[PATCH] Make Preprocessor::Lex non-recursive

[Eli Friedman]

On Wed, Sep 18, 2013 at 3:45 PM, Richard Smith <richard at metafoo.co.uk>wrote:

> On Wed, Sep 18, 2013 at 3:44 PM, Richard Smith <richard at metafoo.co.uk>wrote:
>
>> A modules-related change seems to have slipped into
>> lib/Frontend/CompilerInstance.cpp
>>
>
Ah, yes, thanks; fixed in my local copy.


>
>> The IsAtStartOfLine FIXME concerns me a little. Token.h says:
>>
>>     StartOfLine   = 0x01,  // At start of line or only after whitespace.
>>
>> ... which implies to me that the intent was that it be false if there's a
>> preceding EMPTY macro. I'm not sure if that's what the existing users of
>> the macro want, though.
>>
>
> Um, users of the flag.
>

The current users of the flag expect the current behavior, which ignores
empty macros.  The canonical example is PrintPreprocessedOutput, which uses
it to indicate whether it needs to insert a newline between two tokens, the
behavior being tested in test/Preprocessor/hash_line.c.  This patch doesn't
change our behavior here outside of the IDENTITY() case.  I'll update the
comment.

What happens if the Lex call in isNextPPTokenLParen returns false?
>>
>
Lex never returns false if we're lexing in raw mode.  I'll add an assertion
to that effect.

-Eli
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