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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "jni_compiler.h"
#include <sys/mman.h>
#include <vector>
#include "assembler.h"
#include "calling_convention.h"
#include "class_linker.h"
#include "compiled_method.h"
#include "constants.h"
#include "jni_internal.h"
#include "logging.h"
#include "macros.h"
#include "managed_register.h"
#include "thread.h"
#include "UniquePtr.h"
namespace art {
JniCompiler::JniCompiler(InstructionSet instruction_set) {
if (instruction_set == kThumb2) {
// currently only ARM code generation is supported
instruction_set_ = kArm;
} else {
instruction_set_ = instruction_set;
}
}
JniCompiler::~JniCompiler() {}
// Generate the JNI bridge for the given method, general contract:
// - Arguments are in the managed runtime format, either on stack or in
// registers, a reference to the method object is supplied as part of this
// convention.
//
CompiledMethod* JniCompiler::Compile(uint32_t access_flags, uint32_t method_idx,
const ClassLoader* class_loader, const DexFile& dex_file) {
CHECK((access_flags & kAccNative) != 0);
const bool is_static = (access_flags & kAccStatic) != 0;
const bool is_synchronized = (access_flags & kAccSynchronized) != 0;
const char* shorty = dex_file.GetMethodShorty(dex_file.GetMethodId(method_idx));
// Calling conventions used to iterate over parameters to method
UniquePtr<JniCallingConvention> jni_conv(
JniCallingConvention::Create(is_static, is_synchronized, shorty, instruction_set_));
UniquePtr<ManagedRuntimeCallingConvention> mr_conv(
ManagedRuntimeCallingConvention::Create(is_static, is_synchronized, shorty, instruction_set_));
// Assembler that holds generated instructions
UniquePtr<Assembler> jni_asm(Assembler::Create(instruction_set_));
#define __ jni_asm->
// Offsets into data structures
// TODO: if cross compiling these offsets are for the host not the target
const Offset functions(OFFSETOF_MEMBER(JNIEnvExt, functions));
const Offset monitor_enter(OFFSETOF_MEMBER(JNINativeInterface, MonitorEnter));
const Offset monitor_exit(OFFSETOF_MEMBER(JNINativeInterface, MonitorExit));
// 1. Build the frame saving all callee saves
const size_t frame_size(jni_conv->FrameSize());
const std::vector<ManagedRegister>& callee_save_regs = jni_conv->CalleeSaveRegisters();
__ BuildFrame(frame_size, mr_conv->MethodRegister(), callee_save_regs);
// 2. Set up the StackIndirectReferenceTable
mr_conv->ResetIterator(FrameOffset(frame_size));
jni_conv->ResetIterator(FrameOffset(0));
__ StoreImmediateToFrame(jni_conv->SirtNumRefsOffset(),
jni_conv->ReferenceCount(),
mr_conv->InterproceduralScratchRegister());
__ CopyRawPtrFromThread(jni_conv->SirtLinkOffset(),
Thread::TopSirtOffset(),
mr_conv->InterproceduralScratchRegister());
__ StoreStackOffsetToThread(Thread::TopSirtOffset(),
jni_conv->SirtOffset(),
mr_conv->InterproceduralScratchRegister());
// 3. Place incoming reference arguments into SIRT
jni_conv->Next(); // Skip JNIEnv*
// 3.5. Create Class argument for static methods out of passed method
if (is_static) {
FrameOffset sirt_offset = jni_conv->CurrentParamSirtEntryOffset();
// Check sirt offset is within frame
CHECK_LT(sirt_offset.Uint32Value(), frame_size);
__ LoadRef(jni_conv->InterproceduralScratchRegister(),
mr_conv->MethodRegister(), Method::DeclaringClassOffset());
__ VerifyObject(jni_conv->InterproceduralScratchRegister(), false);
__ StoreRef(sirt_offset, jni_conv->InterproceduralScratchRegister());
jni_conv->Next(); // in SIRT so move to next argument
}
while (mr_conv->HasNext()) {
CHECK(jni_conv->HasNext());
bool ref_param = jni_conv->IsCurrentParamAReference();
CHECK(!ref_param || mr_conv->IsCurrentParamAReference());
// References need placing in SIRT and the entry value passing
if (ref_param) {
// Compute SIRT entry, note null is placed in the SIRT but its boxed value
// must be NULL
FrameOffset sirt_offset = jni_conv->CurrentParamSirtEntryOffset();
