src/cc/usdt/usdt_args.cc - platform/external/bcc - Git at Google

 /*
  * Copyright (c) 2016 GitHub, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 #include <unordered_map>
 #include <regex>

 #include "syms.h"
 #include "usdt.h"
 #include "vendor/tinyformat.hpp"

 #include "bcc_elf.h"
 #include "bcc_syms.h"

 namespace USDT {

 Argument::Argument() {}
 Argument::~Argument() {}

 std::string Argument::ctype() const {
   const int s = arg_size() * 8;
   return (s < 0) ? tfm::format("int%d_t", -s) : tfm::format("uint%d_t", s);
 }

 bool Argument::get_global_address(uint64_t *address, const std::string &binpath,
                                   const optional<int> &pid) const {
   if (pid) {
     static struct bcc_symbol_option default_option = {
       .use_debug_file = 1,
       .check_debug_file_crc = 1,
       .use_symbol_type = BCC_SYM_ALL_TYPES
     };
     return ProcSyms(*pid, &default_option)
         .resolve_name(binpath.c_str(), deref_ident_->c_str(), address);
   }

   if (!bcc_elf_is_shared_obj(binpath.c_str())) {
     struct bcc_symbol sym;
     if (bcc_resolve_symname(binpath.c_str(), deref_ident_->c_str(), 0x0, -1, nullptr, &sym) == 0) {
       *address = sym.offset;
       if (sym.module)
         ::free(const_cast<char*>(sym.module));
       return true;
     }
   }

   return false;
 }

 bool Argument::assign_to_local(std::ostream &stream,
                                const std::string &local_name,
                                const std::string &binpath,
                                const optional<int> &pid) const {
   if (constant_) {
     tfm::format(stream, "%s = %d;", local_name, *constant_);
     return true;
   }

   if (!deref_offset_) {
     tfm::format(stream, "%s = ctx->%s;", local_name, *base_register_name_);
     // Put a compiler barrier to prevent optimization
     // like llvm SimplifyCFG SinkThenElseCodeToEnd
     // Volatile marking is not sufficient to prevent such optimization.
     tfm::format(stream, " %s", COMPILER_BARRIER);
     return true;
   }

   if (deref_offset_ && !deref_ident_) {
     tfm::format(stream, "{ u64 __addr = ctx->%s + %d",
                 *base_register_name_, *deref_offset_);
     if (index_register_name_) {
       int scale = scale_.value_or(1);
       tfm::format(stream, " + (ctx->%s * %d);", *index_register_name_, scale);
     } else {
       tfm::format(stream, ";");
     }
     // Theoretically, llvm SimplifyCFG SinkThenElseCodeToEnd may still
     // sink bpf_probe_read call, so put a barrier here to prevent sinking
     // of ctx->#fields.
     tfm::format(stream, " %s ", COMPILER_BARRIER);
     tfm::format(stream,
                 "%s __res = 0x0; "
                 "bpf_probe_read(&__res, sizeof(__res), (void *)__addr); "
                 "%s = __res; }",
                 ctype(), local_name);
     return true;
   }

   if (deref_offset_ && deref_ident_ && *base_register_name_ == "ip") {
     uint64_t global_address;
     if (!get_global_address(&global_address, binpath, pid))
       return false;

     tfm::format(stream,
                 "{ u64 __addr = 0x%xull + %d; %s __res = 0x0; "
                 "bpf_probe_read(&__res, sizeof(__res), (void *)__addr); "
                 "%s = __res; }",
                 global_address, *deref_offset_, ctype(), local_name);
     return true;
   }

   return false;
 }

 void ArgumentParser::print_error(ssize_t pos) {
   fprintf(stderr, "Parse error:\n    %s\n", arg_);
   for (ssize_t i = 0; i < pos + 4; ++i) fputc('-', stderr);
   fputc('^', stderr);
   fputc('\n', stderr);
 }

 void ArgumentParser::skip_whitespace_from(size_t pos) {
     while (isspace(arg_[pos])) pos++;
     cur_pos_ = pos;
 }

 void ArgumentParser::skip_until_whitespace_from(size_t pos) {
     while (arg_[pos] != '\0' && !isspace(arg_[pos]))
         pos++;
     cur_pos_ = pos;
 }

 bool ArgumentParser_aarch64::parse_register(ssize_t pos, ssize_t &new_pos,
                                             optional<int> *reg_num) {
   new_pos = parse_number(pos, reg_num);
   if (new_pos == pos || *reg_num < 0 || *reg_num > 31)
     return error_return(pos, pos);
   return true;
 }

