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Re: [rfa] linespec.c, part 1


Looks good. 
testsuite results are same, compiled with ,-Werror, right ?

Check it in.

Thanks
Elena


David Carlton writes:
 > This patch gets rid of the goto's and move some code into separate
 > functions 'symbol_found' and 'minsym_found'.  It's based on the
 > following observations (I'll do them for symbol_found, but it's the
 > same for both):
 > 
 > 1) The code after the label symbol_found: looks like this
 > 
 >   symbol_found:
 >     if (sym != NULL)
 >       {
 >         /* initialize values appropriately, and then either return
 >            values or signal an error.
 >       }
 > 
 >    So we can move the code inside the braces into a separate function
 >    symbol_found that returns a struct symtab_and_lines, turning this
 >    into:
 > 
 >   symbol_found:
 >     if (sym != NULL)
 >       return symbol_found (args);
 > 
 > 2) In all situations where there is a 'goto symbol_found', it is
 >    immediately preceded by a check that sym is non-NULL.  So the
 >    behavior of the program isn't changed by if we leave the gotos
 >    intact but further rewrite the above code as
 > 
 >     if (sym != NULL)
 >   symbol_found:
 >       return symbol_found (args);
 > 
 > 3) So, given that this is the case, we might as well replace each
 >    'goto symbol_found' by 'return symbol_found (args);'.
 > 
 > The patch gets a little weird to read towards the end: it would seem
 > that the algorithms that patch -u uses don't always work the best if
 > you're moving chunks of code around.  Sorry about that.
 > 
 > David Carlton
 > carlton@math.stanford.edu
 > 
 > 2002-11-07  David Carlton  <carlton@math.stanford.edu>
 > 
 > 	* linespec.c (symbol_found): New function.
 > 	(minsym_found): New function.
 > 	(decode_line_1): Separate out some code into separate functions.
 > 
 > Index: linespec.c
 > ===================================================================
 > RCS file: /cvs/src/src/gdb/linespec.c,v
 > retrieving revision 1.25
 > diff -u -p -r1.25 linespec.c
 > --- linespec.c	24 Oct 2002 21:02:53 -0000	1.25
 > +++ linespec.c	7 Nov 2002 21:08:18 -0000
 > @@ -53,6 +53,18 @@ static char *find_toplevel_char (char *s
 >  static struct symtabs_and_lines decode_line_2 (struct symbol *[],
 >  					       int, int, char ***);
 >  
 > +static struct
 > +symtabs_and_lines symbol_found (int funfirstline,
 > +				char ***canonical,
 > +				char *copy,
 > +				struct symbol *sym,
 > +				struct symtab *s,
 > +				struct symtab *sym_symtab);
 > +
 > +static struct
 > +symtabs_and_lines minsym_found (int funfirstline,
 > +				struct minimal_symbol *msymbol);
 > +
 >  /* Helper functions. */
 >  
 >  /* Issue a helpful hint on using the command completion feature on
 > @@ -910,16 +922,9 @@ decode_line_1 (char **argptr, int funfir
 >  	  /* Look up entire name */
 >  	  sym = lookup_symbol (copy, 0, VAR_NAMESPACE, 0, &sym_symtab);
 >  	  s = (struct symtab *) 0;
 > -	  /* Prepare to jump: restore the " if (condition)" so outer layers see it */
 > -	  /* Symbol was found --> jump to normal symbol processing.
 > -	     Code following "symbol_found" expects "copy" to have the
 > -	     symbol name, "sym" to have the symbol pointer, "s" to be
 > -	     a specified file's symtab, and sym_symtab to be the symbol's
 > -	     symtab. */
 > -	  /* By jumping there we avoid falling through the FILE:LINE and
 > -	     FILE:FUNC processing stuff below */
 >  	  if (sym)
 > -	    goto symbol_found;
 > +	    return symbol_found (funfirstline, canonical, copy, sym,
 > +				 NULL, sym_symtab);
 >  
 >  	  /* Couldn't find any interpretation as classes/namespaces, so give up */
 >  	  /* The quotes are important if copy is empty.  */
 > @@ -985,12 +990,9 @@ decode_line_1 (char **argptr, int funfir
 >        sym = lookup_symbol (copy, 0, VAR_NAMESPACE, 0, &sym_symtab);
