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Diffstat (limited to 'gdb/doc/stabs.texinfo')
| -rw-r--r-- | gdb/doc/stabs.texinfo | 69 |
1 files changed, 29 insertions, 40 deletions
diff --git a/gdb/doc/stabs.texinfo b/gdb/doc/stabs.texinfo index 93a251a..d455e16 100644 --- a/gdb/doc/stabs.texinfo +++ b/gdb/doc/stabs.texinfo @@ -86,6 +86,7 @@ Appendixes: and GNU stabs in xcoff * Sun-differences:: Differences between GNU stabs and Sun native stabs +* Stabs-in-elf:: Stabs in an ELF file. @end menu @end ifinfo @@ -799,12 +800,13 @@ nesting is reflected in the nested bracketing stabs (@code{N_LBRAC}, @chapter Variables @menu -* Automatic variables:: locally scoped -* Global Variables:: -* Register variables:: -* Initialized statics:: -* Un-initialized statics:: -* Parameters:: +* Automatic variables:: Variables allocated on the stack. +* Global Variables:: Variables used by more than one source file. +* Common Blocks:: Variables statically allocated together. +* Register variables:: Variables in registers. +* Initialized statics:: Static variables with values. +* Un-initialized statics:: Static variables initialialized to 0. +* Parameters:: Passing variables to functions. @end menu @node Automatic variables @@ -929,9 +931,9 @@ number of the register where the variable data will be stored. The value is the register number. AIX defines a separate symbol descriptor @samp{d} for floating point -registers. This seems incredibly stupid---why not just just give -floating point registers different register numbers? I have not -verified whether the compiler actually uses @samp{d}. +registers. This seems unnecessary---why not just just give floating +point registers different register numbers? I have not verified whether +the compiler actually uses @samp{d}. If the register is explicitly allocated to a global variable, but not initialized, as in @@ -943,6 +945,20 @@ register int g_bar asm ("%g5"); the stab may be emitted at the end of the object file, with the other bss symbols. +@node Common Blocks +@section Common Blocks + +A common block is a statically allocated section of memory which can be +referred to by several source files. It may contain several variables. +I believe @sc{fortran} is the only language with this feature. A +@code{N_BCOMM} stab begins a common block and an @code{N_ECOMM} stab +ends it. The only thing which is significant about these two stabs is +their name, which can be used to look up a normal (non-debugging) symbol +which gives the address of the common block. Each variable in the +common block has a @code{N_ECOML} stab, whose value is the offset within +the common block of that variable. I'm not sure what symbol descriptor +is used for the @code{N_ECOML} stabs. + @node Initialized statics @section Initialized static variables @@ -3096,13 +3112,13 @@ Modula2 scope information (Sun linker), @xref{N_SCOPE}. End of a lexical block, @xref{Block Structure}. @item 0xe2 N_BCOMM -Begin named common block, @xref{N_BCOMM}. +Begin named common block, @xref{Common Blocks}. @item 0xe4 N_ECOMM -End named common block, @xref{N_ECOMM}. +End named common block, @xref{Common Blocks}. @item 0xe8 N_ECOML -End common (local name), @xref{N_ECOML}. +Member of a common block, @xref{Common Blocks}. @c FIXME: How does this really work? Move it to main body of document. @item 0xea N_WITH @@ -3409,9 +3425,6 @@ Finally, any further information. * N_LSYM:: Automatic variable * N_ENTRY:: Alternate entry point * N_SCOPE:: Modula2 scope information (Sun only) -* N_BCOMM:: Begin named common block -* N_ECOMM:: End named common block -* N_ECOML:: End common * Gould:: non-base register symbols used on Gould systems * N_LENG:: Length of preceding entry @end menu @@ -3661,30 +3674,6 @@ Value is its address. Modula2 scope information (Sun linker) <<?>> -@node N_BCOMM -@section 226 - 0xe2 - N_BCOMM - -Begin named common block. - -Only the name is significant. -<<?>> - -@node N_ECOMM -@section 228 - 0xe4 - N_ECOMM - -End named common block. - -Only the name is significant and it should match the N_BCOMM -<<?>> - -@node N_ECOML -@section 232 - 0xe8 - N_ECOML - -End common (local name) - -value is address. -<<?>> - @node Gould @section Non-base registers on Gould systems @@ -3855,7 +3844,7 @@ new type defined in the compilation. GNU C stabs use the type number alone, with no source file number. @end itemize -@node stabs-in-elf +@node Stabs-in-elf @appendix Using stabs with the ELF object file format. The ELF object file format allows tools to create object files with custom |