[Sparc] Add return/rett instruction to Sparc backend.

llvm-svn: 202666

llvm/lib/Target/Sparc/AsmParser/SparcAsmParser.cpp

@@ -446,6 +446,9 @@ ParseRegister(unsigned &RegNo, SMLoc &StartLoc, SMLoc &EndLoc)
   return Error(StartLoc, "invalid register name");
 }
 
+static void applyMnemonicAliases(StringRef &Mnemonic, unsigned Features,
+                                 unsigned VariantID);
+
 bool SparcAsmParser::
 ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
                  SMLoc NameLoc,
@@ -455,6 +458,9 @@ ParseInstruction(ParseInstructionInfo &Info, StringRef Name,
   // First operand in MCInst is instruction mnemonic.
   Operands.push_back(SparcOperand::CreateToken(Name, NameLoc));
 
+  // apply mnemonic aliases, if any, so that we can parse operands correctly.
+  applyMnemonicAliases(Name, getAvailableFeatures(), 0);
+
   if (getLexer().isNot(AsmToken::EndOfStatement)) {
     // Read the first operand.
     if (getLexer().is(AsmToken::Comma)) {

llvm/lib/Target/Sparc/Disassembler/SparcDisassembler.cpp

@@ -209,6 +209,8 @@ static DecodeStatus DecodeSIMM13(MCInst &Inst, unsigned insn,
                                  uint64_t Address, const void *Decoder);
 static DecodeStatus DecodeJMPL(MCInst &Inst, unsigned insn, uint64_t Address,
                                const void *Decoder);
+static DecodeStatus DecodeReturn(MCInst &MI, unsigned insn, uint64_t Address,
+                                 const void *Decoder);
 
 #include "SparcGenDisassemblerTables.inc"
 
@@ -415,3 +417,31 @@ static DecodeStatus DecodeJMPL(MCInst &MI, unsigned insn, uint64_t Address,
   }
   return MCDisassembler::Success;
 }
+
+static DecodeStatus DecodeReturn(MCInst &MI, unsigned insn, uint64_t Address,
+                                 const void *Decoder) {
+
+  unsigned rs1 = fieldFromInstruction(insn, 14, 5);
+  unsigned isImm = fieldFromInstruction(insn, 13, 1);
+  unsigned rs2 = 0;
+  unsigned simm13 = 0;
+  if (isImm)
+    simm13 = SignExtend32<13>(fieldFromInstruction(insn, 0, 13));
+  else
+    rs2 = fieldFromInstruction(insn, 0, 5);
+
+  // Decode RS1.
+  DecodeStatus status = DecodeIntRegsRegisterClass(MI, rs1, Address, Decoder);
+  if (status != MCDisassembler::Success)
+    return status;
+
+  // Decode RS2 | SIMM13.
+  if (isImm)
+    MI.addOperand(MCOperand::CreateImm(simm13));
+  else {
+    status = DecodeIntRegsRegisterClass(MI, rs2, Address, Decoder);
+    if (status != MCDisassembler::Success)
+      return status;
+  }
+  return MCDisassembler::Success;
+}

llvm/lib/Target/Sparc/SparcInstrAliases.td

@@ -249,6 +249,8 @@ def : InstAlias<"mov $simm13, $rd", (ORri IntRegs:$rd, G0, i32imm:$simm13)>;
 // restore -> restore %g0, %g0, %g0
 def : InstAlias<"restore", (RESTORErr G0, G0, G0)>;
 
+def : MnemonicAlias<"return", "rett">, Requires<[HasV9]>;
+
 def : MnemonicAlias<"addc", "addx">, Requires<[HasV9]>;
 def : MnemonicAlias<"addccc", "addxcc">, Requires<[HasV9]>;
 

llvm/lib/Target/Sparc/SparcInstrInfo.td

@@ -406,6 +406,14 @@ let isReturn = 1, isTerminator = 1, hasDelaySlot = 1, isBarrier = 1,
                   "jmp %i7+$val", []>;
 }
 
+let isReturn = 1, isTerminator = 1, hasDelaySlot = 1,
+     isBarrier = 1, rd = 0, DecoderMethod = "DecodeReturn" in {
+  def RETTrr : F3_1<2, 0b111001, (outs), (ins MEMrr:$addr),
+                       "rett $addr", []>;
+  def RETTri : F3_2<2, 0b111001, (outs), (ins MEMri:$addr),
+                       "rett $addr", []>;
+}
+
 // Section B.1 - Load Integer Instructions, p. 90
 let DecoderMethod = "DecodeLoadInt" in {
   defm LDSB : Load<"ldsb", 0b001001, sextloadi8,  IntRegs, i32>;

llvm/test/MC/Disassembler/Sparc/sparc.txt

@@ -197,3 +197,6 @@
 
 # CHECK: ret
 0x81,0xc7,0xe0,0x08
+
+# CHECK:  rett %i7+8
+0x81 0xcf 0xe0 0x08

llvm/test/MC/Sparc/sparc-ctrl-instructions.s

@@ -274,3 +274,5 @@
         ! CHECK-NEXT:                                        !   fixup A - offset: 0, value: .BB0, kind: fixup_sparc_br22
         fbo,a .BB0
 
+        ! CHECK:  rett %i7+8   ! encoding: [0x81,0xcf,0xe0,0x08]
+        rett %i7 + 8

llvm/test/MC/Sparc/sparc64-ctrl-instructions.s

@@ -1214,3 +1214,6 @@
         fmovrsnz  %g1, %f2, %f3
         fmovrsgz  %g1, %f2, %f3
         fmovrsgez %g1, %f2, %f3
+
+        ! CHECK:  rett %i7+8   ! encoding: [0x81,0xcf,0xe0,0x08]
+        return %i7 + 8