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

Browse Source 
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> 2002-10-04 Paul D. Smith <psmith@gnu.org>
* read.c (eval): Allow SysV $$@ variables to use {} braces as well * read.c (eval): Allow SysV $$@ variables to use {} braces as well

21
commands.c
View File

@ -127,11 +127,12 @@ set_file_variables (file)
/* Compute the values for $^, $+, $?, and $|. */ /* 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; unsigned int qmark_len, plus_len, bar_len;
char *caret_value, *plus_value;
char *cp; char *cp;
char *qmark_value; char *caret_value;
char *bar_value;
char *qp; char *qp;
char *bp; char *bp;
struct dep *d; struct dep *d;
@ -147,7 +148,9 @@ set_file_variables (file)
if (plus_len == 0) if (plus_len == 0)
plus_len++; 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. */ qmark_len = plus_len + 1; /* Will be this or less. */
for (d = file->deps; d != 0; d = d->next) for (d = file->deps; d != 0; d = d->next)
@ -193,8 +196,14 @@ set_file_variables (file)
/* Compute the values for $^, $?, and $|. */ /* Compute the values for $^, $?, and $|. */
cp = caret_value = plus_value; /* Reuse the buffer; it's big enough. */ 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) 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 Intro:: An introduction to pattern rules.
* Pattern Examples:: Examples of 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. commands of implicit rules.
* Pattern Match:: How patterns match. * Pattern Match:: How patterns match.
* Match-Anything Rules:: Precautions you should take prior to * 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 This rule uses @file{print} as an empty target file; see @ref{Empty
Targets, ,Empty Target Files to Record Events}. (The automatic variable Targets, ,Empty Target Files to Record Events}. (The automatic variable
@samp{$?} is used to print only those files that have changed; see @samp{$?} 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 Wildcard expansion does not happen when you define a variable. Thus, if
you write this: 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. the prerequisite in the directory where @code{make} finds it.
This is done with the @dfn{automatic variables} such as @samp{$^} This is done with the @dfn{automatic variables} such as @samp{$^}
(@pxref{Automatic, ,Automatic Variables}). (@pxref{Automatic Variables}).
For instance, the value of @samp{$^} is a For instance, the value of @samp{$^} is a
list of all the prerequisites of the rule, including the names of list of all the prerequisites of the rule, including the names of
the directories in which they were found, and the value 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 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 either source file has changed since the last @samp{make print}. The
automatic variable @samp{$?} is used to print only those files that have automatic variable @samp{$?} 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 @node Special Targets, Multiple Targets, Empty Targets, Rules
@section Special Built-in Target Names @section Special Built-in Target Names
@ -2724,7 +2724,7 @@ mentioned.
Similar commands work for all the targets. The commands do not need Similar commands work for all the targets. The commands do not need
to be absolutely identical, since the automatic variable @samp{$@@} to be absolutely identical, since the automatic variable @samp{$@@}
can be used to substitute the particular target to be remade into the 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 @example
@group @group
@ -2912,7 +2912,7 @@ $(objects): %.o: %.c
@noindent @noindent
Here @samp{$<} is the automatic variable that holds the name of the Here @samp{$<} is the automatic variable that holds the name of the
prerequisite and @samp{$@@} is the automatic variable that holds the name prerequisite and @samp{$@@} is the automatic variable that holds the name
of the target; see @ref{Automatic, , Automatic Variables}. of the target; see @ref{Automatic Variables}.
Each target specified must match the target pattern; a warning is issued Each target specified must match the target pattern; a warning is issued
for each target that does not. If you have a list of files, only some of for each target that does not. If you have a list of files, only some of
@ -4234,7 +4234,7 @@ command options (@pxref{Overriding, ,Overriding Variables}).
A few variables have names that are a single punctuation character or A few variables have names that are a single punctuation character or
just a few characters. These are the @dfn{automatic variables}, and just a few characters. These are the @dfn{automatic variables}, and
they have particular specialized uses. @xref{Automatic, ,Automatic Variables}. they have particular specialized uses. @xref{Automatic Variables}.
@menu @menu
* Reference:: How to use the value of a variable. * Reference:: How to use the value of a variable.
@ -4303,7 +4303,7 @@ A dollar sign followed by a character other than a dollar sign,
open-parenthesis or open-brace treats that single character as the open-parenthesis or open-brace treats that single character as the
variable name. Thus, you could reference the variable @code{x} with variable name. Thus, you could reference the variable @code{x} with
@samp{$x}. However, this practice is strongly discouraged, except in @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 @node Flavors, Advanced, Reference, Using Variables
@section The Two Flavors of Variables @section The Two Flavors of Variables
