Merge pull request #86158 from slavapestov/cs-arena-bytes

Sema: Convert solver arena usage into an always-on statistic

Author: slavapestov

include/swift/Basic/Statistics.def

@@ -187,6 +187,14 @@ FRONTEND_STATISTIC(Sema, NumCrossImportsChecked)
 /// Number of pairs of modules we've actually found cross-imports for.
 FRONTEND_STATISTIC(Sema, NumCrossImportsFound)
 
+/// Number of bytes allocated in the solver arena, summed across all
+/// constraint systems for all expressions.
+FRONTEND_STATISTIC(Sema, NumSolverBytesAllocated)
+
+/// Number of bytes allocated in the solver arena, maximum across all
+/// constraint systems for all expressions.
+FRONTEND_STATISTIC(Sema, MaxSolverBytesAllocated)
+
 /// Number of steps recorded in the trail while solving expression type
 /// constraints. A rough proxy for "how much work the expression
 /// type checker did".

include/swift/Sema/ConstraintSolverStats.def

@@ -18,7 +18,6 @@
 #  error #define CS_STATISTIC(Name, Description) before including
 #endif
 
-CS_STATISTIC(ASTBytesAllocated, "bytes allocated in solver arena")
 CS_STATISTIC(NumTypeVariablesBound, "# of type variables bound")
 CS_STATISTIC(NumTypeVariableBindings, "# of type variable bindings attempted")
 CS_STATISTIC(NumDisjunctions, "# of disjunctions explored")

include/swift/Sema/ConstraintSystem.h

@@ -2196,7 +2196,7 @@ class ConstraintSystem {
 
   llvm::DenseMap<Expr *, std::pair<unsigned, Expr *>> ExprWeights;
 
-  /// Allocator used for all of the related constraint systems.
+  /// Allocator used for data that is local to this constraint system.
   llvm::BumpPtrAllocator Allocator;
 
   /// Arena used for memory management of constraint-checker-related

lib/Sema/CSSolver.cpp

@@ -670,20 +670,27 @@ ConstraintSystem::SolverState::~SolverState() {
     CS.activateConstraint(constraint);
   }
 
+  auto &ctx = CS.getASTContext();
+
   // If global constraint debugging is off and we are finished logging the
   // current solution attempt, switch debugging back off.
-  const auto &tyOpts = CS.getASTContext().TypeCheckerOpts;
-  if (!tyOpts.DebugConstraintSolver &&
-      tyOpts.DebugConstraintSolverAttempt &&
-      tyOpts.DebugConstraintSolverAttempt == SolutionAttempt) {
+  if (!ctx.TypeCheckerOpts.DebugConstraintSolver &&
+      ctx.TypeCheckerOpts.DebugConstraintSolverAttempt &&
+      ctx.TypeCheckerOpts.DebugConstraintSolverAttempt == SolutionAttempt) {
     CS.Options -= ConstraintSystemFlags::DebugConstraints;
   }
 
   // This statistic is special because it's not a counter; we just update
   // it in one shot at the end.
-  ASTBytesAllocated = CS.getASTContext().getSolverMemory();
+  if (ctx.Stats) {
+    auto &counters = ctx.Stats->getFrontendCounters();
+    int64_t bytes = CS.getAllocator().getBytesAllocated();
+    counters.NumSolverBytesAllocated += bytes;
+    counters.MaxSolverBytesAllocated =
+        std::max(counters.MaxSolverBytesAllocated, bytes);
+  }
 
-  // Write our local statistics back to the overall statistics.
+  // Write our local debug statistics back to the overall debug statistics.
   #define CS_STATISTIC(Name, Description) JOIN2(Overall,Name) += Name;
   #include "swift/Sema/ConstraintSolverStats.def"