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A ton of changes to improve C++ debugging. See ChangeLog.

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Note new nested type changes.
This commit is contained in:
Per Bothner 1992-09-04 07:38:03 +00:00
parent 35fcebce93
commit 472f247723
1 changed files with 80 additions and 11 deletions
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91
gdb/doc/stabs.texinfo
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@ -1493,11 +1493,12 @@ entry now holds an absolute address.
* Class instance::
* Methods:: Method definition
* Protections::
* Method Modifiers:: (const, volatile, const volatile)
* Virtual Methods::
* Inheritence::
* Virtual Base Classes::
* Static Members::
* Method modifiers:: (const, volatile, const volatile)
* Virtual methods::
* Inheritance::
* Virtual base classes::
* Static members::
* Nested types::
@end menu
@ -1517,7 +1518,6 @@ method type (two ## if minimal debug)
cross-reference
@end table
@node Basic C++ types
@section Basic types for C++
@ -1946,8 +1946,8 @@ class. This is preceeded by `~%' and followed by a final semi-colon.
.stabs "A:t20=s8Adat:1,0,32;$vf20:21=*22=ar1;0;1;17,32;A_virt::23=##1;:i;2A*-2147483647;20;;;~%20;",128,0,0,0
@end example
@node Inheritence
@section Inheritence
@node Inheritance
@section Inheritance
Stabs describing C++ derived classes include additional sections that
describe the inheritence hierarchy of the class. A derived class stab
@ -2045,7 +2045,7 @@ the derivation of this class is encoded as follows.
28;;D_virt::32:i;2A*-2147483646;31;;;~%20;",128,0,0,0
@end smallexample
@node Virtual Base Classes
@node Virtual base classes
@section Virtual Base Classes
A derived class object consists of a concatination in memory of the
@ -2096,13 +2096,82 @@ at 128, and Ddat at 160.
@node Static Members
@section Static Members
The data area for a class is a concatination of the space used by the
<< re-arrange - this has nothing to do with static members >>
The data area for a class is a concatenation of the space used by the
data members of the class. If the class has virtual methods a vtable
pointer follows the class data. The field offset part of each field
description in the class stab shows this ordering.
description in the class stab shows this ordering.
<< how is this reflected in stabs? >>
@node Nested types
@section Nested types
C++ allows a type to be defined nested "inside" a class.
Such types follow the same naming rule as class members:
The name of a nested type is only visible inside the class,
or when qualified using @code{::} notation. In that respect,
a nested type "member" is rather like a static member.
In fact, the stabs syntax used for nested types is similar to
that used for static members.
@example
class ios @{
public:
enum io_state @{
goodbit = 0,
eofbit = 1,
failbit = 2,
badbit = 4 @};
io_state state;
@};
ios::io_state Fail()
@{
return ios::failbit;
@}
ios my_ios;
@end example
The relevant part of the assembly code is:
@example
.stabs "'ios::io_state':T20=ebadbit:4,failbit:2,eofbit:1,goodbit:0,;",128,0,0,0
.stabs "'ios::io_state':t20",128,0,0,0
.stabs "ios:T21=s4state:20,0,32;io_state:/220:!'ios::io_state';;",128,0,0,0
.stabs "ios:Tt21",128,0,0,0
.stabs "Fail__Fv:F20",36,0,0,_Fail__Fv
.stabs "my_ios:G21",32,0,0,0
.common _my_ios,4,"bss"
@end example
The first line declares type 20 to be an enum. It gives it the
name @code{ios::io_state}. Single quotes surround the name,
because of the embedded @code{::}. (The name is needed when printing
the type.)
The second line enters the same name into the typedef name space.
(This is useless - only @code{ios} is a real global name.)
The third line defined the @code{ios} type.
The text @code{io_state:/220:!'ios::io_state';} declares that
@code{io_state} is a type "member". The @code{/2} specifies
public visibility, just like a regular member.
This is followed by the type being defined (type 20), the
magic characters @code{:!} to indicate that we're declaring a nested
type, followed by the complete name of the type (again, in single quotes).
Possible optimization: Replace first 3 lines by:
@example
.stabs ":T20=ebadbit:4,failbit:2,eofbit:1,goodbit:0,;",128,0,0,0
.stabs "ios:T21=s4state:20,0,32;io_state:/220:!'ios::io_state';;",128,0,0,0
@end example
This makes type 20 an anonymous type, until the @code{io_state} field
for type 21 is seen; that allows the debugger to back-patch the name of
type 20 to @code{ios::io_state}.
@node Example2.c
@appendix Example2.c - source code for extended example