[Backtracing] Fix Windows assembler related problem.

We need to enable MASM/MARMASM and we need to add a get-cpu-context.asm
file for it to build.

rdar://104336548

Author: al45tair

CMakeLists.txt

@@ -43,7 +43,22 @@ else()
   set(CMAKE_JOB_POOL_LINK local_jobs)
 endif()
 
-ENABLE_LANGUAGE(C)
+enable_language(C)
+enable_language(CXX)
+
+# On Windows, use MASM or MARMASM
+set(SWIFT_ASM_DIALECT ASM)
+set(SWIFT_ASM_EXT S)
+if(CMAKE_SYSTEM_NAME STREQUAL Windows)
+  if(CMAKE_SYSTEM_PROCESSOR MATCHES "ARM64")
+    set(SWIFT_ASM_DIALECT ASM_MARMASM)
+  else()
+    set(SWIFT_ASM_DIALECT ASM_MASM)
+  endif()
+  set(SWIFT_ASM_EXT asm)
+endif()
+
+enable_language(${SWIFT_ASM_DIALECT})
 
 # Use C++14.
 set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
@@ -618,7 +633,7 @@ if("${CMAKE_SOURCE_DIR}" STREQUAL "${CMAKE_CURRENT_SOURCE_DIR}")
 endif()
 
 if(SWIFT_BUILT_STANDALONE)
-  project(Swift C CXX ASM)
+  project(Swift C CXX ${SWIFT_ASM_DIALECT})
 endif()
 
 if(MSVC OR "${CMAKE_SIMULATE_ID}" STREQUAL MSVC)
@@ -688,6 +703,7 @@ execute_process(COMMAND ${CMAKE_MAKE_PROGRAM} ${version_flag}
 message(STATUS "CMake Make Program (${CMAKE_MAKE_PROGRAM}) Version: ${_CMAKE_MAKE_PROGRAM_VERSION}")
 message(STATUS "C Compiler (${CMAKE_C_COMPILER}) Version: ${CMAKE_C_COMPILER_VERSION}")
 message(STATUS "C++ Compiler (${CMAKE_CXX_COMPILER}) Version: ${CMAKE_CXX_COMPILER_VERSION}")
+message(STATUS "Assembler (${CMAKE_${SWIFT_ASM_DIALECT}_COMPILER}) Version: ${CMAKE_${SWIFT_ASM_DIALECT}_COMPILER_VERSION}")
 if (CMAKE_Swift_COMPILER)
   message(STATUS "Swift Compiler (${CMAKE_Swift_COMPILER}) Version: ${CMAKE_Swift_COMPILER_VERSION}")
 else()

include/swift/Runtime/Backtrace.h

@@ -24,6 +24,16 @@
 
 #include <inttypes.h>
 
+#ifdef _WIN32
+// For DWORD
+#define WIN32_LEAN_AND_MEAN
+#define NOMINMAX
+#include <windows.h>
+
+// For wchar_t
+#include <cwchar>
+#endif
+
 #ifdef __cplusplus
 namespace swift {
 namespace runtime {

stdlib/public/Backtracing/CMakeLists.txt

@@ -25,7 +25,12 @@ set(BACKTRACING_SOURCES
   SymbolicatedBacktrace.swift
   Utils.swift
 
+  get-cpu-context.${SWIFT_ASM_EXT}
+)
+
+set(LLVM_OPTIONAL_SOURCES
   get-cpu-context.S
+  get-cpu-context.asm
 )
 
 add_swift_target_library(swift_Backtracing ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB

stdlib/public/Backtracing/get-cpu-context.asm

@@ -0,0 +1,2 @@
+;;; Placeholder for Windows assembly code
+;;; This uses different syntax from everywhere else :-(