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stubGenerator_aarch64.cpp
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stubGenerator_aarch64.cpp
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/*
* Copyright (c) 2003, 2022, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2014, 2022, Red Hat Inc. 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/macroAssembler.hpp"
#include "asm/macroAssembler.inline.hpp"
#include "asm/register.hpp"
#include "atomic_aarch64.hpp"
#include "compiler/oopMap.hpp"
#include "gc/shared/barrierSet.hpp"
#include "gc/shared/barrierSetAssembler.hpp"
#include "gc/shared/gc_globals.hpp"
#include "gc/shared/tlab_globals.hpp"
#include "interpreter/interpreter.hpp"
#include "memory/universe.hpp"
#include "nativeInst_aarch64.hpp"
#include "oops/instanceOop.hpp"
#include "oops/method.hpp"
#include "oops/objArrayKlass.hpp"
#include "oops/oop.inline.hpp"
#include "prims/methodHandles.hpp"
#include "runtime/atomic.hpp"
#include "runtime/continuation.hpp"
#include "runtime/continuationEntry.inline.hpp"
#include "runtime/frame.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubCodeGenerator.hpp"
#include "runtime/stubRoutines.hpp"
#include "utilities/align.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/powerOfTwo.hpp"
#ifdef COMPILER2
#include "opto/runtime.hpp"
#endif
#if INCLUDE_ZGC
#include "gc/z/zThreadLocalData.hpp"
#endif
// Declaration and definition of StubGenerator (no .hpp file).
// For a more detailed description of the stub routine structure
// see the comment in stubRoutines.hpp
#undef __
#define __ _masm->
#ifdef PRODUCT
#define BLOCK_COMMENT(str) /* nothing */
#else
#define BLOCK_COMMENT(str) __ block_comment(str)
#endif
#define BIND(label) bind(label); BLOCK_COMMENT(#label ":")
// Stub Code definitions
class StubGenerator: public StubCodeGenerator {
private:
#ifdef PRODUCT
#define inc_counter_np(counter) ((void)0)
#else
void inc_counter_np_(int& counter) {
__ lea(rscratch2, ExternalAddress((address)&counter));
__ ldrw(rscratch1, Address(rscratch2));
__ addw(rscratch1, rscratch1, 1);
__ strw(rscratch1, Address(rscratch2));
}
#define inc_counter_np(counter) \
BLOCK_COMMENT("inc_counter " #counter); \
inc_counter_np_(counter);
#endif
// Call stubs are used to call Java from C
//
// Arguments:
// c_rarg0: call wrapper address address
// c_rarg1: result address
// c_rarg2: result type BasicType
// c_rarg3: method Method*
// c_rarg4: (interpreter) entry point address
// c_rarg5: parameters intptr_t*
// c_rarg6: parameter size (in words) int
// c_rarg7: thread Thread*
//
// There is no return from the stub itself as any Java result
// is written to result
//
// we save r30 (lr) as the return PC at the base of the frame and
// link r29 (fp) below it as the frame pointer installing sp (r31)
// into fp.
//
// we save r0-r7, which accounts for all the c arguments.
//
// TODO: strictly do we need to save them all? they are treated as
// volatile by C so could we omit saving the ones we are going to
// place in global registers (thread? method?) or those we only use
// during setup of the Java call?
//
// we don't need to save r8 which C uses as an indirect result location
// return register.
//
// we don't need to save r9-r15 which both C and Java treat as
// volatile
//
// we don't need to save r16-18 because Java does not use them
//
// we save r19-r28 which Java uses as scratch registers and C
// expects to be callee-save
//
// we save the bottom 64 bits of each value stored in v8-v15; it is
// the responsibility of the caller to preserve larger values.
//
// so the stub frame looks like this when we enter Java code
//
// [ return_from_Java ] <--- sp
// [ argument word n ]
// ...
