A64: Fixes for the veneers emission.

src/a64/assembler-a64.cc

 // Copyright 2013 the V8 project authors. All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
@@ skipping 2530 matching lines @@
 
   int jump_instr = require_jump ? kInstructionSize : 0;
   int size_pool_marker = kInstructionSize;
   int size_pool_guard = kInstructionSize;
   int pool_size = jump_instr + size_pool_marker + size_pool_guard +
     num_pending_reloc_info_ * kPointerSize;
   int needed_space = pool_size + kGap;
 
   // Emit veneers for branches that would go out of range during emission of the
   // constant pool.
-  CheckVeneerPool(require_jump, kVeneerDistanceMargin - pool_size);
+  CheckVeneerPool(require_jump, kVeneerDistanceMargin + pool_size);
 
   Label size_check;
   bind(&size_check);
 
   // Check that the code buffer is large enough before emitting the constant
   // pool (include the jump over the pool, the constant pool marker, the
   // constant pool guard, and the gap to the relocation information).
   while (buffer_space() <= needed_space) {
     GrowBuffer();
   }
@@ skipping 210 matching lines @@
   // code.
 #ifdef ENABLE_DEBUGGER_SUPPORT
   RecordRelocInfo(RelocInfo::CONST_POOL, static_cast<intptr_t>(size));
 #endif
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_A64