8028471: PPC64 (part 215): opto: Extend ImplicitNullCheck optimization.
Summary: Fixed Implicit NULL check optimization for AIX, where the page at address '0' is only write-protected.
Reviewed-by: kvn
/*
* Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright 2012, 2013 SAP AG. 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.inline.hpp"
#include "compiler/disassembler.hpp"
#include "gc_interface/collectedHeap.inline.hpp"
#include "interpreter/interpreter.hpp"
#include "memory/cardTableModRefBS.hpp"
#include "memory/resourceArea.hpp"
#include "prims/methodHandles.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/interfaceSupport.hpp"
#include "runtime/objectMonitor.hpp"
#include "runtime/os.hpp"
#include "runtime/sharedRuntime.hpp"
#include "runtime/stubRoutines.hpp"
#include "utilities/macros.hpp"
#if INCLUDE_ALL_GCS
#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
#include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
#include "gc_implementation/g1/heapRegion.hpp"
#endif // INCLUDE_ALL_GCS
#ifdef PRODUCT
#define BLOCK_COMMENT(str) // nothing
#else
#define BLOCK_COMMENT(str) block_comment(str)
#endif
#ifdef ASSERT
// On RISC, there's no benefit to verifying instruction boundaries.
bool AbstractAssembler::pd_check_instruction_mark() { return false; }
#endif
void MacroAssembler::ld_largeoffset_unchecked(Register d, int si31, Register a, int emit_filler_nop) {
assert(Assembler::is_simm(si31, 31) && si31 >= 0, "si31 out of range");
if (Assembler::is_simm(si31, 16)) {
ld(d, si31, a);
if (emit_filler_nop) nop();
} else {
const int hi = MacroAssembler::largeoffset_si16_si16_hi(si31);
const int lo = MacroAssembler::largeoffset_si16_si16_lo(si31);
addis(d, a, hi);
ld(d, lo, d);
}
}
void MacroAssembler::ld_largeoffset(Register d, int si31, Register a, int emit_filler_nop) {
assert_different_registers(d, a);
ld_largeoffset_unchecked(d, si31, a, emit_filler_nop);
}
void MacroAssembler::load_sized_value(Register dst, RegisterOrConstant offs, Register base,
size_t size_in_bytes, bool is_signed) {
switch (size_in_bytes) {
case 8: ld(dst, offs, base); break;
case 4: is_signed ? lwa(dst, offs, base) : lwz(dst, offs, base); break;
case 2: is_signed ? lha(dst, offs, base) : lhz(dst, offs, base); break;
case 1: lbz(dst, offs, base); if (is_signed) extsb(dst, dst); break; // lba doesn't exist :(
default: ShouldNotReachHere();
}
}
void MacroAssembler::store_sized_value(Register dst, RegisterOrConstant offs, Register base,
size_t size_in_bytes) {
switch (size_in_bytes) {
case 8: std(dst, offs, base); break;
case 4: stw(dst, offs, base); break;
case 2: sth(dst, offs, base); break;
case 1: stb(dst, offs, base); break;
default: ShouldNotReachHere();
}
}
void MacroAssembler::align(int modulus) {
while (offset() % modulus != 0) nop();
}
// Issue instructions that calculate given TOC from global TOC.
void MacroAssembler::calculate_address_from_global_toc(Register dst, address addr, bool hi16, bool lo16,
bool add_relocation, bool emit_dummy_addr) {
int offset = -1;
if (emit_dummy_addr) {
offset = -128; // dummy address
} else if (addr != (address)(intptr_t)-1) {
offset = MacroAssembler::offset_to_global_toc(addr);
}
if (hi16) {
addis(dst, R29, MacroAssembler::largeoffset_si16_si16_hi(offset));
}
if (lo16) {
if (add_relocation) {
// Relocate at the addi to avoid confusion with a load from the method's TOC.
relocate(internal_word_Relocation::spec(addr));
}
addi(dst, dst, MacroAssembler::largeoffset_si16_si16_lo(offset));
}
}
int MacroAssembler::patch_calculate_address_from_global_toc_at(address a, address bound, address addr) {
const int offset = MacroAssembler::offset_to_global_toc(addr);
const address inst2_addr = a;
const int inst2 = *(int *)inst2_addr;
// The relocation points to the second instruction, the addi,
// and the addi reads and writes the same register dst.
const int dst = inv_rt_field(inst2);
assert(is_addi(inst2) && inv_ra_field(inst2) == dst, "must be addi reading and writing dst");
// Now, find the preceding addis which writes to dst.
int inst1 = 0;
address inst1_addr = inst2_addr - BytesPerInstWord;
while (inst1_addr >= bound) {
inst1 = *(int *) inst1_addr;
if (is_addis(inst1) && inv_rt_field(inst1) == dst) {
// Stop, found the addis which writes dst.
break;
}
inst1_addr -= BytesPerInstWord;
}
assert(is_addis(inst1) && inv_ra_field(inst1) == 29 /* R29 */, "source must be global TOC");
set_imm((int *)inst1_addr, MacroAssembler::largeoffset_si16_si16_hi(offset));
set_imm((int *)inst2_addr, MacroAssembler::largeoffset_si16_si16_lo(offset));
return (int)((intptr_t)addr - (intptr_t)inst1_addr);
}
address MacroAssembler::get_address_of_calculate_address_from_global_toc_at(address a, address bound) {
const address inst2_addr = a;
const int inst2 = *(int *)inst2_addr;
// The relocation points to the second instruction, the addi,
// and the addi reads and writes the same register dst.
const int dst = inv_rt_field(inst2);
assert(is_addi(inst2) && inv_ra_field(inst2) == dst, "must be addi reading and writing dst");
// Now, find the preceding addis which writes to dst.
int inst1 = 0;
address inst1_addr = inst2_addr - BytesPerInstWord;
while (inst1_addr >= bound) {
inst1 = *(int *) inst1_addr;
if (is_addis(inst1) && inv_rt_field(inst1) == dst) {
// stop, found the addis which writes dst
break;
}
inst1_addr -= BytesPerInstWord;
}
assert(is_addis(inst1) && inv_ra_field(inst1) == 29 /* R29 */, "source must be global TOC");
int offset = (get_imm(inst1_addr, 0) << 16) + get_imm(inst2_addr, 0);
// -1 is a special case
if (offset == -1) {
return (address)(intptr_t)-1;
} else {
return global_toc() + offset;
}
}
#ifdef _LP64
// Patch compressed oops or klass constants.
int MacroAssembler::patch_set_narrow_oop(address a, address bound, narrowOop data) {
assert(UseCompressedOops, "Should only patch compressed oops");
const address inst2_addr = a;
const int inst2 = *(int *)inst2_addr;
// The relocation points to the second instruction, the addi,
// and the addi reads and writes the same register dst.
const int dst = inv_rt_field(inst2);
assert(is_addi(inst2) && inv_ra_field(inst2) == dst, "must be addi reading and writing dst");
// Now, find the preceding addis which writes to dst.
int inst1 = 0;
address inst1_addr = inst2_addr - BytesPerInstWord;
bool inst1_found = false;
while (inst1_addr >= bound) {
inst1 = *(int *)inst1_addr;
if (is_lis(inst1) && inv_rs_field(inst1) == dst) { inst1_found = true; break; }
inst1_addr -= BytesPerInstWord;
}
assert(inst1_found, "inst is not lis");
int xc = (data >> 16) & 0xffff;
int xd = (data >> 0) & 0xffff;
set_imm((int *)inst1_addr,((short)(xc + ((xd & 0x8000) != 0 ? 1 : 0)))); // see enc_load_con_narrow1/2
set_imm((int *)inst2_addr, (short)(xd));
return (int)((intptr_t)inst2_addr - (intptr_t)inst1_addr);
}
// Get compressed oop or klass constant.
narrowOop MacroAssembler::get_narrow_oop(address a, address bound) {
assert(UseCompressedOops, "Should only patch compressed oops");
const address inst2_addr = a;
const int inst2 = *(int *)inst2_addr;
// The relocation points to the second instruction, the addi,
// and the addi reads and writes the same register dst.
const int dst = inv_rt_field(inst2);
assert(is_addi(inst2) && inv_ra_field(inst2) == dst, "must be addi reading and writing dst");
// Now, find the preceding lis which writes to dst.
int inst1 = 0;
address inst1_addr = inst2_addr - BytesPerInstWord;
bool inst1_found = false;
while (inst1_addr >= bound) {
inst1 = *(int *) inst1_addr;
if (is_lis(inst1) && inv_rs_field(inst1) == dst) { inst1_found = true; break;}
inst1_addr -= BytesPerInstWord;
}
assert(inst1_found, "inst is not lis");
uint xl = ((unsigned int) (get_imm(inst2_addr,0) & 0xffff));
uint xh = (((((xl & 0x8000) != 0 ? -1 : 0) + get_imm(inst1_addr,0)) & 0xffff) << 16);
return (int) (xl | xh);
}
#endif // _LP64
void MacroAssembler::load_const_from_method_toc(Register dst, AddressLiteral& a, Register toc) {
int toc_offset = 0;
// Use RelocationHolder::none for the constant pool entry, otherwise
// we will end up with a failing NativeCall::verify(x) where x is
// the address of the constant pool entry.
// FIXME: We should insert relocation information for oops at the constant
// pool entries instead of inserting it at the loads; patching of a constant
// pool entry should be less expensive.
Unimplemented();
if (false) {
address oop_address = address_constant((address)a.value(), RelocationHolder::none);
// Relocate at the pc of the load.
relocate(a.rspec());
toc_offset = (int)(oop_address - code()->consts()->start());
}
ld_largeoffset_unchecked(dst, toc_offset, toc, true);
}
bool MacroAssembler::is_load_const_from_method_toc_at(address a) {
const address inst1_addr = a;
const int inst1 = *(int *)inst1_addr;
// The relocation points to the ld or the addis.
return (is_ld(inst1)) ||
(is_addis(inst1) && inv_ra_field(inst1) != 0);
}
int MacroAssembler::get_offset_of_load_const_from_method_toc_at(address a) {
assert(is_load_const_from_method_toc_at(a), "must be load_const_from_method_toc");
const address inst1_addr = a;
const int inst1 = *(int *)inst1_addr;
if (is_ld(inst1)) {
return inv_d1_field(inst1);
} else if (is_addis(inst1)) {
const int dst = inv_rt_field(inst1);
// Now, find the succeeding ld which reads and writes to dst.
address inst2_addr = inst1_addr + BytesPerInstWord;
int inst2 = 0;
while (true) {
inst2 = *(int *) inst2_addr;
if (is_ld(inst2) && inv_ra_field(inst2) == dst && inv_rt_field(inst2) == dst) {
// Stop, found the ld which reads and writes dst.
break;
}
inst2_addr += BytesPerInstWord;
}
return (inv_d1_field(inst1) << 16) + inv_d1_field(inst2);
}
ShouldNotReachHere();
return 0;
}
// Get the constant from a `load_const' sequence.
long MacroAssembler::get_const(address a) {
assert(is_load_const_at(a), "not a load of a constant");
const int *p = (const int*) a;
unsigned long x = (((unsigned long) (get_imm(a,0) & 0xffff)) << 48);
if (is_ori(*(p+1))) {
x |= (((unsigned long) (get_imm(a,1) & 0xffff)) << 32);
x |= (((unsigned long) (get_imm(a,3) & 0xffff)) << 16);
x |= (((unsigned long) (get_imm(a,4) & 0xffff)));
} else if (is_lis(*(p+1))) {
x |= (((unsigned long) (get_imm(a,2) & 0xffff)) << 32);
x |= (((unsigned long) (get_imm(a,1) & 0xffff)) << 16);
x |= (((unsigned long) (get_imm(a,3) & 0xffff)));
} else {
ShouldNotReachHere();
return (long) 0;
}
return (long) x;
}
// Patch the 64 bit constant of a `load_const' sequence. This is a low
// level procedure. It neither flushes the instruction cache nor is it
// mt safe.
void MacroAssembler::patch_const(address a, long x) {
assert(is_load_const_at(a), "not a load of a constant");
int *p = (int*) a;
if (is_ori(*(p+1))) {
set_imm(0 + p, (x >> 48) & 0xffff);
set_imm(1 + p, (x >> 32) & 0xffff);
set_imm(3 + p, (x >> 16) & 0xffff);
set_imm(4 + p, x & 0xffff);
} else if (is_lis(*(p+1))) {
set_imm(0 + p, (x >> 48) & 0xffff);
set_imm(2 + p, (x >> 32) & 0xffff);
set_imm(1 + p, (x >> 16) & 0xffff);
set_imm(3 + p, x & 0xffff);
} else {
ShouldNotReachHere();
}
}
AddressLiteral MacroAssembler::allocate_metadata_address(Metadata* obj) {
assert(oop_recorder() != NULL, "this assembler needs a Recorder");
int index = oop_recorder()->allocate_metadata_index(obj);
RelocationHolder rspec = metadata_Relocation::spec(index);
return AddressLiteral((address)obj, rspec);
}
AddressLiteral MacroAssembler::constant_metadata_address(Metadata* obj) {
assert(oop_recorder() != NULL, "this assembler needs a Recorder");
int index = oop_recorder()->find_index(obj);
RelocationHolder rspec = metadata_Relocation::spec(index);
return AddressLiteral((address)obj, rspec);
}
AddressLiteral MacroAssembler::allocate_oop_address(jobject obj) {
assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
int oop_index = oop_recorder()->allocate_oop_index(obj);
return AddressLiteral(address(obj), oop_Relocation::spec(oop_index));
}
AddressLiteral MacroAssembler::constant_oop_address(jobject obj) {
assert(oop_recorder() != NULL, "this assembler needs an OopRecorder");
int oop_index = oop_recorder()->find_index(obj);
return AddressLiteral(address(obj), oop_Relocation::spec(oop_index));
}
RegisterOrConstant MacroAssembler::delayed_value_impl(intptr_t* delayed_value_addr,
Register tmp, int offset) {
intptr_t value = *delayed_value_addr;
if (value != 0) {
return RegisterOrConstant(value + offset);
}
// Load indirectly to solve generation ordering problem.
