Re: [patch] C6X unwinding/exception handling

Matthias Klose <[email protected]>
Newsgroups gmane.comp.gcc.patches,gmane.comp.gcc.java.devel
Message-ID <[email protected]>
On 10/10/2011 02:23 PM, Paul Brook wrote:
>> Index: libjava/exception.cc
>> ===================================================================
>> --- libjava/exception.cc	(revision 179739)
>> +++ libjava/exception.cc	(working copy)
>> @@ -135,6 +135,7 @@
>>  {
>>    _Unwind_Ptr Start;
>>    _Unwind_Ptr LPStart;
>> +  _Unwind_Ptr ttype_base;
>>    const unsigned char *TType;
>>    const unsigned char *action_table;
>>    unsigned char ttype_encoding;
>> @@ -184,7 +185,7 @@
>>    _Unwind_Ptr ptr;
>>
>>    ptr = (_Unwind_Ptr) (info->TType - (i * 4));
>> -  ptr = _Unwind_decode_target2(ptr);
>> +  ptr = _Unwind_decode_typeinfo_ptr (info->ttype_base, (_Unwind_Word)
>> ptr);
>>
>>    return reinterpret_cast<void **>(ptr);
>>  }
>> @@ -325,6 +326,7 @@
>>
>>    // Parse the LSDA header.
>>    p = parse_lsda_header (context, language_specific_data, &info);
>> +  info.ttype_base = base_of_encoded_value (info.ttype_encoding, context);
>>  #ifdef HAVE_GETIPINFO
>>    ip = _Unwind_GetIPInfo (context, &ip_before_insn);
>>  #else
> 
> No.  The purpose of my patch was to remove the arm specific code.
> 
> The only difference I can see in this bit of code is that libstdc++ uses 
> base_of_encoded_value/read_encoded_value_with_base whereas libjava uses 
> context/read_encoded_value.
> 
> I expect you want something like the patch below (completely untested).

I checked the attached patch, test results at
http://gcc.gnu.org/ml/gcc-testresults/2011-10/msg01377.html

which are the same as with my suggested patch.

Ok for the trunk?

 Matthias
exc.diff (text/plain, 3 KB)
libjava/
2011-10-17  Paul Brook  <[email protected]>

	* exception.cc (parse_lsda_header): hardcode ttype_encoding for older
	ARM EABI toolchains.
	(get_ttype_entry) Remove __ARM_EABI_UNWINDER__ variant.

libobjc/
2011-10-17  Paul Brook  <[email protected]>
	    Matthias Klose  <[email protected]>

	* exception.c (parse_lsda_header): hardcode ttype_encoding for older
	ARM EABI toolchains.
	(get_ttype_entry) Remove __ARM_EABI_UNWINDER__ variant.

Index: libjava/exception.cc
===================================================================
--- libjava/exception.cc	(revision 180086)
+++ libjava/exception.cc	(working copy)
@@ -161,6 +161,11 @@
   info->ttype_encoding = *p++;
   if (info->ttype_encoding != DW_EH_PE_omit)
     {
+#if _GLIBCXX_OVERRIDE_TTYPE_ENCODING
+      /* Older ARM EABI toolchains set this value incorrectly, so use a
+	 hardcoded OS-specific format.  */
+  info->ttype_encoding = _GLIBCXX_OVERRIDE_TTYPE_ENCODING;
+#endif
       p = read_uleb128 (p, &tmp);
       info->TType = p + tmp;
     }
@@ -176,22 +181,7 @@
   return p;
 }
 
-#ifdef __ARM_EABI_UNWINDER__
-
 static void **
-get_ttype_entry(_Unwind_Context *, lsda_header_info* info, _uleb128_t i)
-{
-  _Unwind_Ptr ptr;
-
-  ptr = (_Unwind_Ptr) (info->TType - (i * 4));
-  ptr = _Unwind_decode_target2(ptr);
-  
-  return reinterpret_cast<void **>(ptr);
-}
-
-#else
-
-static void **
 get_ttype_entry (_Unwind_Context *context, lsda_header_info *info, long i)
 {
   _Unwind_Ptr ptr;
@@ -202,8 +192,6 @@
   return reinterpret_cast<void **>(ptr);
 }
 
-#endif
-
 // Using a different personality function name causes link failures
 // when trying to mix code using different exception handling models.
 #ifdef SJLJ_EXCEPTIONS

Index: libobjc/exception.c
===================================================================
--- libobjc/exception.c	(revision 180086)
+++ libobjc/exception.c	(working copy)
@@ -159,6 +159,11 @@
   info->ttype_encoding = *p++;
   if (info->ttype_encoding != DW_EH_PE_omit)
     {
+#if _GLIBCXX_OVERRIDE_TTYPE_ENCODING
+      /* Older ARM EABI toolchains set this value incorrectly, so use a
+	 hardcoded OS-specific format.  */
+      info->ttype_encoding = _GLIBCXX_OVERRIDE_TTYPE_ENCODING;
+#endif
       p = read_uleb128 (p, &tmp);
       info->TType = p + tmp;
     }
@@ -174,27 +179,7 @@
   return p;
 }
 
-#ifdef __ARM_EABI_UNWINDER__
-
 static Class
-get_ttype_entry (struct lsda_header_info *info, _uleb128_t i)
-{
-  _Unwind_Ptr ptr;
-  
-  ptr = (_Unwind_Ptr) (info->TType - (i * 4));
-  ptr = _Unwind_decode_target2 (ptr);
-
-  /* NULL ptr means catch-all.  Note that if the class is not found,
-     this will abort the program.  */
-  if (ptr)
-    return objc_getRequiredClass ((const char *) ptr);
-  else
-    return 0;
-}
-
-#else
-
-static Class
 get_ttype_entry (struct lsda_header_info *info, _Unwind_Word i)
 {
   _Unwind_Ptr ptr;
@@ -211,8 +196,6 @@
     return 0;
 }
 
-#endif
-
 /* Using a different personality function name causes link failures
    when trying to mix code using different exception handling
    models.  */
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