Disable the TrivialMoveOnlyTypeEliminator pass.

This fixes the `consuming` and `borrowing` keywords for some basic
cases. In particular, if a nontrivial struct contains a trivial 'let'
field, then this pass would result in invalid SIL types:

class C {}

struct BV {
  let p: UnsafeRawPointer
  let c: C
}

func getPointer(bv: consuming BV) -> UnsafeRawPointer {
  return bv.p
}

Ultimately, this pass makes sense, but there is something strange
about the way move-only-ness propagates into fields of aggregates
which needs to be fixed first. Until then, other features are blocked
on basic support for these keywords.

Fixes rdar://122701694 (`consuming` keyword causes verification error on invalid SIL types)

Author: atrick

lib/SILOptimizer/PassManager/PassPipeline.cpp

@@ -174,13 +174,22 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
   if (EnableDeinitDevirtualizer)
     P.addDeinitDevirtualizer();
 
+  // FIXME: rdar://122701694 (`consuming` keyword causes verification error on
+  //        invalid SIL types)
+  //
   // Lower move only wrapped trivial types.
-  P.addTrivialMoveOnlyTypeEliminator();
+  //   P.addTrivialMoveOnlyTypeEliminator();
+
   // Check no uses after consume operator of a value in an address.
   P.addConsumeOperatorCopyableAddressesChecker();
   // No uses after consume operator of copyable value.
   P.addConsumeOperatorCopyableValuesChecker();
 
+  // As a temporary measure, we also eliminate move only for non-trivial types
+  // until we can audit the later part of the pipeline. Eventually, this should
+  // occur before IRGen.
+  P.addMoveOnlyTypeEliminator();
+
   //
   // End Ownership Optimizations
   //===---
@@ -246,11 +255,6 @@ static void addMandatoryDiagnosticOptPipeline(SILPassPipelinePlan &P) {
   // Canonical swift requires all non cond_br critical edges to be split.
   P.addSplitNonCondBrCriticalEdges();
 
-  // As a temporary measure, we also eliminate move only for non-trivial types
-  // until we can audit the later part of the pipeline. Eventually, this should
-  // occur before IRGen.
-  P.addMoveOnlyTypeEliminator();
-
   // For embedded Swift: Specialize generic class vtables.
   P.addVTableSpecializer();
 

test/SILOptimizer/noimplicitcopy_consuming_parameters.swift

@@ -9,6 +9,7 @@ public class Klass {
 
 public struct NonTrivialStruct {
     var k = Klass()
+    let i = 0
 
     func doSomethingDefault() {}
     borrowing func doSomethingBorrowing() {}
@@ -230,6 +231,10 @@ func testLoadableConsumingCopyOperator(_ x: consuming NonTrivialStruct) {
     _ = copy x
 }
 
+func testLoadableConsumingTrivialLetField(_ x: consuming NonTrivialStruct) -> Int {
+    return x.i
+}
+
 //////////////////////////////////////////
 // MARK: Trivial Struct Consuming Tests //
 //////////////////////////////////////////