// -27 [ argument word 1 ]
// -26 [ saved v15 ] <--- sp_after_call
// -25 [ saved v14 ]
// -24 [ saved v13 ]
// -23 [ saved v12 ]
// -22 [ saved v11 ]
// -21 [ saved v10 ]
// -20 [ saved v9 ]
// -19 [ saved v8 ]
// -18 [ saved r28 ]
// -17 [ saved r27 ]
// -16 [ saved r26 ]
// -15 [ saved r25 ]
// -14 [ saved r24 ]
// -13 [ saved r23 ]
// -12 [ saved r22 ]
// -11 [ saved r21 ]
// -10 [ saved r20 ]
// -9 [ saved r19 ]
// -8 [ call wrapper (r0) ]
// -7 [ result (r1) ]
// -6 [ result type (r2) ]
// -5 [ method (r3) ]
// -4 [ entry point (r4) ]
// -3 [ parameters (r5) ]
// -2 [ parameter size (r6) ]
// -1 [ thread (r7) ]
// 0 [ saved fp (r29) ] <--- fp == saved sp (r31)
// 1 [ saved lr (r30) ]
// Call stub stack layout word offsets from fp
enum call_stub_layout {
sp_after_call_off = -26,
d15_off = -26,
d13_off = -24,
d11_off = -22,
d9_off = -20,
r28_off = -18,
r26_off = -16,
r24_off = -14,
r22_off = -12,
r20_off = -10,
call_wrapper_off = -8,
result_off = -7,
result_type_off = -6,
method_off = -5,
entry_point_off = -4,
parameter_size_off = -2,
thread_off = -1,
fp_f = 0,
retaddr_off = 1,
};
address generate_call_stub(address& return_address) {
assert((int)frame::entry_frame_after_call_words == -(int)sp_after_call_off + 1 &&
(int)frame::entry_frame_call_wrapper_offset == (int)call_wrapper_off,
"adjust this code");
StubCodeMark mark(this, "StubRoutines", "call_stub");
address start = __ pc();
const Address sp_after_call(rfp, sp_after_call_off * wordSize);
const Address call_wrapper (rfp, call_wrapper_off * wordSize);
const Address result (rfp, result_off * wordSize);
const Address result_type (rfp, result_type_off * wordSize);
const Address method (rfp, method_off * wordSize);
const Address entry_point (rfp, entry_point_off * wordSize);
const Address parameter_size(rfp, parameter_size_off * wordSize);
const Address thread (rfp, thread_off * wordSize);
const Address d15_save (rfp, d15_off * wordSize);
const Address d13_save (rfp, d13_off * wordSize);
const Address d11_save (rfp, d11_off * wordSize);
const Address d9_save (rfp, d9_off * wordSize);
const Address r28_save (rfp, r28_off * wordSize);
const Address r26_save (rfp, r26_off * wordSize);
const Address r24_save (rfp, r24_off * wordSize);
const Address r22_save (rfp, r22_off * wordSize);
const Address r20_save (rfp, r20_off * wordSize);
// stub code
address aarch64_entry = __ pc();
// set up frame and move sp to end of save area
__ enter();
__ sub(sp, rfp, -sp_after_call_off * wordSize);
// save register parameters and Java scratch/global registers
// n.b. we save thread even though it gets installed in
// rthread because we want to sanity check rthread later
__ str(c_rarg7, thread);
__ strw(c_rarg6, parameter_size);
__ stp(c_rarg4, c_rarg5, entry_point);
__ stp(c_rarg2, c_rarg3, result_type);
__ stp(c_rarg0, c_rarg1, call_wrapper);
__ stp(r20, r19, r20_save);
__ stp(r22, r21, r22_save);
__ stp(r24, r23, r24_save);
__ stp(r26, r25, r26_save);
__ stp(r28, r27, r28_save);
__ stpd(v9, v8, d9_save);
__ stpd(v11, v10, d11_save);
__ stpd(v13, v12, d13_save);
__ stpd(v15, v14, d15_save);
// install Java thread in global register now we have saved
// whatever value it held
__ mov(rthread, c_rarg7);
// And method
__ mov(rmethod, c_rarg3);
// set up the heapbase register
__ reinit_heapbase();
#ifdef ASSERT
// make sure we have no pending exceptions
{
Label L;
__ ldr(rscratch1, Address(rthread, in_bytes(Thread::pending_exception_offset())));
__ cmp(rscratch1, (u1)NULL_WORD);
__ br(Assembler::EQ, L);
__ stop("StubRoutines::call_stub: entered with pending exception");
__ BIND(L);
}
#endif
// pass parameters if any
__ mov(esp, sp);
__ sub(rscratch1, sp, c_rarg6, ext::uxtw, LogBytesPerWord); // Move SP out of the way
__ andr(sp, rscratch1, -2 * wordSize);
BLOCK_COMMENT("pass parameters if any");
Label parameters_done;
// parameter count is still in c_rarg6
// and parameter pointer identifying param 1 is in c_rarg5
__ cbzw(c_rarg6, parameters_done);
address loop = __ pc();
__ ldr(rscratch1, Address(__ post(c_rarg5, wordSize)));
__ subsw(c_rarg6, c_rarg6, 1);
__ push(rscratch1);
__ br(Assembler::GT, loop);
__ BIND(parameters_done);
// call Java entry -- passing methdoOop, and current sp
// rmethod: Method*
// r19_sender_sp: sender sp
BLOCK_COMMENT("call Java function");
__ mov(r19_sender_sp, sp);
__ blr(c_rarg4);
// we do this here because the notify will already have been done
// if we get to the next instruction via an exception
//
// n.b. adding this instruction here affects the calculation of
// whether or not a routine returns to the call stub (used when
// doing stack walks) since the normal test is to check the return
// pc against the address saved below. so we may need to allow for
// this extra instruction in the check.
