This patch adds documentation on the -gnato? and -gnato?? switches
to the usage information. Documentation only, no functional effect
but gnatmake output (with no switches) should have the following
three lines for -gnato:
-gnato Enable overflow checking mode to CHECKED (off by default)
-gnato? Set SUPPRESSED/CHECKED/MINIMIZED/ELIMINATED (?=0/1/2/3) mode
-gnato?? Set mode for general/assertion expressions separately
Tested on x86_64-pc-linux-gnu, committed on trunk
2012-10-02 Robert Dewar <de...@adacore.com>
* usage.adb, gnat_rm.texi, vms_data.ads: Add entry for
/OVERFLOW_CHECKS=?? generating -gnato?? for control
of extended overflow checking.
* ug_words: Add entry for -gnato?? for /OVERFLOW_CHECKS=??
* gnat_ugn.texi: Add documentation for -gnato?? for control of overflow
checking mode.
Index: gnat_rm.texi
===================================================================
--- gnat_rm.texi (revision 191888)
+++ gnat_rm.texi (working copy)
@@ -179,6 +179,7 @@
* Pragma Obsolescent::
* Pragma Optimize_Alignment::
* Pragma Ordered::
+* Pragma Overflow_Checks::
* Pragma Passive::
* Pragma Persistent_BSS::
* Pragma Polling::
@@ -916,6 +917,7 @@
* Pragma Obsolescent::
* Pragma Optimize_Alignment::
* Pragma Ordered::
+* Pragma Overflow_Checks::
* Pragma Passive::
* Pragma Persistent_BSS::
* Pragma Polling::
@@ -4127,6 +4129,53 @@
For additional information please refer to the description of the
@option{-gnatw.u} switch in the @value{EDITION} User's Guide.
+@node Pragma Overflow_Checks
+@unnumberedsec Pragma Overflow_Checks
+@findex Overflow checks
+@findex pragma @code{Overflow_Checks}
+@noindent
+Syntax:
+
+@smallexample @c ada
+pragma Overflow_Checks
+ ( [General =>] MODE
+ [,[Assertions =>] MODE]);
+
+MODE ::= SUPPRESSED | CHECKED | MINIMIZED | ELIMINATED
+@end smallexample
+
+@noindent
+This pragma sets the current overflow mode to the given mode. For details
+of the meaning of these modes, see section on overflow checking in the
+GNAT users guide. If only the @code{General} parameter is present, the
+given mode applies to all expressions. If both parameters are present,
+the @code{General} mode applies to expressions outside assertions, and
+the @code{Eliminated} mode applies to expressions within assertions.
+
+The case of the @code{MODE} parameter is ignored,
+so @code{MINIMIZED}, @code{Minimized} and
+@code{minimized} all have the same effect.
+
+The @code{Overflow_Checks} pragma has the same scoping and placement
+rules as pragma @code{Suppress}, so it can occur either as a
+configuration pragma, specifying a default for the whole
+program, or in a declarative scope, where it applies to the
+remaining declarations and statements in that scope.
+
+The pragma @code{Suppress (Overflow_Check)} sets mode
+
+ General => Suppressed
+
+suppressing all overflow checking within and outside
+assertions.
+
+The pragam @code{Unsuppress (Overflow_Check)} sets mode
+
+ General => Checked
+
+which causes overflow checking of all intermediate overflows.
+This applies both inside and outside assertions.
+
@node Pragma Passive
@unnumberedsec Pragma Passive
@findex Passive
Index: gnat_ugn.texi
===================================================================
--- gnat_ugn.texi (revision 191910)
+++ gnat_ugn.texi (working copy)
@@ -4325,11 +4325,28 @@
Historically front end inlining was more extensive than the gcc back end
inlining, but that is no longer the case.
+@item -gnato??
+@cindex @option{-gnato??} (@command{gcc})
+Set default overflow cheecking mode. If ?? is a single digit, in the
+range 0-3, it sets the overflow checking mode for all expressions,
+including those outside and within assertions. The meaning of nnn is:
+
+ 0 suppress overflow checks (SUPPRESSED)
+ 1 all intermediate overflows checked (CHECKED)
+ 2 minimize intermediate overflows (MINIMIZED)
+ 3 eliminate intermediate overflows (ELIMINATED)
+
+Otherwise ?? can be two digits, both 0-3, and in this case the first
+digit sets the mode (using the above code) for expressions outside an
+assertion, and the second digit sets the mode for expressions within
+an assertion.
