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Fix 32-bit game crash: call hooked __stdcall functions with stdcall()

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SafetyHook's InlineHook::call() invokes the trampoline through a __cdecl
pointer (the compiler default on x86). The functions we hook are __stdcall
(IDXGISwapChain::Present/Present1, the WASAPI render interfaces, and the
WINAPI SwapBuffers/wglSwapBuffers), so on 32-bit both sides cleaned the
stack -> ESP imbalance -> Run-Time Check Failure #0 and an instant crash.
On x64 every convention collapses to one, so it only bit 32-bit games:
Slaps and Beans (Unity/Rewired, 32-bit D3D11) froze the moment the Present
hook ran. The user's "crashes as soon as a button is pressed" was the
Present, not the button.

Switch every __stdcall trampoline call to SafetyHook's stdcall() (a no-op
on x64). The XInput/focus hooks were unaffected because they never call
the trampoline -- they return synthesized data.

Reproduction + regression coverage:
- tools/input_probe (coop_input_probe): injects, reports a connected pad,
  toggles a button, and takes a disable_mask to bisect which subsystem
  affects a game. Isolated the freeze to the video subsystem live.
- hook_selftest_x86 + present_hook_test_x86: the x86 sub-build now builds
  and runs these (the x64 present_hook_test can't see a one-convention
  bug). present_hook_test_x86 drives a real swapchain through the
  trampoline -- it would hit RTC #0 before this fix.
- hook_selftest strengthened to exercise every loaded xinput DLL's full
  export set (GetState, ordinal-100 GetStateEx, GetCapabilities, rumble
  SetState) and to dump the SharedBlock layout.
- protocol.hpp: static_asserts lock the cross-bitness front-of-block
  offsets (verified byte-identical on x86 and x64).

README roadmap trimmed (this milestone done) and a lessons-learned note
added on the call()/stdcall() convention trap.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
BlackMark
2026-06-20 20:07:17 +02:00
parent 9977ad5d5a
commit 435ab9d30f
9 changed files with 528 additions and 164 deletions
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9
hook/src/present_hook.cpp
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@@ -232,7 +232,12 @@ HRESULT STDMETHODCALLTYPE hk_Present(IDXGISwapChain* sc, UINT sync_interval, UIN
{
capture_backbuffer(sc);
}
return g_hk_present.call<HRESULT>(sc, sync_interval, flags);
// stdcall(), NOT call(): IDXGISwapChain::Present is __stdcall, but SafetyHook's
// call() invokes the trampoline through a __cdecl pointer (the default on x86).
// On 32-bit that double-cleans the stack -> ESP imbalance -> Run-Time Check
// Failure #0 and an instant crash. On x64 the conventions collapse, so it only
// bit 32-bit games (e.g. Slaps and Beans froze the moment it presented).
return g_hk_present.stdcall<HRESULT>(sc, sync_interval, flags);
}
HRESULT STDMETHODCALLTYPE hk_Present1(IDXGISwapChain1* sc, UINT sync_interval, UINT flags,
@@ -248,7 +253,7 @@ HRESULT STDMETHODCALLTYPE hk_Present1(IDXGISwapChain1* sc, UINT sync_interval, U
{
capture_backbuffer(sc); // IDXGISwapChain1 derives from IDXGISwapChain
}
return g_hk_present1.call<HRESULT>(sc, sync_interval, flags, params);
return g_hk_present1.stdcall<HRESULT>(sc, sync_interval, flags, params); // __stdcall, see hk_Present
}
// Create a throwaway device + swapchain purely to read IDXGISwapChain::Present