// save current address for use by exception handling code
return_address = __ pc();
// store result depending on type (everything that is not
// T_OBJECT, T_LONG, T_FLOAT or T_DOUBLE is treated as T_INT)
// n.b. this assumes Java returns an integral result in r0
// and a floating result in j_farg0
__ ldr(j_rarg2, result);
Label is_long, is_float, is_double, exit;
__ ldr(j_rarg1, result_type);
__ cmp(j_rarg1, (u1)T_OBJECT);
__ br(Assembler::EQ, is_long);
__ cmp(j_rarg1, (u1)T_LONG);
__ br(Assembler::EQ, is_long);
__ cmp(j_rarg1, (u1)T_FLOAT);
__ br(Assembler::EQ, is_float);
__ cmp(j_rarg1, (u1)T_DOUBLE);
__ br(Assembler::EQ, is_double);
// handle T_INT case
__ strw(r0, Address(j_rarg2));
__ BIND(exit);
// pop parameters
__ sub(esp, rfp, -sp_after_call_off * wordSize);
#ifdef ASSERT
// verify that threads correspond
{
Label L, S;
__ ldr(rscratch1, thread);
__ cmp(rthread, rscratch1);
__ br(Assembler::NE, S);
__ get_thread(rscratch1);
__ cmp(rthread, rscratch1);
__ br(Assembler::EQ, L);
__ BIND(S);
__ stop("StubRoutines::call_stub: threads must correspond");
__ BIND(L);
}
#endif
__ pop_cont_fastpath(rthread);
// restore callee-save registers
__ ldpd(v15, v14, d15_save);
__ ldpd(v13, v12, d13_save);
__ ldpd(v11, v10, d11_save);
__ ldpd(v9, v8, d9_save);
__ ldp(r28, r27, r28_save);
__ ldp(r26, r25, r26_save);
__ ldp(r24, r23, r24_save);
__ ldp(r22, r21, r22_save);
__ ldp(r20, r19, r20_save);
__ ldp(c_rarg0, c_rarg1, call_wrapper);
__ ldrw(c_rarg2, result_type);
__ ldr(c_rarg3, method);
__ ldp(c_rarg4, c_rarg5, entry_point);
__ ldp(c_rarg6, c_rarg7, parameter_size);
// leave frame and return to caller
__ leave();
__ ret(lr);
// handle return types different from T_INT
__ BIND(is_long);
__ str(r0, Address(j_rarg2, 0));
__ br(Assembler::AL, exit);
__ BIND(is_float);
__ strs(j_farg0, Address(j_rarg2, 0));
__ br(Assembler::AL, exit);
__ BIND(is_double);
__ strd(j_farg0, Address(j_rarg2, 0));
__ br(Assembler::AL, exit);
return start;
}
// Return point for a Java call if there's an exception thrown in
// Java code. The exception is caught and transformed into a
// pending exception stored in JavaThread that can be tested from
// within the VM.
//
// Note: Usually the parameters are removed by the callee. In case
// of an exception crossing an activation frame boundary, that is
// not the case if the callee is compiled code => need to setup the
// rsp.
