This patch adds an option for enabling/disabling the warning for
attempting to free nonheap objects (PR/38509). The warning is
imprecise and can issue false positives.
Bootstrapped on x86-64. Ok for trunk?
Mark
2011-08-11 Mark Heffernan <meh...@google.com>
PR middle-end/38509
* common.opt (Wfree-nonheap-object): New option.
* doc/invoke.texi (Warning options): Document -Wfree-nonheap-object.
* builtins.c (maybe_emit_free_warning): Add OPT_Wfree_nonheap_object
to warning.
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 177684)
+++ gcc/doc/invoke.texi (working copy)
@@ -244,7 +244,8 @@ Objective-C and Objective-C++ Dialects}.
-Wfatal-errors -Wfloat-equal -Wformat -Wformat=2 @gol
-Wno-format-contains-nul -Wno-format-extra-args -Wformat-nonliteral @gol
-Wformat-security -Wformat-y2k @gol
--Wframe-larger-than=@var{len} -Wjump-misses-init -Wignored-qualifiers @gol
+-Wframe-larger-than=@var{len} -Wno-free-nonheap-object -Wjump-misses-init @gol
+-Wignored-qualifiers @gol
-Wimplicit -Wimplicit-function-declaration -Wimplicit-int @gol
-Winit-self -Winline -Wmaybe-uninitialized @gol
-Wno-int-to-pointer-cast -Wno-invalid-offsetof @gol
@@ -3960,6 +3961,12 @@ via @code{alloca}, variable-length array
is not included by the compiler when determining
whether or not to issue a warning.
+@item -Wno-free-nonheap-object
+@opindex Wno-free-nonheap-object
+@opindex Wfree-nonheap-object
+Do not warn when attempting to free an object which was not allocated
+on the heap.
+
@item -Wstack-usage=@var{len}
@opindex Wstack-usage
Warn if the stack usage of a function might be larger than @var{len} bytes.
Index: gcc/builtins.c
===================================================================
--- gcc/builtins.c (revision 177684)
+++ gcc/builtins.c (working copy)
@@ -6087,7 +6087,8 @@ expand_builtin (tree exp, rtx target, rt
break;
case BUILT_IN_FREE:
- maybe_emit_free_warning (exp);
+ if (warn_free_nonheap_object)
+ maybe_emit_free_warning (exp);
break;
default: /* just do library call, if unknown builtin */
@@ -11863,11 +11864,11 @@ maybe_emit_free_warning (tree exp)
return;
if (SSA_VAR_P (arg))
- warning_at (tree_nonartificial_location (exp),
- 0, "%Kattempt to free a non-heap object %qD", exp, arg);
+ warning_at (tree_nonartificial_location (exp), OPT_Wfree_nonheap_object,
+ "%Kattempt to free a non-heap object %qD", exp, arg);
else
- warning_at (tree_nonartificial_location (exp),
- 0, "%Kattempt to free a non-heap object", exp);
+ warning_at (tree_nonartificial_location (exp), OPT_Wfree_nonheap_object,
+ "%Kattempt to free a non-heap object", exp);
}
/* Fold a call to __builtin_object_size with arguments PTR and OST,
Index: gcc/common.opt
===================================================================
--- gcc/common.opt (revision 177684)
+++ gcc/common.opt (working copy)
@@ -543,6 +543,10 @@ Wframe-larger-than=
Common RejectNegative Joined UInteger
-Wframe-larger-than=<number> Warn if a function's stack frame
requires more than <number> bytes
+Wfree-nonheap-object
+Common Var(warn_free_nonheap_object) Init(1) Warning
+Warn when attempting to free a non-heap object
+
Winline
Common Var(warn_inline) Warning
Warn when an inlined function cannot be inlined
