Merge pull request iovisor#3991 from maqiao-mq/bugfix

bcc/usdt: fix parse double-reg-indirect addressing mode in arguments …

src/cc/usdt.h

@@ -127,8 +127,7 @@ class ArgumentParser_aarch64 : public ArgumentParser {
  private:
  bool parse_register(ssize_t pos, ssize_t &new_pos, std::string &reg_name);
  bool parse_size(ssize_t pos, ssize_t &new_pos, optional<int> *arg_size);
- bool parse_mem(ssize_t pos, ssize_t &new_pos, std::string &reg_name,
- optional<int> *offset);
+ bool parse_mem(ssize_t pos, ssize_t &new_pos, Argument *dest);
 
  public:
  bool parse(Argument *dest);

src/cc/usdt/usdt_args.cc

@@ -190,16 +190,27 @@ bool ArgumentParser_aarch64::parse_size(ssize_t pos, ssize_t &new_pos,
 }
 
 bool ArgumentParser_aarch64::parse_mem(ssize_t pos, ssize_t &new_pos,
- std::string &reg_name,
- optional<int> *offset) {
- if (parse_register(pos, new_pos, reg_name) == false)
+ Argument *dest) {
+ std::string base_reg_name, index_reg_name;
+
+ if (parse_register(pos, new_pos, base_reg_name) == false)
  return false;
+ dest->base_register_name_ = base_reg_name;
 
  if (arg_[new_pos] == ',') {
  pos = new_pos + 1;
- new_pos = parse_number(pos, offset);
- if (new_pos == pos)
- return error_return(pos, pos);
+ new_pos = parse_number(pos, &dest->deref_offset_);
+ if (new_pos == pos) {
+ // offset isn't a number, so it should be a reg,
+ // which looks like: -1@[x0, x1], rather than -1@[x0, 24]
+ skip_whitespace_from(pos);
+ pos = cur_pos_;
+ if (parse_register(pos, new_pos, index_reg_name) == false)
+ return error_return(pos, pos);
+ dest->index_register_name_ = index_reg_name;
+ dest->scale_ = 1;
+ dest->deref_offset_ = 0;
+ }
  }
  if (arg_[new_pos] != ']')
  return error_return(new_pos, new_pos);
@@ -214,6 +225,7 @@ bool ArgumentParser_aarch64::parse(Argument *dest) {
  // Support the following argument patterns:
  // [-]<size>@<value>, [-]<size>@<reg>, [-]<size>@[<reg>], or
  // [-]<size>@[<reg>,<offset>]
+ // [-]<size>@[<reg>,<index_reg>]
  ssize_t cur_pos = cur_pos_, new_pos;
  optional<int> arg_size;
 
@@ -236,14 +248,10 @@ bool ArgumentParser_aarch64::parse(Argument *dest) {
  cur_pos_ = new_pos;
  dest->base_register_name_ = reg_name;
  } else if (arg_[cur_pos] == '[') {
- // Parse ...@[<reg>] and ...@[<reg,<offset>]
- optional<int> offset = 0;
- std::string reg_name;
- if (parse_mem(cur_pos + 1, new_pos, reg_name, &offset) == false)
+ // Parse ...@[<reg>], ...@[<reg,<offset>] and ...@[<reg>,<index_reg>]
+ if (parse_mem(cur_pos + 1, new_pos, dest) == false)
  return false;
  cur_pos_ = new_pos;
- dest->base_register_name_ = reg_name;
- dest->deref_offset_ = offset;
  } else {
  // Parse ...@<value>
  optional<long long> val;