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 <ian.bol...@arm.com>
Mark Mitchell <m...@codesourcery.com>
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.
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index dd73366..3b7a827 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -9927,6 +9927,22 @@
(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")]
+)
+
;; 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" } } */
