PNaCl Dynamic Linking: Added portable dependencies to shared objects.

src/untrusted/pll_loader/pll_loader.h

 // Copyright 2016 The Native Client Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NATIVE_CLIENT_SRC_UNTRUSTED_PLL_LOADER_PLL_LOADER_H_
 #define NATIVE_CLIENT_SRC_UNTRUSTED_PLL_LOADER_PLL_LOADER_H_ 1
 
 #include <string>
 #include <unordered_set>
 #include <vector>
 
 #include "native_client/src/untrusted/pll_loader/pll_root.h"
 
 // This helper class wraps the PLLRoot data structure and provides methods
 // for accessing parts of PLLRoot.
 class PLLModule {
  public:
   explicit PLLModule(const PLLRoot *root) : root_(root) {}
 
   static uint32_t HashString(const char *sp);
 
-  const PLLRoot *root() { return root_; }
+  const PLLRoot *root() const { return root_; }

[Mark Seaborn, 2016/04/01 23:42:19]

Nit: The whole PLLModule object is stateless since it just wraps a pointer.  So
there's really no difference between a PLLModule and a "const PLLModule", so I
would recommend not using the latter.  Adding "const" to this method suggests
that the others aren't const, which would be misleading since that's not the
case.

[Sean Klein, 2016/04/02 00:50:33]

Got it. Const removed from this function. To compile, "module" in
"AddByFilename" has been made non-const.

 
   const char *GetExportedSymbolName(size_t i) {
     return root_->string_table + root_->exported_names[i];
   }
 
   const char *GetImportedSymbolName(size_t i) {
     return root_->string_table + root_->imported_names[i];
   }
 
   // If this function returns "false", the symbol is definitely not exported.
   // Otherwise, the symbol may or may not be exported. This is public so the
   // bloom filter can be tested.
   bool IsMaybeExported(uint32_t hash);
 
   void *GetExportedSym(const char *name);
   void *InstantiateTLSBlock();
 
  private:
   const PLLRoot *root_;
 };
 
 // ModuleSet represents a set of loaded PLLs.
 class ModuleSet {
  public:
   // Load a PLL by filename. Does not add the filename to a known set of loaded
   // modules, and will not de-duplicate loading modules.
-  void AddByFilename(const char *filename);
+  // Returns a pointer to the PLL's pso_root.

[Mark Seaborn, 2016/04/01 23:42:19]

Nit: Should return a PLLRoot* rather than void* then, surely?  Same below.

[Sean Klein, 2016/04/02 00:50:33]

Done.

+  void *AddByFilename(const char *filename);
 
   // Change the search path used by the linker when looking for PLLs by soname.
   void SetSonameSearchPath(const std::vector<std::string> &dir_list);
 
   // Load a PLL by soname and add the soname to the set of loaded modules.
-  void AddBySoname(const char *soname);
+  // Returns a pointer to the PLL's pso_root if it is loaded, NULL otherwise.
+  void *AddBySoname(const char *soname);
 
   // Looks up a symbol in the set of modules.  This does a linear search of
   // the modules, in the order that they were added using AddByFilename().
   void *GetSym(const char *name);
 
   // Applies relocations to the modules, resolving references between them.
   void ResolveRefs();
 
  private:
   // The search path used to look for "sonames".
   std::vector<std::string> search_path_;
   // An unordered set of "sonames" (to see if a module has been loaded).
   std::unordered_set<std::string> sonames_;
   std::vector<PLLModule> modules_;
 };
 
 #endif