 >        if (sym)
 >  	{
 > -	  /* Yes, we have a symbol; jump to symbol processing */
 > -	  /* Code after symbol_found expects S, SYM_SYMTAB, SYM, 
 > -	     and COPY to be set correctly */
 >  	  *argptr = (*p == '\'') ? p + 1 : p;
 > -	  s = (struct symtab *) 0;
 > -	  goto symbol_found;
 > +	  return symbol_found (funfirstline, canonical, copy, sym,
 > +			       NULL, sym_symtab);
 >  	}
 >        /* Otherwise fall out from here and go to file/line spec
 >           processing, etc. */
 > @@ -1151,19 +1153,16 @@ decode_line_1 (char **argptr, int funfir
 >  	  sym = lookup_symbol (copy, 0, VAR_NAMESPACE, 0, &sym_symtab);
 >  	  s = (struct symtab *) 0;
 >  	  need_canonical = 1;
 > -	  /* Symbol was found --> jump to normal symbol processing.
 > -	     Code following "symbol_found" expects "copy" to have the
 > -	     symbol name, "sym" to have the symbol pointer, "s" to be
 > -	     a specified file's symtab, and sym_symtab to be the symbol's
 > -	     symtab. */
 > +	  /* Symbol was found --> jump to normal symbol processing.  */
 >  	  if (sym)
 > -	    goto symbol_found;
 > +	    return symbol_found (funfirstline, canonical, copy, sym,
 > +				 NULL, sym_symtab);
 >  
 >  	  /* If symbol was not found, look in minimal symbol tables */
 >  	  msymbol = lookup_minimal_symbol (copy, NULL, NULL);
 >  	  /* Min symbol was found --> jump to minsym processing. */
 >  	  if (msymbol)
 > -	    goto minimal_symbol_found;
 > +	    return minsym_found (funfirstline, msymbol);
 >  
 >  	  /* Not a user variable or function -- must be convenience variable */
 >  	  need_canonical = (s == 0) ? 1 : 0;
 > @@ -1196,84 +1195,92 @@ decode_line_1 (char **argptr, int funfir
 >  			: get_selected_block (0)),
 >  		       VAR_NAMESPACE, 0, &sym_symtab);
 >  
 > -symbol_found:			/* We also jump here from inside the C++ class/namespace 
 > -				   code on finding a symbol of the form "A::B::C" */
 > -
 >    if (sym != NULL)
 > -    {
 > -      if (SYMBOL_CLASS (sym) == LOC_BLOCK)
 > -	{
 > -	  /* Arg is the name of a function */
 > -	  values.sals = (struct symtab_and_line *)
 > -	    xmalloc (sizeof (struct symtab_and_line));
 > -	  values.sals[0] = find_function_start_sal (sym, funfirstline);
 > -	  values.nelts = 1;
 > +    return symbol_found (funfirstline, canonical, copy, sym, s, sym_symtab);
 >  
 > -	  /* Don't use the SYMBOL_LINE; if used at all it points to
 > -	     the line containing the parameters or thereabouts, not
 > -	     the first line of code.  */
 > +  msymbol = lookup_minimal_symbol (copy, NULL, NULL);
 >  
 > -	  /* We might need a canonical line spec if it is a static
 > -	     function.  */
 > -	  if (s == 0)
 > -	    {
 > -	      struct blockvector *bv = BLOCKVECTOR (sym_symtab);
 > -	      struct block *b = BLOCKVECTOR_BLOCK (bv, STATIC_BLOCK);
 > -	      if (lookup_block_symbol (b, copy, NULL, VAR_NAMESPACE) != NULL)
 > -		build_canonical_line_spec (values.sals, copy, canonical);
 > -	    }
 > -	  return values;
 > -	}
 > -      else
 > -	{
 > -	  if (funfirstline)
 > -	    error ("\"%s\" is not a function", copy);
 > -	  else if (SYMBOL_LINE (sym) != 0)
 > -	    {
 > -	      /* We know its line number.  */
 > -	      values.sals = (struct symtab_and_line *)
 > -		xmalloc (sizeof (struct symtab_and_line));
 > -	      values.nelts = 1;
 > -	      memset (&values.sals[0], 0, sizeof (values.sals[0]));
 > -	      values.sals[0].symtab = sym_symtab;
 > -	      values.sals[0].line = SYMBOL_LINE (sym);
 > -	      return values;
 > -	    }
 > -	  else
 > -	    /* This can happen if it is compiled with a compiler which doesn't
 > -	       put out line numbers for variables.  */
 > -	    /* FIXME: Shouldn't we just set .line and .symtab to zero
 > -	       and return?  For example, "info line foo" could print
 > -	       the address.  */
 > -	    error ("Line number not known for symbol \"%s\"", copy);
