Merge branch 'dev' into dev2

include/mimalloc/prim.h

@@ -208,19 +208,20 @@ static inline void mi_prim_tls_slot_set(size_t slot, void* value) mi_attr_noexce
 #elif _WIN32 && MI_WIN_USE_FIXED_TLS && !defined(MI_WIN_USE_FLS)
 
 // On windows we can store the thread-local heap at a fixed TLS slot to avoid
-// thread-local initialization checks in the fast path. This uses a fixed location
+// thread-local initialization checks in the fast path. 
-// in the TCB though (last user-reserved slot by default) which may clash with other applications.
+// We always use the second user TLS slot (the first one is always allocated already),
-
+// and at initialization (`windows/prim.c`) we call TlsAlloc and verify
+// we indeed get the second slot (and fail otherwise).
+// Todo: we could make the Tls slot completely dynamic but that would require
+// an extra read of the static Tls slot instead of using a constant offset.
 #define MI_HAS_TLS_SLOT      2              // 2 = we can reliably initialize the slot (saving a test on each malloc)
 
 #if MI_WIN_USE_FIXED_TLS > 1
 #define MI_TLS_SLOT     (MI_WIN_USE_FIXED_TLS)
 #elif MI_SIZE_SIZE == 4
-#define MI_TLS_SLOT     (0x710)             // Last user-reserved slot <https://en.wikipedia.org/wiki/Win32_Thread_Information_Block>
+#define MI_TLS_SLOT     (0x0E18)            // Second User TLS slot <https://en.wikipedia.org/wiki/Win32_Thread_Information_Block>
-// #define MI_TLS_SLOT  (0xF0C)             // Last TlsSlot (might clash with other app reserved slot)
 #else
-#define MI_TLS_SLOT     (0x888)             // Last user-reserved slot <https://en.wikipedia.org/wiki/Win32_Thread_Information_Block>
+#define MI_TLS_SLOT     (0x1488)            // Second User TLS slot <https://en.wikipedia.org/wiki/Win32_Thread_Information_Block>
-// #define MI_TLS_SLOT  (0x1678)            // Last TlsSlot (might clash with other app reserved slot)
 #endif
 
 static inline void* mi_prim_tls_slot(size_t slot) mi_attr_noexcept {

src/os.c

@@ -1,5 +1,5 @@
 /* ----------------------------------------------------------------------------
-Copyright (c) 2018-2023, Microsoft Research, Daan Leijen
+Copyright (c) 2018-2025, Microsoft Research, Daan Leijen
 This is free software; you can redistribute it and/or modify it under the
 terms of the MIT license. A copy of the license can be found in the file
 "LICENSE" at the root of this distribution.
@@ -152,8 +152,8 @@ static void mi_os_free_huge_os_pages(void* p, size_t size);
 
 static void mi_os_prim_free(void* addr, size_t size, size_t commit_size) {
   mi_assert_internal((size % _mi_os_page_size()) == 0);
-  if (addr == NULL || size == 0) return; // || _mi_os_is_huge_reserved(addr)
+  if (addr == NULL) return; // || _mi_os_is_huge_reserved(addr)
-  int err = _mi_prim_free(addr, size);
+  int err = _mi_prim_free(addr, size);  // allow size==0 (issue #1041)
   if (err != 0) {
     _mi_warning_message("unable to free OS memory (error: %d (0x%x), size: 0x%zx bytes, address: %p)\n", err, err, size, addr);
   }

src/prim/emscripten/prim.c

@@ -1,5 +1,5 @@
 /* ----------------------------------------------------------------------------
-Copyright (c) 2018-2023, Microsoft Research, Daan Leijen, Alon Zakai
+Copyright (c) 2018-2025, Microsoft Research, Daan Leijen, Alon Zakai
 This is free software; you can redistribute it and/or modify it under the
 terms of the MIT license. A copy of the license can be found in the file
 "LICENSE" at the root of this distribution.
@@ -58,7 +58,7 @@ void _mi_prim_mem_init( mi_os_mem_config_t* config) {
 extern void emmalloc_free(void*);
 
 int _mi_prim_free(void* addr, size_t size) {
-  MI_UNUSED(size);
+  if (size==0) return 0;
   emmalloc_free(addr);
   return 0;
 }

src/prim/unix/prim.c

@@ -1,5 +1,5 @@
 /* ----------------------------------------------------------------------------
-Copyright (c) 2018-2023, Microsoft Research, Daan Leijen
+Copyright (c) 2018-2025, Microsoft Research, Daan Leijen
 This is free software; you can redistribute it and/or modify it under the
 terms of the MIT license. A copy of the license can be found in the file
 "LICENSE" at the root of this distribution.
@@ -70,6 +70,7 @@ terms of the MIT license. A copy of the license can be found in the file
 #define MADV_FREE  POSIX_MADV_FREE
 #endif
 
+#define MI_UNIX_LARGE_PAGE_SIZE (2*MI_MiB) // TODO: can we query the OS for this?
 
