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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_internal.h"
#include <algorithm>
#include "asm_support.h"
#include "assembler.h"
#include "compiled_method.h"
#include "object.h"
namespace art {
namespace arm {
// Creates a function which invokes a managed method with an array of
// arguments.
//
// At the time of call, the environment looks something like this:
//
// R0 = method pointer
// R1 = receiver pointer or NULL for static methods
// R2 = (managed) thread pointer
// R3 = argument array or NULL for no argument methods
// [SP] = JValue* result or NULL for void returns
//
// As the JNI call has already transitioned the thread into the
// "running" state the remaining responsibilities of this routine are
// to save the native register value and restore the managed thread
// register and transfer arguments from the array into register and on
// the stack, if needed. On return, the thread register must be
// shuffled and the return value must be store into the result JValue.
CompiledInvokeStub* ArmCreateInvokeStub(bool is_static, const char* shorty) {
UniquePtr<ArmAssembler> assembler(
down_cast<ArmAssembler*>(Assembler::Create(kArm)));
#define __ assembler->
size_t num_arg_array_bytes = NumArgArrayBytes(shorty);
// Size of frame - spill of R4,R9/LR + Method* + possible receiver + arg array
size_t unpadded_frame_size = (4 * kPointerSize) +
(is_static ? 0 : kPointerSize) +
num_arg_array_bytes;
size_t frame_size = RoundUp(unpadded_frame_size, kStackAlignment);
// Spill R4,R9 and LR
RegList save = (1 << R9) | (1 << R4);
__ PushList(save | (1 << LR));
// Move the managed thread pointer into R9.
__ mov(R9, ShifterOperand(R2));
// Reset R4 to suspend check interval
__ LoadImmediate(R4, SUSPEND_CHECK_INTERVAL);
// Move frame down for arguments less 3 pushed values above
__ AddConstant(SP, -frame_size + (3 * kPointerSize));
// Can either get 3 or 2 arguments into registers
size_t reg_bytes = (is_static ? 3 : 2) * kPointerSize;
// Bytes passed by stack
size_t stack_bytes;
if (num_arg_array_bytes > reg_bytes) {
stack_bytes = num_arg_array_bytes - reg_bytes;
} else {
stack_bytes = 0;
reg_bytes = num_arg_array_bytes;
}
// Method* at bottom of frame is null thereby terminating managed stack crawls
__ LoadImmediate(IP, 0, AL);
__ StoreToOffset(kStoreWord, IP, SP, 0);
// Copy values by stack
for (size_t off = 0; off < stack_bytes; off += kPointerSize) {
// we're displaced off of r3 by bytes that'll go in registers
int r3_offset = reg_bytes + off;
__ LoadFromOffset(kLoadWord, IP, R3, r3_offset);
// we're displaced off of the arguments by the spill space for the incoming
// arguments, the Method* and possibly the receiver
int sp_offset = reg_bytes + (is_static ? 1 : 2) * kPointerSize + off;
__ StoreToOffset(kStoreWord, IP, SP, sp_offset);
}
// Move all the register arguments into place.
if (is_static) {
if (reg_bytes > 0) {
__ LoadFromOffset(kLoadWord, R1, R3, 0);
if (reg_bytes > 4) {
__ LoadFromOffset(kLoadWord, R2, R3, 4);
if (reg_bytes > 8) {
__ LoadFromOffset(kLoadWord, R3, R3, 8);
}
}
}
} else {
if (reg_bytes > 0) {
__ LoadFromOffset(kLoadWord, R2, R3, 0);
if (reg_bytes > 4) {
__ LoadFromOffset(kLoadWord, R3, R3, 4);
}
}
}
// Load the code pointer we are about to call.
__ LoadFromOffset(kLoadWord, IP, R0, Method::GetCodeOffset().Int32Value());
// Do the call.
__ blx(IP);
// If the method returns a value, store it to the result pointer.
if (shorty[0] != 'V') {
// Load the result JValue pointer of the stub caller's out args.
__ LoadFromOffset(kLoadWord, IP, SP, frame_size);
StoreOperandType type = (shorty[0] == 'J' || shorty[0] == 'D') ? kStoreWordPair : kStoreWord;
__ StoreToOffset(type, R0, IP, 0);
}
// Remove the frame less the spilled R4, R9 and LR
__ AddConstant(SP, frame_size - (3 * kPointerSize));
// Pop R4, R9 and the LR into PC
__ PopList(save | (1 << PC));
// TODO: store native_entry in the stub table
std::vector<uint8_t> code(assembler->CodeSize());
MemoryRegion region(&code[0], code.size());
assembler->FinalizeInstructions(region);
return new CompiledInvokeStub(code);
#undef __
}
} // namespace arm
} // namespace art
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