Refactor memory management into wibo::heap

- Removes blockUpper2GB hack; we now start early in the process
  and reserve all (available) space in the lower 2GB address
  space, leaving the upper 2GB untouched for host code
- All virtual memory operations flow through wibo::heap for
  bookkeeping
- All guest code uses a guest mimalloc area + thread-local heaps
  reserved in the guest address space

.gitignore

@@ -19,3 +19,4 @@ venv/
 *.pyc
 *.pyo
 *.pyd
+.ruff_cache/

CMakeLists.txt

@@ -174,6 +174,7 @@ add_executable(wibo
     src/files.cpp
     src/handles.cpp
     src/loader.cpp
+    src/heap.cpp
     src/main.cpp
     src/modules.cpp
     src/processes.cpp
@@ -184,9 +185,10 @@ add_executable(wibo
 target_compile_definitions(wibo PRIVATE _GNU_SOURCE _FILE_OFFSET_BITS=64 _TIME_BITS=64)
 target_compile_features(wibo PRIVATE cxx_std_20)
 target_compile_options(wibo PRIVATE -Wall -Wextra)
+target_link_options(wibo PRIVATE -no-pie -Wl,--image-base=0x90000000)
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     target_compile_options(wibo PRIVATE -fno-pie -maccumulate-outgoing-args)
-    target_link_options(wibo PRIVATE -no-pie -maccumulate-outgoing-args)
+    target_link_options(wibo PRIVATE -maccumulate-outgoing-args)
 endif()
 target_include_directories(wibo PRIVATE dll src ${WIBO_GENERATED_HEADER_DIR})
 target_link_libraries(wibo PRIVATE mimalloc-obj atomic)

dll/crt.cpp

@@ -3,6 +3,7 @@
 #include "common.h"
 #include "context.h"
 #include "crt_trampolines.h"
+#include "heap.h"
 #include "kernel32/internal.h"
 #include "modules.h"
 
@@ -180,25 +181,25 @@ const char *CDECL strrchr(const char *str, int ch) {
 void *CDECL malloc(SIZE_T size) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("malloc(%zu)\n", size);
-	return ::malloc(size);
+	return wibo::heap::guestMalloc(size);
 }
 
 void *CDECL calloc(SIZE_T count, SIZE_T size) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("calloc(%zu, %zu)\n", count, size);
-	return ::calloc(count, size);
+	return wibo::heap::guestCalloc(count, size);
 }
 
 void *CDECL realloc(void *ptr, SIZE_T newSize) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("realloc(%p, %zu)\n", ptr, newSize);
-	return ::realloc(ptr, newSize);
+	return wibo::heap::guestRealloc(ptr, newSize);
 }
 
 void CDECL free(void *ptr) {
 	HOST_CONTEXT_GUARD();
 	VERBOSE_LOG("free(%p)\n", ptr);
-	::free(ptr);
+	wibo::heap::guestFree(ptr);
 }
 
 void *CDECL memcpy(void *dest, const void *src, SIZE_T count) {

dll/kernel32/heapapi.cpp

@@ -1,4 +1,5 @@
 #include "heapapi.h"
+#include "heap.h"
 
 #include "common.h"
 #include "context.h"
@@ -22,8 +23,7 @@ HeapObject *g_processHeapRecord = nullptr;
 
 void ensureProcessHeapInitialized() {
 	std::call_once(g_processHeapInitFlag, []() {
-		mi_heap_t *heap = mi_heap_get_default();
+		auto record = make_pin<HeapObject>(nullptr);
-		auto record = make_pin<HeapObject>(heap);
 		if (!record) {
 			return;
 		}
@@ -38,9 +38,13 @@ bool isExecutableHeap(const HeapObject *record) {
 }
 
 LPVOID heapAllocFromRecord(HeapObject *record, DWORD dwFlags, SIZE_T dwBytes) {
-	if (!record || !record->heap) {
+	if (!record) {
 		return nullptr;
 	}
+	auto *heap = record->heap;
+	if (!heap && record->isProcessHeap) {
+		heap = wibo::heap::getGuestHeap();
+	}
 	if ((record->createFlags | dwFlags) & HEAP_GENERATE_EXCEPTIONS) {
 		DEBUG_LOG("HeapAlloc: HEAP_GENERATE_EXCEPTIONS not supported\n");
 		kernel32::setLastError(ERROR_INVALID_PARAMETER);
@@ -48,7 +52,7 @@ LPVOID heapAllocFromRecord(HeapObject *record, DWORD dwFlags, SIZE_T dwBytes) {
 	}
 	const bool zeroMemory = (dwFlags & HEAP_ZERO_MEMORY) != 0;
 	const SIZE_T requestSize = std::max<SIZE_T>(1, dwBytes);
-	void *mem = zeroMemory ? mi_heap_zalloc(record->heap, requestSize) : mi_heap_malloc(record->heap, requestSize);
+	void *mem = zeroMemory ? mi_heap_zalloc(heap, requestSize) : mi_heap_malloc(heap, requestSize);
 	if (!mem) {
 		kernel32::setLastError(ERROR_NOT_ENOUGH_MEMORY);
 		return nullptr;
@@ -63,9 +67,7 @@ LPVOID heapAllocFromRecord(HeapObject *record, DWORD dwFlags, SIZE_T dwBytes) {
 
 HeapObject::~HeapObject() {
 	if (heap) {
-		if (!isProcessHeap) {
+		mi_heap_destroy(heap);
-			mi_heap_destroy(heap);
-		}
 		heap = nullptr;
 	}
 	if (isProcessHeap) {
@@ -84,7 +86,7 @@ HANDLE WINAPI HeapCreate(DWORD flOptions, SIZE_T dwInitialSize, SIZE_T dwMaximum
 		return nullptr;
 	}
 
-	mi_heap_t *heap = mi_heap_new();
+	mi_heap_t *heap = wibo::heap::createGuestHeap();
 	if (!heap) {
 		setLastError(ERROR_NOT_ENOUGH_MEMORY);
 		return nullptr;
@@ -211,7 +213,11 @@ LPVOID WINAPI HeapReAlloc(HANDLE hHeap, DWORD dwFlags, LPVOID lpMem, SIZE_T dwBy
 		return lpMem;
 	}
 
-	void *ret = mi_heap_realloc(record->heap, lpMem, requestSize);
+	auto *heap = record->heap;
+	if (!heap && record->isProcessHeap) {
+		heap = wibo::heap::getGuestHeap();
+	}
+	void *ret = mi_heap_realloc(heap, lpMem, requestSize);
 	if (!ret) {
 		setLastError(ERROR_NOT_ENOUGH_MEMORY);
 		return nullptr;

dll/kernel32/internal.h

@@ -157,7 +157,7 @@ struct HeapObject : public ObjectBase {
 	~HeapObject() override;
 
 	[[nodiscard]] inline bool isOwner() const { return pthread_equal(owner, pthread_self()); }
-	[[nodiscard]] inline bool canAccess() const { return (isProcessHeap || isOwner()) && heap != nullptr; }
+	[[nodiscard]] inline bool canAccess() const { return isProcessHeap || (isOwner() && heap != nullptr); }
 };
 
 inline constexpr uintptr_t kPseudoCurrentProcessHandleValue = static_cast<uintptr_t>(-1);

dll/kernel32/memoryapi.cpp

@@ -4,8 +4,8 @@
 #include "context.h"
 #include "errors.h"
 #include "handles.h"
+#include "heap.h"
 #include "internal.h"
-#include "modules.h"
 #include "strutil.h"
 
 #include <cerrno>
@@ -18,7 +18,6 @@
 #include <sys/mman.h>
 #include <unistd.h>
 #include <utility>
-#include <vector>
 
 namespace {
 
@@ -55,32 +54,12 @@ struct ViewInfo {
 	DWORD protect = PAGE_NOACCESS;
 	DWORD allocationProtect = PAGE_NOACCESS;
 	DWORD type = MEM_PRIVATE;
+	bool managed = false;
 };
 
 std::map<uintptr_t, ViewInfo> g_viewInfo;
 std::mutex g_viewInfoMutex;
 
-struct VirtualAllocation {
-	uintptr_t base = 0;
-	size_t size = 0;
-	DWORD allocationProtect = 0;
-	std::vector<DWORD> pageProtect;
-};
-
-std::map<uintptr_t, VirtualAllocation> g_virtualAllocations;
-std::mutex g_virtualAllocMutex;
-
-size_t systemPageSize() {
-	static size_t cached = []() {
-		long detected = sysconf(_SC_PAGESIZE);
-		if (detected <= 0) {
-			return static_cast<size_t>(4096);
-		}
-		return static_cast<size_t>(detected);
-	}();
-	return cached;
-}
-
 uintptr_t alignDown(uintptr_t value, size_t alignment) {
 	const uintptr_t mask = static_cast<uintptr_t>(alignment) - 1;
 	return value & ~mask;
@@ -97,66 +76,6 @@ uintptr_t alignUp(uintptr_t value, size_t alignment) {
 	return (value + mask) & ~mask;
 }
 
