PerformanceInliner: prevent inlining of lazy property getters

Lazy property getters are usually non tivial functions (otherwise the user would not implement it as lazy property).
Inlining such getters would most likely not benefit other optimizations because the top-level switch_enum cannot be constant folded in most cases.
Also, not inlining lazy property getters enables optimizing them in CSE.

Author: eeckstein

lib/SIL/SILFunctionBuilder.cpp

@@ -179,6 +179,15 @@ SILFunction *SILFunctionBuilder::getOrCreateFunction(
       if (varDecl && varDecl->getAttrs().hasAttribute<LazyAttr>() &&
           accessor->getAccessorKind() == AccessorKind::Get) {
         F->setSpecialPurpose(SILFunction::Purpose::LazyPropertyGetter);
+        
+        // Lazy property getters should not get inlined because they are usually
+        // non-tivial functions (otherwise the user would not implement it as
+        // lazy property). Inlining such getters would most likely not benefit
+        // other optimizations because the top-level switch_enum cannot be
+        // constant folded in most cases.
+        // Also, not inlining lazy property getters enables optimizing them in
+        // CSE.
+        F->setInlineStrategy(NoInline);
       }
     }
     addFunctionAttributes(F, decl->getAttrs(), mod, getOrCreateDeclaration,

test/SILGen/lazy_properties.swift

@@ -2,7 +2,7 @@
 
 // <rdar://problem/17405715> lazy property crashes silgen of implicit memberwise initializer
 
-// CHECK-LABEL: sil hidden [lazy_getter] [ossa] @$s15lazy_properties19StructWithLazyFieldV4onceSivg : $@convention(method) (@inout StructWithLazyField) -> Int
+// CHECK-LABEL: sil hidden [lazy_getter] [noinline] [ossa] @$s15lazy_properties19StructWithLazyFieldV4onceSivg : $@convention(method) (@inout StructWithLazyField) -> Int
 
 // CHECK-LABEL: sil hidden [ossa] @$s15lazy_properties19StructWithLazyFieldV4onceSivs : $@convention(method) (Int, @inout StructWithLazyField) -> ()
 
@@ -23,7 +23,7 @@ func test21057425() {
 
 // Anonymous closure parameters in lazy initializer crash SILGen
 
-// CHECK-LABEL: sil hidden [lazy_getter] [ossa] @$s15lazy_properties22HasAnonymousParametersV1xSivg : $@convention(method) (@inout HasAnonymousParameters) -> Int
+// CHECK-LABEL: sil hidden [lazy_getter] [noinline] [ossa] @$s15lazy_properties22HasAnonymousParametersV1xSivg : $@convention(method) (@inout HasAnonymousParameters) -> Int
 
 // CHECK-LABEL: sil private [ossa] @$s15lazy_properties22HasAnonymousParametersV1xSivgS2iXEfU_ : $@convention(thin) (Int) -> Int
 
@@ -39,7 +39,7 @@ class LazyClass {
   lazy var x = 0
 }
 
-// CHECK-LABEL: sil hidden [lazy_getter] [ossa] @$s15lazy_properties9LazyClassC1xSivg : $@convention(method) (@guaranteed LazyClass) -> Int
+// CHECK-LABEL: sil hidden [lazy_getter] [noinline] [ossa] @$s15lazy_properties9LazyClassC1xSivg : $@convention(method) (@guaranteed LazyClass) -> Int
 // CHECK: ref_element_addr %0 : $LazyClass, #LazyClass.$__lazy_storage_$_x
 // CHECK: return
 

test/SILGen/objc_properties.swift

@@ -242,7 +242,7 @@ class HasLazyProperty : NSObject, HasProperty {
   lazy var window = self.instanceMethod()
 }
 
-// CHECK-LABEL: sil hidden [lazy_getter] [ossa] @$s15objc_properties15HasLazyPropertyC6windowSo8NSObjectCSgvg : $@convention(method) (@guaranteed HasLazyProperty) -> @owned Optional<NSObject> {
+// CHECK-LABEL: sil hidden [lazy_getter] [noinline] [ossa] @$s15objc_properties15HasLazyPropertyC6windowSo8NSObjectCSgvg : $@convention(method) (@guaranteed HasLazyProperty) -> @owned Optional<NSObject> {
 // CHECK: class_method %0 : $HasLazyProperty, #HasLazyProperty.instanceMethod!1 : (HasLazyProperty) -> () -> NSObject?
 // CHECK: return
 

test/SILGen/opaque_result_type.swift

@@ -157,7 +157,7 @@ class Sub2 : Base {}
 
 public class D {
    var cond = true
-   // CHECK-LABEL: sil private [lazy_getter] [ossa] @$s18opaque_result_type1DC1c33_C2C55A4BAF30C3244D4A165D48A91142LLQrvg
+   // CHECK-LABEL: sil private [lazy_getter] [noinline] [ossa] @$s18opaque_result_type1DC1c33_C2C55A4BAF30C3244D4A165D48A91142LLQrvg
    // CHECK: bb3([[RET:%[0-9]+]] : @owned $Base):
    // CHECH:  return [[RET]]
    // CHECK: } // end sil function '$s18opaque_result_type1DC1c33_C2C55A4BAF30C3244D4A165D48A91142LLQrvg'

test/SILGen/optional_to_bool.swift

@@ -5,10 +5,10 @@ extension Int: P {}
 
 public class A {}
 public class B: A {
-  // CHECK-LABEL: sil [lazy_getter] [ossa] @$s16optional_to_bool1BC1x{{[_0-9a-zA-Z]*}}vg
+  // CHECK-LABEL: sil [lazy_getter] [noinline] [ossa] @$s16optional_to_bool1BC1x{{[_0-9a-zA-Z]*}}vg
   // CHECK:         switch_enum {{%.*}} : $Optional<Int>
   public lazy var x: Int = 0
-  // CHECK-LABEL: sil [lazy_getter] [ossa] @$s16optional_to_bool1BC1y{{[_0-9a-zA-Z]*}}vg
+  // CHECK-LABEL: sil [lazy_getter] [noinline] [ossa] @$s16optional_to_bool1BC1y{{[_0-9a-zA-Z]*}}vg
   // CHECK:         switch_enum_addr {{%.*}} : $*Optional<P>
   public lazy var y: P = 0
 }