lib/Support/CodeGenCoverage.cpp

   1 //===- lib/Support/CodeGenCoverage.cpp -------------------------------------==//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 /// \file
  10 /// This file implements the CodeGenCoverage class.
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/Support/CodeGenCoverage.h"
  14
  15 #include "llvm/Support/Endian.h"
  16 #include "llvm/Support/FileSystem.h"
  17 #include "llvm/Support/Mutex.h"
  18 #include "llvm/Support/ScopedPrinter.h"
  19 #include "llvm/Support/ToolOutputFile.h"
  20
  21 #if LLVM_ON_UNIX
  22 #include <unistd.h>
  23 #elif LLVM_ON_WIN32
  24 #include <windows.h>
  25 #endif
  26
  27 using namespace llvm;
  28
  29 static sys::SmartMutex<true> OutputMutex;
  30
  31 CodeGenCoverage::CodeGenCoverage() {}
  32
  33 void CodeGenCoverage::setCovered(uint64_t RuleID) {
  34   if (RuleCoverage.size() <= RuleID)
  35     RuleCoverage.resize(RuleID + 1, 0);
  36   RuleCoverage[RuleID] = true;
  37 }
  38
  39 bool CodeGenCoverage::isCovered(uint64_t RuleID) {
  40   if (RuleCoverage.size() <= RuleID)
  41     return false;
  42   return RuleCoverage[RuleID];
  43 }
  44
  45 bool CodeGenCoverage::parse(MemoryBuffer &Buffer, StringRef BackendName) {
  46   const char *CurPtr = Buffer.getBufferStart();
  47
  48   while (CurPtr != Buffer.getBufferEnd()) {
  49     // Read the backend name from the input.
  50     const char *LexedBackendName = CurPtr;
  51     while (*CurPtr++ != 0)
  52       ;
  53     if (CurPtr == Buffer.getBufferEnd())
  54       return false; // Data is invalid, expected rule id's to follow.
  55
  56     bool IsForThisBackend = BackendName.equals(LexedBackendName);
  57     while (CurPtr != Buffer.getBufferEnd()) {
  58       if (std::distance(CurPtr, Buffer.getBufferEnd()) < 8)
  59         return false; // Data is invalid. Not enough bytes for another rule id.
  60
  61       uint64_t RuleID = support::endian::read64(CurPtr, support::native);
  62       CurPtr += 8;
  63
  64       // ~0ull terminates the rule id list.
  65       if (RuleID == ~0ull)
  66         break;
  67
  68       // Anything else, is recorded or ignored depending on whether it's
  69       // intended for the backend we're interested in.
  70       if (IsForThisBackend)
  71         setCovered(RuleID);
  72     }
  73   }
  74
  75   return true;
  76 }
  77
  78 bool CodeGenCoverage::emit(StringRef CoveragePrefix,
  79                            StringRef BackendName) const {
  80   if (!CoveragePrefix.empty() && !RuleCoverage.empty()) {
  81     sys::SmartScopedLock<true> Lock(OutputMutex);
  82
  83     // We can handle locking within a process easily enough but we don't want to
  84     // manage it between multiple processes. Use the process ID to ensure no
  85     // more than one process is ever writing to the same file at the same time.
  86     std::string Pid =
  87 #if LLVM_ON_UNIX
  88         llvm::to_string(::getpid());
  89 #elif LLVM_ON_WIN32
  90         llvm::to_string(::GetCurrentProcessId());
  91 #else
  92         "";
  93 #endif
  94
  95     std::string CoverageFilename = (CoveragePrefix + Pid).str();
  96
  97     std::error_code EC;
  98     sys::fs::OpenFlags OpenFlags = sys::fs::F_Append;
  99     std::unique_ptr<ToolOutputFile> CoverageFile =
 100         llvm::make_unique<ToolOutputFile>(CoverageFilename, EC, OpenFlags);
 101     if (EC)
 102       return false;
 103
 104     uint64_t Zero = 0;
 105     uint64_t InvZero = ~0ull;
 106     CoverageFile->os() << BackendName;
 107     CoverageFile->os().write((const char *)&Zero, sizeof(unsigned char));
 108     for (uint64_t I : RuleCoverage.set_bits())
 109       CoverageFile->os().write((const char *)&I, sizeof(uint64_t));
 110     CoverageFile->os().write((const char *)&InvZero, sizeof(uint64_t));
 111
 112     CoverageFile->keep();
 113   }
 114
 115   return true;
 116 }
 117
 118 void CodeGenCoverage::reset() { RuleCoverage.resize(0); }