-bool addOverflows(uintptr_t base, size_t amount) {
-	return base > std::numeric_limits<uintptr_t>::max() - static_cast<uintptr_t>(amount);
-}
-
-uintptr_t regionEnd(const VirtualAllocation &region) { return region.base + region.size; }
-
-bool rangeOverlapsLocked(uintptr_t base, size_t length) {
-	if (length == 0) {
-		return false;
-	}
-	if (addOverflows(base, length - 1)) {
-		return true;
-	}
-	uintptr_t end = base + length;
-	auto next = g_virtualAllocations.lower_bound(base);
-	if (next != g_virtualAllocations.begin()) {
-		auto prev = std::prev(next);
-		if (regionEnd(prev->second) > base) {
-			return true;
-		}
-	}
-	if (next != g_virtualAllocations.end() && next->second.base < end) {
-		return true;
-	}
-	return false;
-}
-
-std::map<uintptr_t, VirtualAllocation>::iterator findRegionIterator(uintptr_t address) {
-	auto it = g_virtualAllocations.upper_bound(address);
-	if (it == g_virtualAllocations.begin()) {
-		return g_virtualAllocations.end();
-	}
-	--it;
-	if (address >= regionEnd(it->second)) {
-		return g_virtualAllocations.end();
-	}
-	return it;
-}
-
-VirtualAllocation *lookupRegion(uintptr_t address) {
-	auto it = findRegionIterator(address);
-	if (it == g_virtualAllocations.end()) {
-		return nullptr;
-	}
-	return &it->second;
-}
-
-bool rangeWithinRegion(const VirtualAllocation &region, uintptr_t start, size_t length) {
-	if (length == 0) {
-		return start >= region.base && start <= regionEnd(region);
-	}
-	if (start < region.base) {
-		return false;
-	}
-	if (addOverflows(start, length)) {
-		return false;
-	}
-	return (start + length) <= regionEnd(region);
-}
-
 DWORD desiredAccessToProtect(DWORD desiredAccess, DWORD mappingProtect) {
 	DWORD access = desiredAccess;
 	if ((access & FILE_MAP_ALL_ACCESS) == FILE_MAP_ALL_ACCESS) {
@@ -219,93 +138,12 @@ DWORD desiredAccessToProtect(DWORD desiredAccess, DWORD mappingProtect) {
 	return protect;
 }
 
-void markCommitted(VirtualAllocation &region, uintptr_t start, size_t length, DWORD protect) {
-	if (length == 0) {
-		return;
-	}
-	const size_t pageSize = systemPageSize();
-	const size_t firstPage = (start - region.base) / pageSize;
-	const size_t pageCount = length / pageSize;
-	for (size_t i = 0; i < pageCount; ++i) {
-		region.pageProtect[firstPage + i] = protect;
-	}
-}
-
-void markDecommitted(VirtualAllocation &region, uintptr_t start, size_t length) {
-	if (length == 0) {
-		return;
-	}
-	const size_t pageSize = systemPageSize();
-	const size_t firstPage = (start - region.base) / pageSize;
-	const size_t pageCount = length / pageSize;
-	for (size_t i = 0; i < pageCount; ++i) {
-		region.pageProtect[firstPage + i] = 0;
-	}
-}
-
-bool moduleRegionForAddress(uintptr_t pageBase, MEMORY_BASIC_INFORMATION &info) {
-	if (pageBase == 0) {
-		return false;
-	}
-	wibo::ModuleInfo *module = wibo::moduleInfoFromAddress(reinterpret_cast<void *>(pageBase));
-	if (!module || !module->executable) {
-		return false;
-	}
-	const auto &sections = module->executable->sections;
-	if (sections.empty()) {
-		return false;
-	}
-	size_t matchIndex = sections.size();
-	for (size_t i = 0; i < sections.size(); ++i) {
-		const auto &section = sections[i];
-		if (pageBase >= section.base && pageBase < section.base + section.size) {
-			matchIndex = i;
-			break;
-		}
-	}
-	if (matchIndex == sections.size()) {
-		return false;
-	}
-	uintptr_t blockStart = sections[matchIndex].base;
-	uintptr_t blockEnd = sections[matchIndex].base + sections[matchIndex].size;
-	DWORD blockProtect = sections[matchIndex].protect;
-	for (size_t prev = matchIndex; prev > 0;) {
-		--prev;
-		const auto &section = sections[prev];
-		if (section.base + section.size != blockStart) {
-			break;
-		}
-		if (section.protect != blockProtect) {
-			break;
-		}
-		blockStart = section.base;
-	}
-	for (size_t next = matchIndex + 1; next < sections.size(); ++next) {
-		const auto &section = sections[next];
-		if (section.base != blockEnd) {
-			break;
-		}
-		if (section.protect != blockProtect) {
-			break;
-		}
-		blockEnd = section.base + section.size;
-	}
-	info.BaseAddress = reinterpret_cast<void *>(blockStart);
-	info.AllocationBase = module->executable->imageBase;
-	info.AllocationProtect = blockProtect;
-	info.RegionSize = blockEnd > blockStart ? blockEnd - blockStart : 0;
-	info.State = MEM_COMMIT;
-	info.Protect = blockProtect;
-	info.Type = MEM_IMAGE;
-	return true;
-}
-
 bool mappedViewRegionForAddress(uintptr_t request, uintptr_t pageBase, MEMORY_BASIC_INFORMATION &info) {
 	std::lock_guard guard(g_viewInfoMutex);
 	if (g_viewInfo.empty()) {
 		return false;
 	}
-	const size_t pageSize = systemPageSize();
+	const size_t pageSize = wibo::heap::systemPageSize();
 	for (const auto &entry : g_viewInfo) {
 		const ViewInfo &view = entry.second;
 		if (view.viewLength == 0) {
@@ -335,136 +173,12 @@ bool mappedViewRegionForAddress(uintptr_t request, uintptr_t pageBase, MEMORY_BA
 	return false;
 }
 
-bool virtualAllocationRegionForAddress(uintptr_t pageBase, MEMORY_BASIC_INFORMATION &info) {
-	const size_t pageSize = systemPageSize();
-	std::unique_lock lk(g_virtualAllocMutex);
-	VirtualAllocation *region = lookupRegion(pageBase);
-	if (!region) {
-		uintptr_t regionStart = pageBase;
-		uintptr_t regionEnd = regionStart;
-		auto next = g_virtualAllocations.lower_bound(pageBase);
-		if (next != g_virtualAllocations.end()) {
-			regionEnd = next->second.base;
-		} else {
-			regionEnd = kProcessAddressLimit;
-		}
-		if (regionEnd <= regionStart) {
-			regionEnd = regionStart + pageSize;
-		}
-		lk.unlock();
-		info.BaseAddress = reinterpret_cast<void *>(regionStart);
-		info.AllocationBase = nullptr;
-		info.AllocationProtect = 0;
-		info.RegionSize = regionEnd - regionStart;
-		info.State = MEM_FREE;
-		info.Protect = PAGE_NOACCESS;
-		info.Type = 0;
-		return true;
-	}
-	const uintptr_t regionLimit = region->base + region->size;
-	const size_t pageIndex = (pageBase - region->base) / pageSize;
-	if (pageIndex >= region->pageProtect.size()) {
-		return false;
-	}
-	const DWORD pageProtect = region->pageProtect[pageIndex];
-	const bool committed = pageProtect != 0;
-	uintptr_t blockStart = pageBase;
-	uintptr_t blockEnd = pageBase + pageSize;
-	while (blockStart > region->base) {
-		size_t idx = (blockStart - region->base) / pageSize - 1;
-		DWORD protect = region->pageProtect[idx];
-		bool pageCommitted = protect != 0;
-		if (pageCommitted != committed) {
-			break;
-		}
-		if (committed && protect != pageProtect) {
-			break;
-		}
-		blockStart -= pageSize;
-	}
-	while (blockEnd < regionLimit) {
-		size_t idx = (blockEnd - region->base) / pageSize;
-		if (idx >= region->pageProtect.size()) {
-			break;
-		}
-		DWORD protect = region->pageProtect[idx];
-		bool pageCommitted = protect != 0;
-		if (pageCommitted != committed) {
-			break;
-		}
-		if (committed && protect != pageProtect) {
-			break;
-		}
-		blockEnd += pageSize;
-	}
-	uintptr_t allocationBase = region->base;
-	DWORD allocationProtect = region->allocationProtect != 0 ? region->allocationProtect : PAGE_NOACCESS;
-	DWORD finalProtect = committed ? pageProtect : PAGE_NOACCESS;
-	lk.unlock();
-	info.BaseAddress = reinterpret_cast<void *>(blockStart);
-	info.AllocationBase = reinterpret_cast<void *>(allocationBase);
-	info.AllocationProtect = allocationProtect;
-	info.RegionSize = blockEnd - blockStart;
-	info.State = committed ? MEM_COMMIT : MEM_RESERVE;
-	info.Protect = finalProtect;
-	info.Type = MEM_PRIVATE;
-	return true;
-}
-
-void *alignedReserve(size_t length, int prot, int flags) {
-	const size_t granularity = kVirtualAllocationGranularity;
-	const size_t request = length + granularity;
-	void *raw = mmap(nullptr, request, prot, flags, -1, 0);
-	if (raw == MAP_FAILED) {
-		return MAP_FAILED;
-	}
-	uintptr_t rawAddr = reinterpret_cast<uintptr_t>(raw);
-	uintptr_t aligned = alignUp(rawAddr, granularity);
-	size_t front = aligned - rawAddr;
-	size_t back = (rawAddr + request) - (aligned + length);
-	if (front != 0) {
-		if (munmap(raw, front) != 0) {
-			munmap(raw, request);
-			return MAP_FAILED;
-		}
-	}
-	if (back != 0) {
-		if (munmap(reinterpret_cast<void *>(aligned + length), back) != 0) {
-			munmap(reinterpret_cast<void *>(aligned), length);
-			return MAP_FAILED;
-		}
-	}
-	return reinterpret_cast<void *>(aligned);
-}
-
-int translateProtect(DWORD flProtect) {
-	switch (flProtect) {
-	case PAGE_NOACCESS:
-		return PROT_NONE;
-	case PAGE_READONLY:
-		return PROT_READ;
-	case PAGE_READWRITE:
-	case PAGE_WRITECOPY:
-		return PROT_READ | PROT_WRITE;
-	case PAGE_EXECUTE:
-		return PROT_EXEC;
-	case PAGE_EXECUTE_READ:
-		return PROT_READ | PROT_EXEC;
-	case PAGE_EXECUTE_READWRITE:
-	case PAGE_EXECUTE_WRITECOPY:
-		return PROT_READ | PROT_WRITE | PROT_EXEC;
-	default:
-		DEBUG_LOG("Unhandled flProtect: %u, defaulting to RW\n", flProtect);
-		return PROT_READ | PROT_WRITE;
-	}
-}
-
 } // namespace
 
 namespace kernel32 {
 
 HANDLE WINAPI CreateFileMappingA(HANDLE hFile, LPSECURITY_ATTRIBUTES lpFileMappingAttributes, DWORD flProtect,
-								   DWORD dwMaximumSizeHigh, DWORD dwMaximumSizeLow, LPCSTR lpName) {
+								 DWORD dwMaximumSizeHigh, DWORD dwMaximumSizeLow, LPCSTR lpName) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("CreateFileMappingA(%p, %p, %u, %u, %u, %s)\n", hFile, lpFileMappingAttributes, flProtect,
 			  dwMaximumSizeHigh, dwMaximumSizeLow, lpName ? lpName : "(null)");
@@ -515,7 +229,7 @@ HANDLE WINAPI CreateFileMappingA(HANDLE hFile, LPSECURITY_ATTRIBUTES lpFileMappi
 }
 
