Re: gdb_realpath: dealing with ./ and ../

["Doug Evans" <dje at google dot com>]

The use of #line in the testcases in the appended patch is
questionable, but as a data point the testcases fail without the patch
and pass with the patch.  These versions of the testcases have been
amended to use substitute-path.

ref: pr 2360
http://sourceware.org/ml/gdb/2007-11/msg00138.html
http://sourceware.org/ml/gdb-patches/2007-11/msg00314.html

Maybe #line + substitute-path fixup isn't supported.
Again, this patch is just a data point.

Note: This patch contains the rewrite_subfile_path suggestion of my
previous email.  I don't know whether it helps or hurts the case
you're trying to fix.

Index: buildsym.c
===================================================================
RCS file: /cvs/src/src/gdb/buildsym.c,v
retrieving revision 1.59
diff -u -p -u -p -r1.59 buildsym.c
--- buildsym.c	1 Jan 2008 22:53:09 -0000	1.59
+++ buildsym.c	4 Jan 2008 21:26:11 -0000
@@ -44,6 +44,7 @@
 #include "cp-support.h"
 #include "dictionary.h"
 #include "addrmap.h"
+#include "source.h"
 
 /* Ask buildsym.h to define the vars it normally declares `extern'.  */
 #define	EXTERN
@@ -86,6 +87,7 @@ static struct obstack pending_addrmap_ob
 static int pending_addrmap_interesting;
 
 
+static char *rewrite_subfile_path (char *name, char* dirname);
 static int compare_line_numbers (const void *ln1p, const void *ln2p);
 
 
@@ -574,6 +576,20 @@ make_blockvector (struct objfile *objfil
   return (blockvector);
 }
 
+
+/* Workaround for IS_ABSOLUTE_PATH issue. When gdb is configured for
+   *ix, and we are debugging binary cross-compiled on windows, the original
+   IS_ABSOLUTE_PATH will always return 0. This is not good.  */
+#undef IS_ABSOLUTE_PATH
+#undef IS_DIR_SEPARATOR
+
+#define IS_DIR_SEPARATOR(c)	((c) == '/' || (c) == '\\')
+/* Note that IS_ABSOLUTE_PATH accepts d:foo as well, although it is
+   only semi-absolute.  This is because the users of IS_ABSOLUTE_PATH
+   want to know whether to prepend the current working directory to
+   a file name, which should not be done with a name like d:foo.  */
+#define IS_ABSOLUTE_PATH(f)	(IS_DIR_SEPARATOR((f)[0]) || (((f)[0]) && ((f)[1] == ':')))
+
 /* Start recording information about source code that came from an
    included (or otherwise merged-in) source file with a different
    name.  NAME is the name of the file (cannot be NULL), DIRNAME is
@@ -583,35 +599,32 @@ void
 start_subfile (char *name, char *dirname)
 {
   struct subfile *subfile;
+  /* Rewritten NAME, typically an absolute path, that is used to detect
+     identical subfiles.  */
+  char *comparable_name;
+
+  comparable_name = rewrite_subfile_path (name, dirname);
 
   /* See if this subfile is already known as a subfile of the current
      main source file.  */
 
   for (subfile = subfiles; subfile; subfile = subfile->next)
     {
-      char *subfile_name;
-
-      /* If NAME is an absolute path, and this subfile is not, then
-	 attempt to create an absolute path to compare.  */
-      if (IS_ABSOLUTE_PATH (name)
-	  && !IS_ABSOLUTE_PATH (subfile->name)
-	  && subfile->dirname != NULL)
-	subfile_name = concat (subfile->dirname, SLASH_STRING,
-			       subfile->name, NULL);
-      else
-	subfile_name = subfile->name;
+      char *subfile_name = rewrite_subfile_path (subfile->name,
+						 subfile->dirname);
 
-      if (FILENAME_CMP (subfile_name, name) == 0)
+      if (FILENAME_CMP (subfile_name, comparable_name) == 0)
 	{
 	  current_subfile = subfile;
-	  if (subfile_name != subfile->name)
-	    xfree (subfile_name);
+	  xfree (comparable_name);
+	  xfree (subfile_name);
 	  return;
 	}
-      if (subfile_name != subfile->name)
-	xfree (subfile_name);
+      xfree (subfile_name);
     }
 