//
// r0: exception oop
address generate_catch_exception() {
StubCodeMark mark(this, "StubRoutines", "catch_exception");
address start = __ pc();
// same as in generate_call_stub():
const Address sp_after_call(rfp, sp_after_call_off * wordSize);
const Address thread (rfp, thread_off * wordSize);
#ifdef ASSERT
// verify that threads correspond
{
Label L, S;
__ ldr(rscratch1, thread);
__ cmp(rthread, rscratch1);
__ br(Assembler::NE, S);
__ get_thread(rscratch1);
__ cmp(rthread, rscratch1);
__ br(Assembler::EQ, L);
__ bind(S);
__ stop("StubRoutines::catch_exception: threads must correspond");
__ bind(L);
}
#endif
// set pending exception
__ verify_oop(r0);
__ str(r0, Address(rthread, Thread::pending_exception_offset()));
__ mov(rscratch1, (address)__FILE__);
__ str(rscratch1, Address(rthread, Thread::exception_file_offset()));
__ movw(rscratch1, (int)__LINE__);
__ strw(rscratch1, Address(rthread, Thread::exception_line_offset()));
// complete return to VM
assert(StubRoutines::_call_stub_return_address != NULL,
"_call_stub_return_address must have been generated before");
__ b(StubRoutines::_call_stub_return_address);
return start;
}
// Continuation point for runtime calls returning with a pending
// exception. The pending exception check happened in the runtime
// or native call stub. The pending exception in Thread is
// converted into a Java-level exception.
//
// Contract with Java-level exception handlers:
// r0: exception
// r3: throwing pc
//
// NOTE: At entry of this stub, exception-pc must be in LR !!
// NOTE: this is always used as a jump target within generated code
// so it just needs to be generated code with no x86 prolog
address generate_forward_exception() {
StubCodeMark mark(this, "StubRoutines", "forward exception");
address start = __ pc();
// Upon entry, LR points to the return address returning into
// Java (interpreted or compiled) code; i.e., the return address
// becomes the throwing pc.
//
// Arguments pushed before the runtime call are still on the stack
// but the exception handler will reset the stack pointer ->
// ignore them. A potential result in registers can be ignored as
// well.
#ifdef ASSERT
// make sure this code is only executed if there is a pending exception
{
Label L;
__ ldr(rscratch1, Address(rthread, Thread::pending_exception_offset()));
__ cbnz(rscratch1, L);
__ stop("StubRoutines::forward exception: no pending exception (1)");
__ bind(L);
}
#endif
// compute exception handler into r19
// call the VM to find the handler address associated with the
// caller address. pass thread in r0 and caller pc (ret address)
// in r1. n.b. the caller pc is in lr, unlike x86 where it is on
// the stack.
__ mov(c_rarg1, lr);
// lr will be trashed by the VM call so we move it to R19
// (callee-saved) because we also need to pass it to the handler
// returned by this call.
__ mov(r19, lr);
BLOCK_COMMENT("call exception_handler_for_return_address");
__ call_VM_leaf(CAST_FROM_FN_PTR(address,
SharedRuntime::exception_handler_for_return_address),
rthread, c_rarg1);
// Reinitialize the ptrue predicate register, in case the external runtime
// call clobbers ptrue reg, as we may return to SVE compiled code.
__ reinitialize_ptrue();
// we should not really care that lr is no longer the callee
// address. we saved the value the handler needs in r19 so we can
// just copy it to r3. however, the C2 handler will push its own
// frame and then calls into the VM and the VM code asserts that
// the PC for the frame above the handler belongs to a compiled
// Java method. So, we restore lr here to satisfy that assert.