 HANDLE WINAPI CreateFileMappingW(HANDLE hFile, LPSECURITY_ATTRIBUTES lpFileMappingAttributes, DWORD flProtect,
-								   DWORD dwMaximumSizeHigh, DWORD dwMaximumSizeLow, LPCWSTR lpName) {
+								 DWORD dwMaximumSizeHigh, DWORD dwMaximumSizeLow, LPCWSTR lpName) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("CreateFileMappingW -> ");
 	std::string name = wideStringToString(lpName);
@@ -581,7 +295,7 @@ static LPVOID mapViewOfFileInternal(Pin<MappingObject> mapping, DWORD dwDesiredA
 	}
 
 	int flags = (mapping->anonymous ? MAP_ANONYMOUS : 0) | (wantCopy ? MAP_PRIVATE : MAP_SHARED);
-	const size_t pageSize = systemPageSize();
+	const size_t pageSize = wibo::heap::systemPageSize();
 	off_t alignedOffset = mapping->anonymous ? 0 : static_cast<off_t>(offset & ~static_cast<uint64_t>(pageSize - 1));
 	size_t offsetDelta = static_cast<size_t>(offset - static_cast<uint64_t>(alignedOffset));
 	uint64_t requestedLength = length + offsetDelta;
@@ -598,6 +312,7 @@ static LPVOID mapViewOfFileInternal(Pin<MappingObject> mapping, DWORD dwDesiredA
 	int mmapFd = mapping->anonymous ? -1 : mapping->fd;
 	void *requestedBase = nullptr;
 	int mapFlags = flags;
+	bool reservedMapping = false;
 	if (baseAddress) {
 		uintptr_t baseAddr = reinterpret_cast<uintptr_t>(baseAddress);
 		if (baseAddr == 0 || (baseAddr % kVirtualAllocationGranularity) != 0) {
@@ -619,6 +334,16 @@ static LPVOID mapViewOfFileInternal(Pin<MappingObject> mapping, DWORD dwDesiredA
 #else
 		mapFlags |= MAP_FIXED;
 #endif
+	} else {
+		void *candidate = nullptr;
+		wibo::heap::VmStatus reserveStatus = wibo::heap::reserveViewRange(mapLength, 0, 0, &candidate);
+		if (reserveStatus != wibo::heap::VmStatus::Success) {
+			setLastError(wibo::heap::win32ErrorFromVmStatus(reserveStatus));
+			return nullptr;
+		}
+		reservedMapping = true;
+		requestedBase = candidate;
+		mapFlags |= MAP_FIXED;
 	}
 
 	errno = 0;
@@ -630,12 +355,18 @@ static LPVOID mapViewOfFileInternal(Pin<MappingObject> mapping, DWORD dwDesiredA
 		} else {
 			setLastError(wibo::winErrorFromErrno(err));
 		}
+		if (reservedMapping) {
+			wibo::heap::releaseViewRange(requestedBase);
+		}
 		return nullptr;
 	}
 	void *viewPtr = static_cast<uint8_t *>(mapBase) + offsetDelta;
 	if (baseAddress && viewPtr != baseAddress) {
 		munmap(mapBase, mapLength);
 		setLastError(ERROR_INVALID_ADDRESS);
+		if (reservedMapping) {
+			wibo::heap::releaseViewRange(requestedBase);
+		}
 		return nullptr;
 	}
 	uintptr_t viewLength = static_cast<uintptr_t>(length);
@@ -653,6 +384,10 @@ static LPVOID mapViewOfFileInternal(Pin<MappingObject> mapping, DWORD dwDesiredA
 	view.protect = desiredAccessToProtect(dwDesiredAccess, protect);
 	view.allocationProtect = protect;
 	view.type = MEM_MAPPED;
+	view.managed = reservedMapping;
+	if (reservedMapping) {
+		wibo::heap::registerViewRange(mapBase, mapLength, protect, view.protect);
+	}
 	{
 		std::lock_guard guard(g_viewInfoMutex);
 		g_viewInfo.emplace(view.viewBase, std::move(view));
@@ -661,7 +396,7 @@ static LPVOID mapViewOfFileInternal(Pin<MappingObject> mapping, DWORD dwDesiredA
 }
 
 LPVOID WINAPI MapViewOfFile(HANDLE hFileMappingObject, DWORD dwDesiredAccess, DWORD dwFileOffsetHigh,
-							  DWORD dwFileOffsetLow, SIZE_T dwNumberOfBytesToMap) {
+							DWORD dwFileOffsetLow, SIZE_T dwNumberOfBytesToMap) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("MapViewOfFile(%p, 0x%x, %u, %u, %zu)\n", hFileMappingObject, dwDesiredAccess, dwFileOffsetHigh,
 			  dwFileOffsetLow, dwNumberOfBytesToMap);
@@ -676,7 +411,7 @@ LPVOID WINAPI MapViewOfFile(HANDLE hFileMappingObject, DWORD dwDesiredAccess, DW
 }
 
 LPVOID WINAPI MapViewOfFileEx(HANDLE hFileMappingObject, DWORD dwDesiredAccess, DWORD dwFileOffsetHigh,
-								DWORD dwFileOffsetLow, SIZE_T dwNumberOfBytesToMap, LPVOID lpBaseAddress) {
+							  DWORD dwFileOffsetLow, SIZE_T dwNumberOfBytesToMap, LPVOID lpBaseAddress) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("MapViewOfFileEx(%p, 0x%x, %u, %u, %zu, %p)\n", hFileMappingObject, dwDesiredAccess, dwFileOffsetHigh,
 			  dwFileOffsetLow, dwNumberOfBytesToMap, lpBaseAddress);
@@ -701,11 +436,15 @@ BOOL WINAPI UnmapViewOfFile(LPCVOID lpBaseAddress) {
 	}
 	void *base = reinterpret_cast<void *>(it->second.allocationBase);
 	size_t length = it->second.allocationLength;
+	bool managed = it->second.managed;
 	g_viewInfo.erase(it);
 	lk.unlock();
 	if (length != 0) {
 		munmap(base, length);
 	}
+	if (managed) {
+		wibo::heap::releaseViewRange(base);
+	}
 	return TRUE;
 }
 
@@ -755,7 +494,7 @@ BOOL WINAPI FlushViewOfFile(LPCVOID lpBaseAddress, SIZE_T dwNumberOfBytesToFlush
 
 	uintptr_t flushStart = address;
 	uintptr_t flushEnd = flushStart + bytesToFlush;
-	const size_t pageSize = systemPageSize();
+	const size_t pageSize = wibo::heap::systemPageSize();
 	uintptr_t alignedStart = alignDown(flushStart, pageSize);
 	uintptr_t alignedEnd = alignUp(flushEnd, pageSize);
 	if (alignedEnd == std::numeric_limits<uintptr_t>::max()) {
@@ -788,336 +527,42 @@ LPVOID WINAPI VirtualAlloc(LPVOID lpAddress, SIZE_T dwSize, DWORD flAllocationTy
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("VirtualAlloc(%p, %zu, %u, %u)\n", lpAddress, dwSize, flAllocationType, flProtect);
 