+  xfree (comparable_name);
+
   /* This subfile is not known.  Add an entry for it. Make an entry
      for this subfile in the list of all subfiles of the current main
      source file.  */
@@ -681,6 +694,34 @@ start_subfile (char *name, char *dirname
     }
 }
 
+/* Subroutine of start_subfile to simplify it.
+   Convert NAME, DIRNAME to a form that can be used to watch for
+   identical subfiles.
+   Space for the result is malloc'd, caller must free.  */
+
+static char *
+rewrite_subfile_path (char *name, char *dirname)
+{
+  char *p = name;
+  char *rwname;
+
+  if (! IS_ABSOLUTE_PATH (name)
+      && dirname != NULL)
+    p = concat (dirname, SLASH_STRING, name, NULL);
+
+  rwname = rewrite_source_path (p);
+
+  if (rwname != NULL)
+    {
+      if (p != name)
+	xfree (p);
+      return rwname;
+    }
+  if (p != name)
+    return p;
+  return xstrdup (name);
+}
+
 /* For stabs readers, the first N_SO symbol is assumed to be the
    source file name, and the subfile struct is initialized using that
    assumption.  If another N_SO symbol is later seen, immediately
Index: source.c
===================================================================
RCS file: /cvs/src/src/gdb/source.c,v
retrieving revision 1.83
diff -u -p -u -p -r1.83 source.c
--- source.c	1 Jan 2008 22:53:13 -0000	1.83
+++ source.c	4 Jan 2008 21:26:11 -0000
@@ -895,10 +895,12 @@ get_substitute_path_rule (const char *pa
    Return NULL if no substitution rule was specified by the user,
    or if no rule applied to the given PATH.  */
    
-static char *
+char *
 rewrite_source_path (const char *path)
 {
-  const struct substitute_path_rule *rule = get_substitute_path_rule (path);
+  const struct substitute_path_rule *rule = (path != NULL) ? 
+					get_substitute_path_rule (path):
+					NULL;
   char *new_path;
   int from_len;
   
@@ -999,10 +1001,11 @@ find_and_open_source (struct objfile *ob
 	  strcat (path + len, source_path + len + cdir_len);	/* After $cdir */
 	}
     }
-  else
+  
+  if (IS_ABSOLUTE_PATH (filename))
     {
-      /* If dirname is NULL, chances are the path is embedded in
-         the filename.  Try the source path substitution on it.  */
+      /* If filename is absolute path, try the source path 
+	 substitution on it.  */
       char *rewritten_filename = rewrite_source_path (filename);
 
       if (rewritten_filename != NULL)
Index: source.h
===================================================================
RCS file: /cvs/src/src/gdb/source.h,v
retrieving revision 1.9
diff -u -p -u -p -r1.9 source.h
--- source.h	1 Jan 2008 22:53:13 -0000	1.9
+++ source.h	4 Jan 2008 21:26:11 -0000
@@ -66,4 +66,14 @@ extern struct symtab_and_line set_curren
 
