[PATCH][mips] Add range checks and transformation to octeon instructions in AsmParser.

[Kai]

Summary

Hi Daniel!

This patch adds range checks to the immediate operands of octeon
instructions in the AsmParser. Like gas, it applies the following
transformations if the immediate is to large:

bbit0 $8, 42, foo => bbit032 $8, 10, foo
bbit1 $8, 46, foo => bbit132 $8, 14, foo
cins $8, $31, 32, 31 => cins32 $8, $31, 0, 31
exts $7, $4, 54, 9 => exts32 $7, $4, 22, 9

Please review.

Regards,
Kai

[dsanders]

LGTM with a couple nits.

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

1177

Please add a comment to show that the fall through is deliberate.

1254

C++ style comments are preferred. Likewise for the others below.

1264

Indentation. The ':' should line up with the '?'.

[Kai]

Thanks. Committed as r227225.

Regards,
Kai

lib/Target/Mips/AsmParser/MipsAsmParser.cpp

bool hasMips64r2() const {
     return (STI.getFeatureBits() & Mips::FeatureMips64r2);
   }
   bool hasMips32r6() const {
     return (STI.getFeatureBits() & Mips::FeatureMips32r6);
   }
   bool hasMips64r6() const {
     return (STI.getFeatureBits() & Mips::FeatureMips64r6);
   }
+  bool hasCnMips() const {
+    return (STI.getFeatureBits() & Mips::FeatureCnMips);
+  }
   bool hasDSP() const { return (STI.getFeatureBits() & Mips::FeatureDSP); }
   bool hasDSPR2() const { return (STI.getFeatureBits() & Mips::FeatureDSPR2); }
   bool hasMSA() const { return (STI.getFeatureBits() & Mips::FeatureMSA); }
 
   bool inMips16Mode() const {
     return STI.getFeatureBits() & Mips::FeatureMips16;
   }
   // TODO: see how can we get this info.
bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
 
   if (MCID.isBranch() || MCID.isCall()) {
     const unsigned Opcode = Inst.getOpcode();
     MCOperand Offset;
 
     switch (Opcode) {
     default:
       break;
+    case Mips::BBIT0:
+    case Mips::BBIT032:
+    case Mips::BBIT1:
+    case Mips::BBIT132:
+      assert(hasCnMips() && "instruction only valid for octeon cpus");
     case Mips::BEQ:
     case Mips::BNE:
     case Mips::BEQ_MM:
     case Mips::BNE_MM:
       assert(MCID.getNumOperands() == 3 && "unexpected number of operands");
       Offset = Inst.getOperand(2);
       if (!Offset.isImm())
         break; // We'll deal with this situation later on when applying fixups.
bool MipsAsmParser::processInstruction(MCInst &Inst, SMLoc IDLoc,
   // SSNOP is deprecated on MIPS32r6/MIPS64r6
   // We still accept it but it is a normal nop.
   if (hasMips32r6() && Inst.getOpcode() == Mips::SSNOP) {
     std::string ISA = hasMips64r6() ? "MIPS64r6" : "MIPS32r6";
     Warning(IDLoc, "ssnop is deprecated for " + ISA + " and is equivalent to a "
                                                       "nop instruction");
   }
 
+  if (hasCnMips()) {
+    const unsigned Opcode = Inst.getOpcode();
+    MCOperand Opnd;
+    int Imm;
+
+    switch (Opcode) {
+      default:
+        break;
+
+      case Mips::BBIT0:
+      case Mips::BBIT032:
+      case Mips::BBIT1:
+      case Mips::BBIT132:
+        assert(MCID.getNumOperands() == 3 && "unexpected number of operands");
+        /* The offset is handled above */
+        Opnd = Inst.getOperand(1);
+        if (!Opnd.isImm())
+          return Error(IDLoc, "expected immediate operand kind");
+        Imm = Opnd.getImm();
+        if (Imm < 0 || Imm > (Opcode == Mips::BBIT0 ||
+                              Opcode == Mips::BBIT1 ? 63 : 31))
+          return Error(IDLoc, "immediate operand value out of range");
+        if (Imm > 31) {
+          Inst.setOpcode(Opcode == Mips::BBIT0 ? Mips::BBIT032
+            : Mips::BBIT132);
+          Inst.getOperand(1).setImm(Imm - 32);
+        }
+        break;
+
+      case Mips::CINS:
+      case Mips::CINS32:
+      case Mips::EXTS:
+      case Mips::EXTS32:
+        assert(MCID.getNumOperands() == 4 && "unexpected number of operands");
+        /* Check length */
+        Opnd = Inst.getOperand(3);
+        if (!Opnd.isImm())
+          return Error(IDLoc, "expected immediate operand kind");
+        Imm = Opnd.getImm();
+        if (Imm < 0 || Imm > 31)
+          return Error(IDLoc, "immediate operand value out of range");
+        /* Check position */
+        Opnd = Inst.getOperand(2);
+        if (!Opnd.isImm())
+          return Error(IDLoc, "expected immediate operand kind");
+        Imm = Opnd.getImm();
+        if (Imm < 0 || Imm > (Opcode == Mips::CINS ||
+                              Opcode == Mips::EXTS ? 63 : 31))
+          return Error(IDLoc, "immediate operand value out of range");
+        if (Imm > 31) {
+          Inst.setOpcode(Opcode == Mips::CINS ? Mips::CINS32 : Mips::EXTS32);
+          Inst.getOperand(2).setImm(Imm - 32);
+        }
+        break;
+
+      case Mips::SEQi:
+      case Mips::SNEi:
+        assert(MCID.getNumOperands() == 3 && "unexpected number of operands");
+        Opnd = Inst.getOperand(2);
+        if (!Opnd.isImm())
+          return Error(IDLoc, "expected immediate operand kind");
+        Imm = Opnd.getImm();
+        if (!isInt<10>(Imm))
+          return Error(IDLoc, "immediate operand value out of range");
+        break;
+    }
+  }
+
   if (MCID.hasDelaySlot() && AssemblerOptions.back()->isReorder()) {
     // If this instruction has a delay slot and .set reorder is active,
     // emit a NOP after it.
     Instructions.push_back(Inst);
     MCInst NopInst;
     if (hasShortDelaySlot(Inst.getOpcode())) {
       NopInst.setOpcode(Mips::MOVE16_MM);
       NopInst.addOperand(MCOperand::CreateReg(Mips::ZERO));