-	if (dwSize == 0) {
+	void *base = lpAddress;
-		setLastError(ERROR_INVALID_PARAMETER);
+	std::size_t size = static_cast<std::size_t>(dwSize);
+	wibo::heap::VmStatus status = wibo::heap::virtualAlloc(&base, &size, flAllocationType, flProtect);
+	if (status != wibo::heap::VmStatus::Success) {
+		DWORD err = wibo::heap::win32ErrorFromVmStatus(status);
+		DEBUG_LOG("-> failed (status=%u, err=%u)\n", static_cast<unsigned>(status), err);
+		setLastError(err);
 		return nullptr;
 	}
-
+	return base;
-	DWORD unsupportedFlags = flAllocationType & (MEM_WRITE_WATCH | MEM_PHYSICAL | MEM_LARGE_PAGES | MEM_RESET_UNDO);
-	if (unsupportedFlags != 0) {
-		DEBUG_LOG("VirtualAlloc unsupported flags: 0x%x\n", unsupportedFlags);
-		setLastError(ERROR_NOT_SUPPORTED);
-		return nullptr;
-	}
-
-	bool reserve = (flAllocationType & MEM_RESERVE) != 0;
-	bool commit = (flAllocationType & MEM_COMMIT) != 0;
-	bool reset = (flAllocationType & MEM_RESET) != 0;
-
-	if (!reserve && commit && lpAddress == nullptr) {
-		reserve = true;
-	}
-
-	if (reset) {
-		if (reserve || commit) {
-			setLastError(ERROR_INVALID_PARAMETER);
-			return nullptr;
-		}
-		if (!lpAddress) {
-			setLastError(ERROR_INVALID_ADDRESS);
-			return nullptr;
-		}
-		const size_t pageSize = systemPageSize();
-		uintptr_t request = reinterpret_cast<uintptr_t>(lpAddress);
-		if (addOverflows(request, static_cast<size_t>(dwSize))) {
-			setLastError(ERROR_INVALID_PARAMETER);
-			return nullptr;
-		}
-		uintptr_t start = alignDown(request, pageSize);
-		uintptr_t end = alignUp(request + static_cast<uintptr_t>(dwSize), pageSize);
-		size_t length = static_cast<size_t>(end - start);
-		std::unique_lock lk(g_virtualAllocMutex);
-		VirtualAllocation *region = lookupRegion(start);
-		if (!region || !rangeWithinRegion(*region, start, length)) {
-			setLastError(ERROR_INVALID_ADDRESS);
-			return nullptr;
-		}
-#ifdef MADV_FREE
-		int advice = MADV_FREE;
-#else
-		int advice = MADV_DONTNEED;
-#endif
-		if (madvise(reinterpret_cast<void *>(start), length, advice) != 0) {
-			setLastErrorFromErrno();
-			return nullptr;
-		}
-		return reinterpret_cast<LPVOID>(start);
-	}
-
-	if (!reserve && !commit) {
-		setLastError(ERROR_INVALID_PARAMETER);
-		return nullptr;
-	}
-
-	const size_t pageSize = systemPageSize();
-	std::unique_lock lk(g_virtualAllocMutex);
-
-	if (reserve) {
-		uintptr_t base = 0;
-		size_t length = 0;
-		if (lpAddress) {
-			uintptr_t request = reinterpret_cast<uintptr_t>(lpAddress);
-			base = alignDown(request, kVirtualAllocationGranularity);
-			size_t offset = static_cast<size_t>(request - base);
-			if (addOverflows(offset, static_cast<size_t>(dwSize))) {
-				setLastError(ERROR_INVALID_PARAMETER);
-				return nullptr;
-			}
-			size_t span = static_cast<size_t>(dwSize) + offset;
-			uintptr_t alignedSpan = alignUp(span, pageSize);
-			if (alignedSpan == std::numeric_limits<uintptr_t>::max()) {
-				setLastError(ERROR_INVALID_PARAMETER);
-				return nullptr;
-			}
-			length = static_cast<size_t>(alignedSpan);
-			if (length == 0 || rangeOverlapsLocked(base, length)) {
-				setLastError(ERROR_INVALID_ADDRESS);
-				return nullptr;
-			}
-		} else {
-			uintptr_t aligned = alignUp(static_cast<uintptr_t>(dwSize), pageSize);
-			if (aligned == std::numeric_limits<uintptr_t>::max() || aligned == 0) {
-				setLastError(ERROR_INVALID_PARAMETER);
-				return nullptr;
-			}
-			length = static_cast<size_t>(aligned);
-		}
-		const int prot = commit ? translateProtect(flProtect) : PROT_NONE;
-		int flags = MAP_PRIVATE | MAP_ANONYMOUS;
-		if (!commit) {
-			flags |= MAP_NORESERVE;
-		}
-		void *result = MAP_FAILED;
-		if (lpAddress) {
-#ifdef MAP_FIXED_NOREPLACE
-			flags |= MAP_FIXED_NOREPLACE;
-#else
-			flags |= MAP_FIXED;
-#endif
-			result = mmap(reinterpret_cast<void *>(base), length, prot, flags, -1, 0);
-		} else {
-			result = alignedReserve(length, prot, flags);
-		}
-		if (result == MAP_FAILED) {
-			setLastErrorFromErrno();
-			return nullptr;
-		}
-		if (reinterpret_cast<uintptr_t>(result) >= 0x80000000) {
-			munmap(result, length);
-			setLastError(ERROR_NOT_ENOUGH_MEMORY);
-			return nullptr;
-		}
-		uintptr_t actualBase = reinterpret_cast<uintptr_t>(result);
-		VirtualAllocation allocation{};
-		allocation.base = actualBase;
-		allocation.size = length;
-		allocation.allocationProtect = flProtect;
-		allocation.pageProtect.assign(length / pageSize, commit ? flProtect : 0);
-		g_virtualAllocations[actualBase] = std::move(allocation);
-		return result;
-	}
-
-	uintptr_t request = reinterpret_cast<uintptr_t>(lpAddress);
-	if (addOverflows(request, static_cast<size_t>(dwSize))) {
-		setLastError(ERROR_INVALID_PARAMETER);
-		return nullptr;
-	}
-	uintptr_t start = alignDown(request, pageSize);
-	uintptr_t end = alignUp(request + static_cast<uintptr_t>(dwSize), pageSize);
-	size_t length = static_cast<size_t>(end - start);
-	if (length == 0) {
-		setLastError(ERROR_INVALID_PARAMETER);
-		return nullptr;
-	}
-	VirtualAllocation *region = lookupRegion(start);
-	if (!region || !rangeWithinRegion(*region, start, length)) {
-		setLastError(ERROR_INVALID_ADDRESS);
-		return nullptr;
-	}
-	const size_t pageCount = length / pageSize;
-	std::vector<std::pair<uintptr_t, size_t>> committedRuns;
-	committedRuns.reserve(pageCount);
-	for (size_t i = 0; i < pageCount; ++i) {
-		size_t pageIndex = ((start - region->base) / pageSize) + i;
-		if (pageIndex >= region->pageProtect.size()) {
-			setLastError(ERROR_INVALID_ADDRESS);
-			return nullptr;
-		}
-		if (region->pageProtect[pageIndex] != 0) {
-			continue;
-		}
-		uintptr_t runBase = start + i * pageSize;
-		size_t runLength = pageSize;
-		while (i + 1 < pageCount) {
-			size_t nextIndex = ((start - region->base) / pageSize) + i + 1;
-			if (region->pageProtect[nextIndex] != 0) {
-				break;
-			}
-			++i;
-			runLength += pageSize;
-		}
-		committedRuns.emplace_back(runBase, runLength);
-	}
-	for (const auto &run : committedRuns) {
-		void *result = mmap(reinterpret_cast<void *>(run.first), run.second, translateProtect(flProtect),
-							MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
-		if (result == MAP_FAILED) {
-			setLastErrorFromErrno();
-			return nullptr;
-		}
-		markCommitted(*region, run.first, run.second, flProtect);
-	}
-	DEBUG_LOG("VirtualAlloc commit success -> %p\n", reinterpret_cast<void *>(start));
-	return reinterpret_cast<LPVOID>(start);
 }
 
 BOOL WINAPI VirtualFree(LPVOID lpAddress, SIZE_T dwSize, DWORD dwFreeType) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("VirtualFree(%p, %zu, %u)\n", lpAddress, dwSize, dwFreeType);
-	if (!lpAddress) {
+	wibo::heap::VmStatus status = wibo::heap::virtualFree(lpAddress, static_cast<std::size_t>(dwSize), dwFreeType);
-		setLastError(ERROR_INVALID_ADDRESS);
+	if (status != wibo::heap::VmStatus::Success) {
+		DWORD err = wibo::heap::win32ErrorFromVmStatus(status);
+		DEBUG_LOG("-> failed (status=%u, err=%u)\n", static_cast<unsigned>(status), err);
+		setLastError(err);
 		return FALSE;
 	}
-
-	if ((dwFreeType & (MEM_COALESCE_PLACEHOLDERS | MEM_PRESERVE_PLACEHOLDER)) != 0) {
-		setLastError(ERROR_NOT_SUPPORTED);
-		return FALSE;
-	}
-
-	const bool release = (dwFreeType & MEM_RELEASE) != 0;
-	const bool decommit = (dwFreeType & MEM_DECOMMIT) != 0;
-	if (release == decommit) {
-		setLastError(ERROR_INVALID_PARAMETER);
-		return FALSE;
-	}
-
-	const size_t pageSize = systemPageSize();
-	std::unique_lock lk(g_virtualAllocMutex);
-
-	if (release) {
-		uintptr_t base = reinterpret_cast<uintptr_t>(lpAddress);
-		auto exact = g_virtualAllocations.find(base);
-		if (exact == g_virtualAllocations.end()) {
-			auto containing = findRegionIterator(base);
-			if (dwSize != 0 && containing != g_virtualAllocations.end()) {
-				setLastError(ERROR_INVALID_PARAMETER);
-			} else {
-				setLastError(ERROR_INVALID_ADDRESS);
-			}
-			return FALSE;
-		}
-		if (dwSize != 0) {
-			setLastError(ERROR_INVALID_PARAMETER);
-			return FALSE;
-		}
-		size_t length = exact->second.size;
-		g_virtualAllocations.erase(exact);
-		lk.unlock();
-		if (munmap(lpAddress, length) != 0) {
-			setLastErrorFromErrno();
-			return FALSE;
-		}
-		return TRUE;
-	}
-
-	uintptr_t request = reinterpret_cast<uintptr_t>(lpAddress);
-	auto regionIt = findRegionIterator(request);
-	if (regionIt == g_virtualAllocations.end()) {
-		setLastError(ERROR_INVALID_ADDRESS);
-		return FALSE;
-	}
-	VirtualAllocation &region = regionIt->second;
-	uintptr_t start = alignDown(request, pageSize);
-	uintptr_t end = 0;
-	if (dwSize == 0) {
-		if (request != region.base) {
-			setLastError(ERROR_INVALID_PARAMETER);
-			return FALSE;
-		}
-		start = region.base;
-		end = region.base + region.size;
-	} else {
-		if (addOverflows(request, static_cast<size_t>(dwSize))) {
-			setLastError(ERROR_INVALID_PARAMETER);
-			return FALSE;
-		}
-		end = alignUp(request + static_cast<uintptr_t>(dwSize), pageSize);
-	}
-	if (end <= start) {
-		setLastError(ERROR_INVALID_PARAMETER);
-		return FALSE;
-	}
-	size_t length = static_cast<size_t>(end - start);
-	if (!rangeWithinRegion(region, start, length)) {
-		setLastError(ERROR_INVALID_ADDRESS);
-		return FALSE;
-	}
-	void *result = mmap(reinterpret_cast<void *>(start), length, PROT_NONE,
-						MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED | MAP_NORESERVE, -1, 0);
-	if (result == MAP_FAILED) {
-		setLastErrorFromErrno();
-		return FALSE;
-	}
-	markDecommitted(region, start, length);
 	return TRUE;
 }
 
