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[rfa] PROBLEMS: document 'constructor breakpoint ignored' bug
- From: Michael Elizabeth Chastain <mec at shout dot net>
- To: gdb-patches at sources dot redhat dot com
- Date: Tue, 24 Jun 2003 16:26:29 -0400
- Subject: [rfa] PROBLEMS: document 'constructor breakpoint ignored' bug
This patch documents the notorious "constructor breakpoints ignored"
problem in the gdb PROBLEMS file.
Okay to apply this to mainline?
Okay to apply this to the 6.0 branch?
Michael C
2003-06-24 Michael Chastain <mec@shout.net>
* PROBLEMS: Document pr gdb/1091 and pr gdb/1193,
the "constructor breakpoints ignored" bug.
Index: PROBLEMS
===================================================================
RCS file: /cvs/src/src/gdb/PROBLEMS,v
retrieving revision 1.15
diff -c -3 -r1.15 PROBLEMS
*** PROBLEMS 23 Jun 2003 03:28:13 -0000 1.15
--- PROBLEMS 24 Jun 2003 20:20:53 -0000
***************
*** 3,6 ****
--- 3,21 ----
See also: http://www.gnu.org/software/gdb/bugs/
+ gdb/1091: Constructor breakpoints ignored
+ gdb/1193: g++ 3.3 creates multiple constructors: gdb 5.3 can't set breakpoints
+ When gcc 3.x compiles a C++ constructor or C++ destructor, it generates
+ 2 or 3 different versions of the object code. These versions have
+ unique mangled names (they have to, in order for linking to work), but
+ they have identical source code names, which leads to a great deal of
+ confusion. Specifically, if you set a breakpoint in a constructor or a
+ destructor, gdb will put a breakpoint in one of the versions, but your
+ program may execute the other version. This makes it impossible to set
+ breakpoints reliably in constructors or destructors.
+
+ gcc 3.x generates these multiple object code functions in order to
+ implement virtual base classes. gcc 2.x generated just one object code
+ function with a hidden parameter, but gcc 3.x conforms to a multi-vendor
+ ABI for C++ which requires multiple object code functions.