[gcc(refs/vendors/ARM/heads/morello)] Enable building libgcc with capabilities

[gcc(refs/vendors/ARM/heads/morello)] Enable building libgcc with capabilities

[Matthew Malcomson]

https://gcc.gnu.org/g:148fe1c3bc53e7adad23a6e102611b640fe97149

commit 148fe1c3bc53e7adad23a6e102611b640fe97149
Author: Matthew Malcomson <matthew.malcomson@arm.com>
Date:   Mon Aug 9 10:51:49 2021 +0100

    Enable building libgcc with capabilities
    
    In order to try and build binaries, we'll need to build libgcc with
    capabilities.  This commit fixes the last few things that were stopping
    it building at all.  There are likely many functionality problems still
    in libgcc due to mishandling of capabilities and words.  We'll have to
    look into those as and when we find them.
    
    The unwinder is a known problem area since we have not looked into how
    capabilities should be handled there.  There is also the splitting up of
    the type `_Unwind_Word` which at various points in the unwinder seems to
    represent the address type, the type that is stored in a register, and
    the value that gets stored on the DWARF2 stack.
    
    Fixes in this patch are:
    - Define the type that we read DWARF _{s,u}leb128_t types into as being
      the same type as the address value of a capability.
    - Avoid the use of __attribute__ ((mode(pointer))) in emutls.c
    
    We've defined the _{s,u}leb128_t types using a new predefined macro of
    `__SIZEOF_POINTER_OFFSET__`.  This may be temporary.  When we work on
    looking at the uses of these types we plan to look into whether using
    our "address" mode attribute would be satisfactory.

Diff:
---
 gcc/cppbuiltin.c        |  2 ++
 libgcc/emutls.c         |  2 +-
 libgcc/unwind-generic.h | 15 +++++++++++----
 3 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/gcc/cppbuiltin.c b/gcc/cppbuiltin.c
index 61efe9b2b75..8f657dd22b0 100644
--- a/gcc/cppbuiltin.c
+++ b/gcc/cppbuiltin.c
@@ -179,6 +179,8 @@ define_builtin_macros_for_type_sizes (cpp_reader *pfile)
      toplev calls backend_init which is not done with -E switch.  */
   cpp_define_formatted (pfile, "__SIZEOF_POINTER__=%d",
 			1 << ceil_log2 ((POINTER_SIZE + BITS_PER_UNIT - 1) / BITS_PER_UNIT));
+  cpp_define_formatted (pfile, "__SIZEOF_POINTER_OFFSET__=%d",
+			1 << ceil_log2 ((POINTER_OFFSET_SIZE + BITS_PER_UNIT - 1) / BITS_PER_UNIT));
 }
 
 
diff --git a/libgcc/emutls.c b/libgcc/emutls.c
index f8012f6d8d5..5f23e626b94 100644
--- a/libgcc/emutls.c
+++ b/libgcc/emutls.c
@@ -31,7 +31,7 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #include "gthr.h"
 
 typedef unsigned int word __attribute__((mode(word)));
-typedef unsigned int pointer __attribute__((mode(pointer)));
+typedef __UINTPTR_TYPE__ pointer;
 
 struct __emutls_object
 {
diff --git a/libgcc/unwind-generic.h b/libgcc/unwind-generic.h
index d82fa1e8021..bbdfbc75f55 100644
--- a/libgcc/unwind-generic.h
+++ b/libgcc/unwind-generic.h
@@ -252,8 +252,13 @@ extern void * _Unwind_FindEnclosingFunction (void *pc);
   #error "__SIZEOF_LONG__ macro not defined"
 #endif
 
-#ifndef __SIZEOF_POINTER__
-  #error "__SIZEOF_POINTER__ macro not defined"
+#ifndef __SIZEOF_POINTER_OFFSET__
+# ifndef __SIZEOF_POINTER__
+    #error "Neither __SIZEOF_POINTER__ nor __SIZEOF_POINTER_OFFSET__ macro defined"
+#  endif
+#  define __ADDRESS_SIZE __SIZEOF_POINTER__
+#else
+#  define __ADDRESS_SIZE __SIZEOF_POINTER_OFFSET__
 #endif
 
 
@@ -265,16 +270,18 @@ extern void * _Unwind_FindEnclosingFunction (void *pc);
    except when a unsigned long data type on the target machine is not
    capable of storing a pointer.  */
 
-#if __SIZEOF_LONG__ >= __SIZEOF_POINTER__
+#if __SIZEOF_LONG__ >= __ADDRESS_SIZE
   typedef long _sleb128_t;
   typedef unsigned long _uleb128_t;
-#elif __SIZEOF_LONG_LONG__ >= __SIZEOF_POINTER__
+#elif __SIZEOF_LONG_LONG__ >= __ADDRESS_SIZE
   typedef long long _sleb128_t;
   typedef unsigned long long _uleb128_t;
 #else
 # error "What type shall we use for _sleb128_t?"
 #endif
 
+#undef __ADDRESS_SIZE
+
 #if defined (__SEH__) && !defined (__USING_SJLJ_EXCEPTIONS__)
 /* Handles the mapping from SEH to GCC interfaces.  */
 EXCEPTION_DISPOSITION _GCC_specific_handler (PEXCEPTION_RECORD, void *,