[mips][microMIPSr6] Implement BALC and BC instructions

[jkolek]

Summary

This patch implements BALC and BC instructions using mapping.

[dsanders]

Could you add a disassembler test too?

LGTM with the disassembler test.

[jkolek]

Initial microMIPSr6 disassembler support is in separate patch, and it requires auto generated DecoderTableMicroMips32r632, which is not generated until some of the instructions exists. These instruction are the first microMIPSr6 instructions implemented, so after this patch the patch for microMIPSr6 disassembler support (http://reviews.llvm.org/D8490) will be committed and therefore the BALC and BC disassembler tests with it.

[dsanders]

In D8388#158251, @jkolek wrote:

Initial microMIPSr6 disassembler support is in separate patch, and it requires auto generated DecoderTableMicroMips32r632, which is not generated until some of the instructions exists. These instruction are the first microMIPSr6 instructions implemented, so after this patch the patch for microMIPSr6 disassembler support (http://reviews.llvm.org/D8490) will be committed and therefore the BALC and BC disassembler tests with it.

That sounds good to me. Thanks

lib/Target/Mips/MicroMips32r6InstrInfo.td

+//=- MicroMips32r6InstrInfo.td - MicroMips r6 Instruction Information -*- tablegen -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file describes microMIPSr6 instructions.
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+//
+// Instruction Encodings
+//
+//===----------------------------------------------------------------------===//
+
+class BALC_MMR6_ENC  : BRANCH_OFF26_FM<0b101101>;
+class BC_MMR6_ENC : BRANCH_OFF26_FM<0b100101>;
+
+//===----------------------------------------------------------------------===//
+//
+// Instruction Descriptions
+//
+//===----------------------------------------------------------------------===//
+
+class BC_MMR6_DESC_BASE<string instr_asm, DAGOperand opnd>
+    : BRANCH_DESC_BASE, MMR6Arch<instr_asm> {
+  dag InOperandList = (ins opnd:$offset);
+  dag OutOperandList = (outs);
+  string AsmString = !strconcat(instr_asm, "\t$offset");
+  bit isBarrier = 1;
+}
+
+class BALC_MMR6_DESC : BC_MMR6_DESC_BASE<"balc", brtarget26> {
+  bit isCall = 1;
+  list<Register> Defs = [RA];
+}
+class BC_MMR6_DESC : BC_MMR6_DESC_BASE<"bc", brtarget26>;
+
+//===----------------------------------------------------------------------===//
+//
+// Instruction Definitions
+//
+//===----------------------------------------------------------------------===//
+
+def BALC_MMR6 : R6MMR6Rel, BALC_MMR6_ENC, BALC_MMR6_DESC, ISA_MICROMIPS32R6;
+def BC_MMR6 : R6MMR6Rel, BC_MMR6_ENC, BC_MMR6_DESC, ISA_MICROMIPS32R6;

lib/Target/Mips/Mips32r6InstrInfo.td

 class AUI_DESC : AUI_DESC_BASE<"aui", GPR32Opnd>;
 
 class BRANCH_DESC_BASE {
   bit isBranch = 1;
   bit isTerminator = 1;
   bit hasDelaySlot = 0;
 }
 
-class BC_DESC_BASE<string instr_asm, DAGOperand opnd> : BRANCH_DESC_BASE {
+class BC_DESC_BASE<string instr_asm, DAGOperand opnd> : BRANCH_DESC_BASE,
+    MipsR6Arch<instr_asm> {
   dag InOperandList = (ins opnd:$offset);
   dag OutOperandList = (outs);
   string AsmString = !strconcat(instr_asm, "\t$offset");
   bit isBarrier = 1;
 }
 
 class CMP_BC_DESC_BASE<string instr_asm, DAGOperand opnd,
                        RegisterOperand GPROpnd> : BRANCH_DESC_BASE {

 //===----------------------------------------------------------------------===//
 
 def ADDIUPC : ADDIUPC_ENC, ADDIUPC_DESC, ISA_MIPS32R6;
 def ALIGN : ALIGN_ENC, ALIGN_DESC, ISA_MIPS32R6;
 def ALUIPC : ALUIPC_ENC, ALUIPC_DESC, ISA_MIPS32R6;
 def AUI : AUI_ENC, AUI_DESC, ISA_MIPS32R6;
 def AUIPC : AUIPC_ENC, AUIPC_DESC, ISA_MIPS32R6;
 def BAL : BAL_ENC, BAL_DESC, ISA_MIPS32R6;
-def BALC : BALC_ENC, BALC_DESC, ISA_MIPS32R6;
+def BALC : R6MMR6Rel, BALC_ENC, BALC_DESC, ISA_MIPS32R6;
 def BC1EQZ : BC1EQZ_ENC, BC1EQZ_DESC, ISA_MIPS32R6;
 def BC1NEZ : BC1NEZ_ENC, BC1NEZ_DESC, ISA_MIPS32R6;
 def BC2EQZ : BC2EQZ_ENC, BC2EQZ_DESC, ISA_MIPS32R6;
 def BC2NEZ : BC2NEZ_ENC, BC2NEZ_DESC, ISA_MIPS32R6;
-def BC : BC_ENC, BC_DESC, ISA_MIPS32R6;
+def BC : R6MMR6Rel, BC_ENC, BC_DESC, ISA_MIPS32R6;
 def BEQC : BEQC_ENC, BEQC_DESC, ISA_MIPS32R6;
 def BEQZALC : BEQZALC_ENC, BEQZALC_DESC, ISA_MIPS32R6;
 def BEQZC : BEQZC_ENC, BEQZC_DESC, ISA_MIPS32R6;
 def BGEC : BGEC_ENC, BGEC_DESC, ISA_MIPS32R6;
 def BGEUC : BGEUC_ENC, BGEUC_DESC, ISA_MIPS32R6;
 def BGEZALC : BGEZALC_ENC, BGEZALC_DESC, ISA_MIPS32R6;
 def BGEZC : BGEZC_ENC, BGEZC_DESC, ISA_MIPS32R6;
 def BGTZALC : BGTZALC_ENC, BGTZALC_DESC, ISA_MIPS32R6;

lib/Target/Mips/MipsInstrInfo.td

 // MSA
 include "MipsMSAInstrFormats.td"
 include "MipsMSAInstrInfo.td"
 
 // Micromips
 include "MicroMipsInstrFormats.td"
 include "MicroMipsInstrInfo.td"
 include "MicroMipsInstrFPU.td"
+
+// Micromips r6
+include "MicroMips32r6InstrFormats.td"
+include "MicroMips32r6InstrInfo.td"

test/MC/Mips/micromips32r6/valid.s

+# RUN: llvm-mc %s -triple=mips-unknown-linux -show-encoding -mcpu=mips32r6 -mattr=micromips | FileCheck %s
+
+  .set noat
+  balc 14572256            # CHECK: balc 14572256       # encoding: [0xb4,0x37,0x96,0xb8]
+  bc 14572256              # CHECK: bc 14572256         # encoding: [0x94,0x37,0x96,0xb8]