[closure-lifetime-fixup] Make sure that all copy_value we insert have a data dependence on the cvt_escape_to_no_escape.

Otherwise, the ownership model doesn't understand the need for the copies and
just removes them.

Author: gottesmm

lib/SILOptimizer/Mandatory/ClosureLifetimeFixup.cpp

@@ -122,8 +122,6 @@ static void extendLifetimeToEndOfFunction(SILFunction &fn,
   auto optionalEscapingClosureTy = SILType::getOptionalType(escapingClosureTy);
   auto loc = RegularLocation::getAutoGeneratedLocation();
 
-  cvt->setLifetimeGuaranteed();
-
   // If our Cvt is in the initial block, we do not need to use the SSA updater
   // since we know Cvt can not be in a loop and must dominate all exits
   // (*). Just insert a copy of the escaping closure at the Cvt and destroys at
@@ -133,6 +131,8 @@ static void extendLifetimeToEndOfFunction(SILFunction &fn,
   if (cvt->getParent() == cvt->getFunction()->getEntryBlock()) {
     auto *innerCVI =
         SILBuilderWithScope(cvt).createCopyValue(loc, escapingClosure);
+    cvt->setLifetimeGuaranteed();
+    cvt->setOperand(innerCVI);
     SmallVector<SILBasicBlock *, 4> exitingBlocks;
     fn.findExitingBlocks(exitingBlocks);
 
@@ -167,8 +167,11 @@ static void extendLifetimeToEndOfFunction(SILFunction &fn,
   // block without extra work. So the fact that Cvt is not in the entry block
   // means that we don't have to worry about overwriting the .none value.
   auto *cvi = [&]() -> CopyValueInst * {
-    SILBuilderWithScope b(cvt);
-    auto *innerCVI = b.createCopyValue(loc, escapingClosure);
+    auto *innerCVI =
+        SILBuilderWithScope(cvt).createCopyValue(loc, escapingClosure);
+    cvt->setLifetimeGuaranteed();
+    cvt->setOperand(innerCVI);
+    SILBuilderWithScope b(std::next(cvt->getIterator()));
     updater.AddAvailableValue(
         cvt->getParent(),
         b.createOptionalSome(loc, innerCVI, optionalEscapingClosureTy));
@@ -407,10 +410,10 @@ static bool tryExtendLifetimeToLastUse(
     // Insert a copy at the convert_escape_to_noescape [not_guaranteed] and
     // change the instruction to the guaranteed form.
     auto escapingClosure = cvt->getOperand();
-    cvt->setLifetimeGuaranteed();
-
     auto *closureCopy =
         SILBuilderWithScope(cvt).createCopyValue(loc, escapingClosure);
+    cvt->setLifetimeGuaranteed();
+    cvt->setOperand(closureCopy);
 
     // Insert a destroy after the apply.
     if (auto *apply = dyn_cast<ApplyInst>(singleApplyUser.getInstruction())) {
@@ -492,14 +495,17 @@ static bool trySwitchEnumPeephole(ConvertEscapeToNoEscapeInst *cvt) {
   if (!onlyDestroy)
     return false;
 
-  cvt->setLifetimeGuaranteed();
-
   // Extend the lifetime.
-  SILBuilderWithScope b(switchEnum1);
   auto loc = RegularLocation::getAutoGeneratedLocation();
-  auto copy = b.createCopyValue(loc, switchEnum1->getOperand());
-  b.setInsertionPoint(onlyDestroy);
-  b.createDestroyValue(loc, copy);
+  auto *copy = SILBuilderWithScope(switchEnum1)
+                   .createCopyValue(loc, switchEnum1->getOperand());
+
+  cvt->setLifetimeGuaranteed();
+  auto *mdi = SILBuilderWithScope(cvt).createMarkDependence(
+      loc, cvt->getOperand(), copy);
+  cvt->setOperand(mdi);
+
+  SILBuilderWithScope(onlyDestroy).createDestroyValue(loc, copy);
   return true;
 }
 

test/SILOptimizer/definite-init-convert-to-escape.swift

@@ -45,8 +45,9 @@ public func returnOptionalEscape() -> (() ->())?
 // CHECK:  retain_value [[V1]]
 // CHECK:  switch_enum [[V1]] : $Optional<{{.*}}>, case #Optional.some!enumelt.1: [[SOME_BB:bb[0-9]+]], case #Optional.none!enumelt: [[NONE_BB:bb[0-9]+]]
 //
-// CHECK: [[SOME_BB]]([[V2:%.*]]: $@callee_guaranteed () -> ()):
-// CHECK:  [[CVT:%.*]] = convert_escape_to_noescape [[V2]]
+// CHECK: [[SOME_BB]]([[V2:%.*]] : $@callee_guaranteed () -> ()):
+// CHECK:  [[CVT_MARK_DEP:%.*]] = mark_dependence [[V2]] : $@callee_guaranteed () -> () on [[V1]]
+// CHECK:  [[CVT:%.*]] = convert_escape_to_noescape [[CVT_MARK_DEP]]
 // CHECK:  [[SOME:%.*]] = enum $Optional<{{.*}}>, #Optional.some!enumelt.1, [[CVT]]
 // CHECK:  strong_release [[V2]]
 // CHECK:  br [[NEXT_BB:bb[0-9]+]]([[SOME]] :
@@ -89,8 +90,8 @@ public func returnOptionalEscape() -> (() ->())?
 //
 // NOPEEPHOLE: [[SOME_BB]]([[V2:%.*]]: $@callee_guaranteed () -> ()):
 // NOPEEPHOLE-NEXT:  release_value [[NONE_2]]
-// NOPEEPHOLE-NEXT:  [[SOME:%.*]] = enum $Optional<{{.*}}>, #Optional.some!enumelt.1, [[V2]]
 // NOPEEPHOLE-NEXT:  [[CVT:%.*]] = convert_escape_to_noescape [[V2]]
+// NOPEEPHOLE-NEXT:  [[SOME:%.*]] = enum $Optional<{{.*}}>, #Optional.some!enumelt.1, [[V2]]
 // NOPEEPHOLE-NEXT:  [[NOESCAPE_SOME:%.*]] = enum $Optional<{{.*}}>, #Optional.some!enumelt.1, [[CVT]]
 // NOPEEPHOLE-NEXT:  br bb2([[NOESCAPE_SOME]] : $Optional<{{.*}}>, [[SOME]] :
 //