// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/v8.h"
#if V8_TARGET_ARCH_ARM
#include "src/code-stubs.h"
#include "src/cpu-profiler.h"
#include "src/log.h"
#include "src/macro-assembler.h"
#include "src/regexp-macro-assembler.h"
#include "src/regexp-stack.h"
#include "src/unicode.h"
#include "src/arm/regexp-macro-assembler-arm.h"
namespace v8 {
namespace internal {
#ifndef V8_INTERPRETED_REGEXP
/*
* This assembler uses the following register assignment convention
* - r4 : Temporarily stores the index of capture start after a matching pass
* for a global regexp.
* - r5 : Pointer to current code object (Code*) including heap object tag.
* - r6 : Current position in input, as negative offset from end of string.
* Please notice that this is the byte offset, not the character offset!
* - r7 : Currently loaded character. Must be loaded using
* LoadCurrentCharacter before using any of the dispatch methods.
* - r8 : Points to tip of backtrack stack
* - r9 : Unused, might be used by C code and expected unchanged.
* - r10 : End of input (points to byte after last character in input).
* - r11 : Frame pointer. Used to access arguments, local variables and
* RegExp registers.
* - r12 : IP register, used by assembler. Very volatile.
* - r13/sp : Points to tip of C stack.
*
* The remaining registers are free for computations.
* Each call to a public method should retain this convention.
*
* The stack will have the following structure:
* - fp[56] Isolate* isolate (address of the current isolate)
* - fp[52] direct_call (if 1, direct call from JavaScript code,
* if 0, call through the runtime system).
* - fp[48] stack_area_base (high end of the memory area to use as
* backtracking stack).
* - fp[44] capture array size (may fit multiple sets of matches)
* - fp[40] int* capture_array (int[num_saved_registers_], for output).
* - fp[36] secondary link/return address used by native call.
* --- sp when called ---
* - fp[32] return address (lr).
* - fp[28] old frame pointer (r11).
* - fp[0..24] backup of registers r4..r10.
* --- frame pointer ----
* - fp[-4] end of input (address of end of string).
* - fp[-8] start of input (address of first character in string).
* - fp[-12] start index (character index of start).
* - fp[-16] void* input_string (location of a handle containing the string).
* - fp[-20] success counter (only for global regexps to count matches).
* - fp[-24] Offset of location before start of input (effectively character
* position -1). Used to initialize capture registers to a
* non-position.
* - fp[-28] At start (if 1, we are starting at the start of the
* string, otherwise 0)
* - fp[-32] register 0 (Only positions must be stored in the first
* - register 1 num_saved_registers_ registers)
* - ...
* - register num_registers-1
* --- sp ---
*
* The first num_saved_registers_ registers are initialized to point to
* "character -1" in the string (i.e., char_size() bytes before the first
* character of the string). The remaining registers start out as garbage.
*
* The data up to the return address must be placed there by the calling
* code and the remaining arguments are passed in registers, e.g. by calling the
* code entry as cast to a function with the signature:
* int (*match)(String* input_string,
* int start_index,
* Address start,
* Address end,
* Address secondary_return_address, // Only used by native call.
* int* capture_output_array,
* byte* stack_area_base,
* bool direct_call = false)
* The call is performed by NativeRegExpMacroAssembler::Execute()
* (in regexp-macro-assembler.cc) via the CALL_GENERATED_REGEXP_CODE macro
* in arm/simulator-arm.h.
* When calling as a non-direct call (i.e., from C++ code), the return address
* area is overwritten with the LR register by the RegExp code. When doing a
* direct call from generated code, the return address is placed there by
* the calling code, as in a normal exit frame.
*/
#define __ ACCESS_MASM(masm_)
RegExpMacroAssemblerARM::RegExpMacroAssemblerARM(
Mode mode,
int registers_to_save,
Zone* zone)
: NativeRegExpMacroAssembler(zone),
masm_(new MacroAssembler(zone->isolate(), NULL, kRegExpCodeSize)),
mode_(mode),
num_registers_(registers_to_save),
num_saved_registers_(registers_to_save),
entry_label_(),
start_label_(),
success_label_(),
backtrack_label_(),
exit_label_() {
DCHECK_EQ(0, registers_to_save % 2);
__ jmp(&entry_label_); // We'll write the entry code later.
__ bind(&start_label_); // And then continue from here.
}
RegExpMacroAssemblerARM::~RegExpMacroAssemblerARM() {
delete masm_;
// Unuse labels in case we throw away the assembler without calling GetCode.
entry_label_.Unuse();
start_label_.Unuse();
success_label_.Unuse();
backtrack_label_.Unuse();
exit_label_.Unuse();
check_preempt_label_.Unuse();
stack_overflow_label_.Unuse();
}
int RegExpMacroAssemblerARM::stack_limit_slack() {
return RegExpStack::kStackLimitSlack;
}
void RegExpMacroAssemblerARM::AdvanceCurrentPosition(int by) {
if (by != 0) {
__ add(current_input_offset(),
current_input_offset(), Operand(by * char_size()));
}
}
void RegExpMacroAssemblerARM::AdvanceRegister(int reg, int by) {
DCHECK(reg >= 0);
DCHECK(reg < num_registers_);
if (by != 0) {
__ ldr(r0, register_location(reg));
__ add(r0, r0, Operand(by));
__ str(r0, register_location(reg));
}
}
void RegExpMacroAssemblerARM::Backtrack() {
CheckPreemption();
// Pop Code* offset from backtrack stack, add Code* and jump to location.
