Initial import of the Apple clang-425.0.24 branch

lib/Support/DynamicLibrary.cpp

@@ -0,0 +1,189 @@
+//===-- DynamicLibrary.cpp - Runtime link/load libraries --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This header file implements the operating system DynamicLibrary concept.
+//
+// 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>
+
+// Collection of symbol name/value pairs to be searched prior to any libraries.
+static llvm::StringMap<void *> *ExplicitSymbols = 0;
+
+namespace {
+
+struct ExplicitSymbolsDeleter {
+  ~ExplicitSymbolsDeleter() {
+    delete ExplicitSymbols;
+  }
+};
+
+}
+
+static ExplicitSymbolsDeleter Dummy;
+
+
+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 llvm::StringMap<void*>();
+  (*ExplicitSymbols)[symbolName] = symbolValue;
+}
+
+char llvm::sys::DynamicLibrary::Invalid = 0;
+
+#ifdef LLVM_ON_WIN32
+
+#include "Windows/DynamicLibrary.inc"
+
+#else
+
+#if HAVE_DLFCN_H
+#include <dlfcn.h>
+using namespace llvm;
+using namespace llvm::sys;
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only TRULY operating system
+//===          independent code.
+//===----------------------------------------------------------------------===//
+
+static DenseSet<void *> *OpenedHandles = 0;
+
+DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *filename,
+                                                   std::string *errMsg) {
+  SmartScopedLock<true> lock(getMutex());
+
+  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)
+    handle = RTLD_DEFAULT;
+#endif
+
+  if (OpenedHandles == 0)
+    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;
+
+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) {
+  SmartScopedLock<true> Lock(getMutex());
+
+  // First check symbols added via AddSymbol().
+  if (ExplicitSymbols) {
+    StringMap<void *>::iterator i = ExplicitSymbols->find(symbolName);
+
+    if (i != ExplicitSymbols->end())
+      return i->second;
+  }
+
+#if HAVE_DLFCN_H
+  // Now search the libraries.
+  if (OpenedHandles) {
+    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);
+      if (ptr) {
+        return ptr;
+      }
+    }
+  }
+#endif
+
+  if (void *Result = llvm::SearchForAddressOfSpecialSymbol(symbolName))
+    return Result;
+
+// This macro returns the address of a well-known, explicit symbol
+#define EXPLICIT_SYMBOL(SYM) \
+   if (!strcmp(symbolName, #SYM)) return &SYM
+
+// On linux we have a weird situation. The stderr/out/in symbols are both
+// macros and global variables because of standards requirements. So, we
+// boldly use the EXPLICIT_SYMBOL macro without checking for a #define first.
+#if defined(__linux__) and !defined(__ANDROID__)
+  {
+    EXPLICIT_SYMBOL(stderr);
+    EXPLICIT_SYMBOL(stdout);
+    EXPLICIT_SYMBOL(stdin);
+  }
+#else
+  // For everything else, we want to check to make sure the symbol isn't defined
+  // as a macro before using EXPLICIT_SYMBOL.
+  {
+#ifndef stdin
+    EXPLICIT_SYMBOL(stdin);
+#endif
+#ifndef stdout
+    EXPLICIT_SYMBOL(stdout);
+#endif
+#ifndef stderr
+    EXPLICIT_SYMBOL(stderr);
+#endif
+  }
+#endif
+#undef EXPLICIT_SYMBOL
+
+  return 0;
+}
+
+#endif // LLVM_ON_WIN32