@ -4787,7 +4787,7 @@ Variables in the environment become @code{make} variables.
@item @item
Several @dfn{automatic} variables are given new values for each rule. Several @dfn{automatic} variables are given new values for each rule.
Each of these has a single conventional use. Each of these has a single conventional use.
@xref{Automatic, ,Automatic Variables}. @xref{Automatic Variables}.
@item @item
Several variables have constant initial values. 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}). (@pxref{Implicit Variables, ,Variables Used by Implicit Rules}).
Several special variables are set Several special variables are set
automatically to a new value for each rule; these are called the 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 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 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 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 same regardless of where they are evaluated (unless they're reset, of
course). One exception to that is automatic variables 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 The other exception is @dfn{target-specific variable values}. This
feature allows you to define different values for the same variable, 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} @var{target} @dots{} : override @var{variable-assignment}
@end example @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 Multiple @var{target} values create a target-specific variable value for
each member of the target list individually. 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. @code{make} evaluates conditionals when it reads a makefile.
Consequently, you cannot use automatic variables in the tests of Consequently, you cannot use automatic variables in the tests of
conditionals because they are not defined until commands are run 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 To prevent intolerable confusion, it is not permitted to start a
conditional in one makefile and end it in another. However, you may 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 if @var{variable} is an automatic variable defined for the
execution of the commands for each rule execution of the commands for each rule
(@pxref{Automatic, , Automatic Variables}). (@pxref{Automatic Variables}).
@end table @end table
This information is primarily useful (other than for your curiosity) to This information is primarily useful (other than for your curiosity) to
@ -8185,7 +8192,7 @@ Variables}, and @ref{Functions, ,Functions for Transforming Text}.
@menu @menu
* Pattern Intro:: An introduction to pattern rules. * Pattern Intro:: An introduction to pattern rules.
* Pattern Examples:: Examples of 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. commands of implicit rules.
* Pattern Match:: How patterns match. * Pattern Match:: How patterns match.
* Match-Anything Rules:: Precautions you should take prior to * 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 pattern rules, order of
@cindex order of pattern rules @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 @subsection Pattern Rule Examples
Here are some examples of pattern rules actually predefined in 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 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 @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 @samp{$<} to substitute the names of the target file and the source file
in each case where the rule applies (@pxref{Automatic, ,Automatic Variables}).@refill in each case where the rule applies (@pxref{Automatic Variables}).@refill
Here is a second built-in rule: Here is a second built-in rule:
@ -8320,7 +8327,7 @@ and the file @file{scan.o} from @file{scan.c}, while @file{foo} is
linked from @file{parse.tab.o}, @file{scan.o}, and its other linked from @file{parse.tab.o}, @file{scan.o}, and its other
prerequisites, and it will execute happily ever after.)@refill prerequisites, and it will execute happily ever after.)@refill
@node Automatic, Pattern Match, Pattern Examples, Pattern Rules @node Automatic Variables, Pattern Match, Pattern Examples, Pattern Rules
@subsection Automatic Variables @subsection Automatic Variables
@cindex automatic variables @cindex automatic variables
@cindex variables, automatic @cindex variables, automatic
@ -8337,6 +8344,17 @@ is executed, based on the target and prerequisites of the rule. In this
example, you would use @samp{$@@} for the object file name and @samp{$<} example, you would use @samp{$@@} for the object file name and @samp{$<}
for the source file name. for the source file name.
@cindex automatic variables in prerequisites
@cindex prerequisites, and automatic variables
It's very important that you recognize the limited scope in which
automatic variable values are available: they only have values within
the command script. In particular, you cannot use them anywhere
within the target or prerequisite lists of a rule; they have no value
there and will expand to the empty string. A common mistake is
attempting to use @code{$@@} 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: Here is a table of automatic variables:
@table @code @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 there are other ways to accomplish the same results. This feature is
disabled if the special pseudo target @code{.POSIX} is defined. 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 @subsection How Patterns Match
@cindex stem @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 When the commands of a pattern rule are executed for @var{t}, the automatic
