8 files changed, 57 insertions, 0 deletions
diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index 2bd2d5f0a1..fbfee12be9 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -2024,6 +2024,20 @@ void InstructionSimplifierVisitor::SimplifyStringEquals(HInvoke* instruction) {
     ReferenceTypeInfo argument_rti = argument->GetReferenceTypeInfo();
     if (argument_rti.IsValid() && argument_rti.IsStringClass()) {
       optimizations.SetArgumentIsString();
+    } else if (kUseReadBarrier) {
+      DCHECK(instruction->GetResolvedMethod() != nullptr);
+      DCHECK(instruction->GetResolvedMethod()->GetDeclaringClass()->IsStringClass());
+      Runtime* runtime = Runtime::Current();
+      // For AOT, we always assume that the boot image shall contain the String.class and
+      // we do not need a read barrier for boot image classes as they are non-moveable.
+      // For JIT, check if we actually have a boot image; if we do, the String.class
+      // should also be non-moveable.
+      if (runtime->IsAotCompiler() || runtime->GetHeap()->HasBootImageSpace()) {
+        DCHECK(runtime->IsAotCompiler() ||
+               !runtime->GetHeap()->IsMovableObject(
+                   instruction->GetResolvedMethod()->GetDeclaringClass()));
+        optimizations.SetNoReadBarrierForStringClass();
+      }
     }
   }
 }
diff --git a/compiler/optimizing/intrinsics.h b/compiler/optimizing/intrinsics.h
index bdeb261dbe..707ff3408e 100644
--- a/compiler/optimizing/intrinsics.h
+++ b/compiler/optimizing/intrinsics.h
@@ -203,6 +203,7 @@ class StringEqualsOptimizations : public IntrinsicOptimizations {
 
   INTRINSIC_OPTIMIZATION(ArgumentNotNull, 0);
   INTRINSIC_OPTIMIZATION(ArgumentIsString, 1);
+  INTRINSIC_OPTIMIZATION(NoReadBarrierForStringClass, 2);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(StringEqualsOptimizations);
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc
index ef85f9ccc4..ca1b451e6b 100644
--- a/compiler/optimizing/intrinsics_arm64.cc
+++ b/compiler/optimizing/intrinsics_arm64.cc
@@ -1519,6 +1519,13 @@ static const char* GetConstString(HInstruction* candidate, uint32_t* utf16_lengt
 }
 
 void IntrinsicLocationsBuilderARM64::VisitStringEquals(HInvoke* invoke) {
+  if (kEmitCompilerReadBarrier &&
+      !StringEqualsOptimizations(invoke).GetArgumentIsString() &&
+      !StringEqualsOptimizations(invoke).GetNoReadBarrierForStringClass()) {
+    // No support for this odd case (String class is moveable, not in the boot image).
+    return;
+  }
+
   LocationSummary* locations =
       new (allocator_) LocationSummary(invoke, LocationSummary::kNoCall, kIntrinsified);
   locations->SetInAt(0, Location::RequiresRegister());
diff --git a/compiler/optimizing/intrinsics_arm_vixl.cc b/compiler/optimizing/intrinsics_arm_vixl.cc
index e0874d9549..1d8ea092a4 100644
--- a/compiler/optimizing/intrinsics_arm_vixl.cc
+++ b/compiler/optimizing/intrinsics_arm_vixl.cc
@@ -1723,6 +1723,13 @@ static const char* GetConstString(HInstruction* candidate, uint32_t* utf16_lengt
 }
 
 void IntrinsicLocationsBuilderARMVIXL::VisitStringEquals(HInvoke* invoke) {
+  if (kEmitCompilerReadBarrier &&
+      !StringEqualsOptimizations(invoke).GetArgumentIsString() &&
+      !StringEqualsOptimizations(invoke).GetNoReadBarrierForStringClass()) {
+    // No support for this odd case (String class is moveable, not in the boot image).
+    return;
+  }
+
   LocationSummary* locations =
       new (allocator_) LocationSummary(invoke, LocationSummary::kNoCall, kIntrinsified);
   InvokeRuntimeCallingConventionARMVIXL calling_convention;
diff --git a/compiler/optimizing/intrinsics_mips.cc b/compiler/optimizing/intrinsics_mips.cc
index 4a8fbf26ce..140526a018 100644
--- a/compiler/optimizing/intrinsics_mips.cc
+++ b/compiler/optimizing/intrinsics_mips.cc
@@ -2062,6 +2062,13 @@ void IntrinsicCodeGeneratorMIPS::VisitStringCompareTo(HInvoke* invoke) {
 
