BR3066383: Restore backward compatibility with token pasting
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>