JDK14/Java14源码在线阅读
/*
* Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*
*/
#include "precompiled.hpp"
#include "asm/assembler.hpp"
#include "asm/assembler.inline.hpp"
#include "asm/macroAssembler.hpp"
#include "ci/ciEnv.hpp"
#include "code/nativeInst.hpp"
#include "compiler/disassembler.hpp"
#include "gc/shared/barrierSet.hpp"
#include "gc/shared/cardTable.hpp"
#include "gc/shared/barrierSetAssembler.hpp"
#include "gc/shared/cardTableBarrierSet.hpp"
#include "gc/shared/collectedHeap.inline.hpp"
#include "interpreter/interpreter.hpp"
#include "memory/resourceArea.hpp"
#include "oops/accessDecorators.hpp"
#include "oops/klass.inline.hpp"
#include "prims/methodHandles.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/objectMonitor.hpp"
#include "runtime/os.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "utilities/macros.hpp"
// Implementation of AddressLiteral
void AddressLiteral::set_rspec(relocInfo::relocType rtype) {
switch (rtype) {
case relocInfo::oop_type:
// Oops are a special case. Normally they would be their own section
// but in cases like icBuffer they are literals in the code stream that
// we don't have a section for. We use none so that we get a literal address
// which is always patchable.
break;
case relocInfo::external_word_type:
_rspec = external_word_Relocation::spec(_target);
break;
case relocInfo::internal_word_type:
_rspec = internal_word_Relocation::spec(_target);
break;
case relocInfo::opt_virtual_call_type:
_rspec = opt_virtual_call_Relocation::spec();
break;
case relocInfo::static_call_type:
_rspec = static_call_Relocation::spec();
break;
case relocInfo::runtime_call_type:
_rspec = runtime_call_Relocation::spec();
break;
case relocInfo::poll_type:
case relocInfo::poll_return_type:
_rspec = Relocation::spec_simple(rtype);
break;
case relocInfo::none:
break;
default:
ShouldNotReachHere();
break;
}
}
// Initially added to the Assembler interface as a pure virtual:
// RegisterConstant delayed_value(..)
// for:
// 6812678 macro assembler needs delayed binding of a few constants (for 6655638)
// this was subsequently modified to its present name and return type
RegisterOrConstant MacroAssembler::delayed_value_impl(intptr_t* delayed_value_addr,
Register tmp,
int offset) {
ShouldNotReachHere();
return RegisterOrConstant(-1);
}
// virtual method calling
void MacroAssembler::lookup_virtual_method(Register recv_klass,
Register vtable_index,
Register method_result) {
const int base_offset = in_bytes(Klass::vtable_start_offset()) + vtableEntry::method_offset_in_bytes();
assert(vtableEntry::size() * wordSize == wordSize, "adjust the scaling in the code below");
add(recv_klass, recv_klass, AsmOperand(vtable_index, lsl, LogBytesPerWord));
ldr(method_result, Address(recv_klass, base_offset));
}
// Simplified, combined version, good for typical uses.
// Falls through on failure.
void MacroAssembler::check_klass_subtype(Register sub_klass,
Register super_klass,
Register temp_reg,
Register temp_reg2,
Register temp_reg3,
Label& L_success) {
Label L_failure;
check_klass_subtype_fast_path(sub_klass, super_klass, temp_reg, temp_reg2, &L_success, &L_failure, NULL);
check_klass_subtype_slow_path(sub_klass, super_klass, temp_reg, temp_reg2, temp_reg3, &L_success, NULL);
bind(L_failure);
};
void MacroAssembler::check_klass_subtype_fast_path(Register sub_klass,
Register super_klass,
Register temp_reg,
Register temp_reg2,
Label* L_success,
Label* L_failure,
Label* L_slow_path) {
assert_different_registers(sub_klass, super_klass, temp_reg, temp_reg2, noreg);
const Register super_check_offset = temp_reg2;
Label L_fallthrough;
int label_nulls = 0;
if (L_success == NULL) { L_success = &L_fallthrough; label_nulls++; }
if (L_failure == NULL) { L_failure = &L_fallthrough; label_nulls++; }
if (L_slow_path == NULL) { L_slow_path = &L_fallthrough; label_nulls++; }
assert(label_nulls <= 1, "at most one NULL in the batch");
int sc_offset = in_bytes(Klass::secondary_super_cache_offset());
int sco_offset = in_bytes(Klass::super_check_offset_offset());
Address super_check_offset_addr(super_klass, sco_offset);
// If the pointers are equal, we are done (e.g., String[] elements).
// This self-check enables sharing of secondary supertype arrays among
// non-primary types such as array-of-interface. Otherwise, each such
// type would need its own customized SSA.
// We move this check to the front of the fast path because many
// type checks are in fact trivially successful in this manner,
// so we get a nicely predicted branch right at the start of the check.
cmp(sub_klass, super_klass);
b(*L_success, eq);
// Check the supertype display:
ldr_u32(super_check_offset, super_check_offset_addr);
Address super_check_addr(sub_klass, super_check_offset);
ldr(temp_reg, super_check_addr);
cmp(super_klass, temp_reg); // load displayed supertype
// This check has worked decisively for primary supers.
// Secondary supers are sought in the super_cache ('super_cache_addr').
// (Secondary supers are interfaces and very deeply nested subtypes.)
// This works in the same check above because of a tricky aliasing
// between the super_cache and the primary super display elements.
// (The 'super_check_addr' can address either, as the case requires.)
// Note that the cache is updated below if it does not help us find
// what we need immediately.
// So if it was a primary super, we can just fail immediately.
// Otherwise, it's the slow path for us (no success at this point).
b(*L_success, eq);
cmp_32(super_check_offset, sc_offset);
if (L_failure == &L_fallthrough) {
b(*L_slow_path, eq);
} else {
b(*L_failure, ne);
if (L_slow_path != &L_fallthrough) {
b(*L_slow_path);
}
}
bind(L_fallthrough);
}
void MacroAssembler::check_klass_subtype_slow_path(Register sub_klass,
Register super_klass,
Register temp_reg,
Register temp2_reg,
Register temp3_reg,
Label* L_success,
Label* L_failure,
bool set_cond_codes) {
// Note: if used by code that expects a register to be 0 on success,
// this register must be temp_reg and set_cond_codes must be true
Register saved_reg = noreg;
// get additional tmp registers
if (temp3_reg == noreg) {
saved_reg = temp3_reg = LR;
push(saved_reg);
}
assert(temp2_reg != noreg, "need all the temporary registers");
assert_different_registers(sub_klass, super_klass, temp_reg, temp2_reg, temp3_reg);
Register cmp_temp = temp_reg;
Register scan_temp = temp3_reg;
Register count_temp = temp2_reg;
Label L_fallthrough;
int label_nulls = 0;
if (L_success == NULL) { L_success = &L_fallthrough; label_nulls++; }
if (L_failure == NULL) { L_failure = &L_fallthrough; label_nulls++; }
assert(label_nulls <= 1, "at most one NULL in the batch");
// a couple of useful fields in sub_klass:
int ss_offset = in_bytes(Klass::secondary_supers_offset());
int sc_offset = in_bytes(Klass::secondary_super_cache_offset());
Address secondary_supers_addr(sub_klass, ss_offset);
Address super_cache_addr( sub_klass, sc_offset);
#ifndef PRODUCT
inc_counter((address)&SharedRuntime::_partial_subtype_ctr, scan_temp, count_temp);
#endif
// We will consult the secondary-super array.
ldr(scan_temp, Address(sub_klass, ss_offset));
assert(! UseCompressedOops, "search_key must be the compressed super_klass");
// else search_key is the
Register search_key = super_klass;
// Load the array length.