Pop(r0);
__ add(pc, r0, Operand(code_pointer()));
}
void RegExpMacroAssemblerARM::Bind(Label* label) {
__ bind(label);
}
void RegExpMacroAssemblerARM::CheckCharacter(uint32_t c, Label* on_equal) {
__ cmp(current_character(), Operand(c));
BranchOrBacktrack(eq, on_equal);
}
void RegExpMacroAssemblerARM::CheckCharacterGT(uc16 limit, Label* on_greater) {
__ cmp(current_character(), Operand(limit));
BranchOrBacktrack(gt, on_greater);
}
void RegExpMacroAssemblerARM::CheckAtStart(Label* on_at_start) {
Label not_at_start;
// Did we start the match at the start of the string at all?
__ ldr(r0, MemOperand(frame_pointer(), kStartIndex));
__ cmp(r0, Operand::Zero());
BranchOrBacktrack(ne, ¬_at_start);
// If we did, are we still at the start of the input?
__ ldr(r1, MemOperand(frame_pointer(), kInputStart));
__ add(r0, end_of_input_address(), Operand(current_input_offset()));
__ cmp(r0, r1);
BranchOrBacktrack(eq, on_at_start);
__ bind(¬_at_start);
}
void RegExpMacroAssemblerARM::CheckNotAtStart(Label* on_not_at_start) {
// Did we start the match at the start of the string at all?
__ ldr(r0, MemOperand(frame_pointer(), kStartIndex));
__ cmp(r0, Operand::Zero());
BranchOrBacktrack(ne, on_not_at_start);
// If we did, are we still at the start of the input?
__ ldr(r1, MemOperand(frame_pointer(), kInputStart));
__ add(r0, end_of_input_address(), Operand(current_input_offset()));
__ cmp(r0, r1);
BranchOrBacktrack(ne, on_not_at_start);
}
void RegExpMacroAssemblerARM::CheckCharacterLT(uc16 limit, Label* on_less) {
__ cmp(current_character(), Operand(limit));
BranchOrBacktrack(lt, on_less);
}
void RegExpMacroAssemblerARM::CheckGreedyLoop(Label* on_equal) {
__ ldr(r0, MemOperand(backtrack_stackpointer(), 0));
__ cmp(current_input_offset(), r0);
__ add(backtrack_stackpointer(),
backtrack_stackpointer(), Operand(kPointerSize), LeaveCC, eq);
BranchOrBacktrack(eq, on_equal);
}
void RegExpMacroAssemblerARM::CheckNotBackReferenceIgnoreCase(
int start_reg,
Label* on_no_match) {
Label fallthrough;
__ ldr(r0, register_location(start_reg)); // Index of start of capture
__ ldr(r1, register_location(start_reg + 1)); // Index of end of capture
__ sub(r1, r1, r0, SetCC); // Length of capture.
// If length is zero, either the capture is empty or it is not participating.
// In either case succeed immediately.
__ b(eq, &fallthrough);
// Check that there are enough characters left in the input.
__ cmn(r1, Operand(current_input_offset()));
BranchOrBacktrack(gt, on_no_match);
if (mode_ == LATIN1) {
Label success;
Label fail;
Label loop_check;
// r0 - offset of start of capture
// r1 - length of capture
__ add(r0, r0, Operand(end_of_input_address()));
__ add(r2, end_of_input_address(), Operand(current_input_offset()));
__ add(r1, r0, Operand(r1));
// r0 - Address of start of capture.
// r1 - Address of end of capture
// r2 - Address of current input position.
Label loop;
__ bind(&loop);
__ ldrb(r3, MemOperand(r0, char_size(), PostIndex));
__ ldrb(r4, MemOperand(r2, char_size(), PostIndex));
__ cmp(r4, r3);
__ b(eq, &loop_check);
// Mismatch, try case-insensitive match (converting letters to lower-case).
__ orr(r3, r3, Operand(0x20)); // Convert capture character to lower-case.
__ orr(r4, r4, Operand(0x20)); // Also convert input character.
__ cmp(r4, r3);
__ b(ne, &fail);
__ sub(r3, r3, Operand('a'));
__ cmp(r3, Operand('z' - 'a')); // Is r3 a lowercase letter?
__ b(ls, &loop_check); // In range 'a'-'z'.
// Latin-1: Check for values in range [224,254] but not 247.
__ sub(r3, r3, Operand(224 - 'a'));
__ cmp(r3, Operand(254 - 224));
__ b(hi, &fail); // Weren't Latin-1 letters.
__ cmp(r3, Operand(247 - 224)); // Check for 247.
__ b(eq, &fail);
__ bind(&loop_check);
__ cmp(r0, r1);
__ b(lt, &loop);
__ jmp(&success);
__ bind(&fail);
BranchOrBacktrack(al, on_no_match);
__ bind(&success);
// Compute new value of character position after the matched part.
__ sub(current_input_offset(), r2, end_of_input_address());
} else {
DCHECK(mode_ == UC16);
int argument_count = 4;
__ PrepareCallCFunction(argument_count, r2);
// r0 - offset of start of capture
// r1 - length of capture
// Put arguments into arguments registers.
// Parameters are
// r0: Address byte_offset1 - Address captured substring's start.
// r1: Address byte_offset2 - Address of current character position.
// r2: size_t byte_length - length of capture in bytes(!)
// r3: Isolate* isolate
// Address of start of capture.
__ add(r0, r0, Operand(end_of_input_address()));
// Length of capture.
__ mov(r2, Operand(r1));
// Save length in callee-save register for use on return.
__ mov(r4, Operand(r1));
// Address of current input position.
__ add(r1, current_input_offset(), Operand(end_of_input_address()));
// Isolate.