 bool ArgumentParser_aarch64::parse_size(ssize_t pos, ssize_t &new_pos,
                                         optional<int> *arg_size) {
   int abs_arg_size;

   new_pos = parse_number(pos, arg_size);
   if (new_pos == pos)
     return error_return(pos, pos);

   abs_arg_size = abs(arg_size->value());
   if (abs_arg_size != 1 && abs_arg_size != 2 && abs_arg_size != 4 &&
       abs_arg_size != 8)
     return error_return(pos, pos);
   return true;
 }

 bool ArgumentParser_aarch64::parse_mem(ssize_t pos, ssize_t &new_pos,
                                        optional<int> *reg_num,
                                        optional<int> *offset) {
   if (arg_[pos] != 'x')
     return error_return(pos, pos);
   if (parse_register(pos + 1, new_pos, reg_num) == false)
     return false;

   if (arg_[new_pos] == ',') {
     pos = new_pos + 1;
     new_pos = parse_number(pos, offset);
     if (new_pos == pos)
       return error_return(pos, pos);
   }
   if (arg_[new_pos] != ']')
     return error_return(new_pos, new_pos);
   new_pos++;
   return true;
 }

 bool ArgumentParser_aarch64::parse(Argument *dest) {
   if (done())
     return false;

   // Support the following argument patterns:
   //   [-]<size>@<value>, [-]<size>@<reg>, [-]<size>@[<reg>], or
   //   [-]<size>@[<reg>,<offset>]
   ssize_t cur_pos = cur_pos_, new_pos;
   optional<int> arg_size;

   // Parse [-]<size>
   if (parse_size(cur_pos, new_pos, &arg_size) == false)
     return false;
   dest->arg_size_ = arg_size;

   // Make sure '@' present
   if (arg_[new_pos] != '@')
     return error_return(new_pos, new_pos);
   cur_pos = new_pos + 1;

   if (arg_[cur_pos] == 'x') {
     // Parse ...@<reg>
     optional<int> reg_num;
     if (parse_register(cur_pos + 1, new_pos, &reg_num) == false)
       return false;
     cur_pos_ = new_pos;
     dest->base_register_name_ = "regs[" + std::to_string(reg_num.value()) + "]";
   } else if (arg_[cur_pos] == '[') {
     // Parse ...@[<reg>] and ...@[<reg,<offset>]
     optional<int> reg_num, offset = 0;
     if (parse_mem(cur_pos + 1, new_pos, &reg_num, &offset) == false)
       return false;
     cur_pos_ = new_pos;
     dest->base_register_name_ = "regs[" + std::to_string(reg_num.value()) + "]";
     dest->deref_offset_ = offset;
   } else {
     // Parse ...@<value>
     optional<int> val;
     new_pos = parse_number(cur_pos, &val);
     if (cur_pos == new_pos)
       return error_return(cur_pos, cur_pos);
     cur_pos_ = new_pos;
     dest->constant_ = val;
   }

   skip_whitespace_from(cur_pos_);
   return true;
 }

 bool ArgumentParser_powerpc64::parse(Argument *dest) {
   if (done())
     return false;

   bool matched;
   std::smatch matches;
   std::string arg_str(&arg_[cur_pos_]);
   std::regex arg_n_regex("^(\\-?[1248])\\@");
   // Operands with constants of form iNUM or i-NUM
   std::regex arg_op_regex_const("^i(\\-?[0-9]+)( +|$)");
   // Operands with register only of form REG or %rREG
   std::regex arg_op_regex_reg("^(?:%r)?([1-2]?[0-9]|3[0-1])( +|$)");
   // Operands with a base register and an offset of form
   // NUM(REG) or -NUM(REG) or NUM(%rREG) or -NUM(%rREG)
   std::regex arg_op_regex_breg_off(
         "^(\\-?[0-9]+)\\((?:%r)?([1-2]?[0-9]|3[0-1])\\)( +|$)");
   // Operands with a base register and an index register
   // of form REG,REG or %rREG,%rREG
   std::regex arg_op_regex_breg_ireg(
         "^(?:%r)?([1-2]?[0-9]|3[0-1])\\,(?:%r)?([1-2]?[0-9]|3[0-1])( +|$)");

   matched = std::regex_search(arg_str, matches, arg_n_regex);
   if (matched) {
     dest->arg_size_ = stoi(matches.str(1));
     cur_pos_ += matches.length(0);
     arg_str = &arg_[cur_pos_];

