Reformat.

[oota-llvm.git] / include / llvm / CodeGen / ScheduleHazardRecognizer.h

diff --git a/include/llvm/CodeGen/ScheduleHazardRecognizer.h b/include/llvm/CodeGen/ScheduleHazardRecognizer.h
index 5cf45f7a99d3cd43eeb245ce8ad27dc7ae6809d1..8a40e7212ff6d37e3bf7ae7014dea552b9ea20eb 100644 (file)
--- a/include/llvm/CodeGen/ScheduleHazardRecognizer.h
+++ b/include/llvm/CodeGen/ScheduleHazardRecognizer.h
@@ -23,7 +23,15 @@ class SUnit;
 /// issued this cycle, and whether or not a noop needs to be inserted to handle
 /// the hazard.
 class ScheduleHazardRecognizer {
+protected:
+  /// MaxLookAhead - Indicate the number of cycles in the scoreboard
+  /// state. Important to restore the state after backtracking. Additionally,
+  /// MaxLookAhead=0 identifies a fake recognizer, allowing the client to
+  /// bypass virtual calls. Currently the PostRA scheduler ignores it.
+  unsigned MaxLookAhead;
+
 public:
+  ScheduleHazardRecognizer(): MaxLookAhead(0) {}
   virtual ~ScheduleHazardRecognizer();
 
   enum HazardType {
@@ -32,6 +40,16 @@ public:
     NoopHazard     // This instruction can't be emitted, and needs noops.
   };
 
+  unsigned getMaxLookAhead() const { return MaxLookAhead; }
+
+  bool isEnabled() const { return MaxLookAhead != 0; }
+
+  /// atIssueLimit - Return true if no more instructions may be issued in this
+  /// cycle.
+  ///
+  /// FIXME: remove this once MachineScheduler is the only client.
+  virtual bool atIssueLimit() const { return false; }
+
   /// getHazardType - Return the hazard type of emitting this node.  There are
   /// three possible results.  Either:
   ///  * NoHazard: it is legal to issue this instruction on this cycle.
@@ -39,23 +57,53 @@ public:
   ///     other instruction is available, issue it first.
   ///  * NoopHazard: issuing this instruction would break the program.  If
   ///     some other instruction can be issued, do so, otherwise issue a noop.
-  virtual HazardType getHazardType(SUnit *) {
+  virtual HazardType getHazardType(SUnit *m, int Stalls = 0) {
     return NoHazard;
   }
 
+  /// Reset - This callback is invoked when a new block of
+  /// instructions is about to be schedule. The hazard state should be
+  /// set to an initialized state.
+  virtual void Reset() {}
+
   /// EmitInstruction - This callback is invoked when an instruction is
   /// emitted, to advance the hazard state.
   virtual void EmitInstruction(SUnit *) {}
 
-  /// AdvanceCycle - This callback is invoked when no instructions can be
-  /// issued on this cycle without a hazard.  This should increment the
+  /// PreEmitNoops - This callback is invoked prior to emitting an instruction.
+  /// It should return the number of noops to emit prior to the provided
+  /// instruction.
+  /// Note: This is only used during PostRA scheduling. EmitNoop is not called
+  /// for these noops.
+  virtual unsigned PreEmitNoops(SUnit *) {
+    return 0;
+  }
+
+  /// ShouldPreferAnother - This callback may be invoked if getHazardType
+  /// returns NoHazard. If, even though there is no hazard, it would be better to
+  /// schedule another available instruction, this callback should return true.
+  virtual bool ShouldPreferAnother(SUnit *) {
+    return false;
+  }
+
+  /// AdvanceCycle - This callback is invoked whenever the next top-down
+  /// instruction to be scheduled cannot issue in the current cycle, either
+  /// because of latency or resource conflicts.  This should increment the
   /// internal state of the hazard recognizer so that previously "Hazard"
   /// instructions will now not be hazards.
   virtual void AdvanceCycle() {}
 
+  /// RecedeCycle - This callback is invoked whenever the next bottom-up
+  /// instruction to be scheduled cannot issue in the current cycle, either
+  /// because of latency or resource conflicts.
+  virtual void RecedeCycle() {}
+
   /// EmitNoop - This callback is invoked when a noop was added to the
   /// instruction stream.
-  virtual void EmitNoop() {}
+  virtual void EmitNoop() {
+    // Default implementation: count it as a cycle.
+    AdvanceCycle();
+  }
 };
 
 }