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BR3066383: Restore backward compatibility with token pasting

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It seems to be a bit long story for the reason if this bug. But
lets be verbose and describe all byte-to-byte. And it is all about
preprocessor code, in particular paste_tokens and expand_mmac_params.

Initially the problem (not the same but similar) was noticed and
fixed in commit ec88c1be. The problem reveals itself with code snippets
like

 | %macro m 1
 |  %push
 |      %define %$arg %1
 | %%top_%$arg:
 |      resb ($ - %%top_%$arg)
 |  %pop
 | %endmacro

So with commits ec88c1be, 51fd86e0, 1f6741fc, 985d880c we did expand
local single macro before processing tokens pasting unconditionally.

But then it being found that such approach breaks %assign directive.
The snippets like below didn't work

 | %macro m 1
 |  %push
 |      %assign %$arg %1
 |      %assign %$arg %1+%$arg
 |  %pop
 | %endmacro

So all these commits were reverted and we just stop pasting tokens
in paste_tokens() after TOK_PREPROC_ID (commit 20a94ad7). Unfortunately
this breaks %assign with compound preproc id

 | %macro m3 1
 |    %push
 |        %assign %$_uses 0
 |        %rep 4
 |            %assign %$_ur%$_uses %$_uses
 |            mov ecx, %$_ur%$_uses
 |            %assign %$_uses %$_uses+1
 |        %endrep
 |    %pop
 | %endmacro

To fix this bug we have to combine two approaches at once,
we should continue pasting after TOK_PREPROC_ID and expand
sequential TOK_PREPROC_IDs except first one.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
This commit is contained in:
Cyrill Gorcunov 2010-09-16 00:16:19 +04:00
parent 831222f244
commit 8bc8017df8
1 changed files with 30 additions and 0 deletions
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30
preproc.c
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@ -3660,6 +3660,7 @@ static bool paste_tokens(Token **head, bool handle_paste_tokens)
}
break;
case TOK_ID:
case TOK_PREPROC_ID:
case TOK_NUMBER:
case TOK_FLOAT:
{
@ -3972,6 +3973,35 @@ static Token *expand_mmac_params(Token * tline)
}
delete_Token(t);
changed = true;
} else if (tline->type == TOK_PREPROC_ID &&
tline->text[0] == '%' &&
tline->text[1] == '$' &&
!tok_type_(tline->next, TOK_WHITESPACE) &&
(tok_type_(tline->next, TOK_ID) ||
tok_type_(tline->next, TOK_PREPROC_ID) ||
tok_type_(tline->next, TOK_NUMBER) ||
tok_type_(tline->next, TOK_OTHER) ||
tok_type_(tline->next, TOK_FLOAT))) {
/*
* In a sake of backward compatibility we allow
* to expand local single macro that early before
* pasting token code have place
*
* NOTE: that new code MUST use %+ macro to obtain
* same result
*/
t = tline;
tline = tline->next;
tt = tokenize(t->text);
tt = expand_smacro(tt);
*tail = tt;
while (tt) {
tt->a.mac = NULL;
tail = &tt->next;
tt = tt->next;
}
delete_Token(t);
changed = true;
} else {
t = *tail = tline;
tline = tline->next;