ldr(count_temp, Address(scan_temp, Array<Klass*>::length_offset_in_bytes()));
add(scan_temp, scan_temp, Array<Klass*>::base_offset_in_bytes());
add(count_temp, count_temp, 1);
Label L_loop, L_fail;
// Top of search loop
bind(L_loop);
// Notes:
// scan_temp starts at the array elements
// count_temp is 1+size
subs(count_temp, count_temp, 1);
if ((L_failure != &L_fallthrough) && (! set_cond_codes) && (saved_reg == noreg)) {
// direct jump to L_failure if failed and no cleanup needed
b(*L_failure, eq); // not found and
} else {
b(L_fail, eq); // not found in the array
}
// Load next super to check
// In the array of super classes elements are pointer sized.
int element_size = wordSize;
ldr(cmp_temp, Address(scan_temp, element_size, post_indexed));
// Look for Rsuper_klass on Rsub_klass's secondary super-class-overflow list
subs(cmp_temp, cmp_temp, search_key);
// A miss means we are NOT a subtype and need to keep looping
b(L_loop, ne);
// Falling out the bottom means we found a hit; we ARE a subtype
// Note: temp_reg/cmp_temp is already 0 and flag Z is set
// Success. Cache the super we found and proceed in triumph.
str(super_klass, Address(sub_klass, sc_offset));
if (saved_reg != noreg) {
// Return success
pop(saved_reg);
}
b(*L_success);
bind(L_fail);
// Note1: check "b(*L_failure, eq)" above if adding extra instructions here
if (set_cond_codes) {
movs(temp_reg, sub_klass); // clears Z and sets temp_reg to non-0 if needed
}
if (saved_reg != noreg) {
pop(saved_reg);
}
if (L_failure != &L_fallthrough) {
b(*L_failure);
}
bind(L_fallthrough);
}
// Returns address of receiver parameter, using tmp as base register. tmp and params_count can be the same.
Address MacroAssembler::receiver_argument_address(Register params_base, Register params_count, Register tmp) {
assert_different_registers(params_base, params_count);
add(tmp, params_base, AsmOperand(params_count, lsl, Interpreter::logStackElementSize));
return Address(tmp, -Interpreter::stackElementSize);
}
void MacroAssembler::align(int modulus) {
while (offset() % modulus != 0) {
nop();
}
}
int MacroAssembler::set_last_Java_frame(Register last_java_sp,
Register last_java_fp,
bool save_last_java_pc,
Register tmp) {
int pc_offset;
if (last_java_fp != noreg) {
// optional
str(last_java_fp, Address(Rthread, JavaThread::last_Java_fp_offset()));
_fp_saved = true;
} else {
_fp_saved = false;
}
if (save_last_java_pc) {
str(PC, Address(Rthread, JavaThread::last_Java_pc_offset()));
pc_offset = offset() + VM_Version::stored_pc_adjustment();
_pc_saved = true;
} else {
_pc_saved = false;
pc_offset = -1;
}
// According to comment in javaFrameAnchorm SP must be saved last, so that other
// entries are valid when SP is set.
// However, this is probably not a strong constrainst since for instance PC is
// sometimes read from the stack at SP... but is pushed later (by the call). Hence,
// we now write the fields in the expected order but we have not added a StoreStore
// barrier.
// XXX: if the ordering is really important, PC should always be saved (without forgetting
// to update oop_map offsets) and a StoreStore barrier might be needed.
if (last_java_sp == noreg) {
last_java_sp = SP; // always saved
}
str(last_java_sp, Address(Rthread, JavaThread::last_Java_sp_offset()));
return pc_offset; // for oopmaps
}
void MacroAssembler::reset_last_Java_frame(Register tmp) {
const Register Rzero = zero_register(tmp);
str(Rzero, Address(Rthread, JavaThread::last_Java_sp_offset()));
if (_fp_saved) {
str(Rzero, Address(Rthread, JavaThread::last_Java_fp_offset()));
}
if (_pc_saved) {
str(Rzero, Address(Rthread, JavaThread::last_Java_pc_offset()));
}
}
// Implementation of call_VM versions
void MacroAssembler::call_VM_leaf_helper(address entry_point, int number_of_arguments) {
assert(number_of_arguments >= 0, "cannot have negative number of arguments");
assert(number_of_arguments <= 4, "cannot have more than 4 arguments");
// Safer to save R9 here since callers may have been written
// assuming R9 survives. This is suboptimal but is not worth
// optimizing for the few platforms where R9 is scratched.
push(RegisterSet(R4) | R9ifScratched);
mov(R4, SP);
bic(SP, SP, StackAlignmentInBytes - 1);
call(entry_point, relocInfo::runtime_call_type);
mov(SP, R4);
pop(RegisterSet(R4) | R9ifScratched);
}
void MacroAssembler::call_VM_helper(Register oop_result, address entry_point, int number_of_arguments, bool check_exceptions) {
assert(number_of_arguments >= 0, "cannot have negative number of arguments");
assert(number_of_arguments <= 3, "cannot have more than 3 arguments");
const Register tmp = Rtemp;
assert_different_registers(oop_result, tmp);
set_last_Java_frame(SP, FP, true, tmp);
#if R9_IS_SCRATCHED
// Safer to save R9 here since callers may have been written
// assuming R9 survives. This is suboptimal but is not worth
// optimizing for the few platforms where R9 is scratched.
// Note: cannot save R9 above the saved SP (some calls expect for
// instance the Java stack top at the saved SP)
// => once saved (with set_last_Java_frame), decrease SP before rounding to
// ensure the slot at SP will be free for R9).
sub(SP, SP, 4);
bic(SP, SP, StackAlignmentInBytes - 1);
str(R9, Address(SP, 0));
#else
bic(SP, SP, StackAlignmentInBytes - 1);
#endif // R9_IS_SCRATCHED
mov(R0, Rthread);
call(entry_point, relocInfo::runtime_call_type);
#if R9_IS_SCRATCHED
ldr(R9, Address(SP, 0));
#endif
ldr(SP, Address(Rthread, JavaThread::last_Java_sp_offset()));
reset_last_Java_frame(tmp);
// C++ interp handles this in the interpreter
check_and_handle_popframe();
check_and_handle_earlyret();
if (check_exceptions) {
// check for pending exceptions
ldr(tmp, Address(Rthread, Thread::pending_exception_offset()));
cmp(tmp, 0);
mov(Rexception_pc, PC, ne);
b(StubRoutines::forward_exception_entry(), ne);
}
// get oop result if there is one and reset the value in the thread
if (oop_result->is_valid()) {
get_vm_result(oop_result, tmp);
}
}
void MacroAssembler::call_VM(Register oop_result, address entry_point, bool check_exceptions) {
call_VM_helper(oop_result, entry_point, 0, check_exceptions);
}
void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1, bool check_exceptions) {
assert (arg_1 == R1, "fixed register for arg_1");
call_VM_helper(oop_result, entry_point, 1, check_exceptions);
}
void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1, Register arg_2, bool check_exceptions) {
assert (arg_1 == R1, "fixed register for arg_1");
assert (arg_2 == R2, "fixed register for arg_2");
call_VM_helper(oop_result, entry_point, 2, check_exceptions);
}
void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1, Register arg_2, Register arg_3, bool check_exceptions) {
assert (arg_1 == R1, "fixed register for arg_1");
assert (arg_2 == R2, "fixed register for arg_2");
assert (arg_3 == R3, "fixed register for arg_3");
call_VM_helper(oop_result, entry_point, 3, check_exceptions);
}
void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, int number_of_arguments, bool check_exceptions) {
// Not used on ARM
Unimplemented();
}
void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, Register arg_1, bool check_exceptions) {
// Not used on ARM
Unimplemented();
}
void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, Register arg_1, Register arg_2, bool check_exceptions) {
// Not used on ARM
Unimplemented();
}
void MacroAssembler::call_VM(Register oop_result, Register last_java_sp, address entry_point, Register arg_1, Register arg_2, Register arg_3, bool check_exceptions) {
// Not used on ARM
Unimplemented();
}
// Raw call, without saving/restoring registers, exception handling, etc.