     if (std::regex_search(arg_str, matches, arg_op_regex_const)) {
       dest->constant_ = stoi(matches.str(1));
     } else if (std::regex_search(arg_str, matches, arg_op_regex_reg)) {
       dest->base_register_name_ = "gpr[" + matches.str(1) + "]";
     } else if (std::regex_search(arg_str, matches, arg_op_regex_breg_off)) {
       dest->deref_offset_ = stoi(matches.str(1));
       dest->base_register_name_ = "gpr[" + matches.str(2) + "]";
     } else if (std::regex_search(arg_str, matches, arg_op_regex_breg_ireg)) {
       dest->deref_offset_ = 0; // In powerpc64, such operands contain a base
                                // register and an index register which are
                                // part of an indexed load/store operation.
                                // Even if no offset value is present, this
                                // is required by Argument::assign_to_local()
                                // in order to generate code for reading the
                                // argument. So, this is set to zero.
       dest->base_register_name_ = "gpr[" + matches.str(1) + "]";
       dest->index_register_name_ = "gpr[" + matches.str(2) + "]";
       dest->scale_ = abs(*dest->arg_size_);
     } else {
       matched = false;
     }
   }

   if (!matched) {
     print_error(cur_pos_);
     skip_until_whitespace_from(cur_pos_);
     skip_whitespace_from(cur_pos_);
     return false;
   }

   cur_pos_ += matches.length(0);
   skip_whitespace_from(cur_pos_);
   return true;
 }

 ssize_t ArgumentParser_x64::parse_identifier(ssize_t pos,
                                              optional<std::string> *result) {
   if (isalpha(arg_[pos]) || arg_[pos] == '_') {
     ssize_t start = pos++;
     while (isalnum(arg_[pos]) || arg_[pos] == '_') pos++;
     if (pos - start)
       result->emplace(arg_ + start, pos - start);
   }
   return pos;
 }

 ssize_t ArgumentParser_x64::parse_register(ssize_t pos, std::string &name,
                                            int &size) {
   ssize_t start = ++pos;
   if (arg_[start - 1] != '%')
     return -start;

   while (isalnum(arg_[pos])) pos++;

   std::string regname(arg_ + start, pos - start);
   if (!normalize_register(&regname, &size))
     return -start;

   name = regname;
   return pos;
 }

 ssize_t ArgumentParser_x64::parse_base_register(ssize_t pos, Argument *dest) {
   int size;
   std::string name;
   ssize_t res = parse_register(pos, name, size);
   if (res < 0)
       return res;

   dest->base_register_name_ = name;
   if (!dest->arg_size_)
     dest->arg_size_ = size;

   return res;
 }

 ssize_t ArgumentParser_x64::parse_index_register(ssize_t pos, Argument *dest) {
   int size;
   std::string name;
   ssize_t res = parse_register(pos, name, size);
   if (res < 0)
       return res;

   dest->index_register_name_ = name;

   return res;
 }

 ssize_t ArgumentParser_x64::parse_scale(ssize_t pos, Argument *dest) {
   return parse_number(pos, &dest->scale_);
 }

 ssize_t ArgumentParser_x64::parse_expr(ssize_t pos, Argument *dest) {
   if (arg_[pos] == '$')
     return parse_number(pos + 1, &dest->constant_);

   if (arg_[pos] == '%')
     return parse_base_register(pos, dest);

   if (isdigit(arg_[pos]) || arg_[pos] == '-') {
     pos = parse_number(pos, &dest->deref_offset_);
     if (arg_[pos] == '+') {
       pos = parse_identifier(pos + 1, &dest->deref_ident_);
       if (!dest->deref_ident_)
         return -pos;
     }
   } else {
     dest->deref_offset_ = 0;
     pos = parse_identifier(pos, &dest->deref_ident_);
     if (arg_[pos] == '+' || arg_[pos] == '-') {
       pos = parse_number(pos, &dest->deref_offset_);
     }
   }

   if (arg_[pos] != '(')
     return -pos;

   pos = parse_base_register(pos + 1, dest);
   if (pos < 0)
     return pos;

   if (arg_[pos] == ',') {
     pos = parse_index_register(pos + 1, dest);
     if (pos < 0)
       return pos;

     if (arg_[pos] == ',') {
       pos = parse_scale(pos + 1, dest);
       if (pos < 0)
         return pos;
     }
   }

   return (arg_[pos] == ')') ? pos + 1 : -pos;
 }

 ssize_t ArgumentParser_x64::parse_1(ssize_t pos, Argument *dest) {
   if (isdigit(arg_[pos]) || arg_[pos] == '-') {
     optional<int> asize;
     ssize_t m = parse_number(pos, &asize);
     if (arg_[m] == '@' && asize) {
       dest->arg_size_ = asize;
       return parse_expr(m + 1, dest);
     }
   }
   return parse_expr(pos, dest);
 }

 bool ArgumentParser_x64::parse(Argument *dest) {
   if (done())
     return false;

   ssize_t res = parse_1(cur_pos_, dest);
   if (res < 0)
     return error_return(-res, -res + 1);
   if (!isspace(arg_[res]) && arg_[res] != '\0')
     return error_return(res, res);
   skip_whitespace_from(res);
   return true;
 }

 const std::unordered_map<std::string, ArgumentParser_x64::RegInfo>
     ArgumentParser_x64::registers_ = {
         {"rax", {REG_A, 8}},   {"eax", {REG_A, 4}},
         {"ax", {REG_A, 2}},    {"al", {REG_A, 1}},