// Check SIRT offset is within frame and doesn't run into the saved segment state
CHECK_LT(sirt_offset.Uint32Value(), frame_size);
CHECK_NE(sirt_offset.Uint32Value(),
jni_conv->SavedLocalReferenceCookieOffset().Uint32Value());
bool input_in_reg = mr_conv->IsCurrentParamInRegister();
bool input_on_stack = mr_conv->IsCurrentParamOnStack();
CHECK(input_in_reg || input_on_stack);
if (input_in_reg) {
ManagedRegister in_reg = mr_conv->CurrentParamRegister();
__ VerifyObject(in_reg, mr_conv->IsCurrentArgPossiblyNull());
__ StoreRef(sirt_offset, in_reg);
} else if (input_on_stack) {
FrameOffset in_off = mr_conv->CurrentParamStackOffset();
__ VerifyObject(in_off, mr_conv->IsCurrentArgPossiblyNull());
__ CopyRef(sirt_offset, in_off,
mr_conv->InterproceduralScratchRegister());
}
}
mr_conv->Next();
jni_conv->Next();
}
// 4. Transition from being in managed to native code. Save the top_of_managed_stack_
// so that the managed stack can be crawled while in native code. Clear the corresponding
// PC value that has no meaning for the this frame.
__ StoreStackPointerToThread(Thread::TopOfManagedStackOffset());
__ StoreImmediateToThread(Thread::TopOfManagedStackPcOffset(), 0,
mr_conv->InterproceduralScratchRegister());
ChangeThreadState(jni_asm.get(), Thread::kNative,
mr_conv->InterproceduralScratchRegister(),
ManagedRegister::NoRegister(), FrameOffset(0), 0);
// 5. Move frame down to allow space for out going args. Do for as short a
// time as possible to aid profiling..
const size_t out_arg_size = jni_conv->OutArgSize();
__ IncreaseFrameSize(out_arg_size);
// 6. Acquire lock for synchronized methods.
if (is_synchronized) {
// Compute arguments in registers to preserve
mr_conv->ResetIterator(FrameOffset(frame_size + out_arg_size));
std::vector<ManagedRegister> live_argument_regs;
while (mr_conv->HasNext()) {
if (mr_conv->IsCurrentParamInRegister()) {
live_argument_regs.push_back(mr_conv->CurrentParamRegister());
}
mr_conv->Next();
}
// Copy arguments to preserve to callee save registers
CHECK_LE(live_argument_regs.size(), callee_save_regs.size());
for (size_t i = 0; i < live_argument_regs.size(); i++) {
__ Move(callee_save_regs.at(i), live_argument_regs.at(i));
}
// Get SIRT entry for 1st argument (jclass or this) to be 1st argument to
// monitor enter
mr_conv->ResetIterator(FrameOffset(frame_size + out_arg_size));
jni_conv->ResetIterator(FrameOffset(out_arg_size));
jni_conv->Next(); // Skip JNIEnv*
if (is_static) {
FrameOffset sirt_offset = jni_conv->CurrentParamSirtEntryOffset();
if (jni_conv->IsCurrentParamOnStack()) {
FrameOffset out_off = jni_conv->CurrentParamStackOffset();
__ CreateSirtEntry(out_off, sirt_offset,
mr_conv->InterproceduralScratchRegister(),
false);
} else {
ManagedRegister out_reg = jni_conv->CurrentParamRegister();
__ CreateSirtEntry(out_reg, sirt_offset,
ManagedRegister::NoRegister(), false);
}
} else {
CopyParameter(jni_asm.get(), mr_conv.get(), jni_conv.get(), frame_size,
out_arg_size);
}
// Generate JNIEnv* in place and leave a copy in jni_fns_register
jni_conv->ResetIterator(FrameOffset(out_arg_size));
ManagedRegister jni_fns_register =
jni_conv->InterproceduralScratchRegister();
__ LoadRawPtrFromThread(jni_fns_register, Thread::JniEnvOffset());
SetNativeParameter(jni_asm.get(), jni_conv.get(), jni_fns_register);
// Call JNIEnv->MonitorEnter(object)
__ LoadRawPtr(jni_fns_register, jni_fns_register, functions);
__ Call(jni_fns_register, monitor_enter,
jni_conv->InterproceduralScratchRegister());
// Check for exceptions
__ ExceptionPoll(jni_conv->InterproceduralScratchRegister());
// Restore live arguments
for (size_t i = 0; i < live_argument_regs.size(); i++) {
__ Move(live_argument_regs.at(i), callee_save_regs.at(i));
}
}
// 7. Iterate over arguments placing values from managed calling convention in
// to the convention required for a native call (shuffling). For references
// place an index/pointer to the reference after checking whether it is
// NULL (which must be encoded as NULL).
