Delete FEATURE_MULTIREG_RETURN (#116122)

It was made obsolete by earlier thread suspension changes

Co-authored-by: Theodore Tsirpanis <[email protected]>

Author: jkotas

src/coreclr/clrdefinitions.cmake

@@ -6,34 +6,21 @@ endif(FEATURE_JIT)
 
 add_compile_definitions($<$<BOOL:$<TARGET_PROPERTY:DAC_COMPONENT>>:DACCESS_COMPILE>)
 
-if (CLR_CMAKE_TARGET_ARCH_ARM64)
-  if (CLR_CMAKE_TARGET_UNIX)
-    add_definitions(-DFEATURE_EMULATE_SINGLESTEP)
-  endif()
-  add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:FEATURE_MULTIREG_RETURN>)
-elseif (CLR_CMAKE_TARGET_ARCH_ARM)
-  if (CLR_CMAKE_HOST_WIN32 AND NOT DEFINED CLR_CROSS_COMPONENTS_BUILD)
-    # Set this to ensure we can use Arm SDK for Desktop binary linkage when doing native (Arm32) build
-    add_definitions(-D_ARM_WINAPI_PARTITION_DESKTOP_SDK_AVAILABLE)
-    add_definitions(-D_ARM_WORKAROUND_)
-  endif (CLR_CMAKE_HOST_WIN32 AND NOT DEFINED CLR_CROSS_COMPONENTS_BUILD)
-  add_definitions(-DFEATURE_EMULATE_SINGLESTEP)
-elseif (CLR_CMAKE_TARGET_ARCH_RISCV64)
-  add_definitions(-DFEATURE_EMULATE_SINGLESTEP)
-  add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:FEATURE_MULTIREG_RETURN>)
-endif (CLR_CMAKE_TARGET_ARCH_ARM64)
-
 if (CLR_CMAKE_TARGET_UNIX)
 
   if (CLR_CMAKE_TARGET_ARCH_AMD64)
     add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:UNIX_AMD64_ABI>)
-    add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:FEATURE_MULTIREG_RETURN>)
+  elseif (CLR_CMAKE_TARGET_ARCH_ARM64)
+    add_compile_definitions(FEATURE_EMULATE_SINGLESTEP)
   elseif (CLR_CMAKE_TARGET_ARCH_ARM)
     add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:UNIX_ARM_ABI>)
+    add_compile_definitions(FEATURE_EMULATE_SINGLESTEP)
   elseif (CLR_CMAKE_TARGET_ARCH_I386)
     add_compile_definitions($<$<NOT:$<BOOL:$<TARGET_PROPERTY:IGNORE_DEFAULT_TARGET_ARCH>>>:UNIX_X86_ABI>)
   elseif (CLR_CMAKE_TARGET_ARCH_LOONGARCH64)
-    add_definitions(-DFEATURE_EMULATE_SINGLESTEP)
+    add_compile_definitions(FEATURE_EMULATE_SINGLESTEP)
+  elseif (CLR_CMAKE_TARGET_ARCH_RISCV64)
+    add_compile_definitions(FEATURE_EMULATE_SINGLESTEP)
   endif()
 
