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v8/src/assembler-arm.cc
deanm@chromium.org 891ae83e18 Remove some craaaazy trailing whitespace. 
git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@397 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2008-09-30 11:41:58 +00:00

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// Copyright (c) 1994-2006 Sun Microsystems Inc.
// All Rights Reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions
// are met:
//
// - Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// - Redistribution in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the
// distribution.
//
// - Neither the name of Sun Microsystems or the names of contributors may
// be used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
// FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
// COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
// OF THE POSSIBILITY OF SUCH DAMAGE.
// The original source code covered by the above license above has been modified
// significantly by Google Inc.
// Copyright 2006-2008 the V8 project authors. All rights reserved.
#include "v8.h"
#include "assembler-arm-inl.h"
#include "serialize.h"
namespace v8 { namespace internal {
// -----------------------------------------------------------------------------
// Implementation of Register and CRegister
Register no_reg = { -1 };
Register r0 = { 0 };
Register r1 = { 1 };
Register r2 = { 2 };
Register r3 = { 3 };
Register r4 = { 4 };
Register r5 = { 5 };
Register r6 = { 6 };
Register r7 = { 7 };
Register r8 = { 8 };
Register r9 = { 9 };
Register r10 = { 10 };
Register fp = { 11 };
Register ip = { 12 };
Register sp = { 13 };
Register lr = { 14 };
Register pc = { 15 };
CRegister no_creg = { -1 };
CRegister cr0 = { 0 };
CRegister cr1 = { 1 };
CRegister cr2 = { 2 };
CRegister cr3 = { 3 };
CRegister cr4 = { 4 };
CRegister cr5 = { 5 };
CRegister cr6 = { 6 };
CRegister cr7 = { 7 };
CRegister cr8 = { 8 };
CRegister cr9 = { 9 };
CRegister cr10 = { 10 };
CRegister cr11 = { 11 };
CRegister cr12 = { 12 };
CRegister cr13 = { 13 };
CRegister cr14 = { 14 };
CRegister cr15 = { 15 };
// In order to determine the pc store offset, we execute a small code sequence.
// See ARM Architecture Reference Manual section A-2.4.3
// Note that 'str pc, [sp]' and 'stmia sp, {pc}' were using different offsets
// under the QEMU emulator (now fixed), so we are careful to test the actual
// instruction we are interested in (stmia).
int PcStoreOffset() {
#if !defined(__arm__)
// Building an ARM emulator based target. The emulator is wired for 8 byte
// pc offsets as is the default in the spec.
static int pc_store_offset = 8;
#elif defined(__arm__) && !defined(__thumb__)
// __arm__ may be defined in thumb mode.
static int pc_store_offset = -1;
asm volatile(
"sub sp, sp, #4 \n\t"
"sub r1, pc, #4 \n\t"
"stmia sp, {pc} \n\t"
"ldr r0, [sp] \n\t"
"add sp, sp, #4 \n\t"
"sub %0, r0, r1 \n\t"
: "=r" (pc_store_offset) : : "r0", "r1", "memory");
#elif defined(__thumb__)
static int pc_store_offset = -1;
asm volatile(
"@ Enter ARM Mode \n\t"
"adr r2, 1f \n\t"
"bx r2 \n\t"
".ALIGN 4 \n\t"
".ARM \n"
"1: sub sp, sp, #4 \n\t"
"sub r1, pc, #4 \n\t"
"stmia sp, {pc} \n\t"
"ldr r0, [sp] \n\t"
"add sp, sp, #4 \n\t"
"sub %0, r0, r1 \n"
"@ Enter THUMB Mode\n\t"
"adr r2, 2f+1 \n\t"
"bx r2 \n\t"
".THUMB \n"
"2: \n\t"
: "=r" (pc_store_offset) : : "r0", "r1", "r2", "memory");
#else
#error unsupported architecture
#endif
ASSERT(pc_store_offset == 8 || pc_store_offset == 12);
return pc_store_offset;
}
// -----------------------------------------------------------------------------
// Implementation of RelocInfo
const int RelocInfo::kApplyMask = 0;
void RelocInfo::patch_code(byte* instructions, int instruction_count) {
// Patch the code at the current address with the supplied instructions.
UNIMPLEMENTED();
}
// Patch the code at the current PC with a call to the target address.
// Additional guard int3 instructions can be added if required.
void RelocInfo::patch_code_with_call(Address target, int guard_bytes) {
// Patch the code at the current address with a call to the target.
UNIMPLEMENTED();
}
// -----------------------------------------------------------------------------
// Implementation of Operand and MemOperand
// See assembler-arm-inl.h for inlined constructors
Operand::Operand(Handle<Object> handle) {
rm_ = no_reg;
// Verify all Objects referred by code are NOT in new space.
