[PATCH] D42965: [ARM] Add an -arm-trap-unreachable for debugging

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
dmgreen added a reviewer: olista01.
Herald added subscribers: kristof.beyls, javed.absar, aemerson.

This adds an -arm-trap-unreachable option, similar to the hexagon
equivalent. This turns unreachable instructions into traps, which is
useful for debugging.


https://reviews.llvm.org/D42965

Files:
  lib/Target/ARM/ARMTargetMachine.cpp
  test/CodeGen/ARM/trap-unreachable.ll


Index: test/CodeGen/ARM/trap-unreachable.ll
===================================================================
--- /dev/null
+++ test/CodeGen/ARM/trap-unreachable.ll
@@ -0,0 +1,8 @@
+; RUN: llc -mtriple=thumbv7 -arm-trap-unreachable < %s | FileCheck %s
+; CHECK: .inst.n 0xdefe
+
+define void @test() #0 {
+  unreachable
+}
+
+attributes #0 = { nounwind }
Index: lib/Target/ARM/ARMTargetMachine.cpp
===================================================================
--- lib/Target/ARM/ARMTargetMachine.cpp
+++ lib/Target/ARM/ARMTargetMachine.cpp
@@ -74,6 +74,10 @@
 EnableGlobalMerge("arm-global-merge", cl::Hidden,
                   cl::desc("Enable the global merge pass"));
 
+static cl::opt<bool> EnableTrapUnreachable("arm-trap-unreachable",
+  cl::Hidden, cl::ZeroOrMore, cl::init(false),
+  cl::desc("Enable generating trap for unreachable"));
+
 namespace llvm {
   void initializeARMExecutionDomainFixPass(PassRegistry&);
 }
@@ -238,6 +242,9 @@
       this->Options.EABIVersion = EABI::EABI5;
   }
 
+  if (EnableTrapUnreachable)
+    this->Options.TrapUnreachable = true;
+
   initAsmInfo();
 }
 


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