freezing trace status

[Eric Blake]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

In working on frozen file status, I decided it was time to fix some of the
shortcomings, by tracing more state.  Here's a patch for master that
tracks trace status, both for single macros (whether defined or not at
time of freezing) and for debugmode (flag t affects global tracing status,
and other flags affect tracing output).

This patch doesn't address command-line parsing questions.  For example,
this now freezes that foo is traced, and that debugmode is aeq:

echo 'traceon(foo)define(foo,bar)' | m4 -F foo.m4f -d

But this invocation:

m4 -R foo.m4f --traceoff=foo -d-q

disables tracing of foo, but still uses aeq (and not ae) as the debugmode.
This is because -d is currently acted on during option parsing, then
frozen file is reloaded, then --traceon/--traceoff are used in their
location interleaved with input files.  I like the action of --traceon/-t
better, since both files and command line can override each other, merely
by choosing the correct order for listing the commands.  But interleaving
- -d with command-line files means that 'm4 file -dV' no longer turns on
debugging before parsing file, and this might break existing m4 clients
(for 2.0, that's probably okay, as long as it is documented in NEWS).  So
is it worth a followup patch that defers command-line action on -d to
match the behavior of -t?

Also, since branch-1.6 is a jump in version number, now is the time to
consider whether we should also make frozen files more powerful for 1.6 by
changing to frozen file format V2 (backporting portions of master's
current V2 such as allowing escape sequences and tracking tracing status),
then making the master branch use V3 (with additional directives such as M
for modules and 3-argument F for limiting a builtin load to a particular
module).

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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>From 63274fef7a86432e88938c6787b6e7d4deb4dbf2 Mon Sep 17 00:00:00 2001
From: Eric Blake <address@hidden>
Date: Sat, 17 May 2008 21:48:41 -0600
Subject: [PATCH] Allow freezing the trace status of macros.

* src/freeze.c (produce_symbol_dump): Let undefined traced macros
through.
(dump_symbol_CB): Also freeze trace state.
* tests/freeze.at (reloading traced macros): New test.
* doc/m4.texinfo (Using frozen files): Update documentation to
mention new state.
(Frozen file format 1): Improve synchronization with branch.
(Frozen file format 2): Reorder directives, and add `d', `t'.
* NEWS: Document this change.

Signed-off-by: Eric Blake <address@hidden>
---
 ChangeLog       |   13 +++
 NEWS            |   11 ++-
 doc/m4.texinfo  |  242 ++++++++++++++++++++++++++++++++++++++----------------
 src/freeze.c    |   85 +++++++++++++++++++-
 tests/freeze.at |   42 +++++++---
 5 files changed, 302 insertions(+), 91 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b7bd8f3..1210238 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2008-05-18  Eric Blake  <address@hidden>
+
+       Allow freezing the trace status of macros.
+       * src/freeze.c (produce_symbol_dump): Let undefined traced macros
+       through.
+       (dump_symbol_CB): Also freeze trace state.
+       * tests/freeze.at (reloading traced macros): New test.
+       * doc/m4.texinfo (Using frozen files): Update documentation to
+       mention new state.
+       (Frozen file format 1): Improve synchronization with branch.
+       (Frozen file format 2): Reorder directives, and add `d', `t'.
+       * NEWS: Document this change.
+
 2008-05-15  Eric Blake  <address@hidden>
 
        Fix frozen file regression in pushdef stacks from 2001-09-01.
diff --git a/NEWS b/NEWS
index ea0385b..6d2624d 100644
--- a/NEWS
+++ b/NEWS
@@ -195,11 +195,12 @@ promoted to 2.0.
 
 *** The syntax of frozen files format V2 has been improved to save
     additional state.  This includes the `R' directive for default regular
-    expression syntax.  Also, a V2 file can now be represented completely
-    in ASCII, thanks to escape sequences.  Unfortunately, files frozen by
-    M4 1.4q that contain \ in macros cannot be read by 1.9b, but since 1.4q
-    was not widely distributed, this is not expected to be much of an
-    issue, and comes with the territory of using a beta release.
+    expression syntax, the `t' directive for traced macros, and the `d'
+    directive for debug mode.  Also, a V2 file can now be represented
+    completely in ASCII, thanks to escape sequences.  Unfortunately, files
+    frozen by M4 1.4q cannot be read by 1.9b, but since 1.4q was not widely
+    distributed, this is not expected to be much of an issue, and comes
+    with the territory of using a beta release.
   - FIXME: format 2 still needs to catch more missing state; once 2.0 is
     released, any further changes would introduce format 3.
 