Object* obj = *handle;
ASSERT(!Heap::InNewSpace(obj));
if (obj->IsHeapObject()) {
imm32_ = reinterpret_cast<intptr_t>(handle.location());
rmode_ = RelocInfo::EMBEDDED_OBJECT;
} else {
// no relocation needed
imm32_ = reinterpret_cast<intptr_t>(obj);
rmode_ = RelocInfo::NONE;
}
}
Operand::Operand(Register rm, ShiftOp shift_op, int shift_imm) {
ASSERT(is_uint5(shift_imm));
ASSERT(shift_op != ROR || shift_imm != 0); // use RRX if you mean it
rm_ = rm;
rs_ = no_reg;
shift_op_ = shift_op;
shift_imm_ = shift_imm & 31;
if (shift_op == RRX) {
// encoded as ROR with shift_imm == 0
ASSERT(shift_imm == 0);
shift_op_ = ROR;
shift_imm_ = 0;
}
}
Operand::Operand(Register rm, ShiftOp shift_op, Register rs) {
ASSERT(shift_op != RRX);
rm_ = rm;
rs_ = no_reg;
shift_op_ = shift_op;
rs_ = rs;
}
MemOperand::MemOperand(Register rn, int32_t offset, AddrMode am) {
rn_ = rn;
rm_ = no_reg;
offset_ = offset;
am_ = am;
}
MemOperand::MemOperand(Register rn, Register rm, AddrMode am) {
rn_ = rn;
rm_ = rm;
shift_op_ = LSL;
shift_imm_ = 0;
am_ = am;
}
MemOperand::MemOperand(Register rn, Register rm,
ShiftOp shift_op, int shift_imm, AddrMode am) {
ASSERT(is_uint5(shift_imm));
rn_ = rn;
rm_ = rm;
shift_op_ = shift_op;
shift_imm_ = shift_imm & 31;
am_ = am;
}
// -----------------------------------------------------------------------------
// Implementation of Assembler
// Instruction encoding bits
enum {
H = 1 << 5, // halfword (or byte)
S6 = 1 << 6, // signed (or unsigned)
L = 1 << 20, // load (or store)
S = 1 << 20, // set condition code (or leave unchanged)
W = 1 << 21, // writeback base register (or leave unchanged)
A = 1 << 21, // accumulate in multiply instruction (or not)
B = 1 << 22, // unsigned byte (or word)
N = 1 << 22, // long (or short)
U = 1 << 23, // positive (or negative) offset/index
P = 1 << 24, // offset/pre-indexed addressing (or post-indexed addressing)
I = 1 << 25, // immediate shifter operand (or not)
B4 = 1 << 4,
B5 = 1 << 5,
B7 = 1 << 7,
B8 = 1 << 8,
B12 = 1 << 12,
B16 = 1 << 16,
B20 = 1 << 20,
B21 = 1 << 21,
B22 = 1 << 22,
B23 = 1 << 23,
B24 = 1 << 24,
B25 = 1 << 25,
B26 = 1 << 26,
B27 = 1 << 27,
// Instruction bit masks
RdMask = 15 << 12, // in str instruction
CondMask = 15 << 28,
OpCodeMask = 15 << 21, // in data-processing instructions
Imm24Mask = (1 << 24) - 1,
Off12Mask = (1 << 12) - 1,
// Reserved condition
nv = 15 << 28
};
// add(sp, sp, 4) instruction (aka Pop())
static const Instr kPopInstruction =
al | 4 * B21 | 4 | LeaveCC | I | sp.code() * B16 | sp.code() * B12;
// str(r, MemOperand(sp, 4, NegPreIndex), al) instruction (aka push(r))
// register r is not encoded.
static const Instr kPushRegPattern =
al | B26 | 4 | NegPreIndex | sp.code() * B16;
// ldr(r, MemOperand(sp, 4, PostIndex), al) instruction (aka pop(r))
// register r is not encoded.
static const Instr kPopRegPattern =
al | B26 | L | 4 | PostIndex | sp.code() * B16;
// spare_buffer_
static const int kMinimalBufferSize = 4*KB;
static byte* spare_buffer_ = NULL;
Assembler::Assembler(void* buffer, int buffer_size) {
if (buffer == NULL) {
// do our own buffer management
if (buffer_size <= kMinimalBufferSize) {
buffer_size = kMinimalBufferSize;
if (spare_buffer_ != NULL) {
buffer = spare_buffer_;
spare_buffer_ = NULL;
}
}
if (buffer == NULL) {
buffer_ = NewArray<byte>(buffer_size);
} else {
buffer_ = static_cast<byte*>(buffer);
}
buffer_size_ = buffer_size;
own_buffer_ = true;
} else {
// use externally provided buffer instead
ASSERT(buffer_size > 0);
buffer_ = static_cast<byte*>(buffer);
buffer_size_ = buffer_size;
own_buffer_ = false;
}
// setup buffer pointers
ASSERT(buffer_ != NULL);
pc_ = buffer_;
reloc_info_writer.Reposition(buffer_ + buffer_size, pc_);
num_prinfo_ = 0;
next_buffer_check_ = 0;
no_const_pool_before_ = 0;
last_const_pool_end_ = 0;
last_bound_pos_ = 0;
last_position_ = RelocInfo::kNoPosition;
last_position_is_statement_ = false;
}
Assembler::~Assembler() {
if (own_buffer_) {
if (spare_buffer_ == NULL && buffer_size_ == kMinimalBufferSize) {
spare_buffer_ = buffer_;
} else {
DeleteArray(buffer_);
}
}
}
void Assembler::GetCode(CodeDesc* desc) {
// emit constant pool if necessary
CheckConstPool(true, false);
ASSERT(num_prinfo_ == 0);
// setup desc
desc->buffer = buffer_;
desc->buffer_size = buffer_size_;
desc->instr_size = pc_offset();
desc->reloc_size = (buffer_ + buffer_size_) - reloc_info_writer.pos();
}
void Assembler::Align(int m) {
ASSERT(m >= 4 && IsPowerOf2(m));
while ((pc_offset() & (m - 1)) != 0) {
nop();
}
}
// Labels refer to positions in the (to be) generated code.
// There are bound, linked, and unused labels.
//
// Bound labels refer to known positions in the already
// generated code. pos() is the position the label refers to.
//
// Linked labels refer to unknown positions in the code
// to be generated; pos() is the position of the last
// instruction using the label.