__ mov(lr, r19);
// setup r0 & r3 & clear pending exception
__ mov(r3, r19);
__ mov(r19, r0);
__ ldr(r0, Address(rthread, Thread::pending_exception_offset()));
__ str(zr, Address(rthread, Thread::pending_exception_offset()));
#ifdef ASSERT
// make sure exception is set
{
Label L;
__ cbnz(r0, L);
__ stop("StubRoutines::forward exception: no pending exception (2)");
__ bind(L);
}
#endif
// continue at exception handler
// r0: exception
// r3: throwing pc
// r19: exception handler
__ verify_oop(r0);
__ br(r19);
return start;
}
// Non-destructive plausibility checks for oops
//
// Arguments:
// r0: oop to verify
// rscratch1: error message
//
// Stack after saving c_rarg3:
// [tos + 0]: saved c_rarg3
// [tos + 1]: saved c_rarg2
// [tos + 2]: saved lr
// [tos + 3]: saved rscratch2
// [tos + 4]: saved r0
// [tos + 5]: saved rscratch1
address generate_verify_oop() {
StubCodeMark mark(this, "StubRoutines", "verify_oop");
address start = __ pc();
Label exit, error;
// save c_rarg2 and c_rarg3
__ stp(c_rarg3, c_rarg2, Address(__ pre(sp, -16)));
// __ incrementl(ExternalAddress((address) StubRoutines::verify_oop_count_addr()));
__ lea(c_rarg2, ExternalAddress((address) StubRoutines::verify_oop_count_addr()));
__ ldr(c_rarg3, Address(c_rarg2));
__ add(c_rarg3, c_rarg3, 1);
__ str(c_rarg3, Address(c_rarg2));
// object is in r0
// make sure object is 'reasonable'
__ cbz(r0, exit); // if obj is NULL it is OK
#if INCLUDE_ZGC
if (UseZGC) {
// Check if mask is good.
// verifies that ZAddressBadMask & r0 == 0
__ ldr(c_rarg3, Address(rthread, ZThreadLocalData::address_bad_mask_offset()));
__ andr(c_rarg2, r0, c_rarg3);
__ cbnz(c_rarg2, error);
}
#endif
// Check if the oop is in the right area of memory
__ mov(c_rarg3, (intptr_t) Universe::verify_oop_mask());
__ andr(c_rarg2, r0, c_rarg3);
__ mov(c_rarg3, (intptr_t) Universe::verify_oop_bits());
// Compare c_rarg2 and c_rarg3. We don't use a compare
// instruction here because the flags register is live.
__ eor(c_rarg2, c_rarg2, c_rarg3);
__ cbnz(c_rarg2, error);
// make sure klass is 'reasonable', which is not zero.
// NOTE: We used to load the Klass* here, and compare that to zero.
// However, with current Lilliput implementation, that would require
// checking the locking bits and calling into the runtime, which
// clobbers the condition flags, which may be live around this call.
// OTOH, this is a simple NULL-check, and we can simply load the upper
// 32bit of the header as narrowKlass, and compare that to 0. The
// worst that can happen (rarely) is that the object is locked and
// we have lock pointer bits in the upper 32bits. We can't get a false
// negative.
assert(oopDesc::klass_offset_in_bytes() % 4 == 0, "must be 4 byte aligned");
__ ldrw(r0, Address(r0, oopDesc::klass_offset_in_bytes())); // get klass
__ cbzw(r0, error); // if klass is NULL it is broken
// return if everything seems ok
__ bind(exit);
__ ldp(c_rarg3, c_rarg2, Address(__ post(sp, 16)));
__ ret(lr);
// handle errors
__ bind(error);
__ ldp(c_rarg3, c_rarg2, Address(__ post(sp, 16)));
__ push(RegSet::range(r0, r29), sp);
// debug(char* msg, int64_t pc, int64_t regs[])
__ mov(c_rarg0, rscratch1); // pass address of error message
__ mov(c_rarg1, lr); // pass return address
__ mov(c_rarg2, sp); // pass address of regs on stack
#ifndef PRODUCT
assert(frame::arg_reg_save_area_bytes == 0, "not expecting frame reg save area");
#endif
BLOCK_COMMENT("call MacroAssembler::debug");
__ mov(rscratch1, CAST_FROM_FN_PTR(address, MacroAssembler::debug64));
__ blr(rscratch1);
__ hlt(0);
return start;
}
// Generate indices for iota vector.