         {"rbx", {REG_B, 8}},   {"ebx", {REG_B, 4}},
         {"bx", {REG_B, 2}},    {"bl", {REG_B, 1}},

         {"rcx", {REG_C, 8}},   {"ecx", {REG_C, 4}},
         {"cx", {REG_C, 2}},    {"cl", {REG_C, 1}},

         {"rdx", {REG_D, 8}},   {"edx", {REG_D, 4}},
         {"dx", {REG_D, 2}},    {"dl", {REG_D, 1}},

         {"rsi", {REG_SI, 8}},  {"esi", {REG_SI, 4}},
         {"si", {REG_SI, 2}},   {"sil", {REG_SI, 1}},

         {"rdi", {REG_DI, 8}},  {"edi", {REG_DI, 4}},
         {"di", {REG_DI, 2}},   {"dil", {REG_DI, 1}},

         {"rbp", {REG_BP, 8}},  {"ebp", {REG_BP, 4}},
         {"bp", {REG_BP, 2}},   {"bpl", {REG_BP, 1}},

         {"rsp", {REG_SP, 8}},  {"esp", {REG_SP, 4}},
         {"sp", {REG_SP, 2}},   {"spl", {REG_SP, 1}},

         {"r8", {REG_8, 8}},    {"r8d", {REG_8, 4}},
         {"r8w", {REG_8, 2}},   {"r8b", {REG_8, 1}},

         {"r9", {REG_9, 8}},    {"r9d", {REG_9, 4}},
         {"r9w", {REG_9, 2}},   {"r9b", {REG_9, 1}},

         {"r10", {REG_10, 8}},  {"r10d", {REG_10, 4}},
         {"r10w", {REG_10, 2}}, {"r10b", {REG_10, 1}},

         {"r11", {REG_11, 8}},  {"r11d", {REG_11, 4}},
         {"r11w", {REG_11, 2}}, {"r11b", {REG_11, 1}},

         {"r12", {REG_12, 8}},  {"r12d", {REG_12, 4}},
         {"r12w", {REG_12, 2}}, {"r12b", {REG_12, 1}},

         {"r13", {REG_13, 8}},  {"r13d", {REG_13, 4}},
         {"r13w", {REG_13, 2}}, {"r13b", {REG_13, 1}},

         {"r14", {REG_14, 8}},  {"r14d", {REG_14, 4}},
         {"r14w", {REG_14, 2}}, {"r14b", {REG_14, 1}},

         {"r15", {REG_15, 8}},  {"r15d", {REG_15, 4}},
         {"r15w", {REG_15, 2}}, {"r15b", {REG_15, 1}},

         {"rip", {REG_RIP, 8}},
 };

 void ArgumentParser_x64::reg_to_name(std::string *norm, Register reg) {
   switch (reg) {
   case REG_A:
     *norm = "ax";
     break;
   case REG_B:
     *norm = "bx";
     break;
   case REG_C:
     *norm = "cx";
     break;
   case REG_D:
     *norm = "dx";
     break;

   case REG_SI:
     *norm = "si";
     break;
   case REG_DI:
     *norm = "di";
     break;
   case REG_BP:
     *norm = "bp";
     break;
   case REG_SP:
     *norm = "sp";
     break;

   case REG_8:
     *norm = "r8";
     break;
   case REG_9:
     *norm = "r9";
     break;
   case REG_10:
     *norm = "r10";
     break;
   case REG_11:
     *norm = "r11";
     break;
   case REG_12:
     *norm = "r12";
     break;
   case REG_13:
     *norm = "r13";
     break;
   case REG_14:
     *norm = "r14";
     break;
   case REG_15:
     *norm = "r15";
     break;

   case REG_RIP:
     *norm = "ip";
     break;
   }
 }

 bool ArgumentParser_x64::normalize_register(std::string *reg, int *reg_size) {
   auto it = registers_.find(*reg);
   if (it == registers_.end())
     return false;

