Use DynamicLibrary instances as a way to get symbols from a specific library. Preparation for upcoming (preliminary) support for plugins for the static analyzer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137791 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/DynamicLibrary.cpp b/lib/Support/DynamicLibrary.cpp
index 455c380..63298b9 100644
--- a/lib/Support/DynamicLibrary.cpp
+++ b/lib/Support/DynamicLibrary.cpp
@@ -9,28 +9,26 @@
 //
 //  This header file implements the operating system DynamicLibrary concept.
 //
-// FIXME: This file leaks the ExplicitSymbols and OpenedHandles vector, and is
-// not thread safe!
+// FIXME: This file leaks ExplicitSymbols and OpenedHandles!
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/DenseSet.h"
 #include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/Mutex.h"
 #include "llvm/Config/config.h"
 #include <cstdio>
 #include <cstring>
-#include <map>
-#include <vector>
 
 // Collection of symbol name/value pairs to be searched prior to any libraries.
-static std::map<std::string, void*> *ExplicitSymbols = 0;
+static llvm::StringMap<void *> *ExplicitSymbols = 0;
 
 namespace {
 
 struct ExplicitSymbolsDeleter {
   ~ExplicitSymbolsDeleter() {
-    if (ExplicitSymbols)
-      delete ExplicitSymbols;
+    delete ExplicitSymbols;
   }
 };
 
@@ -38,10 +36,17 @@
 
 static ExplicitSymbolsDeleter Dummy;
 
-void llvm::sys::DynamicLibrary::AddSymbol(const char* symbolName,
+
+static llvm::sys::SmartMutex<true>& getMutex() {
+  static llvm::sys::SmartMutex<true> HandlesMutex;
+  return HandlesMutex;
+}
+
+void llvm::sys::DynamicLibrary::AddSymbol(StringRef symbolName,
                                           void *symbolValue) {
+  SmartScopedLock<true> lock(getMutex());
   if (ExplicitSymbols == 0)
-    ExplicitSymbols = new std::map<std::string, void*>();
+    ExplicitSymbols = new llvm::StringMap<void*>();
   (*ExplicitSymbols)[symbolName] = symbolValue;
 }
 
@@ -61,66 +66,77 @@
 //===          independent code.
 //===----------------------------------------------------------------------===//
 
-static std::vector<void *> *OpenedHandles = 0;
+static DenseSet<void *> *OpenedHandles = 0;
 
-
-static SmartMutex<true>& getMutex() {
-  static SmartMutex<true> HandlesMutex;
-  return HandlesMutex;
-}
-
-
-bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
-                                            std::string *ErrMsg) {
-  void *H = dlopen(Filename, RTLD_LAZY|RTLD_GLOBAL);
-  if (H == 0) {
-    if (ErrMsg) *ErrMsg = dlerror();
-    return true;
+DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
+                                                   std::string *errMsg) {
+  void *handle = dlopen(filename, RTLD_LAZY|RTLD_GLOBAL);
+  if (handle == 0) {
+    if (errMsg) *errMsg = dlerror();
+    return DynamicLibrary();
   }
+
 #ifdef __CYGWIN__
   // Cygwin searches symbols only in the main
   // with the handle of dlopen(NULL, RTLD_GLOBAL).
-  if (Filename == NULL)
-    H = RTLD_DEFAULT;
+  if (filename == NULL)
+    handle = RTLD_DEFAULT;
 #endif
-  SmartScopedLock<true> Lock(getMutex());
+
+  SmartScopedLock<true> lock(getMutex());
   if (OpenedHandles == 0)
-    OpenedHandles = new std::vector<void *>();
-  OpenedHandles->push_back(H);
-  return false;
+    OpenedHandles = new DenseSet<void *>();
+
+  // If we've already loaded this library, dlclose() the handle in order to
+  // keep the internal refcount at +1.
+  if (!OpenedHandles->insert(handle).second)
+    dlclose(handle);
+
+  return DynamicLibrary(handle);
 }
+
+void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
+  if (!isValid())
+    return NULL;
+  return dlsym(Data, symbolName);
+}
+
 #else
 
 using namespace llvm;
 using namespace llvm::sys;
 
-bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
-                                            std::string *ErrMsg) {
-  if (ErrMsg) *ErrMsg = "dlopen() not supported on this platform";
-  return true;
+DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
+                                                   std::string *errMsg) {
+  if (errMsg) *errMsg = "dlopen() not supported on this platform";
+  return DynamicLibrary();
 }
+
+void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
+  return NULL;
+}
+
 #endif
 
 namespace llvm {
 void *SearchForAddressOfSpecialSymbol(const char* symbolName);
 }
 
-void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
+void* DynamicLibrary::SearchForAddressOfSymbol(const char *symbolName) {
+  SmartScopedLock<true> Lock(getMutex());
+
   // First check symbols added via AddSymbol().
   if (ExplicitSymbols) {
-    std::map<std::string, void *>::iterator I =
-      ExplicitSymbols->find(symbolName);
-    std::map<std::string, void *>::iterator E = ExplicitSymbols->end();
+    StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
 