address generate_iota_indices(const char *stub_name) {
__ align(CodeEntryAlignment);
StubCodeMark mark(this, "StubRoutines", stub_name);
address start = __ pc();
// B
__ emit_data64(0x0706050403020100, relocInfo::none);
__ emit_data64(0x0F0E0D0C0B0A0908, relocInfo::none);
// H
__ emit_data64(0x0003000200010000, relocInfo::none);
__ emit_data64(0x0007000600050004, relocInfo::none);
// S
__ emit_data64(0x0000000100000000, relocInfo::none);
__ emit_data64(0x0000000300000002, relocInfo::none);
// D
__ emit_data64(0x0000000000000000, relocInfo::none);
__ emit_data64(0x0000000000000001, relocInfo::none);
// S - FP
__ emit_data64(0x3F80000000000000, relocInfo::none); // 0.0f, 1.0f
__ emit_data64(0x4040000040000000, relocInfo::none); // 2.0f, 3.0f
// D - FP
__ emit_data64(0x0000000000000000, relocInfo::none); // 0.0d
__ emit_data64(0x3FF0000000000000, relocInfo::none); // 1.0d
return start;
}
// The inner part of zero_words(). This is the bulk operation,
// zeroing words in blocks, possibly using DC ZVA to do it. The
// caller is responsible for zeroing the last few words.
//
// Inputs:
// r10: the HeapWord-aligned base address of an array to zero.
// r11: the count in HeapWords, r11 > 0.
//
// Returns r10 and r11, adjusted for the caller to clear.
// r10: the base address of the tail of words left to clear.
// r11: the number of words in the tail.
// r11 < MacroAssembler::zero_words_block_size.
address generate_zero_blocks() {
Label done;
Label base_aligned;
Register base = r10, cnt = r11;
__ align(CodeEntryAlignment);
StubCodeMark mark(this, "StubRoutines", "zero_blocks");
address start = __ pc();
if (UseBlockZeroing) {
int zva_length = VM_Version::zva_length();
// Ensure ZVA length can be divided by 16. This is required by
// the subsequent operations.
assert (zva_length % 16 == 0, "Unexpected ZVA Length");
__ tbz(base, 3, base_aligned);
__ str(zr, Address(__ post(base, 8)));
__ sub(cnt, cnt, 1);
__ bind(base_aligned);
// Ensure count >= zva_length * 2 so that it still deserves a zva after
// alignment.
Label small;
int low_limit = MAX2(zva_length * 2, (int)BlockZeroingLowLimit);
__ subs(rscratch1, cnt, low_limit >> 3);
__ br(Assembler::LT, small);
__ zero_dcache_blocks(base, cnt);
__ bind(small);
}
{
// Number of stp instructions we'll unroll
const int unroll =
MacroAssembler::zero_words_block_size / 2;
// Clear the remaining blocks.
Label loop;
__ subs(cnt, cnt, unroll * 2);
__ br(Assembler::LT, done);
__ bind(loop);
for (int i = 0; i < unroll; i++)
__ stp(zr, zr, __ post(base, 16));
__ subs(cnt, cnt, unroll * 2);
__ br(Assembler::GE, loop);
__ bind(done);
__ add(cnt, cnt, unroll * 2);
}
__ ret(lr);
return start;
}
typedef enum {
copy_forwards = 1,
copy_backwards = -1
} copy_direction;
// Bulk copy of blocks of 8 words.
//
// count is a count of words.
//
// Precondition: count >= 8
//
// Postconditions:
//
// The least significant bit of count contains the remaining count
// of words to copy. The rest of count is trash.
