1 files changed, 124 insertions, 0 deletions
diff --git a/llvm/lib/Support/CodeGenCoverage.cpp b/llvm/lib/Support/CodeGenCoverage.cpp
new file mode 100644
index 000000000000..2db4193ce382
--- /dev/null
+++ b/llvm/lib/Support/CodeGenCoverage.cpp
@@ -0,0 +1,124 @@
+//===- lib/Support/CodeGenCoverage.cpp -------------------------------------==//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements the CodeGenCoverage class.
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/CodeGenCoverage.h"
+
+#include "llvm/Config/llvm-config.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Mutex.h"
+#include "llvm/Support/ScopedPrinter.h"
+#include "llvm/Support/ToolOutputFile.h"
+
+#if LLVM_ON_UNIX
+#include <unistd.h>
+#elif defined(_WIN32)
+#include <windows.h>
+#endif
+
+using namespace llvm;
+
+static sys::SmartMutex<true> OutputMutex;
+
+CodeGenCoverage::CodeGenCoverage() {}
+
+void CodeGenCoverage::setCovered(uint64_t RuleID) {
+  if (RuleCoverage.size() <= RuleID)
+    RuleCoverage.resize(RuleID + 1, 0);
+  RuleCoverage[RuleID] = true;
+}
+
+bool CodeGenCoverage::isCovered(uint64_t RuleID) const {
+  if (RuleCoverage.size() <= RuleID)
+    return false;
+  return RuleCoverage[RuleID];
+}
+
+iterator_range<CodeGenCoverage::const_covered_iterator>
+CodeGenCoverage::covered() const {
+  return RuleCoverage.set_bits();
+}
+
+bool CodeGenCoverage::parse(MemoryBuffer &Buffer, StringRef BackendName) {
+  const char *CurPtr = Buffer.getBufferStart();
+
+  while (CurPtr != Buffer.getBufferEnd()) {
+    // Read the backend name from the input.
+    const char *LexedBackendName = CurPtr;
+    while (*CurPtr++ != 0)
+      ;
+    if (CurPtr == Buffer.getBufferEnd())
+      return false; // Data is invalid, expected rule id's to follow.
+
+    bool IsForThisBackend = BackendName.equals(LexedBackendName);
+    while (CurPtr != Buffer.getBufferEnd()) {
+      if (std::distance(CurPtr, Buffer.getBufferEnd()) < 8)
+        return false; // Data is invalid. Not enough bytes for another rule id.
+
+      uint64_t RuleID = support::endian::read64(CurPtr, support::native);
+      CurPtr += 8;
+
+      // ~0ull terminates the rule id list.
+      if (RuleID == ~0ull)
+        break;
+
+      // Anything else, is recorded or ignored depending on whether it's
+      // intended for the backend we're interested in.
+      if (IsForThisBackend)
+        setCovered(RuleID);
+    }
+  }
+
+  return true;
+}
+
+bool CodeGenCoverage::emit(StringRef CoveragePrefix,
+                           StringRef BackendName) const {
+  if (!CoveragePrefix.empty() && !RuleCoverage.empty()) {
+    sys::SmartScopedLock<true> Lock(OutputMutex);
+
+    // We can handle locking within a process easily enough but we don't want to
+    // manage it between multiple processes. Use the process ID to ensure no
+    // more than one process is ever writing to the same file at the same time.
+    std::string Pid =
+#if LLVM_ON_UNIX
+        llvm::to_string(::getpid());
+#elif defined(_WIN32)
+        llvm::to_string(::GetCurrentProcessId());
+#else
+        "";
+#endif
+
+    std::string CoverageFilename = (CoveragePrefix + Pid).str();
+
+    std::error_code EC;
+    sys::fs::OpenFlags OpenFlags = sys::fs::OF_Append;
+    std::unique_ptr<ToolOutputFile> CoverageFile =
+        std::make_unique<ToolOutputFile>(CoverageFilename, EC, OpenFlags);
+    if (EC)
+      return false;
+
+    uint64_t Zero = 0;
+    uint64_t InvZero = ~0ull;
+    CoverageFile->os() << BackendName;
+    CoverageFile->os().write((const char *)&Zero, sizeof(unsigned char));
+    for (uint64_t I : RuleCoverage.set_bits())
+      CoverageFile->os().write((const char *)&I, sizeof(uint64_t));
+    CoverageFile->os().write((const char *)&InvZero, sizeof(uint64_t));
+
+    CoverageFile->keep();
+  }
+
+  return true;
+}
+
+void CodeGenCoverage::reset() { RuleCoverage.resize(0); }