Remove CoreCLR PAL semaphore support

src/coreclr/dlls/mscordac/mscordac_unixexports.src

@@ -62,7 +62,6 @@ nativeStringResourceTable_mscorrc
 #CreateFileW
 #CreateEventW
 #CreateEventExW
-#CreateSemaphoreExW
 #CreateThread
 #CloseHandle
 #DebugBreak
@@ -98,7 +97,6 @@ nativeStringResourceTable_mscorrc
 #RaiseException
 #RaiseFailFastException
 #ReadFile
-#ReleaseSemaphore
 #ResetEvent
 #ResumeThread
 #SearchPathW

src/coreclr/inc/clrhost.h

@@ -148,4 +148,36 @@ inline BOOL IsInCantAllocStressLogRegion()
     return t_CantAllocCount != 0;
 }
 
+extern thread_local size_t t_CantStopCount;
+
+// For debugging, we can track arbitrary Can't-Stop regions.
+// In V1.0, this was on the Thread object, but we need to track this for threads w/o a Thread object.
+FORCEINLINE void IncCantStopCount()
+{
+    t_CantStopCount++;
+}
+
+FORCEINLINE void DecCantStopCount()
+{
+    t_CantStopCount--;
+}
+
+typedef StateHolder<IncCantStopCount, DecCantStopCount> CantStopHolder;
+
+#ifdef _DEBUG
+// For debug-only, this can be used w/ a holder to ensure that we're keeping our CS count balanced.
+// We should never use this w/ control flow.
+inline size_t GetCantStopCount()
+{
+    return t_CantStopCount;
+}
+
+// At places where we know we're calling out to native code, we can assert that we're NOT in a CS region.
+// This is _debug only since we only use it for asserts; not for real code-flow control in a retail build.
+inline bool IsInCantStopRegion()
+{
+    return (GetCantStopCount() > 0);
+}
+#endif // _DEBUG
+
 #endif

src/coreclr/inc/corhost.h

@@ -17,9 +17,6 @@
 
 
 #include "windows.h" // worth to include before mscoree.h so we are guaranteed to pick few definitions
-#ifdef CreateSemaphore
-#undef CreateSemaphore
-#endif
 
 #include "mscoree.h"
 

src/coreclr/inc/corpriv.h

@@ -13,9 +13,6 @@
 #include "corimage.h"
 #include "metadata.h"
 
-
-class UTSemReadWrite;
-
 // Creation function to get IMetaDataDispenser(Ex) interface.
 STDAPI CreateMetaDataDispenser(
     REFIID riid,
@@ -112,8 +109,8 @@ DECLARE_INTERFACE_(IMetaDataHelper, IUnknown)
 
     STDMETHOD_(IUnknown *, GetCachedInternalInterface)(BOOL fWithLock) PURE;    // S_OK or error
     STDMETHOD(SetCachedInternalInterface)(IUnknown * pUnk) PURE;    // S_OK or error
-    STDMETHOD_(UTSemReadWrite*, GetReaderWriterLock)() PURE;   // return the reader writer lock
-    STDMETHOD(SetReaderWriterLock)(UTSemReadWrite * pSem) PURE;
+    STDMETHOD_(minipal_rwlock*, GetReaderWriterLock)() PURE;   // return the reader writer lock
+    STDMETHOD(SetReaderWriterLock)(minipal_rwlock * pLock) PURE;
 };  // IMetaDataHelper
 
 

src/coreclr/inc/metadata.h

@@ -14,10 +14,10 @@
 #define _METADATA_H_
 
 #include "ex.h"
+#include <minipal/rwlock.h>
 
 class IMetaModelCommon;
 class MDInternalRW;
-class UTSemReadWrite;
 
 inline int IsGlobalMethodParentTk(mdTypeDef td)
 {
@@ -950,9 +950,9 @@ DECLARE_INTERFACE_(IMDInternalImport, IUnknown)
     STDMETHOD_(IUnknown *, GetCachedPublicInterface)(BOOL fWithLock) PURE;   // return the cached public interface
     __checkReturn
     STDMETHOD(SetCachedPublicInterface)(IUnknown *pUnk) PURE;  // no return value
-    STDMETHOD_(UTSemReadWrite*, GetReaderWriterLock)() PURE;   // return the reader writer lock
+    STDMETHOD_(minipal_rwlock*, GetReaderWriterLock)() PURE;   // return the reader writer lock
     __checkReturn
-    STDMETHOD(SetReaderWriterLock)(UTSemReadWrite * pSem) PURE;
+    STDMETHOD(SetReaderWriterLock)(minipal_rwlock * pLock) PURE;
 
     STDMETHOD_(mdModule, GetModuleFromScope)() PURE;             // [OUT] Put mdModule token here.
 

src/coreclr/inc/winwrap.h

@@ -25,9 +25,6 @@
 
 #include "palclr.h"
 
-#undef CreateSemaphore
-#define CreateSemaphore(_secattr, _count, _maxcount, _name) CreateSemaphoreExW((_secattr), (_count), (_maxcount), (_name), 0, MAXIMUM_ALLOWED | SYNCHRONIZE | SEMAPHORE_MODIFY_STATE)
-
 #undef GetFileVersionInfo
 #define GetFileVersionInfo(_filename, _handle, _len, _data) GetFileVersionInfoEx(0, (_filename), (_handle), (_len), (_data))
 #undef GetFileVersionInfoSize

src/coreclr/md/compiler/mdutil.cpp

@@ -22,7 +22,7 @@
 #if defined(FEATURE_METADATA_IN_VM)
 