 BOOL WINAPI VirtualProtect(LPVOID lpAddress, SIZE_T dwSize, DWORD flNewProtect, PDWORD lpflOldProtect) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("VirtualProtect(%p, %zu, %u)\n", lpAddress, dwSize, flNewProtect);
-	if (!lpAddress || dwSize == 0) {
+	wibo::heap::VmStatus status =
-		setLastError(ERROR_INVALID_PARAMETER);
+		wibo::heap::virtualProtect(lpAddress, static_cast<std::size_t>(dwSize), flNewProtect, lpflOldProtect);
+	if (status != wibo::heap::VmStatus::Success) {
+		DWORD err = wibo::heap::win32ErrorFromVmStatus(status);
+		DEBUG_LOG("-> failed (status=%u, err=%u)\n", static_cast<unsigned>(status), err);
+		setLastError(err);
 		return FALSE;
 	}
-
-	const size_t pageSize = systemPageSize();
-	uintptr_t request = reinterpret_cast<uintptr_t>(lpAddress);
-	uintptr_t start = alignDown(request, pageSize);
-	uintptr_t end = alignUp(request + static_cast<uintptr_t>(dwSize), pageSize);
-	if (end <= start) {
-		setLastError(ERROR_INVALID_PARAMETER);
-		return FALSE;
-	}
-
-	std::unique_lock lk(g_virtualAllocMutex);
-	VirtualAllocation *region = lookupRegion(start);
-	if (!region || !rangeWithinRegion(*region, start, static_cast<size_t>(end - start))) {
-		setLastError(ERROR_INVALID_ADDRESS);
-		return FALSE;
-	}
-
-	const size_t firstPage = (start - region->base) / pageSize;
-	const size_t pageCount = (end - start) / pageSize;
-	if (pageCount == 0) {
-		setLastError(ERROR_INVALID_PARAMETER);
-		return FALSE;
-	}
-
-	DWORD previousProtect = region->pageProtect[firstPage];
-	if (previousProtect == 0) {
-		setLastError(ERROR_NOACCESS);
-		return FALSE;
-	}
-	for (size_t i = 0; i < pageCount; ++i) {
-		if (region->pageProtect[firstPage + i] == 0) {
-			setLastError(ERROR_NOACCESS);
-			return FALSE;
-		}
-	}
-
-	int prot = translateProtect(flNewProtect);
-	if (mprotect(reinterpret_cast<void *>(start), end - start, prot) != 0) {
-		setLastErrorFromErrno();
-		return FALSE;
-	}
-	for (size_t i = 0; i < pageCount; ++i) {
-		region->pageProtect[firstPage + i] = flNewProtect;
-	}
-	lk.unlock();
-
-	if (lpflOldProtect) {
-		*lpflOldProtect = previousProtect;
-	}
 	return TRUE;
 }
 
@@ -1131,7 +576,7 @@ SIZE_T WINAPI VirtualQuery(LPCVOID lpAddress, PMEMORY_BASIC_INFORMATION lpBuffer
 	}
 
 	std::memset(lpBuffer, 0, sizeof(MEMORY_BASIC_INFORMATION));
-	const size_t pageSize = systemPageSize();
+	const size_t pageSize = wibo::heap::systemPageSize();
 	uintptr_t request = lpAddress ? reinterpret_cast<uintptr_t>(lpAddress) : 0;
 	uintptr_t pageBase = alignDown(request, pageSize);
 	if (pageBase >= kProcessAddressLimit) {
@@ -1141,26 +586,25 @@ SIZE_T WINAPI VirtualQuery(LPCVOID lpAddress, PMEMORY_BASIC_INFORMATION lpBuffer
 	}
 
 	MEMORY_BASIC_INFORMATION info{};
-	if (moduleRegionForAddress(pageBase, info)) {
-		*lpBuffer = info;
-		return sizeof(MEMORY_BASIC_INFORMATION);
-	}
 	if (mappedViewRegionForAddress(request, pageBase, info)) {
 		*lpBuffer = info;
 		return sizeof(MEMORY_BASIC_INFORMATION);
 	}
-	if (virtualAllocationRegionForAddress(pageBase, info)) {
+
+	wibo::heap::VmStatus status = wibo::heap::virtualQuery(lpAddress, &info);
+	if (status == wibo::heap::VmStatus::Success) {
 		*lpBuffer = info;
 		return sizeof(MEMORY_BASIC_INFORMATION);
 	}
 
-	setLastError(ERROR_INVALID_ADDRESS);
+	DEBUG_LOG("VirtualQuery fallback failed status=%u\n", static_cast<unsigned>(status));
-	DEBUG_LOG("-> ERROR_INVALID_ADDRESS\n");
+	setLastError(wibo::heap::win32ErrorFromVmStatus(status));
+	DEBUG_LOG("-> VirtualQuery failed (status=%u)\n", static_cast<unsigned>(status));
 	return 0;
 }
 
 BOOL WINAPI GetProcessWorkingSetSize(HANDLE hProcess, PSIZE_T lpMinimumWorkingSetSize,
-									   PSIZE_T lpMaximumWorkingSetSize) {
+									 PSIZE_T lpMaximumWorkingSetSize) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("GetProcessWorkingSetSize(%p, %p, %p)\n", hProcess, lpMinimumWorkingSetSize, lpMaximumWorkingSetSize);
 	(void)hProcess;
@@ -1173,8 +617,7 @@ BOOL WINAPI GetProcessWorkingSetSize(HANDLE hProcess, PSIZE_T lpMinimumWorkingSe
 	return TRUE;
 }
 
-BOOL WINAPI SetProcessWorkingSetSize(HANDLE hProcess, SIZE_T dwMinimumWorkingSetSize,
+BOOL WINAPI SetProcessWorkingSetSize(HANDLE hProcess, SIZE_T dwMinimumWorkingSetSize, SIZE_T dwMaximumWorkingSetSize) {
-									   SIZE_T dwMaximumWorkingSetSize) {
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("SetProcessWorkingSetSize(%p, %zu, %zu)\n", hProcess, dwMinimumWorkingSetSize, dwMaximumWorkingSetSize);
 	(void)hProcess;

dll/kernel32/memoryapi.h

@@ -3,18 +3,6 @@
 #include "types.h"
 #include "minwinbase.h"
 
-struct MEMORY_BASIC_INFORMATION {
-	PVOID BaseAddress;
-	PVOID AllocationBase;
-	DWORD AllocationProtect;
-	SIZE_T RegionSize;
-	DWORD State;
-	DWORD Protect;
-	DWORD Type;
-};
-
-using PMEMORY_BASIC_INFORMATION = MEMORY_BASIC_INFORMATION *;
-
 namespace kernel32 {
 
 HANDLE WINAPI CreateFileMappingA(HANDLE hFile, LPSECURITY_ATTRIBUTES lpFileMappingAttributes, DWORD flProtect,

dll/kernel32/processenv.cpp

@@ -3,6 +3,7 @@
 #include "context.h"
 #include "errors.h"
 #include "files.h"
+#include "heap.h"
 #include "internal.h"
 #include "strutil.h"
 
@@ -78,7 +79,7 @@ LPCH WINAPI GetEnvironmentStrings() {
 	}
 	bufSize++;
 
-	char *buffer = static_cast<char *>(mi_malloc(bufSize));
+	char *buffer = static_cast<char *>(wibo::heap::guestMalloc(bufSize));
 	if (!buffer) {
 		setLastError(ERROR_NOT_ENOUGH_MEMORY);
 		return nullptr;
@@ -111,7 +112,7 @@ LPWCH WINAPI GetEnvironmentStringsW() {
 	}
 	bufSizeW++;
 