// The link chain is terminated by a negative code position (must be aligned)
const int kEndOfChain = -4;
int Assembler::target_at(int pos) {
Instr instr = instr_at(pos);
ASSERT((instr & 7*B25) == 5*B25); // b, bl, or blx imm24
int imm26 = ((instr & Imm24Mask) << 8) >> 6;
if ((instr & CondMask) == nv && (instr & B24) != 0)
// blx uses bit 24 to encode bit 2 of imm26
imm26 += 2;
return pos + 8 + imm26;
}
void Assembler::target_at_put(int pos, int target_pos) {
int imm26 = target_pos - pos - 8;
Instr instr = instr_at(pos);
ASSERT((instr & 7*B25) == 5*B25); // b, bl, or blx imm24
if ((instr & CondMask) == nv) {
// blx uses bit 24 to encode bit 2 of imm26
ASSERT((imm26 & 1) == 0);
instr = (instr & ~(B24 | Imm24Mask)) | ((imm26 & 2) >> 1)*B24;
} else {
ASSERT((imm26 & 3) == 0);
instr &= ~Imm24Mask;
}
int imm24 = imm26 >> 2;
ASSERT(is_int24(imm24));
instr_at_put(pos, instr | (imm24 & Imm24Mask));
}
void Assembler::print(Label* L) {
if (L->is_unused()) {
PrintF("unused label\n");
} else if (L->is_bound()) {
PrintF("bound label to %d\n", L->pos());
} else if (L->is_linked()) {
Label l = *L;
PrintF("unbound label");
while (l.is_linked()) {
PrintF("@ %d ", l.pos());
Instr instr = instr_at(l.pos());
ASSERT((instr & 7*B25) == 5*B25); // b, bl, or blx
int cond = instr & CondMask;
const char* b;
const char* c;
if (cond == nv) {
b = "blx";
c = "";
} else {
if ((instr & B24) != 0)
b = "bl";
else
b = "b";
switch (cond) {
case eq: c = "eq"; break;
case ne: c = "ne"; break;
case hs: c = "hs"; break;
case lo: c = "lo"; break;
case mi: c = "mi"; break;
case pl: c = "pl"; break;
case vs: c = "vs"; break;
case vc: c = "vc"; break;
case hi: c = "hi"; break;
case ls: c = "ls"; break;
case ge: c = "ge"; break;
case lt: c = "lt"; break;
case gt: c = "gt"; break;
case le: c = "le"; break;
case al: c = ""; break;
default:
c = "";
UNREACHABLE();
}
}
PrintF("%s%s\n", b, c);
next(&l);
}
} else {
PrintF("label in inconsistent state (pos = %d)\n", L->pos_);
}
}
void Assembler::bind_to(Label* L, int pos) {
ASSERT(0 <= pos && pos <= pc_offset()); // must have a valid binding position
while (L->is_linked()) {
int fixup_pos = L->pos();
next(L); // call next before overwriting link with target at fixup_pos
target_at_put(fixup_pos, pos);
}
L->bind_to(pos);
// Keep track of the last bound label so we don't eliminate any instructions
// before a bound label.
if (pos > last_bound_pos_)
last_bound_pos_ = pos;
}
void Assembler::link_to(Label* L, Label* appendix) {
if (appendix->is_linked()) {
if (L->is_linked()) {
// append appendix to L's list
int fixup_pos;
int link = L->pos();
do {
fixup_pos = link;
link = target_at(fixup_pos);
} while (link > 0);
ASSERT(link == kEndOfChain);
target_at_put(fixup_pos, appendix->pos());
} else {
// L is empty, simply use appendix
*L = *appendix;
}
}
appendix->Unuse(); // appendix should not be used anymore
}
void Assembler::bind(Label* L) {
ASSERT(!L->is_bound()); // label can only be bound once
bind_to(L, pc_offset());
}
void Assembler::next(Label* L) {
ASSERT(L->is_linked());
int link = target_at(L->pos());
if (link > 0) {
L->link_to(link);
} else {
ASSERT(link == kEndOfChain);
L->Unuse();
}
}
// Low-level code emission routines depending on the addressing mode
static bool fits_shifter(uint32_t imm32,
uint32_t* rotate_imm,
uint32_t* immed_8,
Instr* instr) {
// imm32 must be unsigned
for (int rot = 0; rot < 16; rot++) {
uint32_t imm8 = (imm32 << 2*rot) | (imm32 >> (32 - 2*rot));
if ((imm8 <= 0xff)) {
*rotate_imm = rot;
*immed_8 = imm8;
return true;
}
}
// if the opcode is mov or mvn and if ~imm32 fits, change the opcode
if (instr != NULL && (*instr & 0xd*B21) == 0xd*B21) {
if (fits_shifter(~imm32, rotate_imm, immed_8, NULL)) {
*instr ^= 0x2*B21;
return true;
}
}
return false;
}
void Assembler::addrmod1(Instr instr,
Register rn,
Register rd,
const Operand& x) {
CheckBuffer();
ASSERT((instr & ~(CondMask | OpCodeMask | S)) == 0);
if (!x.rm_.is_valid()) {
// immediate
uint32_t rotate_imm;
uint32_t immed_8;
if ((x.rmode_ != RelocInfo::NONE &&
x.rmode_ != RelocInfo::EXTERNAL_REFERENCE) ||
!fits_shifter(x.imm32_, &rotate_imm, &immed_8, &instr)) {
// The immediate operand cannot be encoded as a shifter operand, so load
// it first to register ip and change the original instruction to use ip.
// However, if the original instruction is a 'mov rd, x' (not setting the
// condition code), then replace it with a 'ldr rd, [pc]'
RecordRelocInfo(x.rmode_, x.imm32_);
ASSERT(!rn.is(ip)); // rn should never be ip, or will be trashed
Condition cond = static_cast<Condition>(instr & CondMask);
if ((instr & ~CondMask) == 13*B21) { // mov, S not set
ldr(rd, MemOperand(pc, 0), cond);
} else {
ldr(ip, MemOperand(pc, 0), cond);
addrmod1(instr, rn, rd, Operand(ip));
}
return;
}
instr |= I | rotate_imm*B8 | immed_8;
} else if (!x.rs_.is_valid()) {
// immediate shift
instr |= x.shift_imm_*B7 | x.shift_op_ | x.rm_.code();
} else {
// register shift
ASSERT(!rn.is(pc) && !rd.is(pc) && !x.rm_.is(pc) && !x.rs_.is(pc));
instr |= x.rs_.code()*B8 | x.shift_op_ | B4 | x.rm_.code();
}
emit(instr | rn.code()*B16 | rd.code()*B12);
if (rn.is(pc) || x.rm_.is(pc))
// block constant pool emission for one instruction after reading pc
BlockConstPoolBefore(pc_offset() + kInstrSize);
}
void Assembler::addrmod2(Instr instr, Register rd, const MemOperand& x) {
ASSERT((instr & ~(CondMask | B | L)) == B26);
int am = x.am_;
if (!x.rm_.is_valid()) {
// immediate offset
int offset_12 = x.offset_;
if (offset_12 < 0) {
offset_12 = -offset_12;
am ^= U;
}
if (!is_uint12(offset_12)) {
