Author: dim
Date: Thu Feb 26 07:20:05 2015
New Revision: 279307
URL: https://svnweb.freebsd.org/changeset/base/279307

Log:
  Make libcxxrt's parsing of DWARF exception handling tables work on
  architectures with strict alignment, by using memcpy() instead of
  directly reading fields.
  
  Reported by:  Daisuke Aoyama <[email protected]>
  Reviewed by:  imp, bapt
  Tested by:    bapt
  MFC after:    3 days
  Differential Revision: https://reviews.freebsd.org/D1967

Modified:
  head/contrib/libcxxrt/dwarf_eh.h

Modified: head/contrib/libcxxrt/dwarf_eh.h
==============================================================================
--- head/contrib/libcxxrt/dwarf_eh.h    Thu Feb 26 02:22:47 2015        
(r279306)
+++ head/contrib/libcxxrt/dwarf_eh.h    Thu Feb 26 07:20:05 2015        
(r279307)
@@ -218,15 +218,17 @@ static int64_t read_sleb128(dw_eh_ptr_t 
 static uint64_t read_value(char encoding, dw_eh_ptr_t *data)
 {
        enum dwarf_data_encoding type = get_encoding(encoding);
-       uint64_t v;
        switch (type)
        {
                // Read fixed-length types
 #define READ(dwarf, type) \
                case dwarf:\
-                       v = 
static_cast<uint64_t>(*reinterpret_cast<type*>(*data));\
-                       *data += sizeof(type);\
-                       break;
+               {\
+                       type t;\
+                       memcpy(&t, *data, sizeof t);\
+                       *data += sizeof t;\
+                       return static_cast<uint64_t>(t);\
+               }
                READ(DW_EH_PE_udata2, uint16_t)
                READ(DW_EH_PE_udata4, uint32_t)
                READ(DW_EH_PE_udata8, uint64_t)
@@ -237,15 +239,11 @@ static uint64_t read_value(char encoding
 #undef READ
                // Read variable-length types
                case DW_EH_PE_sleb128:
-                       v = read_sleb128(data);
-                       break;
+                       return read_sleb128(data);
                case DW_EH_PE_uleb128:
-                       v = read_uleb128(data);
-                       break;
+                       return read_uleb128(data);
                default: abort();
        }
-
-       return v;
 }
 
 /**
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