// Note: we do this prior to materializing the JNIEnv* and static's jclass to
// give as many free registers for the shuffle as possible
mr_conv->ResetIterator(FrameOffset(frame_size+out_arg_size));
uint32_t args_count = 0;
while (mr_conv->HasNext()) {
args_count++;
mr_conv->Next();
}
// Do a backward pass over arguments, so that the generated code will be "mov
// R2, R3; mov R1, R2" instead of "mov R1, R2; mov R2, R3."
// TODO: A reverse iterator to improve readability.
for (uint32_t i = 0; i < args_count; ++i) {
mr_conv->ResetIterator(FrameOffset(frame_size + out_arg_size));
jni_conv->ResetIterator(FrameOffset(out_arg_size));
jni_conv->Next(); // Skip JNIEnv*
if (is_static) {
jni_conv->Next(); // Skip Class for now
}
for (uint32_t j = 0; j < args_count - i - 1; ++j) {
mr_conv->Next();
jni_conv->Next();
}
CopyParameter(jni_asm.get(), mr_conv.get(), jni_conv.get(), frame_size, out_arg_size);
}
if (is_static) {
// Create argument for Class
mr_conv->ResetIterator(FrameOffset(frame_size+out_arg_size));
jni_conv->ResetIterator(FrameOffset(out_arg_size));
jni_conv->Next(); // Skip JNIEnv*
FrameOffset sirt_offset = jni_conv->CurrentParamSirtEntryOffset();
if (jni_conv->IsCurrentParamOnStack()) {
FrameOffset out_off = jni_conv->CurrentParamStackOffset();
__ CreateSirtEntry(out_off, sirt_offset,
mr_conv->InterproceduralScratchRegister(),
false);
} else {
ManagedRegister out_reg = jni_conv->CurrentParamRegister();
__ CreateSirtEntry(out_reg, sirt_offset,
ManagedRegister::NoRegister(), false);
}
}
// 8. Create 1st argument, the JNI environment ptr and save the top of the local reference table
jni_conv->ResetIterator(FrameOffset(out_arg_size));
// Register that will hold local indirect reference table
if (jni_conv->IsCurrentParamInRegister()) {
ManagedRegister jni_env = jni_conv->CurrentParamRegister();
DCHECK(!jni_env.Equals(jni_conv->InterproceduralScratchRegister()));
__ LoadRawPtrFromThread(jni_env, Thread::JniEnvOffset());
// Frame[saved_local_ref_cookie_offset] = env->local_ref_cookie
__ Copy(jni_conv->SavedLocalReferenceCookieOffset(),
jni_env, JNIEnvExt::LocalRefCookieOffset(),
jni_conv->InterproceduralScratchRegister(), 4);
// env->local_ref_cookie = env->locals.segment_state
__ Copy(jni_env, JNIEnvExt::LocalRefCookieOffset(),
jni_env, JNIEnvExt::SegmentStateOffset(),
jni_conv->InterproceduralScratchRegister(), 4);
} else {
FrameOffset jni_env = jni_conv->CurrentParamStackOffset();
__ CopyRawPtrFromThread(jni_env, Thread::JniEnvOffset(),
jni_conv->InterproceduralScratchRegister());
// Frame[saved_local_ref_cookie_offset] = env->local_ref_cookie
__ Copy(jni_conv->SavedLocalReferenceCookieOffset(),
jni_env, JNIEnvExt::LocalRefCookieOffset(),
jni_conv->InterproceduralScratchRegister(), 4);
// env->local_ref_cookie = env->locals.segment_state
__ Copy(jni_env, JNIEnvExt::LocalRefCookieOffset(),
jni_env, JNIEnvExt::SegmentStateOffset(),
jni_conv->InterproceduralScratchRegister(), 4);
}
// 9. Plant call to native code associated with method
if (!jni_conv->IsMethodRegisterClobberedPreCall()) {
// Method register shouldn't have been crushed by setting up outgoing
// arguments
__ Call(mr_conv->MethodRegister(), Method::NativeMethodOffset(),
mr_conv->InterproceduralScratchRegister());
} else {
__ Call(jni_conv->MethodStackOffset(), Method::NativeMethodOffset(),
mr_conv->InterproceduralScratchRegister());
}
// 10. Release lock for synchronized methods.