// Mainly used from various stubs.
void MacroAssembler::call_VM(address entry_point, bool save_R9_if_scratched) {
const Register tmp = Rtemp; // Rtemp free since scratched by call
set_last_Java_frame(SP, FP, true, tmp);
#if R9_IS_SCRATCHED
if (save_R9_if_scratched) {
// Note: Saving also R10 for alignment.
push(RegisterSet(R9, R10));
}
#endif
mov(R0, Rthread);
call(entry_point, relocInfo::runtime_call_type);
#if R9_IS_SCRATCHED
if (save_R9_if_scratched) {
pop(RegisterSet(R9, R10));
}
#endif
reset_last_Java_frame(tmp);
}
void MacroAssembler::call_VM_leaf(address entry_point) {
call_VM_leaf_helper(entry_point, 0);
}
void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1) {
assert (arg_1 == R0, "fixed register for arg_1");
call_VM_leaf_helper(entry_point, 1);
}
void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1, Register arg_2) {
assert (arg_1 == R0, "fixed register for arg_1");
assert (arg_2 == R1, "fixed register for arg_2");
call_VM_leaf_helper(entry_point, 2);
}
void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1, Register arg_2, Register arg_3) {
assert (arg_1 == R0, "fixed register for arg_1");
assert (arg_2 == R1, "fixed register for arg_2");
assert (arg_3 == R2, "fixed register for arg_3");
call_VM_leaf_helper(entry_point, 3);
}
void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1, Register arg_2, Register arg_3, Register arg_4) {
assert (arg_1 == R0, "fixed register for arg_1");
assert (arg_2 == R1, "fixed register for arg_2");
assert (arg_3 == R2, "fixed register for arg_3");
assert (arg_4 == R3, "fixed register for arg_4");
call_VM_leaf_helper(entry_point, 4);
}
void MacroAssembler::get_vm_result(Register oop_result, Register tmp) {
assert_different_registers(oop_result, tmp);
ldr(oop_result, Address(Rthread, JavaThread::vm_result_offset()));
str(zero_register(tmp), Address(Rthread, JavaThread::vm_result_offset()));
verify_oop(oop_result);
}
void MacroAssembler::get_vm_result_2(Register metadata_result, Register tmp) {
assert_different_registers(metadata_result, tmp);
ldr(metadata_result, Address(Rthread, JavaThread::vm_result_2_offset()));
str(zero_register(tmp), Address(Rthread, JavaThread::vm_result_2_offset()));
}
void MacroAssembler::add_rc(Register dst, Register arg1, RegisterOrConstant arg2) {
if (arg2.is_register()) {
add(dst, arg1, arg2.as_register());
} else {
add(dst, arg1, arg2.as_constant());
}
}
void MacroAssembler::add_slow(Register rd, Register rn, int c) {
// This function is used in compiler for handling large frame offsets
if ((c < 0) && (((-c) & ~0x3fc) == 0)) {
return sub(rd, rn, (-c));
}
int low = c & 0x3fc;
if (low != 0) {
add(rd, rn, low);
rn = rd;
}
if (c & ~0x3fc) {
assert(AsmOperand::is_rotated_imm(c & ~0x3fc), "unsupported add_slow offset %d", c);
add(rd, rn, c & ~0x3fc);
} else if (rd != rn) {
assert(c == 0, "");
mov(rd, rn); // need to generate at least one move!
}
}
void MacroAssembler::sub_slow(Register rd, Register rn, int c) {
// This function is used in compiler for handling large frame offsets
if ((c < 0) && (((-c) & ~0x3fc) == 0)) {
return add(rd, rn, (-c));
}
int low = c & 0x3fc;
if (low != 0) {
sub(rd, rn, low);
rn = rd;
}
if (c & ~0x3fc) {
assert(AsmOperand::is_rotated_imm(c & ~0x3fc), "unsupported sub_slow offset %d", c);
sub(rd, rn, c & ~0x3fc);
} else if (rd != rn) {
assert(c == 0, "");
mov(rd, rn); // need to generate at least one move!
}
}
void MacroAssembler::mov_slow(Register rd, address addr) {
// do *not* call the non relocated mov_related_address
mov_slow(rd, (intptr_t)addr);
}
void MacroAssembler::mov_slow(Register rd, const char *str) {
mov_slow(rd, (intptr_t)str);
}
void MacroAssembler::mov_slow(Register rd, intptr_t c, AsmCondition cond) {
if (AsmOperand::is_rotated_imm(c)) {
mov(rd, c, cond);
} else if (AsmOperand::is_rotated_imm(~c)) {
mvn(rd, ~c, cond);
} else if (VM_Version::supports_movw()) {
movw(rd, c & 0xffff, cond);
if ((unsigned int)c >> 16) {
movt(rd, (unsigned int)c >> 16, cond);
}
} else {
// Find first non-zero bit
int shift = 0;
while ((c & (3 << shift)) == 0) {
shift += 2;
}
// Put the least significant part of the constant
int mask = 0xff << shift;
mov(rd, c & mask, cond);
// Add up to 3 other parts of the constant;
// each of them can be represented as rotated_imm
if (c & (mask << 8)) {
orr(rd, rd, c & (mask << 8), cond);
}
if (c & (mask << 16)) {
orr(rd, rd, c & (mask << 16), cond);
}
if (c & (mask << 24)) {
orr(rd, rd, c & (mask << 24), cond);
}
}
}
void MacroAssembler::mov_oop(Register rd, jobject o, int oop_index,
AsmCondition cond
) {
if (o == NULL) {
mov(rd, 0, cond);
return;
}
if (oop_index == 0) {
oop_index = oop_recorder()->allocate_oop_index(o);
}
relocate(oop_Relocation::spec(oop_index));
if (VM_Version::supports_movw()) {
movw(rd, 0, cond);
movt(rd, 0, cond);
} else {
ldr(rd, Address(PC), cond);
// Extra nop to handle case of large offset of oop placeholder (see NativeMovConstReg::set_data).
nop();
}
}
void MacroAssembler::mov_metadata(Register rd, Metadata* o, int metadata_index) {
if (o == NULL) {
mov(rd, 0);
return;
}
if (metadata_index == 0) {
metadata_index = oop_recorder()->allocate_metadata_index(o);
}
relocate(metadata_Relocation::spec(metadata_index));
if (VM_Version::supports_movw()) {
movw(rd, ((int)o) & 0xffff);
movt(rd, (unsigned int)o >> 16);
} else {
ldr(rd, Address(PC));
// Extra nop to handle case of large offset of metadata placeholder (see NativeMovConstReg::set_data).