// static address, no relocation
int simm16_offset = load_const_optimized(tmp, delayed_value_addr, noreg, true);
ld(tmp, simm16_offset, tmp); // must be aligned ((xa & 3) == 0)
if (offset != 0) {
addi(tmp, tmp, offset);
}
return RegisterOrConstant(tmp);
}
#ifndef PRODUCT
void MacroAssembler::pd_print_patched_instruction(address branch) {
Unimplemented(); // TODO: PPC port
}
#endif // ndef PRODUCT
// Conditional far branch for destinations encodable in 24+2 bits.
void MacroAssembler::bc_far(int boint, int biint, Label& dest, int optimize) {
// If requested by flag optimize, relocate the bc_far as a
// runtime_call and prepare for optimizing it when the code gets
// relocated.
if (optimize == bc_far_optimize_on_relocate) {
relocate(relocInfo::runtime_call_type);
}
// variant 2:
//
// b!cxx SKIP
// bxx DEST
// SKIP:
//
const int opposite_boint = add_bhint_to_boint(opposite_bhint(inv_boint_bhint(boint)),
opposite_bcond(inv_boint_bcond(boint)));
// We emit two branches.
// First, a conditional branch which jumps around the far branch.
const address not_taken_pc = pc() + 2 * BytesPerInstWord;
const address bc_pc = pc();
bc(opposite_boint, biint, not_taken_pc);
const int bc_instr = *(int*)bc_pc;
assert(not_taken_pc == (address)inv_bd_field(bc_instr, (intptr_t)bc_pc), "postcondition");
assert(opposite_boint == inv_bo_field(bc_instr), "postcondition");
assert(boint == add_bhint_to_boint(opposite_bhint(inv_boint_bhint(inv_bo_field(bc_instr))),
opposite_bcond(inv_boint_bcond(inv_bo_field(bc_instr)))),
"postcondition");
assert(biint == inv_bi_field(bc_instr), "postcondition");
// Second, an unconditional far branch which jumps to dest.
// Note: target(dest) remembers the current pc (see CodeSection::target)
// and returns the current pc if the label is not bound yet; when
// the label gets bound, the unconditional far branch will be patched.
const address target_pc = target(dest);
const address b_pc = pc();
b(target_pc);
assert(not_taken_pc == pc(), "postcondition");
assert(dest.is_bound() || target_pc == b_pc, "postcondition");
}
bool MacroAssembler::is_bc_far_at(address instruction_addr) {
return is_bc_far_variant1_at(instruction_addr) ||
is_bc_far_variant2_at(instruction_addr) ||
is_bc_far_variant3_at(instruction_addr);
}
address MacroAssembler::get_dest_of_bc_far_at(address instruction_addr) {
if (is_bc_far_variant1_at(instruction_addr)) {
const address instruction_1_addr = instruction_addr;
const int instruction_1 = *(int*)instruction_1_addr;
return (address)inv_bd_field(instruction_1, (intptr_t)instruction_1_addr);
} else if (is_bc_far_variant2_at(instruction_addr)) {
const address instruction_2_addr = instruction_addr + 4;
return bxx_destination(instruction_2_addr);
} else if (is_bc_far_variant3_at(instruction_addr)) {
return instruction_addr + 8;
}
// variant 4 ???
ShouldNotReachHere();
return NULL;
}
void MacroAssembler::set_dest_of_bc_far_at(address instruction_addr, address dest) {
if (is_bc_far_variant3_at(instruction_addr)) {
// variant 3, far cond branch to the next instruction, already patched to nops:
//
// nop
// endgroup
// SKIP/DEST:
//
return;
}
// first, extract boint and biint from the current branch
int boint = 0;
int biint = 0;
ResourceMark rm;
const int code_size = 2 * BytesPerInstWord;
CodeBuffer buf(instruction_addr, code_size);
MacroAssembler masm(&buf);
if (is_bc_far_variant2_at(instruction_addr) && dest == instruction_addr + 8) {
// Far branch to next instruction: Optimize it by patching nops (produce variant 3).
masm.nop();
masm.endgroup();
} else {
if (is_bc_far_variant1_at(instruction_addr)) {
// variant 1, the 1st instruction contains the destination address:
//
// bcxx DEST
// endgroup
//
const int instruction_1 = *(int*)(instruction_addr);
boint = inv_bo_field(instruction_1);
biint = inv_bi_field(instruction_1);
} else if (is_bc_far_variant2_at(instruction_addr)) {
// variant 2, the 2nd instruction contains the destination address:
//
// b!cxx SKIP
// bxx DEST
// SKIP:
//
const int instruction_1 = *(int*)(instruction_addr);
boint = add_bhint_to_boint(opposite_bhint(inv_boint_bhint(inv_bo_field(instruction_1))),
opposite_bcond(inv_boint_bcond(inv_bo_field(instruction_1))));
biint = inv_bi_field(instruction_1);
} else {
// variant 4???
ShouldNotReachHere();
}
// second, set the new branch destination and optimize the code
if (dest != instruction_addr + 4 && // the bc_far is still unbound!
masm.is_within_range_of_bcxx(dest, instruction_addr)) {
// variant 1:
//
// bcxx DEST
// endgroup
//
masm.bc(boint, biint, dest);
masm.endgroup();
} else {
// variant 2:
//
// b!cxx SKIP
// bxx DEST
// SKIP:
//
const int opposite_boint = add_bhint_to_boint(opposite_bhint(inv_boint_bhint(boint)),
opposite_bcond(inv_boint_bcond(boint)));
const address not_taken_pc = masm.pc() + 2 * BytesPerInstWord;
masm.bc(opposite_boint, biint, not_taken_pc);
masm.b(dest);
}
}
ICache::invalidate_range(instruction_addr, code_size);
}
// Emit a NOT mt-safe patchable 64 bit absolute call/jump.
void MacroAssembler::bxx64_patchable(address dest, relocInfo::relocType rt, bool link) {
// get current pc
uint64_t start_pc = (uint64_t) pc();
const address pc_of_bl = (address) (start_pc + (6*BytesPerInstWord)); // bl is last
const address pc_of_b = (address) (start_pc + (0*BytesPerInstWord)); // b is first
// relocate here
if (rt != relocInfo::none) {
relocate(rt);
}
if ( ReoptimizeCallSequences &&
(( link && is_within_range_of_b(dest, pc_of_bl)) ||
(!link && is_within_range_of_b(dest, pc_of_b)))) {
// variant 2:
// Emit an optimized, pc-relative call/jump.
if (link) {
// some padding
nop();
nop();
nop();
nop();
nop();
nop();
// do the call
assert(pc() == pc_of_bl, "just checking");
bl(dest, relocInfo::none);
} else {
// do the jump
assert(pc() == pc_of_b, "just checking");
b(dest, relocInfo::none);
// some padding
nop();
nop();
nop();
nop();
nop();
nop();
}
// Assert that we can identify the emitted call/jump.
assert(is_bxx64_patchable_variant2_at((address)start_pc, link),
"can't identify emitted call");
} else {
// variant 1:
mr(R0, R11); // spill R11 -> R0.
// Load the destination address into CTR,
// calculate destination relative to global toc.
calculate_address_from_global_toc(R11, dest, true, true, false);
mtctr(R11);
mr(R11, R0); // spill R11 <- R0.
nop();
// do the call/jump
if (link) {
bctrl();
} else{
bctr();
}
// Assert that we can identify the emitted call/jump.
assert(is_bxx64_patchable_variant1b_at((address)start_pc, link),
"can't identify emitted call");
}
// Assert that we can identify the emitted call/jump.
assert(is_bxx64_patchable_at((address)start_pc, link),
"can't identify emitted call");
assert(get_dest_of_bxx64_patchable_at((address)start_pc, link) == dest,
"wrong encoding of dest address");
}
// Identify a bxx64_patchable instruction.
bool MacroAssembler::is_bxx64_patchable_at(address instruction_addr, bool link) {
return is_bxx64_patchable_variant1b_at(instruction_addr, link)
//|| is_bxx64_patchable_variant1_at(instruction_addr, link)
|| is_bxx64_patchable_variant2_at(instruction_addr, link);
}
// Does the call64_patchable instruction use a pc-relative encoding of
// the call destination?
bool MacroAssembler::is_bxx64_patchable_pcrelative_at(address instruction_addr, bool link) {
// variant 2 is pc-relative
return is_bxx64_patchable_variant2_at(instruction_addr, link);
}
// Identify variant 1.
bool MacroAssembler::is_bxx64_patchable_variant1_at(address instruction_addr, bool link) {
unsigned int* instr = (unsigned int*) instruction_addr;
return (link ? is_bctrl(instr[6]) : is_bctr(instr[6])) // bctr[l]
&& is_mtctr(instr[5]) // mtctr
&& is_load_const_at(instruction_addr);
}
// Identify variant 1b: load destination relative to global toc.
bool MacroAssembler::is_bxx64_patchable_variant1b_at(address instruction_addr, bool link) {
unsigned int* instr = (unsigned int*) instruction_addr;
return (link ? is_bctrl(instr[6]) : is_bctr(instr[6])) // bctr[l]
&& is_mtctr(instr[3]) // mtctr
&& is_calculate_address_from_global_toc_at(instruction_addr + 2*BytesPerInstWord, instruction_addr);
}
// Identify variant 2.
bool MacroAssembler::is_bxx64_patchable_variant2_at(address instruction_addr, bool link) {
unsigned int* instr = (unsigned int*) instruction_addr;
if (link) {
return is_bl (instr[6]) // bl dest is last
&& is_nop(instr[0]) // nop
&& is_nop(instr[1]) // nop
&& is_nop(instr[2]) // nop
&& is_nop(instr[3]) // nop
&& is_nop(instr[4]) // nop
&& is_nop(instr[5]); // nop
} else {
return is_b (instr[0]) // b dest is first
&& is_nop(instr[1]) // nop
&& is_nop(instr[2]) // nop
&& is_nop(instr[3]) // nop
&& is_nop(instr[4]) // nop
&& is_nop(instr[5]) // nop
&& is_nop(instr[6]); // nop
}
}
// Set dest address of a bxx64_patchable instruction.
void MacroAssembler::set_dest_of_bxx64_patchable_at(address instruction_addr, address dest, bool link) {
ResourceMark rm;
int code_size = MacroAssembler::bxx64_patchable_size;
CodeBuffer buf(instruction_addr, code_size);
MacroAssembler masm(&buf);
masm.bxx64_patchable(dest, relocInfo::none, link);
ICache::invalidate_range(instruction_addr, code_size);
}
// Get dest address of a bxx64_patchable instruction.
address MacroAssembler::get_dest_of_bxx64_patchable_at(address instruction_addr, bool link) {
if (is_bxx64_patchable_variant1_at(instruction_addr, link)) {
return (address) (unsigned long) get_const(instruction_addr);
} else if (is_bxx64_patchable_variant2_at(instruction_addr, link)) {
unsigned int* instr = (unsigned int*) instruction_addr;
if (link) {
const int instr_idx = 6; // bl is last
int branchoffset = branch_destination(instr[instr_idx], 0);
return instruction_addr + branchoffset + instr_idx*BytesPerInstWord;
} else {
const int instr_idx = 0; // b is first
int branchoffset = branch_destination(instr[instr_idx], 0);
return instruction_addr + branchoffset + instr_idx*BytesPerInstWord;
}
// Load dest relative to global toc.
} else if (is_bxx64_patchable_variant1b_at(instruction_addr, link)) {
return get_address_of_calculate_address_from_global_toc_at(instruction_addr + 2*BytesPerInstWord,
instruction_addr);
} else {
ShouldNotReachHere();
return NULL;
}
}
// Uses ordering which corresponds to ABI:
// _savegpr0_14: std r14,-144(r1)
// _savegpr0_15: std r15,-136(r1)
// _savegpr0_16: std r16,-128(r1)
void MacroAssembler::save_nonvolatile_gprs(Register dst, int offset) {
std(R14, offset, dst); offset += 8;
std(R15, offset, dst); offset += 8;
std(R16, offset, dst); offset += 8;
std(R17, offset, dst); offset += 8;
std(R18, offset, dst); offset += 8;
std(R19, offset, dst); offset += 8;
std(R20, offset, dst); offset += 8;
std(R21, offset, dst); offset += 8;
std(R22, offset, dst); offset += 8;
std(R23, offset, dst); offset += 8;
std(R24, offset, dst); offset += 8;
std(R25, offset, dst); offset += 8;
std(R26, offset, dst); offset += 8;
std(R27, offset, dst); offset += 8;
std(R28, offset, dst); offset += 8;
std(R29, offset, dst); offset += 8;
std(R30, offset, dst); offset += 8;
std(R31, offset, dst); offset += 8;
stfd(F14, offset, dst); offset += 8;
stfd(F15, offset, dst); offset += 8;
stfd(F16, offset, dst); offset += 8;
stfd(F17, offset, dst); offset += 8;
stfd(F18, offset, dst); offset += 8;
stfd(F19, offset, dst); offset += 8;
stfd(F20, offset, dst); offset += 8;
stfd(F21, offset, dst); offset += 8;
stfd(F22, offset, dst); offset += 8;
stfd(F23, offset, dst); offset += 8;
stfd(F24, offset, dst); offset += 8;
stfd(F25, offset, dst); offset += 8;
stfd(F26, offset, dst); offset += 8;
stfd(F27, offset, dst); offset += 8;
stfd(F28, offset, dst); offset += 8;
stfd(F29, offset, dst); offset += 8;
stfd(F30, offset, dst); offset += 8;
stfd(F31, offset, dst);
}
// Uses ordering which corresponds to ABI:
// _restgpr0_14: ld r14,-144(r1)
// _restgpr0_15: ld r15,-136(r1)
// _restgpr0_16: ld r16,-128(r1)
void MacroAssembler::restore_nonvolatile_gprs(Register src, int offset) {
ld(R14, offset, src); offset += 8;
ld(R15, offset, src); offset += 8;
ld(R16, offset, src); offset += 8;
ld(R17, offset, src); offset += 8;
ld(R18, offset, src); offset += 8;
ld(R19, offset, src); offset += 8;
ld(R20, offset, src); offset += 8;
ld(R21, offset, src); offset += 8;
ld(R22, offset, src); offset += 8;
ld(R23, offset, src); offset += 8;
ld(R24, offset, src); offset += 8;
ld(R25, offset, src); offset += 8;
ld(R26, offset, src); offset += 8;
ld(R27, offset, src); offset += 8;
ld(R28, offset, src); offset += 8;
ld(R29, offset, src); offset += 8;
ld(R30, offset, src); offset += 8;
ld(R31, offset, src); offset += 8;
// FP registers
lfd(F14, offset, src); offset += 8;
lfd(F15, offset, src); offset += 8;
lfd(F16, offset, src); offset += 8;
lfd(F17, offset, src); offset += 8;
lfd(F18, offset, src); offset += 8;
lfd(F19, offset, src); offset += 8;
lfd(F20, offset, src); offset += 8;
lfd(F21, offset, src); offset += 8;
lfd(F22, offset, src); offset += 8;
lfd(F23, offset, src); offset += 8;
lfd(F24, offset, src); offset += 8;
lfd(F25, offset, src); offset += 8;
lfd(F26, offset, src); offset += 8;
lfd(F27, offset, src); offset += 8;
lfd(F28, offset, src); offset += 8;
lfd(F29, offset, src); offset += 8;
lfd(F30, offset, src); offset += 8;
lfd(F31, offset, src);
}
// For verify_oops.