if (is_synchronized) {
mr_conv->ResetIterator(FrameOffset(frame_size+out_arg_size));
jni_conv->ResetIterator(FrameOffset(out_arg_size));
jni_conv->Next(); // Skip JNIEnv*
// Save return value
FrameOffset return_save_location = jni_conv->ReturnValueSaveLocation();
if (jni_conv->SizeOfReturnValue() != 0) {
FrameOffset return_save_location = jni_conv->ReturnValueSaveLocation();
CHECK_LT(return_save_location.Uint32Value(), frame_size+out_arg_size);
__ Store(return_save_location, jni_conv->ReturnRegister(),
jni_conv->SizeOfReturnValue());
}
// Get SIRT entry for 1st argument
if (is_static) {
FrameOffset sirt_offset = jni_conv->CurrentParamSirtEntryOffset();
if (jni_conv->IsCurrentParamOnStack()) {
FrameOffset out_off = jni_conv->CurrentParamStackOffset();
__ CreateSirtEntry(out_off, sirt_offset,
mr_conv->InterproceduralScratchRegister(),
false);
} else {
ManagedRegister out_reg = jni_conv->CurrentParamRegister();
__ CreateSirtEntry(out_reg, sirt_offset,
ManagedRegister::NoRegister(), false);
}
} else {
CopyParameter(jni_asm.get(), mr_conv.get(), jni_conv.get(), frame_size,
out_arg_size);
}
// Generate JNIEnv* in place and leave a copy in jni_env_register
jni_conv->ResetIterator(FrameOffset(out_arg_size));
ManagedRegister jni_env_register =
jni_conv->InterproceduralScratchRegister();
__ LoadRawPtrFromThread(jni_env_register, Thread::JniEnvOffset());
SetNativeParameter(jni_asm.get(), jni_conv.get(), jni_env_register);
// Call JNIEnv->MonitorExit(object)
__ LoadRawPtr(jni_env_register, jni_env_register, functions);
__ Call(jni_env_register, monitor_exit,
jni_conv->InterproceduralScratchRegister());
// Reload return value
if (jni_conv->SizeOfReturnValue() != 0) {
__ Load(jni_conv->ReturnRegister(), return_save_location,
jni_conv->SizeOfReturnValue());
}
}
// 11. Release outgoing argument area
__ DecreaseFrameSize(out_arg_size);
mr_conv->ResetIterator(FrameOffset(frame_size));
jni_conv->ResetIterator(FrameOffset(0));
// 12. Transition from being in native to managed code, possibly entering a
// safepoint
// Don't clobber result
CHECK(!jni_conv->InterproceduralScratchRegister().Equals(jni_conv->ReturnRegister()));
// Location to preserve result on slow path, ensuring its within the frame
FrameOffset return_save_location = jni_conv->ReturnValueSaveLocation();
CHECK(return_save_location.Uint32Value() < frame_size ||
jni_conv->SizeOfReturnValue() == 0);
ChangeThreadState(jni_asm.get(), Thread::kRunnable,
jni_conv->InterproceduralScratchRegister(),
jni_conv->ReturnRegister(), return_save_location,
jni_conv->SizeOfReturnValue());
// 13. Place result in correct register possibly loading from indirect
// reference table
if (jni_conv->IsReturnAReference()) {
__ IncreaseFrameSize(out_arg_size);
jni_conv->ResetIterator(FrameOffset(out_arg_size));
jni_conv->Next(); // Skip Thread* argument
// Pass result as arg2
SetNativeParameter(jni_asm.get(), jni_conv.get(),
jni_conv->ReturnRegister());
// Pass Thread*
jni_conv->ResetIterator(FrameOffset(out_arg_size));
if (jni_conv->IsCurrentParamInRegister()) {
__ GetCurrentThread(jni_conv->CurrentParamRegister());
__ Call(jni_conv->CurrentParamRegister(),
Offset(OFFSETOF_MEMBER(Thread, pDecodeJObjectInThread)),
jni_conv->InterproceduralScratchRegister());
} else {
__ GetCurrentThread(jni_conv->CurrentParamStackOffset(),
jni_conv->InterproceduralScratchRegister());