//
// s and d are adjusted to point to the remaining words to copy
//
void generate_copy_longs(Label &start, Register s, Register d, Register count,
copy_direction direction) {
int unit = wordSize * direction;
int bias = (UseSIMDForMemoryOps ? 4:2) * wordSize;
const Register t0 = r3, t1 = r4, t2 = r5, t3 = r6,
t4 = r7, t5 = r10, t6 = r11, t7 = r12;
const Register stride = r13;
assert_different_registers(rscratch1, t0, t1, t2, t3, t4, t5, t6, t7);
assert_different_registers(s, d, count, rscratch1);
Label again, drain;
const char *stub_name;
if (direction == copy_forwards)
stub_name = "forward_copy_longs";
else
stub_name = "backward_copy_longs";
__ align(CodeEntryAlignment);
StubCodeMark mark(this, "StubRoutines", stub_name);
__ bind(start);
Label unaligned_copy_long;
if (AvoidUnalignedAccesses) {
__ tbnz(d, 3, unaligned_copy_long);
}
if (direction == copy_forwards) {
__ sub(s, s, bias);
__ sub(d, d, bias);
}
#ifdef ASSERT
// Make sure we are never given < 8 words
{
Label L;
__ cmp(count, (u1)8);
__ br(Assembler::GE, L);
__ stop("genrate_copy_longs called with < 8 words");
__ bind(L);
}
#endif
// Fill 8 registers
if (UseSIMDForMemoryOps) {
__ ldpq(v0, v1, Address(s, 4 * unit));
__ ldpq(v2, v3, Address(__ pre(s, 8 * unit)));
} else {
__ ldp(t0, t1, Address(s, 2 * unit));
__ ldp(t2, t3, Address(s, 4 * unit));
__ ldp(t4, t5, Address(s, 6 * unit));
__ ldp(t6, t7, Address(__ pre(s, 8 * unit)));
}
__ subs(count, count, 16);
__ br(Assembler::LO, drain);
int prefetch = PrefetchCopyIntervalInBytes;
bool use_stride = false;
if (direction == copy_backwards) {
use_stride = prefetch > 256;
prefetch = -prefetch;
if (use_stride) __ mov(stride, prefetch);
}
__ bind(again);
if (PrefetchCopyIntervalInBytes > 0)
__ prfm(use_stride ? Address(s, stride) : Address(s, prefetch), PLDL1KEEP);
if (UseSIMDForMemoryOps) {
__ stpq(v0, v1, Address(d, 4 * unit));
__ ldpq(v0, v1, Address(s, 4 * unit));
__ stpq(v2, v3, Address(__ pre(d, 8 * unit)));
__ ldpq(v2, v3, Address(__ pre(s, 8 * unit)));
} else {
__ stp(t0, t1, Address(d, 2 * unit));
__ ldp(t0, t1, Address(s, 2 * unit));
__ stp(t2, t3, Address(d, 4 * unit));
__ ldp(t2, t3, Address(s, 4 * unit));
__ stp(t4, t5, Address(d, 6 * unit));
__ ldp(t4, t5, Address(s, 6 * unit));
__ stp(t6, t7, Address(__ pre(d, 8 * unit)));
__ ldp(t6, t7, Address(__ pre(s, 8 * unit)));
}
__ subs(count, count, 8);
__ br(Assembler::HS, again);
// Drain
__ bind(drain);
if (UseSIMDForMemoryOps) {
__ stpq(v0, v1, Address(d, 4 * unit));
__ stpq(v2, v3, Address(__ pre(d, 8 * unit)));
} else {
__ stp(t0, t1, Address(d, 2 * unit));
__ stp(t2, t3, Address(d, 4 * unit));
__ stp(t4, t5, Address(d, 6 * unit));
__ stp(t6, t7, Address(__ pre(d, 8 * unit)));
}
{
Label L1, L2;
__ tbz(count, exact_log2(4), L1);
if (UseSIMDForMemoryOps) {
__ ldpq(v0, v1, Address(__ pre(s, 4 * unit)));
__ stpq(v0, v1, Address(__ pre(d, 4 * unit)));
} else {
__ ldp(t0, t1, Address(s, 2 * unit));
__ ldp(t2, t3, Address(__ pre(s, 4 * unit)));
__ stp(t0, t1, Address(d, 2 * unit));
__ stp(t2, t3, Address(__ pre(d, 4 * unit)));
}
__ bind(L1);
if (direction == copy_forwards) {
__ add(s, s, bias);
__ add(d, d, bias);
}
__ tbz(count, 1, L2);
__ ldp(t0, t1, Address(__ adjust(s, 2 * unit, direction == copy_backwards)));
__ stp(t0, t1, Address(__ adjust(d, 2 * unit, direction == copy_backwards)));
__ bind(L2);
}
__ ret(lr);
if (AvoidUnalignedAccesses) {
Label drain, again;
// Register order for storing. Order is different for backward copy.
__ bind(unaligned_copy_long);
// source address is even aligned, target odd aligned
//
// when forward copying word pairs we read long pairs at offsets
// {0, 2, 4, 6} (in long words). when backwards copying we read
// long pairs at offsets {-2, -4, -6, -8}. We adjust the source
// address by -2 in the forwards case so we can compute the
// source offsets for both as {2, 4, 6, 8} * unit where unit = 1
// or -1.
