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Fix bug#1379: don't use alloca() where it could overrun the stack size.

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Implemented enhancement #1391: allow "export" in target-specific
variable definitions.

Change the Info name of the "Automatic" node to "Automatic Variables".
Add text clarifying the scope of automatic variables to that section.
This commit is contained in:
Paul Smith 2002-10-13 18:50:10 +00:00
parent 47cd8d4624
commit 8bbdbb02b3
6 changed files with 111 additions and 39 deletions
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19
ChangeLog
View File

@ -1,3 +1,22 @@
2002-10-13 Paul D. Smith <psmith@gnu.org>
* commands.c (set_file_variables): Bug #1379: Don't use alloca()
for automatic variable values like $^, etc. In the case of very
large lists of prerequisites this causes problems. Instead reuse
a static buffer (resizeable) for each variable.
* read.c (eval): Fix Bug #1391: allow "export" keyword in
target-specific variable definitions. Check for it and set an
"exported" flag.
(record_target_var): Set the export field to v_export if the
"exported" flag is set.
* doc/make.texi (Target-specific): Document the ability to use
"export".
* doc/make.texi: Change the name of the section on automatic
variables from "Automatic" to "Automatic Variables". Added text
clarifying the scope of automatic variables.
2002-10-04 Paul D. Smith <psmith@gnu.org>
* read.c (eval): Allow SysV $$@ variables to use {} braces as well

21
commands.c
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@ -127,11 +127,12 @@ set_file_variables (file)
/* Compute the values for $^, $+, $?, and $|. */
{
static char *plus_value=0, *bar_value=0, *qmark_value=0;
static int qmark_max=0, plus_max=0, bar_max=0;
unsigned int qmark_len, plus_len, bar_len;
char *caret_value, *plus_value;
char *cp;
char *qmark_value;
char *bar_value;
char *caret_value;
char *qp;
char *bp;
struct dep *d;
@ -147,7 +148,9 @@ set_file_variables (file)
if (plus_len == 0)
plus_len++;
cp = plus_value = (char *) alloca (plus_len);
if (plus_len > plus_max)
plus_value = (char *) xmalloc (plus_max = plus_len);
cp = plus_value;
qmark_len = plus_len + 1; /* Will be this or less. */
for (d = file->deps; d != 0; d = d->next)
@ -193,8 +196,14 @@ set_file_variables (file)
/* Compute the values for $^, $?, and $|. */
cp = caret_value = plus_value; /* Reuse the buffer; it's big enough. */
qp = qmark_value = (char *) alloca (qmark_len);
bp = bar_value = (char *) alloca (bar_len);
if (qmark_len > qmark_max)
qmark_value = (char *) xmalloc (qmark_max = qmark_len);
qp = qmark_value;
if (bar_len > bar_max)
bar_value = (char *) xmalloc (bar_max = bar_len);
bp = bar_value;
for (d = file->deps; d != 0; d = d->next)
{

