[libcxxabi] Fix -Werror build for 32-bit non-ARM.

[danalbert]

Summary

The inclusion of Unwind-EHABI.h was insufficiently guarded
(LIBCXXABI_ARM_EHABI was beign checked without ever being defined).

Move the check into the header file itself, add the check to the
source file, and clean up the existing checks.

LIBCXXABI_ARM_EHABI didn't have a canonical defintion; it was
duplicated across cxxabi.h, libunwind.h, and unwind.h. Move the
definition into __cxxabi_config.h and clean up the old cruft (note: we
will have to ship this header).

There are also a few drive-by formatting/whitespace cleanups.

[danalbert]

Diff against master rather than my WIP branch.

[danalbert]

Rebase onto HEAD.

[compnerd]

LGTM with the first suggestion (about readability). I am less worried if you want to merge the drive-by formatting cleanup rather than separating it.

include/__cxxabi_config.h

14

I think this is more readable as:

#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && !defined(__ARM_DWARF_EH__)

That maps to what the condition really is: you need ARM, non-SJLJ, non-DWARF exceptions. Apple uses SJLJ exceptions, so adding !defined(__APPLE__) seems ... repetitive.

src/Unwind/UnwindCursor.hpp

26

Unless Im mistaken, this part looks like it could be split out into a separate change.

src/cxa_exception.cpp

263 ↗

(On Diff #19375)

Along with the previous.

src/cxa_exception.hpp

27 ↗

(On Diff #19375)

And this.

[danalbert]

Moved formatting changes into separate commit (r228360).

[danalbert]

Forgot to address compnerd's readability comment.

[rengolin]

src/Unwind/Unwind-EHABI.h

16

Is this duplication intended?

[danalbert]

src/Unwind/Unwind-EHABI.h

16

Bad merge after splitting/rebasing my change. It was fixed right after in a follow up patch.

[rengolin]

The idea of making this header public may be worrying, if we end up requiring the user to include it. If this is just a matter of compiler-logic, than it should be fine.

src/Unwind/Unwind-EHABI.h

16

I can't see it. Has this change been merged already?

[danalbert]

In D7419#123785, @rengolin wrote:

The idea of making this header public may be worrying, if we end up requiring the user to include it. If this is just a matter of compiler-logic, than it should be fine.

The user will never have to include it manually. It's the job of each header to make sure it is included when needed. I've turned on -Wundef to try to keep us honest about that.

src/Unwind/Unwind-EHABI.h

16

https://github.com/llvm-mirror/libcxxabi/commit/8906bdd7f337749838f9c310e3bb913715c4d12f

[rengolin]

In D7419#123793, @danalbert wrote:

The user will never have to include it manually. It's the job of each header to make sure it is included when needed. I've turned on -Wundef to try to keep us honest about that.

Sounds good. Waiting for Saleems reply on his requests.

cheers,
--renato

src/Unwind/Unwind-EHABI.h

16

Right. You'll squash all of them on the same commit, right?

include/__cxxabi_config.h

+//===-------------------------- __cxxabi_config.h -------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef ____CXXABI_CONFIG_H
+#define ____CXXABI_CONFIG_H
+
+#if defined(__arm__) && !defined(__USING_SJLJ_EXCEPTIONS__) && \
+    !defined(__ARM_DWARF_EH__)
+#define LIBCXXABI_ARM_EHABI 1
+#else
+#define LIBCXXABI_ARM_EHABI 0
+#endif
+
+#endif // ____CXXABI_CONFIG_H

include/cxxabi.h

 /*
  * This header provides the interface to the C++ ABI as defined at:
  *       http://www.codesourcery.com/cxx-abi/
  */
 
 #include <stddef.h>
 #include <stdint.h>
 
+#include <__cxxabi_config.h>
+
 #define _LIBCPPABI_VERSION 1001
 #define LIBCXXABI_NORETURN  __attribute__((noreturn))
 
-// FIXME: This is also in unwind.h and libunwind.h, can we consolidate?
-#if !defined(__USING_SJLJ_EXCEPTIONS__) && defined(__arm__) && \
-    !defined(__ARM_DWARF_EH__) && !defined(__APPLE__)
-#define LIBCXXABI_ARM_EHABI 1
-#else
-#define LIBCXXABI_ARM_EHABI 0
-#endif
-
 #ifdef __cplusplus
 
 namespace std {
 class type_info; // forward declaration
 }
 
 
 // runtime routines use C calling conventions, but are in __cxxabiv1 namespace

include/libunwind.h

 //===----------------------------------------------------------------------===//
 
 #ifndef __LIBUNWIND__
 #define __LIBUNWIND__
 
 #include <stdint.h>
 #include <stddef.h>
 
-// FIXME: This is also in unwind.h and cxxabi.h, can we consolidate?
-#if !defined(__USING_SJLJ_EXCEPTIONS__) && defined(__arm__) && \
-    !defined(__ARM_DWARF_EH__) && !defined(__APPLE__)
-#define LIBCXXABI_ARM_EHABI 1
-#else
-#define LIBCXXABI_ARM_EHABI 0
-#endif
+#include <__cxxabi_config.h>
 
 #ifdef __APPLE__
   #include <Availability.h>
     #ifdef __arm__
        #define LIBUNWIND_AVAIL __attribute__((unavailable))
     #else
       #define LIBUNWIND_AVAIL __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_5_0)
     #endif

include/unwind.h

 #include <stddef.h>
 
 #if defined(__APPLE__)
 #define LIBUNWIND_UNAVAIL __attribute__ (( unavailable ))
 #else
 #define LIBUNWIND_UNAVAIL
 #endif
 