-	uint16_t *buffer = static_cast<uint16_t *>(mi_malloc(bufSizeW * sizeof(uint16_t)));
+	uint16_t *buffer = static_cast<uint16_t *>(wibo::heap::guestMalloc(bufSizeW * sizeof(uint16_t)));
 	if (!buffer) {
 		setLastError(ERROR_NOT_ENOUGH_MEMORY);
 		return nullptr;

dll/kernel32/processthreadsapi.cpp

@@ -148,7 +148,6 @@ void *threadTrampoline(void *param) {
 	DEBUG_LOG("Calling thread entry %p with userData %p\n", data.entry, data.userData);
 	DWORD result = 0;
 	if (data.entry) {
-		GUEST_CONTEXT_GUARD(threadTib);
 		result = call_LPTHREAD_START_ROUTINE(data.entry, data.userData);
 	}
 	DEBUG_LOG("Thread exiting with code %u\n", result);

dll/kernel32/winbase.cpp

@@ -4,6 +4,7 @@
 #include "context.h"
 #include "errors.h"
 #include "files.h"
+#include "heap.h"
 #include "internal.h"
 #include "modules.h"
 #include "strutil.h"
@@ -169,7 +170,7 @@ void *doAlloc(UINT dwBytes, bool zero) {
 	if (dwBytes == 0) {
 		dwBytes = 1;
 	}
-	void *ret = mi_malloc_aligned(dwBytes, 8);
+	void *ret = mi_heap_malloc_aligned(wibo::heap::getGuestHeap(), dwBytes, 8);
 	if (ret && zero) {
 		std::memset(ret, 0, mi_usable_size(ret));
 	}
@@ -181,7 +182,7 @@ void *doRealloc(void *mem, UINT dwBytes, bool zero) {
 		dwBytes = 1;
 	}
 	size_t oldSize = mi_usable_size(mem);
-	void *ret = mi_realloc_aligned(mem, dwBytes, 8);
+	void *ret = mi_heap_realloc_aligned(wibo::heap::getGuestHeap(), mem, dwBytes, 8);
 	size_t newSize = mi_usable_size(ret);
 	if (ret && zero && newSize > oldSize) {
 		std::memset(static_cast<char *>(ret) + oldSize, 0, newSize - oldSize);

dll/msvcrt.cpp

@@ -3,6 +3,7 @@
 #include "common.h"
 #include "context.h"
 #include "files.h"
+#include "heap.h"
 #include "kernel32/internal.h"
 #include "modules.h"
 #include "msvcrt_trampolines.h"
@@ -1382,7 +1383,7 @@ namespace msvcrt {
 			std::strcpy(absPath, winPath.c_str());
 			return absPath;
 		}
-		char *result = static_cast<char *>(std::malloc(winPath.size() + 1));
+		char *result = static_cast<char *>(wibo::heap::guestMalloc(winPath.size() + 1));
 		if (!result) {
 			errno = ENOMEM;
 			return nullptr;
@@ -1512,7 +1513,7 @@ namespace msvcrt {
 		}
 
 		SIZE_T value_len = match->length;
-		auto *copy = static_cast<uint16_t *>(malloc((value_len + 1) * sizeof(uint16_t)));
+		auto *copy = static_cast<uint16_t *>(wibo::heap::guestMalloc((value_len + 1) * sizeof(uint16_t)));
 		if (!copy) {
 			DEBUG_LOG("_wdupenv_s: allocation failed\n");
 			errno = ENOMEM;
@@ -1686,7 +1687,7 @@ namespace msvcrt {
 		}
 
 		SIZE_T length = ::strlen(strSource);
-		auto *copy = static_cast<char *>(std::malloc(length + 1));
+		auto *copy = static_cast<char *>(wibo::heap::guestMalloc(length + 1));
 		if (!copy) {
 			return nullptr;
 		}
@@ -1704,25 +1705,25 @@ namespace msvcrt {
 	void* CDECL malloc(SIZE_T size){
 		HOST_CONTEXT_GUARD();
 		VERBOSE_LOG("malloc(%zu)\n", size);
-		return std::malloc(size);
+		return wibo::heap::guestMalloc(size);
 	}
 
 	void* CDECL calloc(SIZE_T count, SIZE_T size){
 		HOST_CONTEXT_GUARD();
 		VERBOSE_LOG("calloc(%zu, %zu)\n", count, size);
-		return std::calloc(count, size);
+		return wibo::heap::guestCalloc(count, size);
 	}
 
 	void* CDECL realloc(void *ptr, SIZE_T size) {
 		HOST_CONTEXT_GUARD();
 		VERBOSE_LOG("realloc(%p, %zu)\n", ptr, size);
-		return std::realloc(ptr, size);
+		return wibo::heap::guestRealloc(ptr, size);
 	}
 
 	void* CDECL _malloc_crt(SIZE_T size) {
 		HOST_CONTEXT_GUARD();
 		VERBOSE_LOG("_malloc_crt(%zu)\n", size);
-		return std::malloc(size);
+		return wibo::heap::guestMalloc(size);
 	}
 
 	void CDECL _lock(int locknum) {
@@ -2479,7 +2480,7 @@ namespace msvcrt {
 		if(!strSource) return nullptr;
 		SIZE_T strLen = wstrlen(strSource);
 
-		auto *dup = static_cast<uint16_t *>(malloc((strLen + 1) * sizeof(uint16_t)));
+		auto *dup = static_cast<uint16_t *>(wibo::heap::guestMalloc((strLen + 1) * sizeof(uint16_t)));
 		if(!dup) return nullptr;
 
 		for(SIZE_T i = 0; i <= strLen; i++){
@@ -3000,7 +3001,7 @@ namespace msvcrt {
 	        return absPath;
 	    } else {
 	        // Windows behavior: if absPath == NULL, allocate new
-	        auto *newBuf = new uint16_t[wResolved.size() + 1];
+	        auto *newBuf = static_cast<uint16_t*>(wibo::heap::guestMalloc((wResolved.size() + 1) * sizeof(uint16_t)));
 	        std::copy(wResolved.begin(), wResolved.end(), newBuf);
 	        newBuf[wResolved.size()] = 0;
 

dll/ntdll.cpp

@@ -5,6 +5,7 @@
 #include "errors.h"
 #include "files.h"
 #include "handles.h"
+#include "heap.h"
 #include "kernel32/internal.h"
 #include "kernel32/processthreadsapi.h"
 #include "modules.h"
@@ -14,7 +15,6 @@
 
 #include <cerrno>
 #include <cstring>
-#include <sys/mman.h>
 #include <sys/stat.h>
 #include <unistd.h>
 
@@ -267,35 +267,23 @@ NTSTATUS WINAPI NtAllocateVirtualMemory(HANDLE ProcessHandle, PVOID *BaseAddress
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("NtAllocateVirtualMemory(%p, %p, %lu, %p, %lu, %lu) ", ProcessHandle, BaseAddress, ZeroBits, RegionSize,
 			  AllocationType, Protect);
-	assert(ProcessHandle == (HANDLE)-1);
+	if (ProcessHandle != (HANDLE)-1) {
-	assert(ZeroBits == 0);
+		DEBUG_LOG("-> 0x%x\n", STATUS_INVALID_HANDLE);
-
+		return STATUS_INVALID_HANDLE;
-	int prot = 0;
+	}
-	if (Protect & PAGE_NOACCESS)
+	if (ZeroBits != 0 || BaseAddress == nullptr || RegionSize == nullptr) {
-		prot |= PROT_NONE;
+		DEBUG_LOG("-> 0x%x\n", STATUS_INVALID_PARAMETER);
-	if (Protect & PAGE_READONLY)
+		return STATUS_INVALID_PARAMETER;
-		prot |= PROT_READ;
+	}
-	if (Protect & PAGE_READWRITE)
+
-		prot |= PROT_READ | PROT_WRITE;
+	wibo::heap::VmStatus vmStatus =
-	if (Protect & PAGE_WRITECOPY)
+		wibo::heap::virtualAlloc(reinterpret_cast<void **>(BaseAddress), reinterpret_cast<std::size_t *>(RegionSize),
-		prot |= PROT_READ | PROT_WRITE;
+								 static_cast<DWORD>(AllocationType), static_cast<DWORD>(Protect));
-	if (Protect & PAGE_EXECUTE)
+	if (vmStatus != wibo::heap::VmStatus::Success) {
-		prot |= PROT_EXEC;
+		NTSTATUS status = wibo::heap::ntStatusFromVmStatus(vmStatus);
-	if (Protect & PAGE_EXECUTE_READ)
+		DEBUG_LOG("-> 0x%x\n", status);
-		prot |= PROT_EXEC | PROT_READ;
+		return status;
-	if (Protect & PAGE_EXECUTE_READWRITE)
-		prot |= PROT_EXEC | PROT_READ | PROT_WRITE;
-	assert(!(Protect & PAGE_EXECUTE_WRITECOPY));
-	assert(!(Protect & PAGE_GUARD));
-	assert(!(Protect & PAGE_NOCACHE));
-	assert(!(Protect & PAGE_WRITECOMBINE));
-
-	void *addr = mmap(*BaseAddress, *RegionSize, prot, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-	if (addr == MAP_FAILED) {
-		perror("mmap");
-		return STATUS_NOT_SUPPORTED;
 	}
-	*BaseAddress = addr;
 
 	DEBUG_LOG("-> 0x%x\n", STATUS_SUCCESS);
 	return STATUS_SUCCESS;
@@ -306,38 +294,25 @@ NTSTATUS WINAPI NtProtectVirtualMemory(HANDLE ProcessHandle, PVOID *BaseAddress,
 	HOST_CONTEXT_GUARD();
 	DEBUG_LOG("NtProtectVirtualMemory(%p, %p, %p, %lu, %p) ", ProcessHandle, BaseAddress, NumberOfBytesToProtect,
 			  NewAccessProtection, OldAccessProtection);
-	assert(ProcessHandle == (HANDLE)-1);
+	if (ProcessHandle != (HANDLE)-1) {
-	assert(NumberOfBytesToProtect != nullptr);
+		DEBUG_LOG("-> 0x%x\n", STATUS_INVALID_HANDLE);
-
+		return STATUS_INVALID_HANDLE;
-	int prot = 0;
+	}
-	if (NewAccessProtection & PAGE_NOACCESS)
+	if (BaseAddress == nullptr || NumberOfBytesToProtect == nullptr) {
-		prot |= PROT_NONE;
+		DEBUG_LOG("-> 0x%x\n", STATUS_INVALID_PARAMETER);
-	if (NewAccessProtection & PAGE_READONLY)
+		return STATUS_INVALID_PARAMETER;
-		prot |= PROT_READ;
-	if (NewAccessProtection & PAGE_READWRITE)
-		prot |= PROT_READ | PROT_WRITE;
-	if (NewAccessProtection & PAGE_WRITECOPY)
-		prot |= PROT_READ | PROT_WRITE;
-	if (NewAccessProtection & PAGE_EXECUTE)
-		prot |= PROT_EXEC;
-	if (NewAccessProtection & PAGE_EXECUTE_READ)
-		prot |= PROT_EXEC | PROT_READ;
-	if (NewAccessProtection & PAGE_EXECUTE_READWRITE)
-		prot |= PROT_EXEC | PROT_READ | PROT_WRITE;
-	assert(!(NewAccessProtection & PAGE_EXECUTE_WRITECOPY));
-	assert(!(NewAccessProtection & PAGE_GUARD));
-	assert(!(NewAccessProtection & PAGE_NOCACHE));
-	assert(!(NewAccessProtection & PAGE_WRITECOMBINE));
-
-	int ret = mprotect(*BaseAddress, *NumberOfBytesToProtect, prot);
-	if (ret != 0) {
-		perror("mprotect");
-		return STATUS_NOT_SUPPORTED;
 	}
 
