[ShrinkBorrowScope] Barriers use callee analysis.

Pass a BasicCalleeAnalysis instance to isDeinitBarrier.  This will allow
ShrinkBorrowScope to hoist end_borrows over applies of functions which
are not deinit barriers.

Author: nate-chandler

include/swift/SILOptimizer/Utils/CanonicalizeBorrowScope.h

@@ -37,6 +37,8 @@
 
 namespace swift {
 
+class BasicCalleeAnalysis;
+
 //===----------------------------------------------------------------------===//
 //                       MARK: CanonicalizeBorrowScope
 //===----------------------------------------------------------------------===//
@@ -149,6 +151,7 @@ class CanonicalizeBorrowScope {
 
 bool shrinkBorrowScope(
     BeginBorrowInst const &bbi, InstructionDeleter &deleter,
+    BasicCalleeAnalysis *calleeAnalysis,
     SmallVectorImpl<CopyValueInst *> &modifiedCopyValueInsts);
 
 MoveValueInst *foldDestroysOfCopiedLexicalBorrow(BeginBorrowInst *bbi,

lib/SILOptimizer/Transforms/CopyPropagation.cpp

@@ -43,6 +43,7 @@
 #include "swift/SIL/BasicBlockUtils.h"
 #include "swift/SIL/DebugUtils.h"
 #include "swift/SIL/SILUndef.h"
+#include "swift/SILOptimizer/Analysis/BasicCalleeAnalysis.h"
 #include "swift/SILOptimizer/Analysis/DeadEndBlocksAnalysis.h"
 #include "swift/SILOptimizer/PassManager/Passes.h"
 #include "swift/SILOptimizer/PassManager/Transforms.h"
@@ -440,6 +441,7 @@ void CopyPropagation::run() {
   CanonicalizeOSSALifetime canonicalizer(
       pruneDebug, /*maximizeLifetime=*/!getFunction()->shouldOptimize(),
       accessBlockAnalysis, domTree, deleter);
+  auto *calleeAnalysis = getAnalysis<BasicCalleeAnalysis>();
 
   // NOTE: We assume that the function is in reverse post order so visiting the
   //       blocks and pushing begin_borrows as we see them and then popping them
@@ -453,7 +455,8 @@ void CopyPropagation::run() {
     // at least once and then until each stops making changes.
     while (true) {
       SmallVector<CopyValueInst *, 4> modifiedCopyValueInsts;
-      auto shrunk = shrinkBorrowScope(*bbi, deleter, modifiedCopyValueInsts);
+      auto shrunk = shrinkBorrowScope(*bbi, deleter, calleeAnalysis,
+                                      modifiedCopyValueInsts);
       for (auto *cvi : modifiedCopyValueInsts)
         defWorklist.updateForCopy(cvi);
       changed |= shrunk;

lib/SILOptimizer/Utils/ShrinkBorrowScope.cpp

@@ -62,13 +62,16 @@ struct Context final {
 
   InstructionDeleter &deleter;
 
+  BasicCalleeAnalysis *calleeAnalysis;
+
   Context(BeginBorrowInst const &introducer,
           SmallVectorImpl<CopyValueInst *> &modifiedCopyValueInsts,
-          InstructionDeleter &deleter)
+          InstructionDeleter &deleter, BasicCalleeAnalysis *calleeAnalysis)
       : introducer(introducer), borrowedValue(BorrowedValue(&introducer)),
         borrowee(introducer.getOperand()), defBlock(introducer.getParent()),
         function(*introducer.getFunction()),
-        modifiedCopyValueInsts(modifiedCopyValueInsts), deleter(deleter) {}
+        modifiedCopyValueInsts(modifiedCopyValueInsts), deleter(deleter),
+        calleeAnalysis(calleeAnalysis) {}
   Context(Context const &) = delete;
   Context &operator=(Context const &) = delete;
 };
@@ -245,7 +248,7 @@ Dataflow::classifyInstruction(SILInstruction *instruction) {
                ? Classification::Barrier
                : Classification::Other;
   }
-  if (isDeinitBarrier(instruction, nullptr)) {
+  if (isDeinitBarrier(instruction, context.calleeAnalysis)) {
     return Classification::Barrier;
   }
   return Classification::Other;
@@ -450,7 +453,9 @@ bool run(Context &context) {
 
 bool swift::shrinkBorrowScope(
     BeginBorrowInst const &bbi, InstructionDeleter &deleter,
+    BasicCalleeAnalysis *calleeAnalysis,
     SmallVectorImpl<CopyValueInst *> &modifiedCopyValueInsts) {
-  ShrinkBorrowScope::Context context(bbi, modifiedCopyValueInsts, deleter);
+  ShrinkBorrowScope::Context context(bbi, modifiedCopyValueInsts, deleter,
+                                     calleeAnalysis);
   return ShrinkBorrowScope::run(context);
 }

test/SILOptimizer/shrink_borrow_scope.sil

@@ -1,4 +1,6 @@
-// RUN: %target-sil-opt -copy-propagation -enable-sil-verify-all %s | %FileCheck %s
+// RUN: %target-sil-opt -compute-side-effects -copy-propagation -enable-sil-verify-all %s | %FileCheck %s
+
+// REQUIRES: swift_in_compiler
 
 import Builtin
 import Swift
@@ -50,6 +52,11 @@ sil [ossa] @synchronization_point : $@convention(thin) () -> ()
 sil [ossa] @modify_s : $@yield_once @convention(thin) () -> @yields @inout S
 sil [ossa] @barrier : $@convention(thin) () -> ()
 sil [ossa] @failable : $@convention(thin) () -> @error Error
+// This function is not a synchronization point.
+sil [ossa] @empty : $@convention(thin) () -> () {
+  %retval = tuple ()
+  return %retval : $()
+}
 
 
 // =============================================================================
@@ -1094,6 +1101,27 @@ bb0(%0 : $*ClassWrapper):
   return %23 : $()
 }
 
+// Hoist over applies of non-barrier fns.
+// CHECK-LABEL: sil [ossa] @hoist_over_apply_of_non_barrier_fn : {{.*}} {
+// CHECK:         apply
+// CHECK:         end_borrow
+// CHECK:         apply
+// CHECK-LABEL: } // end sil function 'hoist_over_apply_of_non_barrier_fn'
+sil [ossa] @hoist_over_apply_of_non_barrier_fn : $@convention(thin) () -> () {
+entry:
+  %get_owned_c = function_ref @get_owned_c : $@convention(thin) () -> (@owned C)
+  %c = apply %get_owned_c() : $@convention(thin) () -> (@owned C)
+  %borrow = begin_borrow [lexical] %c : $C
+  %callee_guaranteed = function_ref @callee_guaranteed : $@convention(thin) (@guaranteed C) -> ()
+  apply %callee_guaranteed(%borrow) : $@convention(thin) (@guaranteed C) -> ()
+  %empty = function_ref @empty : $@convention(thin) () -> ()
+  apply %empty() : $@convention(thin) () -> ()
+  end_borrow %borrow : $C
+  destroy_value %c : $C
+  %retval = tuple ()
+  return %retval : $()
+}
+
 // =============================================================================
 // instruction tests                                                          }}
 // =============================================================================