llvm dev - Aug 2004 - [LLVMdev] tblgen: Assertion failed: "Buffer[Length-1] == '"'", file FileLexer.l, line 114

Hi

I've been investigating which characters that cause troubles:

Length = 23
WhatsInBuffer=include "../Target.td"
assert=false
tblgen: Assertion failed: "Buffer[Length-1] == '"'", file
FileLexer.l, line
128
idx	hex	char
0	69	i
1	6E	n
2	63	c
3	6C	l
4	75	u
5	64	d
6	65	e
7	20
8	22	"
9	2E	.
10	2E	.
11	2F	/
12	54	T
13	61	a
14	72	r
15	67	g
16	65	e
17	74	t
18	2E	.
19	74	t
20	64	d
21	22	"
22	D

I can't see what's wrong here... Other than the " character at the
end of
the include statement, which the assertion is complaining about.

/Henrik
>From: Chris Lattner <sabre at nondot.org>
>Date: Wed, 18 Aug 2004 00:39:31 -0500 (CDT)
>
>On Tue, 17 Aug 2004, Misha Brukman wrote:
>
> > On Tue, Aug 17, 2004 at 09:39:23PM -0500, Chris Lattner wrote:
> > > > The next problem, on my system (Interix - you remember -
Hey, some
> > > > LLVM program is working :O ), is however, that it cannot
find the
> > > > ../Target.td file. At the moment I see some more bugs luring
ahead
> > > > in the TableGen code.  More on that later.
> > >
> > > I'm sure this is because you hacked the assertion, but
didn't fix the
> > > problem.  The question is: why is an extra char being included at
the
> > > end of the buffer?
> >
> > Does Windows-style double-char line terminator have anything to do
with
> > it?
>
>I thought about that, but no, no newlines of any sort are involved.
>
>-Chris
>
>--
>http://llvm.org/
>http://nondot.org/sabre/
>
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On Thu, Aug 19, 2004 at 01:04:55AM +0200, Henrik Bach
wrote:
> I've been investigating which characters that cause troubles:
> 
> Length = 23
> WhatsInBuffer=include "../Target.td"
> assert=false
> tblgen: Assertion failed: "Buffer[Length-1] == '"'",
file FileLexer.l, line
> 128
> idx	hex	char
> 0	69	i
> 1	6E	n
> 2	63	c
> 3	6C	l
> 4	75	u
> 5	64	d
> 6	65	e
> 7	20
> 8	22	"
> 9	2E	.
> 10	2E	.
> 11	2F	/
> 12	54	T
> 13	61	a
> 14	72	r
> 15	67	g
> 16	65	e
> 17	74	t
> 18	2E	.
> 19	74	t
> 20	64	d
> 21	22	"
> 22	D
> 
> I can't see what's wrong here... Other than the " character at
the end
> of the include statement, which the assertion is complaining about.
What's wrong is the 'D' hex character at the end of the include line
becoming part of the parsed string.  'D' is \013 which is carriage
return.  It is whitespace and shouldn't be in the parsed string.

Since Length = 23, it expects Buffer[22] == ", but instead it's \013.
That's an error, because Length should really be 22, and Buffer[21]
really is the character ".

So, the lexer is confused about what your whitespace is.  However,
llvm/utils/TableGen/FileLexer.l includes the following line:

[ \t\n\r]+     { /* Ignore whitespace */ }

which covers carriage returns (\r), so I am not sure *HOW* Length is set
to 23, but it *IS* the problem.  Unfortunately, we do not have access to
Interix to replicate this problem.

-- 
Misha Brukman :: http://misha.brukman.net :: http://llvm.cs.uiuc.edu