-	if (OldAccessProtection) {
+	void *base = *BaseAddress;
-		*OldAccessProtection = 0; // stub
+	std::size_t length = static_cast<std::size_t>(*NumberOfBytesToProtect);
+	wibo::heap::VmStatus vmStatus =
+		wibo::heap::virtualProtect(base, length, static_cast<DWORD>(NewAccessProtection), OldAccessProtection);
+	if (vmStatus != wibo::heap::VmStatus::Success) {
+		NTSTATUS status = wibo::heap::ntStatusFromVmStatus(vmStatus);
+		DEBUG_LOG("-> 0x%x\n", status);
+		return status;
 	}
+
 	DEBUG_LOG("-> 0x%x\n", STATUS_SUCCESS);
 	return STATUS_SUCCESS;
 }

dll/rpcrt4.cpp

@@ -2,6 +2,7 @@
 
 #include "common.h"
 #include "context.h"
+#include "heap.h"
 #include "modules.h"
 
 #include <cstdarg>
@@ -125,7 +126,7 @@ RPC_STATUS WINAPI RpcStringBindingComposeW(RPC_WSTR objUuid, RPC_WSTR protSeq, R
 
 	if (stringBinding) {
 		size_t length = encoded.size();
-		auto *buffer = static_cast<char16_t *>(std::malloc((length + 1) * sizeof(char16_t)));
+		auto *buffer = static_cast<char16_t *>(wibo::heap::guestMalloc((length + 1) * sizeof(char16_t)));
 		if (!buffer) {
 			return RPC_S_OUT_OF_MEMORY;
 		}

src/context.h

@@ -1,4 +1,3 @@
 #pragma once
 
 #define HOST_CONTEXT_GUARD()
-#define GUEST_CONTEXT_GUARD(tibPtr)

src/entry.h

@@ -5,3 +5,9 @@
 typedef VOID(_CC_CDECL *EntryProc)();
 typedef BOOL(_CC_STDCALL *DllEntryProc)(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpReserved);
 typedef VOID(_CC_STDCALL *PIMAGE_TLS_CALLBACK)(PVOID DllHandle, DWORD Reason, PVOID Reserved);
+
+namespace entry {
+
+void CDECL stubBase(SIZE_T index);
+
+} // namespace entry

src/heap.h

@@ -0,0 +1,53 @@
+#pragma once
+
+#include "types.h"
+
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+
+struct mi_heap_s;
+typedef struct mi_heap_s mi_heap_t;
+
+namespace wibo::heap {
+
+bool initialize();
+uintptr_t systemPageSize();
+uintptr_t allocationGranularity();
+mi_heap_t *getGuestHeap();
+mi_heap_t *createGuestHeap();
+
+enum class VmStatus : uint32_t {
+	Success = 0,
+	InvalidParameter,
+	InvalidAddress,
+	NoAccess,
+	NotSupported,
+	NoMemory,
+	Rejected,
+	UnknownError,
+};
+
+// Guest heap memory allocation helpers
+void *guestMalloc(std::size_t size);
+void *guestCalloc(std::size_t count, std::size_t size);
+void *guestRealloc(void *ptr, std::size_t newSize);
+void guestFree(void *ptr);
+
+VmStatus virtualAlloc(void **baseAddress, std::size_t *regionSize, DWORD allocationType, DWORD protect,
+					  DWORD type = MEM_PRIVATE);
+VmStatus virtualFree(void *baseAddress, std::size_t regionSize, DWORD freeType);
+VmStatus virtualProtect(void *baseAddress, std::size_t regionSize, DWORD newProtect, DWORD *oldProtect);
+VmStatus virtualQuery(const void *address, MEMORY_BASIC_INFORMATION *outInfo);
+VmStatus virtualReset(void *baseAddress, std::size_t regionSize);
+
+VmStatus reserveViewRange(std::size_t regionSize, uintptr_t minAddr, uintptr_t maxAddr, void **baseAddress);
+void registerViewRange(void *baseAddress, std::size_t regionSize, DWORD allocationProtect, DWORD protect);
+void releaseViewRange(void *baseAddress);
+
+DWORD win32ErrorFromVmStatus(VmStatus status);
+NTSTATUS ntStatusFromVmStatus(VmStatus status);
+
+bool reserveGuestStack(std::size_t stackSizeBytes, void **outStackLimit, void **outStackBase);
+
+} // namespace wibo::heap

src/loader.cpp

@@ -1,12 +1,13 @@
 #include "common.h"
 #include "errors.h"
+#include "heap.h"
 #include "kernel32/internal.h"
 #include "modules.h"
+#include "types.h"
 
 #include <algorithm>
 #include <cstring>
 #include <strings.h>
-#include <sys/mman.h>
 #include <sys/syscall.h>
 #include <unistd.h>
 
@@ -183,7 +184,7 @@ uint32_t read32(FILE *file) {
 
 wibo::Executable::~Executable() {
 	if (imageBase) {
-		munmap(imageBase, imageSize);
+		wibo::heap::virtualFree(imageBase, 0, MEM_RELEASE);
 		imageBase = nullptr;
 	}
 }
@@ -239,20 +240,28 @@ bool wibo::Executable::loadPE(FILE *file, bool exec) {
 
 	// Build buffer
 	imageSize = header32.sizeOfImage;
-	int prot = PROT_READ | PROT_WRITE;
+	DWORD initialProtect = exec ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE;
-	if (exec)
+	void *preferredBase = reinterpret_cast<void *>(static_cast<uintptr_t>(header32.imageBase));
-		prot |= PROT_EXEC;
+	void *allocatedBase = preferredBase;
-	void *preferredBase = (void *)(uintptr_t)header32.imageBase;
+	std::size_t allocationSize = static_cast<std::size_t>(header32.sizeOfImage);
-	imageBase = mmap(preferredBase, header32.sizeOfImage, prot, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	wibo::heap::VmStatus allocStatus = wibo::heap::virtualAlloc(
-	if (imageBase == MAP_FAILED) {
+		&allocatedBase, &allocationSize, MEM_RESERVE | MEM_COMMIT, initialProtect, MEM_IMAGE);
-		imageBase = mmap(nullptr, header32.sizeOfImage, prot, MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+	if (allocStatus != wibo::heap::VmStatus::Success) {
+		DEBUG_LOG("loadPE: preferred base allocation failed (status=%u), retrying anywhere\n",
+			  static_cast<unsigned>(allocStatus));
+		allocatedBase = nullptr;
+		allocationSize = static_cast<std::size_t>(header32.sizeOfImage);
+		allocStatus = wibo::heap::virtualAlloc(
+			&allocatedBase, &allocationSize, MEM_RESERVE | MEM_COMMIT, initialProtect, MEM_IMAGE);
 	}
-	if (imageBase == MAP_FAILED) {
+	if (allocStatus != wibo::heap::VmStatus::Success) {
-		perror("Image mapping failed!");
+		DEBUG_LOG("Image mapping failed (status=%u)\n", static_cast<unsigned>(allocStatus));
 		imageBase = nullptr;
 		return false;
 	}
-	relocationDelta = (intptr_t)((uintptr_t)imageBase - (uintptr_t)header32.imageBase);
+	imageBase = allocatedBase;
+	relocationDelta =
+		static_cast<intptr_t>(reinterpret_cast<uintptr_t>(imageBase) - static_cast<uintptr_t>(header32.imageBase));
 	memset(imageBase, 0, header32.sizeOfImage);
 	sections.clear();
 	uintptr_t imageBaseAddr = reinterpret_cast<uintptr_t>(imageBase);
@@ -315,7 +324,7 @@ bool wibo::Executable::loadPE(FILE *file, bool exec) {
 	if (exec && relocationDelta != 0) {
 		if (relocationDirectoryRVA == 0 || relocationDirectorySize == 0) {
 			DEBUG_LOG("Relocation required but no relocation directory present\n");
-			munmap(imageBase, imageSize);
+			wibo::heap::virtualFree(imageBase, 0, MEM_RELEASE);
 			imageBase = nullptr;
 			return false;
 		}
@@ -361,9 +370,34 @@ bool wibo::Executable::loadPE(FILE *file, bool exec) {
 }
 
 bool wibo::Executable::resolveImports() {
+	auto finalizeSections = [this]() -> bool {
+		if (!execMapped || sectionsProtected) {
+			return true;
+		}
+		for (const auto &section : sections) {
+			if (section.size == 0) {
+				continue;
+			}
+			void *sectionAddress = reinterpret_cast<void *>(section.base);
+			wibo::heap::VmStatus status =
+				wibo::heap::virtualProtect(sectionAddress, section.size, section.protect, nullptr);
+			if (status != wibo::heap::VmStatus::Success) {
+				DEBUG_LOG("resolveImports: failed to set section protection at %p (size=%zu, protect=0x%x) status=%u\n",
+					  sectionAddress, section.size, section.protect, static_cast<unsigned>(status));
+				kernel32::setLastError(wibo::heap::win32ErrorFromVmStatus(status));
+				return false;
+			}
+		}
+		sectionsProtected = true;
+		return true;
+	};
+
 	if (importsResolved || !execMapped) {
 		importsResolved = true;
 		importsResolving = false;
+		if (!finalizeSections()) {
+			return false;
+		}
 		return true;
 	}
 	if (importsResolving) {
@@ -374,6 +408,9 @@ bool wibo::Executable::resolveImports() {
 	if (!importDirectoryRVA) {
 		importsResolved = true;
 		importsResolving = false;
+		if (!finalizeSections()) {
+			return false;
+		}
 		return true;
 	}
 