 /* Reset any information stored about a default file and line to print. */
 extern void clear_current_source_symtab_and_line (void);
+
+/* If the user specified a source path substitution rule that applies
+   to PATH, then apply it and return the new path.  This new path must
+   be deallocated afterwards.  
+   
+   Return NULL if no substitution rule was specified by the user,
+   or if no rule applied to the given PATH.  */
+   
+extern char *rewrite_source_path (const char *path);
+
 #endif
Index: testsuite/gdb.base/hashline1.exp
===================================================================
RCS file: testsuite/gdb.base/hashline1.exp
diff -N testsuite/gdb.base/hashline1.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.base/hashline1.exp	4 Jan 2008 21:26:18 -0000
@@ -0,0 +1,60 @@
+# Copyright 2007 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+# Test loading of line number information with absolute path in #line, bug 2360.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set prms_id 2360
+set bug_id 0
+
+# srcfile is in objdir because we need to machine generate it in order
+# to get correct the correct path in the #line directive.
+
+set testfile "hashline1"
+set srcfile "${testfile}.c"
+set binfile "${objdir}/${subdir}/${testfile}"
+
+set fd [open ${objdir}/${subdir}/${srcfile} w]
+puts $fd "#line 2 \"[pwd]/${subdir}/${srcfile}\""
+puts $fd "int main () { return 0; } /* set breakpoint here */"
+close $fd
+
+# The choice of path name for the source file is important in order to
+# trigger the bug.  Using ${objdir}/${subdir}/${srcfile} here won't trigger
+# the bug.
+if { [gdb_compile "./${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested hashline1.exp
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+set bp_location [gdb_get_line_number "set breakpoint here" ${objdir}/${subdir}/${srcfile}]
+
+# Try to set a breakpoint on the specified file location.
+
+gdb_test "set substitute-path [pwd]/. [pwd]" "" ""
+
+gdb_test "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line.*" \
+    "set breakpoint"
Index: testsuite/gdb.base/hashline2.exp
===================================================================
RCS file: testsuite/gdb.base/hashline2.exp
diff -N testsuite/gdb.base/hashline2.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.base/hashline2.exp	4 Jan 2008 21:26:18 -0000
@@ -0,0 +1,58 @@
+# Copyright 2007 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+# Test loading of line number information with an absolute path with extra
+# /'s in #line, bug 2360.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set prms_id 2360
+set bug_id 0
+
+# srcfile is in objdir because we need to machine generate it in order
+# to get correct the correct path in the #line directive.
+
+set testfile "hashline2"
+set srcfile "${testfile}.c"
+set binfile "${objdir}/${subdir}/${testfile}"
+
+set fd [open ${objdir}/${subdir}/${srcfile} w]
+puts $fd "#line 2 \"///[pwd]/${subdir}/${srcfile}\""
+puts $fd "int main () { return 0; } /* set breakpoint here */"
+close $fd
+
+if { [gdb_compile "${objdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested hashline1.exp
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+set bp_location [gdb_get_line_number "set breakpoint here" ${objdir}/${subdir}/${srcfile}]
+
+# Try to set a breakpoint on the specified file location.
+
+gdb_test "set substitute-path ///[pwd] [pwd]" "" ""
+
+gdb_test "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line.*" \
+    "set breakpoint"
Index: testsuite/gdb.base/hashline3.exp
===================================================================
RCS file: testsuite/gdb.base/hashline3.exp
diff -N testsuite/gdb.base/hashline3.exp
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ testsuite/gdb.base/hashline3.exp	4 Jan 2008 21:26:18 -0000
@@ -0,0 +1,57 @@
+# Copyright 2007 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# This file is part of the gdb testsuite.
+
+# Test loading of line number information with relative path in #line, bug 2360.
+
+if $tracelevel then {
+    strace $tracelevel
+}
+
+set prms_id 2360
+set bug_id 0
+
+# srcfile is in objdir because we need to machine generate it in order
+# to get correct the correct path in the #line directive.
+
+set testfile "hashline3"
+set srcfile "${testfile}.c"
+set binfile "${objdir}/${subdir}/${testfile}"
+
+set fd [open ${objdir}/${subdir}/${srcfile} w]
+puts $fd "#line 2 \"./${subdir}/${srcfile}\""
+puts $fd "int main () { return 0; } /* set breakpoint here */"
+close $fd
+
+if { [gdb_compile "${objdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
+    untested hashline1.exp
+    return -1
+}
+
+gdb_exit
+gdb_start
+gdb_reinitialize_dir $srcdir/$subdir
+gdb_load ${binfile}
+
+set bp_location [gdb_get_line_number "set breakpoint here" ${objdir}/${subdir}/${srcfile}]
+
+# Try to set a breakpoint on the specified file location.
+
+gdb_test "set substitute-path ${objdir}/. ${objdir}" "" ""
+
+gdb_test "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line.*" \
+    "set breakpoint"