compiler-rt: add support for mingw-w64 in builtins

[martell]

Summary

The is so that we can avoid using libgcc and use compiler-rt with mingw-w64

Related driver patch
http://reviews.llvm.org/D11077

I have tested this with mingw-w64 and everything seems to be in order.
I also sent this patch to the mingw-w64 mailing list for them to look at.

Added Peter as a reviewer as he seems to be the one who commits windows compiler-rt related code :)
Yaron has been commiting all the llvm clang patches for me but has never comitted to compiler-rt before and asked me to find someone else to do this
So I have added Peter as a reviewer :)

[martell]

lib/builtins/CMakeLists.txt

275 ↗

(On Diff #29390)

The only issue I have with my own patch is that I don't know how clang identifies itself to cmake for MSVC targets.
is MSVC still true when no using the cl frontend ?

It might be more correct to change this to

if(NOT WIN32 OR MINGW)

[rnk]

lgtm

lib/builtins/CMakeLists.txt

275 ↗

(On Diff #29390)

It should depend on the default triple.
If you build clang with mingw, it will use the GNU ABI by default (#define GNUC, _Z C++ names, etc).
If you build it with MSVC, it will use the MSVC ABI (#define _MSC_VER, '?' C++ names, etc).

So, for your purposes, this patch is probably fine. :)

lib/builtins/enable_execute_stack.c

53 ↗

(On Diff #29390)

Given that we don't check the return value of mprotect either, it's probably OK to simply ignore failure.

lib/builtins/x86_64/chkstk.S

27 ↗

(On Diff #29390)

s/ecx/rcx/

[martell]

s/ecx/rcx
good spot :)

[martell]

ping? can someone commit this ?

[martell]

compnerd highlighted the fact that this breaks itanium so I updated the patch to fix that

[martell]

Added cfe-commits so that people can actually see the patch on the lists :)
Hopefully someone will consider merging this

[dblaikie]

As phab suggests, you probably want to restart the review if you didn't add
a community list at the time of creation. Phab only sends the initial
summary email with details and attached patch on that first mailing so the
list still has no context here.

[rnk]

I went ahead and landed the patch. I missed the part of the message where you mentioned that Yaron wasn't going to land it. Thanks!

[martell]

Hi rnk thanks for landing it.

its missing the 2 chkstk.S files in the commit ?

[rnk]

In D11085#207187, @martell wrote:

Hi rnk thanks for landing it.

its missing the 2 chkstk.S files in the commit ?

Woops, r242540.

[vadimcn]

Hi!
So apparently LLVM lowers alloca's of large buffers into a call to _alloca (makes sense I guess - if the buffer is larger than a page).
Why wasn't it added along with _chkstk? Is _alloca available from some other mingw library?

compiler-rt/trunk/CMakeLists.txt

 include(CompilerRTUtils)
 
 set(COMPILER_RT_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(COMPILER_RT_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
 # We support running instrumented tests when we're not cross compiling
 # and target a UNIX-like system or Windows.
 # We can run tests on Android even when we are cross-compiling.
-if(("${CMAKE_HOST_SYSTEM}" STREQUAL "${CMAKE_SYSTEM}" AND (UNIX OR MSVC)) OR ANDROID
+if(("${CMAKE_HOST_SYSTEM}" STREQUAL "${CMAKE_SYSTEM}" AND (UNIX OR WIN32)) OR ANDROID
    OR COMPILER_RT_EMULATOR)
   option(COMPILER_RT_CAN_EXECUTE_TESTS "Can we execute instrumented tests" ON)
 else()
   option(COMPILER_RT_CAN_EXECUTE_TESTS "Can we execute instrumented tests" OFF)
 endif()
 
 option(COMPILER_RT_DEBUG "Build runtimes with full debug info" OFF)
 # COMPILER_RT_DEBUG_PYBOOL is used by lit.common.configured.in.

compiler-rt/trunk/lib/builtins/CMakeLists.txt

set(x86_64_SOURCES
   x86_64/floatdidf.c
   x86_64/floatdisf.c
   x86_64/floatdixf.c
   x86_64/floatundidf.S
   x86_64/floatundisf.S
   x86_64/floatundixf.S
   ${GENERIC_SOURCES})
 
