Inliner: Add @_semantics("inline_late")

lib/SILOptimizer/Utils/PerformanceInlinerUtils.cpp

@@ -11,6 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "swift/SILOptimizer/Utils/PerformanceInlinerUtils.h"
+#include "swift/Strings.h"
 
 //===----------------------------------------------------------------------===//
 //                               ConstantTracker
@@ -630,20 +631,32 @@ SILFunction *swift::getEligibleFunction(FullApplySite AI,
   if (!Callee) {
     return nullptr;
   }
+  auto ModuleName = Callee->getModule().getSwiftModule()->getName().str();
+  bool IsInStdlib = (ModuleName == STDLIB_NAME || ModuleName == SWIFT_ONONE_SUPPORT);
 
   // Don't inline functions that are marked with the @_semantics or @effects
   // attribute if the inliner is asked not to inline them.
   if (Callee->hasSemanticsAttrs() || Callee->hasEffectsKind()) {
     if (WhatToInline == InlineSelection::NoSemanticsAndGlobalInit) {
       if (shouldSkipApplyDuringEarlyInlining(AI))
         return nullptr;
+      if (Callee->hasSemanticsAttr("inline_late"))
+        return nullptr;
     }
     // The "availability" semantics attribute is treated like global-init.
     if (Callee->hasSemanticsAttrs() &&
         WhatToInline != InlineSelection::Everything &&
-        Callee->hasSemanticsAttrThatStartsWith("availability")) {
+        (Callee->hasSemanticsAttrThatStartsWith("availability") ||
+         (Callee->hasSemanticsAttrThatStartsWith("inline_late")))) {
       return nullptr;
     }
+    if (Callee->hasSemanticsAttrs() &&
+        WhatToInline == InlineSelection::Everything) {
+      if (Callee->hasSemanticsAttrThatStartsWith("inline_late") && IsInStdlib) {
+        return nullptr;
+      }
+    }
+
   } else if (Callee->isGlobalInit()) {
     if (WhatToInline != InlineSelection::Everything) {
       return nullptr;

test/SILOptimizer/inline_late.sil

@@ -0,0 +1,37 @@
+// RUN: %target-sil-opt -assume-parsing-unqualified-ownership-sil -enable-sil-verify-all %s -early-inline -sil-inline-threshold=50 | %FileCheck %s
+// RUN: %target-sil-opt -assume-parsing-unqualified-ownership-sil -enable-sil-verify-all %s -late-inline -sil-inline-threshold=50 | %FileCheck %s --check-prefix=LATE
+// RUN: %target-sil-opt -assume-parsing-unqualified-ownership-sil -enable-sil-verify-all %s -late-inline -sil-inline-threshold=50 -module-name Swift | %FileCheck %s --check-prefix=STDLIBLATE
+
+sil_stage canonical
+
+import Builtin
+
+sil [_semantics "inline_late"] @inline_late_func : $@convention(thin) () -> Builtin.Int32 {
+bb0:
+  %0 = integer_literal $Builtin.Int32, 3
+  return %0 : $Builtin.Int32
+}
+
+//CHECK-LABEL: caller_func5
+//CHECK: function_ref
+//CHECK: apply
+//CHECK-NEXT: ret
+
+//STDLIBLATE-LABEL: caller_func5
+//STDLIBLATE: function_ref
+//STDLIBLATE: apply
+//STDLIBLATE-NEXT: ret
+
+
+//LATE-LABEL: caller_func5
+//LATE: integer_literal
+//LATE-NOT: function_ref
+//LATE-NOT: apply
+//LATE-NEXT: ret
+
+sil @caller_func5 : $@convention(thin) () -> Builtin.Int32 {
+bb0:
+  %0 = function_ref @inline_late_func : $@convention(thin) () -> Builtin.Int32
+  %1 = apply %0() : $@convention(thin) () -> Builtin.Int32
+  return %1 : $Builtin.Int32
+}