//
// when forward copying we need to store 1 word, 3 pairs and
// then 1 word at offsets {0, 1, 3, 5, 7}. Rather than use a
// zero offset We adjust the destination by -1 which means we
// have to use offsets { 1, 2, 4, 6, 8} * unit for the stores.
//
// When backwards copyng we need to store 1 word, 3 pairs and
// then 1 word at offsets {-1, -3, -5, -7, -8} i.e. we use
// offsets {1, 3, 5, 7, 8} * unit.
if (direction == copy_forwards) {
__ sub(s, s, 16);
__ sub(d, d, 8);
}
// Fill 8 registers
//
// for forwards copy s was offset by -16 from the original input
// value of s so the register contents are at these offsets
// relative to the 64 bit block addressed by that original input
// and so on for each successive 64 byte block when s is updated
//
// t0 at offset 0, t1 at offset 8
// t2 at offset 16, t3 at offset 24
// t4 at offset 32, t5 at offset 40
// t6 at offset 48, t7 at offset 56
// for backwards copy s was not offset so the register contents
// are at these offsets into the preceding 64 byte block
// relative to that original input and so on for each successive
// preceding 64 byte block when s is updated. this explains the
// slightly counter-intuitive looking pattern of register usage
// in the stp instructions for backwards copy.
//
// t0 at offset -16, t1 at offset -8
// t2 at offset -32, t3 at offset -24
// t4 at offset -48, t5 at offset -40
// t6 at offset -64, t7 at offset -56
__ ldp(t0, t1, Address(s, 2 * unit));
__ ldp(t2, t3, Address(s, 4 * unit));
__ ldp(t4, t5, Address(s, 6 * unit));
__ ldp(t6, t7, Address(__ pre(s, 8 * unit)));
__ subs(count, count, 16);
__ br(Assembler::LO, drain);
int prefetch = PrefetchCopyIntervalInBytes;
bool use_stride = false;
if (direction == copy_backwards) {
use_stride = prefetch > 256;
prefetch = -prefetch;
if (use_stride) __ mov(stride, prefetch);
}
__ bind(again);
if (PrefetchCopyIntervalInBytes > 0)
__ prfm(use_stride ? Address(s, stride) : Address(s, prefetch), PLDL1KEEP);
if (direction == copy_forwards) {
// allowing for the offset of -8 the store instructions place
// registers into the target 64 bit block at the following
// offsets
//
// t0 at offset 0
// t1 at offset 8, t2 at offset 16
// t3 at offset 24, t4 at offset 32
// t5 at offset 40, t6 at offset 48
// t7 at offset 56
__ str(t0, Address(d, 1 * unit));
__ stp(t1, t2, Address(d, 2 * unit));
__ ldp(t0, t1, Address(s, 2 * unit));
__ stp(t3, t4, Address(d, 4 * unit));
__ ldp(t2, t3, Address(s, 4 * unit));
__ stp(t5, t6, Address(d, 6 * unit));
__ ldp(t4, t5, Address(s, 6 * unit));
__ str(t7, Address(__ pre(d, 8 * unit)));
__ ldp(t6, t7, Address(__ pre(s, 8 * unit)));
} else {
// d was not offset when we started so the registers are
// written into the 64 bit block preceding d with the following
// offsets
//
// t1 at offset -8
// t3 at offset -24, t0 at offset -16
// t5 at offset -48, t2 at offset -32
// t7 at offset -56, t4 at offset -48
// t6 at offset -64
//
// note that this matches the offsets previously noted for the
// loads
__ str(t1, Address(d, 1 * unit));
__ stp(t3, t0, Address(d, 3 * unit));
__ ldp(t0, t1, Address(s, 2 * unit));
__ stp(t5, t2, Address(d, 5 * unit));
__ ldp(t2, t3, Address(s, 4 * unit));
__ stp(t7, t4, Address(d, 7 * unit));
__ ldp(t4, t5, Address(s, 6 * unit));
__ str(t6, Address(__ pre(d, 8 * unit)));
__ ldp(t6, t7, Address(__ pre(s, 8 * unit)));
}
__ subs(count, count, 8);
__ br(Assembler::HS, again);
// Drain
//
// this uses the same pattern of offsets and register arguments
// as above
__ bind(drain);