// immediate offset cannot be encoded, load it first to register ip
// rn (and rd in a load) should never be ip, or will be trashed
ASSERT(!x.rn_.is(ip) && ((instr & L) == L || !rd.is(ip)));
mov(ip, Operand(x.offset_), LeaveCC,
static_cast<Condition>(instr & CondMask));
addrmod2(instr, rd, MemOperand(x.rn_, ip, x.am_));
return;
}
ASSERT(offset_12 >= 0); // no masking needed
instr |= offset_12;
} else {
// register offset (shift_imm_ and shift_op_ are 0) or scaled
// register offset the constructors make sure than both shift_imm_
// and shift_op_ are initialized
ASSERT(!x.rm_.is(pc));
instr |= B25 | x.shift_imm_*B7 | x.shift_op_ | x.rm_.code();
}
ASSERT((am & (P|W)) == P || !x.rn_.is(pc)); // no pc base with writeback
emit(instr | am | x.rn_.code()*B16 | rd.code()*B12);
}
void Assembler::addrmod3(Instr instr, Register rd, const MemOperand& x) {
ASSERT((instr & ~(CondMask | L | S6 | H)) == (B4 | B7));
ASSERT(x.rn_.is_valid());
int am = x.am_;
if (!x.rm_.is_valid()) {
// immediate offset
int offset_8 = x.offset_;
if (offset_8 < 0) {
offset_8 = -offset_8;
am ^= U;
}
if (!is_uint8(offset_8)) {
// immediate offset cannot be encoded, load it first to register ip
// rn (and rd in a load) should never be ip, or will be trashed
ASSERT(!x.rn_.is(ip) && ((instr & L) == L || !rd.is(ip)));
mov(ip, Operand(x.offset_), LeaveCC,
static_cast<Condition>(instr & CondMask));
addrmod3(instr, rd, MemOperand(x.rn_, ip, x.am_));
return;
}
ASSERT(offset_8 >= 0); // no masking needed
instr |= B | (offset_8 >> 4)*B8 | (offset_8 & 0xf);
} else if (x.shift_imm_ != 0) {
// scaled register offset not supported, load index first
// rn (and rd in a load) should never be ip, or will be trashed
ASSERT(!x.rn_.is(ip) && ((instr & L) == L || !rd.is(ip)));
mov(ip, Operand(x.rm_, x.shift_op_, x.shift_imm_), LeaveCC,
static_cast<Condition>(instr & CondMask));
addrmod3(instr, rd, MemOperand(x.rn_, ip, x.am_));
return;
} else {
// register offset
ASSERT((am & (P|W)) == P || !x.rm_.is(pc)); // no pc index with writeback
instr |= x.rm_.code();
}
ASSERT((am & (P|W)) == P || !x.rn_.is(pc)); // no pc base with writeback
emit(instr | am | x.rn_.code()*B16 | rd.code()*B12);
}
void Assembler::addrmod4(Instr instr, Register rn, RegList rl) {
ASSERT((instr & ~(CondMask | P | U | W | L)) == B27);
ASSERT(rl != 0);
ASSERT(!rn.is(pc));
emit(instr | rn.code()*B16 | rl);
}
void Assembler::addrmod5(Instr instr, CRegister crd, const MemOperand& x) {
// unindexed addressing is not encoded by this function
ASSERT((instr & ~(CondMask | P | U | N | W | L)) == (B27 | B26));
ASSERT(x.rn_.is_valid() && !x.rm_.is_valid());
int am = x.am_;
int offset_8 = x.offset_;
ASSERT((offset_8 & 3) == 0); // offset must be an aligned word offset
offset_8 >>= 2;
if (offset_8 < 0) {
offset_8 = -offset_8;
am ^= U;
}
ASSERT(is_uint8(offset_8)); // unsigned word offset must fit in a byte
ASSERT((am & (P|W)) == P || !x.rn_.is(pc)); // no pc base with writeback
// post-indexed addressing requires W == 1; different than in addrmod2/3
if ((am & P) == 0)
am |= W;
ASSERT(offset_8 >= 0); // no masking needed
emit(instr | am | x.rn_.code()*B16 | crd.code()*B12 | offset_8);
}
int Assembler::branch_offset(Label* L, bool jump_elimination_allowed) {
int target_pos;
if (L->is_bound()) {
target_pos = L->pos();
} else {
if (L->is_linked()) {
target_pos = L->pos(); // L's link
} else {
target_pos = kEndOfChain;
}
L->link_to(pc_offset());
}
// Block the emission of the constant pool, since the branch instruction must
// be emitted at the pc offset recorded by the label
BlockConstPoolBefore(pc_offset() + kInstrSize);
return target_pos - pc_offset() - 8;
}
// Branch instructions
void Assembler::b(int branch_offset, Condition cond) {
ASSERT((branch_offset & 3) == 0);
int imm24 = branch_offset >> 2;
ASSERT(is_int24(imm24));
emit(cond | B27 | B25 | (imm24 & Imm24Mask));
if (cond == al)
// dead code is a good location to emit the constant pool
CheckConstPool(false, false);
}
void Assembler::bl(int branch_offset, Condition cond) {
ASSERT((branch_offset & 3) == 0);
int imm24 = branch_offset >> 2;
ASSERT(is_int24(imm24));
emit(cond | B27 | B25 | B24 | (imm24 & Imm24Mask));
}
void Assembler::blx(int branch_offset) { // v5 and above
ASSERT((branch_offset & 1) == 0);
int h = ((branch_offset & 2) >> 1)*B24;
int imm24 = branch_offset >> 2;
ASSERT(is_int24(imm24));
emit(15 << 28 | B27 | B25 | h | (imm24 & Imm24Mask));
}
void Assembler::blx(Register target, Condition cond) { // v5 and above
ASSERT(!target.is(pc));
emit(cond | B24 | B21 | 15*B16 | 15*B12 | 15*B8 | 3*B4 | target.code());
}
void Assembler::bx(Register target, Condition cond) { // v5 and above, plus v4t
ASSERT(!target.is(pc)); // use of pc is actually allowed, but discouraged
emit(cond | B24 | B21 | 15*B16 | 15*B12 | 15*B8 | B4 | target.code());
}
// Data-processing instructions
void Assembler::and_(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 0*B21 | s, src1, dst, src2);
}
void Assembler::eor(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 1*B21 | s, src1, dst, src2);
}
void Assembler::sub(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 2*B21 | s, src1, dst, src2);
}
void Assembler::rsb(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 3*B21 | s, src1, dst, src2);
}
void Assembler::add(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 4*B21 | s, src1, dst, src2);
// Eliminate pattern: push(r), pop()
// str(src, MemOperand(sp, 4, NegPreIndex), al);
// add(sp, sp, Operand(kPointerSize));
// Both instructions can be eliminated.
