[mips] Emit .reloc R_{MICRO}MIPS_JALR along with j(al)r(c) $25

The callee address is added as an optional operand (MCSymbol) in
AdjustInstrPostInstrSelection() and then used by asm printer to insert:
'.reloc tmplabel, R_MIPS_JALR, symbol
tmplabel:'.
Controlled with '-mips-jalr-reloc', default is true.

Differential revision: https://reviews.llvm.org/D56694

llvm-svn: 351485

13 files changed, 147 insertions, 11 deletions

diff --git a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
index d2fed686147..f10d100bfe1 100644
--- a/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
+++ b/llvm/lib/Target/Mips/AsmParser/MipsAsmParser.cpp
@@ -65,10 +65,7 @@ class MCInstrInfo;
 
 } // end namespace llvm
 
-static cl::opt<bool>
-EmitJalrReloc("mips-jalr-reloc", cl::Hidden,
-              cl::desc("MIPS: Emit R_{MICRO}MIPS_JALR relocation with jalr"),
-              cl::init(true));
+extern cl::opt<bool> EmitJalrReloc;
 
 namespace {
 
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp
index 18d7dd99be3..2f2dd4e03c4 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsABIInfo.cpp
@@ -15,6 +15,13 @@
 
 using namespace llvm;
 
+// Note: this option is defined here to be visible from libLLVMMipsAsmParser
+//       and libLLVMMipsCodeGen
+cl::opt<bool>
+EmitJalrReloc("mips-jalr-reloc", cl::Hidden,
+              cl::desc("MIPS: Emit R_{MICRO}MIPS_JALR relocation with jalr"),
+              cl::init(true));
+
 namespace {
 static const MCPhysReg O32IntRegs[4] = {Mips::A0, Mips::A1, Mips::A2, Mips::A3};
 
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsBaseInfo.h b/llvm/lib/Target/Mips/MCTargetDesc/MipsBaseInfo.h
index a90db2384c4..ab8a6753ead 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsBaseInfo.h
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsBaseInfo.h
@@ -89,7 +89,10 @@ namespace MipsII {
     MO_GOT_HI16,
     MO_GOT_LO16,
     MO_CALL_HI16,
-    MO_CALL_LO16
+    MO_CALL_LO16,
+
+    /// Helper operand used to generate R_MIPS_JALR
+    MO_JALR
   };
 
   enum {
diff --git a/llvm/lib/Target/Mips/MicroMips32r6InstrInfo.td b/llvm/lib/Target/Mips/MicroMips32r6InstrInfo.td
index 814918d25e7..c441aa76ad4 100644
--- a/llvm/lib/Target/Mips/MicroMips32r6InstrInfo.td
+++ b/llvm/lib/Target/Mips/MicroMips32r6InstrInfo.td
@@ -460,6 +460,7 @@ class JALRC16_MMR6_DESC_BASE<string opstr, RegisterOperand RO>
   let isCall = 1;
   let hasDelaySlot = 0;
   let Defs = [RA];
+  let hasPostISelHook = 1;
 }
 class JALRC16_MMR6_DESC : JALRC16_MMR6_DESC_BASE<"jalr", GPR32Opnd>;
 
diff --git a/llvm/lib/Target/Mips/MicroMipsInstrInfo.td b/llvm/lib/Target/Mips/MicroMipsInstrInfo.td
index af380a0ec71..ccc4f04bb92 100644
--- a/llvm/lib/Target/Mips/MicroMipsInstrInfo.td
+++ b/llvm/lib/Target/Mips/MicroMipsInstrInfo.td
@@ -426,6 +426,7 @@ class JumpLinkRegMM16<string opstr, RegisterOperand RO> :
   let isCall = 1;
   let hasDelaySlot = 1;
   let Defs = [RA];
+  let hasPostISelHook = 1;
 }
 
 // 16-bit Jump Reg
diff --git a/llvm/lib/Target/Mips/Mips32r6InstrInfo.td b/llvm/lib/Target/Mips/Mips32r6InstrInfo.td
index 2bd0cf2d59a..fb239f572ef 100644
--- a/llvm/lib/Target/Mips/Mips32r6InstrInfo.td
+++ b/llvm/lib/Target/Mips/Mips32r6InstrInfo.td
@@ -1105,7 +1105,7 @@ def : MipsPat<(select i32:$cond, immz, i32:$f),
 
 // Pseudo instructions
 let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1, hasDelaySlot = 1,
-    hasExtraSrcRegAllocReq = 1, isCTI = 1, Defs = [AT] in {
+    hasExtraSrcRegAllocReq = 1, isCTI = 1, Defs = [AT], hasPostISelHook = 1 in {
   class TailCallRegR6<Instruction JumpInst, Register RT, RegisterOperand RO> :
     PseudoSE<(outs), (ins RO:$rs), [(MipsTailCall RO:$rs)], II_JR>,
     PseudoInstExpansion<(JumpInst RT:$rt, RO:$rs)>;
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();
 
diff --git a/llvm/lib/Target/Mips/MipsFastISel.cpp b/llvm/lib/Target/Mips/MipsFastISel.cpp
index 22ade31a72c..a18416b9e86 100644
--- a/llvm/lib/Target/Mips/MipsFastISel.cpp
+++ b/llvm/lib/Target/Mips/MipsFastISel.cpp
@@ -56,6 +56,7 @@
 #include "llvm/IR/Type.h"
 #include "llvm/IR/User.h"
 #include "llvm/IR/Value.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCInstrDesc.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSymbol.h"
@@ -75,6 +76,8 @@
 
 using namespace llvm;
 