void MacroAssembler::save_volatile_gprs(Register dst, int offset) {
std(R3, offset, dst); offset += 8;
std(R4, offset, dst); offset += 8;
std(R5, offset, dst); offset += 8;
std(R6, offset, dst); offset += 8;
std(R7, offset, dst); offset += 8;
std(R8, offset, dst); offset += 8;
std(R9, offset, dst); offset += 8;
std(R10, offset, dst); offset += 8;
std(R11, offset, dst); offset += 8;
std(R12, offset, dst);
}
// For verify_oops.
void MacroAssembler::restore_volatile_gprs(Register src, int offset) {
ld(R3, offset, src); offset += 8;
ld(R4, offset, src); offset += 8;
ld(R5, offset, src); offset += 8;
ld(R6, offset, src); offset += 8;
ld(R7, offset, src); offset += 8;
ld(R8, offset, src); offset += 8;
ld(R9, offset, src); offset += 8;
ld(R10, offset, src); offset += 8;
ld(R11, offset, src); offset += 8;
ld(R12, offset, src);
}
void MacroAssembler::save_LR_CR(Register tmp) {
mfcr(tmp);
std(tmp, _abi(cr), R1_SP);
mflr(tmp);
std(tmp, _abi(lr), R1_SP);
// Tmp must contain lr on exit! (see return_addr and prolog in ppc64.ad)
}
void MacroAssembler::restore_LR_CR(Register tmp) {
assert(tmp != R1_SP, "must be distinct");
ld(tmp, _abi(lr), R1_SP);
mtlr(tmp);
ld(tmp, _abi(cr), R1_SP);
mtcr(tmp);
}
address MacroAssembler::get_PC_trash_LR(Register result) {
Label L;
bl(L);
bind(L);
address lr_pc = pc();
mflr(result);
return lr_pc;
}
void MacroAssembler::resize_frame(Register offset, Register tmp) {
#ifdef ASSERT
assert_different_registers(offset, tmp, R1_SP);
andi_(tmp, offset, frame::alignment_in_bytes-1);
asm_assert_eq("resize_frame: unaligned", 0x204);
#endif
// tmp <- *(SP)
ld(tmp, _abi(callers_sp), R1_SP);
// addr <- SP + offset;
// *(addr) <- tmp;
// SP <- addr
stdux(tmp, R1_SP, offset);
}
void MacroAssembler::resize_frame(int offset, Register tmp) {
assert(is_simm(offset, 16), "too big an offset");
assert_different_registers(tmp, R1_SP);
assert((offset & (frame::alignment_in_bytes-1))==0, "resize_frame: unaligned");
// tmp <- *(SP)
ld(tmp, _abi(callers_sp), R1_SP);
// addr <- SP + offset;
// *(addr) <- tmp;
// SP <- addr
stdu(tmp, offset, R1_SP);
}
void MacroAssembler::resize_frame_absolute(Register addr, Register tmp1, Register tmp2) {
// (addr == tmp1) || (addr == tmp2) is allowed here!
assert(tmp1 != tmp2, "must be distinct");
// compute offset w.r.t. current stack pointer
// tmp_1 <- addr - SP (!)
subf(tmp1, R1_SP, addr);
// atomically update SP keeping back link.
resize_frame(tmp1/* offset */, tmp2/* tmp */);
}
void MacroAssembler::push_frame(Register bytes, Register tmp) {
#ifdef ASSERT
assert(bytes != R0, "r0 not allowed here");
andi_(R0, bytes, frame::alignment_in_bytes-1);
asm_assert_eq("push_frame(Reg, Reg): unaligned", 0x203);
#endif
neg(tmp, bytes);
stdux(R1_SP, R1_SP, tmp);
}
// Push a frame of size `bytes'.
void MacroAssembler::push_frame(unsigned int bytes, Register tmp) {
long offset = align_addr(bytes, frame::alignment_in_bytes);
if (is_simm(-offset, 16)) {
stdu(R1_SP, -offset, R1_SP);
} else {
load_const(tmp, -offset);
stdux(R1_SP, R1_SP, tmp);
}
}
// Push a frame of size `bytes' plus abi112 on top.
void MacroAssembler::push_frame_abi112(unsigned int bytes, Register tmp) {
push_frame(bytes + frame::abi_112_size, tmp);
}
// Setup up a new C frame with a spill area for non-volatile GPRs and
// additional space for local variables.
void MacroAssembler::push_frame_abi112_nonvolatiles(unsigned int bytes,
Register tmp) {
push_frame(bytes + frame::abi_112_size + frame::spill_nonvolatiles_size, tmp);
}
// Pop current C frame.
void MacroAssembler::pop_frame() {
ld(R1_SP, _abi(callers_sp), R1_SP);
}
// Generic version of a call to C function via a function descriptor
// with variable support for C calling conventions (TOC, ENV, etc.).
// Updates and returns _last_calls_return_pc.
address MacroAssembler::branch_to(Register function_descriptor, bool and_link, bool save_toc_before_call,
bool restore_toc_after_call, bool load_toc_of_callee, bool load_env_of_callee) {
// we emit standard ptrgl glue code here
assert((function_descriptor != R0), "function_descriptor cannot be R0");
// retrieve necessary entries from the function descriptor
ld(R0, in_bytes(FunctionDescriptor::entry_offset()), function_descriptor);
mtctr(R0);
if (load_toc_of_callee) {
ld(R2_TOC, in_bytes(FunctionDescriptor::toc_offset()), function_descriptor);
}
if (load_env_of_callee) {
ld(R11, in_bytes(FunctionDescriptor::env_offset()), function_descriptor);
} else if (load_toc_of_callee) {
li(R11, 0);
}
// do a call or a branch
if (and_link) {
bctrl();
} else {
bctr();
}
_last_calls_return_pc = pc();
return _last_calls_return_pc;
}
// Call a C function via a function descriptor and use full C calling
// conventions.
// We don't use the TOC in generated code, so there is no need to save
// and restore its value.
address MacroAssembler::call_c(Register fd) {
return branch_to(fd, /*and_link=*/true,
/*save toc=*/false,
/*restore toc=*/false,
/*load toc=*/true,
/*load env=*/true);
}
address MacroAssembler::call_c(const FunctionDescriptor* fd, relocInfo::relocType rt) {
if (rt != relocInfo::none) {
// this call needs to be relocatable
if (!ReoptimizeCallSequences
|| (rt != relocInfo::runtime_call_type && rt != relocInfo::none)
|| fd == NULL // support code-size estimation
|| !fd->is_friend_function()
|| fd->entry() == NULL) {
// it's not a friend function as defined by class FunctionDescriptor,
// so do a full call-c here.
load_const(R11, (address)fd, R0);
bool has_env = (fd != NULL && fd->env() != NULL);
return branch_to(R11, /*and_link=*/true,
/*save toc=*/false,
/*restore toc=*/false,
/*load toc=*/true,
/*load env=*/has_env);
} else {
// It's a friend function. Load the entry point and don't care about
// toc and env. Use an optimizable call instruction, but ensure the
// same code-size as in the case of a non-friend function.
nop();
nop();
nop();
bl64_patchable(fd->entry(), rt);
_last_calls_return_pc = pc();
return _last_calls_return_pc;
}
} else {
// This call does not need to be relocatable, do more aggressive
// optimizations.
if (!ReoptimizeCallSequences
|| !fd->is_friend_function()) {
// It's not a friend function as defined by class FunctionDescriptor,
// so do a full call-c here.
load_const(R11, (address)fd, R0);
return branch_to(R11, /*and_link=*/true,
/*save toc=*/false,
/*restore toc=*/false,
/*load toc=*/true,
/*load env=*/true);
} else {
// it's a friend function, load the entry point and don't care about
// toc and env.
address dest = fd->entry();
if (is_within_range_of_b(dest, pc())) {
bl(dest);
} else {
bl64_patchable(dest, rt);
}
_last_calls_return_pc = pc();
return _last_calls_return_pc;
}
}
}
// Call a C function. All constants needed reside in TOC.
//
// Read the address to call from the TOC.
// Read env from TOC, if fd specifies an env.
// Read new TOC from TOC.
address MacroAssembler::call_c_using_toc(const FunctionDescriptor* fd,
relocInfo::relocType rt, Register toc) {
if (!ReoptimizeCallSequences
|| (rt != relocInfo::runtime_call_type && rt != relocInfo::none)
|| !fd->is_friend_function()) {
// It's not a friend function as defined by class FunctionDescriptor,
// so do a full call-c here.
assert(fd->entry() != NULL, "function must be linked");
AddressLiteral fd_entry(fd->entry());
load_const_from_method_toc(R11, fd_entry, toc);
mtctr(R11);
if (fd->env() == NULL) {
li(R11, 0);
nop();
} else {
AddressLiteral fd_env(fd->env());
load_const_from_method_toc(R11, fd_env, toc);
}
AddressLiteral fd_toc(fd->toc());
load_toc_from_toc(R2_TOC, fd_toc, toc);
// R2_TOC is killed.
bctrl();
_last_calls_return_pc = pc();
} else {
// It's a friend function, load the entry point and don't care about
// toc and env. Use an optimizable call instruction, but ensure the
// same code-size as in the case of a non-friend function.
nop();
bl64_patchable(fd->entry(), rt);
_last_calls_return_pc = pc();
}
return _last_calls_return_pc;
}
void MacroAssembler::call_VM_base(Register oop_result,
Register last_java_sp,
address entry_point,
bool check_exceptions) {
BLOCK_COMMENT("call_VM {");
// Determine last_java_sp register.
if (!last_java_sp->is_valid()) {
last_java_sp = R1_SP;
}
set_top_ijava_frame_at_SP_as_last_Java_frame(last_java_sp, R11_scratch1);
// ARG1 must hold thread address.
mr(R3_ARG1, R16_thread);
address return_pc = call_c((FunctionDescriptor*)entry_point, relocInfo::none);
reset_last_Java_frame();
// Check for pending exceptions.
if (check_exceptions) {
// We don't check for exceptions here.
ShouldNotReachHere();
}
// Get oop result if there is one and reset the value in the thread.
if (oop_result->is_valid()) {
get_vm_result(oop_result);
}
_last_calls_return_pc = return_pc;
BLOCK_COMMENT("} call_VM");
}
void MacroAssembler::call_VM_leaf_base(address entry_point) {
BLOCK_COMMENT("call_VM_leaf {");
call_c(CAST_FROM_FN_PTR(FunctionDescriptor*, entry_point), relocInfo::none);
BLOCK_COMMENT("} call_VM_leaf");
}
void MacroAssembler::call_VM(Register oop_result, address entry_point, bool check_exceptions) {
call_VM_base(oop_result, noreg, entry_point, check_exceptions);
}
void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1,
bool check_exceptions) {
// R3_ARG1 is reserved for the thread.
mr_if_needed(R4_ARG2, arg_1);
call_VM(oop_result, entry_point, check_exceptions);
}
void MacroAssembler::call_VM(Register oop_result, address entry_point, Register arg_1, Register arg_2,
bool check_exceptions) {
// R3_ARG1 is reserved for the thread
mr_if_needed(R4_ARG2, arg_1);
assert(arg_2 != R4_ARG2, "smashed argument");
mr_if_needed(R5_ARG3, arg_2);
call_VM(oop_result, entry_point, check_exceptions);
}
void MacroAssembler::call_VM_leaf(address entry_point) {
call_VM_leaf_base(entry_point);
}
void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1) {
mr_if_needed(R3_ARG1, arg_1);
call_VM_leaf(entry_point);
}
void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1, Register arg_2) {
mr_if_needed(R3_ARG1, arg_1);
assert(arg_2 != R3_ARG1, "smashed argument");
mr_if_needed(R4_ARG2, arg_2);
call_VM_leaf(entry_point);
}
void MacroAssembler::call_VM_leaf(address entry_point, Register arg_1, Register arg_2, Register arg_3) {
mr_if_needed(R3_ARG1, arg_1);
assert(arg_2 != R3_ARG1, "smashed argument");
mr_if_needed(R4_ARG2, arg_2);
assert(arg_3 != R3_ARG1 && arg_3 != R4_ARG2, "smashed argument");
mr_if_needed(R5_ARG3, arg_3);
call_VM_leaf(entry_point);
}
// Check whether instruction is a read access to the polling page
// which was emitted by load_from_polling_page(..).
bool MacroAssembler::is_load_from_polling_page(int instruction, void* ucontext,
address* polling_address_ptr) {
if (!is_ld(instruction))
return false; // It's not a ld. Fail.
int rt = inv_rt_field(instruction);
int ra = inv_ra_field(instruction);
int ds = inv_ds_field(instruction);
if (!(ds == 0 && ra != 0 && rt == 0)) {
return false; // It's not a ld(r0, X, ra). Fail.
