From a7370dcbd21f0497bbeb666f22f2e653001ab4c4 Mon Sep 17 00:00:00 2001
From: daanx <daan@effp.org>
Date: Wed, 22 Jan 2025 12:25:02 -0800
Subject: [PATCH] fix highest allocated page for arena unload

---
 src/arena.c                |  9 +++++++--
 test/main-override-dep.cpp | 10 ++++++++++
 test/main-override-dep.h   |  1 +
 test/main-override.cpp     | 10 ++++++----
 4 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/src/arena.c b/src/arena.c
index bcde865e..4ad4bb0e 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -1834,8 +1834,13 @@ mi_decl_export bool mi_arena_unload(mi_arena_id_t arena_id, void** base, size_t*
   size_t asize;
   // scan the commit map for the highest entry
   size_t idx;
-  if (mi_bitmap_bsr(arena->slices_committed, &idx)) {
-    asize = (idx + 1)* MI_ARENA_SLICE_SIZE;
+  //if (mi_bitmap_bsr(arena->slices_committed, &idx)) {
+  //  asize = (idx + 1)* MI_ARENA_SLICE_SIZE;
+  //}
+  if (mi_bitmap_bsr(arena->pages, &idx)) {
+    mi_page_t* page = (mi_page_t*)mi_arena_slice_start(arena, idx);
+    const size_t page_slice_count = page->memid.mem.arena.slice_count;
+    asize = mi_size_of_slices(idx + page_slice_count);
   }
   else {
     asize = mi_arena_info_slices(arena) * MI_ARENA_SLICE_SIZE;
diff --git a/test/main-override-dep.cpp b/test/main-override-dep.cpp
index e92f6fc4..edb57f1f 100644
--- a/test/main-override-dep.cpp
+++ b/test/main-override-dep.cpp
@@ -12,4 +12,14 @@ std::string TestAllocInDll::GetString()
 	std::string r = test;
 	delete[] test;
 	return r;
+}
+
+#include <windows.h>
+
+void TestAllocInDll::TestHeapAlloc()
+{
+	HANDLE heap = GetProcessHeap();
+	int* p = (int*)HeapAlloc(heap, 0, sizeof(int));
+	*p = 42;
+	HeapFree(heap, 0, p);
 }
\ No newline at end of file
diff --git a/test/main-override-dep.h b/test/main-override-dep.h
index 4826f25f..9d4aabfd 100644
--- a/test/main-override-dep.h
+++ b/test/main-override-dep.h
@@ -8,4 +8,5 @@ class TestAllocInDll
 {
 public:
 	__declspec(dllexport) std::string GetString();
+	__declspec(dllexport) void TestHeapAlloc();
 };
diff --git a/test/main-override.cpp b/test/main-override.cpp
index db594acc..af385992 100644
--- a/test/main-override.cpp
+++ b/test/main-override.cpp
@@ -37,7 +37,7 @@ 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
@@ -46,8 +46,8 @@ static void test_dep() { };
 
 int main() {
   mi_stats_reset();  // ignore earlier allocations
-  various_tests();
-  test_mixed1();
+  //various_tests();
+  //test_mixed1();
 
   test_dep();
 
@@ -145,11 +145,13 @@ 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();
+
+  t.TestHeapAlloc();
 }
 #endif