[Profiler] Increment closure body count prior to the prolog (#33946)

This fixes a 'SILBuilder has no valid insertion point' assertion failure
seen when compiling various projects from the source compat suite.

rdar://68759819

Author: vedantk

lib/SILGen/SILGenFunction.cpp

@@ -524,10 +524,10 @@ void SILGenFunction::emitClosure(AbstractClosureExpr *ace) {
   auto resultIfaceTy = ace->getResultType()->mapTypeOutOfContext();
   auto captureInfo = SGM.M.Types.getLoweredLocalCaptures(
     SILDeclRef(ace));
+  emitProfilerIncrement(ace);
   emitProlog(captureInfo, ace->getParameters(), /*selfParam=*/nullptr,
              ace, resultIfaceTy, ace->isBodyThrowing(), ace->getLoc());
   prepareEpilog(true, ace->isBodyThrowing(), CleanupLocation(ace));
-  emitProfilerIncrement(ace);
   if (auto *ce = dyn_cast<ClosureExpr>(ace)) {
     emitStmt(ce->getBody());
   } else {

test/Profiler/coverage_closure_returns_never.swift

@@ -0,0 +1,14 @@
+// RUN: %target-swift-frontend -Xllvm -sil-full-demangle -profile-generate -profile-coverage-mapping -emit-sil -module-name coverage_closure_returns_never %s | %FileCheck %s
+
+// CHECK-LABEL: closure #1 (Swift.Never) -> Swift.Never in coverage_closure_returns_never.closure_with_fatal_error(Swift.Array<Swift.Never>) -> ()
+// CHECK: builtin "int_instrprof_increment"
+// CHECK-NEXT: debug_value {{.*}} : $Never
+// CHECK-NEXT: unreachable
+
+func closure_with_fatal_error(_ arr: [Never]) {
+// CHECK-LABEL: sil_coverage_map {{.*}}// closure #1 (Swift.Never) -> Swift.Never
+// CHECK-NEXT: [[@LINE+1]]:11 -> [[@LINE+3]]:4
+  arr.map {
+    _ in fatalError()
+  }
+}