-    if (I != E)
-      return I->second;
+    if (i != ExplicitSymbols->end())
+      return i->second;
   }
 
 #if HAVE_DLFCN_H
   // Now search the libraries.
-  SmartScopedLock<true> Lock(getMutex());
   if (OpenedHandles) {
-    for (std::vector<void *>::iterator I = OpenedHandles->begin(),
+    for (DenseSet<void *>::iterator I = OpenedHandles->begin(),
          E = OpenedHandles->end(); I != E; ++I) {
       //lt_ptr ptr = lt_dlsym(*I, symbolName);
       void *ptr = dlsym(*I, symbolName);
diff --git a/lib/Support/Windows/DynamicLibrary.inc b/lib/Support/Windows/DynamicLibrary.inc
index fc5f580..6724fbc 100644
--- a/lib/Support/Windows/DynamicLibrary.inc
+++ b/lib/Support/Windows/DynamicLibrary.inc
@@ -39,7 +39,7 @@
 //===          and must not be UNIX code.
 //===----------------------------------------------------------------------===//
 
-static std::vector<HMODULE> OpenedHandles;
+static DenseSet<HMODULE> *OpenedHandles;
 
 extern "C" {
 
@@ -63,30 +63,43 @@
 #endif
         stricmp(ModuleName, "msvcrt20") != 0 &&
         stricmp(ModuleName, "msvcrt40") != 0) {
-      OpenedHandles.push_back((HMODULE)ModuleBase);
+      OpenedHandles->push_back((HMODULE)ModuleBase);
     }
     return TRUE;
   }
 }
 
-bool DynamicLibrary::LoadLibraryPermanently(const char *filename,
-                                            std::string *ErrMsg) {
-  if (filename) {
-    HMODULE a_handle = LoadLibrary(filename);
+DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
+                                                   std::string *errMsg) {
+  if (!filename) {
+    // When no file is specified, enumerate all DLLs and EXEs in the process.
+    SmartScopedLock<true> lock(getMutex());
+    if (OpenedHandles == 0)
+      OpenedHandles = new DenseSet<HMODULE>();
 
-    if (a_handle == 0)
-      return MakeErrMsg(ErrMsg, std::string(filename) + ": Can't open : ");
-
-    OpenedHandles.push_back(a_handle);
-  } else {
-    // When no file is specified, enumerate all DLLs and EXEs in the
-    // process.
     EnumerateLoadedModules(GetCurrentProcess(), ELM_Callback, 0);
+    // Dummy library that represents "search all handles".
+    // This is mostly to ensure that the return value still shows up as "valid".
+    return DynamicLibrary(&OpenedHandles);
+  }
+  
+  HMODULE a_handle = LoadLibrary(filename);
+
+  if (a_handle == 0) {
+    MakeErrMsg(ErrMsg, std::string(filename) + ": Can't open : ");
+    return DynamicLibrary();
   }
 
-  // Because we don't remember the handle, we will never free it; hence,
-  // it is loaded permanently.
-  return false;
+  SmartScopedLock<true> lock(getMutex());
+  if (OpenedHandles == 0)
+    OpenedHandles = new DenseSet<HMODULE>();
+
+  // If we've already loaded this library, FreeLibrary() the handle in order to
+  // keep the internal refcount at +1.
+  if (!OpenedHandles->insert(a_handle).second)
+    FreeLibrary(a_handle);
+
+  return DynamicLibrary(a_handle);
 }
 
 // Stack probing routines are in the support library (e.g. libgcc), but we don't
@@ -101,21 +114,24 @@
 #undef EXPLICIT_SYMBOL2
 
 void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
+  SmartScopedLock<true> Lock(getMutex());
+
   // First check symbols added via AddSymbol().
   if (ExplicitSymbols) {
-    std::map<std::string, void *>::iterator I =
-      ExplicitSymbols->find(symbolName);
-    std::map<std::string, void *>::iterator E = ExplicitSymbols->end();
-    if (I != E)
-      return I->second;
+    StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
+
+    if (i != ExplicitSymbols->end())
+      return i->second;
   }
 
   // Now search the libraries.
-  for (std::vector<HMODULE>::iterator I = OpenedHandles.begin(),
-       E = OpenedHandles.end(); I != E; ++I) {
-    FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);
-    if (ptr) {
-      return (void *)(intptr_t)ptr;
+  if (OpenedHandles) {
+    for (DenseSet<HMODULE>::iterator I = OpenedHandles->begin(),
+         E = OpenedHandles->end(); I != E; ++I) {
+      FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);
+      if (ptr) {
+        return (void *)(intptr_t)ptr;
+      }
     }
   }
 
@@ -134,4 +150,14 @@
   return 0;
 }
 
+
+void *DynamicLibrary::getAddressOfSymbol(const char *symbolName) {
+  if (!isValid())
+    return NULL;
+  if (Data == &OpenedHandles)
+    return SearchForAddressOfSymbol(symbolName);
+  return (void *)(intptr_t)GetProcAddress((HMODULE)Data, symbolName);
+}
+
+
 }