nop();
}
}
void MacroAssembler::mov_float(FloatRegister fd, jfloat c, AsmCondition cond) {
Label skip_constant;
union {
jfloat f;
jint i;
} accessor;
accessor.f = c;
flds(fd, Address(PC), cond);
b(skip_constant);
emit_int32(accessor.i);
bind(skip_constant);
}
void MacroAssembler::mov_double(FloatRegister fd, jdouble c, AsmCondition cond) {
Label skip_constant;
union {
jdouble d;
jint i[2];
} accessor;
accessor.d = c;
fldd(fd, Address(PC), cond);
b(skip_constant);
emit_int32(accessor.i[0]);
emit_int32(accessor.i[1]);
bind(skip_constant);
}
void MacroAssembler::ldr_global_s32(Register reg, address address_of_global) {
intptr_t addr = (intptr_t) address_of_global;
mov_slow(reg, addr & ~0xfff);
ldr(reg, Address(reg, addr & 0xfff));
}
void MacroAssembler::ldr_global_ptr(Register reg, address address_of_global) {
ldr_global_s32(reg, address_of_global);
}
void MacroAssembler::ldrb_global(Register reg, address address_of_global) {
intptr_t addr = (intptr_t) address_of_global;
mov_slow(reg, addr & ~0xfff);
ldrb(reg, Address(reg, addr & 0xfff));
}
void MacroAssembler::zero_extend(Register rd, Register rn, int bits) {
if (bits <= 8) {
andr(rd, rn, (1 << bits) - 1);
} else if (bits >= 24) {
bic(rd, rn, -1 << bits);
} else {
mov(rd, AsmOperand(rn, lsl, 32 - bits));
mov(rd, AsmOperand(rd, lsr, 32 - bits));
}
}
void MacroAssembler::sign_extend(Register rd, Register rn, int bits) {
mov(rd, AsmOperand(rn, lsl, 32 - bits));
mov(rd, AsmOperand(rd, asr, 32 - bits));
}
void MacroAssembler::cmpoop(Register obj1, Register obj2) {
BarrierSetAssembler* bs = BarrierSet::barrier_set()->barrier_set_assembler();
bs->obj_equals(this, obj1, obj2);
}
void MacroAssembler::long_move(Register rd_lo, Register rd_hi,
Register rn_lo, Register rn_hi,
AsmCondition cond) {
if (rd_lo != rn_hi) {
if (rd_lo != rn_lo) { mov(rd_lo, rn_lo, cond); }
if (rd_hi != rn_hi) { mov(rd_hi, rn_hi, cond); }
} else if (rd_hi != rn_lo) {
if (rd_hi != rn_hi) { mov(rd_hi, rn_hi, cond); }
if (rd_lo != rn_lo) { mov(rd_lo, rn_lo, cond); }
} else {
eor(rd_lo, rd_hi, rd_lo, cond);
eor(rd_hi, rd_lo, rd_hi, cond);
eor(rd_lo, rd_hi, rd_lo, cond);
}
}
void MacroAssembler::long_shift(Register rd_lo, Register rd_hi,
Register rn_lo, Register rn_hi,
AsmShift shift, Register count) {
Register tmp;
if (rd_lo != rn_lo && rd_lo != rn_hi && rd_lo != count) {
tmp = rd_lo;
} else {
tmp = rd_hi;
}
assert_different_registers(tmp, count, rn_lo, rn_hi);
subs(tmp, count, 32);
if (shift == lsl) {
assert_different_registers(rd_hi, rn_lo);
assert_different_registers(count, rd_hi);
mov(rd_hi, AsmOperand(rn_lo, shift, tmp), pl);
rsb(tmp, count, 32, mi);
if (rd_hi == rn_hi) {
mov(rd_hi, AsmOperand(rn_hi, lsl, count), mi);
orr(rd_hi, rd_hi, AsmOperand(rn_lo, lsr, tmp), mi);
} else {
mov(rd_hi, AsmOperand(rn_lo, lsr, tmp), mi);
orr(rd_hi, rd_hi, AsmOperand(rn_hi, lsl, count), mi);
}
mov(rd_lo, AsmOperand(rn_lo, shift, count));
} else {
assert_different_registers(rd_lo, rn_hi);
assert_different_registers(rd_lo, count);
mov(rd_lo, AsmOperand(rn_hi, shift, tmp), pl);
rsb(tmp, count, 32, mi);
if (rd_lo == rn_lo) {
mov(rd_lo, AsmOperand(rn_lo, lsr, count), mi);
orr(rd_lo, rd_lo, AsmOperand(rn_hi, lsl, tmp), mi);
} else {
mov(rd_lo, AsmOperand(rn_hi, lsl, tmp), mi);
orr(rd_lo, rd_lo, AsmOperand(rn_lo, lsr, count), mi);
}
mov(rd_hi, AsmOperand(rn_hi, shift, count));
}
}
void MacroAssembler::long_shift(Register rd_lo, Register rd_hi,
Register rn_lo, Register rn_hi,
AsmShift shift, int count) {
assert(count != 0 && (count & ~63) == 0, "must be");
if (shift == lsl) {
assert_different_registers(rd_hi, rn_lo);
if (count >= 32) {
mov(rd_hi, AsmOperand(rn_lo, lsl, count - 32));
mov(rd_lo, 0);
} else {
mov(rd_hi, AsmOperand(rn_hi, lsl, count));
orr(rd_hi, rd_hi, AsmOperand(rn_lo, lsr, 32 - count));
mov(rd_lo, AsmOperand(rn_lo, lsl, count));
}
} else {
assert_different_registers(rd_lo, rn_hi);
if (count >= 32) {
if (count == 32) {
mov(rd_lo, rn_hi);
} else {
mov(rd_lo, AsmOperand(rn_hi, shift, count - 32));
}
if (shift == asr) {
mov(rd_hi, AsmOperand(rn_hi, asr, 0));
} else {
mov(rd_hi, 0);
}
} else {
mov(rd_lo, AsmOperand(rn_lo, lsr, count));
orr(rd_lo, rd_lo, AsmOperand(rn_hi, lsl, 32 - count));
mov(rd_hi, AsmOperand(rn_hi, shift, count));
}
}
}
void MacroAssembler::_verify_oop(Register reg, const char* s, const char* file, int line) {
// This code pattern is matched in NativeIntruction::skip_verify_oop.
// Update it at modifications.
if (!VerifyOops) return;
char buffer[64];
#ifdef COMPILER1
if (CommentedAssembly) {
snprintf(buffer, sizeof(buffer), "verify_oop at %d", offset());
block_comment(buffer);
}
#endif
const char* msg_buffer = NULL;
{
ResourceMark rm;
stringStream ss;
ss.print("%s at offset %d (%s:%d)", s, offset(), file, line);
msg_buffer = code_string(ss.as_string());
}
save_all_registers();
if (reg != R2) {
mov(R2, reg); // oop to verify
}
mov(R1, SP); // register save area
Label done;
InlinedString Lmsg(msg_buffer);
ldr_literal(R0, Lmsg); // message
// call indirectly to solve generation ordering problem
ldr_global_ptr(Rtemp, StubRoutines::verify_oop_subroutine_entry_address());
call(Rtemp);
restore_all_registers();
b(done);
#ifdef COMPILER2
int off = offset();
#endif
bind_literal(Lmsg);
#ifdef COMPILER2
if (offset() - off == 1 * wordSize) {
// no padding, so insert nop for worst-case sizing
nop();
}
#endif
bind(done);
}
void MacroAssembler::_verify_oop_addr(Address addr, const char* s, const char* file, int line) {
if (!VerifyOops) return;
const char* msg_buffer = NULL;
{
ResourceMark rm;
stringStream ss;
if ((addr.base() == SP) && (addr.index()==noreg)) {
ss.print("verify_oop_addr SP[%d]: %s", (int)addr.disp(), s);
} else {
ss.print("verify_oop_addr: %s", s);
}
ss.print(" (%s:%d)", file, line);
msg_buffer = code_string(ss.as_string());
}
int push_size = save_all_registers();
if (addr.base() == SP) {
// computes an addr that takes into account the push
if (addr.index() != noreg) {
Register new_base = addr.index() == R2 ? R1 : R2; // avoid corrupting the index
add(new_base, SP, push_size);
addr = addr.rebase(new_base);
} else {
addr = addr.plus_disp(push_size);
}
}
ldr(R2, addr); // oop to verify
mov(R1, SP); // register save area
Label done;
InlinedString Lmsg(msg_buffer);
ldr_literal(R0, Lmsg); // message
// call indirectly to solve generation ordering problem
ldr_global_ptr(Rtemp, StubRoutines::verify_oop_subroutine_entry_address());
call(Rtemp);
restore_all_registers();
b(done);
bind_literal(Lmsg);
bind(done);
}
void MacroAssembler::c2bool(Register x)
{
tst(x, 0xff); // Only look at the lowest byte
mov(x, 1, ne);
}
void MacroAssembler::null_check(Register reg, Register tmp, int offset) {
if (needs_explicit_null_check(offset)) {
assert_different_registers(reg, tmp);
if (tmp == noreg) {
tmp = Rtemp;
assert((! Thread::current()->is_Compiler_thread()) ||
(! (ciEnv::current()->task() == NULL)) ||
(! (ciEnv::current()->comp_level() == CompLevel_full_optimization)),
"Rtemp not available in C2"); // explicit tmp register required
// XXX: could we mark the code buffer as not compatible with C2 ?
