1 files changed, 80 insertions, 0 deletions
diff --git a/llvm/tools/llvm-mca/InstructionTables.cpp b/llvm/tools/llvm-mca/InstructionTables.cpp
new file mode 100644
index 00000000000..044b516db5d
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+++ b/llvm/tools/llvm-mca/InstructionTables.cpp
@@ -0,0 +1,80 @@
+//===--------------------- InstructionTables.cpp ----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+/// \file
+///
+/// This file implements method InstructionTables::run().
+/// Method run() prints a theoretical resource pressure distribution based on
+/// the information available in the scheduling model, and without running
+/// the backend pipeline.
+///
+//===----------------------------------------------------------------------===//
+
+#include "InstructionTables.h"
+
+namespace mca {
+
+using namespace llvm;
+
+using ResourceRef = std::pair<uint64_t, uint64_t>;
+
+void InstructionTables::run() {
+  ArrayRef<uint64_t> Masks = IB.getProcResourceMasks();
+  SmallVector<std::pair<ResourceRef, double>, 4> UsedResources;
+
+  // Create an instruction descriptor for every instruction in the sequence.
+  while (S.hasNext()) {
+    UsedResources.clear();
+    InstRef IR = S.peekNext();
+    std::unique_ptr<Instruction> Inst = IB.createInstruction(IR.first, *IR.second);
+    const InstrDesc &Desc = Inst->getDesc();
+    // Now identify the resources consumed by this instruction.
+    for (const std::pair<uint64_t, ResourceUsage> Resource : Desc.Resources) {
+      // Skip zero-cycle resources (i.e. unused resources).
+      if (!Resource.second.size())
+        continue;
+      double Cycles = static_cast<double>(Resource.second.size());
+      unsigned Index =
+          std::distance(Masks.begin(), std::find(Masks.begin(), Masks.end(),
+                                                 Resource.first));
+      const MCProcResourceDesc &ProcResource = *SM.getProcResource(Index);
+      unsigned NumUnits = ProcResource.NumUnits;
+      if (!ProcResource.SubUnitsIdxBegin) {
+        // The number of cycles consumed by each unit.
+        Cycles /= NumUnits;
+        for (unsigned I = 0, E = NumUnits; I < E; ++I) {
+          ResourceRef ResourceUnit = std::make_pair(Index, 1U << I);
+          UsedResources.emplace_back(std::make_pair(ResourceUnit, Cycles));
+        }
+        continue;
+      }
+
+      // This is a group. Obtain the set of resources contained in this
+      // group. Some of these resources may implement multiple units.
+      // Uniformly distribute Cycles across all of the units.
+      for (unsigned I1 = 0; I1 < NumUnits; ++I1) {
+        unsigned SubUnitIdx = ProcResource.SubUnitsIdxBegin[I1];
+        const MCProcResourceDesc &SubUnit = *SM.getProcResource(SubUnitIdx);
+        // Compute the number of cycles consumed by each resource unit.
+        double RUCycles = Cycles / (NumUnits * SubUnit.NumUnits);
+        for (unsigned I2 = 0, E2 = SubUnit.NumUnits; I2 < E2; ++I2) {
+          ResourceRef ResourceUnit = std::make_pair(SubUnitIdx, 1U << I2);
+          UsedResources.emplace_back(std::make_pair(ResourceUnit, RUCycles));
+        }
+      }
+    }
+
+    // Now send a fake instruction issued event to all the listeners.
+    HWInstructionIssuedEvent Event(IR.first, UsedResources);
+    for (HWEventListener *Listener : Listeners)
+      Listener->onInstructionEvent(Event);
+    S.updateNext();
+  }
+}
+
+} // namespace mca