Emit line table entries for colusure setup instructions.

Currently the Swift compiler makes these instructions with SILLocations marked
as autgenerated. While this allows for somewhat smoother stepping in some cases,
it can also make some debugging tasks harder due to missing source location
information, for example, when attributing memory allocations.

This patch makes these locations available again, based on that a debug info
consumer could consider filtering them out by recognizing that a source location
is on the opening `{` of a closure, but inside the scope of the function the
closure is defined in.

rdar://127095833

Author: adrian-prantl

lib/SILGen/SILGenExpr.cpp

@@ -3021,9 +3021,8 @@ RValueEmitter::emitClosureReference(AbstractClosureExpr *e,
 
   // Generate the closure value (if any) for the closure expr's function
   // reference.
-  SILLocation L = e;
-  L.markAutoGenerated();
-  return SGF.emitClosureValue(L, SILDeclRef(e), contextInfo, subs);
+  SILLocation loc = e;
+  return SGF.emitClosureValue(loc, SILDeclRef(e), contextInfo, subs);
 }
 
 RValue RValueEmitter::

test/DebugInfo/linetable-assign.swift

@@ -4,13 +4,13 @@
 public func g<T>(_ t: T) {}
 public func f(_ i: Int32) {
   // CHECK: function_ref @$s4main1fyys5Int32VFyycfU_
-  // CHECK-SAME: loc * "{{.*}}":13:3,
+  // CHECK-SAME: loc "{{.*}}":13:3,
   // CHECK: %[[CLOSURE:.*]] = partial_apply
-  // CHECK-SAME: loc * "{{.*}}":13:3,{{.*}}auto_gen
+  // CHECK-SAME: loc "{{.*}}":13:3,
   // CHECK: store %[[CLOSURE]]
-  // CHECK-SAME: loc "{{.*}}":13:3,  
+  // CHECK-SAME: loc "{{.*}}":13:3,
   var closure = // line 12
-  { // FIXME: Shoudll the store be associated with line 12?
+  {
     g(i)
   }
   return closure() 

test/SILGen/sil_locations.swift

@@ -213,7 +213,7 @@ func captures_tuple<T, U>(x: (T, U)) -> () -> (T, U) {
   // CHECK-LABEL: sil hidden [ossa] @$s13sil_locations14captures_tuple{{[_0-9a-zA-Z]*}}F
   // CHECK: tuple_element_addr {{.*}}, loc "{{.*}}":[[@LINE-3]]:27
   // CHECK: copy_addr {{.*}}, loc "{{.*}}":[[@LINE-4]]:27
-  // CHECK: function_ref {{.*}}, loc * "{{.*}}":[[@LINE-4]]:10
+  // CHECK: function_ref {{.*}}, loc "{{.*}}":[[@LINE-4]]:10
 
   // CHECK-LABEL: sil private [ossa] @$s13sil_locations14captures_tuple{{.*}}fU_
   // CHECK: copy_addr {{.*}}, loc "{{.*}}":[[@LINE-7]]:11