The argument to EnabledBy() must be one or more options with the
Common flag, otherwise the setting is silently ignored. This patch
detects this case when generating the options.c file and gives an
appropriate error. There were two options suffering from this: -Wchkp
is fixed by using LangEnabledBy instead, but -Wnull-dereference cannot
be enabled by -Wall or -Wextra because it triggers false positives
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=16351#c35)
Bootstrapped and regression tested on x86_64-linux-gnu.
OK?
gcc/ChangeLog:
2015-08-08 Manuel López-Ibáñez <m...@gcc.gnu.org>
* doc/invoke.texi (Wnull-dereference): Move after Wnonnull.
Not enabled by -Wall.
* optc-gen.awk: Give nicer error messages. Detect if the argument
of EnabledBy is not a Common option.
* common.opt (Wnull-dereference): Not enabled by -Wall.
* opt-functions.awk (lang_enabled_by): Nicer error messages.
gcc/c-family/ChangeLog:
2015-08-08 Manuel López-Ibáñez <m...@gcc.gnu.org>
* c.opt (Wchkp): Use LangEnabledBy instead of EnabledBy.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 226719)
+++ gcc/doc/invoke.texi (working copy)
@@ -3720,10 +3720,19 @@ Warn about passing a null pointer for ar
requiring a non-null value by the @code{nonnull} function attribute.
@option{-Wnonnull} is included in @option{-Wall} and @option{-Wformat}. It
can be disabled with the @option{-Wno-nonnull} option.
+@item -Wnull-dereference
+@opindex Wnull-dereference
+@opindex Wno-null-dereference
+Warn if the compiler detects paths that trigger erroneous or
+undefined behavior due to dereferencing a null pointer. This option
+is only active when @option{-fdelete-null-pointer-checks} is active,
+which is enabled by optimizations in most targets. The precision of
+the warnings depends on the optimization options used.
+
@item -Winit-self @r{(C, C++, Objective-C and Objective-C++ only)}
@opindex Winit-self
@opindex Wno-init-self
Warn about uninitialized variables that are initialized with themselves.
Note this option can only be used with the @option{-Wuninitialized} option.
@@ -4156,20 +4165,10 @@ All the above @option{-Wunused} options
In order to get a warning about an unused function parameter, you must
either specify @option{-Wextra -Wunused} (note that @option{-Wall} implies
@option{-Wunused}), or separately specify @option{-Wunused-parameter}.
-@item -Wnull-dereference
-@opindex Wnull-dereference
-@opindex Wno-null-dereference
-Warn if the compiler detects paths that trigger erroneous or
-undefined behavior due to dereferencing a null pointer. This option
-is only active when @option{-fdelete-null-pointer-checks} is active,
-which is enabled by optimizations in most targets. The precision of
-the warnings depends on the optimization options used. This option is
-enabled by @option{-Wall}.
-
@item -Wuninitialized
@opindex Wuninitialized
@opindex Wno-uninitialized
Warn if an automatic variable is used without first being initialized
or if a variable may be clobbered by a @code{setjmp} call. In C++,
Index: gcc/c-family/c.opt
===================================================================
--- gcc/c-family/c.opt (revision 226719)
+++ gcc/c-family/c.opt (working copy)
@@ -333,11 +333,11 @@ Warn about casts which discard qualifier
Wchar-subscripts
C ObjC C++ ObjC++ Var(warn_char_subscripts) Warning LangEnabledBy(C ObjC C++
ObjC++,Wall)
Warn about subscripts whose type is \"char\"
Wchkp
-C ObjC C++ ObjC++ Var(warn_chkp) Warning EnabledBy(Wall)
+C ObjC C++ ObjC++ Var(warn_chkp) Warning LangEnabledBy(C ObjC C++ ObjC++,Wall)
Warn about memory access errors found by Pointer Bounds Checker
Wclobbered
C ObjC C++ ObjC++ Var(warn_clobbered) Warning EnabledBy(Wextra)
Warn about variables that might be changed by \"longjmp\" or \"vfork\"
Index: gcc/optc-gen.awk
===================================================================
--- gcc/optc-gen.awk (revision 226719)
+++ gcc/optc-gen.awk (working copy)
@@ -28,11 +28,25 @@
# [-v header_name=header.h] < inputfile > options.c
# Dump that array of options into a C file.
END {
-# Record first EnabledBy and LangEnabledBy uses.
+
+# Combine the flags of identical switches. Switches
+# appear many times if they are handled by many front
+# ends, for example.
