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2010-06-29 Magnus Granberg <zorry@gentoo.org>, Kevin F. Quinn <kevquinn@gentoo.org>
* gcc/builtins.c: (expand_builtin_init_trampoline): if -Wtrampolines make a warning.
* gcc/common.opt: Add -Wtrampolines.
* gcc/doc/invoke.texi: Add -Wtrampolines.
* gcc/testsuite/gcc.dg/Wtrampolines.c: New.
--- gcc/builtins.c.zorry 2010-04-13 15:47:11.000000000 +0200
+++ gcc/builtins.c 2010-06-16 12:33:54.000000000 +0200
@@ -5150,6 +5150,11 @@
targetm.calls.trampoline_init (m_tramp, t_func, r_chain);
trampolines_created = 1;
+
+ if (warn_trampolines)
+ warning_at (DECL_SOURCE_LOCATION (t_func), OPT_Wtrampolines,
+ "trampoline generated for nested function %qD", t_func);
+
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 +192,10 @@
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 +3603,18 @@
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
+ Warn about trampolines generated for pointers to nested functions.
+
+ A trampoline is a small piece of data or code that is created at run
+ time on the stack when the address of a nested function is taken, and
+ is used to call the nested function indirectly. For some targets, it
+ is made up of data only and thus requires no special treatment. But,
+ for most targets, it is made up of code and thus requires the stack
+ to be made executable in order for the program to work properly.
+
@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 +1,56 @@
+/* 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)
+ {
+ double b (void) /* { dg-warning "trampoline generated for nested function 'b'" } */
+ {
+ 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;
+}
|
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