[loong64][compiler] Add bottleneck for static roots check in MacroAssembler

zjiaz · V8 LUCI CQ · commit cae7aad5ed89 · 2025-10-15T03:29:15.000-07:00
Port commit 6a8fa0d Besides, port a missed commit 0523061 - [masm] Add quick check for RO values to write barrier Change-Id: I8c7ac524290203df0e95d90188a89aff8931de8f Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/6994010 Auto-Submit: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn> Reviewed-by: Michael Lippautz <mlippautz@chromium.org> Commit-Queue: Zhao Jiazhong <zhaojiazhong-hf@loongson.cn> Cr-Commit-Position: refs/heads/main@{#103126}
diff --git a/src/codegen/loong64/macro-assembler-loong64.cc b/src/codegen/loong64/macro-assembler-loong64.cc
@@ -194,18 +194,34 @@ void MacroAssembler::PreCheckSkippedWriteBarrier(Register object,
   bind(&not_ok);
 }
 
+void MacroAssembler::MaybeJumpIfReadOnlyOrSmallSmi(Register value,
+                                                   Label* dest) {
+#if V8_STATIC_ROOTS_BOOL
+  // Quick check for Read-only and small Smi values.
+  static_assert(StaticReadOnlyRoot::kLastAllocatedRoot < kRegularPageSize);
+  JumpIfUnsignedLessThan(value, kRegularPageSize, dest);
+#endif  // V8_STATIC_ROOTS_BOOL
+}
+
 // Clobbers object, dst, value, and ra, if (ra_status == kRAHasBeenSaved)
 // The register 'object' contains a heap object pointer.  The heap object
 // tag is shifted away.
 void MacroAssembler::RecordWriteField(Register object, int offset,
                                       Register value, RAStatus ra_status,
                                       SaveFPRegsMode save_fp,
-                                      SmiCheck smi_check, SlotDescriptor slot) {
+                                      SmiCheck smi_check,
+                                      ReadOnlyCheck ro_check,
+                                      SlotDescriptor slot) {
   ASM_CODE_COMMENT(this);
+  DCHECK(!AreAliased(object, value));
   // First, check if a write barrier is even needed. The tests below
-  // catch stores of Smis.
+  // catch stores of Smis and read-only objects.
   Label done;
 
+  if (ro_check == ReadOnlyCheck::kInline) {
+    MaybeJumpIfReadOnlyOrSmallSmi(value, &done);
+  }
+
   // Skip barrier if writing a smi.
   if (smi_check == SmiCheck::kInline) {
     JumpIfSmi(value, &done);
@@ -228,7 +244,7 @@ void MacroAssembler::RecordWriteField(Register object, int offset,
   }
 
   RecordWrite(object, Operand(offset - kHeapObjectTag), value, ra_status,
-              save_fp, SmiCheck::kOmit, slot);
+              save_fp, SmiCheck::kOmit, ReadOnlyCheck::kOmit, slot);
 
   bind(&done);
 }
@@ -703,7 +719,7 @@ void MacroAssembler::MoveObjectAndSlot(Register dst_object, Register dst_slot,
 void MacroAssembler::RecordWrite(Register object, Operand offset,
                                  Register value, RAStatus ra_status,
                                  SaveFPRegsMode fp_mode, SmiCheck smi_check,
-                                 SlotDescriptor slot) {
+                                 ReadOnlyCheck ro_check, SlotDescriptor slot) {
   DCHECK(!AreAliased(object, value));
 
   if (v8_flags.slow_debug_code) {
@@ -726,9 +742,14 @@ void MacroAssembler::RecordWrite(Register object, Operand offset,
   }
 
   // First, check if a write barrier is even needed. The tests below
-  // catch stores of smis and stores into the young generation.
+  // catch stores of smis and read-only objects, as well as stores into the
+  // young generation.
   Label done;
 
+  if (ro_check == ReadOnlyCheck::kInline) {
+    MaybeJumpIfReadOnlyOrSmallSmi(value, &done);
+  }
+
   if (smi_check == SmiCheck::kInline) {
     DCHECK_EQ(0, kSmiTag);
     JumpIfSmi(value, &done);
@@ -5312,7 +5333,7 @@ void MacroAssembler::ReplaceClosureCodeWithOptimizedCode(
                         FieldMemOperand(closure, JSFunction::kCodeOffset));
   RecordWriteField(closure, JSFunction::kCodeOffset, optimized_code,
                    kRAHasNotBeenSaved, SaveFPRegsMode::kIgnore, SmiCheck::kOmit,
-                   SlotDescriptor::ForCodePointerSlot());
+                   ReadOnlyCheck::kOmit, SlotDescriptor::ForCodePointerSlot());
 }
 