+if(WIN32)
+  set(x86_64_SOURCES
+      ${x86_64_SOURCES}
+      x86_64/chkstk.S)
+endif()
+
 set(i386_SOURCES
   i386/ashldi3.S
   i386/ashrdi3.S
   i386/divdi3.S
   i386/floatdidf.S
   i386/floatdisf.S
   i386/floatdixf.S
   i386/floatundidf.S
   i386/floatundisf.S
   i386/floatundixf.S
   i386/lshrdi3.S
   i386/moddi3.S
   i386/muldi3.S
   i386/udivdi3.S
   i386/umoddi3.S
   ${GENERIC_SOURCES})
 
+if(WIN32)
+  set(i386_SOURCES
+      ${i386_SOURCES}
+      i386/chkstk.S)
+endif()
+
 set(i686_SOURCES
   ${i386_SOURCES})
 
 set(arm_SOURCES
   arm/adddf3vfp.S
   arm/addsf3vfp.S
   arm/aeabi_dcmp.S
   arm/aeabi_div0.c
set(arm_SOURCES
   arm/udivsi3.S
   arm/umodsi3.S
   arm/unorddf2vfp.S
   arm/unordsf2vfp.S
   ${GENERIC_SOURCES})
 
 add_custom_target(builtins)
 
-if (NOT WIN32)
+if (NOT WIN32 OR MINGW)
   foreach (arch x86_64 i386 i686 arm)
     if (CAN_TARGET_${arch})
       # Filter out generic versions of routines that are re-implemented in
       # architecture specific manner.  This prevents multiple definitions of the
       # same symbols, making the symbol selection non-deterministic.
       foreach (_file ${${arch}_SOURCES})
         if (${_file} MATCHES ${arch}/*)
           get_filename_component(_name ${_file} NAME)

compiler-rt/trunk/lib/builtins/enable_execute_stack.c

 /* ===-- enable_execute_stack.c - Implement __enable_execute_stack ---------===
  *
  *                     The LLVM Compiler Infrastructure
  *
  * This file is dual licensed under the MIT and the University of Illinois Open
  * Source Licenses. See LICENSE.TXT for details.
  *
  * ===----------------------------------------------------------------------===
  */
 
 #include "int_lib.h"
 
+#ifndef _WIN32
 #include <sys/mman.h>
+#endif
 
 /* #include "config.h"
  * FIXME: CMake - include when cmake system is ready.
  * Remove #define HAVE_SYSCONF 1 line.
  */
 #define HAVE_SYSCONF 1
 
+#ifdef _WIN32
+#include <windef.h>
+#include <winbase.h>
+#else
 #ifndef __APPLE__
 #include <unistd.h>
 #endif /* __APPLE__ */
+#endif /* _WIN32 */
 
 #if __LP64__
   #define TRAMPOLINE_SIZE 48
 #else
   #define TRAMPOLINE_SIZE 40
 #endif
 
 /*
  * The compiler generates calls to __enable_execute_stack() when creating 
  * trampoline functions on the stack for use with nested functions.
  * It is expected to mark the page(s) containing the address 
  * and the next 48 bytes as executable.  Since the stack is normally rw-
  * that means changing the protection on those page(s) to rwx. 
  */
 
 COMPILER_RT_ABI void
 __enable_execute_stack(void* addr)
 {
 
+#if _WIN32
+  MEMORY_BASIC_INFORMATION mbi;
+  if (!VirtualQuery (addr, &mbi, sizeof(mbi)))
+    return; /* We should probably assert here because there is no return value */
+  VirtualProtect (mbi.BaseAddress, mbi.RegionSize, PAGE_EXECUTE_READWRITE, &mbi.Protect);
+#else
 #if __APPLE__
   /* On Darwin, pagesize is always 4096 bytes */
   const uintptr_t pageSize = 4096;
 #elif !defined(HAVE_SYSCONF)
 #error "HAVE_SYSCONF not defined! See enable_execute_stack.c"
 #else
         const uintptr_t pageSize = sysconf(_SC_PAGESIZE);
 #endif /* __APPLE__ */
 
   const uintptr_t pageAlignMask = ~(pageSize-1);
   uintptr_t p = (uintptr_t)addr;
   unsigned char* startPage = (unsigned char*)(p & pageAlignMask);
   unsigned char* endPage = (unsigned char*)((p+TRAMPOLINE_SIZE+pageSize) & pageAlignMask);
   size_t length = endPage - startPage;
   (void) mprotect((void *)startPage, length, PROT_READ | PROT_WRITE | PROT_EXEC);
+#endif
 }