__ mov(r3, Operand(ExternalReference::isolate_address(isolate())));
{
AllowExternalCallThatCantCauseGC scope(masm_);
ExternalReference function =
ExternalReference::re_case_insensitive_compare_uc16(isolate());
__ CallCFunction(function, argument_count);
}
// Check if function returned non-zero for success or zero for failure.
__ cmp(r0, Operand::Zero());
BranchOrBacktrack(eq, on_no_match);
// On success, increment position by length of capture.
__ add(current_input_offset(), current_input_offset(), Operand(r4));
}
__ bind(&fallthrough);
}
void RegExpMacroAssemblerARM::CheckNotBackReference(
int start_reg,
Label* on_no_match) {
Label fallthrough;
Label success;
// Find length of back-referenced capture.
__ ldr(r0, register_location(start_reg));
__ ldr(r1, register_location(start_reg + 1));
__ sub(r1, r1, r0, SetCC); // Length to check.
// Succeed on empty capture (including no capture).
__ b(eq, &fallthrough);
// Check that there are enough characters left in the input.
__ cmn(r1, Operand(current_input_offset()));
BranchOrBacktrack(gt, on_no_match);
// Compute pointers to match string and capture string
__ add(r0, r0, Operand(end_of_input_address()));
__ add(r2, end_of_input_address(), Operand(current_input_offset()));
__ add(r1, r1, Operand(r0));
Label loop;
__ bind(&loop);
if (mode_ == LATIN1) {
__ ldrb(r3, MemOperand(r0, char_size(), PostIndex));
__ ldrb(r4, MemOperand(r2, char_size(), PostIndex));
} else {
DCHECK(mode_ == UC16);
__ ldrh(r3, MemOperand(r0, char_size(), PostIndex));
__ ldrh(r4, MemOperand(r2, char_size(), PostIndex));
}
__ cmp(r3, r4);
BranchOrBacktrack(ne, on_no_match);
__ cmp(r0, r1);
__ b(lt, &loop);
// Move current character position to position after match.
__ sub(current_input_offset(), r2, end_of_input_address());
__ bind(&fallthrough);
}
void RegExpMacroAssemblerARM::CheckNotCharacter(unsigned c,
Label* on_not_equal) {
__ cmp(current_character(), Operand(c));
BranchOrBacktrack(ne, on_not_equal);
}
void RegExpMacroAssemblerARM::CheckCharacterAfterAnd(uint32_t c,
uint32_t mask,
Label* on_equal) {
if (c == 0) {
__ tst(current_character(), Operand(mask));
} else {
__ and_(r0, current_character(), Operand(mask));
__ cmp(r0, Operand(c));
}
BranchOrBacktrack(eq, on_equal);
}
void RegExpMacroAssemblerARM::CheckNotCharacterAfterAnd(unsigned c,
unsigned mask,
Label* on_not_equal) {
if (c == 0) {
__ tst(current_character(), Operand(mask));
} else {
__ and_(r0, current_character(), Operand(mask));
__ cmp(r0, Operand(c));
}
BranchOrBacktrack(ne, on_not_equal);
}
void RegExpMacroAssemblerARM::CheckNotCharacterAfterMinusAnd(
uc16 c,
uc16 minus,
uc16 mask,
Label* on_not_equal) {
DCHECK(minus < String::kMaxUtf16CodeUnit);
__ sub(r0, current_character(), Operand(minus));
__ and_(r0, r0, Operand(mask));
__ cmp(r0, Operand(c));
BranchOrBacktrack(ne, on_not_equal);
}
void RegExpMacroAssemblerARM::CheckCharacterInRange(
uc16 from,
uc16 to,
Label* on_in_range) {
__ sub(r0, current_character(), Operand(from));
__ cmp(r0, Operand(to - from));
BranchOrBacktrack(ls, on_in_range); // Unsigned lower-or-same condition.
}
void RegExpMacroAssemblerARM::CheckCharacterNotInRange(
uc16 from,
uc16 to,
Label* on_not_in_range) {
__ sub(r0, current_character(), Operand(from));
__ cmp(r0, Operand(to - from));
BranchOrBacktrack(hi, on_not_in_range); // Unsigned higher condition.
}
void RegExpMacroAssemblerARM::CheckBitInTable(
Handle<ByteArray> table,
Label* on_bit_set) {
__ mov(r0, Operand(table));
if (mode_ != LATIN1 || kTableMask != String::kMaxOneByteCharCode) {
__ and_(r1, current_character(), Operand(kTableSize - 1));
__ add(r1, r1, Operand(ByteArray::kHeaderSize - kHeapObjectTag));
} else {
__ add(r1,
current_character(),
Operand(ByteArray::kHeaderSize - kHeapObjectTag));
}
__ ldrb(r0, MemOperand(r0, r1));
__ cmp(r0, Operand::Zero());
BranchOrBacktrack(ne, on_bit_set);
}
bool RegExpMacroAssemblerARM::CheckSpecialCharacterClass(uc16 type,
Label* on_no_match) {
// Range checks (c in min..max) are generally implemented by an unsigned
// (c - min) <= (max - min) check
switch (type) {
case 's':
// Match space-characters
if (mode_ == LATIN1) {
// One byte space characters are '\t'..'\r', ' ' and \u00a0.
Label success;
__ cmp(current_character(), Operand(' '));
__ b(eq, &success);
// Check range 0x09..0x0d
__ sub(r0, current_character(), Operand('\t'));
__ cmp(r0, Operand('\r' - '\t'));
__ b(ls, &success);
// \u00a0 (NBSP).
