lib/System/Win32/DynamicLibrary.cpp

//===- Win32/DynamicLibrary.cpp - Win32 DL Implementation -------*- C++ -*-===//
// 
//                     The LLVM Compiler Infrastructure
//
// This file was developed by Jeff Cohen and is distributed under the 
// University of Illinois Open Source License. See LICENSE.TXT for details.
// 
//===----------------------------------------------------------------------===//
//
// This file provides the Win32 specific implementation of  DynamicLibrary.
//
//===----------------------------------------------------------------------===//

#include "Win32.h"
#include <dbghelp.h>

#pragma comment(lib, "dbghelp.lib")

namespace llvm {
using namespace sys;

//===----------------------------------------------------------------------===//
//=== WARNING: Implementation here must contain only Win32 specific code 
//===          and must not be UNIX code.
//===----------------------------------------------------------------------===//

static std::vector<HMODULE> OpenedHandles;

BOOL CALLBACK ELM_Callback(PSTR  ModuleName,
                           ULONG ModuleBase,
                           ULONG ModuleSize,
                           PVOID UserContext)
{
  OpenedHandles.push_back((HMODULE)ModuleBase);
  return TRUE;
}

DynamicLibrary::DynamicLibrary() : handle(0) {
  handle = GetModuleHandle(NULL);
  OpenedHandles.push_back((HMODULE)handle);
}

DynamicLibrary::DynamicLibrary(const char*filename) : handle(0) {
  HMODULE a_handle = LoadLibrary(filename);

  if (a_handle == 0)
    ThrowError(std::string(filename) + ": Can't open : ");

  handle = a_handle;
  OpenedHandles.push_back(a_handle);
}

DynamicLibrary::~DynamicLibrary() {
  if (handle == 0)
    return;

  // GetModuleHandle() does not increment the ref count, so we must not free
  // the handle to the executable.
  if (handle != GetModuleHandle(NULL))
    FreeLibrary((HMODULE)handle);
  handle = 0;

  for (std::vector<HMODULE>::iterator I = OpenedHandles.begin(),
       E = OpenedHandles.end(); I != E; ++I) {
    if (*I == handle) {
      // Note: don't use the swap/pop_back trick here. Order is important.
      OpenedHandles.erase(I);
    }
  }
}

void DynamicLibrary::LoadLibraryPermanently(const char* filename) {
  if (filename) {
    HMODULE a_handle = LoadLibrary(filename);

	if (a_handle == 0)
		ThrowError(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);
  }

  // Because we don't remember the handles, we will never free them; hence,
  // it is loaded permanently.
}

void* DynamicLibrary::SearchForAddressOfSymbol(const char* symbolName) {
  for (std::vector<HMODULE>::iterator I = OpenedHandles.begin(),
       E = OpenedHandles.end(); I != E; ++I) {
    FARPROC ptr = GetProcAddress((HMODULE)*I, symbolName);
    if (ptr)
      return ptr;
  }

  return 0;
}

void *DynamicLibrary::GetAddressOfSymbol(const char *symbolName) {
  assert(handle != 0 && "Invalid DynamicLibrary handle");
  return GetProcAddress((HMODULE)handle, symbolName);
}

}

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