@@ -381,6 +418,9 @@ bool wibo::Executable::resolveImports() {
 	if (!dir) {
 		importsResolved = true;
 		importsResolving = false;
+		if (!finalizeSections()) {
+			return false;
+		}
 		return true;
 	}
 
@@ -464,5 +504,9 @@ bool wibo::Executable::resolveImports() {
 
 	importsResolved = true;
 	importsResolving = false;
+	if (!finalizeSections()) {
+		importsResolved = false;
+		return false;
+	}
 	return true;
 }

src/main.cpp

@@ -3,6 +3,7 @@
 #include "entry.h"
 #include "entry_trampolines.h"
 #include "files.h"
+#include "heap.h"
 #include "modules.h"
 #include "processes.h"
 #include "strutil.h"
@@ -501,10 +502,7 @@ int main(int argc, char **argv) {
 	kernel32::setLastError(0);
 
 	// Invoke the damn thing
-	{
+	call_EntryProc(entryPoint);
-		GUEST_CONTEXT_GUARD(&tib);
-		call_EntryProc(entryPoint);
-	}
 	DEBUG_LOG("We came back\n");
 	wibo::shutdownModuleRegistry();
 	wibo::tls::cleanupTib(&tib);

src/modules.cpp

@@ -1,11 +1,11 @@
 #include "modules.h"
 
 #include "common.h"
-#include "context.h"
 #include "entry.h"
 #include "entry_trampolines.h"
 #include "errors.h"
 #include "files.h"
+#include "heap.h"
 #include "kernel32/internal.h"
 #include "msvcrt.h"
 #include "msvcrt_trampolines.h"
@@ -87,16 +87,11 @@ std::string makeStubKey(const char *dllName, const char *funcName) {
 	return key;
 }
 
-void stubBase(size_t index) {
+template <size_t Index> void stubThunk() {
-	const char *func = stubFuncNames[index].empty() ? "<unknown>" : stubFuncNames[index].c_str();
+	// Call the appropriate entry trampoline
-	const char *dll = stubDlls[index].empty() ? "<unknown>" : stubDlls[index].c_str();
+	thunk_entry_stubBase(Index);
-	fprintf(stderr, "wibo: call reached missing import %s from %s\n", func, dll);
-	fflush(stderr);
-	abort();
 }
 
-template <size_t Index> void stubThunk() { stubBase(Index); }
-
 template <size_t... Indices>
 constexpr std::array<void (*)(void), sizeof...(Indices)> makeStubTable(std::index_sequence<Indices...>) {
 	return {{stubThunk<Indices>...}};
@@ -293,7 +288,7 @@ bool allocateModuleTlsForThread(wibo::ModuleInfo &module, TEB *tib) {
 	void *block = nullptr;
 	const size_t allocationSize = info.allocationSize;
 	if (allocationSize > 0) {
-		block = std::malloc(allocationSize);
+		block = wibo::heap::guestMalloc(allocationSize);
 		if (!block) {
 			DEBUG_LOG("  allocateModuleTlsForThread: failed to allocate %zu bytes for %s\n", allocationSize,
 					  module.originalName.c_str());
@@ -716,6 +711,19 @@ void ensureExportsInitialized(wibo::ModuleInfo &info) {
 
 } // namespace
 
+namespace entry {
+
+// Trampoline target for missing imports
+void stubBase(SIZE_T index) {
+	const char *func = stubFuncNames[index].empty() ? "<unknown>" : stubFuncNames[index].c_str();
+	const char *dll = stubDlls[index].empty() ? "<unknown>" : stubDlls[index].c_str();
+	fprintf(stderr, "wibo: call reached missing import %s from %s\n", func, dll);
+	fflush(stderr);
+	abort();
+}
+
+} // namespace entry
+
 namespace wibo {
 
 void initializeModuleRegistry() { registry(); }

src/modules.h

@@ -62,6 +62,7 @@ class Executable {
 	bool execMapped = false;
 	bool importsResolved = false;
 	bool importsResolving = false;
+	bool sectionsProtected = false;
 	std::vector<SectionInfo> sections;
 };
 

src/types.h

@@ -436,3 +436,13 @@ static_assert(offsetof(TEB, LastErrorValue) == 0x34, "LastErrorValue offset mism
 static_assert(offsetof(TEB, GdiTebBatch) == 0x1FC, "GdiTebBatch offset mismatch");
 static_assert(offsetof(TEB, DeallocationStack) == 0xE0C, "DeallocationStack offset mismatch");
 static_assert(offsetof(TEB, TlsSlots) == 0xE10, "TLS slots offset mismatch");
+
+typedef struct _MEMORY_BASIC_INFORMATION {
+	PVOID BaseAddress;
+	PVOID AllocationBase;
+	DWORD AllocationProtect;
+	SIZE_T RegionSize;
+	DWORD State;
+	DWORD Protect;
+	DWORD Type;
+} MEMORY_BASIC_INFORMATION, *PMEMORY_BASIC_INFORMATION;

tools/gen_trampolines.py

@@ -30,6 +30,7 @@ from clang.cindex import (
     CursorKind,
     Index,
     TranslationUnit,
+    Type,
     TypeKind,
     conf,
 )
@@ -97,7 +98,7 @@ class ArgInfo:
     slot_size: int
     primitive: bool
     sign_extended: bool
-    type_str: str
+    type: Type
 
 
 @dataclass
@@ -108,6 +109,7 @@ class FuncInfo:
     source_cc: CallingConv
     target_cc: CallingConv
     variadic: bool
+    return_type: Type
     args: List[ArgInfo] = field(default_factory=list)
 
 
@@ -117,7 +119,7 @@ class TypedefInfo:
     source_cc: CallingConv
     target_cc: CallingConv
     variadic: bool
-    return_type: str
+    return_type: Type
     args: List[ArgInfo] = field(default_factory=list)
 
 
@@ -233,7 +235,7 @@ def _collect_args(func_type: CXType) -> List[ArgInfo]:
                 slot_size=slot_size,
                 primitive=is_primitive,
                 sign_extended=is_sign_extended,
-                type_str=_type_to_string(t),
+                type=t,
             )
         )
     return args
@@ -258,10 +260,11 @@ def collect_functions(tu: TranslationUnit, ns_filter: Optional[str]) -> List[Fun
                 qualified_ns="::".join(ns_parts),
                 name=name,
                 mangled=node.mangled_name or name,
-                args=_collect_args(node.type),
                 source_cc=source_cc,
                 target_cc=_get_function_calling_conv(node.type),
                 variadic=node.type.is_function_variadic(),
+                return_type=node.type.get_result(),
+                args=_collect_args(node.type),
             )
 
         # Recurse into children
@@ -519,8 +522,42 @@ def emit_header_mapping(
 
     # Guest-to-host thunk functions
     for f in funcs:
+        # Generate best-effort function prototype so that simple thunks can be called directly
+        # in special cases (e.g. thunk_entry_stubBase)
+        def _is_opaque(t: Type) -> bool:
+            if (
+                t.kind == TypeKind.RECORD
+                or t.kind == TypeKind.ENUM
+                or t.kind == TypeKind.FUNCTIONPROTO
+                or t.kind == TypeKind.FUNCTIONNOPROTO
+            ):
+                return True
+            return t.kind == TypeKind.POINTER and _is_opaque(
+                t.get_pointee().get_canonical()
+            )
+
+        def _canonical_type_str(t: Type) -> str:
+            c = t.get_canonical()
+            if _is_opaque(c):
+                return "void *"
+            return c.spelling
+
         thunk = f"thunk_{dll}_{f.name}"
-        lines.append(f"void {thunk}(void);")
+        args = []
+        for i, arg in enumerate(f.args):
+            type_str = _canonical_type_str(arg.type)
+            args.append(f"{type_str} arg{i}")
+        param_list = ", ".join(args)
+        return_type = _canonical_type_str(f.return_type)
+        if f.source_cc == CallingConv.X86_STDCALL:
+            cc_attr = "__attribute__((stdcall))"
+        elif f.source_cc == CallingConv.C:
+            cc_attr = "__attribute__((cdecl))"
+        else:
+            raise NotImplementedError(
+                f"Unsupported calling convention {f.source_cc} for function {f.name}"
+            )
+        lines.append(f"{cc_attr} {return_type} {thunk}({param_list});")
 
     # Host-to-guest thunk functions
     for td in typedefs:
@@ -530,7 +567,8 @@ def emit_header_mapping(
 
         params = [f"{td.name} fn"]
         for i, arg in enumerate(td.args):
-            params.append(f"{arg.type_str} arg{i}")
+            type_str = _type_to_string(arg.type)
+            params.append(f"{type_str} arg{i}")
 
         param_list = ", ".join(params)
         lines.append(f"{td.return_type} {thunk}({param_list});")