__ cmp(r0, Operand(0x00a0 - '\t'));
BranchOrBacktrack(ne, on_no_match);
__ bind(&success);
return true;
}
return false;
case 'S':
// The emitted code for generic character classes is good enough.
return false;
case 'd':
// Match ASCII digits ('0'..'9')
__ sub(r0, current_character(), Operand('0'));
__ cmp(r0, Operand('9' - '0'));
BranchOrBacktrack(hi, on_no_match);
return true;
case 'D':
// Match non ASCII-digits
__ sub(r0, current_character(), Operand('0'));
__ cmp(r0, Operand('9' - '0'));
BranchOrBacktrack(ls, on_no_match);
return true;
case '.': {
// Match non-newlines (not 0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
__ eor(r0, current_character(), Operand(0x01));
// See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
__ sub(r0, r0, Operand(0x0b));
__ cmp(r0, Operand(0x0c - 0x0b));
BranchOrBacktrack(ls, on_no_match);
if (mode_ == UC16) {
// Compare original value to 0x2028 and 0x2029, using the already
// computed (current_char ^ 0x01 - 0x0b). I.e., check for
// 0x201d (0x2028 - 0x0b) or 0x201e.
__ sub(r0, r0, Operand(0x2028 - 0x0b));
__ cmp(r0, Operand(1));
BranchOrBacktrack(ls, on_no_match);
}
return true;
}
case 'n': {
// Match newlines (0x0a('\n'), 0x0d('\r'), 0x2028 and 0x2029)
__ eor(r0, current_character(), Operand(0x01));
// See if current character is '\n'^1 or '\r'^1, i.e., 0x0b or 0x0c
__ sub(r0, r0, Operand(0x0b));
__ cmp(r0, Operand(0x0c - 0x0b));
if (mode_ == LATIN1) {
BranchOrBacktrack(hi, on_no_match);
} else {
Label done;
__ b(ls, &done);
// Compare original value to 0x2028 and 0x2029, using the already
// computed (current_char ^ 0x01 - 0x0b). I.e., check for
// 0x201d (0x2028 - 0x0b) or 0x201e.
__ sub(r0, r0, Operand(0x2028 - 0x0b));
__ cmp(r0, Operand(1));
BranchOrBacktrack(hi, on_no_match);
__ bind(&done);
}
return true;
}
case 'w': {
if (mode_ != LATIN1) {
// Table is 256 entries, so all Latin1 characters can be tested.
__ cmp(current_character(), Operand('z'));
BranchOrBacktrack(hi, on_no_match);
}
ExternalReference map = ExternalReference::re_word_character_map();
__ mov(r0, Operand(map));
__ ldrb(r0, MemOperand(r0, current_character()));
__ cmp(r0, Operand::Zero());
BranchOrBacktrack(eq, on_no_match);
return true;
}
case 'W': {
Label done;
if (mode_ != LATIN1) {
// Table is 256 entries, so all Latin1 characters can be tested.
__ cmp(current_character(), Operand('z'));
__ b(hi, &done);
}
ExternalReference map = ExternalReference::re_word_character_map();
__ mov(r0, Operand(map));
__ ldrb(r0, MemOperand(r0, current_character()));
__ cmp(r0, Operand::Zero());
BranchOrBacktrack(ne, on_no_match);
if (mode_ != LATIN1) {
__ bind(&done);
}
return true;
}
case '*':
// Match any character.
return true;
// No custom implementation (yet): s(UC16), S(UC16).
default:
return false;
}
}
void RegExpMacroAssemblerARM::Fail() {
__ mov(r0, Operand(FAILURE));
__ jmp(&exit_label_);
}
Handle<HeapObject> RegExpMacroAssemblerARM::GetCode(Handle<String> source) {
Label return_r0;
// Finalize code - write the entry point code now we know how many
// registers we need.
// Entry code:
__ bind(&entry_label_);
// Tell the system that we have a stack frame. Because the type is MANUAL, no
// is generated.
FrameScope scope(masm_, StackFrame::MANUAL);
// Actually emit code to start a new stack frame.
// Push arguments
// Save callee-save registers.
// Start new stack frame.
// Store link register in existing stack-cell.
// Order here should correspond to order of offset constants in header file.
RegList registers_to_retain = r4.bit() | r5.bit() | r6.bit() |
r7.bit() | r8.bit() | r9.bit() | r10.bit() | fp.bit();
RegList argument_registers = r0.bit() | r1.bit() | r2.bit() | r3.bit();
__ stm(db_w, sp, argument_registers | registers_to_retain | lr.bit());
// Set frame pointer in space for it if this is not a direct call
// from generated code.
__ add(frame_pointer(), sp, Operand(4 * kPointerSize));
__ mov(r0, Operand::Zero());
__ push(r0); // Make room for success counter and initialize it to 0.
__ push(r0); // Make room for "position - 1" constant (value is irrelevant).
// Check if we have space on the stack for registers.
Label stack_limit_hit;
Label stack_ok;
ExternalReference stack_limit =
ExternalReference::address_of_stack_limit(isolate());
__ mov(r0, Operand(stack_limit));
__ ldr(r0, MemOperand(r0));
__ sub(r0, sp, r0, SetCC);
// Handle it if the stack pointer is already below the stack limit.
__ b(ls, &stack_limit_hit);
// Check if there is room for the variable number of registers above
// the stack limit.
__ cmp(r0, Operand(num_registers_ * kPointerSize));
__ b(hs, &stack_ok);
// Exit with OutOfMemory exception. There is not enough space on the stack
// for our working registers.