66
doc/make.texi
View File

@ -308,7 +308,7 @@ Defining and Redefining Pattern Rules
* Pattern Intro:: An introduction to pattern rules.
* Pattern Examples:: Examples of pattern rules.
* Automatic:: How to use automatic variables in the
* Automatic Variables:: How to use automatic variables in the
commands of implicit rules.
* Pattern Match:: How patterns match.
* Match-Anything Rules:: Precautions you should take prior to
@ -1776,7 +1776,7 @@ print: *.c
This rule uses @file{print} as an empty target file; see @ref{Empty
Targets, ,Empty Target Files to Record Events}. (The automatic variable
@samp{$?} is used to print only those files that have changed; see
@ref{Automatic, ,Automatic Variables}.)@refill
@ref{Automatic Variables}.)@refill
Wildcard expansion does not happen when you define a variable. Thus, if
you write this:
@ -2171,7 +2171,7 @@ Therefore, you must write the commands with care so that they will look for
the prerequisite in the directory where @code{make} finds it.
This is done with the @dfn{automatic variables} such as @samp{$^}
(@pxref{Automatic, ,Automatic Variables}).
(@pxref{Automatic Variables}).
For instance, the value of @samp{$^} is a
list of all the prerequisites of the rule, including the names of
the directories in which they were found, and the value of
@ -2514,7 +2514,7 @@ print: foo.c bar.c
With this rule, @samp{make print} will execute the @code{lpr} command if
either source file has changed since the last @samp{make print}. The
automatic variable @samp{$?} is used to print only those files that have
changed (@pxref{Automatic, ,Automatic Variables}).
changed (@pxref{Automatic Variables}).
@node Special Targets, Multiple Targets, Empty Targets, Rules
@section Special Built-in Target Names
@ -2724,7 +2724,7 @@ mentioned.
Similar commands work for all the targets. The commands do not need
to be absolutely identical, since the automatic variable @samp{$@@}
can be used to substitute the particular target to be remade into the
commands (@pxref{Automatic, ,Automatic Variables}). For example:
commands (@pxref{Automatic Variables}). For example:
@example
@group
@ -2912,7 +2912,7 @@ $(objects): %.o: %.c
@noindent
Here @samp{$<} is the automatic variable that holds the name of the
prerequisite and @samp{$@@} is the automatic variable that holds the name
of the target; see @ref{Automatic, , Automatic Variables}.
of the target; see @ref{Automatic Variables}.
Each target specified must match the target pattern; a warning is issued
for each target that does not. If you have a list of files, only some of
@ -4234,7 +4234,7 @@ command options (@pxref{Overriding, ,Overriding Variables}).
A few variables have names that are a single punctuation character or
just a few characters. These are the @dfn{automatic variables}, and
they have particular specialized uses. @xref{Automatic, ,Automatic Variables}.
they have particular specialized uses. @xref{Automatic Variables}.
@menu
* Reference:: How to use the value of a variable.
@ -4303,7 +4303,7 @@ A dollar sign followed by a character other than a dollar sign,
open-parenthesis or open-brace treats that single character as the
variable name. Thus, you could reference the variable @code{x} with
@samp{$x}. However, this practice is strongly discouraged, except in
the case of the automatic variables (@pxref{Automatic, ,Automatic Variables}).
the case of the automatic variables (@pxref{Automatic Variables}).
@node Flavors, Advanced, Reference, Using Variables
@section The Two Flavors of Variables
@ -4787,7 +4787,7 @@ Variables in the environment become @code{make} variables.
@item
Several @dfn{automatic} variables are given new values for each rule.
Each of these has a single conventional use.
@xref{Automatic, ,Automatic Variables}.
@xref{Automatic Variables}.
@item
Several variables have constant initial values.
@ -4835,7 +4835,7 @@ that are not empty, but you can set them in the usual ways
(@pxref{Implicit Variables, ,Variables Used by Implicit Rules}).
Several special variables are set
automatically to a new value for each rule; these are called the
@dfn{automatic} variables (@pxref{Automatic, ,Automatic Variables}).
@dfn{automatic} variables (@pxref{Automatic Variables}).
If you'd like a variable to be set to a value only if it's not already
set, then you can use the shorthand operator @samp{?=} instead of
@ -5173,7 +5173,7 @@ MS-DOS}.)@refill
Variable values in @code{make} are usually global; that is, they are the
same regardless of where they are evaluated (unless they're reset, of
course). One exception to that is automatic variables
(@pxref{Automatic, ,Automatic Variables}).
(@pxref{Automatic Variables}).
The other exception is @dfn{target-specific variable values}. This
feature allows you to define different values for the same variable,
@ -5194,6 +5194,13 @@ or like this:
@var{target} @dots{} : override @var{variable-assignment}
@end example
@noindent
or like this:
@example
@var{target} @dots{} : export @var{variable-assignment}
@end example
Multiple @var{target} values create a target-specific variable value for
each member of the target list individually.
@ -5515,7 +5522,7 @@ beginning or the end of the conditional.@refill
@code{make} evaluates conditionals when it reads a makefile.
Consequently, you cannot use automatic variables in the tests of
conditionals because they are not defined until commands are run
(@pxref{Automatic, , Automatic Variables}).
(@pxref{Automatic Variables}).