}
if (!ucontext) {
// Set polling address.
if (polling_address_ptr != NULL) {
*polling_address_ptr = NULL;
}
return true; // No ucontext given. Can't check value of ra. Assume true.
}
#ifdef LINUX
// Ucontext given. Check that register ra contains the address of
// the safepoing polling page.
ucontext_t* uc = (ucontext_t*) ucontext;
// Set polling address.
address addr = (address)uc->uc_mcontext.regs->gpr[ra] + (ssize_t)ds;
if (polling_address_ptr != NULL) {
*polling_address_ptr = addr;
}
return os::is_poll_address(addr);
#else
// Not on Linux, ucontext must be NULL.
ShouldNotReachHere();
return false;
#endif
}
bool MacroAssembler::is_memory_serialization(int instruction, JavaThread* thread, void* ucontext) {
#ifdef LINUX
ucontext_t* uc = (ucontext_t*) ucontext;
if (is_stwx(instruction) || is_stwux(instruction)) {
int ra = inv_ra_field(instruction);
int rb = inv_rb_field(instruction);
// look up content of ra and rb in ucontext
address ra_val=(address)uc->uc_mcontext.regs->gpr[ra];
long rb_val=(long)uc->uc_mcontext.regs->gpr[rb];
return os::is_memory_serialize_page(thread, ra_val+rb_val);
} else if (is_stw(instruction) || is_stwu(instruction)) {
int ra = inv_ra_field(instruction);
int d1 = inv_d1_field(instruction);
// look up content of ra in ucontext
address ra_val=(address)uc->uc_mcontext.regs->gpr[ra];
return os::is_memory_serialize_page(thread, ra_val+d1);
} else {
return false;
}
#else
// workaround not needed on !LINUX :-)
ShouldNotCallThis();
return false;
#endif
}
void MacroAssembler::bang_stack_with_offset(int offset) {
// When increasing the stack, the old stack pointer will be written
// to the new top of stack according to the PPC64 abi.
// Therefore, stack banging is not necessary when increasing
// the stack by <= os::vm_page_size() bytes.
// When increasing the stack by a larger amount, this method is
// called repeatedly to bang the intermediate pages.
// Stack grows down, caller passes positive offset.
assert(offset > 0, "must bang with positive offset");
long stdoffset = -offset;
if (is_simm(stdoffset, 16)) {
// Signed 16 bit offset, a simple std is ok.
if (UseLoadInstructionsForStackBangingPPC64) {
ld(R0, (int)(signed short)stdoffset, R1_SP);
} else {
std(R0,(int)(signed short)stdoffset, R1_SP);
}
} else if (is_simm(stdoffset, 31)) {
const int hi = MacroAssembler::largeoffset_si16_si16_hi(stdoffset);
const int lo = MacroAssembler::largeoffset_si16_si16_lo(stdoffset);
Register tmp = R11;
addis(tmp, R1_SP, hi);
if (UseLoadInstructionsForStackBangingPPC64) {
ld(R0, lo, tmp);
} else {
std(R0, lo, tmp);
}
} else {
ShouldNotReachHere();
}
}
// If instruction is a stack bang of the form
// std R0, x(Ry), (see bang_stack_with_offset())
// stdu R1_SP, x(R1_SP), (see push_frame(), resize_frame())
// or stdux R1_SP, Rx, R1_SP (see push_frame(), resize_frame())
// return the banged address. Otherwise, return 0.
address MacroAssembler::get_stack_bang_address(int instruction, void *ucontext) {
#ifdef LINUX
ucontext_t* uc = (ucontext_t*) ucontext;
int rs = inv_rs_field(instruction);
int ra = inv_ra_field(instruction);
if ( (is_ld(instruction) && rs == 0 && UseLoadInstructionsForStackBangingPPC64)
|| (is_std(instruction) && rs == 0 && !UseLoadInstructionsForStackBangingPPC64)
|| (is_stdu(instruction) && rs == 1)) {
int ds = inv_ds_field(instruction);
// return banged address
return ds+(address)uc->uc_mcontext.regs->gpr[ra];
} else if (is_stdux(instruction) && rs == 1) {
int rb = inv_rb_field(instruction);
address sp = (address)uc->uc_mcontext.regs->gpr[1];
long rb_val = (long)uc->uc_mcontext.regs->gpr[rb];
return ra != 1 || rb_val >= 0 ? NULL // not a stack bang
: sp + rb_val; // banged address
}
return NULL; // not a stack bang
#else
// workaround not needed on !LINUX :-)
ShouldNotCallThis();
return NULL;
#endif
}
// CmpxchgX sets condition register to cmpX(current, compare).
void MacroAssembler::cmpxchgw(ConditionRegister flag, Register dest_current_value,
Register compare_value, Register exchange_value,
Register addr_base, int semantics, bool cmpxchgx_hint,
Register int_flag_success, bool contention_hint) {
Label retry;
Label failed;
Label done;
// Save one branch if result is returned via register and
// result register is different from the other ones.
bool use_result_reg = (int_flag_success != noreg);
bool preset_result_reg = (int_flag_success != dest_current_value && int_flag_success != compare_value &&
int_flag_success != exchange_value && int_flag_success != addr_base);
// release/fence semantics
if (semantics & MemBarRel) {
release();
}
if (use_result_reg && preset_result_reg) {
li(int_flag_success, 0); // preset (assume cas failed)
}
// Add simple guard in order to reduce risk of starving under high contention (recommended by IBM).
if (contention_hint) { // Don't try to reserve if cmp fails.
lwz(dest_current_value, 0, addr_base);
cmpw(flag, dest_current_value, compare_value);
bne(flag, failed);
}
// atomic emulation loop
bind(retry);
lwarx(dest_current_value, addr_base, cmpxchgx_hint);
cmpw(flag, dest_current_value, compare_value);
if (UseStaticBranchPredictionInCompareAndSwapPPC64) {
bne_predict_not_taken(flag, failed);
} else {
bne( flag, failed);
}
// branch to done => (flag == ne), (dest_current_value != compare_value)
// fall through => (flag == eq), (dest_current_value == compare_value)
stwcx_(exchange_value, addr_base);
if (UseStaticBranchPredictionInCompareAndSwapPPC64) {
bne_predict_not_taken(CCR0, retry); // StXcx_ sets CCR0.
} else {
bne( CCR0, retry); // StXcx_ sets CCR0.
}
// fall through => (flag == eq), (dest_current_value == compare_value), (swapped)
// Result in register (must do this at the end because int_flag_success can be the
// same register as one above).
if (use_result_reg) {
li(int_flag_success, 1);
}
if (semantics & MemBarFenceAfter) {
fence();
} else if (semantics & MemBarAcq) {
isync();
}
if (use_result_reg && !preset_result_reg) {
b(done);
}
bind(failed);
if (use_result_reg && !preset_result_reg) {
li(int_flag_success, 0);
}
bind(done);
// (flag == ne) => (dest_current_value != compare_value), (!swapped)
// (flag == eq) => (dest_current_value == compare_value), ( swapped)
}
// Preforms atomic compare exchange:
// if (compare_value == *addr_base)
// *addr_base = exchange_value
// int_flag_success = 1;
// else
// int_flag_success = 0;
//
// ConditionRegister flag = cmp(compare_value, *addr_base)
// Register dest_current_value = *addr_base
// Register compare_value Used to compare with value in memory
// Register exchange_value Written to memory if compare_value == *addr_base
// Register addr_base The memory location to compareXChange
// Register int_flag_success Set to 1 if exchange_value was written to *addr_base
//
// To avoid the costly compare exchange the value is tested beforehand.
// Several special cases exist to avoid that unnecessary information is generated.
//
void MacroAssembler::cmpxchgd(ConditionRegister flag,
Register dest_current_value, Register compare_value, Register exchange_value,
Register addr_base, int semantics, bool cmpxchgx_hint,
Register int_flag_success, Label* failed_ext, bool contention_hint) {
Label retry;
Label failed_int;
Label& failed = (failed_ext != NULL) ? *failed_ext : failed_int;
Label done;
// Save one branch if result is returned via register and result register is different from the other ones.
bool use_result_reg = (int_flag_success!=noreg);
bool preset_result_reg = (int_flag_success!=dest_current_value && int_flag_success!=compare_value &&
int_flag_success!=exchange_value && int_flag_success!=addr_base);
assert(int_flag_success == noreg || failed_ext == NULL, "cannot have both");
// release/fence semantics
if (semantics & MemBarRel) {
release();
}
if (use_result_reg && preset_result_reg) {
li(int_flag_success, 0); // preset (assume cas failed)
}
// Add simple guard in order to reduce risk of starving under high contention (recommended by IBM).
if (contention_hint) { // Don't try to reserve if cmp fails.
ld(dest_current_value, 0, addr_base);
cmpd(flag, dest_current_value, compare_value);
bne(flag, failed);
}
// atomic emulation loop
bind(retry);
ldarx(dest_current_value, addr_base, cmpxchgx_hint);
cmpd(flag, dest_current_value, compare_value);
if (UseStaticBranchPredictionInCompareAndSwapPPC64) {
bne_predict_not_taken(flag, failed);
} else {
bne( flag, failed);
}
stdcx_(exchange_value, addr_base);
if (UseStaticBranchPredictionInCompareAndSwapPPC64) {
bne_predict_not_taken(CCR0, retry); // stXcx_ sets CCR0
} else {
bne( CCR0, retry); // stXcx_ sets CCR0
}
// result in register (must do this at the end because int_flag_success can be the same register as one above)
if (use_result_reg) {
li(int_flag_success, 1);
}
// POWER6 doesn't need isync in CAS.
// Always emit isync to be on the safe side.
if (semantics & MemBarFenceAfter) {
fence();
} else if (semantics & MemBarAcq) {
isync();
}
if (use_result_reg && !preset_result_reg) {
b(done);
}
bind(failed_int);
if (use_result_reg && !preset_result_reg) {
li(int_flag_success, 0);
}
bind(done);
// (flag == ne) => (dest_current_value != compare_value), (!swapped)
// (flag == eq) => (dest_current_value == compare_value), ( swapped)
}
// Look up the method for a megamorphic invokeinterface call.
// The target method is determined by <intf_klass, itable_index>.
// The receiver klass is in recv_klass.
// 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 recv_klass,
Register intf_klass,
RegisterOrConstant itable_index,
Register method_result,
Register scan_temp,
Register sethi_temp,
Label& L_no_such_interface) {
assert_different_registers(recv_klass, intf_klass, method_result, scan_temp);
assert(itable_index.is_constant() || itable_index.as_register() == method_result,
"caller must use same register for non-constant itable index as for method");
// Compute start of first itableOffsetEntry (which is at the end of the vtable).
int vtable_base = InstanceKlass::vtable_start_offset() * wordSize;
int itentry_off = itableMethodEntry::method_offset_in_bytes();
int logMEsize = exact_log2(itableMethodEntry::size() * wordSize);
int scan_step = itableOffsetEntry::size() * wordSize;
int log_vte_size= exact_log2(vtableEntry::size() * wordSize);
lwz(scan_temp, InstanceKlass::vtable_length_offset() * wordSize, recv_klass);
// %%% We should store the aligned, prescaled offset in the klassoop.
// Then the next several instructions would fold away.
sldi(scan_temp, scan_temp, log_vte_size);
addi(scan_temp, scan_temp, vtable_base);
add(scan_temp, recv_klass, scan_temp);
// Adjust recv_klass by scaled itable_index, so we can free itable_index.
if (itable_index.is_register()) {
Register itable_offset = itable_index.as_register();
sldi(itable_offset, itable_offset, logMEsize);
if (itentry_off) addi(itable_offset, itable_offset, itentry_off);
add(recv_klass, itable_offset, recv_klass);
} else {
long itable_offset = (long)itable_index.as_constant();
load_const_optimized(sethi_temp, (itable_offset<<logMEsize)+itentry_off); // static address, no relocation
add(recv_klass, sethi_temp, recv_klass);
}
// for (scan = klass->itable(); scan->interface() != NULL; scan += scan_step) {
// if (scan->interface() == intf) {
// result = (klass + scan->offset() + itable_index);
// }
// }
Label search, found_method;
for (int peel = 1; peel >= 0; peel--) {
// %%%% Could load both offset and interface in one ldx, if they were
// in the opposite order. This would save a load.
ld(method_result, itableOffsetEntry::interface_offset_in_bytes(), scan_temp);
// Check that this entry is non-null. A null entry means that
// the receiver class doesn't implement the interface, and wasn't the
// same as when the caller was compiled.
cmpd(CCR0, method_result, intf_klass);
if (peel) {
beq(CCR0, found_method);
} else {
bne(CCR0, search);
// (invert the test to fall through to found_method...)
