[Ada] Fix relocation problem in DWARF debug info

[Ada] Fix relocation problem in DWARF debug info

[Eric Botcazou]

[-- Attachment #1: Type: text/plain, Size: 485 bytes --]

With the 4.3.x series and above the compiler emits (more verbose) debug info 
in DWARF for CONST_DECLs.  This can bring about problems for constants coming 
from other compilation units whose initializer is not absolute.

Tested on i586-suse-linux, applied on all active branches.


2009-04-22  Eric Botcazou  <ebotcazou@adacore.com>

	* gcc-interface/utils.c (create_var_decl_1): Do not emit debug info
	for an external constant whose initializer is not absolute.


-- 
Eric Botcazou

[-- Attachment #2: p.diff --]
[-- Type: text/x-diff, Size: 872 bytes --]

Index: gcc-interface/utils.c
===================================================================
--- gcc-interface/utils.c	(revision 146578)
+++ gcc-interface/utils.c	(working copy)
@@ -1348,6 +1348,15 @@ create_var_decl_1 (tree var_name, tree a
   TREE_STATIC (var_decl)
     = !extern_flag && (public_flag || static_flag || global_bindings_p ());
 
+  /* For an external constant whose initializer is not absolute, do not emit
+     debug info.  In DWARF this would mean a global relocation in a read-only
+     section which runs afoul of the PE-COFF runtime relocation mechanism.  */
+  if (extern_flag
+      && constant_p
+      && initializer_constant_valid_p (var_init, TREE_TYPE (var_init))
+	   != null_pointer_node)
+    DECL_IGNORED_P (var_decl) = 1;
+
   if (asm_name && VAR_OR_FUNCTION_DECL_P (var_decl))
     SET_DECL_ASSEMBLER_NAME (var_decl, asm_name);