Attachment 341730 Details for Bug 186182 – Patch

[patch] Patch

bug-186182-20180601130307.patch (text/plain), 2.92 KB, created by Yusuke Suzuki on 2018-05-31 21:03:08 PDT

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Creator: Yusuke Suzuki

Created: 2018-05-31 21:03:08 PDT

Size: 2.92 KB

patch

obsolete

>Subversion Revision: 232383
>diff --git a/Source/JavaScriptCore/ChangeLog b/Source/JavaScriptCore/ChangeLog
>index c034df3646cfb9b74b41d0855784e64958330a41..ada1d20ac15d86d138a384670a80f3bd60d9df3f 100644
>--- a/Source/JavaScriptCore/ChangeLog
>+++ b/Source/JavaScriptCore/ChangeLog
>@@ -1,3 +1,24 @@
>+2018-05-31  Yusuke Suzuki  <utatane.tea@gmail.com>
>+
>+        [Baseline] Store constant directly in emit_op_mov
>+        https://bugs.webkit.org/show_bug.cgi?id=186182
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        In the old code, we first move a constant to a register and store it to the specified address.
>+        But in 64bit JSC, we can directly store a constant to the specified address. This reduces the
>+        generated code size. Since the old code was emitting a constant in a code anyway, this change
>+        never increases the size of the generated code.
>+
>+        * jit/JITInlines.h:
>+        (JSC::JIT::emitGetVirtualRegister):
>+        We remove this obsolete comment. Our OSR relies on the fact that values are stored and loaded
>+        from the stack. If we transfer values in registers without loading values from the stack, it
>+        breaks this assumption.
>+
>+        * jit/JITOpcodes.cpp:
>+        (JSC::JIT::emit_op_mov):
>+
> 2018-05-31  Saam Barati  <sbarati@apple.com>
> 
>         JSImmutableButterfly should align its variable storage
>diff --git a/Source/JavaScriptCore/jit/JITInlines.h b/Source/JavaScriptCore/jit/JITInlines.h
>index 30b0ddde2d70ba627d6089656187ab9c647aaae3..723b73ed35d06c5699a221ec7ab4d558402b33ff 100644
>--- a/Source/JavaScriptCore/jit/JITInlines.h
>+++ b/Source/JavaScriptCore/jit/JITInlines.h
>@@ -572,7 +572,6 @@ ALWAYS_INLINE void JIT::emitGetVirtualRegister(int src, RegisterID dst)
> {
>     ASSERT(m_bytecodeOffset != std::numeric_limits<unsigned>::max()); // This method should only be called during hot/cold path generation, so that m_bytecodeOffset is set.
> 
>-    // TODO: we want to reuse values that are already in registers if we can - add a register allocator!
>     if (m_codeBlock->isConstantRegisterIndex(src)) {
>         JSValue value = m_codeBlock->getConstant(src);
>         if (!value.isNumber())
>diff --git a/Source/JavaScriptCore/jit/JITOpcodes.cpp b/Source/JavaScriptCore/jit/JITOpcodes.cpp
>index 38621d886e70c4158ecd7a8eaa9f6dc1105cb829..a5761bff7d6582175703f20b5685b25d039bc7a5 100644
>--- a/Source/JavaScriptCore/jit/JITOpcodes.cpp
>+++ b/Source/JavaScriptCore/jit/JITOpcodes.cpp
>@@ -57,8 +57,14 @@ void JIT::emit_op_mov(Instruction* currentInstruction)
>     int dst = currentInstruction[1].u.operand;
>     int src = currentInstruction[2].u.operand;
> 
>-    emitGetVirtualRegister(src, regT0);
>-    emitPutVirtualRegister(dst);
>+    if (m_codeBlock->isConstantRegisterIndex(src)) {
>+        JSValue value = m_codeBlock->getConstant(src);
>+        store64(TrustedImm64(JSValue::encode(value)), addressFor(dst));
>+        return;
>+    }
>+
>+    load64(addressFor(src), regT0);
>+    store64(regT0, addressFor(dst));
> }
> 
>

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