diff --git a/doc/m4.texinfo b/doc/m4.texinfo
index 8c4c237..6978714 100644
--- a/doc/m4.texinfo
+++ b/doc/m4.texinfo
@@ -8265,15 +8265,14 @@ $ @kbd{m4 -R file2.m4f -F file3.m4f file3.m4}
 $ @kbd{m4 -R file3.m4f file4.m4}
 @end example
 
address@hidden FIXME - merge the rest of this section.
-Some care is necessary because not every effort has been made for
-this to work in all cases.  In particular, the trace attribute of
-macros is not handled.
-Also, interactions for some options of @code{m4} being used in one call
-and not for the next, have not been fully analyzed yet.  On the other
-end, you may be confident that stacks of @code{pushdef}'ed definitions
-are handled correctly, so are @code{undefine}'d or renamed builtins,
-changed strings for quotes or comments.
+Some care is necessary because the frozen file does not save all state
+information.  Stacks of macro definitions via @code{pushdef} are
+accurately stored, along with all renamed or undefined builtins, as are
+the current syntax rules such as from @code{changequote}.  However, the
+value of @code{sysval} and text saved in @code{m4wrap} are not currently
+preserved.  Also, changing command line options between runs may cause
+unexpected behavior.  A future release of @acronym{GNU} M4 may improve
+on the quality of frozen files.
 
 When an @code{m4} run is to be frozen, the automatic undiversion
 which takes place at end of execution is inhibited.  Instead, all
@@ -8284,14 +8283,83 @@ A frozen file to be reloaded need not reside in the 
current directory.
 It is looked up the same way as an @code{include} file (@pxref{Search
 Path}).
 
+If the frozen file was generated with a newer version of @code{m4}, and
+contains directives that an older @code{m4} cannot parse, attempting to
+load the frozen file with option @option{-R} will cause @code{m4} to
+exit with status 63 to indicate version mismatch.
+
 @node Frozen file format 1
 @section Frozen file format 1
 
 @cindex frozen file format 1
 @cindex file format, frozen file version 1
-Wow - thanks for really reading the manual.  Report this as a bug if
-this text is not removed before a release.
-FIXME - split out the two formats into separate nodes.
+Frozen files are sharable across architectures.  It is safe to write
+a frozen file on one machine and read it on another, given that the
+second machine uses the same or newer version of @acronym{GNU} @code{m4}.
+It is conventional, but not required, to give a frozen file the suffix
+of @code{.m4f}.
+
+Older versions of @acronym{GNU} @code{m4} create frozen files with
+syntax version 1.  These files can be read by the current version, but
+are no longer produced.  Version 1 files are mostly text files, although
+any macros or diversions that contained nonprintable characters or long
+lines cause the resulting frozen file to do likewise, since there are no
+escape sequences.  The file can be edited to change the state that
address@hidden will start with.  It is composed of several directives, each
+starting with a single letter and ending with a newline (@key{NL}).
+Wherever a directive is expected, the character @samp{#} can be used
+instead to introduce a comment line; empty lines are also ignored if
+they are not part of an embedded string.
+
+In the following descriptions, each @var{len} refers to the length of a
+corresponding subsequent @var{str}.  Numbers are always expressed in
+decimal, and an omitted number defaults to 0.  The valid directives in
+version 1 are:
+
address@hidden @code
address@hidden V @var{number} @key{NL}
+Confirms the format of the file.  Version 1 is recognized when
address@hidden is 1.  This directive must be the first non-comment in the
+file, and may not appear more than once.
+
address@hidden C @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
+Uses @var{str1} and @var{str2} as the begin-comment and
+end-comment strings.  If omitted, then @samp{#} and @key{NL} are the
+comment delimiters.
+
address@hidden D @var{number}, @var{len} @key{NL} @var{str} @key{NL}
+Selects diversion @var{number}, making it current, then copy @var{str}
+in the current diversion.  @var{number} may be a negative number for a
+diversion that discards text.  To merely specify an active selection,
+use this command with an empty @var{str}.  With 0 as the diversion
address@hidden, @var{str} will be issued on standard output at reload
+time.  @acronym{GNU} @code{m4} will not produce the @samp{D} directive
+with non-zero length for diversion 0, but this can be done with manual
+edits.  This directive may appear more than once for the same diversion,
+in which case the diversion is the concatenation of the various uses.
+If omitted, then diversion 0 is current.
+
address@hidden F @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
+Defines, through @code{pushdef}, a definition for @var{str1} expanding
+to the function whose builtin name is @var{str2}.  If the builtin does
+not exist (for example, if the frozen file was produced by a copy of
address@hidden compiled with the now-abandoned @code{changeword} support),
+the reload is silent, but any subsequent use of the definition of
address@hidden will result in a warning.  This directive may appear more
+than once for the same name, and its order, along with @samp{T}, is
+important.  If omitted, you will have no access to any builtins.
+
address@hidden Q @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
+Uses @var{str1} and @var{str2} as the begin-quote and end-quote
+strings.  If omitted, then @samp{`} and @samp{'} are the quote
+delimiters.
+
address@hidden T @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
+Defines, though @code{pushdef}, a definition for @var{str1}
+expanding to the text given by @var{str2}.  This directive may appear
+more than once for the same name, and its order, along with @samp{F}, is
+important.
address@hidden table
 
