//===-- Debug.cpp - An easy way to add debug output to your code ----------===//
//
-// This file implements a handle way of adding debugging information to your
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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.
//
// can specify '-debug-only=foo' to enable JUST the debug information for the
// foo class.
//
-// When compiling in release mode, the -debug-* options and all code in DEBUG()
-// statements disappears, so it does not effect the runtime of the code.
+// When compiling without assertions, the -debug-* options and all code in
+// DEBUG() statements disappears, so it does not affect the runtime of the code.
//
//===----------------------------------------------------------------------===//
-#include "Support/Statistic.h"
-#include "Support/CommandLine.h"
+#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"
-bool DebugFlag; // DebugFlag - Exported boolean set by the -debug option
+#undef isCurrentDebugType
+#undef setCurrentDebugType
-namespace {
+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 setCurrentDebugType(const char *Type) {
+ CurrentDebugType->clear();
+ CurrentDebugType->push_back(Type);
+}
+
+} // 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.
- cl::opt<bool, true>
- Debug("debug", cl::desc("Enable debug output"), cl::Hidden,
- cl::location(DebugFlag));
-
- std::string CurrentDebugType;
- struct DebugOnlyOpt {
- void operator=(const std::string &Val) const {
- DebugFlag |= !Val.empty();
- CurrentDebugType = Val;
+
+// -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;
+ CurrentDebugType->push_back(Val);
+ }
+};
+
+}
+
+static DebugOnlyOpt DebugOnlyOptLoc;
+
+static cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
+DebugOnly("debug-only", cl::desc("Enable a specific type of debug output"),
+ 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().
}
- } DebugOnlyOptLoc;
+ } thestrm;
- cl::opt<DebugOnlyOpt, true, cl::parser<std::string> >
- DebugOnly("debug-only", cl::desc("Enable a specific type of debug output"),
- cl::Hidden, cl::value_desc("debug string"),
- cl::location(DebugOnlyOptLoc), cl::ValueRequired);
-#endif
+ return thestrm.strm;
}
-// isCurrentDebugType - 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) {
- return CurrentDebugType.empty() || DebugType == CurrentDebugType;
+#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;
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