}
ldr(tmp, Address(reg));
}
}
// Puts address of allocated object into register `obj` and end of allocated object into register `obj_end`.
void MacroAssembler::eden_allocate(Register obj, Register obj_end, Register tmp1, Register tmp2,
RegisterOrConstant size_expression, Label& slow_case) {
BarrierSetAssembler *bs = BarrierSet::barrier_set()->barrier_set_assembler();
bs->eden_allocate(this, obj, obj_end, tmp1, tmp2, size_expression, slow_case);
}
// Puts address of allocated object into register `obj` and end of allocated object into register `obj_end`.
void MacroAssembler::tlab_allocate(Register obj, Register obj_end, Register tmp1,
RegisterOrConstant size_expression, Label& slow_case) {
BarrierSetAssembler *bs = BarrierSet::barrier_set()->barrier_set_assembler();
bs->tlab_allocate(this, obj, obj_end, tmp1, size_expression, slow_case);
}
// Fills memory regions [start..end] with zeroes. Clobbers `start` and `tmp` registers.
void MacroAssembler::zero_memory(Register start, Register end, Register tmp) {
Label loop;
const Register ptr = start;
mov(tmp, 0);
bind(loop);
cmp(ptr, end);
str(tmp, Address(ptr, wordSize, post_indexed), lo);
b(loop, lo);
}
void MacroAssembler::arm_stack_overflow_check(int frame_size_in_bytes, Register tmp) {
// Version of AbstractAssembler::generate_stack_overflow_check optimized for ARM
if (UseStackBanging) {
const int page_size = os::vm_page_size();
sub_slow(tmp, SP, JavaThread::stack_shadow_zone_size());
strb(R0, Address(tmp));
for (; frame_size_in_bytes >= page_size; frame_size_in_bytes -= 0xff0) {
strb(R0, Address(tmp, -0xff0, pre_indexed));
}
}
}
void MacroAssembler::arm_stack_overflow_check(Register Rsize, Register tmp) {
if (UseStackBanging) {
Label loop;
mov(tmp, SP);
add_slow(Rsize, Rsize, JavaThread::stack_shadow_zone_size() - os::vm_page_size());
bind(loop);
subs(Rsize, Rsize, 0xff0);
strb(R0, Address(tmp, -0xff0, pre_indexed));
b(loop, hi);
}
}
void MacroAssembler::stop(const char* msg) {
// This code pattern is matched in NativeIntruction::is_stop.
// Update it at modifications.
#ifdef COMPILER1
if (CommentedAssembly) {
block_comment("stop");
}
#endif
InlinedAddress Ldebug(CAST_FROM_FN_PTR(address, MacroAssembler::debug));
InlinedString Lmsg(msg);
// save all registers for further inspection
save_all_registers();
ldr_literal(R0, Lmsg); // message
mov(R1, SP); // register save area
ldr_literal(PC, Ldebug); // call MacroAssembler::debug
bind_literal(Lmsg);
bind_literal(Ldebug);
}
void MacroAssembler::warn(const char* msg) {
#ifdef COMPILER1
if (CommentedAssembly) {
block_comment("warn");
}
#endif
InlinedAddress Lwarn(CAST_FROM_FN_PTR(address, warning));
InlinedString Lmsg(msg);
Label done;
int push_size = save_caller_save_registers();
ldr_literal(R0, Lmsg); // message
ldr_literal(LR, Lwarn); // call warning
call(LR);
restore_caller_save_registers();
b(done);
bind_literal(Lmsg);
bind_literal(Lwarn);
bind(done);
}
int MacroAssembler::save_all_registers() {
// This code pattern is matched in NativeIntruction::is_save_all_registers.
// Update it at modifications.
push(RegisterSet(R0, R12) | RegisterSet(LR) | RegisterSet(PC));
return 15*wordSize;
}
void MacroAssembler::restore_all_registers() {
pop(RegisterSet(R0, R12) | RegisterSet(LR)); // restore registers
add(SP, SP, wordSize); // discard saved PC
}
int MacroAssembler::save_caller_save_registers() {
#if R9_IS_SCRATCHED
// Save also R10 to preserve alignment
push(RegisterSet(R0, R3) | RegisterSet(R12) | RegisterSet(LR) | RegisterSet(R9,R10));
return 8*wordSize;
#else
push(RegisterSet(R0, R3) | RegisterSet(R12) | RegisterSet(LR));
return 6*wordSize;
#endif
}
void MacroAssembler::restore_caller_save_registers() {
#if R9_IS_SCRATCHED
pop(RegisterSet(R0, R3) | RegisterSet(R12) | RegisterSet(LR) | RegisterSet(R9,R10));
#else
pop(RegisterSet(R0, R3) | RegisterSet(R12) | RegisterSet(LR));
#endif
}
void MacroAssembler::debug(const char* msg, const intx* registers) {
// In order to get locks to work, we need to fake a in_VM state
JavaThread* thread = JavaThread::current();
thread->set_thread_state(_thread_in_vm);
if (ShowMessageBoxOnError) {
ttyLocker ttyl;
if (CountBytecodes || TraceBytecodes || StopInterpreterAt) {
BytecodeCounter::print();
}
if (os::message_box(msg, "Execution stopped, print registers?")) {
// saved registers: R0-R12, LR, PC
const int nregs = 15;
const Register regs[nregs] = {R0, R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, LR, PC};
for (int i = 0; i < nregs; i++) {
tty->print_cr("%s = " INTPTR_FORMAT, regs[i]->name(), registers[i]);
}
// derive original SP value from the address of register save area
tty->print_cr("%s = " INTPTR_FORMAT, SP->name(), p2i(®isters[nregs]));
}
BREAKPOINT;
} else {
::tty->print_cr("=============== DEBUG MESSAGE: %s ================\n", msg);
}
assert(false, "DEBUG MESSAGE: %s", msg);
fatal("%s", msg); // returning from MacroAssembler::debug is not supported
}
void MacroAssembler::unimplemented(const char* what) {
const char* buf = NULL;
{
ResourceMark rm;
stringStream ss;
ss.print("unimplemented: %s", what);
buf = code_string(ss.as_string());
}
stop(buf);
}
// Implementation of FixedSizeCodeBlock
FixedSizeCodeBlock::FixedSizeCodeBlock(MacroAssembler* masm, int size_in_instrs, bool enabled) :
_masm(masm), _start(masm->pc()), _size_in_instrs(size_in_instrs), _enabled(enabled) {
}
FixedSizeCodeBlock::~FixedSizeCodeBlock() {
if (_enabled) {
address curr_pc = _masm->pc();
assert(_start < curr_pc, "invalid current pc");
guarantee(curr_pc <= _start + _size_in_instrs * Assembler::InstructionSize, "code block is too long");
int nops_count = (_start - curr_pc) / Assembler::InstructionSize + _size_in_instrs;
for (int i = 0; i < nops_count; i++) {
_masm->nop();
}
}
}
// Serializes memory. Potentially blows flags and reg.
// tmp is a scratch for v6 co-processor write op (could be noreg for other architecure versions)
// preserve_flags takes a longer path in LoadStore case (dmb rather then control dependency) to preserve status flags. Optional.
// load_tgt is an ordered load target in a LoadStore case only, to create dependency between the load operation and conditional branch. Optional.
void MacroAssembler::membar(Membar_mask_bits order_constraint,
Register tmp,
bool preserve_flags,
Register load_tgt) {
if (order_constraint == StoreStore) {
dmb(DMB_st, tmp);
} else if ((order_constraint & StoreLoad) ||
(order_constraint & LoadLoad) ||
(order_constraint & StoreStore) ||
(load_tgt == noreg) ||
preserve_flags) {
dmb(DMB_all, tmp);
} else {
// LoadStore: speculative stores reordeing is prohibited
// By providing an ordered load target register, we avoid an extra memory load reference
Label not_taken;
bind(not_taken);
cmp(load_tgt, load_tgt);
b(not_taken, ne);
}
}
// If "allow_fallthrough_on_failure" is false, we always branch to "slow_case"
// on failure, so fall-through can only mean success.
// "one_shot" controls whether we loop and retry to mitigate spurious failures.
// This is only needed for C2, which for some reason does not rety,
// while C1/interpreter does.
