[rfa] PROBLEMS: document 'constructor breakpoint ignored' bug

[Michael Elizabeth Chastain <mec@shout.net>]

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.