}
if (!peel) break;
bind(search);
cmpdi(CCR0, method_result, 0);
beq(CCR0, L_no_such_interface);
addi(scan_temp, scan_temp, scan_step);
}
bind(found_method);
// Got a hit.
int ito_offset = itableOffsetEntry::offset_offset_in_bytes();
lwz(scan_temp, ito_offset, scan_temp);
ldx(method_result, scan_temp, recv_klass);
}
// virtual method calling
void MacroAssembler::lookup_virtual_method(Register recv_klass,
RegisterOrConstant vtable_index,
Register method_result) {
assert_different_registers(recv_klass, method_result, vtable_index.register_or_noreg());
const int base = InstanceKlass::vtable_start_offset() * wordSize;
assert(vtableEntry::size() * wordSize == wordSize, "adjust the scaling in the code below");
if (vtable_index.is_register()) {
sldi(vtable_index.as_register(), vtable_index.as_register(), LogBytesPerWord);
add(recv_klass, vtable_index.as_register(), recv_klass);
} else {
addi(recv_klass, recv_klass, vtable_index.as_constant() << LogBytesPerWord);
}
ld(R19_method, base + vtableEntry::method_offset_in_bytes(), recv_klass);
}
/////////////////////////////////////////// subtype checking ////////////////////////////////////////////
void MacroAssembler::check_klass_subtype_fast_path(Register sub_klass,
Register super_klass,
Register temp1_reg,
Register temp2_reg,
Label& L_success,
Label& L_failure) {
const Register check_cache_offset = temp1_reg;
const Register cached_super = temp2_reg;
assert_different_registers(sub_klass, super_klass, check_cache_offset, cached_super);
int sco_offset = in_bytes(Klass::super_check_offset_offset());
int sc_offset = in_bytes(Klass::secondary_super_cache_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.
cmpd(CCR0, sub_klass, super_klass);
beq(CCR0, L_success);
// Check the supertype display:
lwz(check_cache_offset, sco_offset, super_klass);
// The loaded value is the offset from KlassOopDesc.
ldx(cached_super, check_cache_offset, sub_klass);
cmpd(CCR0, cached_super, super_klass);
beq(CCR0, L_success);
// 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).
cmpwi(CCR0, check_cache_offset, sc_offset);
bne(CCR0, L_failure);
// bind(slow_path); // fallthru
}
void MacroAssembler::check_klass_subtype_slow_path(Register sub_klass,
Register super_klass,
Register temp1_reg,
Register temp2_reg,
Label* L_success,
Register result_reg) {
const Register array_ptr = temp1_reg; // current value from cache array
const Register temp = temp2_reg;
assert_different_registers(sub_klass, super_klass, array_ptr, temp);
int source_offset = in_bytes(Klass::secondary_supers_offset());
int target_offset = in_bytes(Klass::secondary_super_cache_offset());
int length_offset = Array<Klass*>::length_offset_in_bytes();
int base_offset = Array<Klass*>::base_offset_in_bytes();
Label hit, loop, failure, fallthru;
ld(array_ptr, source_offset, sub_klass);
//assert(4 == arrayOopDesc::length_length_in_bytes(), "precondition violated.");
lwz(temp, length_offset, array_ptr);
cmpwi(CCR0, temp, 0);
beq(CCR0, result_reg!=noreg ? failure : fallthru); // length 0
mtctr(temp); // load ctr
bind(loop);
// Oops in table are NO MORE compressed.
ld(temp, base_offset, array_ptr);
cmpd(CCR0, temp, super_klass);
beq(CCR0, hit);
addi(array_ptr, array_ptr, BytesPerWord);
bdnz(loop);
bind(failure);
if (result_reg!=noreg) li(result_reg, 1); // load non-zero result (indicates a miss)
b(fallthru);
bind(hit);
std(super_klass, target_offset, sub_klass); // save result to cache
if (result_reg != noreg) li(result_reg, 0); // load zero result (indicates a hit)
if (L_success != NULL) b(*L_success);
bind(fallthru);
}
// Try fast path, then go to slow one if not successful
void MacroAssembler::check_klass_subtype(Register sub_klass,
Register super_klass,
Register temp1_reg,
Register temp2_reg,
Label& L_success) {
Label L_failure;
check_klass_subtype_fast_path(sub_klass, super_klass, temp1_reg, temp2_reg, L_success, L_failure);
check_klass_subtype_slow_path(sub_klass, super_klass, temp1_reg, temp2_reg, &L_success);
bind(L_failure); // Fallthru if not successful.
}
void MacroAssembler::check_method_handle_type(Register mtype_reg, Register mh_reg,
Register temp_reg,
Label& wrong_method_type) {
assert_different_registers(mtype_reg, mh_reg, temp_reg);
// Compare method type against that of the receiver.
load_heap_oop_not_null(temp_reg, delayed_value(java_lang_invoke_MethodHandle::type_offset_in_bytes, temp_reg), mh_reg);
cmpd(CCR0, temp_reg, mtype_reg);
bne(CCR0, wrong_method_type);
}
RegisterOrConstant MacroAssembler::argument_offset(RegisterOrConstant arg_slot,
Register temp_reg,
int extra_slot_offset) {
// cf. TemplateTable::prepare_invoke(), if (load_receiver).
int stackElementSize = Interpreter::stackElementSize;
int offset = extra_slot_offset * stackElementSize;
if (arg_slot.is_constant()) {
offset += arg_slot.as_constant() * stackElementSize;
return offset;
} else {
assert(temp_reg != noreg, "must specify");
sldi(temp_reg, arg_slot.as_register(), exact_log2(stackElementSize));
if (offset != 0)
addi(temp_reg, temp_reg, offset);
return temp_reg;
}
}
void MacroAssembler::biased_locking_enter(ConditionRegister cr_reg, Register obj_reg,
Register mark_reg, Register temp_reg,
Register temp2_reg, Label& done, Label* slow_case) {
assert(UseBiasedLocking, "why call this otherwise?");
#ifdef ASSERT
assert_different_registers(obj_reg, mark_reg, temp_reg, temp2_reg);
#endif
Label cas_label;
// Branch to done if fast path fails and no slow_case provided.
Label *slow_case_int = (slow_case != NULL) ? slow_case : &done;
// 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
assert(markOopDesc::age_shift == markOopDesc::lock_bits + markOopDesc::biased_lock_bits,
"biased locking makes assumptions about bit layout");
if (PrintBiasedLockingStatistics) {
load_const(temp_reg, (address) BiasedLocking::total_entry_count_addr(), temp2_reg);
lwz(temp2_reg, 0, temp_reg);
addi(temp2_reg, temp2_reg, 1);
stw(temp2_reg, 0, temp_reg);
}
andi(temp_reg, mark_reg, markOopDesc::biased_lock_mask_in_place);
cmpwi(cr_reg, temp_reg, markOopDesc::biased_lock_pattern);
bne(cr_reg, cas_label);
load_klass_with_trap_null_check(temp_reg, obj_reg);
load_const_optimized(temp2_reg, ~((int) markOopDesc::age_mask_in_place));
ld(temp_reg, in_bytes(Klass::prototype_header_offset()), temp_reg);
orr(temp_reg, R16_thread, temp_reg);
xorr(temp_reg, mark_reg, temp_reg);
andr(temp_reg, temp_reg, temp2_reg);
cmpdi(cr_reg, temp_reg, 0);
if (PrintBiasedLockingStatistics) {
Label l;
bne(cr_reg, l);
load_const(mark_reg, (address) BiasedLocking::biased_lock_entry_count_addr());
lwz(temp2_reg, 0, mark_reg);
addi(temp2_reg, temp2_reg, 1);
stw(temp2_reg, 0, mark_reg);
// restore mark_reg
ld(mark_reg, oopDesc::mark_offset_in_bytes(), obj_reg);
bind(l);
}
beq(cr_reg, done);
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.
andi(temp2_reg, temp_reg, markOopDesc::biased_lock_mask_in_place);
cmpwi(cr_reg, temp2_reg, 0);
bne(cr_reg, try_revoke_bias);
// 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.
int shift_amount = 64 - markOopDesc::epoch_shift;
// rotate epoch bits to right (little) end and set other bits to 0
// [ big part | epoch | little part ] -> [ 0..0 | epoch ]
rldicl_(temp2_reg, temp_reg, shift_amount, 64 - markOopDesc::epoch_bits);
// branch if epoch bits are != 0, i.e. they differ, because the epoch has been incremented
bne(CCR0, try_rebias);
// 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.
andi(mark_reg, mark_reg, (markOopDesc::biased_lock_mask_in_place |
markOopDesc::age_mask_in_place |
markOopDesc::epoch_mask_in_place));
orr(temp_reg, R16_thread, mark_reg);
assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
// CmpxchgX sets cr_reg to cmpX(temp2_reg, mark_reg).
fence(); // TODO: replace by MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq ?
cmpxchgd(/*flag=*/cr_reg, /*current_value=*/temp2_reg,
/*compare_value=*/mark_reg, /*exchange_value=*/temp_reg,
/*where=*/obj_reg,
MacroAssembler::MemBarAcq,
MacroAssembler::cmpxchgx_hint_acquire_lock(),
noreg, slow_case_int); // bail out if failed
// 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.
if (PrintBiasedLockingStatistics) {
load_const(temp_reg, (address) BiasedLocking::anonymously_biased_lock_entry_count_addr(), temp2_reg);
lwz(temp2_reg, 0, temp_reg);
addi(temp2_reg, temp2_reg, 1);
stw(temp2_reg, 0, temp_reg);
}
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.
andi(temp_reg, mark_reg, markOopDesc::age_mask_in_place);
orr(temp_reg, R16_thread, temp_reg);
load_klass_with_trap_null_check(temp2_reg, obj_reg);
ld(temp2_reg, in_bytes(Klass::prototype_header_offset()), temp2_reg);
orr(temp_reg, temp_reg, temp2_reg);
assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
// CmpxchgX sets cr_reg to cmpX(temp2_reg, mark_reg).
fence(); // TODO: replace by MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq ?
cmpxchgd(/*flag=*/cr_reg, /*current_value=*/temp2_reg,
/*compare_value=*/mark_reg, /*exchange_value=*/temp_reg,
/*where=*/obj_reg,
MacroAssembler::MemBarAcq,
MacroAssembler::cmpxchgx_hint_acquire_lock(),
noreg, slow_case_int); // bail out if failed
// 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.
if (PrintBiasedLockingStatistics) {
load_const(temp_reg, (address) BiasedLocking::rebiased_lock_entry_count_addr(), temp2_reg);
lwz(temp2_reg, 0, temp_reg);
addi(temp2_reg, temp2_reg, 1);
stw(temp2_reg, 0, temp_reg);
}
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.
load_klass_with_trap_null_check(temp_reg, obj_reg);
ld(temp_reg, in_bytes(Klass::prototype_header_offset()), temp_reg);
andi(temp2_reg, mark_reg, markOopDesc::age_mask_in_place);
orr(temp_reg, temp_reg, temp2_reg);
assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
// CmpxchgX sets cr_reg to cmpX(temp2_reg, mark_reg).
fence(); // TODO: replace by MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq ?
cmpxchgd(/*flag=*/cr_reg, /*current_value=*/temp2_reg,
/*compare_value=*/mark_reg, /*exchange_value=*/temp_reg,
/*where=*/obj_reg,
MacroAssembler::MemBarAcq,
MacroAssembler::cmpxchgx_hint_acquire_lock());
// reload markOop in mark_reg before continuing with lightweight locking
ld(mark_reg, oopDesc::mark_offset_in_bytes(), obj_reg);
// 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.
if (PrintBiasedLockingStatistics) {
Label l;
bne(cr_reg, l);
load_const(temp_reg, (address) BiasedLocking::revoked_lock_entry_count_addr(), temp2_reg);
lwz(temp2_reg, 0, temp_reg);
addi(temp2_reg, temp2_reg, 1);
stw(temp2_reg, 0, temp_reg);
bind(l);
}
bind(cas_label);
}
void MacroAssembler::biased_locking_exit (ConditionRegister cr_reg, Register mark_addr, Register temp_reg, Label& done) {
// 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.
ld(temp_reg, 0, mark_addr);
andi(temp_reg, temp_reg, markOopDesc::biased_lock_mask_in_place);
cmpwi(cr_reg, temp_reg, markOopDesc::biased_lock_pattern);
beq(cr_reg, done);
}
// "The box" is the space on the stack where we copy the object mark.
void MacroAssembler::compiler_fast_lock_object(ConditionRegister flag, Register oop, Register box,
Register temp, Register displaced_header, Register current_header) {
assert_different_registers(oop, box, temp, displaced_header, current_header);
assert(flag != CCR0, "bad condition register");
Label cont;
Label object_has_monitor;
Label cas_failed;
// Load markOop from object into displaced_header.
ld(displaced_header, oopDesc::mark_offset_in_bytes(), oop);
// Always do locking in runtime.
if (EmitSync & 0x01) {
cmpdi(flag, oop, 0); // Oop can't be 0 here => always false.
return;
}
if (UseBiasedLocking) {
biased_locking_enter(flag, oop, displaced_header, temp, current_header, cont);
}
// Handle existing monitor.
if ((EmitSync & 0x02) == 0) {
// The object has an existing monitor iff (mark & monitor_value) != 0.
andi_(temp, displaced_header, markOopDesc::monitor_value);
bne(CCR0, object_has_monitor);
}
// Set displaced_header to be (markOop of object | UNLOCK_VALUE).
ori(displaced_header, displaced_header, markOopDesc::unlocked_value);
// Load Compare Value application register.
// Initialize the box. (Must happen before we update the object mark!)
std(displaced_header, BasicLock::displaced_header_offset_in_bytes(), box);
// Must fence, otherwise, preceding store(s) may float below cmpxchg.
// Compare object markOop with mark and if equal exchange scratch1 with object markOop.
// CmpxchgX sets cr_reg to cmpX(current, displaced).
cmpxchgd(/*flag=*/flag,
/*current_value=*/current_header,
/*compare_value=*/displaced_header,
/*exchange_value=*/box,
/*where=*/oop,
MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq,
MacroAssembler::cmpxchgx_hint_acquire_lock(),
noreg,
&cas_failed);
assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
// If the compare-and-exchange succeeded, then we found an unlocked
// object and we have now locked it.
b(cont);
bind(cas_failed);
// We did not see an unlocked object so try the fast recursive case.
// Check if the owner is self by comparing the value in the markOop of object
// (current_header) with the stack pointer.
sub(current_header, current_header, R1_SP);
load_const_optimized(temp, (address) (~(os::vm_page_size()-1) |
markOopDesc::lock_mask_in_place));
and_(R0/*==0?*/, current_header, temp);
// If condition is true we are cont and hence we can store 0 as the
// displaced header in the box, which indicates that it is a recursive lock.
mcrf(flag,CCR0);
std(R0/*==0, perhaps*/, BasicLock::displaced_header_offset_in_bytes(), box);
// Handle existing monitor.
if ((EmitSync & 0x02) == 0) {
b(cont);
bind(object_has_monitor);
// The object's monitor m is unlocked iff m->owner == NULL,
// otherwise m->owner may contain a thread or a stack address.