 When loading format 1, the syntax categories @address@hidden and 
@address@hidden are
 disabled (reverting braces to be treated like plain characters).  This
@@ -8305,75 +8373,105 @@ because a newer version of M4 reloaded the file.
 
 @cindex frozen file format 2
 @cindex file format, frozen file version 2
-Frozen files are sharable across architectures.  It is safe to write
-a frozen file on one machine and read it on another, given that the
-second machine uses the same, or a newer version of GNU @code{m4}.
-These are simple (editable) text files, made up of directives,
-each starting with a capital letter and ending with a newline
-(@key{NL}).  Wherever a directive is expected, the character
address@hidden introduces a comment line, empty lines are also ignored.
-In the following descriptions, @var{length}s always refer to
-corresponding @var{string}s.  Numbers are always expressed in decimal.
-The directives are:
+The syntax of version 1 has some drawbacks; if any macro or diversion
+contained non-printable characters or long lines, the resulting frozen
+file would not qualify as a text file, making it harder to edit with
+some vendor tools.  The concatenation of multiple strings on a single
+line, such as for the @samp{T} directive, makes distinguishing the two
+strings a bit more difficult.  Finally, the format lacks support for
+several items of @code{m4} state, such that a reloaded file did not
+always behave the same as the original file.
+
+These shortcomings have been addressed in version 2 of the frozen file
+syntax.  New directives have been added, and existing directives have
+additional, and sometimes optional, parameters.
address@hidden FIXME - change implementation to match this:
address@hidden  All @var{str} instances
address@hidden in the grammar are now followed by @key{NL}, which makes the 
split
address@hidden between consecutive strings easier to recognize.
+Strings may now
+contain escape sequences modeled after C, such as @samp{\n} for newline
+or @samp{\0} for @sc{nul}, so that the frozen file can be pure
address@hidden (although when hand-editing a frozen file, it is still
+acceptable to use the original byte rather than an escape sequence for
+all bytes except @samp{\}).  Also in the context of a @var{str}, the
+escape sequence @address@hidden is discarded, allowing a user to split
+lines that are too long for some platform tools.
 