   *reg_size = it->second.size;
   reg_to_name(reg, it->second.reg);
   return true;
 }
 }
	/*
	* Copyright (c) 2016 GitHub, Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	#include <unordered_map>
	#include <regex>

	#include "syms.h"
	#include "usdt.h"
	#include "vendor/tinyformat.hpp"

	#include "bcc_elf.h"
	#include "bcc_syms.h"

	namespace USDT {

	Argument::Argument() {}
	Argument::~Argument() {}

	std::string Argument::ctype() const {
	const int s = arg_size() * 8;
	return (s < 0) ? tfm::format("int%d_t", -s) : tfm::format("uint%d_t", s);
	}

	bool Argument::get_global_address(uint64_t *address, const std::string &binpath,
	const optional<int> &pid) const {
	if (pid) {
	static struct bcc_symbol_option default_option = {
	.use_debug_file = 1,
	.check_debug_file_crc = 1,
	.use_symbol_type = BCC_SYM_ALL_TYPES
	};
	return ProcSyms(*pid, &default_option)
	.resolve_name(binpath.c_str(), deref_ident_->c_str(), address);
	}

	if (!bcc_elf_is_shared_obj(binpath.c_str())) {
	struct bcc_symbol sym;
	if (bcc_resolve_symname(binpath.c_str(), deref_ident_->c_str(), 0x0, -1, nullptr, &sym) == 0) {
	*address = sym.offset;
	if (sym.module)
	::free(const_cast<char*>(sym.module));
	return true;
	}
	}

	return false;
	}

	bool Argument::assign_to_local(std::ostream &stream,
	const std::string &local_name,
	const std::string &binpath,
	const optional<int> &pid) const {
	if (constant_) {
	tfm::format(stream, "%s = %d;", local_name, *constant_);
	return true;
	}

	if (!deref_offset_) {
	tfm::format(stream, "%s = ctx->%s;", local_name, *base_register_name_);
	// Put a compiler barrier to prevent optimization
	// like llvm SimplifyCFG SinkThenElseCodeToEnd
	// Volatile marking is not sufficient to prevent such optimization.
	tfm::format(stream, " %s", COMPILER_BARRIER);
	return true;
	}

	if (deref_offset_ && !deref_ident_) {
	tfm::format(stream, "{ u64 __addr = ctx->%s + %d",
	base_register_name_, deref_offset_);
	if (index_register_name_) {
	int scale = scale_.value_or(1);
	tfm::format(stream, " + (ctx->%s * %d);", *index_register_name_, scale);
	} else {
	tfm::format(stream, ";");
	}
	// Theoretically, llvm SimplifyCFG SinkThenElseCodeToEnd may still
	// sink bpf_probe_read call, so put a barrier here to prevent sinking
	// of ctx->#fields.
	tfm::format(stream, " %s ", COMPILER_BARRIER);
	tfm::format(stream,
	"%s __res = 0x0; "
	"bpf_probe_read(&__res, sizeof(__res), (void *)__addr); "
	"%s = __res; }",
	ctype(), local_name);
	return true;
	}

	if (deref_offset_ && deref_ident_ && *base_register_name_ == "ip") {
	uint64_t global_address;
	if (!get_global_address(&global_address, binpath, pid))
	return false;

	tfm::format(stream,
	"{ u64 __addr = 0x%xull + %d; %s __res = 0x0; "
	"bpf_probe_read(&__res, sizeof(__res), (void *)__addr); "
	"%s = __res; }",
	global_address, *deref_offset_, ctype(), local_name);
	return true;
	}

	return false;
	}

	void ArgumentParser::print_error(ssize_t pos) {
	fprintf(stderr, "Parse error:\n %s\n", arg_);
	for (ssize_t i = 0; i < pos + 4; ++i) fputc('-', stderr);
	fputc('^', stderr);
	fputc('\n', stderr);
	}

	void ArgumentParser::skip_whitespace_from(size_t pos) {
	while (isspace(arg_[pos])) pos++;
	cur_pos_ = pos;
	}

	void ArgumentParser::skip_until_whitespace_from(size_t pos) {
	while (arg_[pos] != '\0' && !isspace(arg_[pos]))
	pos++;
	cur_pos_ = pos;
	}

	bool ArgumentParser_aarch64::parse_register(ssize_t pos, ssize_t &new_pos,
	optional<int> *reg_num) {
	new_pos = parse_number(pos, reg_num);
	if (new_pos == pos \|\| reg_num < 0 \|\| reg_num > 31)
	return error_return(pos, pos);
	return true;
	}

	bool ArgumentParser_aarch64::parse_size(ssize_t pos, ssize_t &new_pos,
	optional<int> *arg_size) {
	int abs_arg_size;