// TODO: measure if it makes a difference
void MacroAssembler::cas_for_lock_acquire(Register oldval, Register newval,
Register base, Register tmp, Label &slow_case,
bool allow_fallthrough_on_failure, bool one_shot)
{
bool fallthrough_is_success = false;
// ARM Litmus Test example does prefetching here.
// TODO: investigate if it helps performance
// The last store was to the displaced header, so to prevent
// reordering we must issue a StoreStore or Release barrier before
// the CAS store.
membar(MacroAssembler::StoreStore, noreg);
if (one_shot) {
ldrex(tmp, Address(base, oopDesc::mark_offset_in_bytes()));
cmp(tmp, oldval);
strex(tmp, newval, Address(base, oopDesc::mark_offset_in_bytes()), eq);
cmp(tmp, 0, eq);
} else {
atomic_cas_bool(oldval, newval, base, oopDesc::mark_offset_in_bytes(), tmp);
}
// MemBarAcquireLock barrier
// According to JSR-133 Cookbook, this should be LoadLoad | LoadStore,
// but that doesn't prevent a load or store from floating up between
// the load and store in the CAS sequence, so play it safe and
// do a full fence.
membar(Membar_mask_bits(LoadLoad | LoadStore | StoreStore | StoreLoad), noreg);
if (!fallthrough_is_success && !allow_fallthrough_on_failure) {
b(slow_case, ne);
}
}
void MacroAssembler::cas_for_lock_release(Register oldval, Register newval,
Register base, Register tmp, Label &slow_case,
bool allow_fallthrough_on_failure, bool one_shot)
{
bool fallthrough_is_success = false;
assert_different_registers(oldval,newval,base,tmp);
// MemBarReleaseLock barrier
// According to JSR-133 Cookbook, this should be StoreStore | LoadStore,
// but that doesn't prevent a load or store from floating down between
// the load and store in the CAS sequence, so play it safe and
// do a full fence.
membar(Membar_mask_bits(LoadLoad | LoadStore | StoreStore | StoreLoad), tmp);
if (one_shot) {
ldrex(tmp, Address(base, oopDesc::mark_offset_in_bytes()));
cmp(tmp, oldval);
strex(tmp, newval, Address(base, oopDesc::mark_offset_in_bytes()), eq);
cmp(tmp, 0, eq);
} else {
atomic_cas_bool(oldval, newval, base, oopDesc::mark_offset_in_bytes(), tmp);
}
if (!fallthrough_is_success && !allow_fallthrough_on_failure) {
b(slow_case, ne);
}
// ExitEnter
// According to JSR-133 Cookbook, this should be StoreLoad, the same
// barrier that follows volatile store.
// TODO: Should be able to remove on armv8 if volatile loads
// use the load-acquire instruction.
membar(StoreLoad, noreg);
}
#ifndef PRODUCT
// Preserves flags and all registers.
// On SMP the updated value might not be visible to external observers without a sychronization barrier
void MacroAssembler::cond_atomic_inc32(AsmCondition cond, int* counter_addr) {
if (counter_addr != NULL) {
InlinedAddress counter_addr_literal((address)counter_addr);
Label done, retry;
if (cond != al) {
b(done, inverse(cond));
}
push(RegisterSet(R0, R3) | RegisterSet(Rtemp));
ldr_literal(R0, counter_addr_literal);
mrs(CPSR, Rtemp);
bind(retry);
ldr_s32(R1, Address(R0));
add(R2, R1, 1);
atomic_cas_bool(R1, R2, R0, 0, R3);
b(retry, ne);
msr(CPSR_fsxc, Rtemp);
pop(RegisterSet(R0, R3) | RegisterSet(Rtemp));
b(done);
bind_literal(counter_addr_literal);
bind(done);
}
}
#endif // !PRODUCT
// Building block for CAS cases of biased locking: makes CAS and records statistics.
// The slow_case label is used to transfer control if CAS fails. Otherwise leaves condition codes set.
void MacroAssembler::biased_locking_enter_with_cas(Register obj_reg, Register old_mark_reg, Register new_mark_reg,
Register tmp, Label& slow_case, int* counter_addr) {
cas_for_lock_acquire(old_mark_reg, new_mark_reg, obj_reg, tmp, slow_case);
#ifdef ASSERT
breakpoint(ne); // Fallthrough only on success
#endif
#ifndef PRODUCT
if (counter_addr != NULL) {
cond_atomic_inc32(al, counter_addr);
}
#endif // !PRODUCT
}
int MacroAssembler::biased_locking_enter(Register obj_reg, Register swap_reg, Register tmp_reg,
bool swap_reg_contains_mark,
Register tmp2,
Label& done, Label& slow_case,
BiasedLockingCounters* counters) {
// obj_reg must be preserved (at least) if the bias locking fails
// tmp_reg is a temporary register
// swap_reg was used as a temporary but contained a value
// that was used afterwards in some call pathes. Callers
// have been fixed so that swap_reg no longer needs to be
// saved.
// Rtemp in no longer scratched
assert(UseBiasedLocking, "why call this otherwise?");
assert_different_registers(obj_reg, swap_reg, tmp_reg, tmp2);
guarantee(swap_reg!=tmp_reg, "invariant");
assert(tmp_reg != noreg, "must supply tmp_reg");
#ifndef PRODUCT
if (PrintBiasedLockingStatistics && (counters == NULL)) {
counters = BiasedLocking::counters();
}
#endif
assert(markWord::age_shift == markWord::lock_bits + markWord::biased_lock_bits, "biased locking makes assumptions about bit layout");
Address mark_addr(obj_reg, oopDesc::mark_offset_in_bytes());
// Biased locking
// See whether the lock is currently biased toward our thread and
// whether the epoch is still valid
// Note that the runtime guarantees sufficient alignment of JavaThread
// pointers to allow age to be placed into low bits
// First check to see whether biasing is even enabled for this object
Label cas_label;
// The null check applies to the mark loading, if we need to load it.
// If the mark has already been loaded in swap_reg then it has already
// been performed and the offset is irrelevant.
int null_check_offset = offset();
if (!swap_reg_contains_mark) {
ldr(swap_reg, mark_addr);
}
// On MP platform loads could return 'stale' values in some cases.
// That is acceptable since either CAS or slow case path is taken in the worst case.
andr(tmp_reg, swap_reg, markWord::biased_lock_mask_in_place);
cmp(tmp_reg, markWord::biased_lock_pattern);
b(cas_label, ne);
// The bias pattern is present in the object's header. Need to check
// whether the bias owner and the epoch are both still current.
load_klass(tmp_reg, obj_reg);
ldr(tmp_reg, Address(tmp_reg, Klass::prototype_header_offset()));
orr(tmp_reg, tmp_reg, Rthread);
eor(tmp_reg, tmp_reg, swap_reg);
bics(tmp_reg, tmp_reg, ((int) markWord::age_mask_in_place));
#ifndef PRODUCT
if (counters != NULL) {
cond_atomic_inc32(eq, counters->biased_lock_entry_count_addr());
}
#endif // !PRODUCT
b(done, eq);
Label try_revoke_bias;
Label try_rebias;
// At this point we know that the header has the bias pattern and
// that we are not the bias owner in the current epoch. We need to
// figure out more details about the state of the header in order to
// know what operations can be legally performed on the object's
// header.
// If the low three bits in the xor result aren't clear, that means
// the prototype header is no longer biased and we have to revoke
// the bias on this object.
tst(tmp_reg, markWord::biased_lock_mask_in_place);
b(try_revoke_bias, ne);
// Biasing is still enabled for this data type. See whether the
// epoch of the current bias is still valid, meaning that the epoch
// bits of the mark word are equal to the epoch bits of the
// prototype header. (Note that the prototype header's epoch bits
// only change at a safepoint.) If not, attempt to rebias the object
// toward the current thread. Note that we must be absolutely sure
// that the current epoch is invalid in order to do this because
// otherwise the manipulations it performs on the mark word are
// illegal.
tst(tmp_reg, markWord::epoch_mask_in_place);
b(try_rebias, ne);
// tmp_reg has the age, epoch and pattern bits cleared
// The remaining (owner) bits are (Thread ^ current_owner)
// The epoch of the current bias is still valid but we know nothing
// about the owner; it might be set or it might be clear. Try to
// acquire the bias of the object using an atomic operation. If this
// fails we will go in to the runtime to revoke the object's bias.
