[llvm] r345171 - ARM: Use BKPT instead of TRAP to implement llvm.debugtrap.
Peter Collingbourne via llvm-commits
llvm-commits at lists.llvm.org
Wed Oct 24 11:10:38 PDT 2018
Author: pcc
Date: Wed Oct 24 11:10:38 2018
New Revision: 345171
URL: http://llvm.org/viewvc/llvm-project?rev=345171&view=rev
Log:
ARM: Use BKPT instead of TRAP to implement llvm.debugtrap.
The BKPT instruction is specified to cause a software breakpoint,
and at least on Linux results in a SIGTRAP. This makes it more
suitable for implementing debugtrap than TRAP (aka UDF #254), which
is specified to cause an undefined instruction exception and results
in a SIGILL on Linux.
Moreover, BKPT is not marked as a terminator, which is not only
consistent with the IR instruction but allows the analyzeBlock
function to correctly analyze a basic block containing the instruction,
which fixes an assertion failure in the machine block placement pass
previously triggered by the included test case.
Because BKPT is only supported starting with ARMv5T, we continue to
use UDF #254 when targeting v4T.
Differential Revision: https://reviews.llvm.org/D53614
Added:
llvm/trunk/test/CodeGen/ARM/analyze-branch-bkpt.ll
Modified:
llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
llvm/trunk/lib/Target/ARM/ARMInstrThumb.td
llvm/trunk/test/CodeGen/ARM/debugtrap.ll
llvm/trunk/test/CodeGen/ARM/trap.ll
Modified: llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp?rev=345171&r1=345170&r2=345171&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMISelLowering.cpp Wed Oct 24 11:10:38 2018
@@ -956,6 +956,7 @@ ARMTargetLowering::ARMTargetLowering(con
setOperationAction(ISD::BlockAddress, MVT::i32, Custom);
setOperationAction(ISD::TRAP, MVT::Other, Legal);
+ setOperationAction(ISD::DEBUGTRAP, MVT::Other, Legal);
// Use the default implementation.
setOperationAction(ISD::VASTART, MVT::Other, Custom);
Modified: llvm/trunk/lib/Target/ARM/ARMInstrInfo.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrInfo.td?rev=345171&r1=345170&r2=345171&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrInfo.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMInstrInfo.td Wed Oct 24 11:10:38 2018
@@ -221,6 +221,7 @@ def HasV4T : Predicate<"Subtar
def NoV4T : Predicate<"!Subtarget->hasV4TOps()">;
def HasV5T : Predicate<"Subtarget->hasV5TOps()">,
AssemblerPredicate<"HasV5TOps", "armv5t">;
+def NoV5T : Predicate<"!Subtarget->hasV5TOps()">;
def HasV5TE : Predicate<"Subtarget->hasV5TEOps()">,
AssemblerPredicate<"HasV5TEOps", "armv5te">;
def HasV6 : Predicate<"Subtarget->hasV6Ops()">,
@@ -2200,6 +2201,9 @@ def TRAP : AXI<(outs), (ins), MiscFrm, N
let Inst = 0xe7ffdefe;
}
+def : Pat<(debugtrap), (BKPT 0)>, Requires<[IsARM, HasV5T]>;
+def : Pat<(debugtrap), (UDF 254)>, Requires<[IsARM, NoV5T]>;
+
// Address computation and loads and stores in PIC mode.
let isNotDuplicable = 1 in {
def PICADD : ARMPseudoInst<(outs GPR:$dst), (ins GPR:$a, pclabel:$cp, pred:$p),
Modified: llvm/trunk/lib/Target/ARM/ARMInstrThumb.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMInstrThumb.td?rev=345171&r1=345170&r2=345171&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMInstrThumb.td (original)
+++ llvm/trunk/lib/Target/ARM/ARMInstrThumb.td Wed Oct 24 11:10:38 2018
@@ -1380,6 +1380,9 @@ def tUDF : TI<(outs), (ins imm0_255:$imm
let Inst{7-0} = imm8;
}
+def : Pat<(debugtrap), (tBKPT 0)>, Requires<[IsThumb, HasV5T]>;
+def : Pat<(debugtrap), (tUDF 254)>, Requires<[IsThumb, NoV5T]>;
+
def t__brkdiv0 : TI<(outs), (ins), IIC_Br, "__brkdiv0",
[(int_arm_undefined 249)]>, Encoding16,
Requires<[IsThumb, IsWindows]> {
Added: llvm/trunk/test/CodeGen/ARM/analyze-branch-bkpt.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/analyze-branch-bkpt.ll?rev=345171&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/analyze-branch-bkpt.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/analyze-branch-bkpt.ll Wed Oct 24 11:10:38 2018
@@ -0,0 +1,61 @@
