Re: sparse ctags

[Josh Triplett <josh@freedesktop.org>]

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Josh Triplett wrote:
> On Tue, 2007-06-26 at 14:15 +0530, Aneesh Kumar wrote:
>> Is there a document how to use this ? Does this work on multiple files
>> ? Looking at the source i see it opening tags in truncate mode
> 
> No documentation, unfortunately.  The Sparse ctags doesn't take any
> options.  It should work on multiple files by simply giving all the
> files on one ctags command line, with something like:
> ctags $(find -name '*.c')
> 
> However, it seems to have some problems at the moment running on even
> *one* file:
> 
> $ ./ctags ctags.c
> unknown symbol const namespace:2 type:17
> 
> $ ./ctags validation/context.c
> unknown symbol const namespace:2 type:17
> 
> type 17 refers to SYM_KEYWORD, which seems consistent with "unknown
> symbol const", though I don't know why ctags would look at const as a
> symbol.

Looks like some enums grew new values and ctags didn't stay up to date.  I
think this patch fixes that particular problem:

diff --git a/ctags.c b/ctags.c
index f5b8fc7..63f59a5 100644
--- a/ctags.c
+++ b/ctags.c
@@ -111,6 +111,8 @@ static void examine_symbol(struct symbol *sym)
 		return;
 	if (sym->ident && sym->ident->reserved)
 		return;
+	if (sym->type == SYM_KEYWORD)
+		return;
 
 	add_tag(sym);
 	base = sym->ctype.base_type;
@@ -158,6 +160,8 @@ static void examine_namespace(struct symbol *sym)
 		return;
 
 	switch(sym->namespace) {
+	case NS_KEYWORD:
+		return;
 	case NS_LABEL:
 		sym->kind = 'l';
 		break;

With that patch, ctags successfully ran on individual files.  I then observed
some unusual symbols in the tags files:

add_dirafter    preprocessor    0;"     ^@      file:
add_include     preprocessor    0;"     ^@      file:
add_isystem     preprocessor    0;"     ^@      file:
define  preprocessor    0;"     ^@      file:
elif    preprocessor    0;"     ^@      file:
endif   preprocessor    0;"     ^@      file:
error   preprocessor    0;"     ^@      file:
ifdef   preprocessor    0;"     ^@      file:
ifndef  preprocessor    0;"     ^@      file:
include preprocessor    0;"     ^@      file:
include_next    preprocessor    0;"     ^@      file:
line    preprocessor    0;"     ^@      file:
nostdinc        preprocessor    0;"     ^@      file:
pragma  preprocessor    0;"     ^@      file:
split_include   preprocessor    0;"     ^@      file:
strong_define   preprocessor    0;"     ^@      file:
strong_undef    preprocessor    0;"     ^@      file:
undef   preprocessor    0;"     ^@      file:
warning preprocessor    0;"     ^@      file:
weak_define     preprocessor    0;"     ^@      file:

^@ here signifies a null.

After some further investigation, I think ctags really shouldn't look at
SYM_PREPROCESSOR or NS_PREPROCESSOR either.  I came up with the attached
patch, which I will apply soon unless someone shouts.  Chris?

This still doesn't fix running ctags on multiple files; ctags seems to get
confused in much the same way sparse does when run on multiple files: it spews
a pile of redefinition errors.

After we get ctags fixed up, clearly it needs some tests in the test suite so
this doesn't happen again.

- Josh Triplett

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From 3624a543e3884e2faa9980a2ecb0c10cda646671 Mon Sep 17 00:00:00 2001
From: Josh Triplett <josh@freedesktop.org>
Date: Mon, 6 Aug 2007 20:37:25 -0700
Subject: [PATCH] ctags: Handle some new namespaces and symbol types.

ctags didn't handle SYM_KEYWORD, SYM_PROCESSOR, or NS_KEYWORD, and didn't
handle NS_PREPROCESSOR correctly.

Signed-off-by: Josh Triplett <josh@freedesktop.org>
---
 ctags.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/ctags.c b/ctags.c
index f5b8fc7..7e129a6 100644
--- a/ctags.c
+++ b/ctags.c
@@ -111,6 +111,8 @@ static void examine_symbol(struct symbol *sym)
 		return;
 	if (sym->ident && sym->ident->reserved)
 		return;
+	if (sym->type == SYM_KEYWORD || sym->type == SYM_PREPROCESSOR)
+		return;
 
 	add_tag(sym);
 	base = sym->ctype.base_type;
@@ -158,11 +160,12 @@ static void examine_namespace(struct symbol *sym)
 		return;
 
 	switch(sym->namespace) {
+	case NS_KEYWORD:
+	case NS_PREPROCESSOR:
+		return;
 	case NS_LABEL:
 		sym->kind = 'l';
 		break;
-	case NS_PREPROCESSOR:
-		break;
 	case NS_MACRO:
 	case NS_UNDEF:
 		sym->kind = 'd';
-- 
1.5.2.4


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