To prevent intolerable confusion, it is not permitted to start a
conditional in one makefile and end it in another. However, you may
@ -6517,7 +6524,7 @@ makefile (@pxref{Override Directive, ,The @code{override} Directive}).
if @var{variable} is an automatic variable defined for the
execution of the commands for each rule
(@pxref{Automatic, , Automatic Variables}).
(@pxref{Automatic Variables}).
@end table
This information is primarily useful (other than for your curiosity) to
@ -8185,7 +8192,7 @@ Variables}, and @ref{Functions, ,Functions for Transforming Text}.
@menu
* Pattern Intro:: An introduction to pattern rules.
* Pattern Examples:: Examples of pattern rules.
* Automatic:: How to use automatic variables in the
* Automatic Variables:: How to use automatic variables in the
commands of implicit rules.
* Pattern Match:: How patterns match.
* Match-Anything Rules:: Precautions you should take prior to
@ -8263,7 +8270,7 @@ rule with prerequisites that must be made by chaining other implicit rules.
@cindex pattern rules, order of
@cindex order of pattern rules
@node Pattern Examples, Automatic, Pattern Intro, Pattern Rules
@node Pattern Examples, Automatic Variables, Pattern Intro, Pattern Rules
@subsection Pattern Rule Examples
Here are some examples of pattern rules actually predefined in
@ -8279,7 +8286,7 @@ files:@refill
defines a rule that can make any file @file{@var{x}.o} from
@file{@var{x}.c}. The command uses the automatic variables @samp{$@@} and
@samp{$<} to substitute the names of the target file and the source file
in each case where the rule applies (@pxref{Automatic, ,Automatic Variables}).@refill
in each case where the rule applies (@pxref{Automatic Variables}).@refill
Here is a second built-in rule:
@ -8320,7 +8327,7 @@ and the file @file{scan.o} from @file{scan.c}, while @file{foo} is
linked from @file{parse.tab.o}, @file{scan.o}, and its other
prerequisites, and it will execute happily ever after.)@refill
@node Automatic, Pattern Match, Pattern Examples, Pattern Rules
@node Automatic Variables, Pattern Match, Pattern Examples, Pattern Rules
@subsection Automatic Variables
@cindex automatic variables
@cindex variables, automatic
@ -8337,6 +8344,17 @@ is executed, based on the target and prerequisites of the rule. In this
example, you would use @samp{$@@} for the object file name and @samp{$<}
for the source file name.
@cindex automatic variables in prerequisites
@cindex prerequisites, and automatic variables
It's very important that you recognize the limited scope in which
automatic variable values are available: they only have values within
the command script. In particular, you cannot use them anywhere
within the target or prerequisite lists of a rule; they have no value
there and will expand to the empty string. A common mistake is
attempting to use @code{$@@} within the prerequisites list in a rule;
this will not work. However, see below for information on the
SysV-style @code{$$@@} variables.
Here is a table of automatic variables:
@table @code
@ -8551,7 +8569,7 @@ compatibility with SysV makefiles. In a native GNU @code{make} file
there are other ways to accomplish the same results. This feature is
disabled if the special pseudo target @code{.POSIX} is defined.
@node Pattern Match, Match-Anything Rules, Automatic, Pattern Rules
@node Pattern Match, Match-Anything Rules, Automatic Variables, Pattern Rules
@subsection How Patterns Match
@cindex stem
@ -8930,7 +8948,7 @@ update status as the file @var{t}.
When the commands of a pattern rule are executed for @var{t}, the automatic
variables are set corresponding to the target and prerequisites.
@xref{Automatic, ,Automatic Variables}.
@xref{Automatic Variables}.
@node Archives, Features, Implicit Rules, Top
@chapter Using @code{make} to Update Archive Files
@ -9033,7 +9051,7 @@ Here @code{make} has envisioned the file @file{bar.o} as an intermediate
file. @xref{Chained Rules, ,Chains of Implicit Rules}.
Implicit rules such as this one are written using the automatic variable
@samp{$%}. @xref{Automatic, ,Automatic Variables}.
@samp{$%}. @xref{Automatic Variables}.
An archive member name in an archive cannot contain a directory name, but
it may be useful in a makefile to pretend that it does. If you write an
@ -9196,13 +9214,13 @@ invocations of @code{make}.
@item
The automatic variable @code{$%} is set to the member name
in an archive reference. @xref{Automatic, ,Automatic Variables}.
in an archive reference. @xref{Automatic Variables}.
@item
The automatic variables @code{$@@}, @code{$*}, @code{$<}, @code{$%},
and @code{$?} have corresponding forms like @code{$(@@F)} and
@code{$(@@D)}. We have generalized this to @code{$^} as an obvious
extension. @xref{Automatic, ,Automatic Variables}.@refill
extension. @xref{Automatic Variables}.@refill
@item
Substitution variable references.
@ -9254,7 +9272,7 @@ same time. @xref{Chained Rules, ,Chains of Implicit Rules}.
@item
The automatic variable @code{$^} containing a list of all prerequisites
of the current target. We did not invent this, but we have no idea who
did. @xref{Automatic, ,Automatic Variables}. The automatic variable
did. @xref{Automatic Variables}. The automatic variable
@code{$+} is a simple extension of @code{$^}.
@item
@ -9711,7 +9729,7 @@ Evaluate the variable @var{var} replacing any references to @code{$(1)},
@end table
Here is a summary of the automatic variables.
@xref{Automatic, ,Automatic Variables},
@xref{Automatic Variables},
for full information.
@table @code

