Avoid an assertion failure in alias.asm

stl/CMakeLists.txt

@@ -263,7 +263,8 @@ set(IMPLIB_SOURCES
     ${CMAKE_CURRENT_LIST_DIR}/src/syserror_import_lib.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/vector_algorithms.cpp
     ${CMAKE_CURRENT_LIST_DIR}/src/xonce2.cpp
-    ${CMAKE_CURRENT_LIST_DIR}/src/alias.asm
+    ${CMAKE_CURRENT_LIST_DIR}/src/alias_init_once_begin_initialize.asm
+    ${CMAKE_CURRENT_LIST_DIR}/src/alias_init_once_complete.asm
 )
 
 # The following files are linked in msvcp140[d][_clr].dll.

stl/msbuild/stl_base/stl.files.settings.targets

@@ -180,7 +180,8 @@ SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
         <!-- Objs that exist in both libcpmt[d][01].lib and msvcprt[d].lib
              (controlled by IncludeInLink and IncludeInImportLib). -->
         <BuildFiles Include="
-            $(CrtRoot)\github\stl\src\alias.asm;
+            $(CrtRoot)\github\stl\src\alias_init_once_begin_initialize.asm;
+            $(CrtRoot)\github\stl\src\alias_init_once_complete.asm;
             ">
             <BuildAs>asm</BuildAs>
             <IncludeInLink>false</IncludeInLink>

stl/src/alias_init_once_begin_initialize.asm

@@ -0,0 +1,26 @@
+; Copyright (c) Microsoft Corporation.
+; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+; weak symbol aliases
+
+; This checks if we're in x64 mode (using ml64).
+; Note that RAX isn't really an assembler symbol,
+; and this check only works in the IFDEF direction.
+; That is:
+; IFDEF RAX
+;   meow
+; ENDIF
+; will expand to meow on only x64 systems, however:
+; IFNDEF RAX
+;   meow
+; ENDIF
+; will expand to meow on _BOTH_ x64 and x86 systems.
+IFDEF RAX
+    EXTERN __imp_InitOnceBeginInitialize : PROC
+    ALIAS <__imp___std_init_once_begin_initialize> = <__imp_InitOnceBeginInitialize>
+ELSE
+    EXTERN __imp__InitOnceBeginInitialize@16 : PROC
+    ALIAS <__imp____std_init_once_begin_initialize@16> = <__imp__InitOnceBeginInitialize@16>
+ENDIF
+
+END

stl/src/alias_init_once_complete.asm

@@ -0,0 +1,26 @@
+; Copyright (c) Microsoft Corporation.
+; SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+; weak symbol aliases
+
+; This checks if we're in x64 mode (using ml64).
+; Note that RAX isn't really an assembler symbol,
+; and this check only works in the IFDEF direction.
+; That is:
+; IFDEF RAX
+;   meow
+; ENDIF
+; will expand to meow on only x64 systems, however:
+; IFNDEF RAX
+;   meow
+; ENDIF
+; will expand to meow on _BOTH_ x64 and x86 systems.
+IFDEF RAX
+    EXTERN __imp_InitOnceComplete : PROC
+    ALIAS <__imp___std_init_once_complete> = <__imp_InitOnceComplete>
+ELSE
+    EXTERN __imp__InitOnceComplete@12 : PROC
+    ALIAS <__imp____std_init_once_complete@12> = <__imp__InitOnceComplete@12>
+ENDIF
+
+END