__ mov(r0, Operand(EXCEPTION));
__ jmp(&return_r0);
__ bind(&stack_limit_hit);
CallCheckStackGuardState(r0);
__ cmp(r0, Operand::Zero());
// If returned value is non-zero, we exit with the returned value as result.
__ b(ne, &return_r0);
__ bind(&stack_ok);
// Allocate space on stack for registers.
__ sub(sp, sp, Operand(num_registers_ * kPointerSize));
// Load string end.
__ ldr(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd));
// Load input start.
__ ldr(r0, MemOperand(frame_pointer(), kInputStart));
// Find negative length (offset of start relative to end).
__ sub(current_input_offset(), r0, end_of_input_address());
// Set r0 to address of char before start of the input string
// (effectively string position -1).
__ ldr(r1, MemOperand(frame_pointer(), kStartIndex));
__ sub(r0, current_input_offset(), Operand(char_size()));
__ sub(r0, r0, Operand(r1, LSL, (mode_ == UC16) ? 1 : 0));
// Store this value in a local variable, for use when clearing
// position registers.
__ str(r0, MemOperand(frame_pointer(), kInputStartMinusOne));
// Initialize code pointer register
__ mov(code_pointer(), Operand(masm_->CodeObject()));
Label load_char_start_regexp, start_regexp;
// Load newline if index is at start, previous character otherwise.
__ cmp(r1, Operand::Zero());
__ b(ne, &load_char_start_regexp);
__ mov(current_character(), Operand('\n'), LeaveCC, eq);
__ jmp(&start_regexp);
// Global regexp restarts matching here.
__ bind(&load_char_start_regexp);
// Load previous char as initial value of current character register.
LoadCurrentCharacterUnchecked(-1, 1);
__ bind(&start_regexp);
// Initialize on-stack registers.
if (num_saved_registers_ > 0) { // Always is, if generated from a regexp.
// Fill saved registers with initial value = start offset - 1
if (num_saved_registers_ > 8) {
// Address of register 0.
__ add(r1, frame_pointer(), Operand(kRegisterZero));
__ mov(r2, Operand(num_saved_registers_));
Label init_loop;
__ bind(&init_loop);
__ str(r0, MemOperand(r1, kPointerSize, NegPostIndex));
__ sub(r2, r2, Operand(1), SetCC);
__ b(ne, &init_loop);
} else {
for (int i = 0; i < num_saved_registers_; i++) {
__ str(r0, register_location(i));
}
}
}
// Initialize backtrack stack pointer.
__ ldr(backtrack_stackpointer(), MemOperand(frame_pointer(), kStackHighEnd));
__ jmp(&start_label_);
// Exit code:
if (success_label_.is_linked()) {
// Save captures when successful.
__ bind(&success_label_);
if (num_saved_registers_ > 0) {
// copy captures to output
__ ldr(r1, MemOperand(frame_pointer(), kInputStart));
__ ldr(r0, MemOperand(frame_pointer(), kRegisterOutput));
__ ldr(r2, MemOperand(frame_pointer(), kStartIndex));
__ sub(r1, end_of_input_address(), r1);
// r1 is length of input in bytes.
if (mode_ == UC16) {
__ mov(r1, Operand(r1, LSR, 1));
}
// r1 is length of input in characters.
__ add(r1, r1, Operand(r2));
// r1 is length of string in characters.
DCHECK_EQ(0, num_saved_registers_ % 2);
// Always an even number of capture registers. This allows us to
// unroll the loop once to add an operation between a load of a register
// and the following use of that register.
for (int i = 0; i < num_saved_registers_; i += 2) {
__ ldr(r2, register_location(i));
__ ldr(r3, register_location(i + 1));
if (i == 0 && global_with_zero_length_check()) {
// Keep capture start in r4 for the zero-length check later.
__ mov(r4, r2);
}
if (mode_ == UC16) {
__ add(r2, r1, Operand(r2, ASR, 1));
__ add(r3, r1, Operand(r3, ASR, 1));
} else {
__ add(r2, r1, Operand(r2));
__ add(r3, r1, Operand(r3));
}
__ str(r2, MemOperand(r0, kPointerSize, PostIndex));
__ str(r3, MemOperand(r0, kPointerSize, PostIndex));
}
}
if (global()) {
// Restart matching if the regular expression is flagged as global.
__ ldr(r0, MemOperand(frame_pointer(), kSuccessfulCaptures));
__ ldr(r1, MemOperand(frame_pointer(), kNumOutputRegisters));
__ ldr(r2, MemOperand(frame_pointer(), kRegisterOutput));
// Increment success counter.
__ add(r0, r0, Operand(1));
__ str(r0, MemOperand(frame_pointer(), kSuccessfulCaptures));
// Capture results have been stored, so the number of remaining global
// output registers is reduced by the number of stored captures.
__ sub(r1, r1, Operand(num_saved_registers_));
// Check whether we have enough room for another set of capture results.
__ cmp(r1, Operand(num_saved_registers_));
__ b(lt, &return_r0);
__ str(r1, MemOperand(frame_pointer(), kNumOutputRegisters));
// Advance the location for output.
__ add(r2, r2, Operand(num_saved_registers_ * kPointerSize));
__ str(r2, MemOperand(frame_pointer(), kRegisterOutput));
// Prepare r0 to initialize registers with its value in the next run.
__ ldr(r0, MemOperand(frame_pointer(), kInputStartMinusOne));
if (global_with_zero_length_check()) {
// Special case for zero-length matches.
// r4: capture start index
__ cmp(current_input_offset(), r4);
// Not a zero-length match, restart.