//
// Try to CAS m->owner from NULL to current thread.
addi(temp, displaced_header, ObjectMonitor::owner_offset_in_bytes()-markOopDesc::monitor_value);
li(displaced_header, 0);
// CmpxchgX sets flag to cmpX(current, displaced).
cmpxchgd(/*flag=*/flag,
/*current_value=*/current_header,
/*compare_value=*/displaced_header,
/*exchange_value=*/R16_thread,
/*where=*/temp,
MacroAssembler::MemBarRel | MacroAssembler::MemBarAcq,
MacroAssembler::cmpxchgx_hint_acquire_lock());
// Store a non-null value into the box.
std(box, BasicLock::displaced_header_offset_in_bytes(), box);
# ifdef ASSERT
bne(flag, cont);
// We have acquired the monitor, check some invariants.
addi(/*monitor=*/temp, temp, -ObjectMonitor::owner_offset_in_bytes());
// Invariant 1: _recursions should be 0.
//assert(ObjectMonitor::recursions_size_in_bytes() == 8, "unexpected size");
asm_assert_mem8_is_zero(ObjectMonitor::recursions_offset_in_bytes(), temp,
"monitor->_recursions should be 0", -1);
// Invariant 2: OwnerIsThread shouldn't be 0.
//assert(ObjectMonitor::OwnerIsThread_size_in_bytes() == 4, "unexpected size");
//asm_assert_mem4_isnot_zero(ObjectMonitor::OwnerIsThread_offset_in_bytes(), temp,
// "monitor->OwnerIsThread shouldn't be 0", -1);
# endif
}
bind(cont);
// flag == EQ indicates success
// flag == NE indicates failure
}
void MacroAssembler::compiler_fast_unlock_object(ConditionRegister flag, Register oop, Register box,
Register temp, Register displaced_header, Register current_header) {
assert_different_registers(oop, box, temp, displaced_header, current_header);
assert(flag != CCR0, "bad condition register");
Label cont;
Label object_has_monitor;
// Always do locking in runtime.
if (EmitSync & 0x01) {
cmpdi(flag, oop, 0); // Oop can't be 0 here => always false.
return;
}
if (UseBiasedLocking) {
biased_locking_exit(flag, oop, current_header, cont);
}
// Find the lock address and load the displaced header from the stack.
ld(displaced_header, BasicLock::displaced_header_offset_in_bytes(), box);
// If the displaced header is 0, we have a recursive unlock.
cmpdi(flag, displaced_header, 0);
beq(flag, cont);
// Handle existing monitor.
if ((EmitSync & 0x02) == 0) {
// The object has an existing monitor iff (mark & monitor_value) != 0.
ld(current_header, oopDesc::mark_offset_in_bytes(), oop);
andi(temp, current_header, markOopDesc::monitor_value);
cmpdi(flag, temp, 0);
bne(flag, object_has_monitor);
}
// Check if it is still a light weight lock, this is is true if we see
// the stack address of the basicLock in the markOop of the object.
// Cmpxchg sets flag to cmpd(current_header, box).
cmpxchgd(/*flag=*/flag,
/*current_value=*/current_header,
/*compare_value=*/box,
/*exchange_value=*/displaced_header,
/*where=*/oop,
MacroAssembler::MemBarRel,
MacroAssembler::cmpxchgx_hint_release_lock(),
noreg,
&cont);
assert(oopDesc::mark_offset_in_bytes() == 0, "offset of _mark is not 0");
// Handle existing monitor.
if ((EmitSync & 0x02) == 0) {
b(cont);
bind(object_has_monitor);
addi(current_header, current_header, -markOopDesc::monitor_value); // monitor
ld(temp, ObjectMonitor::owner_offset_in_bytes(), current_header);
ld(displaced_header, ObjectMonitor::recursions_offset_in_bytes(), current_header);
xorr(temp, R16_thread, temp); // Will be 0 if we are the owner.
orr(temp, temp, displaced_header); // Will be 0 if there are 0 recursions.
cmpdi(flag, temp, 0);
bne(flag, cont);
ld(temp, ObjectMonitor::EntryList_offset_in_bytes(), current_header);
ld(displaced_header, ObjectMonitor::cxq_offset_in_bytes(), current_header);
orr(temp, temp, displaced_header); // Will be 0 if both are 0.
cmpdi(flag, temp, 0);
bne(flag, cont);
release();
std(temp, ObjectMonitor::owner_offset_in_bytes(), current_header);
}
bind(cont);
// flag == EQ indicates success
// flag == NE indicates failure
}
// Write serialization page so VM thread can do a pseudo remote membar.
// We use the current thread pointer to calculate a thread specific
// offset to write to within the page. This minimizes bus traffic
// due to cache line collision.
void MacroAssembler::serialize_memory(Register thread, Register tmp1, Register tmp2) {
srdi(tmp2, thread, os::get_serialize_page_shift_count());
int mask = os::vm_page_size() - sizeof(int);
if (Assembler::is_simm(mask, 16)) {
andi(tmp2, tmp2, mask);
} else {
lis(tmp1, (int)((signed short) (mask >> 16)));
ori(tmp1, tmp1, mask & 0x0000ffff);
andr(tmp2, tmp2, tmp1);
}
load_const(tmp1, (long) os::get_memory_serialize_page());
release();
stwx(R0, tmp1, tmp2);
}
// GC barrier helper macros
// Write the card table byte if needed.
void MacroAssembler::card_write_barrier_post(Register Rstore_addr, Register Rnew_val, Register Rtmp) {
CardTableModRefBS* bs = (CardTableModRefBS*) Universe::heap()->barrier_set();
assert(bs->kind() == BarrierSet::CardTableModRef ||
bs->kind() == BarrierSet::CardTableExtension, "wrong barrier");
#ifdef ASSERT
cmpdi(CCR0, Rnew_val, 0);
asm_assert_ne("null oop not allowed", 0x321);
#endif
card_table_write(bs->byte_map_base, Rtmp, Rstore_addr);
}
// Write the card table byte.
void MacroAssembler::card_table_write(jbyte* byte_map_base, Register Rtmp, Register Robj) {
assert_different_registers(Robj, Rtmp, R0);
load_const_optimized(Rtmp, (address)byte_map_base, R0);
srdi(Robj, Robj, CardTableModRefBS::card_shift);
li(R0, 0); // dirty
if (UseConcMarkSweepGC) release();
stbx(R0, Rtmp, Robj);
}
#ifndef SERIALGC
// General G1 pre-barrier generator.
// Goal: record the previous value if it is not null.
void MacroAssembler::g1_write_barrier_pre(Register Robj, RegisterOrConstant offset, Register Rpre_val,
Register Rtmp1, Register Rtmp2, bool needs_frame) {
Label runtime, filtered;
// Is marking active?
if (in_bytes(PtrQueue::byte_width_of_active()) == 4) {
lwz(Rtmp1, in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active()), R16_thread);
} else {
guarantee(in_bytes(PtrQueue::byte_width_of_active()) == 1, "Assumption");
lbz(Rtmp1, in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active()), R16_thread);
}
cmpdi(CCR0, Rtmp1, 0);
beq(CCR0, filtered);
// Do we need to load the previous value?
if (Robj != noreg) {
// Load the previous value...
if (UseCompressedOops) {
lwz(Rpre_val, offset, Robj);
} else {
ld(Rpre_val, offset, Robj);
}
// Previous value has been loaded into Rpre_val.
}
assert(Rpre_val != noreg, "must have a real register");
// Is the previous value null?
cmpdi(CCR0, Rpre_val, 0);
beq(CCR0, filtered);
if (Robj != noreg && UseCompressedOops) {
decode_heap_oop_not_null(Rpre_val);
}
// OK, it's not filtered, so we'll need to call enqueue. In the normal
// case, pre_val will be a scratch G-reg, but there are some cases in
// which it's an O-reg. In the first case, do a normal call. In the
// latter, do a save here and call the frameless version.
// Can we store original value in the thread's buffer?
// Is index == 0?
// (The index field is typed as size_t.)
const Register Rbuffer = Rtmp1, Rindex = Rtmp2;
ld(Rindex, in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_index()), R16_thread);
cmpdi(CCR0, Rindex, 0);
beq(CCR0, runtime); // If index == 0, goto runtime.
ld(Rbuffer, in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_buf()), R16_thread);
addi(Rindex, Rindex, -wordSize); // Decrement index.
std(Rindex, in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_index()), R16_thread);
// Record the previous value.
stdx(Rpre_val, Rbuffer, Rindex);
b(filtered);
bind(runtime);
// VM call need frame to access(write) O register.
if (needs_frame) {
save_LR_CR(Rtmp1);
push_frame_abi112(0, Rtmp2);
}
if (Rpre_val->is_volatile() && Robj == noreg) mr(R31, Rpre_val); // Save pre_val across C call if it was preloaded.
call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_pre), Rpre_val, R16_thread);
if (Rpre_val->is_volatile() && Robj == noreg) mr(Rpre_val, R31); // restore
if (needs_frame) {
pop_frame();
restore_LR_CR(Rtmp1);
}
bind(filtered);
}
// General G1 post-barrier generator
// Store cross-region card.
void MacroAssembler::g1_write_barrier_post(Register Rstore_addr, Register Rnew_val, Register Rtmp1, Register Rtmp2, Register Rtmp3, Label *filtered_ext) {
Label runtime, filtered_int;
Label& filtered = (filtered_ext != NULL) ? *filtered_ext : filtered_int;
assert_different_registers(Rstore_addr, Rnew_val, Rtmp1, Rtmp2);
G1SATBCardTableModRefBS* bs = (G1SATBCardTableModRefBS*) Universe::heap()->barrier_set();
assert(bs->kind() == BarrierSet::G1SATBCT ||
bs->kind() == BarrierSet::G1SATBCTLogging, "wrong barrier");
// Does store cross heap regions?
if (G1RSBarrierRegionFilter) {
xorr(Rtmp1, Rstore_addr, Rnew_val);
srdi_(Rtmp1, Rtmp1, HeapRegion::LogOfHRGrainBytes);
beq(CCR0, filtered);
}
// Crosses regions, storing NULL?
#ifdef ASSERT
cmpdi(CCR0, Rnew_val, 0);
asm_assert_ne("null oop not allowed (G1)", 0x322); // Checked by caller on PPC64, so following branch is obsolete:
//beq(CCR0, filtered);
#endif
// Storing region crossing non-NULL, is card already dirty?
assert(sizeof(*bs->byte_map_base) == sizeof(jbyte), "adjust this code");
const Register Rcard_addr = Rtmp1;
Register Rbase = Rtmp2;
load_const_optimized(Rbase, (address)bs->byte_map_base, /*temp*/ Rtmp3);
srdi(Rcard_addr, Rstore_addr, CardTableModRefBS::card_shift);
// Get the address of the card.
lbzx(/*card value*/ Rtmp3, Rbase, Rcard_addr);
assert(CardTableModRefBS::dirty_card_val() == 0, "otherwise check this code");
cmpwi(CCR0, Rtmp3 /* card value */, 0);
beq(CCR0, filtered);
// Storing a region crossing, non-NULL oop, card is clean.
// Dirty card and log.
li(Rtmp3, 0); // dirty
//release(); // G1: oops are allowed to get visible after dirty marking.
stbx(Rtmp3, Rbase, Rcard_addr);
add(Rcard_addr, Rbase, Rcard_addr); // This is the address which needs to get enqueued.
Rbase = noreg; // end of lifetime
const Register Rqueue_index = Rtmp2,
Rqueue_buf = Rtmp3;
ld(Rqueue_index, in_bytes(JavaThread::dirty_card_queue_offset() + PtrQueue::byte_offset_of_index()), R16_thread);
cmpdi(CCR0, Rqueue_index, 0);
beq(CCR0, runtime); // index == 0 then jump to runtime
ld(Rqueue_buf, in_bytes(JavaThread::dirty_card_queue_offset() + PtrQueue::byte_offset_of_buf()), R16_thread);
addi(Rqueue_index, Rqueue_index, -wordSize); // decrement index
std(Rqueue_index, in_bytes(JavaThread::dirty_card_queue_offset() + PtrQueue::byte_offset_of_index()), R16_thread);
stdx(Rcard_addr, Rqueue_buf, Rqueue_index); // store card
b(filtered);
bind(runtime);
// Save the live input values.
call_VM_leaf(CAST_FROM_FN_PTR(address, SharedRuntime::g1_wb_post), Rcard_addr, R16_thread);
bind(filtered_int);
}
#endif // SERIALGC
// Values for last_Java_pc, and last_Java_sp must comply to the rules
// in frame_ppc64.hpp.
void MacroAssembler::set_last_Java_frame(Register last_Java_sp, Register last_Java_pc) {
// Always set last_Java_pc and flags first because once last_Java_sp
// is visible has_last_Java_frame is true and users will look at the
// rest of the fields. (Note: flags should always be zero before we
// get here so doesn't need to be set.)
