[SystemZ] Add support for fentry.

SystemZAsmPrinter now properly emits function calls to __fentry__.

Review: Ulrich Weigand
llvm-svn: 370743

2 files changed, 15 insertions, 0 deletions

diff --git a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp
index ef378e4ade7..f03ed2014e4 100644
--- a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.cpp
@@ -501,6 +501,10 @@ void SystemZAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     }
     break;
 
+  case TargetOpcode::FENTRY_CALL:
+    LowerFENTRY_CALL(*MI, Lower);
+    return;
+
   case TargetOpcode::STACKMAP:
     LowerSTACKMAP(*MI);
     return;
@@ -546,6 +550,16 @@ static unsigned EmitNop(MCContext &OutContext, MCStreamer &OutStreamer,
   }
 }
 
+void SystemZAsmPrinter::LowerFENTRY_CALL(const MachineInstr &MI,
+                                         SystemZMCInstLower &Lower) {
+  MCContext &Ctx = MF->getContext();
+  MCSymbol *fentry = Ctx.getOrCreateSymbol("__fentry__");
+  const MCSymbolRefExpr *Op =
+      MCSymbolRefExpr::create(fentry, MCSymbolRefExpr::VK_PLT, Ctx);
+  OutStreamer->EmitInstruction(MCInstBuilder(SystemZ::BRASL)
+                       .addReg(SystemZ::R0D).addExpr(Op), getSubtargetInfo());
+}
+
 void SystemZAsmPrinter::LowerSTACKMAP(const MachineInstr &MI) {
   const SystemZInstrInfo *TII =
     static_cast<const SystemZInstrInfo *>(MF->getSubtarget().getInstrInfo());
diff --git a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h
index aa5d3ca78e6..d01a17c2ebe 100644
--- a/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h
+++ b/llvm/lib/Target/SystemZ/SystemZAsmPrinter.h
@@ -46,6 +46,7 @@ public:
   }
 
 private:
+  void LowerFENTRY_CALL(const MachineInstr &MI, SystemZMCInstLower &MCIL);
   void LowerSTACKMAP(const MachineInstr &MI);
   void LowerPATCHPOINT(const MachineInstr &MI, SystemZMCInstLower &Lower);
 };