libGL_Guest.cpp

/*
$info$
tags: thunklibs|GL
desc: Handles glXGetProcAddress
$end_info$
*/

#define GL_GLEXT_PROTOTYPES 1
#define GLX_GLXEXT_PROTOTYPES 1

#include <GL/glx.h>
#include <GL/glxext.h>
#include <GL/gl.h>
#include <GL/glext.h>

#undef GL_ARB_viewport_array
#include "glcorearb.h"

#include <dlfcn.h>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <string_view>
#include <unordered_map>

#include "common/Guest.h"

#include "thunkgen_guest_libGL.inl"

typedef void voidFunc();

// Maps OpenGL API function names to the address of a guest function which is
// linked to the corresponding host function pointer
const std::unordered_map<std::string_view, uintptr_t /* guest function address */> HostPtrInvokers = std::invoke([]() {
#define PAIR(name, unused) Ret[#name] = reinterpret_cast<uintptr_t>(GetCallerForHostFunction(name));
  std::unordered_map<std::string_view, uintptr_t> Ret;
  FOREACH_internal_SYMBOL(PAIR);
  return Ret;
#undef PAIR
});

extern "C" {
voidFunc* glXGetProcAddress(const GLubyte* procname) {
  auto Ret = fexfn_pack_glXGetProcAddress(procname);
  if (!Ret) {
    return nullptr;
  }

  auto TargetFuncIt = HostPtrInvokers.find(reinterpret_cast<const char*>(procname));
  if (TargetFuncIt == HostPtrInvokers.end()) {
    std::string_view procname_s {reinterpret_cast<const char*>(procname)};
    // If glXGetProcAddress is querying itself, then we can just return itself.
    // Some games do this for unknown reasons.
    if (procname_s == "glXGetProcAddress" || procname_s == "glXGetProcAddressARB") {
      return reinterpret_cast<voidFunc*>(glXGetProcAddress);
    }

    // Extension found in host but not in our interface definition => Not fatal but warn about it
    // Some games query leaked GLES symbols but don't use them
    // glFrustrumf : ES 1.x function
    //  - Papers, Please
    //  - Dicey Dungeons
    fprintf(stderr, "glXGetProcAddress: not found %s\n", procname);
    return nullptr;
  }

  LinkAddressToFunction((uintptr_t)Ret, TargetFuncIt->second);
  return Ret;
}

voidFunc* glXGetProcAddressARB(const GLubyte* procname) {
  return glXGetProcAddress(procname);
}
}

// Wrapper around malloc() without noexcept specifiers
static void* malloc_wrapper(size_t size) {
  return malloc(size);
}

static void OnInit() {
  fexfn_pack_SetGuestMalloc((uintptr_t)malloc_wrapper, (uintptr_t)CallbackUnpack<decltype(malloc_wrapper)>::Unpack);
  fexfn_pack_SetGuestXSync((uintptr_t)XSync, (uintptr_t)CallbackUnpack<decltype(XSync)>::Unpack);
  fexfn_pack_SetGuestXGetVisualInfo((uintptr_t)XGetVisualInfo, (uintptr_t)CallbackUnpack<decltype(XGetVisualInfo)>::Unpack);
  fexfn_pack_SetGuestXDisplayString((uintptr_t)XDisplayString, (uintptr_t)CallbackUnpack<decltype(XDisplayString)>::Unpack);
}

// libGL.so must pull in libX11.so as a dependency. Referencing some libX11
// symbol here prevents the linker from optimizing away the unused dependency
auto implicit_libx11_dependency = XSetErrorHandler;

LOAD_LIB_INIT(libGL, OnInit)