300-pr17976.patch

這是一個實時嵌入式作業系統 實作了MCS51 ARM等MCU

From: Mark Mitchell <[e-mail]>
Sender: [e-mail]
To: [e-mail]
Subject: C++ PATCH: PR 17976
Date: Thu, 14 Oct 2004 21:24:41 -0700


This was a case where we generated multiple destructor calls for the
same global variable, in the (probably rare) situation that an
"extern" declaration followed the definition.

Tested on i686-pc-linux-gnu, applied on the mainline and on the 3.4
branch.

--
Mark Mitchell
CodeSourcery, LLC
[e-mail]

# DP: 2004-10-14  Mark Mitchell  <[e-mail]>
# DP: 
# DP: 	PR c++/17976
# DP: 	* decl.c (cp_finish_decl): Do not call expand_static_init more
# DP: 	than once for a single variable.
# DP: 
# DP: 2004-10-14  Mark Mitchell  <[e-mail]>
# DP: 
# DP: 	PR c++/17976
# DP: 	* g++.dg/init/dtor3.C: New test.

Index: testsuite/g++.dg/init/dtor3.C
===================================================================
RCS file: testsuite/g++.dg/init/dtor3.C
diff -N testsuite/g++.dg/init/dtor3.C
*** /dev/null	1 Jan 1970 00:00:00 -0000
--- gcc/gcc/testsuite/g++.dg/init/dtor3.C	15 Oct 2004 04:02:22 -0000
***************
*** 0 ****
--- 1,21 ----
+ // PR c++/17976
+ // { dg-do run }
+ 
+ extern "C" void abort();
+ struct A
+ {
+   static int i;
+   A(){}
+   ~A(){i++;if(i>1)abort();}
+ };
+ 
+ int A::i = 0;
+ 
+ A a;
+ extern A a;
+ 
+ int main()
+ {
+   return 0;
+ }
+ 
===================================================================
RCS file: /cvs/gcc/gcc/gcc/cp/decl.c,v
retrieving revision 1.1174.2.26
retrieving revision 1.1174.2.27
diff -u -r1.1174.2.26 -r1.1174.2.27
--- gcc/gcc/cp/decl.c	2004/10/10 21:54:59	1.1174.2.26
+++ gcc/gcc/cp/decl.c	2004/10/15 04:23:46	1.1174.2.27
@@ -4778,6 +4778,7 @@
   tree cleanup;
   const char *asmspec = NULL;
   int was_readonly = 0;
+  bool var_definition_p = false;
 
   if (decl == error_mark_node)
     return;
@@ -4930,6 +4931,11 @@
 	  /* Remember that the initialization for this variable has
 	     taken place.  */
 	  DECL_INITIALIZED_P (decl) = 1;
+	  /* This declaration is the definition of this variable,
+	     unless we are initializing a static data member within
+	     the class specifier.  */
+	  if (!DECL_EXTERNAL (decl))
+	    var_definition_p = true;
 	}
       /* If the variable has an array type, lay out the type, even if
 	 there is no initializer.  It is valid to index through the
@@ -5004,8 +5010,16 @@
 		initialize_local_var (decl, init);
 	    }
 
-	  if (TREE_STATIC (decl))
-	    expand_static_init (decl, init);
+	  /* If a variable is defined, and then a subsequent
+	     definintion with external linkage is encountered, we will
+	     get here twice for the same variable.  We want to avoid
+	     calling expand_static_init more than once.  For variables
+	     that are not static data members, we can call
+	     expand_static_init only when we actually process the
+	     initializer.  It is not legal to redeclare a static data
+	     member, so this issue does not arise in that case.  */
+	  if (var_definition_p && TREE_STATIC (decl))
+	    expand_static_init (decl, init); 
 	}
     finish_end0: