[webkit-changes] [WebKit/WebKit] c639ec: [JSC] Remove unnecessary mov when wasm function do...

[Yusuke Suzuki]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: c639ec2e4394bd044a4b737d470b3b5bc47062ab
      https://github.com/WebKit/WebKit/commit/c639ec2e4394bd044a4b737d470b3b5bc47062ab
  Author: Yusuke Suzuki <ysuzuki at apple.com>
  Date:   2022-12-22 (Thu, 22 Dec 2022)

  Changed paths:
    M Source/JavaScriptCore/b3/air/AirCode.cpp
    M Source/JavaScriptCore/wasm/WasmAirIRGenerator32_64.cpp
    M Source/JavaScriptCore/wasm/WasmAirIRGenerator64.cpp
    M Source/JavaScriptCore/wasm/WasmB3IRGenerator.cpp

  Log Message:
  -----------
  [JSC] Remove unnecessary mov when wasm function does not have frame
https://bugs.webkit.org/show_bug.cgi?id=249809
rdar://103649352

Reviewed by Justin Michaud and Mark Lam.

Air correctly optimizes function epilogue when there is no function frame (e.g. leaf function with zero stack usage).
However, Wasm Air / B3 generators do not use this Air Return opcode, and instead emitting suboptimal epilogue.
This patch fixes it so that we unify these epilogue implementation into AirCode::emitEpilogue.

* Source/JavaScriptCore/b3/air/AirCode.cpp:
(JSC::B3::Air::Code::emitEpilogue):
* Source/JavaScriptCore/wasm/WasmAirIRGenerator32_64.cpp:
(JSC::Wasm::AirIRGenerator32::addReturn):
* Source/JavaScriptCore/wasm/WasmAirIRGenerator64.cpp:
(JSC::Wasm::AirIRGenerator64::addReturn):
* Source/JavaScriptCore/wasm/WasmB3IRGenerator.cpp:
(JSC::Wasm::B3IRGenerator::addReturn):

Canonical link: https://commits.webkit.org/258264@main