	new_pos = parse_number(pos, arg_size);
	if (new_pos == pos)
	return error_return(pos, pos);

	abs_arg_size = abs(arg_size->value());
	if (abs_arg_size != 1 && abs_arg_size != 2 && abs_arg_size != 4 &&
	abs_arg_size != 8)
	return error_return(pos, pos);
	return true;
	}

	bool ArgumentParser_aarch64::parse_mem(ssize_t pos, ssize_t &new_pos,
	optional<int> *reg_num,
	optional<int> *offset) {
	if (arg_[pos] != 'x')
	return error_return(pos, pos);
	if (parse_register(pos + 1, new_pos, reg_num) == false)
	return false;

	if (arg_[new_pos] == ',') {
	pos = new_pos + 1;
	new_pos = parse_number(pos, offset);
	if (new_pos == pos)
	return error_return(pos, pos);
	}
	if (arg_[new_pos] != ']')
	return error_return(new_pos, new_pos);
	new_pos++;
	return true;
	}

	bool ArgumentParser_aarch64::parse(Argument *dest) {
	if (done())
	return false;

	// Support the following argument patterns:
	// [-]<size>@<value>, [-]<size>@<reg>, [-]<size>@[<reg>], or
	// [-]<size>@[<reg>,<offset>]
	ssize_t cur_pos = cur_pos_, new_pos;
	optional<int> arg_size;

	// Parse [-]<size>
	if (parse_size(cur_pos, new_pos, &arg_size) == false)
	return false;
	dest->arg_size_ = arg_size;

	// Make sure '@' present
	if (arg_[new_pos] != '@')
	return error_return(new_pos, new_pos);
	cur_pos = new_pos + 1;

	if (arg_[cur_pos] == 'x') {
	// Parse ...@<reg>
	optional<int> reg_num;
	if (parse_register(cur_pos + 1, new_pos, &reg_num) == false)
	return false;
	cur_pos_ = new_pos;
	dest->base_register_name_ = "regs[" + std::to_string(reg_num.value()) + "]";
	} else if (arg_[cur_pos] == '[') {
	// Parse ...@[<reg>] and ...@[<reg,<offset>]
	optional<int> reg_num, offset = 0;
	if (parse_mem(cur_pos + 1, new_pos, &reg_num, &offset) == false)
	return false;
	cur_pos_ = new_pos;
	dest->base_register_name_ = "regs[" + std::to_string(reg_num.value()) + "]";
	dest->deref_offset_ = offset;
	} else {
	// Parse ...@<value>
	optional<int> val;
	new_pos = parse_number(cur_pos, &val);
	if (cur_pos == new_pos)
	return error_return(cur_pos, cur_pos);
	cur_pos_ = new_pos;
	dest->constant_ = val;
	}

	skip_whitespace_from(cur_pos_);
	return true;
	}

	bool ArgumentParser_powerpc64::parse(Argument *dest) {
	if (done())
	return false;

	bool matched;
	std::smatch matches;
	std::string arg_str(&arg_[cur_pos_]);
	std::regex arg_n_regex("^(\\-?[1248])\\@");
	// Operands with constants of form iNUM or i-NUM
	std::regex arg_op_regex_const("^i(\\-?[0-9]+)( +\|$)");
	// Operands with register only of form REG or %rREG
	std::regex arg_op_regex_reg("^(?:%r)?([1-2]?[0-9]\|3[0-1])( +\|$)");
	// Operands with a base register and an offset of form
	// NUM(REG) or -NUM(REG) or NUM(%rREG) or -NUM(%rREG)
	std::regex arg_op_regex_breg_off(
	"^(\\-?[0-9]+)\\((?:%r)?([1-2]?[0-9]\|3[0-1])\\)( +\|$)");
	// Operands with a base register and an index register
	// of form REG,REG or %rREG,%rREG
	std::regex arg_op_regex_breg_ireg(
	"^(?:%r)?([1-2]?[0-9]\|3[0-1])\\,(?:%r)?([1-2]?[0-9]\|3[0-1])( +\|$)");

	matched = std::regex_search(arg_str, matches, arg_n_regex);
	if (matched) {
	dest->arg_size_ = stoi(matches.str(1));
	cur_pos_ += matches.length(0);
	arg_str = &arg_[cur_pos_];