 //------------------------------------------------------------------------------------
 // Use syscalls for some primitives to allow for libraries that override open/read/close etc.
@@ -156,7 +157,7 @@ void _mi_prim_mem_init( mi_os_mem_config_t* config )
     }
     #endif
   }
-  config->large_page_size = 2*MI_MiB; // TODO: can we query the OS for this?
+  config->large_page_size = MI_UNIX_LARGE_PAGE_SIZE;
   config->has_overcommit = unix_detect_overcommit();
   config->has_partial_free = true;    // mmap can free in parts
   config->has_virtual_reserve = true; // todo: check if this true for NetBSD?  (for anonymous mmap with PROT_NONE)
@@ -186,6 +187,7 @@ void _mi_prim_mem_init( mi_os_mem_config_t* config )
 //---------------------------------------------
 
 int _mi_prim_free(void* addr, size_t size ) {
+  if (size==0) return 0;
   bool err = (munmap(addr, size) == -1);
   return (err ? errno : 0);
 }
@@ -385,6 +387,9 @@ int _mi_prim_alloc(void* hint_addr, size_t size, size_t try_alignment, bool comm
   mi_assert_internal(size > 0 && (size % _mi_os_page_size()) == 0);
   mi_assert_internal(commit || !allow_large);
   mi_assert_internal(try_alignment > 0);
+  if (hint_addr == NULL && size >= 8*MI_UNIX_LARGE_PAGE_SIZE && try_alignment > 1 && _mi_is_power_of_two(try_alignment) && try_alignment < MI_UNIX_LARGE_PAGE_SIZE) {
+    try_alignment = MI_UNIX_LARGE_PAGE_SIZE; // try to align along large page size for larger allocations
+  }
 
   *is_zero = true;
   int protect_flags = (commit ? (PROT_WRITE | PROT_READ) : PROT_NONE);
@@ -428,7 +433,7 @@ int _mi_prim_decommit(void* start, size_t size, bool* needs_recommit) {
   int err = 0;
   // decommit: use MADV_DONTNEED as it decreases rss immediately (unlike MADV_FREE)
   err = unix_madvise(start, size, MADV_DONTNEED);
-  #if !MI_DEBUG && !MI_SECURE
+  #if !MI_DEBUG && MI_SECURE<=2
     *needs_recommit = false;
   #else
     *needs_recommit = true;

src/prim/windows/prim.c

@@ -631,9 +631,21 @@ static void NTAPI mi_win_main(PVOID module, DWORD reason, LPVOID reserved) {
   MI_UNUSED(reserved);
   MI_UNUSED(module);
   #if MI_TLS_SLOT >= 2
-  if ((reason==DLL_PROCESS_ATTACH || reason==DLL_THREAD_ATTACH) && mi_prim_get_default_heap() == NULL) {
+  if (reason==DLL_PROCESS_ATTACH) {
+    const DWORD tls_slot = TlsAlloc();
+    if (tls_slot != 1) { 
+      _mi_error_message(EFAULT, "unable to allocate the second TLS slot (rebuild without MI_WIN_USE_FIXED_TLS?)\n"); 
+    }
+  }
+  if (reason==DLL_PROCESS_ATTACH || reason==DLL_THREAD_ATTACH) {
+    if (mi_prim_get_default_heap() == NULL) {
       _mi_heap_set_default_direct((mi_heap_t*)&_mi_heap_empty);
     }
+    #if MI_DEBUG
+    void* const p = TlsGetValue(1);
+    mi_assert_internal(p == (void*)&_mi_heap_empty);
+    #endif  
+  }
   #endif
   if (reason==DLL_PROCESS_ATTACH) {
     _mi_process_load();

test/main-override-dep.cpp

@@ -1,6 +1,7 @@
 // Issue #981: test overriding allocation in a DLL that is compiled independent of mimalloc. 
 // This is imported by the `mimalloc-test-override` project.
 #include <string>
+#include <iostream>
 #include "main-override-dep.h"
 
 std::string TestAllocInDll::GetString()
@@ -10,6 +11,41 @@ std::string TestAllocInDll::GetString()
 	const char* t = "test";
 	memcpy(test, t, 4);
 	std::string r = test;
+  std::cout << "override-dep: GetString: " << r << "\n";
 	delete[] test;
 	return r;
 }
+
+
+class Static {
+private:
+  void* p;
+public:
+  Static() {
+    printf("override-dep: static constructor\n");
+    p = malloc(64);
+    return;
+  }
+  ~Static() {
+    free(p);
+    printf("override-dep: static destructor\n");
+    return;
+  }
+};
+
+static Static s = Static();
+
+
+#include <windows.h>
+
+BOOL WINAPI DllMain(HINSTANCE module, DWORD reason, LPVOID reserved) {
+  (void)(reserved);
+  (void)(module);
+  if (reason==DLL_PROCESS_ATTACH) {
+    printf("override-dep: dll attach\n");
+  }
+  else if (reason==DLL_PROCESS_DETACH) {
+    printf("override-dep: dll detach\n");
+  }  
+  return TRUE;
+}

test/main-override.cpp

@@ -40,7 +40,7 @@ static void test_thread_local();      // issue #944
 static void test_mixed1();             // issue #942
 static void test_stl_allocators();
 
-#if x_WIN32
+#if _WIN32
 #include "main-override-dep.h"
 static void test_dep();               // issue #981: test overriding in another DLL
 #else
@@ -150,11 +150,12 @@ static bool test_stl_allocator1() {
 struct some_struct { int i; int j; double z; };
 
 
-#if x_WIN32
+#if _WIN32
 static void test_dep()
 {
   TestAllocInDll t;
   std::string s = t.GetString();
+  std::cout << "test_dep GetString: " << s << "\n";
 }
 #endif