[llvm-mca] Add bottle-neck analysis to JSON output. (#90056)

This patch implements the bottle-neck analysis data in the JSON dump
mode.

2 files changed, 48 insertions, 1 deletions

diff --git a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp
index 409a701..ece5b67 100644
--- a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp
+++ b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.cpp
@@ -641,5 +641,51 @@ void BottleneckAnalysis::printView(raw_ostream &OS) const {
   printCriticalSequence(OS);
 }
 
+json::Value BottleneckAnalysis::toJSON() const {
+  if (!SeenStallCycles || !BPI.PressureIncreaseCycles) {
+    json::Object JO({{"PressureIncreaseCycles", 0}});
+    return JO;
+  }
+
+  json::Array CriticalSequence;
+  // get critical sequence
+  SmallVector<const DependencyEdge *, 16> Seq;
+  DG.getCriticalSequence(Seq);
+  if (!Seq.empty()) {
+    for (const DependencyEdge *&DE : Seq) {
+      json::Object DEJO({{"FromID", DE->FromIID},
+                         {"ToID", DE->ToIID},
+                         {"Type", static_cast<unsigned>(DE->Dep.Type)},
+                         {"ResourceOrRegID", DE->Dep.ResourceOrRegID}});
+      CriticalSequence.push_back(std::move(DEJO));
+    }
+  }
+
+  json::Array ResourcePressure;
+  if (BPI.PressureIncreaseCycles) {
+    ArrayRef<unsigned> Distribution = Tracker.getResourcePressureDistribution();
+    const MCSchedModel &SM = getSubTargetInfo().getSchedModel();
+    for (unsigned I = 0, E = Distribution.size(); I < E; ++I) {
+      unsigned ReleaseAtCycles = Distribution[I];
+      if (ReleaseAtCycles) {
+        const MCProcResourceDesc &PRDesc = *SM.getProcResource(I);
+        json::Object RPJO({{PRDesc.Name, ReleaseAtCycles}});
+        ResourcePressure.push_back(std::move(RPJO));
+      }
+    }
+  }
+
+  json::Object JO({{"PressureIncreaseCycles", BPI.PressureIncreaseCycles},
+                   {"ResourcePressureCycles", BPI.ResourcePressureCycles},
+                   {"DataDependencyCycles", BPI.DataDependencyCycles},
+                   {"RegisterDependencyCycles", BPI.RegisterDependencyCycles},
+                   {"MemoryDependencyCycles", BPI.MemoryDependencyCycles},
+                   {"TotalCycles", TotalCycles},
+                   {"DependencyEdge", std::move(CriticalSequence)},
+                   {"ResourcePressure", std::move(ResourcePressure)}});
+
+  return JO;
+}
+
 } // namespace mca.
 } // namespace llvm
diff --git a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h
index e709b25..529090c 100644
--- a/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h
+++ b/llvm/tools/llvm-mca/Views/BottleneckAnalysis.h
@@ -335,7 +335,8 @@ public:
 
   void printView(raw_ostream &OS) const override;
   StringRef getNameAsString() const override { return "BottleneckAnalysis"; }
-  bool isSerializable() const override { return false; }
+  bool isSerializable() const override { return true; }
+  json::Value toJSON() const override;
 
 #ifndef NDEBUG
   void dump(raw_ostream &OS, MCInstPrinter &MCIP) const { DG.dump(OS, MCIP); }