 endif(CLR_CMAKE_TARGET_UNIX)
@@ -239,7 +226,6 @@ function(set_target_definitions_to_custom_os_and_arch)
     target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE TARGET_UNIX)
     if (TARGETDETAILS_ARCH STREQUAL "x64")
       target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE UNIX_AMD64_ABI)
-      target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE FEATURE_MULTIREG_RETURN)
     elseif ((TARGETDETAILS_ARCH STREQUAL "arm") OR (TARGETDETAILS_ARCH STREQUAL "armel"))
       target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE UNIX_ARM_ABI)
     elseif (TARGETDETAILS_ARCH STREQUAL "x86")
@@ -270,11 +256,9 @@ function(set_target_definitions_to_custom_os_and_arch)
   elseif(TARGETDETAILS_ARCH STREQUAL "arm64")
     target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE TARGET_64BIT)
     target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE TARGET_ARM64)
-    target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE FEATURE_MULTIREG_RETURN)
   elseif(TARGETDETAILS_ARCH STREQUAL "loongarch64")
     target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE TARGET_64BIT)
     target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE TARGET_LOONGARCH64)
-    target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE FEATURE_MULTIREG_RETURN)
   elseif((TARGETDETAILS_ARCH STREQUAL "arm") OR (TARGETDETAILS_ARCH STREQUAL "armel"))
     target_compile_definitions(${TARGETDETAILS_TARGET} PRIVATE TARGET_ARM)
   elseif((TARGETDETAILS_ARCH STREQUAL "riscv64"))

src/coreclr/inc/gcinfotypes.h

@@ -211,15 +211,6 @@ inline bool IsPointerFieldReturnKind(ReturnKind returnKind)
     return (returnKind == RT_Object || returnKind == RT_ByRef);
 }
 
-inline bool IsValidReturnRegister(size_t regNo)
-{
-    return (regNo == 0)
-#ifdef FEATURE_MULTIREG_RETURN
-        || (regNo == 1)
-#endif // FEATURE_MULTIREG_RETURN
-        ;
-}
-
 inline bool IsStructReturnKind(ReturnKind returnKind)
 {
     // Two bits encode integer/ref/float return-kinds.
@@ -260,7 +251,6 @@ inline ReturnKind GetStructReturnKind(ReturnKind reg0, ReturnKind reg1)
 inline ReturnKind ExtractRegReturnKind(ReturnKind returnKind, size_t returnRegOrdinal, bool& moreRegs)
 {
     _ASSERTE(IsValidReturnKind(returnKind));
-    _ASSERTE(IsValidReturnRegister(returnRegOrdinal));
 
     // Return kind of each return register is encoded in two bits at returnRegOrdinal*2 position from LSB
     ReturnKind regReturnKind = (ReturnKind)((returnKind >> (returnRegOrdinal * 2)) & 3);

src/coreclr/vm/amd64/cgencpu.h

@@ -547,13 +547,7 @@ extern "C" void getFPReturn(int fpSize, INT64 *retval);
 
 struct HijackArgs
 {
-#ifndef FEATURE_MULTIREG_RETURN
-    union
-    {
-        ULONG64 Rax;
-        ULONG64 ReturnValue[1];
-    };
-#else // !FEATURE_MULTIREG_RETURN
+#ifdef UNIX_AMD64_ABI
     union
     {
         struct
@@ -563,7 +557,13 @@ struct HijackArgs
         };
         ULONG64 ReturnValue[2];
     };
-#endif // !FEATURE_MULTIREG_RETURN
+#else // UNIX_AMD64_ABI
+    union
+    {
+        ULONG64 Rax;
+        ULONG64 ReturnValue[1];
+    };
+#endif // UNIX_AMD64_ABI
     union
     {
         ULONG64 Rcx;

src/coreclr/vm/threads.h

@@ -392,15 +392,6 @@ BOOL MatchThreadHandleToOsId ( HANDLE h, DWORD osId );
 // unstarted System.Thread), then this instance can be found in the TLS
 // of that physical thread.
 
-// FEATURE_MULTIREG_RETURN is set for platforms where a struct return value
-//                         can be returned in multiple registers
-//                         ex: Windows/Unix ARM/ARM64, Unix-AMD64.
-//
-//
-// UNIX_AMD64_ABI is a specific kind of FEATURE_MULTIREG_RETURN
-//                         specified by SystemV ABI for AMD64
-//
-
 #ifdef FEATURE_HIJACK                                                    // Hijack function returning
 EXTERN_C void STDCALL OnHijackWorker(HijackArgs * pArgs);
 #endif // FEATURE_HIJACK