__ Call(ThreadOffset(OFFSETOF_MEMBER(Thread, pDecodeJObjectInThread)),
jni_conv->InterproceduralScratchRegister());
}
__ DecreaseFrameSize(out_arg_size);
jni_conv->ResetIterator(FrameOffset(0));
}
__ Move(mr_conv->ReturnRegister(), jni_conv->ReturnRegister());
// 14. Restore segment state and remove SIRT from thread
{
ManagedRegister jni_env = jni_conv->InterproceduralScratchRegister();
__ LoadRawPtrFromThread(jni_env, Thread::JniEnvOffset());
// env->locals.segment_state = env->local_ref_cookie
__ Copy(jni_env, JNIEnvExt::SegmentStateOffset(),
jni_env, JNIEnvExt::LocalRefCookieOffset(),
jni_conv->ReturnScratchRegister(), 4);
// env->local_ref_cookie = Frame[saved_local_ref_cookie_offset]
__ Copy(jni_env, JNIEnvExt::LocalRefCookieOffset(),
jni_conv->SavedLocalReferenceCookieOffset(),
jni_conv->ReturnScratchRegister(), 4);
}
__ CopyRawPtrToThread(Thread::TopSirtOffset(), jni_conv->SirtLinkOffset(),
jni_conv->InterproceduralScratchRegister());
// 15. Check for pending exception and forward if there
__ ExceptionPoll(jni_conv->InterproceduralScratchRegister());
// 16. Remove activation
if (is_synchronized) {
__ RemoveFrame(frame_size, callee_save_regs);
} else {
// no need to restore callee save registers because we didn't
// clobber them while locking the monitor.
__ RemoveFrame(frame_size, std::vector<ManagedRegister>());
}
// 17. Finalize code generation
__ EmitSlowPaths();
size_t cs = __ CodeSize();
std::vector<uint8_t> managed_code(cs);
MemoryRegion code(&managed_code[0], managed_code.size());
__ FinalizeInstructions(code);
return new CompiledMethod(instruction_set_,
managed_code,
frame_size,
jni_conv->CoreSpillMask(),
jni_conv->FpSpillMask());
#undef __
}
void JniCompiler::SetNativeParameter(Assembler* jni_asm,
JniCallingConvention* jni_conv,
ManagedRegister in_reg) {
#define __ jni_asm->
if (jni_conv->IsCurrentParamOnStack()) {
FrameOffset dest = jni_conv->CurrentParamStackOffset();
__ StoreRawPtr(dest, in_reg);
} else {
if (!jni_conv->CurrentParamRegister().Equals(in_reg)) {
__ Move(jni_conv->CurrentParamRegister(), in_reg);
}
}
#undef __
}
// Copy a single parameter from the managed to the JNI calling convention
void JniCompiler::CopyParameter(Assembler* jni_asm,
ManagedRuntimeCallingConvention* mr_conv,
JniCallingConvention* jni_conv,
size_t frame_size, size_t out_arg_size) {
bool input_in_reg = mr_conv->IsCurrentParamInRegister();
bool output_in_reg = jni_conv->IsCurrentParamInRegister();
FrameOffset sirt_offset(0);
bool null_allowed = false;
bool ref_param = jni_conv->IsCurrentParamAReference();
CHECK(!ref_param || mr_conv->IsCurrentParamAReference());
// input may be in register, on stack or both - but not none!
CHECK(input_in_reg || mr_conv->IsCurrentParamOnStack());
if (output_in_reg) { // output shouldn't straddle registers and stack
CHECK(!jni_conv->IsCurrentParamOnStack());
} else {
CHECK(jni_conv->IsCurrentParamOnStack());
}
// References need placing in SIRT and the entry address passing
if (ref_param) {
null_allowed = mr_conv->IsCurrentArgPossiblyNull();
// Compute SIRT offset. Note null is placed in the SIRT but the jobject
// passed to the native code must be null (not a pointer into the SIRT
// as with regular references).
sirt_offset = jni_conv->CurrentParamSirtEntryOffset();
// Check SIRT offset is within frame.
