X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FDebug.cpp;h=d9cb8a9da8150c5a507ff5a89dfd7f63425b3698;hb=b9536ac581d0d74b29c11dcb33e22200b22b86b1;hp=50abe0164ac237297b7edd395ac6050ccca8f6c1;hpb=5aa638d8f78b556b9141f47d0895d001f80b0f09;p=oota-llvm.git

diff --git a/lib/Support/Debug.cpp b/lib/Support/Debug.cpp
index 50abe0164ac..d9cb8a9da81 100644
--- a/lib/Support/Debug.cpp
+++ b/lib/Support/Debug.cpp
@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file implements a handle way of adding debugging information to your
+// 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.
 //
@@ -18,13 +18,16 @@
 // 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 "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/circular_raw_ostream.h"
+
 using namespace llvm;
 
 // All Debug.h functionality is a no-op in NDEBUG mode.
@@ -37,19 +40,47 @@ 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));
+
 static std::string CurrentDebugType;
-static struct DebugOnlyOpt {
+
+namespace {
+
+struct DebugOnlyOpt {
   void operator=(const std::string &Val) const {
     DebugFlag |= !Val.empty();
     CurrentDebugType = Val;
   }
-} DebugOnlyOptLoc;
+};
+
+}
+
+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::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<llvm::circular_raw_ostream *>(&llvm::dbgs());
+  dbgout->flushBufferWithBanner();
+}
+
 // 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.
@@ -58,17 +89,46 @@ bool llvm::isCurrentDebugType(const char *DebugType) {
   return CurrentDebugType.empty() || DebugType == CurrentDebugType;
 }
 
-/// SetCurrentDebugType - Set the current debug type, as if the -debug-only=X
+/// setCurrentDebugType - 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 llvm::SetCurrentDebugType(const char *Type) {
+void llvm::setCurrentDebugType(const char *Type) {
   CurrentDebugType = Type;
 }
 
+/// 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, 0);
+      // 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 {
-int Debug_dummy = 0;
+  /// dbgs - Return errs().
+  raw_ostream &dbgs() {
+    return errs();
+  }
 }
+
 #endif
+
+/// EnableDebugBuffering - Turn on signal handler installation.
+///
+bool llvm::EnableDebugBuffering = false;