int pattern_size = 2 * kInstrSize;
if (FLAG_push_pop_elimination &&
last_bound_pos_ <= (pc_offset() - pattern_size) &&
reloc_info_writer.last_pc() <= (pc_ - pattern_size) &&
// pattern
instr_at(pc_ - 1 * kInstrSize) == kPopInstruction &&
(instr_at(pc_ - 2 * kInstrSize) & ~RdMask) == kPushRegPattern) {
pc_ -= 2 * kInstrSize;
if (FLAG_print_push_pop_elimination) {
PrintF("%x push(reg)/pop() eliminated\n", pc_offset());
}
}
}
void Assembler::adc(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 5*B21 | s, src1, dst, src2);
}
void Assembler::sbc(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 6*B21 | s, src1, dst, src2);
}
void Assembler::rsc(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 7*B21 | s, src1, dst, src2);
}
void Assembler::tst(Register src1, const Operand& src2, Condition cond) {
addrmod1(cond | 8*B21 | S, src1, r0, src2);
}
void Assembler::teq(Register src1, const Operand& src2, Condition cond) {
addrmod1(cond | 9*B21 | S, src1, r0, src2);
}
void Assembler::cmp(Register src1, const Operand& src2, Condition cond) {
addrmod1(cond | 10*B21 | S, src1, r0, src2);
}
void Assembler::cmn(Register src1, const Operand& src2, Condition cond) {
addrmod1(cond | 11*B21 | S, src1, r0, src2);
}
void Assembler::orr(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 12*B21 | s, src1, dst, src2);
}
void Assembler::mov(Register dst, const Operand& src, SBit s, Condition cond) {
addrmod1(cond | 13*B21 | s, r0, dst, src);
}
void Assembler::bic(Register dst, Register src1, const Operand& src2,
SBit s, Condition cond) {
addrmod1(cond | 14*B21 | s, src1, dst, src2);
}
void Assembler::mvn(Register dst, const Operand& src, SBit s, Condition cond) {
addrmod1(cond | 15*B21 | s, r0, dst, src);
}
// Multiply instructions
void Assembler::mla(Register dst, Register src1, Register src2, Register srcA,
SBit s, Condition cond) {
ASSERT(!dst.is(pc) && !src1.is(pc) && !src2.is(pc) && !srcA.is(pc));
ASSERT(!dst.is(src1));
emit(cond | A | s | dst.code()*B16 | srcA.code()*B12 |
src2.code()*B8 | B7 | B4 | src1.code());
}
void Assembler::mul(Register dst, Register src1, Register src2,
SBit s, Condition cond) {
ASSERT(!dst.is(pc) && !src1.is(pc) && !src2.is(pc));
ASSERT(!dst.is(src1));
emit(cond | s | dst.code()*B16 | src2.code()*B8 | B7 | B4 | src1.code());
}
void Assembler::smlal(Register dstL,
Register dstH,
Register src1,
Register src2,
SBit s,
Condition cond) {
ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
emit(cond | B23 | B22 | A | s | dstH.code()*B16 | dstL.code()*B12 |
src2.code()*B8 | B7 | B4 | src1.code());
}
void Assembler::smull(Register dstL,
Register dstH,
Register src1,
Register src2,
SBit s,
Condition cond) {
ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
emit(cond | B23 | B22 | s | dstH.code()*B16 | dstL.code()*B12 |
src2.code()*B8 | B7 | B4 | src1.code());
}
void Assembler::umlal(Register dstL,
Register dstH,
Register src1,
Register src2,
SBit s,
Condition cond) {
ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
emit(cond | B23 | A | s | dstH.code()*B16 | dstL.code()*B12 |
src2.code()*B8 | B7 | B4 | src1.code());
}
void Assembler::umull(Register dstL,
Register dstH,
Register src1,
Register src2,
SBit s,
Condition cond) {
ASSERT(!dstL.is(pc) && !dstH.is(pc) && !src1.is(pc) && !src2.is(pc));
ASSERT(!dstL.is(dstH) && !dstH.is(src1) && !src1.is(dstL));
emit(cond | B23 | s | dstH.code()*B16 | dstL.code()*B12 |
src2.code()*B8 | B7 | B4 | src1.code());
}
// Miscellaneous arithmetic instructions
void Assembler::clz(Register dst, Register src, Condition cond) {
// v5 and above.
ASSERT(!dst.is(pc) && !src.is(pc));
emit(cond | B24 | B22 | B21 | 15*B16 | dst.code()*B12 |
15*B8 | B4 | src.code());
}
// Status register access instructions
void Assembler::mrs(Register dst, SRegister s, Condition cond) {
ASSERT(!dst.is(pc));
emit(cond | B24 | s | 15*B16 | dst.code()*B12);
}
void Assembler::msr(SRegisterFieldMask fields, const Operand& src,
Condition cond) {
ASSERT(fields >= B16 && fields < B20); // at least one field set
Instr instr;
if (!src.rm_.is_valid()) {
// immediate
uint32_t rotate_imm;
uint32_t immed_8;
if ((src.rmode_ != RelocInfo::NONE &&
src.rmode_ != RelocInfo::EXTERNAL_REFERENCE)||
!fits_shifter(src.imm32_, &rotate_imm, &immed_8, NULL)) {
// immediate operand cannot be encoded, load it first to register ip
RecordRelocInfo(src.rmode_, src.imm32_);
ldr(ip, MemOperand(pc, 0), cond);
msr(fields, Operand(ip), cond);
return;
}
instr = I | rotate_imm*B8 | immed_8;
} else {
ASSERT(!src.rs_.is_valid() && src.shift_imm_ == 0); // only rm allowed
instr = src.rm_.code();
}
emit(cond | instr | B24 | B21 | fields | 15*B12);
}
// Load/Store instructions
void Assembler::ldr(Register dst, const MemOperand& src, Condition cond) {
addrmod2(cond | B26 | L, dst, src);
// Eliminate pattern: push(r), pop(r)
// str(r, MemOperand(sp, 4, NegPreIndex), al)
// ldr(r, MemOperand(sp, 4, PostIndex), al)
// Both instructions can be eliminated.