// Verify that last_Java_pc was zeroed on return to Java
asm_assert_mem8_is_zero(in_bytes(JavaThread::last_Java_pc_offset()), R16_thread,
"last_Java_pc not zeroed before leaving Java", 0x200);
// When returning from calling out from Java mode the frame anchor's
// last_Java_pc will always be set to NULL. It is set here so that
// if we are doing a call to native (not VM) that we capture the
// known pc and don't have to rely on the native call having a
// standard frame linkage where we can find the pc.
if (last_Java_pc != noreg)
std(last_Java_pc, in_bytes(JavaThread::last_Java_pc_offset()), R16_thread);
// set last_Java_sp last
std(last_Java_sp, in_bytes(JavaThread::last_Java_sp_offset()), R16_thread);
}
void MacroAssembler::reset_last_Java_frame(void) {
asm_assert_mem8_isnot_zero(in_bytes(JavaThread::last_Java_sp_offset()),
R16_thread, "SP was not set, still zero", 0x202);
BLOCK_COMMENT("reset_last_Java_frame {");
li(R0, 0);
// _last_Java_sp = 0
std(R0, in_bytes(JavaThread::last_Java_sp_offset()), R16_thread);
// _last_Java_pc = 0
std(R0, in_bytes(JavaThread::last_Java_pc_offset()), R16_thread);
BLOCK_COMMENT("} reset_last_Java_frame");
}
void MacroAssembler::set_top_ijava_frame_at_SP_as_last_Java_frame(Register sp, Register tmp1) {
assert_different_registers(sp, tmp1);
// sp points to a TOP_IJAVA_FRAME, retrieve frame's PC via
// TOP_IJAVA_FRAME_ABI.
// FIXME: assert that we really have a TOP_IJAVA_FRAME here!
#ifdef CC_INTERP
ld(tmp1/*pc*/, _top_ijava_frame_abi(frame_manager_lr), sp);
#else
Unimplemented();
#endif
set_last_Java_frame(/*sp=*/sp, /*pc=*/tmp1);
}
void MacroAssembler::get_vm_result(Register oop_result) {
// Read:
// R16_thread
// R16_thread->in_bytes(JavaThread::vm_result_offset())
//
// Updated:
// oop_result
// R16_thread->in_bytes(JavaThread::vm_result_offset())
ld(oop_result, in_bytes(JavaThread::vm_result_offset()), R16_thread);
li(R0, 0);
std(R0, in_bytes(JavaThread::vm_result_offset()), R16_thread);
verify_oop(oop_result);
}
void MacroAssembler::get_vm_result_2(Register metadata_result) {
// Read:
// R16_thread
// R16_thread->in_bytes(JavaThread::vm_result_2_offset())
//
// Updated:
// metadata_result
// R16_thread->in_bytes(JavaThread::vm_result_2_offset())
ld(metadata_result, in_bytes(JavaThread::vm_result_2_offset()), R16_thread);
li(R0, 0);
std(R0, in_bytes(JavaThread::vm_result_2_offset()), R16_thread);
}
void MacroAssembler::encode_klass_not_null(Register dst, Register src) {
if (src == noreg) src = dst;
if (Universe::narrow_klass_base() != 0) {
load_const(R0, Universe::narrow_klass_base());
sub(dst, src, R0);
}
if (Universe::narrow_klass_shift() != 0 ||
Universe::narrow_klass_base() == 0 && src != dst) { // Move required.
srdi(dst, src, Universe::narrow_klass_shift());
}
}
void MacroAssembler::store_klass(Register dst_oop, Register klass, Register ck) {
if (UseCompressedClassPointers) {
encode_klass_not_null(ck, klass);
stw(ck, oopDesc::klass_offset_in_bytes(), dst_oop);
} else {
std(klass, oopDesc::klass_offset_in_bytes(), dst_oop);
}
}
int MacroAssembler::instr_size_for_decode_klass_not_null() {
if (!UseCompressedClassPointers) return 0;
int num_instrs = 1; // shift or move
if (Universe::narrow_klass_base() != 0) num_instrs = 7; // shift + load const + add
return num_instrs * BytesPerInstWord;
}
void MacroAssembler::decode_klass_not_null(Register dst, Register src) {
if (src == noreg) src = dst;
Register shifted_src = src;
if (Universe::narrow_klass_shift() != 0 ||
Universe::narrow_klass_base() == 0 && src != dst) { // Move required.
shifted_src = dst;
sldi(shifted_src, src, Universe::narrow_klass_shift());
}
if (Universe::narrow_klass_base() != 0) {
load_const(R0, Universe::narrow_klass_base());
add(dst, shifted_src, R0);
}
}
void MacroAssembler::load_klass(Register dst, Register src) {
if (UseCompressedClassPointers) {
lwz(dst, oopDesc::klass_offset_in_bytes(), src);
// Attention: no null check here!
decode_klass_not_null(dst, dst);
} else {
ld(dst, oopDesc::klass_offset_in_bytes(), src);
}
}
void MacroAssembler::load_klass_with_trap_null_check(Register dst, Register src) {
if (!os::zero_page_read_protected()) {
if (TrapBasedNullChecks) {
trap_null_check(src);
}
}
load_klass(dst, src);
}
void MacroAssembler::reinit_heapbase(Register d, Register tmp) {
if (Universe::heap() != NULL) {
if (Universe::narrow_oop_base() == NULL) {
Assembler::xorr(R30, R30, R30);
} else {
load_const(R30, Universe::narrow_ptrs_base(), tmp);
}
} else {
load_const(R30, Universe::narrow_ptrs_base_addr(), tmp);
ld(R30, 0, R30);
}
}
/////////////////////////////////////////// String intrinsics ////////////////////////////////////////////
// Search for a single jchar in an jchar[].
//
// Assumes that result differs from all other registers.
//
// Haystack, needle are the addresses of jchar-arrays.
// NeedleChar is needle[0] if it is known at compile time.
// Haycnt is the length of the haystack. We assume haycnt >=1.
//
// Preserves haystack, haycnt, kills all other registers.
//
// If needle == R0, we search for the constant needleChar.
void MacroAssembler::string_indexof_1(Register result, Register haystack, Register haycnt,
Register needle, jchar needleChar,
Register tmp1, Register tmp2) {
assert_different_registers(result, haystack, haycnt, needle, tmp1, tmp2);
Label L_InnerLoop, L_FinalCheck, L_Found1, L_Found2, L_Found3, L_NotFound, L_End;
Register needle0 = needle, // Contains needle[0].
addr = tmp1,
ch1 = tmp2,
ch2 = R0;
//2 (variable) or 3 (const):
if (needle != R0) lhz(needle0, 0, needle); // Preload needle character, needle has len==1.
dcbtct(haystack, 0x00); // Indicate R/O access to haystack.
srwi_(tmp2, haycnt, 1); // Shift right by exact_log2(UNROLL_FACTOR).
mr(addr, haystack);
beq(CCR0, L_FinalCheck);
mtctr(tmp2); // Move to count register.
//8:
bind(L_InnerLoop); // Main work horse (2x unrolled search loop).
lhz(ch1, 0, addr); // Load characters from haystack.
lhz(ch2, 2, addr);
(needle != R0) ? cmpw(CCR0, ch1, needle0) : cmplwi(CCR0, ch1, needleChar);
(needle != R0) ? cmpw(CCR1, ch2, needle0) : cmplwi(CCR1, ch2, needleChar);
beq(CCR0, L_Found1); // Did we find the needle?
beq(CCR1, L_Found2);
addi(addr, addr, 4);
bdnz(L_InnerLoop);
//16:
bind(L_FinalCheck);
andi_(R0, haycnt, 1);
beq(CCR0, L_NotFound);
lhz(ch1, 0, addr); // One position left at which we have to compare.
(needle != R0) ? cmpw(CCR1, ch1, needle0) : cmplwi(CCR1, ch1, needleChar);
beq(CCR1, L_Found3);
//21:
bind(L_NotFound);
li(result, -1); // Not found.
b(L_End);
bind(L_Found2);
addi(addr, addr, 2);
//24:
bind(L_Found1);
bind(L_Found3); // Return index ...
subf(addr, haystack, addr); // relative to haystack,
srdi(result, addr, 1); // in characters.
bind(L_End);
}
// Implementation of IndexOf for jchar arrays.
//
// The length of haystack and needle are not constant, i.e. passed in a register.
//
// Preserves registers haystack, needle.
// Kills registers haycnt, needlecnt.
// Assumes that result differs from all other registers.
// Haystack, needle are the addresses of jchar-arrays.
// Haycnt, needlecnt are the lengths of them, respectively.
//
// Needlecntval must be zero or 15-bit unsigned immediate and > 1.
void MacroAssembler::string_indexof(Register result, Register haystack, Register haycnt,
Register needle, ciTypeArray* needle_values, Register needlecnt, int needlecntval,
Register tmp1, Register tmp2, Register tmp3, Register tmp4) {
// Ensure 0<needlecnt<=haycnt in ideal graph as prerequisite!
Label L_TooShort, L_Found, L_NotFound, L_End;
Register last_addr = haycnt, // Kill haycnt at the beginning.
addr = tmp1,
n_start = tmp2,
ch1 = tmp3,
ch2 = R0;
// **************************************************************************************************
// Prepare for main loop: optimized for needle count >=2, bail out otherwise.
// **************************************************************************************************
//1 (variable) or 3 (const):
dcbtct(needle, 0x00); // Indicate R/O access to str1.
dcbtct(haystack, 0x00); // Indicate R/O access to str2.
// Compute last haystack addr to use if no match gets found.
if (needlecntval == 0) { // variable needlecnt
//3:
subf(ch1, needlecnt, haycnt); // Last character index to compare is haycnt-needlecnt.
addi(addr, haystack, -2); // Accesses use pre-increment.
cmpwi(CCR6, needlecnt, 2);
blt(CCR6, L_TooShort); // Variable needlecnt: handle short needle separately.
slwi(ch1, ch1, 1); // Scale to number of bytes.
lwz(n_start, 0, needle); // Load first 2 characters of needle.
add(last_addr, haystack, ch1); // Point to last address to compare (haystack+2*(haycnt-needlecnt)).
addi(needlecnt, needlecnt, -2); // Rest of needle.
} else { // constant needlecnt
guarantee(needlecntval != 1, "IndexOf with single-character needle must be handled separately");
assert((needlecntval & 0x7fff) == needlecntval, "wrong immediate");
//5:
addi(ch1, haycnt, -needlecntval); // Last character index to compare is haycnt-needlecnt.
lwz(n_start, 0, needle); // Load first 2 characters of needle.
addi(addr, haystack, -2); // Accesses use pre-increment.
slwi(ch1, ch1, 1); // Scale to number of bytes.
add(last_addr, haystack, ch1); // Point to last address to compare (haystack+2*(haycnt-needlecnt)).
li(needlecnt, needlecntval-2); // Rest of needle.
}
// Main Loop (now we have at least 3 characters).
//11:
Label L_OuterLoop, L_InnerLoop, L_FinalCheck, L_Comp1, L_Comp2, L_Comp3;
bind(L_OuterLoop); // Search for 1st 2 characters.
Register addr_diff = tmp4;
subf(addr_diff, addr, last_addr); // Difference between already checked address and last address to check.
addi(addr, addr, 2); // This is the new address we want to use for comparing.
srdi_(ch2, addr_diff, 2);
beq(CCR0, L_FinalCheck); // 2 characters left?
mtctr(ch2); // addr_diff/4
//16:
bind(L_InnerLoop); // Main work horse (2x unrolled search loop)
lwz(ch1, 0, addr); // Load 2 characters of haystack (ignore alignment).
lwz(ch2, 2, addr);
cmpw(CCR0, ch1, n_start); // Compare 2 characters (1 would be sufficient but try to reduce branches to CompLoop).
cmpw(CCR1, ch2, n_start);
beq(CCR0, L_Comp1); // Did we find the needle start?
beq(CCR1, L_Comp2);
addi(addr, addr, 4);
bdnz(L_InnerLoop);
//24:
bind(L_FinalCheck);
rldicl_(addr_diff, addr_diff, 64-1, 63); // Remaining characters not covered by InnerLoop: (addr_diff>>1)&1.
beq(CCR0, L_NotFound);
lwz(ch1, 0, addr); // One position left at which we have to compare.
cmpw(CCR1, ch1, n_start);
beq(CCR1, L_Comp3);
//29:
bind(L_NotFound);
li(result, -1); // not found
b(L_End);
// **************************************************************************************************
// Special Case: unfortunately, the variable needle case can be called with needlecnt<2
// **************************************************************************************************
//31:
if ((needlecntval>>1) !=1 ) { // Const needlecnt is 2 or 3? Reduce code size.
int nopcnt = 5;
if (needlecntval !=0 ) ++nopcnt; // Balance alignment (other case: see below).
if (needlecntval == 0) { // We have to handle these cases separately.
Label L_OneCharLoop;
bind(L_TooShort);
mtctr(haycnt);
lhz(n_start, 0, needle); // First character of needle
bind(L_OneCharLoop);
lhzu(ch1, 2, addr);
cmpw(CCR1, ch1, n_start);
beq(CCR1, L_Found); // Did we find the one character needle?
bdnz(L_OneCharLoop);
li(result, -1); // Not found.
b(L_End);
} // 8 instructions, so no impact on alignment.
for (int x = 0; x < nopcnt; ++x) nop();
}
// **************************************************************************************************
// Regular Case Part II: compare rest of needle (first 2 characters have been compared already)
// **************************************************************************************************
// Compare the rest
//36 if needlecntval==0, else 37:
bind(L_Comp2);
addi(addr, addr, 2); // First comparison has failed, 2nd one hit.
bind(L_Comp1); // Addr points to possible needle start.
bind(L_Comp3); // Could have created a copy and use a different return address but saving code size here.
if (needlecntval != 2) { // Const needlecnt==2?
if (needlecntval != 3) {
if (needlecntval == 0) beq(CCR6, L_Found); // Variable needlecnt==2?
Register ind_reg = tmp4;
li(ind_reg, 2*2); // First 2 characters are already compared, use index 2.
mtctr(needlecnt); // Decremented by 2, still > 0.
//40:
Label L_CompLoop;
bind(L_CompLoop);
lhzx(ch2, needle, ind_reg);
lhzx(ch1, addr, ind_reg);
cmpw(CCR1, ch1, ch2);
bne(CCR1, L_OuterLoop);
addi(ind_reg, ind_reg, 2);
bdnz(L_CompLoop);
} else { // No loop required if there's only one needle character left.
lhz(ch2, 2*2, needle);
lhz(ch1, 2*2, addr);
cmpw(CCR1, ch1, ch2);
bne(CCR1, L_OuterLoop);
}
}
// Return index ...