__ b(ne, &load_char_start_regexp);
// Offset from the end is zero if we already reached the end.
__ cmp(current_input_offset(), Operand::Zero());
__ b(eq, &exit_label_);
// Advance current position after a zero-length match.
__ add(current_input_offset(),
current_input_offset(),
Operand((mode_ == UC16) ? 2 : 1));
}
__ b(&load_char_start_regexp);
} else {
__ mov(r0, Operand(SUCCESS));
}
}
// Exit and return r0
__ bind(&exit_label_);
if (global()) {
__ ldr(r0, MemOperand(frame_pointer(), kSuccessfulCaptures));
}
__ bind(&return_r0);
// Skip sp past regexp registers and local variables..
__ mov(sp, frame_pointer());
// Restore registers r4..r11 and return (restoring lr to pc).
__ ldm(ia_w, sp, registers_to_retain | pc.bit());
// Backtrack code (branch target for conditional backtracks).
if (backtrack_label_.is_linked()) {
__ bind(&backtrack_label_);
Backtrack();
}
Label exit_with_exception;
// Preempt-code
if (check_preempt_label_.is_linked()) {
SafeCallTarget(&check_preempt_label_);
CallCheckStackGuardState(r0);
__ cmp(r0, Operand::Zero());
// If returning non-zero, we should end execution with the given
// result as return value.
__ b(ne, &return_r0);
// String might have moved: Reload end of string from frame.
__ ldr(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd));
SafeReturn();
}
// Backtrack stack overflow code.
if (stack_overflow_label_.is_linked()) {
SafeCallTarget(&stack_overflow_label_);
// Reached if the backtrack-stack limit has been hit.
Label grow_failed;
// Call GrowStack(backtrack_stackpointer(), &stack_base)
static const int num_arguments = 3;
__ PrepareCallCFunction(num_arguments, r0);
__ mov(r0, backtrack_stackpointer());
__ add(r1, frame_pointer(), Operand(kStackHighEnd));
__ mov(r2, Operand(ExternalReference::isolate_address(isolate())));
ExternalReference grow_stack =
ExternalReference::re_grow_stack(isolate());
__ CallCFunction(grow_stack, num_arguments);
// If return NULL, we have failed to grow the stack, and
// must exit with a stack-overflow exception.
__ cmp(r0, Operand::Zero());
__ b(eq, &exit_with_exception);
// Otherwise use return value as new stack pointer.
__ mov(backtrack_stackpointer(), r0);
// Restore saved registers and continue.
SafeReturn();
}
if (exit_with_exception.is_linked()) {
// If any of the code above needed to exit with an exception.
__ bind(&exit_with_exception);
// Exit with Result EXCEPTION(-1) to signal thrown exception.
__ mov(r0, Operand(EXCEPTION));
__ jmp(&return_r0);
}
CodeDesc code_desc;
masm_->GetCode(&code_desc);
Handle<Code> code = isolate()->factory()->NewCode(
code_desc, Code::ComputeFlags(Code::REGEXP), masm_->CodeObject());
PROFILE(masm_->isolate(), RegExpCodeCreateEvent(*code, *source));
return Handle<HeapObject>::cast(code);
}
void RegExpMacroAssemblerARM::GoTo(Label* to) {
BranchOrBacktrack(al, to);
}
void RegExpMacroAssemblerARM::IfRegisterGE(int reg,
int comparand,
Label* if_ge) {
__ ldr(r0, register_location(reg));
__ cmp(r0, Operand(comparand));
BranchOrBacktrack(ge, if_ge);
}
void RegExpMacroAssemblerARM::IfRegisterLT(int reg,
int comparand,
Label* if_lt) {
__ ldr(r0, register_location(reg));
__ cmp(r0, Operand(comparand));
BranchOrBacktrack(lt, if_lt);
}
void RegExpMacroAssemblerARM::IfRegisterEqPos(int reg,
Label* if_eq) {
__ ldr(r0, register_location(reg));
__ cmp(r0, Operand(current_input_offset()));
BranchOrBacktrack(eq, if_eq);
}
RegExpMacroAssembler::IrregexpImplementation
RegExpMacroAssemblerARM::Implementation() {
return kARMImplementation;
}
void RegExpMacroAssemblerARM::LoadCurrentCharacter(int cp_offset,
Label* on_end_of_input,
bool check_bounds,
int characters) {
DCHECK(cp_offset >= -1); // ^ and \b can look behind one character.
DCHECK(cp_offset < (1<<30)); // Be sane! (And ensure negation works)
if (check_bounds) {
CheckPosition(cp_offset + characters - 1, on_end_of_input);
}
LoadCurrentCharacterUnchecked(cp_offset, characters);
}
void RegExpMacroAssemblerARM::PopCurrentPosition() {
Pop(current_input_offset());
}
void RegExpMacroAssemblerARM::PopRegister(int register_index) {
Pop(r0);
__ str(r0, register_location(register_index));
}
void RegExpMacroAssemblerARM::PushBacktrack(Label* label) {
__ mov_label_offset(r0, label);
Push(r0);
CheckStackLimit();
}
void RegExpMacroAssemblerARM::PushCurrentPosition() {
Push(current_input_offset());
}
void RegExpMacroAssemblerARM::PushRegister(int register_index,
StackCheckFlag check_stack_limit) {
__ ldr(r0, register_location(register_index));
Push(r0);
if (check_stack_limit) CheckStackLimit();
}
void RegExpMacroAssemblerARM::ReadCurrentPositionFromRegister(int reg) {
__ ldr(current_input_offset(), register_location(reg));
}
void RegExpMacroAssemblerARM::ReadStackPointerFromRegister(int reg) {
__ ldr(backtrack_stackpointer(), register_location(reg));
__ ldr(r0, MemOperand(frame_pointer(), kStackHighEnd));
__ add(backtrack_stackpointer(), backtrack_stackpointer(), Operand(r0));
}
void RegExpMacroAssemblerARM::SetCurrentPositionFromEnd(int by) {
Label after_position;
__ cmp(current_input_offset(), Operand(-by * char_size()));
__ b(ge, &after_position);
__ mov(current_input_offset(), Operand(-by * char_size()));
// On RegExp code entry (where this operation is used), the character before
// the current position is expected to be already loaded.