 // Read off the flags in the feedback vector and check if there
diff --git a/src/codegen/loong64/macro-assembler-loong64.h b/src/codegen/loong64/macro-assembler-loong64.h
@@ -817,18 +817,20 @@ class V8_EXPORT_PRIVATE MacroAssembler : public MacroAssemblerBase {
   // Jump the register contains a smi.
   void JumpIfSmi(Register value, Label* smi_label);
 
-  void JumpIfEqual(Register a, int32_t b, Label* dest) {
-    UseScratchRegisterScope temps(this);
-    Register scratch = temps.Acquire();
-    li(scratch, Operand(b));
-    Branch(dest, eq, a, Operand(scratch));
+  inline void JumpIf(Condition cond, Register x, int32_t y, Label* dest) {
+    Branch(dest, cond, x, Operand(y));
   }
 
-  void JumpIfLessThan(Register a, int32_t b, Label* dest) {
-    UseScratchRegisterScope temps(this);
-    Register scratch = temps.Acquire();
-    li(scratch, Operand(b));
-    Branch(dest, lt, a, Operand(scratch));
+  inline void JumpIfEqual(Register x, int32_t y, Label* dest) {
+    Branch(dest, eq, x, Operand(y));
+  }
+
+  inline void JumpIfLessThan(Register x, int32_t y, Label* dest) {
+    Branch(dest, lt, x, Operand(y));
+  }
+
+  inline void JumpIfUnsignedLessThan(Register x, int32_t y, Label* dest) {
+    Branch(dest, lo, x, Operand(y));
   }
 
   // Push a standard frame, consisting of ra, fp, context and JS function.
@@ -1058,6 +1060,10 @@ class V8_EXPORT_PRIVATE MacroAssembler : public MacroAssemblerBase {
   // ---------------------------------------------------------------------------
   // GC Support
 
+  // Performs a fast check for whether `value` is a read-only object or a small
+  // Smi. Only enabled in some configurations.
+  void MaybeJumpIfReadOnlyOrSmallSmi(Register value, Label* dest);
+
   // Notify the garbage collector that we wrote a pointer into an object.
   // |object| is the object being stored into, |value| is the object being
   // stored.
@@ -1066,13 +1072,15 @@ class V8_EXPORT_PRIVATE MacroAssembler : public MacroAssemblerBase {
   void RecordWriteField(
       Register object, int offset, Register value, RAStatus ra_status,
       SaveFPRegsMode save_fp, SmiCheck smi_check = SmiCheck::kInline,
+      ReadOnlyCheck ro_check = ReadOnlyCheck::kInline,
       SlotDescriptor slot = SlotDescriptor::ForDirectPointerSlot());
 
   // For a given |object| notify the garbage collector that the slot at |offset|
   // has been written.  |value| is the object being stored.
   void RecordWrite(
       Register object, Operand offset, Register value, RAStatus ra_status,
       SaveFPRegsMode save_fp, SmiCheck smi_check = SmiCheck::kInline,
+      ReadOnlyCheck ro_check = ReadOnlyCheck::kInline,
       SlotDescriptor slot = SlotDescriptor::ForDirectPointerSlot());
 
   // ---------------------------------------------------------------------------
diff --git a/src/compiler/backend/loong64/code-generator-loong64.cc b/src/compiler/backend/loong64/code-generator-loong64.cc
@@ -1068,6 +1068,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       Register scratch = i.TempRegister(0);
       auto ool = zone()->New<OutOfLineVerifySkippedWriteBarrier>(
           this, object, value, scratch);
+      __ MaybeJumpIfReadOnlyOrSmallSmi(value, ool->exit());
       __ JumpIfNotSmi(value, ool->entry());
       __ bind(ool->exit());
 
@@ -1128,6 +1129,7 @@ CodeGenerator::CodeGenResult CodeGenerator::AssembleArchInstruction(
       Register scratch = i.TempRegister(1);
       auto ool = zone()->New<OutOfLineVerifySkippedWriteBarrier>(
           this, object, value, scratch);
+      __ MaybeJumpIfReadOnlyOrSmallSmi(value, ool->exit());
       __ JumpIfNotSmi(value, ool->entry());
       __ bind(ool->exit());
 