	if (std::regex_search(arg_str, matches, arg_op_regex_const)) {
	dest->constant_ = stoi(matches.str(1));
	} else if (std::regex_search(arg_str, matches, arg_op_regex_reg)) {
	dest->base_register_name_ = "gpr[" + matches.str(1) + "]";
	} else if (std::regex_search(arg_str, matches, arg_op_regex_breg_off)) {
	dest->deref_offset_ = stoi(matches.str(1));
	dest->base_register_name_ = "gpr[" + matches.str(2) + "]";
	} else if (std::regex_search(arg_str, matches, arg_op_regex_breg_ireg)) {
	dest->deref_offset_ = 0; // In powerpc64, such operands contain a base
	// register and an index register which are
	// part of an indexed load/store operation.
	// Even if no offset value is present, this
	// is required by Argument::assign_to_local()
	// in order to generate code for reading the
	// argument. So, this is set to zero.
	dest->base_register_name_ = "gpr[" + matches.str(1) + "]";
	dest->index_register_name_ = "gpr[" + matches.str(2) + "]";
	dest->scale_ = abs(*dest->arg_size_);
	} else {
	matched = false;
	}
	}

	if (!matched) {
	print_error(cur_pos_);
	skip_until_whitespace_from(cur_pos_);
	skip_whitespace_from(cur_pos_);
	return false;
	}

	cur_pos_ += matches.length(0);
	skip_whitespace_from(cur_pos_);
	return true;
	}

	ssize_t ArgumentParser_x64::parse_identifier(ssize_t pos,
	optional<std::string> *result) {
	if (isalpha(arg_[pos]) \|\| arg_[pos] == '_') {
	ssize_t start = pos++;
	while (isalnum(arg_[pos]) \|\| arg_[pos] == '_') pos++;
	if (pos - start)
	result->emplace(arg_ + start, pos - start);
	}
	return pos;
	}

	ssize_t ArgumentParser_x64::parse_register(ssize_t pos, std::string &name,
	int &size) {
	ssize_t start = ++pos;
	if (arg_[start - 1] != '%')
	return -start;

	while (isalnum(arg_[pos])) pos++;

	std::string regname(arg_ + start, pos - start);
	if (!normalize_register(&regname, &size))
	return -start;

	name = regname;
	return pos;
	}

	ssize_t ArgumentParser_x64::parse_base_register(ssize_t pos, Argument *dest) {
	int size;
	std::string name;
	ssize_t res = parse_register(pos, name, size);
	if (res < 0)
	return res;

	dest->base_register_name_ = name;
	if (!dest->arg_size_)
	dest->arg_size_ = size;

	return res;
	}

	ssize_t ArgumentParser_x64::parse_index_register(ssize_t pos, Argument *dest) {
	int size;
	std::string name;
	ssize_t res = parse_register(pos, name, size);
	if (res < 0)
	return res;

	dest->index_register_name_ = name;

	return res;
	}

	ssize_t ArgumentParser_x64::parse_scale(ssize_t pos, Argument *dest) {
	return parse_number(pos, &dest->scale_);
	}

	ssize_t ArgumentParser_x64::parse_expr(ssize_t pos, Argument *dest) {
	if (arg_[pos] == '$')
	return parse_number(pos + 1, &dest->constant_);

	if (arg_[pos] == '%')
	return parse_base_register(pos, dest);

	if (isdigit(arg_[pos]) \|\| arg_[pos] == '-') {
	pos = parse_number(pos, &dest->deref_offset_);
	if (arg_[pos] == '+') {
	pos = parse_identifier(pos + 1, &dest->deref_ident_);
	if (!dest->deref_ident_)
	return -pos;
	}
	} else {
	dest->deref_offset_ = 0;
	pos = parse_identifier(pos, &dest->deref_ident_);
	if (arg_[pos] == '+' \|\| arg_[pos] == '-') {
	pos = parse_number(pos, &dest->deref_offset_);
	}
	}

	if (arg_[pos] != '(')
	return -pos;

	pos = parse_base_register(pos + 1, dest);
	if (pos < 0)
	return pos;

	if (arg_[pos] == ',') {
	pos = parse_index_register(pos + 1, dest);
	if (pos < 0)
	return pos;

	if (arg_[pos] == ',') {
	pos = parse_scale(pos + 1, dest);
	if (pos < 0)
	return pos;
	}
	}

	return (arg_[pos] == ')') ? pos + 1 : -pos;
	}

	ssize_t ArgumentParser_x64::parse_1(ssize_t pos, Argument *dest) {
	if (isdigit(arg_[pos]) \|\| arg_[pos] == '-') {
	optional<int> asize;
	ssize_t m = parse_number(pos, &asize);
	if (arg_[m] == '@' && asize) {
	dest->arg_size_ = asize;
	return parse_expr(m + 1, dest);
	}
	}
	return parse_expr(pos, dest);
	}

	bool ArgumentParser_x64::parse(Argument *dest) {
	if (done())
	return false;

	ssize_t res = parse_1(cur_pos_, dest);
	if (res < 0)
	return error_return(-res, -res + 1);
	if (!isspace(arg_[res]) && arg_[res] != '\0')
	return error_return(res, res);
	skip_whitespace_from(res);
	return true;
	}

	const std::unordered_map<std::string, ArgumentParser_x64::RegInfo>
	ArgumentParser_x64::registers_ = {
	{"rax", {REG_A, 8}}, {"eax", {REG_A, 4}},
	{"ax", {REG_A, 2}}, {"al", {REG_A, 1}},

