This patch is to fix radar://8426430. It is about llvm support of __builtin_debugtrap()

which is supposed to consistently raise SIGTRAP across all systems. In contrast,
__builtin_trap() behave differently on different systems. e.g. it raises SIGTRAP on ARM, and
SIGILL on X86. The purpose of __builtin_debugtrap() is to consistently provide "trap"
functionality, in the mean time preserve the compatibility with on gcc on __builtin_trap().

  The X86 backend is already able to handle debugtrap(). This patch is to:
  1) make front-end recognize "__builtin_debugtrap()" (emboddied in the one-line change to Clang).
  2) In DAG legalization phase, by default, "debugtrap" will be replaced with "trap", which
     make the __builtin_debugtrap() "available" to all existing ports without the hassle of
     changing their code.
  3) If trap-function is specified (via -trap-func=xyz to llc), both __builtin_debugtrap() and
     __builtin_trap() will be expanded into the function call of the specified trap function.
    This behavior may need change in the future.

  The provided testing-case is to make sure 2) and 3) are working for ARM port, and we
already have a testing case for x86. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166300 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 5 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index cdebff94e5..db15994174 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5175,10 +5175,13 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     return 0;
   }
 
+  case Intrinsic::debugtrap:
   case Intrinsic::trap: {
     StringRef TrapFuncName = TM.Options.getTrapFunctionName();
     if (TrapFuncName.empty()) {
-      DAG.setRoot(DAG.getNode(ISD::TRAP, dl,MVT::Other, getRoot()));
+      ISD::NodeType Op = (Intrinsic == Intrinsic::trap) ? 
+        ISD::TRAP : ISD::DEBUGTRAP;
+      DAG.setRoot(DAG.getNode(Op, dl,MVT::Other, getRoot()));
       return 0;
     }
     TargetLowering::ArgListTy Args;
@@ -5193,10 +5196,7 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     DAG.setRoot(Result.second);
     return 0;
   }
-  case Intrinsic::debugtrap: {
-    DAG.setRoot(DAG.getNode(ISD::DEBUGTRAP, dl,MVT::Other, getRoot()));
-    return 0;
-  }
+
   case Intrinsic::uadd_with_overflow:
   case Intrinsic::sadd_with_overflow:
   case Intrinsic::usub_with_overflow: