darling-JavaScriptCore/assembler/ProbeContext.cpp
2020-08-29 15:28:47 -04:00

89 lines
3.1 KiB
C++

/*
* Copyright (C) 2017 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "ProbeContext.h"
#if ENABLE(MASM_PROBE)
namespace JSC {
namespace Probe {
static void flushDirtyStackPages(State*);
void executeProbe(State* state)
{
Context context(state);
#if CPU(ARM64)
auto& cpu = context.cpu;
void* originalLR = cpu.gpr<void*>(ARM64Registers::lr);
void* originalPC = cpu.pc();
#elif CPU(MIPS)
auto& cpu = context.cpu;
void* originalRA = cpu.gpr<void*>(MIPSRegisters::ra);
void* originalPC = cpu.pc();
#endif
state->initializeStackFunction = nullptr;
state->initializeStackArg = nullptr;
state->probeFunction(context);
#if CPU(ARM64)
// The ARM64 probe trampoline does not support changing both lr and pc.
RELEASE_ASSERT(originalPC == cpu.pc() || originalLR == cpu.gpr<void*>(ARM64Registers::lr));
#elif CPU(MIPS)
// The MIPS probe trampoline does not support changing both ra and pc.
RELEASE_ASSERT(originalPC == cpu.pc() || originalRA == cpu.gpr<void*>(MIPSRegisters::ra));
#endif
if (context.hasWritesToFlush()) {
context.stack().setSavedStackPointer(state->cpu.sp());
void* lowWatermark = context.stack().lowWatermarkFromVisitingDirtyPages();
state->cpu.sp() = std::min(lowWatermark, state->cpu.sp());
state->initializeStackFunction = flushDirtyStackPages;
state->initializeStackArg = context.releaseStack();
}
}
static void flushDirtyStackPages(State* state)
{
std::unique_ptr<Stack> stack(reinterpret_cast<Probe::Stack*>(state->initializeStackArg));
stack->flushWrites();
state->cpu.sp() = stack->savedStackPointer();
}
// Not for general use. This should only be for writing tests.
JS_EXPORT_PRIVATE void* probeStateForContext(Context&);
void* probeStateForContext(Context& context)
{
return context.m_state;
}
} // namespace Probe
} // namespace JSC
#endif // ENABLE(MASM_PROBE)