Merge pull request #12173 from AdmiralCurtiss/fixed-mapping-assert

Common/MemArena: LazyMemoryRegion fixes.

3 files changed, 17 insertions, 4 deletions

diff --git a/Source/Core/Common/MemArenaAndroid.cpp b/Source/Core/Common/MemArenaAndroid.cpp
index 4a9e2f68b4..bcba64e1e1 100644
--- a/Source/Core/Common/MemArenaAndroid.cpp
+++ b/Source/Core/Common/MemArenaAndroid.cpp
@@ -155,8 +155,11 @@ void* LazyMemoryRegion::Create(size_t size)
 {
   ASSERT(!m_memory);
 
+  if (size == 0)
+    return nullptr;
+
   void* memory = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-  if (!memory)
+  if (memory == MAP_FAILED)
   {
     NOTICE_LOG_FMT(MEMMAP, "Memory allocation of {} bytes failed.", size);
     return nullptr;
@@ -172,7 +175,9 @@ void LazyMemoryRegion::Clear()
 {
   ASSERT(m_memory);
 
-  mmap(m_memory, m_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+  void* new_memory = mmap(m_memory, m_size, PROT_READ | PROT_WRITE,
+                          MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+  ASSERT(new_memory == m_memory);
 }
 
 void LazyMemoryRegion::Release()
diff --git a/Source/Core/Common/MemArenaUnix.cpp b/Source/Core/Common/MemArenaUnix.cpp
index 452c2c50c8..9bf3633ee2 100644
--- a/Source/Core/Common/MemArenaUnix.cpp
+++ b/Source/Core/Common/MemArenaUnix.cpp
@@ -121,8 +121,11 @@ void* LazyMemoryRegion::Create(size_t size)
 {
   ASSERT(!m_memory);
 
+  if (size == 0)
+    return nullptr;
+
   void* memory = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
-  if (!memory)
+  if (memory == MAP_FAILED)
   {
     NOTICE_LOG_FMT(MEMMAP, "Memory allocation of {} bytes failed.", size);
     return nullptr;
@@ -138,7 +141,9 @@ void LazyMemoryRegion::Clear()
 {
   ASSERT(m_memory);
 
-  mmap(m_memory, m_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+  void* new_memory = mmap(m_memory, m_size, PROT_READ | PROT_WRITE,
+                          MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED, -1, 0);
+  ASSERT(new_memory == m_memory);
 }
 
 void LazyMemoryRegion::Release()
diff --git a/Source/Core/Common/MemArenaWin.cpp b/Source/Core/Common/MemArenaWin.cpp
index ebf078f45b..b147ced53f 100644
--- a/Source/Core/Common/MemArenaWin.cpp
+++ b/Source/Core/Common/MemArenaWin.cpp
@@ -445,6 +445,9 @@ void* LazyMemoryRegion::Create(size_t size)
 {
   ASSERT(!m_memory);
 
+  if (size == 0)
+    return nullptr;
+
   void* memory = VirtualAlloc(nullptr, size, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
   if (!memory)
   {