Re: [PATCH 2/2] Handle Windows drives in auto-load script paths

[Simon Marchi <simark@simark.ca>]

Hi Hannes,

On 2020-05-29 11:08 a.m., Hannes Domani via Gdb-patches wrote:
> Fixes this testsuite fail on Windows:
> FAIL: gdb.base/auto-load.exp: print $script_loaded
>
> Converts the debugfile path from c:/dir/file to /c/dir/file, so it can be
> appended to the auto-load path.
>
> gdb/ChangeLog:
>
> 2020-05-29  Hannes Domani  <ssbssa@yahoo.de>
>
> 	* auto-load.c (auto_load_objfile_script_1): Convert drive part
> 	of debugfile path on Windows.
>
> gdb/doc/ChangeLog:
>
> 2020-05-29  Hannes Domani  <ssbssa@yahoo.de>
>
> 	* gdb.texinfo: Document Windows drive conversion of
> 	'set auto-load scripts-directory'.
> ---
> v2:
> - Document Windows drive conversion of 'set auto-load scripts-directory'.
> ---
>  gdb/auto-load.c     | 7 +++++++
>  gdb/doc/gdb.texinfo | 4 ++++
>  2 files changed, 11 insertions(+)
>
> diff --git a/gdb/auto-load.c b/gdb/auto-load.c
> index 99bd96b971..88221d9f3d 100644
> --- a/gdb/auto-load.c
> +++ b/gdb/auto-load.c
> @@ -784,6 +784,13 @@ auto_load_objfile_script_1 (struct objfile *objfile, const char *realname,
>  					  "scripts-directory' path \"%s\".\n"),
>  			    auto_load_dir);
>
> +      /* Convert Windows debugfile path from c:/dir/file to /c/dir/file.  */
> +      if (HAS_DRIVE_SPEC (debugfile))
> +	{
> +	  debugfile_holder = STRIP_DRIVE_SPEC (debugfile);

I looked at this patch a bit before realizing it is already merged.  I
was going to make a comment about the line above, so I made it a patch
instead, WDYT?


From 602e996b26d592ecda500ed64adafac30e0e9ce7 Mon Sep 17 00:00:00 2001
From: Simon Marchi <simon.marchi@polymtl.ca>
Date: Sun, 4 Oct 2020 22:00:17 -0400
Subject: [PATCH] gdb: avoid unnecessary string copy in
 auto_load_objfile_script_1

Assigning the result of STRIP_DRIVE_SPEC to an std::string creates an
unnecessary copy of the string.  STRIP_DRIVE_SPEC is defined as:

  #define STRIP_DRIVE_SPEC(f) ((f) + 2)

So if it is passed a "const char *", it returns a "const char *".  We
could use a "const char *" intermediary variable instead of an
std::string, or (as implemented in this patch) just use it directly in
the concatenation right after.

gdb/ChangeLog:

	* auto-load.c (auto_load_objfile_script_1): Don't use
	debugfile_holder as temporary variable when stripping drive
	letter.

Change-Id: If2ccc7a156b22100754d9cdf6778ac7eeb93da4c
---
 gdb/auto-load.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/gdb/auto-load.c b/gdb/auto-load.c
index 9a51d2f3dc6c..43d007ca5b03 100644
--- a/gdb/auto-load.c
+++ b/gdb/auto-load.c
@@ -777,10 +777,8 @@ auto_load_objfile_script_1 (struct objfile *objfile, const char *realname,

       /* Convert Windows file name from c:/dir/file to /c/dir/file.  */
       if (HAS_DRIVE_SPEC (debugfile))
-	{
-	  debugfile_holder = STRIP_DRIVE_SPEC (debugfile);
-	  filename = std::string("\\") + debugfile[0] + debugfile_holder;
-	}
+	filename = (std::string("\\") + debugfile[0]
+		    + STRIP_DRIVE_SPEC (debugfile));

       for (const gdb::unique_xmalloc_ptr<char> &dir : vec)
 	{
-- 
2.28.0