// Note that we first construct the presumed unbiased header so we
// don't accidentally blow away another thread's valid bias.
// Note that we know the owner is not ourself. Hence, success can
// only happen when the owner bits is 0
// until the assembler can be made smarter, we need to make some assumptions about the values
// so we can optimize this:
assert((markWord::biased_lock_mask_in_place | markWord::age_mask_in_place | markWord::epoch_mask_in_place) == 0x1ff, "biased bitmasks changed");
mov(swap_reg, AsmOperand(swap_reg, lsl, 23));
mov(swap_reg, AsmOperand(swap_reg, lsr, 23)); // markWord with thread bits cleared (for CAS)
orr(tmp_reg, swap_reg, Rthread); // new mark
biased_locking_enter_with_cas(obj_reg, swap_reg, tmp_reg, tmp2, slow_case,
(counters != NULL) ? counters->anonymously_biased_lock_entry_count_addr() : NULL);
// If the biasing toward our thread failed, this means that
// another thread succeeded in biasing it toward itself and we
// need to revoke that bias. The revocation will occur in the
// interpreter runtime in the slow case.
b(done);
bind(try_rebias);
// At this point we know the epoch has expired, meaning that the
// current "bias owner", if any, is actually invalid. Under these
// circumstances _only_, we are allowed to use the current header's
// value as the comparison value when doing the cas to acquire the
// bias in the current epoch. In other words, we allow transfer of
// the bias from one thread to another directly in this situation.
// tmp_reg low (not owner) bits are (age: 0 | pattern&epoch: prototype^swap_reg)
eor(tmp_reg, tmp_reg, swap_reg); // OK except for owner bits (age preserved !)
// owner bits 'random'. Set them to Rthread.
mov(tmp_reg, AsmOperand(tmp_reg, lsl, 23));
mov(tmp_reg, AsmOperand(tmp_reg, lsr, 23));
orr(tmp_reg, tmp_reg, Rthread); // new mark
biased_locking_enter_with_cas(obj_reg, swap_reg, tmp_reg, tmp2, slow_case,
(counters != NULL) ? counters->rebiased_lock_entry_count_addr() : NULL);
// If the biasing toward our thread failed, then another thread
// succeeded in biasing it toward itself and we need to revoke that
// bias. The revocation will occur in the runtime in the slow case.
b(done);
bind(try_revoke_bias);
// The prototype mark in the klass doesn't have the bias bit set any
// more, indicating that objects of this data type are not supposed
// to be biased any more. We are going to try to reset the mark of
// this object to the prototype value and fall through to the
// CAS-based locking scheme. Note that if our CAS fails, it means
// that another thread raced us for the privilege of revoking the
// bias of this particular object, so it's okay to continue in the
// normal locking code.
// tmp_reg low (not owner) bits are (age: 0 | pattern&epoch: prototype^swap_reg)
eor(tmp_reg, tmp_reg, swap_reg); // OK except for owner bits (age preserved !)
// owner bits 'random'. Clear them
mov(tmp_reg, AsmOperand(tmp_reg, lsl, 23));
mov(tmp_reg, AsmOperand(tmp_reg, lsr, 23));
biased_locking_enter_with_cas(obj_reg, swap_reg, tmp_reg, tmp2, cas_label,
(counters != NULL) ? counters->revoked_lock_entry_count_addr() : NULL);
// Fall through to the normal CAS-based lock, because no matter what
// the result of the above CAS, some thread must have succeeded in
// removing the bias bit from the object's header.
bind(cas_label);
return null_check_offset;
}
void MacroAssembler::biased_locking_exit(Register obj_reg, Register tmp_reg, Label& done) {
assert(UseBiasedLocking, "why call this otherwise?");
// Check for biased locking unlock case, which is a no-op
// Note: we do not have to check the thread ID for two reasons.
// First, the interpreter checks for IllegalMonitorStateException at
// a higher level. Second, if the bias was revoked while we held the
// lock, the object could not be rebiased toward another thread, so
// the bias bit would be clear.
ldr(tmp_reg, Address(obj_reg, oopDesc::mark_offset_in_bytes()));
andr(tmp_reg, tmp_reg, markWord::biased_lock_mask_in_place);
cmp(tmp_reg, markWord::biased_lock_pattern);
b(done, eq);
}
void MacroAssembler::resolve_jobject(Register value,
Register tmp1,
Register tmp2) {
assert_different_registers(value, tmp1, tmp2);
Label done, not_weak;
cbz(value, done); // Use NULL as-is.
STATIC_ASSERT(JNIHandles::weak_tag_mask == 1u);
tbz(value, 0, not_weak); // Test for jweak tag.
// Resolve jweak.
access_load_at(T_OBJECT, IN_NATIVE | ON_PHANTOM_OOP_REF,
Address(value, -JNIHandles::weak_tag_value), value, tmp1, tmp2, noreg);
b(done);
bind(not_weak);
// Resolve (untagged) jobject.
access_load_at(T_OBJECT, IN_NATIVE,
Address(value, 0), value, tmp1, tmp2, noreg);
verify_oop(value);
bind(done);
}
//////////////////////////////////////////////////////////////////////////////////
void MacroAssembler::load_sized_value(Register dst, Address src,
size_t size_in_bytes, bool is_signed, AsmCondition cond) {
switch (size_in_bytes) {
case 4: ldr(dst, src, cond); break;
case 2: is_signed ? ldrsh(dst, src, cond) : ldrh(dst, src, cond); break;
case 1: is_signed ? ldrsb(dst, src, cond) : ldrb(dst, src, cond); break;
default: ShouldNotReachHere();
}
}
void MacroAssembler::store_sized_value(Register src, Address dst, size_t size_in_bytes, AsmCondition cond) {
switch (size_in_bytes) {
case 4: str(src, dst, cond); break;
case 2: strh(src, dst, cond); break;
case 1: strb(src, dst, cond); break;
default: ShouldNotReachHere();
}
}
// Look up the method for a megamorphic invokeinterface call.
// The target method is determined by <Rinterf, Rindex>.
// The receiver klass is in Rklass.
// On success, the result will be in method_result, and execution falls through.
// On failure, execution transfers to the given label.
void MacroAssembler::lookup_interface_method(Register Rklass,
Register Rintf,
RegisterOrConstant itable_index,
Register method_result,
Register Rscan,
Register Rtmp,
Label& L_no_such_interface) {
assert_different_registers(Rklass, Rintf, Rscan, Rtmp);
const int entry_size = itableOffsetEntry::size() * HeapWordSize;
assert(itableOffsetEntry::interface_offset_in_bytes() == 0, "not added for convenience");
// Compute start of first itableOffsetEntry (which is at the end of the vtable)
const int base = in_bytes(Klass::vtable_start_offset());
const int scale = exact_log2(vtableEntry::size_in_bytes());
ldr_s32(Rtmp, Address(Rklass, Klass::vtable_length_offset())); // Get length of vtable
add(Rscan, Rklass, base);
add(Rscan, Rscan, AsmOperand(Rtmp, lsl, scale));
// Search through the itable for an interface equal to incoming Rintf
// itable looks like [intface][offset][intface][offset][intface][offset]
Label loop;
bind(loop);
ldr(Rtmp, Address(Rscan, entry_size, post_indexed));
cmp(Rtmp, Rintf); // set ZF and CF if interface is found
cmn(Rtmp, 0, ne); // check if tmp == 0 and clear CF if it is
b(loop, ne);
// CF == 0 means we reached the end of itable without finding icklass
b(L_no_such_interface, cc);
if (method_result != noreg) {
// Interface found at previous position of Rscan, now load the method
ldr_s32(Rtmp, Address(Rscan, itableOffsetEntry::offset_offset_in_bytes() - entry_size));
if (itable_index.is_register()) {
add(Rtmp, Rtmp, Rklass); // Add offset to Klass*
assert(itableMethodEntry::size() * HeapWordSize == wordSize, "adjust the scaling in the code below");
assert(itableMethodEntry::method_offset_in_bytes() == 0, "adjust the offset in the code below");
ldr(method_result, Address::indexed_ptr(Rtmp, itable_index.as_register()));
} else {
int method_offset = itableMethodEntry::size() * HeapWordSize * itable_index.as_constant() +
itableMethodEntry::method_offset_in_bytes();
add_slow(method_result, Rklass, method_offset);
ldr(method_result, Address(method_result, Rtmp));
}
}
}
#ifdef COMPILER2
// TODO: 8 bytes at a time? pre-fetch?