CHECK_LT(sirt_offset.Uint32Value(), (frame_size + out_arg_size));
}
#define __ jni_asm->
if (input_in_reg && output_in_reg) {
ManagedRegister in_reg = mr_conv->CurrentParamRegister();
ManagedRegister out_reg = jni_conv->CurrentParamRegister();
if (ref_param) {
__ CreateSirtEntry(out_reg, sirt_offset, in_reg, null_allowed);
} else {
if (!mr_conv->IsCurrentParamOnStack()) {
// regular non-straddling move
__ Move(out_reg, in_reg);
} else {
UNIMPLEMENTED(FATAL); // we currently don't expect to see this case
}
}
} else if (!input_in_reg && !output_in_reg) {
FrameOffset out_off = jni_conv->CurrentParamStackOffset();
if (ref_param) {
__ CreateSirtEntry(out_off, sirt_offset, mr_conv->InterproceduralScratchRegister(),
null_allowed);
} else {
FrameOffset in_off = mr_conv->CurrentParamStackOffset();
size_t param_size = mr_conv->CurrentParamSize();
CHECK_EQ(param_size, jni_conv->CurrentParamSize());
__ Copy(out_off, in_off, mr_conv->InterproceduralScratchRegister(), param_size);
}
} else if (!input_in_reg && output_in_reg) {
FrameOffset in_off = mr_conv->CurrentParamStackOffset();
ManagedRegister out_reg = jni_conv->CurrentParamRegister();
// Check that incoming stack arguments are above the current stack frame.
CHECK_GT(in_off.Uint32Value(), frame_size);
if (ref_param) {
__ CreateSirtEntry(out_reg, sirt_offset, ManagedRegister::NoRegister(), null_allowed);
} else {
size_t param_size = mr_conv->CurrentParamSize();
CHECK_EQ(param_size, jni_conv->CurrentParamSize());
__ Load(out_reg, in_off, param_size);
}
} else {
CHECK(input_in_reg && !output_in_reg);
ManagedRegister in_reg = mr_conv->CurrentParamRegister();
FrameOffset out_off = jni_conv->CurrentParamStackOffset();
// Check outgoing argument is within frame
CHECK_LT(out_off.Uint32Value(), frame_size);
if (ref_param) {
// TODO: recycle value in in_reg rather than reload from SIRT
__ CreateSirtEntry(out_off, sirt_offset, mr_conv->InterproceduralScratchRegister(),
null_allowed);
} else {
size_t param_size = mr_conv->CurrentParamSize();
CHECK_EQ(param_size, jni_conv->CurrentParamSize());
if (!mr_conv->IsCurrentParamOnStack()) {
// regular non-straddling store
__ Store(out_off, in_reg, param_size);
} else {
// store where input straddles registers and stack
CHECK_EQ(param_size, 8u);
FrameOffset in_off = mr_conv->CurrentParamStackOffset();
__ StoreSpanning(out_off, in_reg, in_off, mr_conv->InterproceduralScratchRegister());
}
}
}
#undef __
}
void JniCompiler::ChangeThreadState(Assembler* jni_asm, Thread::State new_state,
ManagedRegister scratch, ManagedRegister return_reg,
FrameOffset return_save_location,
size_t return_size) {
/*
* This code mirrors that of Thread::SetState where detail is given on why
* barriers occur when they do.
*/
#define __ jni_asm->
if (new_state == Thread::kRunnable) {
/*
* Change our status to Thread::kRunnable. The transition requires
* that we check for pending suspension, because the VM considers
* us to be "asleep" in all other states, and another thread could
* be performing a GC now.
*/
__ StoreImmediateToThread(Thread::StateOffset(), Thread::kRunnable, scratch);
__ MemoryBarrier(scratch);
__ SuspendPoll(scratch, return_reg, return_save_location, return_size);
} else {
/*
* Not changing to Thread::kRunnable. No additional work required.
*/
__ MemoryBarrier(scratch);
__ StoreImmediateToThread(Thread::StateOffset(), new_state, scratch);
}
#undef __
}
} // namespace art