[clang] [MinGW] Explicitly always pass the -fno-use-init-array (#68571)

On MinGW targets, the .ctors section is always used for constructors.

When using the .ctors section, the constructors need to be emitted in
reverse order to get them execute in the right order. (Constructors with
a specific priority are sorted separately by the linker later.) In LLVM,
in CodeGen/AsmPrinter/AsmPrinter.cpp, there's code that reverses them
before writing them out, executed when using the .ctors section. This
logic is done whenever TM.Options.UseInitArray is set to false. Thus,
make sure to set UseInitArray to false for this target.

This fixes #55938.

Author: mstorsjo

clang/lib/Driver/ToolChains/MinGW.cpp

@@ -709,6 +709,8 @@ void toolchains::MinGW::addClangTargetOptions(
     }
   }
 
+  CC1Args.push_back("-fno-use-init-array");
+
   for (auto Opt : {options::OPT_mthreads, options::OPT_mwindows,
                    options::OPT_mconsole, options::OPT_mdll}) {
     if (Arg *A = DriverArgs.getLastArgNoClaim(Opt))

clang/test/Driver/mingw.cpp

@@ -77,3 +77,6 @@
 // CHECK_NO_SUBSYS-NOT: "--subsystem"
 // CHECK_SUBSYS_CONSOLE: "--subsystem" "console"
 // CHECK_SUBSYS_WINDOWS: "--subsystem" "windows"
+
+// RUN: %clang -target i686-windows-gnu -### %s 2>&1 | FileCheck -check-prefix=CHECK_NO_INIT_ARRAY %s
+// CHECK_NO_INIT_ARRAY: "-fno-use-init-array"