GF);
}
int gcovMain(int argc, const char *argv[]) {
cl::list<std::string> SourceFiles(cl::Positional, cl::OneOrMore,
cl::desc("SOURCEFILE"));
cl::opt<bool> AllBlocks("a", cl::Grouping, cl::init(false),
cl::desc("Display all basic blocks"));
cl::alias AllBlocksA("all-blocks", cl::aliasopt(AllBlocks));
cl::opt<bool> BranchProb("b", cl::Grouping, cl::init(false),
cl::desc("Display branch probabilities"));
cl::alias BranchProbA("branch-probabilities", cl::aliasopt(BranchProb));
cl::opt<bool> BranchCount("c", cl::Grouping, cl::init(false),
cl::desc("Display branch counts instead "
"of percentages (requires -b)"));
cl::alias BranchCountA("branch-counts", cl::aliasopt(BranchCount));
cl::opt<bool> LongNames("l", cl::Grouping, cl::init(false),
cl::desc("Prefix filenames with the main file"));
cl::alias LongNamesA("long-file-names", cl::aliasopt(LongNames));
cl::opt<bool> FuncSummary("f", cl::Grouping, cl::init(false),
cl::desc("Show coverage for each function"));
cl::alias FuncSummaryA("function-summaries", cl::aliasopt(FuncSummary));
// Supported by gcov 4.9~8. gcov 9 (GCC r265587) removed --intermediate-format
// and -i was changed to mean --json-format. We consider this format still
// useful and support -i.
cl::opt<bool> Intermediate(
"intermediate-format", cl::init(false),
cl::desc("Output .gcov in intermediate text format"));
cl::alias IntermediateA("i", cl::desc("Alias for --intermediate-format"),
cl::Grouping, cl::NotHidden,
cl::aliasopt(Intermediate));
cl::opt<bool> NoOutput("n", cl::Grouping, cl::init(false),
cl::desc("Do not output any .gcov files"));
cl::alias NoOutputA("no-output", cl::aliasopt(NoOutput));
cl::opt<std::string> ObjectDir(
"o", cl::value_desc("DIR|FILE"), cl::init(""),
cl::desc("Find objects in DIR or based on FILE's path"));
cl::alias ObjectDirA("object-directory", cl::aliasopt(ObjectDir));
cl::alias ObjectDirB("object-file", cl::aliasopt(ObjectDir));
cl::opt<bool> PreservePaths("p", cl::Grouping, cl::init(false),
cl::desc("Preserve path components"));
cl::alias PreservePathsA("preserve-paths", cl::aliasopt(PreservePaths));
cl::opt<bool> UseStdout("t", cl::Grouping, cl::init(false),
cl::desc("Print to stdout"));
cl::alias UseStdoutA("stdout", cl::aliasopt(UseStdout));
cl::opt<bool> UncondBranch("u", cl::Grouping, cl::init(false),
cl::desc("Display unconditional branch info "
"(requires -b)"));
cl::alias UncondBranchA("unconditional-branches", cl::aliasopt(UncondBranch));
cl::opt<bool> HashFilenames("x", cl::Grouping, cl::init(false),
cl::desc("Hash long pathnames"));
cl::alias HashFilenamesA("hash-filenames", cl::aliasopt(HashFilenames));
cl::OptionCategory DebugCat("Internal and debugging options");
cl::opt<bool> DumpGCOV("dump", cl::init(false), cl::cat(DebugCat),
cl::desc("Dump the gcov file to stderr"));
cl::opt<std::string> InputGCNO("gcno", cl::cat(DebugCat), cl::init(""),
cl::desc("Override inferred gcno file"));
cl::opt<std::string> InputGCDA("gcda", cl::cat(DebugCat), cl::init(""),
cl::desc("Override inferred gcda file"));
cl::ParseCommandLineOptions(argc, argv, "LLVM code coverage tool\n");
GCOV::Options Options(AllBlocks, BranchProb, BranchCount, FuncSummary,
PreservePaths, UncondBranch, Intermediate, LongNames,
NoOutput, UseStdout, HashFilenames);
for (const auto &SourceFile : SourceFiles)
reportCoverage(SourceFile, ObjectDir, InputGCNO, InputGCDA, DumpGCOV,
Options);
return 0;
}