-// FIXME: This is also in cxxabi.h and libunwind.h, can we consolidate?
-#if !defined(__USING_SJLJ_EXCEPTIONS__) && defined(__arm__) && \
-    !defined(__ARM_DWARF_EH__) && !defined(__APPLE__)
-#define LIBCXXABI_ARM_EHABI 1
-#else
-#define LIBCXXABI_ARM_EHABI 0
-#endif
+#include <__cxxabi_config.h>
 
 typedef enum {
   _URC_NO_REASON = 0,
   _URC_OK = 0,
   _URC_FOREIGN_EXCEPTION_CAUGHT = 1,
   _URC_FATAL_PHASE2_ERROR = 2,
   _URC_FATAL_PHASE1_ERROR = 3,
   _URC_NORMAL_STOP = 4,

 _Unwind_VRS_Set(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
                 uint32_t regno, _Unwind_VRS_DataRepresentation representation,
                 void *valuep);
 
 extern _Unwind_VRS_Result
 _Unwind_VRS_Pop(_Unwind_Context *context, _Unwind_VRS_RegClass regclass,
                 uint32_t discriminator,
                 _Unwind_VRS_DataRepresentation representation);
-#endif
 
-#if LIBCXXABI_ARM_EHABI
 static inline uintptr_t _Unwind_GetGR(struct _Unwind_Context* context,
                                       int index) {
   uintptr_t value = 0;
   _Unwind_VRS_Get(context, _UVRSC_CORE, (uint32_t)index, _UVRSD_UINT32, &value);
   return value;
 }
 
 static inline void _Unwind_SetGR(struct _Unwind_Context* context, int index,

src/Unwind/Unwind-EHABI.h

 //===------------------------- Unwind-EHABI.hpp ---------------------------===//
 //
 //                     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.
 //
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef __UNWIND_EHABI_H__
 #define __UNWIND_EHABI_H__
 
+#include <__cxxabi_config.h>
+
+#if LIBCXXABI_ARM_EHABI
+
 #include <stdint.h>
 #include <unwind.h>
 
 #if LIBCXXABI_ARM_EHABI
 
 // Unable to unwind in the ARM index table (section 5 EHABI).
 #define UNW_EXIDX_CANTUNWIND 0x1
 

 
 extern _Unwind_Reason_Code __aeabi_unwind_cpp_pr2(
     _Unwind_State state, _Unwind_Control_Block *ucbp, _Unwind_Context *context);
 
 #if defined(__cplusplus)
 } // extern "C"
 #endif
 
-#endif
+#endif // LIBCXXABI_ARM_EHABI
 
 #endif  // __UNWIND_EHABI_H__

src/Unwind/Unwind-EHABI.cpp

 //===--------------------------- Unwind-EHABI.cpp -------------------------===//
 //
 //                     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.
 //
 //
 //  Implements ARM zero-cost C++ exceptions
 //
 //===----------------------------------------------------------------------===//
 
 #include "Unwind-EHABI.h"
 
-#include <unwind.h>
+#if LIBCXXABI_ARM_EHABI
 
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "config.h"
 #include "libunwind.h"
 #include "libunwind_ext.h"
 #include "unwind.h"
 #include "../private_typeinfo.h"
 
-#if LIBCXXABI_ARM_EHABI
 namespace {
 
 // Strange order: take words in order, but inside word, take from most to least
 // signinficant byte.
 uint8_t getByte(const uint32_t* data, size_t offset) {
   const uint8_t* byteData = reinterpret_cast<const uint8_t*>(data);
   return byteData[(offset & ~(size_t)0x03) + (3 - (offset & (size_t)0x03))];
 }

src/Unwind/UnwindCursor.hpp

 #include <stdlib.h>
 #include <pthread.h>
 #include <unwind.h>
 
 #ifdef __APPLE__
   #include <mach-o/dyld.h>
 #endif
 
-#include "libunwind.h"
+#include "config.h"
 
 #include "AddressSpace.hpp"
-#include "Registers.hpp"
-#include "DwarfInstructions.hpp"
 #include "CompactUnwinder.hpp"
 #include "config.h"
-
-#if LIBCXXABI_ARM_EHABI
+#include "DwarfInstructions.hpp"
+#include "libunwind.h"
+#include "Registers.hpp"
 #include "Unwind-EHABI.h"
-#endif
 
 namespace libunwind {
 
 #if _LIBUNWIND_SUPPORT_DWARF_UNWIND
 /// Cache of recently found FDEs.
 template <typename A>
 class _LIBUNWIND_HIDDEN DwarfFDECache {
   typedef typename A::pint_t pint_t;

src/Unwind/UnwindLevel1-gcc-ext.c

 //===----------------------------------------------------------------------===//
 
 #include <inttypes.h>
 #include <stdbool.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 
-#include "libunwind.h"
-#include "unwind.h"
-#include "libunwind_ext.h"
 #include "config.h"
-
-#if LIBCXXABI_ARM_EHABI
+#include "libunwind_ext.h"
+#include "libunwind.h"
 #include "Unwind-EHABI.h"
-#endif
+#include "unwind.h"
 
 #if _LIBUNWIND_BUILD_ZERO_COST_APIS
 
 ///  Called by __cxa_rethrow().
 _LIBUNWIND_EXPORT _Unwind_Reason_Code
 _Unwind_Resume_or_Rethrow(struct _Unwind_Exception *exception_object) {
 #if LIBCXXABI_ARM_EHABI
   _LIBUNWIND_TRACE_API("_Unwind_Resume_or_Rethrow(ex_obj=%p), "