[deliverable/binutils-gdb.git] / gdb / PROBLEMS


			Known problems in GDB 6.0

		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.
Commit	Line	Data
e2c9a72c	1
f2c06f52	2	Known problems in GDB 6.0
e2c9a72c	3
36cc83a3	4	See also: http://www.gnu.org/software/gdb/bugs/
e2c9a72c	5
e8ac10a6 MC	6	gdb/1091: Constructor breakpoints ignored
e8ac10a6 MC	7	gdb/1193: g++ 3.3 creates multiple constructors: gdb 5.3 can't set breakpoints
e2c9a72c	8
e8ac10a6 MC	9	When gcc 3.x compiles a C++ constructor or C++ destructor, it generates
	10	2 or 3 different versions of the object code. These versions have
	11	unique mangled names (they have to, in order for linking to work), but
	12	they have identical source code names, which leads to a great deal of
	13	confusion. Specifically, if you set a breakpoint in a constructor or a
	14	destructor, gdb will put a breakpoint in one of the versions, but your
	15	program may execute the other version. This makes it impossible to set
	16	breakpoints reliably in constructors or destructors.
	17
	18	gcc 3.x generates these multiple object code functions in order to
	19	implement virtual base classes. gcc 2.x generated just one object code
	20	function with a hidden parameter, but gcc 3.x conforms to a multi-vendor
	21	ABI for C++ which requires multiple object code functions.