ProcSyms: deduplicate symbol names (iovisor#598)

linux-kern · Jul 8, 2016 · 966edb2 · 966edb2
1 parent 5256154
commit 966edb2
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Showing 2 changed files with 9 additions and 6 deletions.
diff --git a/src/cc/bcc_syms.cc b/src/cc/bcc_syms.cc
@@ -132,7 +132,8 @@ bool ProcSyms::resolve_name(const char *module, const char *name,
 int ProcSyms::Module::_add_symbol(const char *symname, uint64_t start,
  uint64_t end, int flags, void *p) {
  Module *m = static_cast<Module *>(p);
- m->syms_.emplace_back(symname, start, end, flags);
+ auto res = m->symnames_.emplace(symname);
+ m->syms_.emplace_back(&*(res.first), start, end, flags);
  return 0;
 }
 
@@ -160,7 +161,7 @@ bool ProcSyms::Module::find_name(const char *symname, uint64_t *addr) {
  load_sym_table();
 
  for (Symbol &s : syms_) {
- if (s.name == symname) {
+ if (*(s.name) == symname) {
  *addr = is_so() ? start_ + s.start : s.start;
  return true;
  }
@@ -176,15 +177,15 @@ bool ProcSyms::Module::find_addr(uint64_t addr, struct bcc_symbol *sym) {
  sym->module = name_.c_str();
  sym->offset = offset;
 
- auto it = std::upper_bound(syms_.begin(), syms_.end(), Symbol("", offset, 0));
+ auto it = std::upper_bound(syms_.begin(), syms_.end(), Symbol(nullptr, offset, 0));
  if (it != syms_.begin())
  --it;
  else
  it = syms_.end();
 
  if (it != syms_.end()
  && offset >= it->start && offset < it->start + it->size) {
- sym->name = it->name.c_str();
+ sym->name = it->name->c_str();
  sym->offset = (offset - it->start);
  return true;
  }

diff --git a/src/cc/syms.h b/src/cc/syms.h
@@ -18,6 +18,7 @@
 #include <algorithm>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <vector>
 
 #include <sys/types.h>
@@ -63,9 +64,9 @@ class KSyms : SymbolCache {
 
 class ProcSyms : SymbolCache {
  struct Symbol {
- Symbol(const char *name, uint64_t start, uint64_t size, int flags = 0)
+ Symbol(const std::string *name, uint64_t start, uint64_t size, int flags = 0)
  : name(name), start(start), size(size), flags(flags) {}
- std::string name;
+ const std::string *name;
  uint64_t start;
  uint64_t size;
  int flags;
@@ -81,6 +82,7 @@ class ProcSyms : SymbolCache {
  std::string name_;
  uint64_t start_;
  uint64_t end_;
+ std::unordered_set<std::string> symnames_;
  std::vector<Symbol> syms_;
 
  void load_sym_table();