//46:
bind(L_Found);
subf(addr, haystack, addr); // relative to haystack, ...
srdi(result, addr, 1); // in characters.
//48:
bind(L_End);
}
// Implementation of Compare for jchar arrays.
//
// Kills the registers str1, str2, cnt1, cnt2.
// Kills cr0, ctr.
// Assumes that result differes from the input registers.
void MacroAssembler::string_compare(Register str1_reg, Register str2_reg, Register cnt1_reg, Register cnt2_reg,
Register result_reg, Register tmp_reg) {
assert_different_registers(result_reg, str1_reg, str2_reg, cnt1_reg, cnt2_reg, tmp_reg);
Label Ldone, Lslow_case, Lslow_loop, Lfast_loop;
Register cnt_diff = R0,
limit_reg = cnt1_reg,
chr1_reg = result_reg,
chr2_reg = cnt2_reg,
addr_diff = str2_reg;
// Offset 0 should be 32 byte aligned.
//-4:
dcbtct(str1_reg, 0x00); // Indicate R/O access to str1.
dcbtct(str2_reg, 0x00); // Indicate R/O access to str2.
//-2:
// Compute min(cnt1, cnt2) and check if 0 (bail out if we don't need to compare characters).
subf(result_reg, cnt2_reg, cnt1_reg); // difference between cnt1/2
subf_(addr_diff, str1_reg, str2_reg); // alias?
beq(CCR0, Ldone); // return cnt difference if both ones are identical
srawi(limit_reg, result_reg, 31); // generate signmask (cnt1/2 must be non-negative so cnt_diff can't overflow)
mr(cnt_diff, result_reg);
andr(limit_reg, result_reg, limit_reg); // difference or zero (negative): cnt1<cnt2 ? cnt1-cnt2 : 0
add_(limit_reg, cnt2_reg, limit_reg); // min(cnt1, cnt2)==0?
beq(CCR0, Ldone); // return cnt difference if one has 0 length
lhz(chr1_reg, 0, str1_reg); // optional: early out if first characters mismatch
lhzx(chr2_reg, str1_reg, addr_diff); // optional: early out if first characters mismatch
addi(tmp_reg, limit_reg, -1); // min(cnt1, cnt2)-1
subf_(result_reg, chr2_reg, chr1_reg); // optional: early out if first characters mismatch
bne(CCR0, Ldone); // optional: early out if first characters mismatch
// Set loop counter by scaling down tmp_reg
srawi_(chr2_reg, tmp_reg, exact_log2(4)); // (min(cnt1, cnt2)-1)/4
ble(CCR0, Lslow_case); // need >4 characters for fast loop
andi(limit_reg, tmp_reg, 4-1); // remaining characters
// Adapt str1_reg str2_reg for the first loop iteration
mtctr(chr2_reg); // (min(cnt1, cnt2)-1)/4
addi(limit_reg, limit_reg, 4+1); // compare last 5-8 characters in slow_case if mismatch found in fast_loop
//16:
// Compare the rest of the characters
bind(Lfast_loop);
ld(chr1_reg, 0, str1_reg);
ldx(chr2_reg, str1_reg, addr_diff);
cmpd(CCR0, chr2_reg, chr1_reg);
bne(CCR0, Lslow_case); // return chr1_reg
addi(str1_reg, str1_reg, 4*2);
bdnz(Lfast_loop);
addi(limit_reg, limit_reg, -4); // no mismatch found in fast_loop, only 1-4 characters missing
//23:
bind(Lslow_case);
mtctr(limit_reg);
//24:
bind(Lslow_loop);
lhz(chr1_reg, 0, str1_reg);
lhzx(chr2_reg, str1_reg, addr_diff);
subf_(result_reg, chr2_reg, chr1_reg);
bne(CCR0, Ldone); // return chr1_reg
addi(str1_reg, str1_reg, 1*2);
bdnz(Lslow_loop);
//30:
// If strings are equal up to min length, return the length difference.
mr(result_reg, cnt_diff);
nop(); // alignment
//32:
// Otherwise, return the difference between the first mismatched chars.
bind(Ldone);
}
// Compare char[] arrays.
//
// str1_reg USE only
// str2_reg USE only
// cnt_reg USE_DEF, due to tmp reg shortage
// result_reg DEF only, might compromise USE only registers
void MacroAssembler::char_arrays_equals(Register str1_reg, Register str2_reg, Register cnt_reg, Register result_reg,
Register tmp1_reg, Register tmp2_reg, Register tmp3_reg, Register tmp4_reg,
Register tmp5_reg) {
// Str1 may be the same register as str2 which can occur e.g. after scalar replacement.
assert_different_registers(result_reg, str1_reg, cnt_reg, tmp1_reg, tmp2_reg, tmp3_reg, tmp4_reg, tmp5_reg);
assert_different_registers(result_reg, str2_reg, cnt_reg, tmp1_reg, tmp2_reg, tmp3_reg, tmp4_reg, tmp5_reg);
// Offset 0 should be 32 byte aligned.
Label Linit_cbc, Lcbc, Lloop, Ldone_true, Ldone_false;
Register index_reg = tmp5_reg;
Register cbc_iter = tmp4_reg;
//-1:
dcbtct(str1_reg, 0x00); // Indicate R/O access to str1.
dcbtct(str2_reg, 0x00); // Indicate R/O access to str2.
//1:
andi(cbc_iter, cnt_reg, 4-1); // Remaining iterations after 4 java characters per iteration loop.
li(index_reg, 0); // init
li(result_reg, 0); // assume false
srwi_(tmp2_reg, cnt_reg, exact_log2(4)); // Div: 4 java characters per iteration (main loop).
cmpwi(CCR1, cbc_iter, 0); // CCR1 = (cbc_iter==0)
beq(CCR0, Linit_cbc); // too short
mtctr(tmp2_reg);
//8:
bind(Lloop);
ldx(tmp1_reg, str1_reg, index_reg);
ldx(tmp2_reg, str2_reg, index_reg);
cmpd(CCR0, tmp1_reg, tmp2_reg);
bne(CCR0, Ldone_false); // Unequal char pair found -> done.
addi(index_reg, index_reg, 4*sizeof(jchar));
bdnz(Lloop);
//14:
bind(Linit_cbc);
beq(CCR1, Ldone_true);
mtctr(cbc_iter);
//16:
bind(Lcbc);
lhzx(tmp1_reg, str1_reg, index_reg);
lhzx(tmp2_reg, str2_reg, index_reg);
cmpw(CCR0, tmp1_reg, tmp2_reg);
bne(CCR0, Ldone_false); // Unequal char pair found -> done.
addi(index_reg, index_reg, 1*sizeof(jchar));
bdnz(Lcbc);
nop();
bind(Ldone_true);
li(result_reg, 1);
//24:
bind(Ldone_false);
}
void MacroAssembler::char_arrays_equalsImm(Register str1_reg, Register str2_reg, int cntval, Register result_reg,
Register tmp1_reg, Register tmp2_reg) {
// Str1 may be the same register as str2 which can occur e.g. after scalar replacement.
assert_different_registers(result_reg, str1_reg, tmp1_reg, tmp2_reg);
assert_different_registers(result_reg, str2_reg, tmp1_reg, tmp2_reg);
assert(sizeof(jchar) == 2, "must be");
assert(cntval >= 0 && ((cntval & 0x7fff) == cntval), "wrong immediate");
Label Ldone_false;
if (cntval < 16) { // short case
if (cntval != 0) li(result_reg, 0); // assume false
const int num_bytes = cntval*sizeof(jchar);
int index = 0;
for (int next_index; (next_index = index + 8) <= num_bytes; index = next_index) {
ld(tmp1_reg, index, str1_reg);
ld(tmp2_reg, index, str2_reg);
cmpd(CCR0, tmp1_reg, tmp2_reg);
bne(CCR0, Ldone_false);
}
if (cntval & 2) {
lwz(tmp1_reg, index, str1_reg);
lwz(tmp2_reg, index, str2_reg);
cmpw(CCR0, tmp1_reg, tmp2_reg);
bne(CCR0, Ldone_false);
index += 4;
}
if (cntval & 1) {
lhz(tmp1_reg, index, str1_reg);
lhz(tmp2_reg, index, str2_reg);
cmpw(CCR0, tmp1_reg, tmp2_reg);
bne(CCR0, Ldone_false);
}
// fallthrough: true
} else {
Label Lloop;
Register index_reg = tmp1_reg;
const int loopcnt = cntval/4;
assert(loopcnt > 0, "must be");
// Offset 0 should be 32 byte aligned.
//2:
dcbtct(str1_reg, 0x00); // Indicate R/O access to str1.
dcbtct(str2_reg, 0x00); // Indicate R/O access to str2.
li(tmp2_reg, loopcnt);
li(index_reg, 0); // init
li(result_reg, 0); // assume false
mtctr(tmp2_reg);
//8:
bind(Lloop);
ldx(R0, str1_reg, index_reg);
ldx(tmp2_reg, str2_reg, index_reg);
cmpd(CCR0, R0, tmp2_reg);
bne(CCR0, Ldone_false); // Unequal char pair found -> done.
addi(index_reg, index_reg, 4*sizeof(jchar));
bdnz(Lloop);
//14:
if (cntval & 2) {
lwzx(R0, str1_reg, index_reg);
lwzx(tmp2_reg, str2_reg, index_reg);
cmpw(CCR0, R0, tmp2_reg);
bne(CCR0, Ldone_false);
if (cntval & 1) addi(index_reg, index_reg, 2*sizeof(jchar));
}
if (cntval & 1) {
lhzx(R0, str1_reg, index_reg);
lhzx(tmp2_reg, str2_reg, index_reg);
cmpw(CCR0, R0, tmp2_reg);
bne(CCR0, Ldone_false);
}
// fallthru: true
}
li(result_reg, 1);
bind(Ldone_false);
}
void MacroAssembler::asm_assert(bool check_equal, const char *msg, int id) {
#ifdef ASSERT
Label ok;
if (check_equal) {
beq(CCR0, ok);
} else {
bne(CCR0, ok);
}
stop(msg, id);
bind(ok);
#endif
}
void MacroAssembler::asm_assert_mems_zero(bool check_equal, int size, int mem_offset,
Register mem_base, const char* msg, int id) {
#ifdef ASSERT
switch (size) {
case 4:
lwz(R0, mem_offset, mem_base);
cmpwi(CCR0, R0, 0);
break;
case 8:
ld(R0, mem_offset, mem_base);
cmpdi(CCR0, R0, 0);
break;
default:
ShouldNotReachHere();
}
asm_assert(check_equal, msg, id);
#endif // ASSERT
}
void MacroAssembler::verify_thread() {
if (VerifyThread) {
unimplemented("'VerifyThread' currently not implemented on PPC");
}
}
// READ: oop. KILL: R0. Volatile floats perhaps.
void MacroAssembler::verify_oop(Register oop, const char* msg) {
if (!VerifyOops) {
return;
}
// will be preserved.
Register tmp = R11;
assert(oop != tmp, "precondition");
unsigned int nbytes_save = 10*8; // 10 volatile gprs
address/* FunctionDescriptor** */fd =
StubRoutines::verify_oop_subroutine_entry_address();
// save tmp
mr(R0, tmp);
// kill tmp
save_LR_CR(tmp);
push_frame_abi112(nbytes_save, tmp);
// restore tmp
mr(tmp, R0);
save_volatile_gprs(R1_SP, 112); // except R0
// load FunctionDescriptor**
load_const(tmp, fd);
// load FunctionDescriptor*
ld(tmp, 0, tmp);
mr(R4_ARG2, oop);
load_const(R3_ARG1, (address)msg);
// call destination for its side effect
call_c(tmp);
restore_volatile_gprs(R1_SP, 112); // except R0
pop_frame();
// save tmp
mr(R0, tmp);
// kill tmp
restore_LR_CR(tmp);
// restore tmp
mr(tmp, R0);
}
const char* stop_types[] = {
"stop",
"untested",
"unimplemented",
"shouldnotreachhere"
};
static void stop_on_request(int tp, const char* msg) {
tty->print("PPC assembly code requires stop: (%s) %s\n", (void *)stop_types[tp%/*stop_end*/4], msg);
guarantee(false, err_msg("PPC assembly code requires stop: %s", msg));
}
// Call a C-function that prints output.
void MacroAssembler::stop(int type, const char* msg, int id) {
#ifndef PRODUCT
block_comment(err_msg("stop: %s %s {", stop_types[type%stop_end], msg));
#else
block_comment("stop {");
#endif
// setup arguments
load_const_optimized(R3_ARG1, type);
load_const_optimized(R4_ARG2, (void *)msg, /*tmp=*/R0);
call_VM_leaf(CAST_FROM_FN_PTR(address, stop_on_request), R3_ARG1, R4_ARG2);
illtrap();
emit_int32(id);
block_comment("} stop;");
}
#ifndef PRODUCT
// Write pattern 0x0101010101010101 in memory region [low-before, high+after].
// Val, addr are temp registers.
// If low == addr, addr is killed.
// High is preserved.
void MacroAssembler::zap_from_to(Register low, int before, Register high, int after, Register val, Register addr) {
if (!ZapMemory) return;
assert_different_registers(low, val);
BLOCK_COMMENT("zap memory region {");
load_const_optimized(val, 0x0101010101010101);
int size = before + after;
if (low == high && size < 5 && size > 0) {
int offset = -before*BytesPerWord;
for (int i = 0; i < size; ++i) {
std(val, offset, low);
offset += (1*BytesPerWord);
}
} else {
addi(addr, low, -before*BytesPerWord);
assert_different_registers(high, val);
if (after) addi(high, high, after * BytesPerWord);
Label loop;
bind(loop);
std(val, 0, addr);
addi(addr, addr, 8);
cmpd(CCR6, addr, high);
ble(CCR6, loop);
if (after) addi(high, high, -after * BytesPerWord); // Correct back to old value.
}
BLOCK_COMMENT("} zap memory region");
}
#endif // !PRODUCT