Investigate extending /ALTERNATENAME to the entire multiverse

Alex Guteniev (@AlexGuteniev)

Currently, the /ALTERNATENAME technique introduced in #2381 isn't used for Clang and ARM64EC:

Lines 498 to 505 in 0dc93fc

    
           #if defined(_M_CEE) || defined(_M_ARM64EC) || defined(_M_HYBRID) \
 
               || defined(__clang__) // TRANSITION, Clang doesn't recognize /ALTERNATENAME, not yet reported
 
           #define _WINDOWS_API              __stdcall
 
           #define _RENAME_WINDOWS_API(_Api) _Api##_clr
 
           #else // ^^^ use forwarders / use /ALTERNATENAME vvv
 
           #define _WINDOWS_API              __declspec(dllimport) __stdcall
 
           #define _RENAME_WINDOWS_API(_Api) _Api
 
           #endif // ^^^ use /ALTERNATENAME ^^^

STL/stl/src/xonce2.cpp

Lines 33 to 43 in 0dc93fc

    
           #if defined(_M_ARM64EC) || defined(_M_HYBRID) 
        
           // <mutex> uses the forwarder fallbacks for ARM64EC and CHPE. 
        
           #elif defined(_M_IX86) 
        
           #pragma comment(linker, "/ALTERNATENAME:__imp____std_init_once_begin_initialize@16=__imp__InitOnceBeginInitialize@16") 
        
           #pragma comment(linker, "/ALTERNATENAME:__imp____std_init_once_complete@12=__imp__InitOnceComplete@12") 
        
           #elif defined(_M_X64) || defined(_M_ARM) || defined(_M_ARM64) 
        
           #pragma comment(linker, "/ALTERNATENAME:__imp___std_init_once_begin_initialize=__imp_InitOnceBeginInitialize") 
        
           #pragma comment(linker, "/ALTERNATENAME:__imp___std_init_once_complete=__imp_InitOnceComplete") 
        
           #else // ^^^ known architecture / unknown architecture vvv 
        
           #error Unknown architecture 
        
           #endif // ^^^ unknown architecture ^^^

We should investigate extending this technique to them. We'll need to:

File an internal issue to get this highly useful linker option documented.
Report an issue upstream to Clang so they can handle it correctly (according to my vague understanding, they just need to pass it along to link.exe, as we aren't using their lld-link.exe here).

We also don't use it for CHPE and /clr, but we don't need to extend it to them.

Finally, as Alex Guteniev (@AlexGuteniev) noted in #2381 (comment) , we could begin using this technique for shared_mutex and possibly elsewhere:

STL/stl/src/sharedmutex.cpp

Lines 20 to 42 in 0dc93fc

    
           void __cdecl _Smtx_lock_exclusive(_Smtx_t* smtx) { // lock shared mutex exclusively 
        
               AcquireSRWLockExclusive(reinterpret_cast<PSRWLOCK>(smtx)); 
        
           } 
        
           void __cdecl _Smtx_lock_shared(_Smtx_t* smtx) { // lock shared mutex non-exclusively 
        
               AcquireSRWLockShared(reinterpret_cast<PSRWLOCK>(smtx)); 
        
           } 
        
           int __cdecl _Smtx_try_lock_exclusive(_Smtx_t* smtx) { // try to lock shared mutex exclusively 
        
               return TryAcquireSRWLockExclusive(reinterpret_cast<PSRWLOCK>(smtx)); 
        
           } 
        
           int __cdecl _Smtx_try_lock_shared(_Smtx_t* smtx) { // try to lock shared mutex non-exclusively 
        
               return TryAcquireSRWLockShared(reinterpret_cast<PSRWLOCK>(smtx)); 
        
           } 
        
           void __cdecl _Smtx_unlock_exclusive(_Smtx_t* smtx) { // unlock exclusive shared mutex 
        
               ReleaseSRWLockExclusive(reinterpret_cast<PSRWLOCK>(smtx)); 
        
           } 
        
           void __cdecl _Smtx_unlock_shared(_Smtx_t* smtx) { // unlock non-exclusive shared mutex 
        
               ReleaseSRWLockShared(reinterpret_cast<PSRWLOCK>(smtx)); 
        
           }

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Investigate extending `/ALTERNATENAME` to the entire multiverse #2469

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	#if defined(_M_CEE) \|\| defined(_M_ARM64EC) \|\| defined(_M_HYBRID) \
	\|\| defined(__clang__) // TRANSITION, Clang doesn't recognize /ALTERNATENAME, not yet reported
	#define _WINDOWS_API __stdcall
	#define _RENAME_WINDOWS_API(_Api) _Api##_clr
	#else // ^^^ use forwarders / use /ALTERNATENAME vvv
	#define _WINDOWS_API __declspec(dllimport) __stdcall
	#define _RENAME_WINDOWS_API(_Api) _Api
	#endif // ^^^ use /ALTERNATENAME ^^^

	#if defined(_M_ARM64EC) \|\| defined(_M_HYBRID)
	// <mutex> uses the forwarder fallbacks for ARM64EC and CHPE.
	#elif defined(_M_IX86)
	#pragma comment(linker, "/ALTERNATENAME:__imp____std_init_once_begin_initialize@16=__imp__InitOnceBeginInitialize@16")
	#pragma comment(linker, "/ALTERNATENAME:__imp____std_init_once_complete@12=__imp__InitOnceComplete@12")
	#elif defined(_M_X64) \|\| defined(_M_ARM) \|\| defined(_M_ARM64)
	#pragma comment(linker, "/ALTERNATENAME:__imp___std_init_once_begin_initialize=__imp_InitOnceBeginInitialize")
	#pragma comment(linker, "/ALTERNATENAME:__imp___std_init_once_complete=__imp_InitOnceComplete")
	#else // ^^^ known architecture / unknown architecture vvv
	#error Unknown architecture
	#endif // ^^^ unknown architecture ^^^

	void __cdecl _Smtx_lock_exclusive(_Smtx_t* smtx) { // lock shared mutex exclusively
	AcquireSRWLockExclusive(reinterpret_cast<PSRWLOCK>(smtx));
	}

	void __cdecl _Smtx_lock_shared(_Smtx_t* smtx) { // lock shared mutex non-exclusively
	AcquireSRWLockShared(reinterpret_cast<PSRWLOCK>(smtx));
	}

	int __cdecl _Smtx_try_lock_exclusive(_Smtx_t* smtx) { // try to lock shared mutex exclusively
	return TryAcquireSRWLockExclusive(reinterpret_cast<PSRWLOCK>(smtx));
	}

	int __cdecl _Smtx_try_lock_shared(_Smtx_t* smtx) { // try to lock shared mutex non-exclusively
	return TryAcquireSRWLockShared(reinterpret_cast<PSRWLOCK>(smtx));
	}

	void __cdecl _Smtx_unlock_exclusive(_Smtx_t* smtx) { // unlock exclusive shared mutex
	ReleaseSRWLockExclusive(reinterpret_cast<PSRWLOCK>(smtx));
	}

	void __cdecl _Smtx_unlock_shared(_Smtx_t* smtx) { // unlock non-exclusive shared mutex
	ReleaseSRWLockShared(reinterpret_cast<PSRWLOCK>(smtx));
	}

Investigate extending /ALTERNATENAME to the entire multiverse #2469

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Investigate extending `/ALTERNATENAME` to the entire multiverse #2469