RFC: example fix to pr 2360

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

To make things more concrete to what I was refering to in
http://sourceware.org/ml/gdb/2007-11/msg00138.html I've filed pr 2360,
and attached is an example fix.

I'm not sufficiently happy with it that I'd submit it RFA, but that's
mostly because of perceived objections to the use of xfullpath.  Maybe
the thing to do is write a canonicalizer like what is done in
cli-cmds.c:cd_command (and presumably move it to a more generic
place).

Suggestions?

2007-11-15  Doug Evans  <dje@google.com>

	Fix PR 2360.
	* buildsym.h (struct subfile): New member `comparable_name'.
	* buildsym.c (start_subfile): Record comparable_name, use it when
	comparing new subfiles.
	(end_symtab): Free comparable_name.
	(canonicalize_subfile_path): New fn.

	* gdb.base/hashline1.exp: New file.
	* gdb.base/hashline2.exp: New file.
	* gdb.base/hashline3.exp: New file.

Index: buildsym.h
===================================================================
RCS file: /cvs/src/src/gdb/buildsym.h,v
retrieving revision 1.18
diff -u -p -r1.18 buildsym.h
--- buildsym.h	15 Nov 2007 22:54:22 -0000	1.18
+++ buildsym.h	15 Nov 2007 23:37:11 -0000
@@ -63,6 +63,7 @@ struct subfile
     struct subfile *next;
     char *name;
     char *dirname;
+    char *comparable_name;
     struct linetable *line_vector;
     int line_vector_length;
     enum language language;
Index: buildsym.c
===================================================================
RCS file: /cvs/src/src/gdb/buildsym.c,v
retrieving revision 1.57
diff -u -p -r1.57 buildsym.c
--- buildsym.c	15 Nov 2007 22:54:22 -0000	1.57
+++ buildsym.c	15 Nov 2007 23:37:11 -0000
@@ -68,6 +68,7 @@ static struct pending *free_pendings;
 
 static int have_line_numbers;
 
+static char *canonicalize_subfile_path (const char *path);
 static int compare_line_numbers (const void *ln1p, const void *ln2p);
 
 
@@ -517,33 +518,31 @@ void
 start_subfile (char *name, char *dirname)
 {
   struct subfile *subfile;
+  char *comparable_name;
+
+  /* Create a version of name that can be used to match different spellings.
+     PR 2360 */
+  {
+    char *p = name;
+    if (! IS_ABSOLUTE_PATH (name)
+	&& dirname != NULL)
+      p = concat (dirname, SLASH_STRING, name, NULL);
+    comparable_name = canonicalize_subfile_path (p);
+    if (p != name)
+      xfree (p);
+  }
 
   /* 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;
-
-      if (FILENAME_CMP (subfile_name, name) == 0)
+      if (FILENAME_CMP (subfile->comparable_name, comparable_name) == 0)
 	{
 	  current_subfile = subfile;
-	  if (subfile_name != subfile->name)
-	    xfree (subfile_name);
+	  xfree (comparable_name);
 	  return;
 	}
-      if (subfile_name != subfile->name)
-	xfree (subfile_name);
     }
 
   /* This subfile is not known.  Add an entry for it. Make an entry
@@ -560,6 +559,7 @@ start_subfile (char *name, char *dirname
   subfile->name = (name == NULL) ? NULL : savestring (name, strlen (name));
   subfile->dirname =
     (dirname == NULL) ? NULL : savestring (dirname, strlen (dirname));
+  subfile->comparable_name = comparable_name;
 
   /* Initialize line-number recording for this subfile.  */
   subfile->line_vector = NULL;
@@ -615,6 +615,16 @@ start_subfile (char *name, char *dirname
     }
 }
 
+/* Subroutine of start_subfile to canonicalize a path for comparison purposes.
+   Here we care that multiple spellings of the same path map to the same
+   file.  Space for the result is allocated with malloc.  */
+
+static char *
+canonicalize_subfile_path (const char *path)
+{
+  return xfullpath (path);
+}
+
 /* 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
@@ -1039,6 +1049,10 @@ end_symtab (CORE_ADDR end_addr, struct o
 	{
 	  xfree ((void *) subfile->dirname);
 	}
+      if (subfile->comparable_name != NULL)
+	{
+	  xfree ((void *) subfile->comparable_name);
+	}
       if (subfile->line_vector != NULL)
 	{
 	  xfree ((void *) subfile->line_vector);
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	15 Nov 2007 23:37:11 -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 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 "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	15 Nov 2007 23:37:11 -0000
@@ -0,0 +1,56 @@
+# 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 "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	15 Nov 2007 23:37:11 -0000
@@ -0,0 +1,55 @@
+# 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 "break $srcfile:$bp_location" \
+    "Breakpoint.*at.* file .*$srcfile, line.*" \
+    "set breakpoint"