int pattern_size = 2 * kInstrSize;
if (FLAG_push_pop_elimination &&
last_bound_pos_ <= (pc_offset() - pattern_size) &&
reloc_info_writer.last_pc() <= (pc_ - pattern_size) &&
// pattern
instr_at(pc_ - 1 * kInstrSize) == (kPopRegPattern | dst.code() * B12) &&
instr_at(pc_ - 2 * kInstrSize) == (kPushRegPattern | dst.code() * B12)) {
pc_ -= 2 * kInstrSize;
if (FLAG_print_push_pop_elimination) {
PrintF("%x push/pop (same reg) eliminated\n", pc_offset());
}
}
}
void Assembler::str(Register src, const MemOperand& dst, Condition cond) {
addrmod2(cond | B26, src, dst);
// Eliminate pattern: pop(), push(r)
// add sp, sp, #4 LeaveCC, al; str r, [sp, #-4], al
// -> str r, [sp, 0], al
int pattern_size = 2 * kInstrSize;
if (FLAG_push_pop_elimination &&
last_bound_pos_ <= (pc_offset() - pattern_size) &&
reloc_info_writer.last_pc() <= (pc_ - pattern_size) &&
instr_at(pc_ - 1 * kInstrSize) == (kPushRegPattern | src.code() * B12) &&
instr_at(pc_ - 2 * kInstrSize) == kPopInstruction) {
pc_ -= 2 * kInstrSize;
emit(al | B26 | 0 | Offset | sp.code() * B16 | src.code() * B12);
if (FLAG_print_push_pop_elimination) {
PrintF("%x pop()/push(reg) eliminated\n", pc_offset());
}
}
}
void Assembler::ldrb(Register dst, const MemOperand& src, Condition cond) {
addrmod2(cond | B26 | B | L, dst, src);
}
void Assembler::strb(Register src, const MemOperand& dst, Condition cond) {
addrmod2(cond | B26 | B, src, dst);
}
void Assembler::ldrh(Register dst, const MemOperand& src, Condition cond) {
addrmod3(cond | L | B7 | H | B4, dst, src);
}
void Assembler::strh(Register src, const MemOperand& dst, Condition cond) {
addrmod3(cond | B7 | H | B4, src, dst);
}
void Assembler::ldrsb(Register dst, const MemOperand& src, Condition cond) {
addrmod3(cond | L | B7 | S6 | B4, dst, src);
}
void Assembler::ldrsh(Register dst, const MemOperand& src, Condition cond) {
addrmod3(cond | L | B7 | S6 | H | B4, dst, src);
}
// Load/Store multiple instructions
void Assembler::ldm(BlockAddrMode am,
Register base,
RegList dst,
Condition cond) {
// ABI stack constraint: ldmxx base, {..sp..} base != sp is not restartable
ASSERT(base.is(sp) || (dst & sp.bit()) == 0);
addrmod4(cond | B27 | am | L, base, dst);
// emit the constant pool after a function return implemented by ldm ..{..pc}
if (cond == al && (dst & pc.bit()) != 0) {
// There is a slight chance that the ldm instruction was actually a call,
// in which case it would be wrong to return into the constant pool; we
// recognize this case by checking if the emission of the pool was blocked
// at the pc of the ldm instruction by a mov lr, pc instruction; if this is
// the case, we emit a jump over the pool.
CheckConstPool(true, no_const_pool_before_ == pc_offset() - kInstrSize);
}
}
void Assembler::stm(BlockAddrMode am,
Register base,
RegList src,
Condition cond) {
addrmod4(cond | B27 | am, base, src);
}
// Semaphore instructions
void Assembler::swp(Register dst, Register src, Register base, Condition cond) {
ASSERT(!dst.is(pc) && !src.is(pc) && !base.is(pc));
ASSERT(!dst.is(base) && !src.is(base));
emit(cond | P | base.code()*B16 | dst.code()*B12 |
B7 | B4 | src.code());
}
void Assembler::swpb(Register dst,
Register src,
Register base,
Condition cond) {
ASSERT(!dst.is(pc) && !src.is(pc) && !base.is(pc));
ASSERT(!dst.is(base) && !src.is(base));
emit(cond | P | B | base.code()*B16 | dst.code()*B12 |
B7 | B4 | src.code());
}
// Exception-generating instructions and debugging support
void Assembler::stop(const char* msg) {
#if !defined(__arm__)
// The simulator handles these special instructions and stops execution.
emit(15 << 28 | ((intptr_t) msg));
#else
// Just issue a simple break instruction for now. Alternatively we could use
// the swi(0x9f0001) instruction on Linux.