31
read.c
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@ -139,6 +139,7 @@ static void record_files PARAMS ((struct nameseq *filenames, char *pattern, char
static void record_target_var PARAMS ((struct nameseq *filenames, char *defn,
int two_colon,
enum variable_origin origin,
int enabled,
const struct floc *flocp));
static enum make_word_type get_next_mword PARAMS ((char *buffer, char *delim,
char **startp, unsigned int *length));
@ -860,6 +861,7 @@ eval (ebuf, set_default)
{
enum make_word_type wtype;
enum variable_origin v_origin;
int exported;
char *cmdleft, *semip, *lb_next;
unsigned int len, plen = 0;
char *colonp;
@ -1024,17 +1026,24 @@ eval (ebuf, set_default)
p2 = variable_buffer + l;
}
/* See if it's an "override" keyword; if so see if what comes after
it looks like a variable definition. */
/* See if it's an "override" or "export" keyword; if so see if what
comes after it looks like a variable definition. */
wtype = get_next_mword (p2, NULL, &p, &len);
v_origin = o_file;
if (wtype == w_static && word1eq ("override"))
{
v_origin = o_override;
wtype = get_next_mword (p+len, NULL, &p, &len);
}
exported = 0;
if (wtype == w_static)
if (word1eq ("override"))
{
v_origin = o_override;
wtype = get_next_mword (p+len, NULL, &p, &len);
}
else if (word1eq ("export"))
{
exported = 1;
wtype = get_next_mword (p+len, NULL, &p, &len);
}
if (wtype != w_eol)
wtype = get_next_mword (p+len, NULL, NULL, NULL);
@ -1049,7 +1058,8 @@ eval (ebuf, set_default)
variable_buffer_output (p2 + strlen (p2),
semip, strlen (semip)+1);
}
record_target_var (filenames, p, two_colon, v_origin, fstart);
record_target_var (filenames, p, two_colon, v_origin, exported,
fstart);
filenames = 0;
continue;
}
@ -1628,11 +1638,12 @@ uniquize_deps (chain)
variable value list. */
static void
record_target_var (filenames, defn, two_colon, origin, flocp)
record_target_var (filenames, defn, two_colon, origin, exported, flocp)
struct nameseq *filenames;
char *defn;
int two_colon;
enum variable_origin origin;
int exported;
const struct floc *flocp;
{
struct nameseq *nextf;
@ -1691,6 +1702,8 @@ record_target_var (filenames, defn, two_colon, origin, flocp)
if (!v)
error (flocp, _("Malformed per-target variable definition"));
v->per_target = 1;
if (exported)
v->export = v_export;
/* If it's not an override, check to see if there was a command-line
setting. If so, reset the value. */

5
tests/ChangeLog
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@ -1,3 +1,8 @@
2002-10-13 Paul D. Smith <psmith@gnu.org>
* scripts/features/targetvars: Add a test for exporting
target-specific vars (Bug #1391).
2002-10-05 Paul D. Smith <psmith@gnu.org>
* scripts/variables/automatic: Add tests for $$(@), $${@}, $${@D},

8
tests/scripts/features/targetvars
View File

@ -37,6 +37,8 @@ eight: BAR = eight
# Test the export keyword with per-target variables
nine: ; @echo $(FOO) $(BAR) $$FOO $$BAR
nine: FOO = wallace
nine-a: export BAZ = baz
nine-a: ; @echo $$BAZ
# Test = escaping
EQ = =
ten: one\=two
@ -86,6 +88,12 @@ $answer = "eight: seven eight\nseven: seven seven\n";
$answer = "wallace bar wallace bar\n";
&compare_output($answer,&get_logfile(1));
# TEST #5-a
&run_make_with_options($makefile, "nine-a", &get_logfile);
$answer = "baz\n";
&compare_output($answer,&get_logfile(1));
# TEST #6
&run_make_with_options($makefile, "ten", &get_logfile);