+
@item -gnato
@cindex @option{-gnato} (@command{gcc})
Enable numeric overflow checking (which is not normally enabled by
default). Note that division by zero is a separate check that is not
controlled by this switch (division by zero checking is on by default).
+The checking mode is set to CHECKED (equivalent to @option{-gnato11}).
@item -gnatp
@cindex @option{-gnatp} (@command{gcc})
Index: ug_words
===================================================================
--- ug_words (revision 191888)
+++ ug_words (working copy)
@@ -88,6 +88,7 @@
-gnatn2 ^ /INLINE=PRAGMA_LEVEL_2
-gnatN ^ /INLINE=FULL
-gnato ^ /CHECKS=OVERFLOW
+-gnato?? ^ /OVERFLOW_CHECKS=??
-gnatp ^ /CHECKS=SUPPRESS_ALL
-gnat-p ^ /CHECKS=UNSUPPRESS_ALL
-gnatP ^ /POLLING
Index: usage.adb
===================================================================
--- usage.adb (revision 191900)
+++ usage.adb (working copy)
@@ -319,8 +319,16 @@
-- Line for -gnato switch
Write_Switch_Char ("o");
- Write_Line ("Enable overflow checking (off by default)");
+ Write_Line ("Enable overflow checking mode to CHECKED (off by default)");
+ -- Line for -gnato? switch
+
+ Write_Switch_Char ("o?");
+ Write_Line ("Set SUPPRESSED/CHECKED/MINIMIZED/ELIMINATED (?=0/1/2/3) mode");
+
+ Write_Switch_Char ("o??");
+ Write_Line ("Set mode for general/assertion expressions separately");
+
-- Line for -gnatO switch
Write_Switch_Char ("O nm ");
Index: vms_data.ads
===================================================================
--- vms_data.ads (revision 191888)
+++ vms_data.ads (working copy)
@@ -1347,12 +1347,13 @@
-- if the /CHECKS qualifier is not present on the
-- command line. Same as /NOCHECKS.
--
- -- OVERFLOW Enables overflow checking for integer operations and
- -- checks for access before elaboration on subprogram
- -- calls. This causes GNAT to generate slower and larger
- -- executable programs by adding code to check for both
- -- overflow and division by zero (resulting in raising
- -- "Constraint_Error" as required by Ada semantics).
+ -- OVERFLOW Enables overflow checking in CHECKED mode for integer
+ -- operations and checks for access before elaboration
+ -- on subprogram calls. This causes GNAT to generate
+ -- slower and larger executable programs by adding code
+ -- to check for both overflow and division by zero
+ -- (resulting in raising "Constraint_Error" as required
+ -- by Ada semantics).
-- Similarly, GNAT does not generate elaboration check
-- by default, and you must specify this keyword to
-- enable them.
@@ -2108,6 +2109,24 @@
-- file xyz.adb is compiled with -gnatl=.lst, then the output is written
-- to file xyz.adb_lst.
+ S_GCC_Overflo : aliased constant S := "/OVERFLOW_CHECKS=#" &
+ "-gnato#";
+ -- /OVERFLOW_CHECKS=nn
+ --
+ -- Set default overflow cheecking mode. If nn is a single digit, in the
+ -- range 0-3, it sets the overflow checking mode for all expressions,
+ -- including those outside and within assertions. The meaning of nnn is:
+ --
+ -- 0 suppress overflow checks (SUPPRESSED)
+ -- 1 all intermediate overflows checked (CHECKED)
+ -- 2 minimize intermediate overflows (MINIMIZED)
+ -- 3 eliminate intermediate overflows (ELIMINATED)
+ --
+ -- Otherwise nn can be two digits, both 0-3, and in this case the first
+ -- digit sets the mode (using the above code) for expressions outside an
+ -- assertion, and the second digit sets the mode for expressions within
+ -- an assertion.
+
S_GCC_Pointer : aliased constant S := "/POINTER_SIZE=" &
"64 " &
"-mmalloc64 " &
@@ -3622,6 +3641,7 @@
S_GCC_NoWarnP 'Access,
S_GCC_Opt 'Access,
S_GCC_OptX 'Access,
+ S_GCC_Overflo 'Access,
S_GCC_Pointer 'Access,
S_GCC_Polling 'Access,
S_GCC_Project 'Access,