 @table @code
 @item V @var{number} @key{NL}
-Confirms the format of the file.  For the version documented here,
address@hidden should be 2.  It is backwards compatible with the previous
-version though, so version 1 frozen files can be loaded too if necessary.
-
address@hidden C @var{length1} , @var{length2} @key{NL} @var{string1} 
@var{string2} @key{NL}
-Uses @var{string1} and @var{string2} as the beginning comment and
-end comment strings.
-
address@hidden Q @var{length1} , @var{length2} @key{NL} @var{string1} 
@var{string2} @key{NL}
-Uses @var{string1} and @var{string2} as the beginning quote and end quote
-strings.
-
address@hidden R @var{length} @key{NL} @var{string} @key{NL}
-Sets the default regexp syntax, where @var{string} encodes one of the
+Confirms the format of the file.  @code{m4} @value{VERSION} only creates
+frozen files where @var{number} is 2.  This directive must be the first
+non-comment in the file, and may not appear more than once.
+
address@hidden    C @var{len1} , @var{len2} @key{NL} @var{str1} @key{NL} 
@var{str2} @key{NL}
address@hidden C @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
+Uses @var{str1} and @var{str2} as the begin-comment and
+end-comment strings.  If omitted, then @samp{#} and @key{NL} are the
+comment delimiters.
+
address@hidden d @var{len} @key{NL} @var{str} @key{NL}
+Sets the debug flags, using @var{str} as the argument to
address@hidden  If omitted, then the debug flags start in their
+default state.
+
address@hidden D @var{number} , @var{len} @key{NL} @var{str} @key{NL}
+Selects diversion @var{number}, making it current, then copy @var{str}
+in the current diversion.  @var{number} may be a negative number for a
+diversion that discards text.  To merely specify an active selection,
+use this command with an empty @var{string}.  With 0 as the diversion
address@hidden, @var{str} will be issued on standard output at reload
+time.  @acronym{GNU} @code{m4} will not produce the @samp{D} directive
+with non-zero length for diversion 0, but this can be done with manual
+edits.  This directive may appear more than once for the same diversion,
+in which case the diversion is the concatenation of the various uses.
+If omitted, then diversion 0 is current.
+
address@hidden FIXME - the first usage, with only one string, is not supported
address@hidden in the current code
address@hidden F @var{len1} @key{NL} @var{str1} @key{NL}
address@hidden F @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
address@hidden F @var{len1} , @var{len2} , @var{len3} @key{NL} @var{str1} 
@var{str2} @var{str3} @key{NL}
+Defines, through @code{pushdef}, a definition for @var{str1} expanding
+to the function whose builtin name is given by @var{str2} (defaulting to
address@hidden if not present).  With two arguments, the builtin name is
+searched for among the intrinsic builtin functions only; with three
+arguments, the builtin name is searched for amongst the builtin
+functions defined by the module named by @var{str3}.
+
address@hidden M @var{len} @key{NL} @var{str} @key{NL}
+Names a module which will be searched for according to the module search
+path and loaded.  Modules loaded from a frozen file don't add their
+builtin entries to the symbol table.  Modules must be loaded prior to
+specifying module-specific builtins via the three-argument @code{F} or
address@hidden
+
address@hidden Q @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
+Uses @var{str1} and @var{str2} as the begin-quote and end-quote strings.
+If omitted, then @samp{`} and @samp{'} are the quote delimiters.
+
address@hidden R @var{len} @key{NL} @var{str} @key{NL}
+Sets the default regexp syntax, where @var{str} encodes one of the
 regular expression syntaxes supported by @acronym{GNU} M4.
 @xref{Changeresyntax}, for more details.
 
address@hidden M @var{length} @key{NL} @var{string} @key{NL}
-Names a module which will be searched for according to the module search path
-and loaded.  Modules loaded from a frozen file don't add their builtin entries
-to the symbol table.
-
address@hidden F @var{length} @key{NL} @var{string} @key{NL}
-Defines, through @code{pushdef}, a definition for @var{string}
-expanding to the function whose builtin name is also @var{string}.  The builtin
-name is searched for among the intrinsic builtin functions only.
-
address@hidden F @var{length1} , @var{length2} @key{NL} @var{string1} 
@var{string2} @key{NL}
-Defines, through @code{pushdef}, a definition for @var{string1}
-expanding to the function whose builtin name is @var{string2}.  With two
-arguments, the builtin name is searched for among the intrinsic builtin
-functions only.
-
address@hidden F @var{length1} , @var{length2} , @var{length3} @key{NL} 
@var{string1} @var{string2} @var{string3} @key{NL}
-Defines, through @code{pushdef}, a definition for @var{string1}
-expanding to the function whose builtin name is @var{string2}.  With three
-arguments, the builtin name is searched for amongst the builtin functions
-defined by the module named by @var{string3}.
-
address@hidden S @var{syntax-code} @var{length} @key{NL} @var{string} @key{NL}
address@hidden S @var{syntax-code} @var{len} @key{NL} @var{str} @key{NL}
 Defines, through @code{changesyntax}, a syntax category for each of the
-characters in @var{string}.  The @var{syntax-code} must be one of the
+characters in @var{str}.  The @var{syntax-code} must be one of the
 characters described in @ref{Changesyntax}.
 