+extern cl::opt<bool> EmitJalrReloc;
+
 namespace {
 
 class MipsFastISel final : public FastISel {
@@ -1551,6 +1554,16 @@ bool MipsFastISel::fastLowerCall(CallLoweringInfo &CLI) {
 
   CLI.Call = MIB;
 
+  if (EmitJalrReloc && !Subtarget->inMips16Mode()) {
+    // Attach callee address to the instruction, let asm printer emit
+    // .reloc R_MIPS_JALR.
+    if (Symbol)
+      MIB.addSym(Symbol, MipsII::MO_JALR);
+    else
+      MIB.addSym(FuncInfo.MF->getContext().getOrCreateSymbol(
+	                   Addr.getGlobalValue()->getName()), MipsII::MO_JALR);
+  }
+
   // Finish off the call including any return values.
   return finishCall(CLI, RetVT, NumBytes);
 }
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.cpp b/llvm/lib/Target/Mips/MipsISelLowering.cpp
index 8c2a364cdfa..0f9c075ba0c 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.cpp
+++ b/llvm/lib/Target/Mips/MipsISelLowering.cpp
@@ -57,6 +57,7 @@
 #include "llvm/IR/GlobalValue.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/Value.h"
+#include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/Support/Casting.h"
 #include "llvm/Support/CodeGen.h"
@@ -91,6 +92,8 @@ NoZeroDivCheck("mno-check-zero-division", cl::Hidden,
                cl::desc("MIPS: Don't trap on integer division by zero."),
                cl::init(false));
 
+extern cl::opt<bool> EmitJalrReloc;
+
 static const MCPhysReg Mips64DPRegs[8] = {
   Mips::D12_64, Mips::D13_64, Mips::D14_64, Mips::D15_64,
   Mips::D16_64, Mips::D17_64, Mips::D18_64, Mips::D19_64
@@ -2879,6 +2882,54 @@ getOpndList(SmallVectorImpl<SDValue> &Ops,
     Ops.push_back(InFlag);
 }
 
+void MipsTargetLowering::AdjustInstrPostInstrSelection(MachineInstr &MI,
+                                                       SDNode *Node) const {
+  switch (MI.getOpcode()) {
+    default:
+      return;
+    case Mips::JALR:
+    case Mips::JALRPseudo:
+    case Mips::JALR64:
+    case Mips::JALR64Pseudo:
+    case Mips::JALR16_MM:
+    case Mips::JALRC16_MMR6:
+    case Mips::TAILCALLREG:
+    case Mips::TAILCALLREG64:
+    case Mips::TAILCALLR6REG:
+    case Mips::TAILCALL64R6REG:
+    case Mips::TAILCALLREG_MM:
+    case Mips::TAILCALLREG_MMR6: {
+      if (!EmitJalrReloc ||
+          Subtarget.inMips16Mode() ||
+          !isPositionIndependent() ||
+          Node->getNumOperands() < 1 ||
+          Node->getOperand(0).getNumOperands() < 2) {
+        return;
+      }
+      // We are after the callee address, set by LowerCall().
+      // If added to MI, asm printer will emit .reloc R_MIPS_JALR for the
+      // symbol.
+      const SDValue TargetAddr = Node->getOperand(0).getOperand(1);
+      StringRef Sym;
+      if (const GlobalAddressSDNode *G =
+              dyn_cast_or_null<const GlobalAddressSDNode>(TargetAddr)) {
+        Sym = G->getGlobal()->getName();
+      }
+      else if (const ExternalSymbolSDNode *ES =
+                   dyn_cast_or_null<const ExternalSymbolSDNode>(TargetAddr)) {
+        Sym = ES->getSymbol();
+      }
+
+      if (Sym.empty())
+        return;
+
+      MachineFunction *MF = MI.getParent()->getParent();
+      MCSymbol *S = MF->getContext().getOrCreateSymbol(Sym);
+      MI.addOperand(MachineOperand::CreateMCSymbol(S, MipsII::MO_JALR));
+    }
+  }
+}
+
 /// LowerCall - functions arguments are copied from virtual regs to
 /// (physical regs)/(stack frame), CALLSEQ_START and CALLSEQ_END are emitted.
 SDValue
@@ -2930,7 +2981,7 @@ MipsTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
   // the maximum out going argument area (including the reserved area), and
   // preallocates the stack space on entrance to the caller.
   //
-  // FIXME: We should do the same for efficency and space.
+  // FIXME: We should do the same for efficiency and space.
 
