Address code review

src/cc/bcc_elf.c

@@ -291,7 +291,7 @@ static int list_in_scn(Elf *e, Elf_Scn *section, size_t stridx, size_t symsize,
 #endif
 
       int ret;
-      if (callback_lazy)
+      if (option->lazy_symbolize)
         ret = callback_lazy(stridx, sym.st_name, name_len, sym.st_value,
                             sym.st_size, debugfile, payload);
       else
@@ -585,14 +585,16 @@ static int foreach_sym_core(const char *path, bcc_elf_symcb callback,
 
 int bcc_elf_foreach_sym(const char *path, bcc_elf_symcb callback,
                         void *option, void *payload) {
-  return foreach_sym_core(
-      path, callback, NULL, (struct bcc_symbol_option*)option, payload, 0);
+  struct bcc_symbol_option *o = option;
+  o->lazy_symbolize = 0;
+  return foreach_sym_core(path, callback, NULL, o, payload, 0);
 }
 
 int bcc_elf_foreach_sym_lazy(const char *path, bcc_elf_symcb_lazy callback,
                         void *option, void *payload) {
-  return foreach_sym_core(path, NULL, callback,
-      (struct bcc_symbol_option*)option, payload, 0);
+  struct bcc_symbol_option *o = option;
+  o->lazy_symbolize = 1;
+  return foreach_sym_core(path, NULL, callback, o, payload, 0);
 }
 
 int bcc_elf_get_text_scn_info(const char *path, uint64_t *addr,

src/cc/bcc_syms.cc

@@ -110,6 +110,7 @@ ProcSyms::ProcSyms(int pid, struct bcc_symbol_option *option)
     symbol_option_ = {
       .use_debug_file = 1,
       .check_debug_file_crc = 1,
+      .lazy_symbolize = 0,
       .use_symbol_type = (1 << STT_FUNC) | (1 << STT_GNU_IFUNC)
     };
   load_modules();
@@ -294,8 +295,12 @@ void ProcSyms::Module::load_sym_table() {
 
   if (type_ == ModuleType::PERF_MAP)
     bcc_perf_map_foreach_sym(path_.c_str(), _add_symbol, this);
-  if (type_ == ModuleType::EXEC || type_ == ModuleType::SO)
-    bcc_elf_foreach_sym_lazy(path_.c_str(), _add_symbol_lazy, symbol_option_, this);
+  if (type_ == ModuleType::EXEC || type_ == ModuleType::SO) {
+    if (symbol_option_->lazy_symbolize)
+      bcc_elf_foreach_sym_lazy(path_.c_str(), _add_symbol_lazy, symbol_option_, this);
+    else
+      bcc_elf_foreach_sym(path_.c_str(), _add_symbol, symbol_option_, this);
+  }
   if (type_ == ModuleType::VDSO)
     bcc_elf_foreach_vdso_sym(_add_symbol, this);
 
@@ -399,18 +404,19 @@ bool ProcSyms::Module::find_addr(uint64_t offset, struct bcc_symbol *sym) {
   for (; offset >= it->start; --it) {
     if (offset < it->start + it->size) {
       // Resolve and cache the symbol name if necessary
-      if (!it->name) {
+      if (!it->is_name_resolved) {
         ProcMountNSGuard g(mount_ns_);
-        std::string sym_name(it->name_idx.str_len + 1, '\0');
-        if (bcc_elf_symbol_str(name_.c_str(), it->name_idx.section_idx,
-              it->name_idx.str_table_idx, &sym_name[0], sym_name.size(),
-              it->name_idx.debugfile))
+        std::string sym_name(it->data.name_idx.str_len + 1, '\0');
+        if (bcc_elf_symbol_str(name_.c_str(), it->data.name_idx.section_idx,
+              it->data.name_idx.str_table_idx, &sym_name[0], sym_name.size(),
+              it->data.name_idx.debugfile))
           break;
 
-        it->name = &*(symnames_.emplace(std::move(sym_name)).first);
+        it->data.name = &*(symnames_.emplace(std::move(sym_name)).first);
+        it->is_name_resolved = true;
       }
 
-      sym->name = it->name->c_str();
+      sym->name = it->data.name->c_str();
       sym->offset = (offset - it->start);
       return true;
     }
@@ -667,6 +673,7 @@ int bcc_foreach_function_symbol(const char *module, SYM_CB cb) {
   static struct bcc_symbol_option default_option = {
     .use_debug_file = 1,
     .check_debug_file_crc = 1,
+    .lazy_symbolize = 0,
     .use_symbol_type = (1 << STT_FUNC) | (1 << STT_GNU_IFUNC)
   };
 
@@ -705,6 +712,7 @@ int bcc_resolve_symname(const char *module, const char *symname,
   static struct bcc_symbol_option default_option = {
     .use_debug_file = 1,
     .check_debug_file_crc = 1,
+    .lazy_symbolize = 0,
 #if defined(__powerpc64__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
     .use_symbol_type = BCC_SYM_ALL_TYPES | (1 << STT_PPC64LE_SYM_LEP),
 #else

src/cc/bcc_syms.h

@@ -47,6 +47,8 @@ static const uint32_t BCC_SYM_ALL_TYPES = 65535;
 struct bcc_symbol_option {
   int use_debug_file;
   int check_debug_file_crc;
+  // Symbolize on-demand or symbolize everything ahead of time
+  int lazy_symbolize;
   // Bitmask flags indicating what types of ELF symbols to use
   uint32_t use_symbol_type;
 };

src/cc/syms.h

@@ -78,17 +78,22 @@ class ProcSyms : SymbolCache {
 
   struct Symbol {
     Symbol(const std::string *name, uint64_t start, uint64_t size)
-        : name(name), start(start), size(size) {}
+        : is_name_resolved(true), start(start), size(size) {
+      data.name = name;
+    }
     Symbol(size_t section_idx, size_t str_table_idx, size_t str_len, uint64_t start,
            uint64_t size, bool debugfile)
-        : start(start), size(size) {
-      name_idx.section_idx = section_idx;
-      name_idx.str_table_idx = str_table_idx;
-      name_idx.str_len = str_len;
-      name_idx.debugfile = debugfile;
+        : is_name_resolved(false), start(start), size(size) {
+      data.name_idx.section_idx = section_idx;
+      data.name_idx.str_table_idx = str_table_idx;
+      data.name_idx.str_len = str_len;
+      data.name_idx.debugfile = debugfile;
     }
-    struct NameIdx name_idx;
-    const std::string *name{nullptr};
+    bool is_name_resolved;
+    union {
+      struct NameIdx name_idx;
+      const std::string *name{nullptr};
+    } data;
     uint64_t start;
     uint64_t size;