[llvm][ARM] Correct the properties of trap instructions

llvm/lib/Target/ARM/ARMInstrInfo.td

@@ -2378,13 +2378,13 @@ def UDF : AInoP<(outs), (ins imm0_65535:$imm16), MiscFrm, NoItinerary,
  *  - In ARM: UDF #60896;
  *  - In Thumb: UDF #254 followed by a branch-to-self.
  */
-let isBarrier = 1, isTerminator = 1 in
+let isTrap = 1 in
 def TRAPNaCl : AXI<(outs), (ins), MiscFrm, NoItinerary,
                "trap", [(trap)]>,
            Requires<[IsARM,UseNaClTrap]> {
   let Inst = 0xe7fedef0;
 }
-let isBarrier = 1, isTerminator = 1 in
+let isTrap = 1 in
 def TRAP : AXI<(outs), (ins), MiscFrm, NoItinerary,
                "trap", [(trap)]>,
            Requires<[IsARM,DontUseNaClTrap]> {

llvm/lib/Target/ARM/ARMInstrThumb.td

@@ -675,7 +675,7 @@ def tSVC : T1pI<(outs), (ins imm0_255:$imm), IIC_Br,
 }
 
 // The assembler uses 0xDEFE for a trap instruction.
-let isBarrier = 1, isTerminator = 1 in
+let isTrap = 1 in
 def tTRAP : TI<(outs), (ins), IIC_Br,
                "trap", [(trap)]>, Encoding16, Sched<[WriteBr]> {
   let Inst = 0xdefe;

llvm/test/CodeGen/ARM/trap.ll

@@ -1,3 +1,6 @@
+;; Check encodings of trap instructions and that their properties are set
+;; correctly so that they are not placed after the stack frame is destroyed.
+
 ; RUN: llc < %s -mtriple=arm-apple-darwin | FileCheck %s -check-prefix=DARWIN
 ; RUN: llc < %s -mtriple=arm-apple-darwin -trap-func=_trap | FileCheck %s -check-prefix=FUNC
 ; RUN: llc < %s -mtriple=arm-apple-darwin -trap-func=_trap -O0 | FileCheck %s -check-prefix=FUNC
@@ -29,22 +32,31 @@
 ; rdar://7961298
 ; rdar://9249183
 
-define void @t() nounwind {
+define void @t() noinline optnone {
 entry:
+  ;; So that we have a stack frame.
+  %1 = alloca i32, align 4
+  store volatile i32 0, ptr %1, align 4
+
 ; DARWIN-LABEL: t:
-; DARWIN: trap
+; DARWIN:      trap
+; DARWIN-NEXT: add sp, sp, #4
 
 ; FUNC-LABEL: t:
-; FUNC: bl __trap
+; FUNC:      bl __trap
+; FUNC-NEXT: add sp, sp, #4
 
 ; NACL-LABEL: t:
-; NACL: .inst 0xe7fedef0
+; NACL:      .inst 0xe7fedef0
+; NACL-NEXT: add sp, sp, #4
 
 ; ARM-LABEL: t:
-; ARM: .inst 0xe7ffdefe
+; ARM:      .inst 0xe7ffdefe
+; ARM-NEXT: add sp, sp, #4
 
 ; THUMB-LABEL: t:
-; THUMB: .inst.n 0xdefe
+; THUMB:      .inst.n 0xdefe
+; THUMB-NEXT: add sp, #4
 
 ; ENCODING-NACL: e7fedef0    trap
 
@@ -53,25 +65,34 @@ entry:
 ; ENCODING-THUMB: defe  trap
 
   call void @llvm.trap()
-  unreachable
+  ret void
 }
 
-define void @t2() nounwind {
+define void @t2() {
 entry:
+  ;; So that we have a stack frame.
+  %1 = alloca i32, align 4
+  store volatile i32 0, ptr %1, align 4
+
 ; DARWIN-LABEL: t2:
-; DARWIN: udf #254
+; DARWIN:      udf #254
+; DARWIN-NEXT: add sp, sp, #4
 
 ; FUNC-LABEL: t2:
-; FUNC: bl __trap
+; FUNC:      bl __trap
+; FUNC-NEXT: add sp, sp, #4
 
 ; NACL-LABEL: t2:
-; NACL: bkpt #0
+; NACL:      bkpt #0
+; NACL-NEXT: add sp, sp, #4
 
 ; ARM-LABEL: t2:
-; ARM: bkpt #0
+; ARM:      bkpt #0
+; ARM-NEXT: add sp, sp, #4
 
 ; THUMB-LABEL: t2:
-; THUMB: bkpt #0
+; THUMB:      bkpt #0
+; THUMB-NEXT: add sp, #4
 
 ; ENCODING-NACL: e1200070    bkpt #0
 
@@ -80,7 +101,7 @@ entry:
 ; ENCODING-THUMB: be00  bkpt #0
 
   call void @llvm.debugtrap()
-  unreachable
+  ret void
 }
 
 declare void @llvm.trap() nounwind