[cfe-dev] Windows .exe from clang + COFF w/o gcc - success with issues

[per at lumai.se]

Hi all,

I have been experimenting with the creation of Win32 executables using 
only MSVC SDK headers, clang, llc and link.exe from MS Visual Studio 
2008. This has uncovered a few issues:

1) VisualStudioWindowsX86_32TargetInfo needs to define 
_STDCALL_SUPPORTED. Otherwise the Win32 API does not get dllimport 
declarations and linking fails. Patch attached.

2) The SDK include directory search fails for me. 
InitHeaderSearch.cpp:getWindowsSDKDir() uses key "InstallationFolder" 
whose contents lacks the final "\include" needed for SDK 6.0a.

3) Compiling the simple test program below causes the resulting llvm 
assembly to include definitions of the functions Int64ShllMod32, 
Int64ShraMod32 and Int64ShrlMod32 although these are neither used or 
referenced in the code. This in turn causes problems in 4):

define x86_stdcallcc i64 @Int64ShllMod32(i64 %Value, i32 %ShiftCount) 
nounwind inlinehint {
entry:
   %retval = alloca i64, align 8                   ; <i64*> [#uses=1]
   %Value.addr = alloca i64, align 8               ; <i64*> [#uses=1]
   %ShiftCount.addr = alloca i32, align 4          ; <i32*> [#uses=1]
   store i64 %Value, i64* %Value.addr
   store i32 %ShiftCount, i32* %ShiftCount.addr
   call void asm sideeffect "FIXME: not done", 
"~{dirflag},~{fpsr},~{flags}"() nounwind, !srcloc !0
   %0 = load i64* %retval                          ; <i64> [#uses=1]
   ret i64 %0
}

4) Parser::FuzzyParseMicrosoftAsmStatement() emits "FIXME: not done" in 
the llvm code above when microsoft assembly is encountered. Changing it 
to emit "/*"FIXME: not done*/" makes the resulting file compile. Patch 
attached.

***

The final Win32 executable works when fixes for the stuff above are 
applied...! I personally find this very cool. Steps to reproduce:

Create test.c:

#include <windows.h>
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR 
lpCmdLine, int nCmdShow) {
	MessageBox(NULL, "hello msgbox world\n", "Title", MB_OK);
	return 0;
}

Run (in the "Visual Studio 2008 Command Prompt" or another working MSVC 
environment):

clang -I <path to SDK/include> -D_STDCALL_SUPPORTED -c -emit-llvm test.c
llc -filetype obj test.o -o test.obj
link test.obj user32.lib msvcrt.lib

link.exe = the MSVC linker

-- 
Per Lindén
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