	{"rbx", {REG_B, 8}}, {"ebx", {REG_B, 4}},
	{"bx", {REG_B, 2}}, {"bl", {REG_B, 1}},

	{"rcx", {REG_C, 8}}, {"ecx", {REG_C, 4}},
	{"cx", {REG_C, 2}}, {"cl", {REG_C, 1}},

	{"rdx", {REG_D, 8}}, {"edx", {REG_D, 4}},
	{"dx", {REG_D, 2}}, {"dl", {REG_D, 1}},

	{"rsi", {REG_SI, 8}}, {"esi", {REG_SI, 4}},
	{"si", {REG_SI, 2}}, {"sil", {REG_SI, 1}},

	{"rdi", {REG_DI, 8}}, {"edi", {REG_DI, 4}},
	{"di", {REG_DI, 2}}, {"dil", {REG_DI, 1}},

	{"rbp", {REG_BP, 8}}, {"ebp", {REG_BP, 4}},
	{"bp", {REG_BP, 2}}, {"bpl", {REG_BP, 1}},

	{"rsp", {REG_SP, 8}}, {"esp", {REG_SP, 4}},
	{"sp", {REG_SP, 2}}, {"spl", {REG_SP, 1}},

	{"r8", {REG_8, 8}}, {"r8d", {REG_8, 4}},
	{"r8w", {REG_8, 2}}, {"r8b", {REG_8, 1}},

	{"r9", {REG_9, 8}}, {"r9d", {REG_9, 4}},
	{"r9w", {REG_9, 2}}, {"r9b", {REG_9, 1}},

	{"r10", {REG_10, 8}}, {"r10d", {REG_10, 4}},
	{"r10w", {REG_10, 2}}, {"r10b", {REG_10, 1}},

	{"r11", {REG_11, 8}}, {"r11d", {REG_11, 4}},
	{"r11w", {REG_11, 2}}, {"r11b", {REG_11, 1}},

	{"r12", {REG_12, 8}}, {"r12d", {REG_12, 4}},
	{"r12w", {REG_12, 2}}, {"r12b", {REG_12, 1}},

	{"r13", {REG_13, 8}}, {"r13d", {REG_13, 4}},
	{"r13w", {REG_13, 2}}, {"r13b", {REG_13, 1}},

	{"r14", {REG_14, 8}}, {"r14d", {REG_14, 4}},
	{"r14w", {REG_14, 2}}, {"r14b", {REG_14, 1}},

	{"r15", {REG_15, 8}}, {"r15d", {REG_15, 4}},
	{"r15w", {REG_15, 2}}, {"r15b", {REG_15, 1}},

	{"rip", {REG_RIP, 8}},
	};

	void ArgumentParser_x64::reg_to_name(std::string *norm, Register reg) {
	switch (reg) {
	case REG_A:
	*norm = "ax";
	break;
	case REG_B:
	*norm = "bx";
	break;
	case REG_C:
	*norm = "cx";
	break;
	case REG_D:
	*norm = "dx";
	break;

	case REG_SI:
	*norm = "si";
	break;
	case REG_DI:
	*norm = "di";
	break;
	case REG_BP:
	*norm = "bp";
	break;
	case REG_SP:
	*norm = "sp";
	break;

	case REG_8:
	*norm = "r8";
	break;
	case REG_9:
	*norm = "r9";
	break;
	case REG_10:
	*norm = "r10";
	break;
	case REG_11:
	*norm = "r11";
	break;
	case REG_12:
	*norm = "r12";
	break;
	case REG_13:
	*norm = "r13";
	break;
	case REG_14:
	*norm = "r14";
	break;
	case REG_15:
	*norm = "r15";
	break;

	case REG_RIP:
	*norm = "ip";
	break;
	}
	}

	bool ArgumentParser_x64::normalize_register(std::string reg, int reg_size) {
	auto it = registers_.find(*reg);
	if (it == registers_.end())
	return false;

	*reg_size = it->second.size;
	reg_to_name(reg, it->second.reg);
	return true;
	}
	}