testsJit.cpp - mozsearch

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-

 * vim: set ts=8 sts=2 et sw=2 tw=80:

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "jsapi-tests/testsJit.h"

#include "jit/JitCommon.h"

#include "jit/Linker.h"

#include "jit/MacroAssembler-inl.h"

// On entry to the JIT code, save every register.

void PrepareJit(js::jit::MacroAssembler& masm) {

  using namespace js::jit;

#if defined(JS_CODEGEN_ARM64)

  masm.Mov(PseudoStackPointer64, sp);

  masm.SetStackPointer64(PseudoStackPointer64);

#endif

  AllocatableRegisterSet regs(RegisterSet::All());

  LiveRegisterSet save(regs.asLiveSet());

#if defined(JS_CODEGEN_ARM)

  save.add(js::jit::d15);

#endif

#if defined(JS_CODEGEN_MIPS64) || defined(JS_CODEGEN_LOONG64) || \

    defined(JS_CODEGEN_RISCV64)

  save.add(js::jit::ra);

#elif defined(JS_USE_LINK_REGISTER)

  save.add(js::jit::lr);

#endif

  masm.PushRegsInMask(save);

// Generate the exit path of the JIT code, which restores every register. Then,

// make it executable and run it.

bool ExecuteJit(JSContext* cx, js::jit::MacroAssembler& masm) {

  using namespace js::jit;

  AllocatableRegisterSet regs(RegisterSet::All());

  LiveRegisterSet restore(regs.asLiveSet());

#if defined(JS_CODEGEN_ARM)

  restore.add(js::jit::d15);

#endif

#if defined(JS_CODEGEN_MIPS64) || defined(JS_CODEGEN_LOONG64) || \

    defined(JS_CODEGEN_RISCV64)

  restore.add(js::jit::ra);

#elif defined(JS_USE_LINK_REGISTER)

  restore.add(js::jit::lr);

#endif

  masm.PopRegsInMask(restore);

#if defined(JS_CODEGEN_ARM64)

  // Return using the value popped into x30.

  masm.abiret();

  // Reset stack pointer.

  masm.SetStackPointer64(PseudoStackPointer64);

#else

  // Exit the JIT-ed code using the ABI return style.

  masm.abiret();

#endif

  if (masm.oom()) {

    return false;

  JitCode* code = nullptr;

    Linker linker(masm);

    code = linker.newCode(cx, CodeKind::Other);

    if (!code) {

      return false;

  JS::AutoSuppressGCAnalysis suppress;

  EnterTest test = code->as<EnterTest>();

#if defined(JS_CODEGEN_ARM64) && !defined(JS_SIMULATOR_ARM64)

    // On arm64, we need to save/restore x28 -- the PSP -- across the call.

//

    // This cannot be done

//

    // * in the generated code, where both SP and PSP are in play; it is too

    //   confusing and difficult

//

    // * by adding x28 to the `save`/`restore` sets above, since they are

    //   subsequently processed by masm.{Push/Pop}RegsInMask and that refuses

    //   to deal with PSP.

//

    // So we do it here instead.  This relies on the (unchecked) assumption

    // that CALL_GENERATED_0 (and whatever it calls) does not place a value in

    // x28 that is needed after the call.

    MOZ_RELEASE_ASSERT(PseudoStackPointer64.code() == 28);

    uintptr_t savedX28;

    __asm__ __volatile__("str x28, %0" : : "m"(savedX28) : "cc", "memory");

    CALL_GENERATED_0(test);

    __asm__ __volatile__("ldr x28, %0" : : "m"(savedX28) : "cc", "memory");

#else

  CALL_GENERATED_0(test);

#endif

  return true;