   // Note: The check on the calling convention below must match
   //       MipsABIInfo::GetCalleeAllocdArgSizeInBytes().
diff --git a/llvm/lib/Target/Mips/MipsISelLowering.h b/llvm/lib/Target/Mips/MipsISelLowering.h
index e043f133a09..c88633be02b 100644
--- a/llvm/lib/Target/Mips/MipsISelLowering.h
+++ b/llvm/lib/Target/Mips/MipsISelLowering.h
@@ -341,6 +341,9 @@ class TargetRegisterClass;
     EmitInstrWithCustomInserter(MachineInstr &MI,
                                 MachineBasicBlock *MBB) const override;
 
+    void AdjustInstrPostInstrSelection(MachineInstr &MI,
+                                       SDNode *Node) const override;
+
     void HandleByVal(CCState *, unsigned &, unsigned) const override;
 
     unsigned getRegisterByName(const char* RegName, EVT VT,
diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.cpp b/llvm/lib/Target/Mips/MipsInstrInfo.cpp
index bfb4c775205..e38bef4663a 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.cpp
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.cpp
@@ -653,6 +653,16 @@ MipsInstrInfo::genInstrWithNewOpc(unsigned NewOpc,
 
     MIB.addImm(0);
 
+    // If I has an MCSymbol operand (used by asm printer, to emit R_MIPS_JALR),
+    // add it to the new instruction.
+    for (unsigned J = I->getDesc().getNumOperands(), E = I->getNumOperands();
+         J < E; ++J) {
+      const MachineOperand &MO = I->getOperand(J);
+      if (MO.isMCSymbol() && (MO.getTargetFlags() & MipsII::MO_JALR))
+        MIB.addSym(MO.getMCSymbol(), MipsII::MO_JALR);
+    }
+
+
   } else {
     for (unsigned J = 0, E = I->getDesc().getNumOperands(); J < E; ++J) {
       if (BranchWithZeroOperand && (unsigned)ZeroOperandPosition == J)
@@ -825,7 +835,8 @@ MipsInstrInfo::getSerializableDirectMachineOperandTargetFlags() const {
     {MO_GOT_HI16,     "mips-got-hi16"},
     {MO_GOT_LO16,     "mips-got-lo16"},
     {MO_CALL_HI16,    "mips-call-hi16"},
-    {MO_CALL_LO16,    "mips-call-lo16"}
+    {MO_CALL_LO16,    "mips-call-lo16"},
+    {MO_JALR,         "mips-jalr"}
   };
   return makeArrayRef(Flags);
 }
diff --git a/llvm/lib/Target/Mips/MipsInstrInfo.td b/llvm/lib/Target/Mips/MipsInstrInfo.td
index d9398b7d602..46721e6cb9e 100644
--- a/llvm/lib/Target/Mips/MipsInstrInfo.td
+++ b/llvm/lib/Target/Mips/MipsInstrInfo.td
@@ -1623,11 +1623,15 @@ let isCall=1, hasDelaySlot=1, isCTI=1, Defs = [RA] in {
   class JumpLinkRegPseudo<RegisterOperand RO, Instruction JALRInst,
                           Register RetReg, RegisterOperand ResRO = RO>:
     PseudoSE<(outs), (ins RO:$rs), [(MipsJmpLink RO:$rs)], II_JALR>,
-    PseudoInstExpansion<(JALRInst RetReg, ResRO:$rs)>;
+    PseudoInstExpansion<(JALRInst RetReg, ResRO:$rs)> {
+    let hasPostISelHook = 1;
+  }
 
   class JumpLinkReg<string opstr, RegisterOperand RO>:
     InstSE<(outs RO:$rd), (ins RO:$rs), !strconcat(opstr, "\t$rd, $rs"),
-           [], II_JALR, FrmR, opstr>;
+           [], II_JALR, FrmR, opstr> {
+    let hasPostISelHook = 1;
+  }
 
   class BGEZAL_FT<string opstr, DAGOperand opnd,
                   RegisterOperand RO> :
@@ -1646,7 +1650,9 @@ let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1, hasDelaySlot = 1,
 
   class TailCallReg<Instruction JumpInst, RegisterOperand RO> :
     PseudoSE<(outs), (ins RO:$rs), [(MipsTailCall RO:$rs)], II_JR>,
-    PseudoInstExpansion<(JumpInst RO:$rs)>;
+    PseudoInstExpansion<(JumpInst RO:$rs)> {
+    let hasPostISelHook = 1;
+  }
 }
 
 class BAL_BR_Pseudo<Instruction RealInst, DAGOperand opnd> :
diff --git a/llvm/lib/Target/Mips/MipsMCInstLower.cpp b/llvm/lib/Target/Mips/MipsMCInstLower.cpp
index 46b37ceae39..4a7c0ce2be1 100644
--- a/llvm/lib/Target/Mips/MipsMCInstLower.cpp
+++ b/llvm/lib/Target/Mips/MipsMCInstLower.cpp
@@ -117,6 +117,8 @@ MCOperand MipsMCInstLower::LowerSymbolOperand(const MachineOperand &MO,
   case MipsII::MO_CALL_LO16:
     TargetKind = MipsMCExpr::MEK_CALL_LO16;
     break;
+  case MipsII::MO_JALR:
+    return MCOperand();
   }
 
   switch (MOTy) {