1 files changed, 209 insertions, 0 deletions
diff --git a/lib/System/DynamicLibrary.cpp b/lib/System/DynamicLibrary.cpp
new file mode 100644
index 0000000..8119348
--- /dev/null
+++ b/lib/System/DynamicLibrary.cpp
@@ -0,0 +1,209 @@
+//===-- DynamicLibrary.cpp - Runtime link/load libraries --------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Reid Spencer and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+//  This header file implements the operating system DynamicLibrary concept.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/System/DynamicLibrary.h"
+#include "llvm/Config/config.h"
+#include <map>
+
+// Collection of symbol name/value pairs to be searched prior to any libraries.
+static std::map<std::string, void *> g_symbols;
+
+void llvm::sys::DynamicLibrary::AddSymbol(const char* symbolName,
+                                          void *symbolValue) {
+  g_symbols[symbolName] = symbolValue;
+}
+
+// It is not possible to use ltdl.c on VC++ builds as the terms of its LGPL
+// license and special exception would cause all of LLVM to be placed under
+// the LGPL.  This is because the exception applies only when libtool is
+// used, and obviously libtool is not used with Visual Studio.  An entirely
+// separate implementation is provided in win32/DynamicLibrary.cpp.
+
+#ifdef LLVM_ON_WIN32
+
+#include "Win32/DynamicLibrary.inc"
+
+#else
+
+#include "ltdl.h"
+#include <cassert>
+using namespace llvm;
+using namespace llvm::sys;
+
+//===----------------------------------------------------------------------===//
+//=== WARNING: Implementation here must contain only TRULY operating system
+//===          independent code.
+//===----------------------------------------------------------------------===//
+
+static inline void check_ltdl_initialization() {
+  static bool did_initialize_ltdl = false;
+  if (!did_initialize_ltdl) {
+    int Err = lt_dlinit();
+    Err = Err; // Silence warning.
+    assert(0 == Err && "Can't init the ltdl library");
+    did_initialize_ltdl = true;
+  }
+}
+
+static std::vector<lt_dlhandle> OpenedHandles;
+
+DynamicLibrary::DynamicLibrary() : handle(0) {
+  check_ltdl_initialization();
+
+  lt_dlhandle a_handle = lt_dlopen(0);
+
+  assert(a_handle == 0 || "Can't open program as dynamic library");
+
+  handle = a_handle;
+  OpenedHandles.push_back(a_handle);
+}
+
+/*
+DynamicLibrary::DynamicLibrary(const char*filename) : handle(0) {
+  check_ltdl_initialization();
+
+  lt_dlhandle a_handle = lt_dlopen(filename);
+
+  if (a_handle == 0)
+    a_handle = lt_dlopenext(filename);
+
+  if (a_handle == 0)
+    throw std::string("Can't open :") + filename + ": " + lt_dlerror();
+
+  handle = a_handle;
+  OpenedHandles.push_back(a_handle);
+}
+*/
+
+DynamicLibrary::~DynamicLibrary() {
+  lt_dlhandle a_handle = (lt_dlhandle) handle;
+  if (a_handle) {
+    lt_dlclose(a_handle);
+
+    for (std::vector<lt_dlhandle>::iterator I = OpenedHandles.begin(),
+         E = OpenedHandles.end(); I != E; ++I) {
+      if (*I == a_handle) {
+        // Note: don't use the swap/pop_back trick here. Order is important.
+        OpenedHandles.erase(I);
+        return;
+      }
+    }
+  }
+}
+
+bool DynamicLibrary::LoadLibraryPermanently(const char *Filename,
+                                            std::string *ErrMsg) {
+  check_ltdl_initialization();
+  lt_dlhandle a_handle = lt_dlopen(Filename);
+
+  if (a_handle == 0)
+    a_handle = lt_dlopenext(Filename);
+
+  if (a_handle == 0) {
+    if (ErrMsg)
+      *ErrMsg = std::string("Can't open :") +
+          (Filename ? Filename : "<current process>") + ": " + lt_dlerror();
+    return true;
+  }
+
+  lt_dlmakeresident(a_handle);
+
+  OpenedHandles.push_back(a_handle);
+  return false;
+}
+
+void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
+  check_ltdl_initialization();
+
+  // First check symbols added via AddSymbol().
+  std::map<std::string, void *>::iterator I = g_symbols.find(symbolName);
+  if (I != g_symbols.end())
+    return I->second;
+
+  // Now search the libraries.
+  for (std::vector<lt_dlhandle>::iterator I = OpenedHandles.begin(),
+       E = OpenedHandles.end(); I != E; ++I) {
+    lt_ptr ptr = lt_dlsym(*I, symbolName);
+    if (ptr)
+      return ptr;
+  }
+
+  // If this is darwin, it has some funky issues, try to solve them here.  Some
+  // important symbols are marked 'private external' which doesn't allow
+  // SearchForAddressOfSymbol to find them.  As such, we special case them here,
+  // there is only a small handful of them.
+
+#ifdef __APPLE__
+#define EXPLICIT_SYMBOL(SYM) \
+   extern void *SYM; if (!strcmp(symbolName, #SYM)) return &SYM
+  {
+    EXPLICIT_SYMBOL(__ashldi3);
+    EXPLICIT_SYMBOL(__ashrdi3);
+    EXPLICIT_SYMBOL(__cmpdi2);
+    EXPLICIT_SYMBOL(__divdi3);
+    EXPLICIT_SYMBOL(__eprintf);
+    EXPLICIT_SYMBOL(__fixdfdi);
+    EXPLICIT_SYMBOL(__fixsfdi);
+    EXPLICIT_SYMBOL(__fixunsdfdi);
+    EXPLICIT_SYMBOL(__fixunssfdi);
+    EXPLICIT_SYMBOL(__floatdidf);
+    EXPLICIT_SYMBOL(__floatdisf);
+    EXPLICIT_SYMBOL(__lshrdi3);
+    EXPLICIT_SYMBOL(__moddi3);
+    EXPLICIT_SYMBOL(__udivdi3);
+    EXPLICIT_SYMBOL(__umoddi3);
+  }
+#undef EXPLICIT_SYMBOL
+#endif
+
+// 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__)
+  {
+    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;
+}
+
+void *DynamicLibrary::GetAddressOfSymbol(const char *symbolName) {
+  assert(handle != 0 && "Invalid DynamicLibrary handle");
+  return lt_dlsym((lt_dlhandle) handle, symbolName);
+}
+
+#endif // LLVM_ON_WIN32
+
+DEFINING_FILE_FOR(SystemDynamicLibrary)