dart-sdk/runtime/vm/ffi_callback_trampolines.cc
Ryan Macnak bc43e97b74 [vm] Place only Dart heap pages in the 4GB compressible region.
Don't allocate zones, timeline events or profile samples in the compressible region, since these allocations don't yeild compressed pointers and are competing for a limited resource.

TEST=ci
Bug: b/196510517
Change-Id: I4fc2f0d67060f927fa10d241b15b1cae3b73d919
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/212400
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
2021-09-08 01:16:57 +00:00

109 lines
3.7 KiB
C++

// Copyright (c) 2019, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "vm/ffi_callback_trampolines.h"
#if !defined(DART_PRECOMPILED_RUNTIME)
#include "vm/code_comments.h"
#include "vm/code_observers.h"
#include "vm/compiler/assembler/assembler.h"
#include "vm/compiler/assembler/disassembler.h"
#include "vm/exceptions.h"
#endif // !defined(DART_PRECOMPILED_RUNTIME)
namespace dart {
#if !defined(DART_PRECOMPILED_RUNTIME)
uword NativeCallbackTrampolines::TrampolineForId(int32_t callback_id) {
#if defined(DART_PRECOMPILER)
ASSERT(!Enabled());
UNREACHABLE();
#else
const intptr_t trampolines_per_page = NumCallbackTrampolinesPerPage();
const intptr_t page_index = callback_id / trampolines_per_page;
const uword entry_point = trampoline_pages_[page_index]->start();
return entry_point +
(callback_id % trampolines_per_page) *
compiler::StubCodeCompiler::kNativeCallbackTrampolineSize;
#endif
}
void NativeCallbackTrampolines::AllocateTrampoline() {
#if defined(DART_PRECOMPILER)
ASSERT(!Enabled());
UNREACHABLE();
#else
// Callback IDs are limited to 32-bits for trampoline compactness.
if (kWordSize == 8 &&
!Utils::IsInt(32, next_callback_id_ + NumCallbackTrampolinesPerPage())) {
Exceptions::ThrowOOM();
}
if (trampolines_left_on_page_ == 0) {
// Fuchsia requires memory to be allocated with ZX_RIGHT_EXECUTE in order
// to be flipped to kReadExecute after being kReadWrite.
VirtualMemory* const memory = VirtualMemory::AllocateAligned(
/*size=*/VirtualMemory::PageSize(),
/*alignment=*/VirtualMemory::PageSize(),
/*is_executable=*/true,
/*is_compressed=*/false,
/*name=*/"Dart VM FFI callback trampolines");
memory->Protect(VirtualMemory::kReadWrite);
if (memory == nullptr) {
Exceptions::ThrowOOM();
}
trampoline_pages_.Add(memory);
compiler::Assembler assembler(/*object_pool_builder=*/nullptr);
compiler::StubCodeCompiler::GenerateJITCallbackTrampolines(
&assembler, next_callback_id_);
MemoryRegion region(memory->address(), memory->size());
assembler.FinalizeInstructions(region);
memory->Protect(VirtualMemory::kReadExecute);
#if !defined(PRODUCT)
const char* name = "FfiJitCallbackTrampolines";
ASSERT(!Thread::Current()->IsAtSafepoint());
if (CodeObservers::AreActive()) {
const auto& comments = CreateCommentsFrom(&assembler);
CodeObservers::NotifyAll(name,
/*base=*/memory->start(),
/*prologue_offset=*/0,
/*size=*/assembler.CodeSize(),
/*optimized=*/false, // not really relevant
&comments);
}
#endif
#if !defined(PRODUCT) || defined(FORCE_INCLUDE_DISASSEMBLER)
if (FLAG_disassemble_stubs && FLAG_support_disassembler) {
DisassembleToStdout formatter;
THR_Print(
"Code for native callback trampolines "
"[%" Pd " -> %" Pd "]: {\n",
next_callback_id_,
next_callback_id_ + NumCallbackTrampolinesPerPage() - 1);
const auto& comments = CreateCommentsFrom(&assembler);
Disassembler::Disassemble(memory->start(),
memory->start() + assembler.CodeSize(),
&formatter, &comments);
}
#endif
trampolines_left_on_page_ = NumCallbackTrampolinesPerPage();
}
trampolines_left_on_page_--;
next_callback_id_++;
#endif // defined(DART_PRECOMPILER)
}
#endif // !defined(DART_PRECOMPILED_RUNTIME)
} // namespace dart