[llvm-mca] Avoid exposing index values in the MCA interfaces.

Summary:
This patch eliminates many places where we originally needed to  pass index
values to represent an instruction.  The index is still used as a key, in various parts of 
MCA.  I'm  not comfortable eliminating the index just yet.    By burying the index in
the instruction, we can avoid exposing that value in many places.

Eventually, we should consider removing the Instructions list in the Backend 
all together,   it's only used to hold and reclaim the memory for the allocated 
Instruction instances.  Instead we could pass around a smart pointer.  But that's
a separate discussion/patch.

Reviewers: andreadb, courbet, RKSimon

Reviewed By: andreadb

Subscribers: javed.absar, tschuett, gbedwell, llvm-commits

Differential Revision: https://reviews.llvm.org/D46367

llvm-svn: 331660

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/tools/llvm-mca/RetireControlUnit.cpp b/llvm/tools/llvm-mca/RetireControlUnit.cpp
index bd0fc28c6ba..da93c2c11c1 100644
--- a/llvm/tools/llvm-mca/RetireControlUnit.cpp
+++ b/llvm/tools/llvm-mca/RetireControlUnit.cpp
@@ -28,7 +28,7 @@ RetireControlUnit::RetireControlUnit(const llvm::MCSchedModel &SM,
 }
 
 // Reserves a number of slots, and returns a new token.
-unsigned RetireControlUnit::reserveSlot(unsigned Index, unsigned NumMicroOps) {
+unsigned RetireControlUnit::reserveSlot(const InstRef &IR, unsigned NumMicroOps) {
   assert(isAvailable(NumMicroOps));
   unsigned NormalizedQuantity =
       std::min(NumMicroOps, static_cast<unsigned>(Queue.size()));
@@ -37,7 +37,7 @@ unsigned RetireControlUnit::reserveSlot(unsigned Index, unsigned NumMicroOps) {
   // resources, they still consume one slot in the retire queue.
   NormalizedQuantity = std::max(NormalizedQuantity, 1U);
   unsigned TokenID = NextAvailableSlotIdx;
-  Queue[NextAvailableSlotIdx] = {Index, NormalizedQuantity, false};
+  Queue[NextAvailableSlotIdx] = {IR, NormalizedQuantity, false};
   NextAvailableSlotIdx += NormalizedQuantity;
   NextAvailableSlotIdx %= Queue.size();
   AvailableSlots -= NormalizedQuantity;
@@ -54,9 +54,10 @@ void RetireControlUnit::cycleEvent() {
       break;
     RUToken &Current = Queue[CurrentInstructionSlotIdx];
     assert(Current.NumSlots && "Reserved zero slots?");
+    assert(Current.IR.isValid() && "Invalid RUToken in the RCU queue.");
     if (!Current.Executed)
       break;
-    Owner->notifyInstructionRetired(Current.Index);
+    Owner->notifyInstructionRetired(Current.IR);
     CurrentInstructionSlotIdx += Current.NumSlots;
     CurrentInstructionSlotIdx %= Queue.size();
     AvailableSlots += Current.NumSlots;
@@ -66,7 +67,7 @@ void RetireControlUnit::cycleEvent() {
 
 void RetireControlUnit::onInstructionExecuted(unsigned TokenID) {
   assert(Queue.size() > TokenID);
-  assert(Queue[TokenID].Executed == false && Queue[TokenID].Index != ~0U);
+  assert(Queue[TokenID].Executed == false && Queue[TokenID].IR.isValid());
   Queue[TokenID].Executed = true;
 }