commit d1aef75e044412ccb9ee6613591f02b130c9962e
author Christoffer Quist Adamsen <christofferqa@google.com> Thu Apr 20 08:07:36 2023 +0200
committer Christoffer Quist Adamsen <christofferqa@google.com> Thu Apr 20 08:07:36 2023 +0200
tree 4b18acd856dc7fd94a770995d3b33466eac86087
parent 09a83b0eff14dd3c530a52a83a2035dd250cc94c

Avoid redundant synthesis in var handle desugaring

Bug: b/278817819
Change-Id: I50cf5c2bb239de0e1a4a176b96bcab64c727e7be

src/main/java/com/android/tools/r8/ir/desugar/varhandle/VarHandleDesugaring.java

diff --git a/src/main/java/com/android/tools/r8/ir/desugar/varhandle/VarHandleDesugaring.java b/src/main/java/com/android/tools/r8/ir/desugar/varhandle/VarHandleDesugaring.java
index 80f114f4..063286c 100644
--- a/src/main/java/com/android/tools/r8/ir/desugar/varhandle/VarHandleDesugaring.java
+++ b/src/main/java/com/android/tools/r8/ir/desugar/varhandle/VarHandleDesugaring.java
@@ -35,6 +35,7 @@
 import com.android.tools.r8.ir.desugar.DesugarDescription;
 import com.android.tools.r8.ir.desugar.FreshLocalProvider;
 import com.android.tools.r8.ir.desugar.LocalStackAllocator;
+import com.android.tools.r8.utils.BitUtils;
 import com.google.common.collect.ImmutableList;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -47,6 +48,9 @@
 
 public class VarHandleDesugaring implements CfInstructionDesugaring, CfClassSynthesizerDesugaring {
 
+  private static final int SYNTHESIZED_METHOD_HANDLES_LOOKUP_CLASS = 1;
+  private static final int SYNTHESIZED_VAR_HANDLE_CLASS_FLAG = 2;
+
   private final AppView<?> appView;
   private final DexItemFactory factory;
 
@@ -70,26 +74,33 @@
       return;
     }
     CfCode cfCode = programMethod.getDefinition().getCode().asCfCode();
+    int synthesizedClasses = 0;
     for (CfInstruction instruction : cfCode.getInstructions()) {
-      scanInstruction(instruction, eventConsumer, programMethod);
+      synthesizedClasses =
+          scanInstruction(instruction, eventConsumer, programMethod, synthesizedClasses);
     }
   }
 
-  private void scanInstruction(
+  private int scanInstruction(
       CfInstruction instruction,
       CfInstructionDesugaringEventConsumer eventConsumer,
-      ProgramMethod context) {
+      ProgramMethod context,
+      int synthesizedClasses) {
     assert !instruction.isInitClass();
     if (instruction.isInvoke()) {
       CfInvoke cfInvoke = instruction.asInvoke();
-      if (refersToVarHandle(cfInvoke.getMethod(), factory)) {
+      if (BitUtils.isBitInMaskUnset(synthesizedClasses, SYNTHESIZED_VAR_HANDLE_CLASS_FLAG)
+          && refersToVarHandle(cfInvoke.getMethod(), factory)) {
         ensureVarHandleClass(eventConsumer, context);
+        synthesizedClasses |= SYNTHESIZED_VAR_HANDLE_CLASS_FLAG;
       }
-      if (refersToMethodHandlesLookup(cfInvoke.getMethod(), factory)) {
+      if (BitUtils.isBitInMaskUnset(synthesizedClasses, SYNTHESIZED_METHOD_HANDLES_LOOKUP_CLASS)
+          && refersToMethodHandlesLookup(cfInvoke.getMethod(), factory)) {
         ensureMethodHandlesLookupClass(eventConsumer, context);
+        synthesizedClasses |= SYNTHESIZED_METHOD_HANDLES_LOOKUP_CLASS;
       }
-      return;
     }
+    return synthesizedClasses;
   }
 
   private static boolean refersToVarHandle(DexType type, DexItemFactory factory) {
@@ -175,6 +186,7 @@
   private void ensureMethodHandlesLookupClass(
       VarHandleDesugaringEventConsumer eventConsumer,
       Collection<? extends ProgramDefinition> contexts) {
+    assert contexts.stream().allMatch(context -> context.getContextType() != factory.lookupType);
     DexProgramClass clazz =
         appView
             .getSyntheticItems()
@@ -201,6 +213,7 @@
   private void ensureVarHandleClass(
       VarHandleDesugaringEventConsumer eventConsumer,
       Collection<? extends ProgramDefinition> contexts) {
+    assert contexts.stream().allMatch(context -> context.getContextType() != factory.varHandleType);
     DexProgramClass clazz =
         appView
             .getSyntheticItems()
@@ -221,7 +234,9 @@
 
   private void ensureVarHandleClass(
       VarHandleDesugaringEventConsumer eventConsumer, ProgramDefinition context) {
-    ensureVarHandleClass(eventConsumer, ImmutableList.of(context));
+    if (context.getContextType() != factory.varHandleType) {
+      ensureVarHandleClass(eventConsumer, ImmutableList.of(context));
+    }
   }
 
   @Override

src/main/java/com/android/tools/r8/utils/BitUtils.java

diff --git a/src/main/java/com/android/tools/r8/utils/BitUtils.java b/src/main/java/com/android/tools/r8/utils/BitUtils.java
index f951031..732d62a 100644
--- a/src/main/java/com/android/tools/r8/utils/BitUtils.java
+++ b/src/main/java/com/android/tools/r8/utils/BitUtils.java
@@ -7,13 +7,17 @@
 public class BitUtils {
 
   public static boolean isBitSet(int value, int which) {
-    return (value & (1 << (which - 1))) != 0;
+    return isBitInMaskSet(value, 1 << (which - 1));
   }
 
   public static boolean isBitInMaskSet(int value, int mask) {
     return (value & mask) != 0;
   }
 
+  public static boolean isBitInMaskUnset(int value, int mask) {
+    return !isBitInMaskSet(value, mask);
+  }
+
   public static boolean isAligned(int alignment, int value) {
     assert (alignment & (alignment - 1)) == 0; // Check alignment is power of 2.
     return (value & (alignment - 1)) == 0;