RE: [patch] Shorten Windows path

[Joey Ye]

Ian, thanks for your comments. Please find answers and new version below:

> -----Original Message-----
> From: Ian Lance Taylor [mailto:i...@google.com]
> Sent: 25 March 2014 21:09
> To: Joey Ye
> Cc: gcc-patches
> Subject: Re: [patch] Shorten Windows path
> 
> On Tue, Mar 25, 2014 at 1:58 AM, Joey Ye <joey...@arm.com> wrote:
> > Ping
> 
> This code looks different on mainline.
> 
> Writing "if ( do_canonical )" is not GCC style.
Fixed
> 
> This patch does not respect the configure option --disable-canonical-system-
> headers.
Solved by put is under the control of default ENABLE_CANONICAL_SYSTEM_HEADERS
> 
> Also I personally don't actually know what the consequences would be.
> Are there any downsides to canonicalizing header names?
Since 4.8 system headers are by default canonicalized. This version only 
additionally canonical non-system headers. I can't think of any downsides.

> 
> Ian

ChangeLog.libcpp:

    * files.c (find_file_in_dir): Always try to shorten for DOS non-system 
headers.
    * init.c (ENABLE_CANONICAL_SYSTEM_HEADERS): Default enabled for DOS.

diff --git a/libcpp/files.c b/libcpp/files.c
index 7e88778..ad68682 100644
--- a/libcpp/files.c
+++ b/libcpp/files.c
@@ -387,8 +387,14 @@ find_file_in_dir (cpp_reader *pfile, _cpp_file *file, bool 
*invalid_pch)
       char *copy;
       void **pp;
 
-      /* We try to canonicalize system headers.  */
-      if (CPP_OPTION (pfile, canonical_system_headers) && file->dir->sysp)
+      /* We try to canonicalize system headers.  For DOS based file
+       * system, we always try to shorten non-system headers, as DOS
+       * has a tighter constraint on max path length.  */
+      if (CPP_OPTION (pfile, canonical_system_headers) && file->dir->sysp
+#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+         || !file->dir->sysp
+#endif
+        )
        {
          char * canonical_path = maybe_shorter_path (path);
          if (canonical_path)
diff --git a/libcpp/init.c b/libcpp/init.c
index f10413a..b809515 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -27,8 +27,12 @@ along with this program; see the file COPYING3.  If not see
 #include "filenames.h"
 
 #ifndef ENABLE_CANONICAL_SYSTEM_HEADERS
+#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+#define ENABLE_CANONICAL_SYSTEM_HEADERS 1
+#else
 #define ENABLE_CANONICAL_SYSTEM_HEADERS 0
 #endif
+#endif
 
 static void init_library (void);
 static void mark_named_operators (cpp_reader *, int);