+for (i = 0; i < n_opts; i++) {
+ merged_flags[i] = flags[i]
+}
+for (i = 0; i < n_opts; i++) {
+ while(i + 1 != n_opts && opts[i] == opts[i + 1] ) {
+ merged_flags[i + 1] = merged_flags[i] " " merged_flags[i + 1];
+ i++;
+ }
+}
+
+# Record EnabledBy and LangEnabledBy uses.
n_enabledby = 0;
for (i = 0; i < n_langs; i++) {
n_enabledby_lang[i] = 0;
}
for (i = 0; i < n_opts; i++) {
@@ -46,19 +60,23 @@ for (i = 0; i < n_opts; i++) {
# EnabledBy(arg) or EnabledBy(arg1 || arg2 || arg3)
split_sep = " \\|\\| ";
}
n_enabledby_names = split(enabledby_arg, enabledby_names, split_sep);
if (logical_and != 0 && n_enabledby_names > 2) {
- print "#error EnabledBy (Wfoo && Wbar && Wbaz) not currently
supported"
+ print "#error " opts[i] " EnabledBy(Wfoo && Wbar && Wbaz)
currently not supported"
}
for (j = 1; j <= n_enabledby_names; j++) {
enabledby_name = enabledby_names[j];
enabledby_index = opt_numbers[enabledby_name];
if (enabledby_index == "") {
- print "#error Enabledby: " enabledby_name
- } else {
- condition = "";
+ print "#error " opts[i] " Enabledby(" enabledby_name "),
unknown option '" enabledby_name "'"
+ } else if (!flag_set_p("Common", merged_flags[enabledby_index])) {
+ print "#error " opts[i] " Enabledby(" enabledby_name "), '" \
+ enabledby_name "' must have flag 'Common'" \
+ " to use Enabledby(), otherwise use LangEnabledBy()"
+ } else {
+ condition = "";
if (logical_and != 0) {
opt_var_name_1 = search_var_name(enabledby_names[1],
opt_numbers, opts, flags, n_opts);
opt_var_name_2 = search_var_name(enabledby_names[2],
opt_numbers, opts, flags, n_opts);
if (opt_var_name_1 == "") {
print "#error " enabledby_names[1] " does not have a
Var() flag"
Index: gcc/common.opt
===================================================================
--- gcc/common.opt (revision 226719)
+++ gcc/common.opt (working copy)
@@ -591,11 +591,11 @@ Common RejectNegative Joined Warning Und
Wlarger-than=
Common RejectNegative Joined UInteger Warning
-Wlarger-than=<number> Warn if an object is larger than <number> bytes
Wnull-dereference
-Common Var(warn_null_dereference) Warning EnabledBy(Wall)
+Common Var(warn_null_dereference) Warning
Warn if dereferencing a NULL pointer may lead to erroneous or undefined
behavior
Wunsafe-loop-optimizations
Common Var(warn_unsafe_loop_optimizations) Warning
Warn if the loop cannot be optimized due to nontrivial assumptions.
Index: gcc/opt-functions.awk
===================================================================
--- gcc/opt-functions.awk (revision 226719)
+++ gcc/opt-functions.awk (working copy)
@@ -322,21 +322,21 @@ function lang_enabled_by(enabledby_langs
if (enabledby_posarg != "" && enabledby_negarg != "") {
with_args = "," enabledby_posarg "," enabledby_negarg
} else if (enabledby_posarg == "" && enabledby_negarg == "") {
with_args = ""
} else {
- print "#error LangEnabledBy("enabledby_langs","enabledby_name", " \
+ print "#error " opts[i] "
LangEnabledBy("enabledby_langs","enabledby_name", " \
enabledby_posarg", " enabledby_negargs \
") with three arguments, it should have either 2 or 4"
}
n_enabledby_array = split(enabledby_name, enabledby_array, " \\|\\| ");
for (k = 1; k <= n_enabledby_array; k++) {
enabledby_index = opt_numbers[enabledby_array[k]];
if (enabledby_index == "") {
- print "#error LangEnabledBy("enabledby_langs","enabledby_name", "
\
- enabledby_posarg", " enabledby_negargs") has invalid
ENABLEDBY_NAME"
+ print "#error " opts[i] "
LangEnabledBy("enabledby_langs","enabledby_name", " \
+ enabledby_posarg", " enabledby_negargs"), unknown option '"
enabledby_name "'"
} else {
for (j = 1; j <= n_enabledby_arg_langs; j++) {
lang_name = lang_sanitized_name(enabledby_arg_langs[j]);
lang_index = lang_numbers[enabledby_arg_langs[j]];
if (enables[lang_name,enabledby_array[k]] == "") {