 // boolean java.lang.String.equals(Object anObject)
 void IntrinsicLocationsBuilderMIPS::VisitStringEquals(HInvoke* invoke) {
+  if (kEmitCompilerReadBarrier &&
+      !StringEqualsOptimizations(invoke).GetArgumentIsString() &&
+      !StringEqualsOptimizations(invoke).GetNoReadBarrierForStringClass()) {
+    // No support for this odd case (String class is moveable, not in the boot image).
+    return;
+  }
+
   LocationSummary* locations =
       new (allocator_) LocationSummary(invoke, LocationSummary::kNoCall, kIntrinsified);
   locations->SetInAt(0, Location::RequiresRegister());
diff --git a/compiler/optimizing/intrinsics_mips64.cc b/compiler/optimizing/intrinsics_mips64.cc
index 512fb68fad..a58ff7c7f2 100644
--- a/compiler/optimizing/intrinsics_mips64.cc
+++ b/compiler/optimizing/intrinsics_mips64.cc
@@ -1637,6 +1637,13 @@ void IntrinsicCodeGeneratorMIPS64::VisitStringCompareTo(HInvoke* invoke) {
 
 // boolean java.lang.String.equals(Object anObject)
 void IntrinsicLocationsBuilderMIPS64::VisitStringEquals(HInvoke* invoke) {
+  if (kEmitCompilerReadBarrier &&
+      !StringEqualsOptimizations(invoke).GetArgumentIsString() &&
+      !StringEqualsOptimizations(invoke).GetNoReadBarrierForStringClass()) {
+    // No support for this odd case (String class is moveable, not in the boot image).
+    return;
+  }
+
   LocationSummary* locations =
       new (allocator_) LocationSummary(invoke, LocationSummary::kNoCall, kIntrinsified);
   locations->SetInAt(0, Location::RequiresRegister());
diff --git a/compiler/optimizing/intrinsics_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index 8a0b6aeb0e..baa410b884 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -1345,6 +1345,13 @@ void IntrinsicCodeGeneratorX86::VisitStringCompareTo(HInvoke* invoke) {
 }
 
 void IntrinsicLocationsBuilderX86::VisitStringEquals(HInvoke* invoke) {
+  if (kEmitCompilerReadBarrier &&
+      !StringEqualsOptimizations(invoke).GetArgumentIsString() &&
+      !StringEqualsOptimizations(invoke).GetNoReadBarrierForStringClass()) {
+    // No support for this odd case (String class is moveable, not in the boot image).
+    return;
+  }
+
   LocationSummary* locations =
       new (allocator_) LocationSummary(invoke, LocationSummary::kNoCall, kIntrinsified);
   locations->SetInAt(0, Location::RequiresRegister());
diff --git a/compiler/optimizing/intrinsics_x86_64.cc b/compiler/optimizing/intrinsics_x86_64.cc
index 92ffda427b..6dd8b8e1f5 100644
--- a/compiler/optimizing/intrinsics_x86_64.cc
+++ b/compiler/optimizing/intrinsics_x86_64.cc
@@ -1520,6 +1520,13 @@ void IntrinsicCodeGeneratorX86_64::VisitStringCompareTo(HInvoke* invoke) {
 }
 
 void IntrinsicLocationsBuilderX86_64::VisitStringEquals(HInvoke* invoke) {
+  if (kEmitCompilerReadBarrier &&
+      !StringEqualsOptimizations(invoke).GetArgumentIsString() &&
+      !StringEqualsOptimizations(invoke).GetNoReadBarrierForStringClass()) {
+    // No support for this odd case (String class is moveable, not in the boot image).
+    return;
+  }
+
   LocationSummary* locations =
       new (allocator_) LocationSummary(invoke, LocationSummary::kNoCall, kIntrinsified);
   locations->SetInAt(0, Location::RequiresRegister());