From 44753cf5a30b9324d2c4ac9021843674bde5cc3c Mon Sep 17 00:00:00 2001
From: Justus Winter <4winter@informatik.uni-hamburg.de>
Date: Sun, 15 Feb 2015 13:29:30 +0100
Subject: Do not generate code dereferencing type-punned pointers

For variable-length arrays, up to 2048 bytes are transmitted inline.
If the array is larger, the data is transmitted out-of-line, and a
pointer to a vm_allocated region is stored at the beginning of the
array.

Previously, the generated code casted the field.  Use a union instead.

This fixes the gcc warning `dereferencing type-punned pointer will
break strict-aliasing rules [-Wstrict-aliasing]'.

* global.c (OOLPostfix): New variable.
* global.h (OOLPostfix): New declaration.
* server.c (WriteServerCallArg): Avoid cast.
(WriteDestroyArg): Likewise.
(WritePackArgValue): Likewise.
(WritePackArg): Likewise.
* user.c (WriteExtractArgValue): Likewise.
* utils.c (WriteFieldDeclPrim): Generate a union with an additional
pointer field for variable-length arrays.
---
 global.h | 1 +
 1 file changed, 1 insertion(+)

(limited to 'global.h')

diff --git a/global.h b/global.h
index ca4d865..8dbb6fd 100644
--- a/global.h
+++ b/global.h
@@ -53,6 +53,7 @@ extern const_string_t UserPrefix;
 extern const_string_t ServerDemux;
 extern const_string_t SubrPrefix;
 extern const_string_t RoutinePrefix;
+extern const_string_t OOLPostfix;
 
 extern int yylineno;
 extern string_t yyinname;
-- 
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