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* stabs.texinfo: Clean up N_{L,R}BRAC. Discuss what addresses of 

N_{L,R}BRAC,N_SLINE are relative to.
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Jim Kingdon 1993-06-12 23:11:31 +00:00
parent 6e6656cc02
commit f0f4b04e1e
2 changed files with 27 additions and 77 deletions
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5
gdb/doc/ChangeLog
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@ -1,3 +1,8 @@
Sat Jun 12 16:09:22 1993 Jim Kingdon (kingdon@cygnus.com)
* stabs.texinfo: Clean up N_{L,R}BRAC. Discuss what addresses of
N_{L,R}BRAC,N_SLINE are relative to.
Fri Jun 11 15:15:55 1993 Jim Kingdon (kingdon@cygnus.com)
* Makefile.in (GDBvn.texi): Update atomically.

99
gdb/doc/stabs.texinfo
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@ -437,7 +437,9 @@ include file. @code{C_BINCL} and @code{C_EINCL} do not nest.
A @code{N_SLINE} symbol represents the start of a source line. The
@var{desc} field contains the line number and the @var{value} field
contains the code address for the start of that source line.
contains the code address for the start of that source line. On most
machines the address is absolute; for Sun's stabs-in-elf, it is relative
to the function in which the @code{N_SLINE} symbol occurs.
GNU documents @code{N_DSLINE} and @code{N_BSLINE} symbols for line
numbers in the data or bss segments, respectively. They are identical
@ -556,48 +558,26 @@ followed by line 50 of our sample assembly output, which has this form:
@node Block Structure
@section Block Structure
@table @strong
@item Directive:
@code{.stabn}
@item Types:
@code{N_LBRAC}, @code{N_RBRAC}
@end table
The program's block structure is represented by the @code{N_LBRAC} (left
brace) and the @code{N_RBRAC} (right brace) stab types. The following code
range, which is the body of @code{main}, is labeled with @samp{LBB2:} at the
beginning and @samp{LBE2:} at the end.
@example
37 LBB2:
38 sethi %hi(LC0),%o1
39 or %o1,%lo(LC0),%o0
40 call _printf,0
41 nop
42 .stabn 68,0,6,LM3
43 LM3:
44 LBE2:
@end example
brace) and the @code{N_RBRAC} (right brace) stab types. The variables
defined inside a block preceded the @code{N_LBRAC} symbol for most
compilers, including GCC. Other compilers, such as the Convex, Acorn
RISC machine, and Sun acc compilers, put the variables after the
@code{N_LBRAC} symbol. The values of the @code{N_LBRAC} and
@code{N_RBRAC} symbols are the start and end addresses of the code of
the block, respectively. For most machines, they are relative to the
starting address of this source file. For the Gould NP1, they are
absolute. For Sun's stabs-in-elf, they are relative to the function in
which they occur.
The @code{N_LBRAC} and @code{N_RBRAC} stabs that describe the block
scope of the procedure are located after the @code{N_FUNC} stab that
represents the procedure itself. The @code{N_LBRAC} uses the
@code{LBB2} label as the code address in its value field, and the
@code{N_RBRAC} uses @code{LBE2}.
scope of a procedure are located after the @code{N_FUN} stab that
represents the procedure itself.
@example
50 .stabs "main:F1",36,0,0,_main
@end example
@example
.stabn N_LBRAC, NIL, NIL, @var{left-brace-address}
.stabn N_RBRAC, NIL, NIL, @var{right-brace-address}
@end example
@example
51 .stabn 192,0,0,LBB2
52 .stabn 224,0,0,LBE2
@end example
Sun documents the @code{desc} field of @code{N_LBRAC} and
@code{N_RBRAC} symbols as containing the nesting level of the block.
However, dbx seems not to care, and GCC just always set @code{desc} to
zero.
@node Constants
@chapter Constants
@ -3092,7 +3072,7 @@ Automatic var in the stack or type definition, @xref{N_LSYM}, @xref{Typedefs}.
Beginning of an include file (Sun only), @xref{Source Files}.
@item 0x84 N_SOL
Name of sub-source (#include) file., @xref{Source Files}.
Name of include file, @xref{Source Files}.
@item 0xa0 N_PSYM
Parameter variable, @xref{Parameters}.
@ -3104,7 +3084,7 @@ End of an include file, @xref{Source Files}.
Alternate entry point, @xref{N_ENTRY}.
@item 0xc0 N_LBRAC
Beginning of a lexical block, @xref{N_LBRAC}.
Beginning of a lexical block, @xref{Block Structure}.
@item 0xc2 N_EXCL
Place holder for a deleted include file, @xref{Source Files}.
@ -3113,7 +3093,7 @@ Place holder for a deleted include file, @xref{Source Files}.
Modula2 scope information (Sun linker), @xref{N_SCOPE}.
@item 0xe0 N_RBRAC
End of a lexical block, @xref{N_RBRAC}.
End of a lexical block, @xref{Block Structure}.
@item 0xe2 N_BCOMM
Begin named common block, @xref{N_BCOMM}.
@ -3428,9 +3408,7 @@ Finally, any further information.
* N_SSYM:: Structure or union element
* N_LSYM:: Automatic variable
* N_ENTRY:: Alternate entry point
* N_LBRAC:: Beginning of lexical block
* N_SCOPE:: Modula2 scope information (Sun only)
* N_RBRAC:: End of lexical block
* N_BCOMM:: Begin named common block
* N_ECOMM:: End named common block
* N_ECOML:: End common
@ -3677,40 +3655,12 @@ Alternate entry point.
Value is its address.
<<?>>
@node N_LBRAC
@section 192 - 0xc0 - N_LBRAC
Beginning of a lexical block (left brace). The variable defined
inside the block precede the N_LBRAC symbol. Or can they follow as
well as long as a new N_FUNC was not encountered. <<?>>
@display
.stabn N_LBRAC, NIL, NIL, value
@end display
@example
value -> code address of block start.
@end example
@node N_SCOPE
@section 196 - 0xc4 - N_SCOPE
Modula2 scope information (Sun linker)
<<?>>
@node N_RBRAC
@section 224 - 0xe0 - N_RBRAC
End of a lexical block (right brace)
@display
.stabn N_RBRAC, NIL, NIL, value
@end display
@example
value -> code address of the end of the block.
@end example
@node N_BCOMM
@section 226 - 0xe2 - N_BCOMM
@ -3897,11 +3847,6 @@ N_LENG unknown
GNU C stabs define *all* types, file or procedure scope, as
N_LSYM. Sun doc talks about using N_GSYM too.
@item
Stabs describing block scopes, N_LBRAC and N_RBRAC are supposed to
contain the nesting level of the block in the desc field, re Sun doc.
GNU stabs always have 0 in that field. dbx seems not to care.
@item
Sun C stabs use type number pairs in the format (a,b) where a is a
number starting with 1 and incremented for each sub-source file in the