// We have advanced the position, so it's safe to read backwards.
LoadCurrentCharacterUnchecked(-1, 1);
__ bind(&after_position);
}
void RegExpMacroAssemblerARM::SetRegister(int register_index, int to) {
DCHECK(register_index >= num_saved_registers_); // Reserved for positions!
__ mov(r0, Operand(to));
__ str(r0, register_location(register_index));
}
bool RegExpMacroAssemblerARM::Succeed() {
__ jmp(&success_label_);
return global();
}
void RegExpMacroAssemblerARM::WriteCurrentPositionToRegister(int reg,
int cp_offset) {
if (cp_offset == 0) {
__ str(current_input_offset(), register_location(reg));
} else {
__ add(r0, current_input_offset(), Operand(cp_offset * char_size()));
__ str(r0, register_location(reg));
}
}
void RegExpMacroAssemblerARM::ClearRegisters(int reg_from, int reg_to) {
DCHECK(reg_from <= reg_to);
__ ldr(r0, MemOperand(frame_pointer(), kInputStartMinusOne));
for (int reg = reg_from; reg <= reg_to; reg++) {
__ str(r0, register_location(reg));
}
}
void RegExpMacroAssemblerARM::WriteStackPointerToRegister(int reg) {
__ ldr(r1, MemOperand(frame_pointer(), kStackHighEnd));
__ sub(r0, backtrack_stackpointer(), r1);
__ str(r0, register_location(reg));
}
// Private methods:
void RegExpMacroAssemblerARM::CallCheckStackGuardState(Register scratch) {
__ PrepareCallCFunction(3, scratch);
// RegExp code frame pointer.
__ mov(r2, frame_pointer());
// Code* of self.
__ mov(r1, Operand(masm_->CodeObject()));
// We need to make room for the return address on the stack.
int stack_alignment = base::OS::ActivationFrameAlignment();
DCHECK(IsAligned(stack_alignment, kPointerSize));
__ sub(sp, sp, Operand(stack_alignment));
// r0 will point to the return address, placed by DirectCEntry.
__ mov(r0, sp);
ExternalReference stack_guard_check =
ExternalReference::re_check_stack_guard_state(isolate());
__ mov(ip, Operand(stack_guard_check));
DirectCEntryStub stub(isolate());
stub.GenerateCall(masm_, ip);
// Drop the return address from the stack.
__ add(sp, sp, Operand(stack_alignment));
DCHECK(stack_alignment != 0);
__ ldr(sp, MemOperand(sp, 0));
__ mov(code_pointer(), Operand(masm_->CodeObject()));
}
// Helper function for reading a value out of a stack frame.
template <typename T>
static T& frame_entry(Address re_frame, int frame_offset) {
return reinterpret_cast<T&>(Memory::int32_at(re_frame + frame_offset));
}
int RegExpMacroAssemblerARM::CheckStackGuardState(Address* return_address,
Code* re_code,
Address re_frame) {
Isolate* isolate = frame_entry<Isolate*>(re_frame, kIsolate);
StackLimitCheck check(isolate);
if (check.JsHasOverflowed()) {
isolate->StackOverflow();
return EXCEPTION;
}
// If not real stack overflow the stack guard was used to interrupt
// execution for another purpose.
// If this is a direct call from JavaScript retry the RegExp forcing the call
// through the runtime system. Currently the direct call cannot handle a GC.
if (frame_entry<int>(re_frame, kDirectCall) == 1) {
return RETRY;
}
// Prepare for possible GC.
HandleScope handles(isolate);
Handle<Code> code_handle(re_code);
Handle<String> subject(frame_entry<String*>(re_frame, kInputString));
// Current string.
bool is_one_byte = subject->IsOneByteRepresentationUnderneath();
DCHECK(re_code->instruction_start() <= *return_address);
DCHECK(*return_address <=
re_code->instruction_start() + re_code->instruction_size());
Object* result = isolate->stack_guard()->HandleInterrupts();
if (*code_handle != re_code) { // Return address no longer valid
int delta = code_handle->address() - re_code->address();
// Overwrite the return address on the stack.
*return_address += delta;
}
if (result->IsException()) {
return EXCEPTION;
}
Handle<String> subject_tmp = subject;
int slice_offset = 0;
// Extract the underlying string and the slice offset.
if (StringShape(*subject_tmp).IsCons()) {
subject_tmp = Handle<String>(ConsString::cast(*subject_tmp)->first());
} else if (StringShape(*subject_tmp).IsSliced()) {
SlicedString* slice = SlicedString::cast(*subject_tmp);
subject_tmp = Handle<String>(slice->parent());
slice_offset = slice->offset();
}
// String might have changed.
if (subject_tmp->IsOneByteRepresentation() != is_one_byte) {
// If we changed between an Latin1 and an UC16 string, the specialized
// code cannot be used, and we need to restart regexp matching from
// scratch (including, potentially, compiling a new version of the code).
return RETRY;
}
// Otherwise, the content of the string might have moved. It must still
// be a sequential or external string with the same content.