// Compare char[] arrays aligned to 4 bytes.
void MacroAssembler::char_arrays_equals(Register ary1, Register ary2,
Register limit, Register result,
Register chr1, Register chr2, Label& Ldone) {
Label Lvector, Lloop;
// if (ary1 == ary2)
// return true;
cmpoop(ary1, ary2);
b(Ldone, eq);
// Note: limit contains number of bytes (2*char_elements) != 0.
tst(limit, 0x2); // trailing character ?
b(Lvector, eq);
// compare the trailing char
sub(limit, limit, sizeof(jchar));
ldrh(chr1, Address(ary1, limit));
ldrh(chr2, Address(ary2, limit));
cmp(chr1, chr2);
mov(result, 0, ne); // not equal
b(Ldone, ne);
// only one char ?
tst(limit, limit);
mov(result, 1, eq);
b(Ldone, eq);
// word by word compare, dont't need alignment check
bind(Lvector);
// Shift ary1 and ary2 to the end of the arrays, negate limit
add(ary1, limit, ary1);
add(ary2, limit, ary2);
neg(limit, limit);
bind(Lloop);
ldr_u32(chr1, Address(ary1, limit));
ldr_u32(chr2, Address(ary2, limit));
cmp_32(chr1, chr2);
mov(result, 0, ne); // not equal
b(Ldone, ne);
adds(limit, limit, 2*sizeof(jchar));
b(Lloop, ne);
// Caller should set it:
// mov(result_reg, 1); //equal
}
#endif
void MacroAssembler::inc_counter(address counter_addr, Register tmpreg1, Register tmpreg2) {
mov_slow(tmpreg1, counter_addr);
ldr_s32(tmpreg2, tmpreg1);
add_32(tmpreg2, tmpreg2, 1);
str_32(tmpreg2, tmpreg1);
}
void MacroAssembler::floating_cmp(Register dst) {
vmrs(dst, FPSCR);
orr(dst, dst, 0x08000000);
eor(dst, dst, AsmOperand(dst, lsl, 3));
mov(dst, AsmOperand(dst, asr, 30));
}
void MacroAssembler::restore_default_fp_mode() {
#ifndef __SOFTFP__
// Round to Near mode, IEEE compatible, masked exceptions
mov(Rtemp, 0);
vmsr(FPSCR, Rtemp);
#endif // !__SOFTFP__
}
// 24-bit word range == 26-bit byte range
bool check26(int offset) {
// this could be simplified, but it mimics encoding and decoding
// an actual branch insrtuction
int off1 = offset << 6 >> 8;
int encoded = off1 & ((1<<24)-1);
int decoded = encoded << 8 >> 6;
return offset == decoded;
}
// Perform some slight adjustments so the default 32MB code cache
// is fully reachable.
static inline address first_cache_address() {
return CodeCache::low_bound() + sizeof(HeapBlock::Header);
}
static inline address last_cache_address() {
return CodeCache::high_bound() - Assembler::InstructionSize;
}
// Can we reach target using unconditional branch or call from anywhere
// in the code cache (because code can be relocated)?
bool MacroAssembler::_reachable_from_cache(address target) {
#ifdef __thumb__
if ((1 & (intptr_t)target) != 0) {
// Return false to avoid 'b' if we need switching to THUMB mode.
return false;
}
#endif
address cl = first_cache_address();
address ch = last_cache_address();
if (ForceUnreachable) {
// Only addresses from CodeCache can be treated as reachable.
if (target < CodeCache::low_bound() || CodeCache::high_bound() < target) {
return false;
}
}
intptr_t loffset = (intptr_t)target - (intptr_t)cl;
intptr_t hoffset = (intptr_t)target - (intptr_t)ch;
return check26(loffset - 8) && check26(hoffset - 8);
}
bool MacroAssembler::reachable_from_cache(address target) {
assert(CodeCache::contains(pc()), "not supported");
return _reachable_from_cache(target);
}
// Can we reach the entire code cache from anywhere else in the code cache?
bool MacroAssembler::_cache_fully_reachable() {
address cl = first_cache_address();
address ch = last_cache_address();
return _reachable_from_cache(cl) && _reachable_from_cache(ch);
}
bool MacroAssembler::cache_fully_reachable() {
assert(CodeCache::contains(pc()), "not supported");
return _cache_fully_reachable();
}
void MacroAssembler::jump(address target, relocInfo::relocType rtype, Register scratch, AsmCondition cond) {
assert((rtype == relocInfo::runtime_call_type) || (rtype == relocInfo::none), "not supported");
if (reachable_from_cache(target)) {
relocate(rtype);
b(target, cond);
return;
}
// Note: relocate is not needed for the code below,
// encoding targets in absolute format.
if (ignore_non_patchable_relocations()) {
rtype = relocInfo::none;
}
if (VM_Version::supports_movw() && (scratch != noreg) && (rtype == relocInfo::none)) {
// Note: this version cannot be (atomically) patched
mov_slow(scratch, (intptr_t)target, cond);
bx(scratch, cond);
} else {
Label skip;
InlinedAddress address_literal(target);
if (cond != al) {
b(skip, inverse(cond));
}
relocate(rtype);
ldr_literal(PC, address_literal);
bind_literal(address_literal);
bind(skip);
}
}
// Similar to jump except that:
// - near calls are valid only if any destination in the cache is near
// - no movt/movw (not atomically patchable)
void MacroAssembler::patchable_jump(address target, relocInfo::relocType rtype, Register scratch, AsmCondition cond) {
assert((rtype == relocInfo::runtime_call_type) || (rtype == relocInfo::none), "not supported");
if (cache_fully_reachable()) {
// Note: this assumes that all possible targets (the initial one
// and the addressed patched to) are all in the code cache.
assert(CodeCache::contains(target), "target might be too far");
relocate(rtype);
b(target, cond);
return;
}
// Discard the relocation information if not needed for CacheCompiledCode
// since the next encodings are all in absolute format.
if (ignore_non_patchable_relocations()) {
rtype = relocInfo::none;
}
{
Label skip;
InlinedAddress address_literal(target);
if (cond != al) {
b(skip, inverse(cond));
}
relocate(rtype);
ldr_literal(PC, address_literal);
bind_literal(address_literal);
bind(skip);
}
}
void MacroAssembler::call(address target, RelocationHolder rspec, AsmCondition cond) {
Register scratch = LR;
assert(rspec.type() == relocInfo::runtime_call_type || rspec.type() == relocInfo::none, "not supported");
if (reachable_from_cache(target)) {
relocate(rspec);
bl(target, cond);
return;
}
// Note: relocate is not needed for the code below,
// encoding targets in absolute format.
if (ignore_non_patchable_relocations()) {
// This assumes the information was needed only for relocating the code.
rspec = RelocationHolder::none;
}
if (VM_Version::supports_movw() && (rspec.type() == relocInfo::none)) {
// Note: this version cannot be (atomically) patched
mov_slow(scratch, (intptr_t)target, cond);
blx(scratch, cond);
return;
}
{
Label ret_addr;
if (cond != al) {
/**代码未完, 请加载全部代码(NowJava.com).**/
关注时代Java
关注时代Java