1 files changed, 165 insertions, 0 deletions
diff --git a/llvm/lib/Support/Debug.cpp b/llvm/lib/Support/Debug.cpp
new file mode 100644
index 000000000000..737cd576ed80
--- /dev/null
+++ b/llvm/lib/Support/Debug.cpp
@@ -0,0 +1,165 @@
+//===-- Debug.cpp - An easy way to add debug output to your code ----------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a handy way of adding debugging information to your
+// code, without it being enabled all of the time, and without having to add
+// command line options to enable it.
+//
+// In particular, just wrap your code with the LLVM_DEBUG() macro, and it will
+// be enabled automatically if you specify '-debug' on the command-line.
+// Alternatively, you can also use the SET_DEBUG_TYPE("foo") macro to specify
+// that your debug code belongs to class "foo".  Then, on the command line, you
+// can specify '-debug-only=foo' to enable JUST the debug information for the
+// foo class.
+//
+// When compiling without assertions, the -debug-* options and all code in
+// LLVM_DEBUG() statements disappears, so it does not affect the runtime of the
+// code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/circular_raw_ostream.h"
+#include "llvm/Support/raw_ostream.h"
+
+#undef isCurrentDebugType
+#undef setCurrentDebugType
+#undef setCurrentDebugTypes
+
+using namespace llvm;
+
+// Even though LLVM might be built with NDEBUG, define symbols that the code
+// built without NDEBUG can depend on via the llvm/Support/Debug.h header.
+namespace llvm {
+/// Exported boolean set by the -debug option.
+bool DebugFlag = false;
+
+static ManagedStatic<std::vector<std::string>> CurrentDebugType;
+
+/// Return true if the specified string is the debug type
+/// specified on the command line, or if none was specified on the command line
+/// with the -debug-only=X option.
+bool isCurrentDebugType(const char *DebugType) {
+  if (CurrentDebugType->empty())
+    return true;
+  // See if DebugType is in list. Note: do not use find() as that forces us to
+  // unnecessarily create an std::string instance.
+  for (auto &d : *CurrentDebugType) {
+    if (d == DebugType)
+      return true;
+  }
+  return false;
+}
+
+/// Set the current debug type, as if the -debug-only=X
+/// option were specified.  Note that DebugFlag also needs to be set to true for
+/// debug output to be produced.
+///
+void setCurrentDebugTypes(const char **Types, unsigned Count);
+
+void setCurrentDebugType(const char *Type) {
+  setCurrentDebugTypes(&Type, 1);
+}
+
+void setCurrentDebugTypes(const char **Types, unsigned Count) {
+  CurrentDebugType->clear();
+  for (size_t T = 0; T < Count; ++T)
+    CurrentDebugType->push_back(Types[T]);
+}
+} // namespace llvm
+
+// All Debug.h functionality is a no-op in NDEBUG mode.
+#ifndef NDEBUG
+
+// -debug - Command line option to enable the DEBUG statements in the passes.
+// This flag may only be enabled in debug builds.
+static cl::opt<bool, true>
+Debug("debug", cl::desc("Enable debug output"), cl::Hidden,
+      cl::location(DebugFlag));
+
+// -debug-buffer-size - Buffer the last N characters of debug output
+//until program termination.
+static cl::opt<unsigned>
+DebugBufferSize("debug-buffer-size",
+                cl::desc("Buffer the last N characters of debug output "
+                         "until program termination. "
+                         "[default 0 -- immediate print-out]"),
+                cl::Hidden,
+                cl::init(0));
+
+namespace {
+
+struct DebugOnlyOpt {
+  void operator=(const std::string &Val) const {
+    if (Val.empty())
+      return;
+    DebugFlag = true;
+    SmallVector<StringRef,8> dbgTypes;
+    StringRef(Val).split(dbgTypes, ',', -1, false);
+    for (auto dbgType : dbgTypes)
+      CurrentDebugType->push_back(dbgType);
+  }
+};
+
+}
+
+static DebugOnlyOpt DebugOnlyOptLoc;
+
+static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
+DebugOnly("debug-only", cl::desc("Enable a specific type of debug output (comma separated list of types)"),
+          cl::Hidden, cl::ZeroOrMore, cl::value_desc("debug string"),
+          cl::location(DebugOnlyOptLoc), cl::ValueRequired);
+// Signal handlers - dump debug output on termination.
+static void debug_user_sig_handler(void *Cookie) {
+  // This is a bit sneaky.  Since this is under #ifndef NDEBUG, we
+  // know that debug mode is enabled and dbgs() really is a
+  // circular_raw_ostream.  If NDEBUG is defined, then dbgs() ==
+  // errs() but this will never be invoked.
+  llvm::circular_raw_ostream &dbgout =
+      static_cast<circular_raw_ostream &>(llvm::dbgs());
+  dbgout.flushBufferWithBanner();
+}
+
+/// dbgs - Return a circular-buffered debug stream.
+raw_ostream &llvm::dbgs() {
+  // Do one-time initialization in a thread-safe way.
+  static struct dbgstream {
+    circular_raw_ostream strm;
+
+    dbgstream() :
+        strm(errs(), "*** Debug Log Output ***\n",
+             (!EnableDebugBuffering || !DebugFlag) ? 0 : DebugBufferSize) {
+      if (EnableDebugBuffering && DebugFlag && DebugBufferSize != 0)
+        // TODO: Add a handler for SIGUSER1-type signals so the user can
+        // force a debug dump.
+        sys::AddSignalHandler(&debug_user_sig_handler, nullptr);
+      // Otherwise we've already set the debug stream buffer size to
+      // zero, disabling buffering so it will output directly to errs().
+    }
+  } thestrm;
+
+  return thestrm.strm;
+}
+
+#else
+// Avoid "has no symbols" warning.
+namespace llvm {
+  /// dbgs - Return errs().
+  raw_ostream &dbgs() {
+    return errs();
+  }
+}
+
+#endif
+
+/// EnableDebugBuffering - Turn on signal handler installation.
+///
+bool llvm::EnableDebugBuffering = false;