 > -	}
 > -    }
 > +  if (msymbol != NULL)
 > +    return minsym_found (funfirstline, msymbol);
 >  
 > -  msymbol = lookup_minimal_symbol (copy, NULL, NULL);
 > +  if (!have_full_symbols () &&
 > +      !have_partial_symbols () && !have_minimal_symbols ())
 > +    error ("No symbol table is loaded.  Use the \"file\" command.");
 >  
 > -minimal_symbol_found:		/* We also jump here from the case for variables
 > -				   that begin with '$' */
 > +  error ("Function \"%s\" not defined.", copy);
 > +  return values;		/* for lint */
 > +}
 >  
 > -  if (msymbol != NULL)
 > +static struct symtabs_and_lines
 > +symbol_found (int funfirstline, char ***canonical, char *copy,
 > +	      struct symbol *sym, struct symtab *s,
 > +	      struct symtab *sym_symtab)
 > +{
 > +  struct symtabs_and_lines values;
 > +  
 > +  if (SYMBOL_CLASS (sym) == LOC_BLOCK)
 >      {
 > +      /* Arg is the name of a function */
 >        values.sals = (struct symtab_and_line *)
 >  	xmalloc (sizeof (struct symtab_and_line));
 > -      values.sals[0] = find_pc_sect_line (SYMBOL_VALUE_ADDRESS (msymbol),
 > -					  (struct sec *) 0, 0);
 > -      values.sals[0].section = SYMBOL_BFD_SECTION (msymbol);
 > -      if (funfirstline)
 > +      values.sals[0] = find_function_start_sal (sym, funfirstline);
 > +      values.nelts = 1;
 > +
 > +      /* Don't use the SYMBOL_LINE; if used at all it points to
 > +	 the line containing the parameters or thereabouts, not
 > +	 the first line of code.  */
 > +
 > +      /* We might need a canonical line spec if it is a static
 > +	 function.  */
 > +      if (s == 0)
 >  	{
 > -	  values.sals[0].pc += FUNCTION_START_OFFSET;
 > -	  values.sals[0].pc = SKIP_PROLOGUE (values.sals[0].pc);
 > +	  struct blockvector *bv = BLOCKVECTOR (sym_symtab);
 > +	  struct block *b = BLOCKVECTOR_BLOCK (bv, STATIC_BLOCK);
 > +	  if (lookup_block_symbol (b, copy, NULL, VAR_NAMESPACE) != NULL)
 > +	    build_canonical_line_spec (values.sals, copy, canonical);
 >  	}
 > -      values.nelts = 1;
 >        return values;
 >      }
 > +  else
 > +    {
 > +      if (funfirstline)
 > +	error ("\"%s\" is not a function", copy);
 > +      else if (SYMBOL_LINE (sym) != 0)
 > +	{
 > +	  /* We know its line number.  */
 > +	  values.sals = (struct symtab_and_line *)
 > +	    xmalloc (sizeof (struct symtab_and_line));
 > +	  values.nelts = 1;
 > +	  memset (&values.sals[0], 0, sizeof (values.sals[0]));
 > +	  values.sals[0].symtab = sym_symtab;
 > +	  values.sals[0].line = SYMBOL_LINE (sym);
 > +	  return values;
 > +	}
 > +      else
 > +	/* This can happen if it is compiled with a compiler which doesn't
 > +	   put out line numbers for variables.  */
 > +	/* FIXME: Shouldn't we just set .line and .symtab to zero
 > +	   and return?  For example, "info line foo" could print
 > +	   the address.  */
 > +	error ("Line number not known for symbol \"%s\"", copy);
 > +    }
 > +}
 >  
 > -  if (!have_full_symbols () &&
 > -      !have_partial_symbols () && !have_minimal_symbols ())
 > -    error ("No symbol table is loaded.  Use the \"file\" command.");
 > +static struct symtabs_and_lines
 > +minsym_found (int funfirstline, struct minimal_symbol *msymbol)
 > +{
 > +  struct symtabs_and_lines values;
 >  
 > -  error ("Function \"%s\" not defined.", copy);
 > -  return values;		/* for lint */
 > +  values.sals = (struct symtab_and_line *)
 > +    xmalloc (sizeof (struct symtab_and_line));
 > +  values.sals[0] = find_pc_sect_line (SYMBOL_VALUE_ADDRESS (msymbol),
 > +				      (struct sec *) 0, 0);
 > +  values.sals[0].section = SYMBOL_BFD_SECTION (msymbol);
 > +  if (funfirstline)
 > +    {
 > +      values.sals[0].pc += FUNCTION_START_OFFSET;
 > +      values.sals[0].pc = SKIP_PROLOGUE (values.sals[0].pc);
 > +    }
 > +  values.nelts = 1;
 > +  return values;
 >  }


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