address@hidden T @var{length1} , @var{length2} @key{NL} @var{string1} 
@var{string2} @key{NL}
-Defines, though @code{pushdef}, a definition for @var{string1}
-expanding to the text given by @var{string2}.
-
address@hidden D @var{number}, @var{length} @key{NL} @var{string} @key{NL}
-Selects diversion @var{number}, making it current, then copy
address@hidden in the current diversion.  @var{number} may be a negative
-number for a non-existing diversion.  To merely specify an active
-selection, use this command with an empty @var{string}.  With 0 as the
-diversion @var{number}, @var{string} will be issued on standard output
-at reload time, however this may not be produced from within @code{m4}.
-
address@hidden t @var{len} @key{NL} @var{str} @key{NL}
+Enables tracing for any macro named @var{str}, similar to using the
address@hidden builtin.  This option may occur more than once for
+multiple macros; if omitted, no macro starts out as traced.
+
address@hidden FIXME - what about a module's text macros, like __gnu__?
address@hidden T @var{len1} , @var{len2} @key{NL} @var{str1} @var{str2} @key{NL}
+Defines, though @code{pushdef}, a definition for @var{str1} expanding to
+the text given by @var{str2}.  With two arguments, the builtin name is
+searched for among the intrinsic builtin functions only; with three
+arguments, the builtin name is searched for amongst the builtin
+functions defined by the module named by @var{str3}.
 @end table
 
 @node Compatibility
diff --git a/src/freeze.c b/src/freeze.c
index ac67d56..db5a1cf 100644
--- a/src/freeze.c
+++ b/src/freeze.c
@@ -103,6 +103,43 @@ produce_syntax_dump (FILE *file, m4_syntax_table *syntax, 
char ch)
     }
 }
 
+/* Store the debug mode in textual format.  */
+static void
+produce_debugmode_state (FILE *file, int flags)
+{
+  /* This code tracks the number of bits in M4_DEBUG_TRACE_VERBOSE.  */
+  char str[13];
+  int offset = 0;
+  assert ((1 << (sizeof str - 1)) - 1 == M4_DEBUG_TRACE_VERBOSE);
+  if (flags & M4_DEBUG_TRACE_ARGS)
+    str[offset++] = 'a';
+  if (flags & M4_DEBUG_TRACE_EXPANSION)
+    str[offset++] = 'e';
+  if (flags & M4_DEBUG_TRACE_QUOTE)
+    str[offset++] = 'q';
+  if (flags & M4_DEBUG_TRACE_ALL)
+    str[offset++] = 't';
+  if (flags & M4_DEBUG_TRACE_LINE)
+    str[offset++] = 'l';
+  if (flags & M4_DEBUG_TRACE_FILE)
+    str[offset++] = 'f';
+  if (flags & M4_DEBUG_TRACE_PATH)
+    str[offset++] = 'p';
+  if (flags & M4_DEBUG_TRACE_CALL)
+    str[offset++] = 'c';
+  if (flags & M4_DEBUG_TRACE_INPUT)
+    str[offset++] = 'i';
+  if (flags & M4_DEBUG_TRACE_CALLID)
+    str[offset++] = 'x';
+  if (flags & M4_DEBUG_TRACE_MODULE)
+    str[offset++] = 'm';
+  if (flags & M4_DEBUG_TRACE_STACK)
+    str[offset++] = 's';
+  str[offset] = '\0';
+  if (offset)
+    xfprintf (file, "d%d\n%s\n", offset, str);
+}
+
 /* The modules must be dumped in the order in which they will be
    reloaded from the frozen file.  libltdl stores handles in a push
    down stack, so we need to dump them in the reverse order to that.  */
@@ -127,7 +164,7 @@ produce_module_dump (FILE *file, m4_module *module)
 static void
 produce_symbol_dump (m4 *context, FILE *file, m4_symbol_table *symtab)
 {
-  if (m4_symtab_apply (symtab, false, dump_symbol_CB, file))
+  if (m4_symtab_apply (symtab, true, dump_symbol_CB, file))
     assert (false);
 }
 
@@ -210,6 +247,8 @@ dump_symbol_CB (m4_symbol_table *symtab, const char 
*symbol_name,
       value = VALUE_NEXT (value);
     }
   reverse_symbol_value_stack (last);
+  if (m4_get_symbol_traced (symbol))
+    xfprintf (file, "t%zu\n%s\n", symbol_len, symbol_name);
   return NULL;
 }
 
@@ -254,15 +293,16 @@ produce_frozen_state (m4 *context, const char *name)
     }
 
