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[patch] Add new warning -Wtrampolines
- From: Magnus Granberg <zorry at gentoo dot org>
- To: gcc-patches at gcc dot gnu dot org
- Date: Thu, 6 May 2010 01:46:34 +0200
- Subject: [patch] Add new warning -Wtrampolines
Hi
This patch add new warning -Wtrampolines for making the compile to warn when it
generating trampoline in object that requires executable stack.
Tested on x86_64-unknown-linux-gnu and it have been in the Gentoo GCC patchset
for long time (2006).
Hardened at Gentoo.org
Magnus Granberg (Zorry) <zorry@gentoo.org>
gcc/
2010-05-06 Magnus Granberg <zorry@gentoo.org>, Kevin F. Quinn <kevquinn@gentoo.org>
* builtins.c (expand_builtin_init_trampoline): if warn_trampolines make a warning.
* common.opt: Add -Wtrampolines.
gcc/doc
2010-05-06 Magnus Granberg <zorry@gentoo.org>
* invoke.texi: Add -Wtrampolines.
gcc/testsuite/
2010-05-06 Magnus Granberg <zorry@gentoo.org>
* gcc.dg/Wtrampolines.c: New.
---
--- gcc/builtins.c.zorry 2010-04-13 15:47:11.000000000 +0200
+++ gcc/builtins.c 2010-04-25 22:45:49.000000000 +0200
@@ -5150,6 +5150,10 @@
targetm.calls.trampoline_init (m_tramp, t_func, r_chain);
trampolines_created = 1;
+
+ if (warn_trampolines)
+ warning (OPT_Wtrampolines, "generating trampoline in object (requires executable stack)");
+
return const0_rtx;
}
--- gcc/common.opt.zorry 2010-03-18 04:01:09.000000000 +0100
+++ gcc/common.opt 2010-05-06 00:44:18.000000000 +0200
@@ -192,6 +192,12 @@
Common Var(warn_system_headers) Warning
Do not suppress warnings from system headers
+
+Wtrampolines
+Common Var(warn_trampolines) Warnings
+Warn whenever a trampoline is generated
+
+
Wtype-limits
Common Var(warn_type_limits) Init(-1) Warning
Warn if a comparison is always true or always false due to the limited range of the data type
--- gcc/doc/invoke.texi.zorry 2010-04-06 16:02:22.000000000 +0200
+++ gcc/doc/invoke.texi 2010-05-06 00:20:25.000000000 +0200
@@ -258,8 +258,8 @@
-Wstrict-aliasing -Wstrict-aliasing=n @gol
-Wstrict-overflow -Wstrict-overflow=@var{n} @gol
-Wswitch -Wswitch-default -Wswitch-enum -Wsync-nand @gol
--Wsystem-headers -Wtrigraphs -Wtype-limits -Wundef -Wuninitialized @gol
--Wunknown-pragmas -Wno-pragmas @gol
+-Wsystem-headers -Wtrampolines -Wtrigraphs -Wtype-limits -Wundef @gol
+-Wuninitialized -Wunknown-pragmas -Wno-pragmas @gol
-Wunsuffixed-float-constants -Wunused -Wunused-function @gol
-Wunused-label -Wunused-parameter -Wno-unused-result -Wunused-value -Wunused-variable @gol
-Wvariadic-macros -Wvla @gol
@@ -3603,6 +3603,12 @@
option will @emph{not} warn about unknown pragmas in system
headers---for that, @option{-Wunknown-pragmas} must also be used.
+@item -Wtrampolines
+@opindex Wtrampolines
+@opindex Wno-trampolines
+Make a warning when the compiler generating trampoline in object that
+requires executable stack.
+
@item -Wfloat-equal
@opindex Wfloat-equal
@opindex Wno-float-equal
--- gcc/testsuite/gcc.dg/Wtrampolines.c.zorry 2010-05-05 12:53:11.000000000 +0200
+++ gcc/testsuite/gcc.dg/Wtrampolines.c 2010-05-06 00:26:05.000000000 +0200
@@ -0,0 +1,57 @@
+/* Origin: trampoline-1.c Waldek Hebisch <hebisch@math.uni.wroc.pl> */
+/* Ported to test -Wtrampolines Magnus Granberg <zorry@gentoo.org> */
+
+/* { dg-do compile } */
+/* { dg-require-effective-target trampolines } */
+/* { dg-options "-O2 -Wtrampolines" } */
+
+#ifndef NO_TRAMPOLINES
+
+/* This used to fail on various versions of Solaris 2 because the
+ trampoline couldn't be made executable. */
+
+extern void abort(void);
+extern double fabs(double);
+
+void foo (void)
+{
+ const int correct[1100] = {1, 0, -2, 0, 1, 0, 1, -1, -10, -30, -67};
+ int i;
+
+ double x1 (void) {return 1; }
+ double x2 (void) {return -1;}
+ double x3 (void) {return -1;}
+ double x4 (void) {return 1; }
+ double x5 (void) {return 0; }
+
+ typedef double pfun(void);
+
+ double a (int k, pfun x1, pfun x2, pfun x3, pfun x4, pfun x5) /* { dg-warning "requires executable stack" } */
+ {
+ double b (void)
+ {
+ k = k - 1;
+ return a (k, b, x1, x2, x3, x4 );
+ }
+
+ if (k <= 0)
+ return x4 () + x5 ();
+ else
+ return b ();
+ }
+
+ for (i=0; i<=10; i++)
+ {
+ if (fabs(a( i, x1, x2, x3, x4, x5 ) - correct [i]) > 0.1)
+ abort();
+ }
+}
+#endif
+
+int main (void)
+{
+#ifndef NO_TRAMPOLINES
+ foo ();
+#endif
+ return 0;
+}