[Hexagon] Use misaligned load instead of trap0(#0) for __builtin_trap

The trap instruction is intercepted by various runtime environments,
and instead of a crash it creates confusion.

This reapplies r354606 with a fix.

llvm-svn: 354611

1 files changed, 32 insertions, 0 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp b/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
index b0b029682bf..3ecb1428213 100644
--- a/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonInstrInfo.cpp
@@ -1313,6 +1313,38 @@ bool HexagonInstrInfo::expandPostRAPseudo(MachineInstr &MI) const {
       return true;
     }
 
+    case Hexagon::PS_crash: {
+      // Generate a misaligned load that is guaranteed to cause a crash.
+      class CrashPseudoSourceValue : public PseudoSourceValue {
+      public:
+        CrashPseudoSourceValue(const TargetInstrInfo &TII)
+          : PseudoSourceValue(TargetCustom, TII) {}
+
+        bool isConstant(const MachineFrameInfo *) const override {
+          return false;
+        }
+        bool isAliased(const MachineFrameInfo *) const override {
+          return false;
+        }
+        bool mayAlias(const MachineFrameInfo *) const override {
+          return false;
+        }
+        void printCustom(raw_ostream &OS) const override {
+          OS << "MisalignedCrash";
+        }
+      };
+
+      static const CrashPseudoSourceValue CrashPSV(*this);
+      MachineMemOperand *MMO = MF.getMachineMemOperand(
+          MachinePointerInfo(&CrashPSV),
+          MachineMemOperand::MOLoad | MachineMemOperand::MOVolatile, 8, 1);
+      BuildMI(MBB, MI, DL, get(Hexagon::PS_loadrdabs), Hexagon::D13)
+        .addImm(0xBADC0FEE)  // Misaligned load.
+        .addMemOperand(MMO);
+      MBB.erase(MI);
+      return true;
+    }
+
     case Hexagon::PS_tailcall_i:
       MI.setDesc(get(Hexagon::J2_jump));
       return true;