Changeset 259849 in webkit

Timestamp:

Apr 9, 2020, 11:48:09 PM (6 years ago)

Author:

ysuzuki@apple.com

Message:

[JSC] Use UnconditionalWriteBarrier in Baseline effectively to reduce code size
​https://bugs.webkit.org/show_bug.cgi?id=209395

Reviewed by Tadeu Zagallo.

In put/delete we always need to emit write-barrier if the base is a cell since IC can write things (writing new StructureID etc.).
We should use emitWriteBarrier with UnconditionalWriteBarrier to remove unnecessary branch.

• jit/JITPropertyAccess.cpp:

(JSC::JIT::emitPutByValWithCachedId):
(JSC::JIT::emit_op_del_by_id):
(JSC::JIT::emit_op_del_by_val):
(JSC::JIT::emit_op_put_by_id):

• jit/JITPropertyAccess32_64.cpp:

(JSC::JIT::emitPutByValWithCachedId):
(JSC::JIT::emit_op_put_by_id):

Location:

trunk/Source/JavaScriptCore

Files:

• ChangeLog (modified) (1 diff)
• jit/JITPropertyAccess.cpp (modified) (4 diffs)
• jit/JITPropertyAccess32_64.cpp (modified) (2 diffs)

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2020-04-09  Yusuke Suzuki  <ysuzuki@apple.com>
+
+        [JSC] Use UnconditionalWriteBarrier in Baseline effectively to reduce code size
+        https://bugs.webkit.org/show_bug.cgi?id=209395
+
+        Reviewed by Tadeu Zagallo.
+
+        In put/delete we always need to emit write-barrier if the base is a cell since IC can write things (writing new StructureID etc.).
+        We should use emitWriteBarrier with UnconditionalWriteBarrier to remove unnecessary branch.
+
+        * jit/JITPropertyAccess.cpp:
+        (JSC::JIT::emitPutByValWithCachedId):
+        (JSC::JIT::emit_op_del_by_id):
+        (JSC::JIT::emit_op_del_by_val):
+        (JSC::JIT::emit_op_put_by_id):
+        * jit/JITPropertyAccess32_64.cpp:
+        (JSC::JIT::emitPutByValWithCachedId):
+        (JSC::JIT::emit_op_put_by_id):
+
 2020-04-09  Mark Lam  <mark.lam@apple.com>
 

trunk/Source/JavaScriptCore/jit/JITPropertyAccess.cpp

@@ -291 +291 @@
     gen.generateFastPath(*this);
     // IC can write new Structure without write-barrier if a base is cell.
-    // FIXME: Use UnconditionalWriteBarrier in Baseline effectively to reduce code size.
-    // https://bugs.webkit.org/show_bug.cgi?id=209395
-    emitWriteBarrier(base, ShouldFilterBase);
+    // We emit write-barrier unconditionally since we know baseVRege is a cell.
+    emitWriteBarrier(base, UnconditionalWriteBarrier);
     doneCases.append(jump());
 
@@ -410 +409 @@
 
     // IC can write new Structure without write-barrier if a base is cell.
+    // We emit write-barrier unconditionally since we know baseVRege is a cell.
     // We should emit write-barrier at the end of sequence since write-barrier clobbers registers.
-    // FIXME: Use UnconditionalWriteBarrier in Baseline effectively to reduce code size.
-    // https://bugs.webkit.org/show_bug.cgi?id=209395
-    emitWriteBarrier(base, ShouldFilterBase);
+    emitWriteBarrier(base, UnconditionalWriteBarrier);
 }
 
@@ -460 +458 @@
     // We should emit write-barrier at the end of sequence since write-barrier clobbers registers.
     // IC can write new Structure without write-barrier if a base is cell.
-    // FIXME: Use UnconditionalWriteBarrier in Baseline effectively to reduce code size.
-    // https://bugs.webkit.org/show_bug.cgi?id=209395
-    emitWriteBarrier(base, ShouldFilterBase);
+    // We emit write-barrier unconditionally since we know baseVRege is a cell.
+    emitWriteBarrier(base, UnconditionalWriteBarrier);
 }
 
@@ -679 +676 @@
     
     // IC can write new Structure without write-barrier if a base is cell.
-    // FIXME: Use UnconditionalWriteBarrier in Baseline effectively to reduce code size.
-    // https://bugs.webkit.org/show_bug.cgi?id=209395
-    emitWriteBarrier(baseVReg, ShouldFilterBase);
+    // We emit write-barrier unconditionally since we know baseVRege is a cell.
+    emitWriteBarrier(baseVReg, UnconditionalWriteBarrier);
 }
 

trunk/Source/JavaScriptCore/jit/JITPropertyAccess32_64.cpp

@@ -370 +370 @@
     //
     // IC can write new Structure without write-barrier if a base is cell.
+    // We emit write-barrier unconditionally since we know baseVRege is a cell.
     // We are emitting write-barrier before writing here but this is OK since 32bit JSC does not have concurrent GC.
-    // FIXME: Use UnconditionalWriteBarrier in Baseline effectively to reduce code size.
-    // https://bugs.webkit.org/show_bug.cgi?id=209395
-    emitWriteBarrier(base, ShouldFilterBase);
+    emitWriteBarrier(base, UnconditionalWriteBarrier);
     emitLoadPayload(base, regT0);
     emitLoad(value, regT3, regT2);
@@ -624 +623 @@
     
     // IC can write new Structure without write-barrier if a base is cell.
-    // FIXME: Use UnconditionalWriteBarrier in Baseline effectively to reduce code size.
-    // https://bugs.webkit.org/show_bug.cgi?id=209395
-    emitWriteBarrier(base, ShouldFilterBase);
+    // We emit write-barrier unconditionally since we know baseVRege is a cell.
+    emitWriteBarrier(base, UnconditionalWriteBarrier);
 }