+; RUN: llc -o - %s -mtriple thumbv4-unknown-linux-android | FileCheck --check-prefix=V4 %s
+; RUN: llc -o - %s -mtriple thumbv5-unknown-linux-android | FileCheck --check-prefix=V5 %s
+
+; V4: udf #254
+; V5: bkpt #0
+
+define i1 @a(i32 %b) !dbg !3 {
+ br i1 undef, label %c, label %d, !dbg !4
+
+d: ; preds = %0
+ call void @llvm.debugtrap()
+ br label %ah, !dbg !4
+
+c: ; preds = %0
+ %aj = icmp ne i20 undef, 5
+ br label %ah, !dbg !4
+
+ah: ; preds = %c, %d
+ %ak = phi i1 [ false, %d ], [ %aj, %c ]
+ call void @llvm.dbg.value(metadata i1 %ak, metadata !7, metadata !DIExpression()), !dbg !9
+ switch i32 %b, label %al [
+ i32 0, label %am
+ i32 10, label %an
+ ]
+
+an: ; preds = %ah
+ %ch = select i1 %ak, i32 0, i32 5
+ br label %am, !dbg !10
+
+al: ; preds = %ah
+ br label %am, !dbg !9
+
+am: ; preds = %al, %an, %ah
+ %1 = phi i32 [ 0, %al ], [ %ch, %an ], [ %b, %ah ]
+ unreachable
+}
+
+; Function Attrs: nounwind readnone speculatable
+declare void @llvm.dbg.value(metadata, metadata, metadata) #0
+
+; Function Attrs: nounwind
+declare void @llvm.debugtrap() #1
+
+attributes #0 = { nounwind readnone speculatable }
+attributes #1 = { nounwind }
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, isOptimized: false, runtimeVersion: 0, emissionKind: NoDebug)
+!1 = !DIFile(filename: "a", directory: "")
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
+!4 = !DILocation(line: 0, scope: !5, inlinedAt: !6)
+!5 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
+!6 = !DILocation(line: 0, scope: !3)
+!7 = !DILocalVariable(scope: !8)
+!8 = distinct !DISubprogram(scope: null, isLocal: false, isDefinition: true, isOptimized: false, unit: !0)
+!9 = !DILocation(line: 0, scope: !8, inlinedAt: !6)
+!10 = !DILocation(line: 0, scope: !11, inlinedAt: !6)
+!11 = !DILexicalBlock(scope: !8)
Modified: llvm/trunk/test/CodeGen/ARM/debugtrap.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/debugtrap.ll?rev=345171&r1=345170&r2=345171&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/debugtrap.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/debugtrap.ll Wed Oct 24 11:10:38 2018
@@ -1,7 +1,10 @@
; This test ensures the @llvm.debugtrap() call is not removed when generating
; the 'pop' instruction to restore the callee saved registers on ARM.
-; RUN: llc < %s -mtriple=armv7 -O0 -filetype=asm | FileCheck %s
+; RUN: llc < %s -mtriple=armv4 -O0 -filetype=asm | FileCheck --check-prefixes=CHECK,V4 %s
+; RUN: llc < %s -mtriple=armv5 -O0 -filetype=asm | FileCheck --check-prefixes=CHECK,V5 %s
+; RUN: llc < %s -mtriple=thumbv4 -O0 -filetype=asm | FileCheck --check-prefixes=CHECK,V4 %s
+; RUN: llc < %s -mtriple=thumbv5 -O0 -filetype=asm | FileCheck --check-prefixes=CHECK,V5 %s
declare void @llvm.debugtrap() nounwind
declare void @foo() nounwind
@@ -9,8 +12,9 @@ declare void @foo() nounwind
define void @test() nounwind {
entry:
; CHECK: bl foo
+ ; V4-NEXT: udf #254
+ ; V5-NEXT: bkpt #0
; CHECK-NEXT: pop
- ; CHECK-NEXT: .inst 0xe7ffdefe
call void @foo()
call void @llvm.debugtrap()
ret void
Modified: llvm/trunk/test/CodeGen/ARM/trap.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/trap.ll?rev=345171&r1=345170&r2=345171&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/trap.ll (original)
+++ llvm/trunk/test/CodeGen/ARM/trap.ll Wed Oct 24 11:10:38 2018
@@ -59,25 +59,25 @@ entry:
define void @t2() nounwind {
entry:
; DARWIN-LABEL: t2:
-; DARWIN: trap
+; DARWIN: udf #254
; FUNC-LABEL: t2:
; FUNC: bl __trap
; NACL-LABEL: t2:
-; NACL: .inst 0xe7fedef0
+; NACL: bkpt #0
; ARM-LABEL: t2:
-; ARM: .inst 0xe7ffdefe
+; ARM: bkpt #0
; THUMB-LABEL: t2:
-; THUMB: .inst.n 0xdefe
+; THUMB: bkpt #0
-; ENCODING-NACL: f0 de fe e7 trap
+; ENCODING-NACL: 70 00 20 e1 bkpt #0
-; ENCODING-ARM: fe de ff e7 trap
+; ENCODING-ARM: 70 00 20 e1 bkpt #0
-; ENCODING-THUMB: fe de trap
+; ENCODING-THUMB: 00 be bkpt #0
call void @llvm.debugtrap()
unreachable
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