bkpt(0);
#endif
}
void Assembler::bkpt(uint32_t imm16) { // v5 and above
ASSERT(is_uint16(imm16));
emit(al | B24 | B21 | (imm16 >> 4)*B8 | 7*B4 | (imm16 & 0xf));
}
void Assembler::swi(uint32_t imm24, Condition cond) {
ASSERT(is_uint24(imm24));
emit(cond | 15*B24 | imm24);
}
// Coprocessor instructions
void Assembler::cdp(Coprocessor coproc,
int opcode_1,
CRegister crd,
CRegister crn,
CRegister crm,
int opcode_2,
Condition cond) {
ASSERT(is_uint4(opcode_1) && is_uint3(opcode_2));
emit(cond | B27 | B26 | B25 | (opcode_1 & 15)*B20 | crn.code()*B16 |
crd.code()*B12 | coproc*B8 | (opcode_2 & 7)*B5 | crm.code());
}
void Assembler::cdp2(Coprocessor coproc,
int opcode_1,
CRegister crd,
CRegister crn,
CRegister crm,
int opcode_2) { // v5 and above
cdp(coproc, opcode_1, crd, crn, crm, opcode_2, static_cast<Condition>(nv));
}
void Assembler::mcr(Coprocessor coproc,
int opcode_1,
Register rd,
CRegister crn,
CRegister crm,
int opcode_2,
Condition cond) {
ASSERT(is_uint3(opcode_1) && is_uint3(opcode_2));
emit(cond | B27 | B26 | B25 | (opcode_1 & 7)*B21 | crn.code()*B16 |
rd.code()*B12 | coproc*B8 | (opcode_2 & 7)*B5 | B4 | crm.code());
}
void Assembler::mcr2(Coprocessor coproc,
int opcode_1,
Register rd,
CRegister crn,
CRegister crm,
int opcode_2) { // v5 and above
mcr(coproc, opcode_1, rd, crn, crm, opcode_2, static_cast<Condition>(nv));
}
void Assembler::mrc(Coprocessor coproc,
int opcode_1,
Register rd,
CRegister crn,
CRegister crm,
int opcode_2,
Condition cond) {
ASSERT(is_uint3(opcode_1) && is_uint3(opcode_2));
emit(cond | B27 | B26 | B25 | (opcode_1 & 7)*B21 | L | crn.code()*B16 |
rd.code()*B12 | coproc*B8 | (opcode_2 & 7)*B5 | B4 | crm.code());
}
void Assembler::mrc2(Coprocessor coproc,
int opcode_1,
Register rd,
CRegister crn,
CRegister crm,
int opcode_2) { // v5 and above
mrc(coproc, opcode_1, rd, crn, crm, opcode_2, static_cast<Condition>(nv));
}
void Assembler::ldc(Coprocessor coproc,
CRegister crd,
const MemOperand& src,
LFlag l,
Condition cond) {
addrmod5(cond | B27 | B26 | l | L | coproc*B8, crd, src);
}
void Assembler::ldc(Coprocessor coproc,
CRegister crd,
Register rn,
int option,
LFlag l,
Condition cond) {
// unindexed addressing
ASSERT(is_uint8(option));
emit(cond | B27 | B26 | U | l | L | rn.code()*B16 | crd.code()*B12 |
coproc*B8 | (option & 255));
}
void Assembler::ldc2(Coprocessor coproc,
CRegister crd,
const MemOperand& src,
LFlag l) { // v5 and above
ldc(coproc, crd, src, l, static_cast<Condition>(nv));
}
void Assembler::ldc2(Coprocessor coproc,
CRegister crd,
Register rn,
int option,
LFlag l) { // v5 and above
ldc(coproc, crd, rn, option, l, static_cast<Condition>(nv));
}
void Assembler::stc(Coprocessor coproc,
CRegister crd,
const MemOperand& dst,
LFlag l,
Condition cond) {
addrmod5(cond | B27 | B26 | l | coproc*B8, crd, dst);
}
void Assembler::stc(Coprocessor coproc,
CRegister crd,
Register rn,
int option,
LFlag l,
Condition cond) {
// unindexed addressing
ASSERT(is_uint8(option));
emit(cond | B27 | B26 | U | l | rn.code()*B16 | crd.code()*B12 |
coproc*B8 | (option & 255));
}
void Assembler::stc2(Coprocessor
coproc, CRegister crd,
const MemOperand& dst,
LFlag l) { // v5 and above
stc(coproc, crd, dst, l, static_cast<Condition>(nv));
}
void Assembler::stc2(Coprocessor coproc,
CRegister crd,
Register rn,
int option,
LFlag l) { // v5 and above
stc(coproc, crd, rn, option, l, static_cast<Condition>(nv));
}
// Pseudo instructions
void Assembler::lea(Register dst,
const MemOperand& x,
SBit s,
Condition cond) {
int am = x.am_;
if (!x.rm_.is_valid()) {
// immediate offset
if ((am & P) == 0) // post indexing
mov(dst, Operand(x.rn_), s, cond);
else if ((am & U) == 0) // negative indexing
sub(dst, x.rn_, Operand(x.offset_), s, cond);
else
add(dst, x.rn_, Operand(x.offset_), s, cond);
} else {
// Register offset (shift_imm_ and shift_op_ are 0) or scaled
// register offset the constructors make sure than both shift_imm_
// and shift_op_ are initialized.
ASSERT(!x.rm_.is(pc));
if ((am & P) == 0) // post indexing
mov(dst, Operand(x.rn_), s, cond);
else if ((am & U) == 0) // negative indexing
sub(dst, x.rn_, Operand(x.rm_, x.shift_op_, x.shift_imm_), s, cond);
else
add(dst, x.rn_, Operand(x.rm_, x.shift_op_, x.shift_imm_), s, cond);
}
}
// Debugging
void Assembler::RecordComment(const char* msg) {
if (FLAG_debug_code) {
CheckBuffer();
RecordRelocInfo(RelocInfo::COMMENT, reinterpret_cast<intptr_t>(msg));
}
}
void Assembler::RecordPosition(int pos) {
if (pos == RelocInfo::kNoPosition) return;
ASSERT(pos >= 0);
if (pos == last_position_) return;
CheckBuffer();
RecordRelocInfo(RelocInfo::POSITION, pos);
last_position_ = pos;
last_position_is_statement_ = false;
}
void Assembler::RecordStatementPosition(int pos) {
if (pos == last_position_) return;
CheckBuffer();
RecordRelocInfo(RelocInfo::STATEMENT_POSITION, pos);
last_position_ = pos;
last_position_is_statement_ = true;
}
void Assembler::GrowBuffer() {
if (!own_buffer_) FATAL("external code buffer is too small");
// compute new buffer size
CodeDesc desc; // the new buffer
if (buffer_size_ < 4*KB) {
desc.buffer_size = 4*KB;
} else if (buffer_size_ < 1*MB) {
desc.buffer_size = 2*buffer_size_;
} else {
desc.buffer_size = buffer_size_ + 1*MB;
}
CHECK_GT(desc.buffer_size, 0); // no overflow
// setup new buffer
desc.buffer = NewArray<byte>(desc.buffer_size);
desc.instr_size = pc_offset();
desc.reloc_size = (buffer_ + buffer_size_) - reloc_info_writer.pos();
// copy the data
int pc_delta = desc.buffer - buffer_;
int rc_delta = (desc.buffer + desc.buffer_size) - (buffer_ + buffer_size_);
