CSRanking: Check for timeouts during solution comparisons, which are time-consuming

Author: AnthonyLatsis

include/swift/Sema/ConstraintSystem.h

@@ -5646,7 +5646,7 @@ class ConstraintSystem {
     return false;
   }
 
-  bool isTooComplex(SmallVectorImpl<Solution> const &solutions) {
+  bool isTooComplex(ArrayRef<Solution> solutions) {
     if (isAlreadyTooComplex.first)
       return true;
 

lib/Sema/CSRanking.cpp

@@ -1453,6 +1453,10 @@ ConstraintSystem::findBestSolution(SmallVectorImpl<Solution> &viable,
       bestIdx = i;
       break;
     }
+
+    // Give up if we're out of time.
+    if (isTooComplex(/*solutions=*/{}))
+      return None;
   }
 
   // Make sure that our current best is better than all of the solved systems.
@@ -1483,6 +1487,10 @@ ConstraintSystem::findBestSolution(SmallVectorImpl<Solution> &viable,
       ambiguous = true;
       break;
     }
+
+    // Give up if we're out of time.
+    if (isTooComplex(/*solutions=*/{}))
+      return None;
   }
 
   // If the result was not ambiguous, we're done.