1 files changed, 41 insertions, 0 deletions
diff --git a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
index 362431fd42a..a7a748b0840 100644
--- a/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
+++ b/llvm/lib/Target/Mips/MipsAsmPrinter.cpp
@@ -68,6 +68,8 @@ using namespace llvm;
 
 #define DEBUG_TYPE "mips-asm-printer"
 
+extern cl::opt<bool> EmitJalrReloc;
+
 MipsTargetStreamer &MipsAsmPrinter::getTargetStreamer() const {
   return static_cast<MipsTargetStreamer &>(*OutStreamer->getTargetStreamer());
 }
@@ -148,6 +150,40 @@ void MipsAsmPrinter::emitPseudoIndirectBranch(MCStreamer &OutStreamer,
   EmitToStreamer(OutStreamer, TmpInst0);
 }
 
+// If there is an MO_JALR operand, insert:
+//
+// .reloc tmplabel, R_{MICRO}MIPS_JALR, symbol
+// tmplabel:
+//
+// This is an optimization hint for the linker which may then replace
+// an indirect call with a direct branch.
+static void emitDirectiveRelocJalr(const MachineInstr &MI,
+                                   MCContext &OutContext,
+                                   TargetMachine &TM,
+                                   MCStreamer &OutStreamer,
+                                   const MipsSubtarget &Subtarget) {
+  for (unsigned int I = MI.getDesc().getNumOperands(), E = MI.getNumOperands();
+       I < E; ++I) {
+    MachineOperand MO = MI.getOperand(I);
+    if (MO.isMCSymbol() && (MO.getTargetFlags() & MipsII::MO_JALR)) {
+      MCSymbol *Callee = MO.getMCSymbol();
+      if (Callee && !Callee->getName().empty()) {
+        MCSymbol *OffsetLabel = OutContext.createTempSymbol();
+        const MCExpr *OffsetExpr =
+            MCSymbolRefExpr::create(OffsetLabel, OutContext);
+        const MCExpr *CaleeExpr =
+            MCSymbolRefExpr::create(Callee, OutContext);
+        OutStreamer.EmitRelocDirective
+            (*OffsetExpr,
+             Subtarget.inMicroMipsMode() ? "R_MICROMIPS_JALR" : "R_MIPS_JALR",
+             CaleeExpr, SMLoc(), *TM.getMCSubtargetInfo());
+        OutStreamer.EmitLabel(OffsetLabel);
+        return;
+      }
+    }
+  }
+}
+
 void MipsAsmPrinter::EmitInstruction(const MachineInstr *MI) {
   MipsTargetStreamer &TS = getTargetStreamer();
   unsigned Opc = MI->getOpcode();
@@ -207,6 +243,11 @@ void MipsAsmPrinter::EmitInstruction(const MachineInstr *MI) {
     return;
   }
 
+  if (EmitJalrReloc &&
+      (MI->isReturn() || MI->isCall() || MI->isIndirectBranch())) {
+    emitDirectiveRelocJalr(*MI, OutContext, TM, *OutStreamer, *Subtarget);
+  }
+
   MachineBasicBlock::const_instr_iterator I = MI->getIterator();
   MachineBasicBlock::const_instr_iterator E = MI->getParent()->instr_end();