 LOADEDMODULES * LOADEDMODULES::s_pLoadedModules = NULL;
-UTSemReadWrite * LOADEDMODULES::m_pSemReadWrite = NULL;
+minipal_rwlock * LOADEDMODULES::m_pReadWriteLock = NULL;
 
 //---------------------------------------------------------------------------------------
 //
@@ -37,14 +37,15 @@ LOADEDMODULES::InitializeStatics()
     {
         // Initialize global read-write lock
         {
-            NewHolder<UTSemReadWrite> pSemReadWrite = new (nothrow) UTSemReadWrite();
-            IfNullGo(pSemReadWrite);
-            IfFailGo(pSemReadWrite->Init());
+            minipal_rwlock *pReadWriteLock = NULL;
+            IfFailGo(CreateMDReadWriteLock(&pReadWriteLock));
 
-            if (InterlockedCompareExchangeT<UTSemReadWrite *>(&m_pSemReadWrite, pSemReadWrite, NULL) == NULL)
+            if (InterlockedCompareExchangeT<minipal_rwlock *>(&m_pReadWriteLock, pReadWriteLock, NULL) == NULL)
             {   // We won the initialization race
-                pSemReadWrite.SuppressRelease();
+                pReadWriteLock = NULL;
             }
+
+            DestroyMDReadWriteLock(pReadWriteLock);
         }
 
         // Initialize the global instance
@@ -53,7 +54,8 @@ LOADEDMODULES::InitializeStatics()
             IfNullGo(pLoadedModules);
 
             {
-                LOCKWRITE();
+                CMDReadWriteLock lockHolder(m_pReadWriteLock COMMA_INDEBUG(NULL));
+                IfFailGo(lockHolder.LockWrite());
 
                 if (VolatileLoad(&s_pLoadedModules) == NULL)
                 {
@@ -78,7 +80,8 @@ HRESULT LOADEDMODULES::AddModuleToLoadedList(RegMeta * pRegMeta)
     IfFailGo(InitializeStatics());
 
     {
-        LOCKWRITE();
+        CMDReadWriteLock lockHolder(m_pReadWriteLock COMMA_INDEBUG(NULL));
+        IfFailGo(lockHolder.LockWrite());
 
         ppRegMeta = s_pLoadedModules->Append();
         IfNullGo(ppRegMeta);
@@ -110,7 +113,8 @@ BOOL LOADEDMODULES::RemoveModuleFromLoadedList(RegMeta * pRegMeta)
     IfFailGo(InitializeStatics());
 
     {
-        LOCKWRITE();
+        CMDReadWriteLock lockHolder(m_pReadWriteLock COMMA_INDEBUG(NULL));
+        IfFailGo(lockHolder.LockWrite());
 
         // Search for this module in list of loaded modules.
         int count = s_pLoadedModules->Count();
@@ -174,7 +178,8 @@ BOOL LOADEDMODULES::IsEntryInList(
     IfFailGo(InitializeStatics());
 
     {
-        LOCKREAD();
+        CMDReadWriteLock lockHolder(m_pReadWriteLock COMMA_INDEBUG(NULL));
+        IfFailGo(lockHolder.LockRead());
 
         // Loop through each loaded modules
         int count = s_pLoadedModules->Count();
@@ -219,7 +224,8 @@ LOADEDMODULES::ResolveTypeRefWithLoadedModules(
     IfFailGo(InitializeStatics());
 
     {
-        LOCKREAD();
+        CMDReadWriteLock lockHolder(m_pReadWriteLock COMMA_INDEBUG(NULL));
+        IfFailGo(lockHolder.LockRead());
 
         // Get the Nesting hierarchy.
         IfFailGo(ImportHelper::GetNesterHierarchy(
@@ -236,11 +242,11 @@ LOADEDMODULES::ResolveTypeRefWithLoadedModules(
 
             {
                 // Do not lock the TypeRef RegMeta (again), as it is already locked for read by the caller.
-                // The code:UTSemReadWrite will block ReadLock even for thread holding already the read lock if
-                // some other thread is waiting for WriteLock on the same lock. That would cause dead-lock if we
-                // try to lock for read again here.
-                CMDSemReadWrite cSemRegMeta((pRegMeta == pTypeRefRegMeta) ? NULL : pRegMeta->GetReaderWriterLock());
-                IfFailGo(cSemRegMeta.LockRead());
+                // The read-write lock may block a recursive read acquisition while a writer is waiting.
+                CMDReadWriteLock regMetaLock(
+                    (pRegMeta == pTypeRefRegMeta) ? NULL : pRegMeta->GetReaderWriterLock()
+                    COMMA_INDEBUG(pRegMeta->GetMiniMd()));
+                IfFailGo(regMetaLock.LockRead());
 
                 hr = ImportHelper::FindNestedTypeDef(
                     pRegMeta->GetMiniMd(),

src/coreclr/md/compiler/mdutil.h

@@ -38,8 +38,6 @@ class RegMeta;
 // this list.
 //
 //*********************************************************************
-class UTSemReadWrite;
-
 class LOADEDMODULES : public CDynArray<RegMeta *>
 {
 private:
@@ -50,7 +48,7 @@ class LOADEDMODULES : public CDynArray<RegMeta *>
 
 public:
     // Named for locking macros - see code:LOCKREAD
-    static UTSemReadWrite * m_pSemReadWrite;
+    static minipal_rwlock * m_pReadWriteLock;
 
     static HRESULT AddModuleToLoadedList(RegMeta *pRegMeta);
     static BOOL RemoveModuleFromLoadedList(RegMeta *pRegMeta);  // true if found and removed.