variables are set corresponding to the target and prerequisites. variables are set corresponding to the target and prerequisites.
@xref{Automatic, ,Automatic Variables}. @xref{Automatic Variables}.
@node Archives, Features, Implicit Rules, Top @node Archives, Features, Implicit Rules, Top
@chapter Using @code{make} to Update Archive Files @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}. file. @xref{Chained Rules, ,Chains of Implicit Rules}.
Implicit rules such as this one are written using the automatic variable 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 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 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 @item
The automatic variable @code{$%} is set to the member name The automatic variable @code{$%} is set to the member name
in an archive reference. @xref{Automatic, ,Automatic Variables}. in an archive reference. @xref{Automatic Variables}.
@item @item
The automatic variables @code{$@@}, @code{$*}, @code{$<}, @code{$%}, The automatic variables @code{$@@}, @code{$*}, @code{$<}, @code{$%},
and @code{$?} have corresponding forms like @code{$(@@F)} and and @code{$?} have corresponding forms like @code{$(@@F)} and
@code{$(@@D)}. We have generalized this to @code{$^} as an obvious @code{$(@@D)}. We have generalized this to @code{$^} as an obvious
extension. @xref{Automatic, ,Automatic Variables}.@refill extension. @xref{Automatic Variables}.@refill
@item @item
Substitution variable references. Substitution variable references.
@ -9254,7 +9272,7 @@ same time. @xref{Chained Rules, ,Chains of Implicit Rules}.
@item @item
The automatic variable @code{$^} containing a list of all prerequisites The automatic variable @code{$^} containing a list of all prerequisites
of the current target. We did not invent this, but we have no idea who 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{$+} is a simple extension of @code{$^}. @code{$+} is a simple extension of @code{$^}.
@item @item
@ -9711,7 +9729,7 @@ Evaluate the variable @var{var} replacing any references to @code{$(1)},
@end table @end table
Here is a summary of the automatic variables. Here is a summary of the automatic variables.
@xref{Automatic, ,Automatic Variables}, @xref{Automatic Variables},
for full information. for full information.
@table @code @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, static void record_target_var PARAMS ((struct nameseq *filenames, char *defn,
int two_colon, int two_colon,
enum variable_origin origin, enum variable_origin origin,
int enabled,
const struct floc *flocp)); const struct floc *flocp));
static enum make_word_type get_next_mword PARAMS ((char *buffer, char *delim, static enum make_word_type get_next_mword PARAMS ((char *buffer, char *delim,
char **startp, unsigned int *length)); char **startp, unsigned int *length));
@ -860,6 +861,7 @@ eval (ebuf, set_default)
{ {
enum make_word_type wtype; enum make_word_type wtype;
enum variable_origin v_origin; enum variable_origin v_origin;
int exported;
char *cmdleft, *semip, *lb_next; char *cmdleft, *semip, *lb_next;
unsigned int len, plen = 0; unsigned int len, plen = 0;
char *colonp; char *colonp;
@ -1024,17 +1026,24 @@ eval (ebuf, set_default)
p2 = variable_buffer + l; p2 = variable_buffer + l;
} }
/* See if it's an "override" keyword; if so see if what comes after /* See if it's an "override" or "export" keyword; if so see if what
it looks like a variable definition. */ comes after it looks like a variable definition. */
wtype = get_next_mword (p2, NULL, &p, &len); wtype = get_next_mword (p2, NULL, &p, &len);
v_origin = o_file; v_origin = o_file;
if (wtype == w_static && word1eq ("override")) exported = 0;
{ if (wtype == w_static)
v_origin = o_override; if (word1eq ("override"))
wtype = get_next_mword (p+len, NULL, &p, &len); {
} 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) if (wtype != w_eol)
wtype = get_next_mword (p+len, NULL, NULL, NULL); wtype = get_next_mword (p+len, NULL, NULL, NULL);
@ -1049,7 +1058,8 @@ eval (ebuf, set_default)
variable_buffer_output (p2 + strlen (p2), variable_buffer_output (p2 + strlen (p2),
semip, strlen (semip)+1); 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; filenames = 0;
continue; continue;
} }
@ -1628,11 +1638,12 @@ uniquize_deps (chain)
variable value list. */ variable value list. */
static void static void
record_target_var (filenames, defn, two_colon, origin, flocp) record_target_var (filenames, defn, two_colon, origin, exported, flocp)
struct nameseq *filenames; struct nameseq *filenames;
char *defn; char *defn;
int two_colon; int two_colon;
enum variable_origin origin; enum variable_origin origin;
int exported;
const struct floc *flocp; const struct floc *flocp;
{ {
struct nameseq *nextf; struct nameseq *nextf;
@ -1691,6 +1702,8 @@ record_target_var (filenames, defn, two_colon, origin, flocp)
if (!v) if (!v)
error (flocp, _("Malformed per-target variable definition")); error (flocp, _("Malformed per-target variable definition"));
v->per_target = 1; 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 /* If it's not an override, check to see if there was a command-line
setting. If so, reset the value. */ setting. If so, reset the value. */

5
tests/ChangeLog
View File

@ -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> 2002-10-05 Paul D. Smith <psmith@gnu.org>
* scripts/variables/automatic: Add tests for $$(@), $${@}, $${@D}, * scripts/variables/automatic: Add tests for $$(@), $${@}, $${@D},

8
tests/scripts/features/targetvars
View File

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