// Update the start and end pointers in the stack frame to the current
// location (whether it has actually moved or not).
DCHECK(StringShape(*subject_tmp).IsSequential() ||
StringShape(*subject_tmp).IsExternal());
// The original start address of the characters to match.
const byte* start_address = frame_entry<const byte*>(re_frame, kInputStart);
// Find the current start address of the same character at the current string
// position.
int start_index = frame_entry<int>(re_frame, kStartIndex);
const byte* new_address = StringCharacterPosition(*subject_tmp,
start_index + slice_offset);
if (start_address != new_address) {
// If there is a difference, update the object pointer and start and end
// addresses in the RegExp stack frame to match the new value.
const byte* end_address = frame_entry<const byte* >(re_frame, kInputEnd);
int byte_length = static_cast<int>(end_address - start_address);
frame_entry<const String*>(re_frame, kInputString) = *subject;
frame_entry<const byte*>(re_frame, kInputStart) = new_address;
frame_entry<const byte*>(re_frame, kInputEnd) = new_address + byte_length;
} else if (frame_entry<const String*>(re_frame, kInputString) != *subject) {
// Subject string might have been a ConsString that underwent
// short-circuiting during GC. That will not change start_address but
// will change pointer inside the subject handle.
frame_entry<const String*>(re_frame, kInputString) = *subject;
}
return 0;
}
MemOperand RegExpMacroAssemblerARM::register_location(int register_index) {
DCHECK(register_index < (1<<30));
if (num_registers_ <= register_index) {
num_registers_ = register_index + 1;
}
return MemOperand(frame_pointer(),
kRegisterZero - register_index * kPointerSize);
}
void RegExpMacroAssemblerARM::CheckPosition(int cp_offset,
Label* on_outside_input) {
__ cmp(current_input_offset(), Operand(-cp_offset * char_size()));
BranchOrBacktrack(ge, on_outside_input);
}
void RegExpMacroAssemblerARM::BranchOrBacktrack(Condition condition,
Label* to) {
if (condition == al) { // Unconditional.
if (to == NULL) {
Backtrack();
return;
}
__ jmp(to);
return;
}
if (to == NULL) {
__ b(condition, &backtrack_label_);
return;
}
__ b(condition, to);
}
void RegExpMacroAssemblerARM::SafeCall(Label* to, Condition cond) {
__ bl(to, cond);
}
void RegExpMacroAssemblerARM::SafeReturn() {
__ pop(lr);
__ add(pc, lr, Operand(masm_->CodeObject()));
}
void RegExpMacroAssemblerARM::SafeCallTarget(Label* name) {
__ bind(name);
__ sub(lr, lr, Operand(masm_->CodeObject()));
__ push(lr);
}
void RegExpMacroAssemblerARM::Push(Register source) {
DCHECK(!source.is(backtrack_stackpointer()));
__ str(source,
MemOperand(backtrack_stackpointer(), kPointerSize, NegPreIndex));
}
void RegExpMacroAssemblerARM::Pop(Register target) {
DCHECK(!target.is(backtrack_stackpointer()));
__ ldr(target,
MemOperand(backtrack_stackpointer(), kPointerSize, PostIndex));
}
void RegExpMacroAssemblerARM::CheckPreemption() {
// Check for preemption.
ExternalReference stack_limit =
ExternalReference::address_of_stack_limit(isolate());
__ mov(r0, Operand(stack_limit));
__ ldr(r0, MemOperand(r0));
__ cmp(sp, r0);
SafeCall(&check_preempt_label_, ls);
}
void RegExpMacroAssemblerARM::CheckStackLimit() {
ExternalReference stack_limit =
ExternalReference::address_of_regexp_stack_limit(isolate());
__ mov(r0, Operand(stack_limit));
__ ldr(r0, MemOperand(r0));
__ cmp(backtrack_stackpointer(), Operand(r0));
SafeCall(&stack_overflow_label_, ls);
}
bool RegExpMacroAssemblerARM::CanReadUnaligned() {
return CpuFeatures::IsSupported(UNALIGNED_ACCESSES) && !slow_safe();
}
void RegExpMacroAssemblerARM::LoadCurrentCharacterUnchecked(int cp_offset,
int characters) {
Register offset = current_input_offset();
if (cp_offset != 0) {
// r4 is not being used to store the capture start index at this point.
__ add(r4, current_input_offset(), Operand(cp_offset * char_size()));
offset = r4;
}
// The ldr, str, ldrh, strh instructions can do unaligned accesses, if the CPU
// and the operating system running on the target allow it.
// If unaligned load/stores are not supported then this function must only
// be used to load a single character at a time.
if (!CanReadUnaligned()) {
DCHECK(characters == 1);
}
if (mode_ == LATIN1) {
if (characters == 4) {
__ ldr(current_character(), MemOperand(end_of_input_address(), offset));
} else if (characters == 2) {
__ ldrh(current_character(), MemOperand(end_of_input_address(), offset));
} else {
DCHECK(characters == 1);
__ ldrb(current_character(), MemOperand(end_of_input_address(), offset));
}
} else {
DCHECK(mode_ == UC16);
if (characters == 2) {
__ ldr(current_character(), MemOperand(end_of_input_address(), offset));
} else {
DCHECK(characters == 1);
__ ldrh(current_character(), MemOperand(end_of_input_address(), offset));
}
}
}
#undef __
#endif // V8_INTERPRETED_REGEXP
}} // namespace v8::internal
#endif // V8_TARGET_ARCH_ARM