Patchwork [RFA,jit] initialize input_location

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Submitter Tom Tromey
Date March 24, 2014, 11:29 a.m.
Message ID <874n2nx2b2.fsf@fleche.redhat.com>
Download mbox | patch
Permalink /patch/333016/
State New
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Comments

Tom Tromey - March 24, 2014, 11:29 a.m.
>>>>> "Dave" == David Malcolm <dmalcolm-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> writes:

Dave> Given this declaration in input.c:
Dave>   location_t input_location;
Dave> then assigning 0 is a faithful way of resetting it to its initial state.

Dave> That said, "0" feels like a magic number.  Would it better to assign
Dave> UNKNOWN_LOCATION to it? which is 0, c.f. input.h:

Dave>   #define UNKNOWN_LOCATION ((source_location) 0)

Dave> If so, perhaps the declaration in input.c should gain an initializer to
Dave> the same value?  (shouldn't affect the code, since it's 0 either way,
Dave> but perhaps it's more readable?)

Sounds reasonable to me.
How about the appended?

Tom

commit 79ce51eaf41ce7b0e90407245b7cad33ada6887b
Author: Tom Tromey <tromey@redhat.com>
Date:   Thu Mar 20 08:51:25 2014 -0600

    initialize input_location
    
    This patch initializes input_location at the same spot where the line
    table is initialized.  Without this, it's possible to crash when
    emitting a diagnostic in a reinvocation of the compiler, because
    input_location refers to a location that is no longer valid.
David Malcolm - March 24, 2014, 6:15 p.m.
On Mon, 2014-03-24 at 05:29 -0600, Tom Tromey wrote:
> 
> >>>>> "Dave" == David Malcolm <dmalcolm-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> writes:
> 
> Dave> Given this declaration in input.c:
> Dave>   location_t input_location;
> Dave> then assigning 0 is a faithful way of resetting it to its initial state.
> 
> Dave> That said, "0" feels like a magic number.  Would it better to assign
> Dave> UNKNOWN_LOCATION to it? which is 0, c.f. input.h:
> 
> Dave>   #define UNKNOWN_LOCATION ((source_location) 0)
> 
> Dave> If so, perhaps the declaration in input.c should gain an initializer to
> Dave> the same value?  (shouldn't affect the code, since it's 0 either way,
> Dave> but perhaps it's more readable?)
> 
> Sounds reasonable to me.
> How about the appended?
> 
> Tom
> 
> commit 79ce51eaf41ce7b0e90407245b7cad33ada6887b
> Author: Tom Tromey <tromey@redhat.com>
> Date:   Thu Mar 20 08:51:25 2014 -0600
> 
>     initialize input_location
>     
>     This patch initializes input_location at the same spot where the line
>     table is initialized.  Without this, it's possible to crash when
>     emitting a diagnostic in a reinvocation of the compiler, because
>     input_location refers to a location that is no longer valid.
> 
> diff --git a/gcc/ChangeLog.jit b/gcc/ChangeLog.jit
> index ee1df88..5145cf9 100644
> --- a/gcc/ChangeLog.jit
> +++ b/gcc/ChangeLog.jit
> @@ -1,3 +1,8 @@
> +2014-03-24  Tom Tromey  <tromey@redhat.com>
> +
> +	* toplev.c (general_init): Initialize input_location.
> +	* input.c (input_location): Initialize to UNKNOWN_LOCATION.
> +
>  2014-03-19  Tom Tromey  <tromey@redhat.com>
>  
>  	* timevar.h (auto_timevar): New class.
> diff --git a/gcc/input.c b/gcc/input.c
> index a141a92..90a708c 100644
> --- a/gcc/input.c
> +++ b/gcc/input.c
> @@ -1,5 +1,5 @@
>  /* Data and functions related to line maps and input files.
> -   Copyright (C) 2004-2013 Free Software Foundation, Inc.
> +   Copyright (C) 2004-2014 Free Software Foundation, Inc.
>  
>  This file is part of GCC.
>  
> @@ -25,7 +25,7 @@ along with GCC; see the file COPYING3.  If not see
>  
>  /* Current position in real source file.  */
>  
> -location_t input_location;
> +location_t input_location = UNKNOWN_LOCATION;
>  
>  struct line_maps *line_table;
>  
> diff --git a/gcc/toplev.c b/gcc/toplev.c
> index b257ab2..54a884e 100644
> --- a/gcc/toplev.c
> +++ b/gcc/toplev.c
> @@ -1161,6 +1161,7 @@ general_init (const char *argv0)
>       table.  */
>    init_ggc ();
>    init_stringpool ();
> +  input_location = UNKNOWN_LOCATION;
>    line_table = ggc_alloc_line_maps ();
>    linemap_init (line_table);
>    line_table->reallocator = realloc_for_line_map;


Thanks.  Feel free to push this to the dmalcolm/jit branch.

Patch

diff --git a/gcc/ChangeLog.jit b/gcc/ChangeLog.jit
index ee1df88..5145cf9 100644
--- a/gcc/ChangeLog.jit
+++ b/gcc/ChangeLog.jit
@@ -1,3 +1,8 @@ 
+2014-03-24  Tom Tromey  <tromey@redhat.com>
+
+	* toplev.c (general_init): Initialize input_location.
+	* input.c (input_location): Initialize to UNKNOWN_LOCATION.
+
 2014-03-19  Tom Tromey  <tromey@redhat.com>
 
 	* timevar.h (auto_timevar): New class.
diff --git a/gcc/input.c b/gcc/input.c
index a141a92..90a708c 100644
--- a/gcc/input.c
+++ b/gcc/input.c
@@ -1,5 +1,5 @@ 
 /* Data and functions related to line maps and input files.
-   Copyright (C) 2004-2013 Free Software Foundation, Inc.
+   Copyright (C) 2004-2014 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -25,7 +25,7 @@  along with GCC; see the file COPYING3.  If not see
 
 /* Current position in real source file.  */
 
-location_t input_location;
+location_t input_location = UNKNOWN_LOCATION;
 
 struct line_maps *line_table;
 
diff --git a/gcc/toplev.c b/gcc/toplev.c
index b257ab2..54a884e 100644
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -1161,6 +1161,7 @@  general_init (const char *argv0)
      table.  */
   init_ggc ();
   init_stringpool ();
+  input_location = UNKNOWN_LOCATION;
   line_table = ggc_alloc_line_maps ();
   linemap_init (line_table);
   line_table->reallocator = realloc_for_line_map;