   /* Dump regular expression syntax.  */
-
   produce_resyntax_dump (context, file);
 
   /* Dump syntax table.  */
-
   str = "address@hidden(),RE";
   while (*str)
     produce_syntax_dump (file, M4SYNTAX, *str++);
 
+  /* Dump debugmode state.  */
+  produce_debugmode_state (file, m4_get_debug_level_opt (context));
+
   /* Dump all loaded modules.  */
   produce_module_dump (file, m4__module_next (NULL));
 
@@ -548,6 +588,26 @@ reload_frozen_state (m4 *context, const char *name)
                    _("ill-formed frozen file, unknown directive %c"),
                    character);
 
+       case 'd':
+         /* Set debugmode flags.  */
+         if (version < 2)
+           {
+             /* 'd' operator is not supported in format version 1. */
+             m4_error (context, EXIT_FAILURE, 0, NULL, _("\
+ill-formed frozen file, version 2 directive `%c' encountered"), 'd');
+           }
+
+         GET_CHARACTER;
+         GET_NUMBER (number[0], false);
+         VALIDATE ('\n');
+         GET_STRING (file, string[0], allocated[0], number[0]);
+         VALIDATE ('\n');
+
+         m4_set_debug_level_opt (context, m4_debug_decode (context, 0,
+                                                           string[0]));
+
+         break;
+
        case 'F':
          GET_CHARACTER;
 
@@ -686,6 +746,25 @@ ill-formed frozen file, version 2 directive `%c' 
encountered"), 'S');
            }
          break;
 
+       case 't':
+         /* Trace a macro name.  */
+         if (version < 2)
+           {
+             /* 't' operator is not supported in format version 1. */
+             m4_error (context, EXIT_FAILURE, 0, NULL, _("\
+ill-formed frozen file, version 2 directive `%c' encountered"), 't');
+           }
+
+         GET_CHARACTER;
+         GET_NUMBER (number[0], false);
+         VALIDATE ('\n');
+         GET_STRING (file, string[0], allocated[0], number[0]);
+         VALIDATE ('\n');
+
+         m4_set_symbol_name_traced (M4SYMTAB, string[0], true);
+
+         break;
+
        case 'C':
        case 'D':
        case 'Q':
diff --git a/tests/freeze.at b/tests/freeze.at
index e8ada67..209c611 100644
--- a/tests/freeze.at
+++ b/tests/freeze.at
@@ -301,6 +301,22 @@ define{`a.b', `hello $1'}dnl
 [[a.b{world}
 ]])
 
+## ------- ##
+## pushdef ##
+## ------- ##
+
+# Check for pushdef stacks; broken 2001-09-01, fixed 2008-05-15.
+AT_TEST_FREEZE([reloading pushdef stack],
+[[pushdef(`foo', `1')
+pushdef(`foo', defn(`len'))
+pushdef(`foo', `3')
+]],
+[[foo(`abc')popdef(`foo')
+foo(`ab')popdef(`foo')
+foo(`a')popdef(`foo')
+foo
+]])
+
 ## ------------- ##
 ## regexp syntax ##
 ## ------------- ##
@@ -313,20 +329,24 @@ AT_TEST_FREEZE([reloading regexp syntax],
 regexp(`GNUs not Unix', `\w\(\w*\)$', `GNU_M4')
 ]])
 
-## ------- ##
-## pushdef ##
-## ------- ##
+## ----- ##
+## trace ##
+## ----- ##
 
-# Check for pushdef stacks; broken 2001-09-01, fixed 2008-05-15.
-AT_TEST_FREEZE([reloading pushdef stack],
-[[pushdef(`foo', `1')
-pushdef(`foo', defn(`len'))
-pushdef(`foo', `3')
+# Check for macro tracing, both single and global.
+AT_TEST_FREEZE([reloading traced macros],
+[[define(`text', `hello world')dnl
+define(`foo', `bar')dnl
+traceon(`blah', `divnum', `text')dnl
+traceon
 ]],
-[[foo(`abc')popdef(`foo')
-foo(`ab')popdef(`foo')
-foo(`a')popdef(`foo')
+[[foo
+traceoff
 foo
+text
+divnum
+ifdef(`blah', `', `define(`blah', `finally')')dnl
+blah
 ]])
 
 ## ---------------- ##
-- 
1.5.5.1