> > Hi,
> >
> > Currently, on ARM, you have to either call abort() or raise(SIGTRAP)
> > to achieve a handy crash.
> >
> > This patch allows you to instead call __builtin_trap() which is much
> > more efficient at falling over because it becomes just a single
> > instruction that will trap for you.
> >
> > Two testcases have been added (for ARM and Thumb) and both pass.
> >
> >
> > Note: This is a modified version of a patch originally submitted by
> Mark
> > Mitchell back in 2010, which came in response to PR target/59091.
> >
> > http://gcc.gnu.org/ml/gcc-patches/2010-09/msg00639.html
> > http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59091
> >
> > The main update, other than cosmetic differences, is that we've
> chosen
> > the same ARM encoding as LLVM for practical purposes. (The Thumb
> > encoding in Mark's patch already matched LLVM.)
> >
> >
> > OK for trunk?
> >
> > Cheers,
> > Ian
> >
> >
> > 2013-12-04 Ian Bolton <[email protected]>
> > Mark Mitchell <[email protected]>
> >
> > gcc/
> > * config/arm/arm.md (trap): New pattern.
> > * config/arm/types.md: Added a type for trap.
> >
> > testsuite/
> > * gcc.target/arm/builtin-trap.c: New test.
> > * gcc.target/arm/thumb-builtin-trap.c: Likewise.
> > <aarch32-builtin-trap-v2.txt>
>
> This needs to set the conds attribute to "unconditional". Otherwise
> the ARM backend might try to turn this into a conditional instruction.
>
> R.
Thanks, Richard. I fixed it up, tested it and committed as trivial
difference compared to what was approved already.
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index dd73366..934b859 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -9927,6 +9927,23 @@
(set_attr "type" "mov_reg")]
)
+(define_insn "trap"
+ [(trap_if (const_int 1) (const_int 0))]
+ ""
+ "*
+ if (TARGET_ARM)
+ return \".inst\\t0xe7f000f0\";
+ else
+ return \".inst\\t0xdeff\";
+ "
+ [(set (attr "length")
+ (if_then_else (eq_attr "is_thumb" "yes")
+ (const_int 2)
+ (const_int 4)))
+ (set_attr "type" "trap")
+ (set_attr "conds" "unconditional")]
+)
+
;; Patterns to allow combination of arithmetic, cond code and shifts
diff --git a/gcc/config/arm/types.md b/gcc/config/arm/types.md
index 1c4b9e3..6351f08 100644
--- a/gcc/config/arm/types.md
+++ b/gcc/config/arm/types.md
@@ -152,6 +152,7 @@
; store2 store 2 words to memory from arm registers.
; store3 store 3 words to memory from arm registers.
; store4 store 4 (or more) words to memory from arm registers.
+; trap cause a trap in the kernel.
; udiv unsigned division.
; umaal unsigned multiply accumulate accumulate long.
; umlal unsigned multiply accumulate long.
@@ -645,6 +646,7 @@
store2,\
store3,\
store4,\
+ trap,\
udiv,\
umaal,\
umlal,\
diff --git a/gcc/testsuite/gcc.target/arm/builtin-trap.c
b/gcc/testsuite/gcc.target/arm/builtin-trap.c
new file mode 100644
index 0000000..4ff8d25
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/builtin-trap.c
@@ -0,0 +1,10 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target arm32 } */
+
+void
+trap ()
+{
+ __builtin_trap ();
+}
+
+/* { dg-final { scan-assembler "0xe7f000f0" { target { arm_nothumb } } } } */
diff --git a/gcc/testsuite/gcc.target/arm/thumb-builtin-trap.c
b/gcc/testsuite/gcc.target/arm/thumb-builtin-trap.c
new file mode 100644
index 0000000..22e90e7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/thumb-builtin-trap.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-mthumb" } */
+/* { dg-require-effective-target arm_thumb1_ok } */
+
+void
+trap ()
+{
+ __builtin_trap ();
+}
+
+/* { dg-final { scan-assembler "0xdeff" } } */