memmove(desc.buffer, buffer_, desc.instr_size);
memmove(reloc_info_writer.pos() + rc_delta,
reloc_info_writer.pos(), desc.reloc_size);
// switch buffers
DeleteArray(buffer_);
buffer_ = desc.buffer;
buffer_size_ = desc.buffer_size;
pc_ += pc_delta;
reloc_info_writer.Reposition(reloc_info_writer.pos() + rc_delta,
reloc_info_writer.last_pc() + pc_delta);
// none of our relocation types are pc relative pointing outside the code
// buffer nor pc absolute pointing inside the code buffer, so there is no need
// to relocate any emitted relocation entries
// relocate pending relocation entries
for (int i = 0; i < num_prinfo_; i++) {
RelocInfo& rinfo = prinfo_[i];
ASSERT(rinfo.rmode() != RelocInfo::COMMENT &&
rinfo.rmode() != RelocInfo::POSITION);
rinfo.set_pc(rinfo.pc() + pc_delta);
}
}
void Assembler::RecordRelocInfo(RelocInfo::Mode rmode, intptr_t data) {
RelocInfo rinfo(pc_, rmode, data); // we do not try to reuse pool constants
if (rmode >= RelocInfo::COMMENT && rmode <= RelocInfo::STATEMENT_POSITION) {
// adjust code for new modes
ASSERT(RelocInfo::IsComment(rmode) || RelocInfo::IsPosition(rmode));
// these modes do not need an entry in the constant pool
} else {
ASSERT(num_prinfo_ < kMaxNumPRInfo);
prinfo_[num_prinfo_++] = rinfo;
// Make sure the constant pool is not emitted in place of the next
// instruction for which we just recorded relocation info
BlockConstPoolBefore(pc_offset() + kInstrSize);
}
if (rinfo.rmode() != RelocInfo::NONE) {
// Don't record external references unless the heap will be serialized.
if (rmode == RelocInfo::EXTERNAL_REFERENCE &&
!Serializer::enabled() &&
!FLAG_debug_code) {
return;
}
ASSERT(buffer_space() >= kMaxRelocSize); // too late to grow buffer here
reloc_info_writer.Write(&rinfo);
}
}
void Assembler::CheckConstPool(bool force_emit, bool require_jump) {
// Calculate the offset of the next check. It will be overwritten
// when a const pool is generated or when const pools are being
// blocked for a specific range.
next_buffer_check_ = pc_offset() + kCheckConstInterval;
// There is nothing to do if there are no pending relocation info entries
if (num_prinfo_ == 0) return;
// We emit a constant pool at regular intervals of about kDistBetweenPools
// or when requested by parameter force_emit (e.g. after each function).
// We prefer not to emit a jump unless the max distance is reached or if we
// are running low on slots, which can happen if a lot of constants are being
// emitted (e.g. --debug-code and many static references).
int dist = pc_offset() - last_const_pool_end_;
if (!force_emit && dist < kMaxDistBetweenPools &&
(require_jump || dist < kDistBetweenPools) &&
// TODO(1236125): Cleanup the "magic" number below. We know that
// the code generation will test every kCheckConstIntervalInst.
// Thus we are safe as long as we generate less than 7 constant
// entries per instruction.
(num_prinfo_ < (kMaxNumPRInfo - (7 * kCheckConstIntervalInst)))) {
return;
}
// If we did not return by now, we need to emit the constant pool soon.
// However, some small sequences of instructions must not be broken up by the
// insertion of a constant pool; such sequences are protected by setting
// no_const_pool_before_, which is checked here. Also, recursive calls to
// CheckConstPool are blocked by no_const_pool_before_.
if (pc_offset() < no_const_pool_before_) {
// Emission is currently blocked; make sure we try again as soon as possible
next_buffer_check_ = no_const_pool_before_;
// Something is wrong if emission is forced and blocked at the same time
ASSERT(!force_emit);
return;
}
int jump_instr = require_jump ? kInstrSize : 0;
// Check that the code buffer is large enough before emitting the constant
// pool and relocation information (include the jump over the pool and the
// constant pool marker).
int max_needed_space =
jump_instr + kInstrSize + num_prinfo_*(kInstrSize + kMaxRelocSize);
while (buffer_space() <= (max_needed_space + kGap)) GrowBuffer();
// Block recursive calls to CheckConstPool
BlockConstPoolBefore(pc_offset() + jump_instr + kInstrSize +
num_prinfo_*kInstrSize);
// Don't bother to check for the emit calls below.
next_buffer_check_ = no_const_pool_before_;
// Emit jump over constant pool if necessary
Label after_pool;
if (require_jump) b(&after_pool);
RecordComment("[ Constant Pool");
// Put down constant pool marker
// "Undefined instruction" as specified by A3.1 Instruction set encoding
emit(0x03000000 | num_prinfo_);
// Emit constant pool entries
for (int i = 0; i < num_prinfo_; i++) {
RelocInfo& rinfo = prinfo_[i];
ASSERT(rinfo.rmode() != RelocInfo::COMMENT &&
rinfo.rmode() != RelocInfo::POSITION &&
rinfo.rmode() != RelocInfo::STATEMENT_POSITION);
Instr instr = instr_at(rinfo.pc());
// Instruction to patch must be a ldr/str [pc, #offset]
// P and U set, B and W clear, Rn == pc, offset12 still 0
ASSERT((instr & (7*B25 | P | U | B | W | 15*B16 | Off12Mask)) ==
(2*B25 | P | U | pc.code()*B16));
int delta = pc_ - rinfo.pc() - 8;
ASSERT(delta >= -4); // instr could be ldr pc, [pc, #-4] followed by targ32
if (delta < 0) {
instr &= ~U;
delta = -delta;
}
ASSERT(is_uint12(delta));
instr_at_put(rinfo.pc(), instr + delta);
emit(rinfo.data());
}
num_prinfo_ = 0;
last_const_pool_end_ = pc_offset();
RecordComment("]");
if (after_pool.is_linked()) {
bind(&after_pool);
}
// Since a constant pool was just emitted, move the check offset forward by
// the standard interval.
next_buffer_check_ = pc_offset() + kCheckConstInterval;
}
} } // namespace v8::internal
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