test/MC/Mips/octeon-instructions.s

 # RUN: llvm-mc  %s -triple=mips64-unknown-linux -show-encoding -mcpu=octeon | FileCheck %s
 
 # CHECK: baddu $9, $6, $7             # encoding: [0x70,0xc7,0x48,0x28]
 # CHECK: baddu $17, $18, $19          # encoding: [0x72,0x53,0x88,0x28]
 # CHECK: baddu $2, $2, $3             # encoding: [0x70,0x43,0x10,0x28]
 # CHECK: bbit0 $19, 22, foo           # encoding: [0xca,0x76,A,A]
 # CHECK: bbit032 $fp, 11, foo         # encoding: [0xdb,0xcb,A,A]
+# CHECK: bbit032 $8, 10, foo          # encoding: [0xd9,0x0a,A,A]
 # CHECK: bbit1 $3, 31, foo            # encoding: [0xe8,0x7f,A,A]
 # CHECK: bbit132 $24, 10, foo         # encoding: [0xfb,0x0a,A,A]
+# CHECK: bbit132 $14, 14, foo         # encoding: [0xf9,0xce,A,A]
 # CHECK: cins  $25, $10, 22, 2        # encoding: [0x71,0x59,0x15,0xb2]
 # CHECK: cins  $9, $9, 17, 29         # encoding: [0x71,0x29,0xec,0x72]
 # CHECK: cins32 $15, $2, 18, 8        # encoding: [0x70,0x4f,0x44,0xb3]
 # CHECK: cins32 $22, $22, 9, 22       # encoding: [0x72,0xd6,0xb2,0x73]
+# CHECK: cins32 $24, $ra, 0, 31       # encoding: [0x73,0xf8,0xf8,0x33]
+# CHECK: cins32 $15, $15, 5, 5        # encoding: [0x71,0xef,0x29,0x73]
 # CHECK: dmul  $9, $6, $7             # encoding: [0x70,0xc7,0x48,0x03]
 # CHECK: dmul  $19, $24, $25          # encoding: [0x73,0x19,0x98,0x03]
 # CHECK: dmul  $9, $9, $6             # encoding: [0x71,0x26,0x48,0x03]
 # CHECK: dmul  $21, $21, $25          # encoding: [0x72,0xb9,0xa8,0x03]
 # CHECK: dpop  $9, $6                 # encoding: [0x70,0xc0,0x48,0x2d]
 # CHECK: dpop  $15, $22               # encoding: [0x72,0xc0,0x78,0x2d]
 # CHECK: dpop  $12, $12               # encoding: [0x71,0x80,0x60,0x2d]
 # CHECK: exts  $4, $25, 27, 15        # encoding: [0x73,0x24,0x7e,0xfa]
 # CHECK: exts  $15, $15, 17, 6        # encoding: [0x71,0xef,0x34,0x7a]
 # CHECK: exts32 $4, $13, 10, 8        # encoding: [0x71,0xa4,0x42,0xbb]
 # CHECK: exts32 $15, $15, 11, 20      # encoding: [0x71,0xef,0xa2,0xfb]
+# CHECK: exts32 $7, $4, 22, 9         # encoding: [0x70,0x87,0x4d,0xbb]
+# CHECK: exts32 $25, $25, 5, 25       # encoding: [0x73,0x39,0xc9,0x7b]
 # CHECK: mtm0  $15                    # encoding: [0x71,0xe0,0x00,0x08]
 # CHECK: mtm1  $16                    # encoding: [0x72,0x00,0x00,0x0c]
 # CHECK: mtm2  $17                    # encoding: [0x72,0x20,0x00,0x0d]
 # CHECK: mtp0  $18                    # encoding: [0x72,0x40,0x00,0x09]
 # CHECK: mtp1  $19                    # encoding: [0x72,0x60,0x00,0x0a]
 # CHECK: mtp2  $20                    # encoding: [0x72,0x80,0x00,0x0b]
 # CHECK: pop   $9, $6                 # encoding: [0x70,0xc0,0x48,0x2c]
 # CHECK: pop   $8, $19                # encoding: [0x72,0x60,0x40,0x2c]

 # CHECK: vmulu $27, $27, $6           # encoding: [0x73,0x66,0xd8,0x0f]
 
 foo:
   baddu $9, $6, $7
   baddu $17, $18, $19
   baddu $2, $3
   bbit0 $19, 22, foo
   bbit032 $30, 11, foo
+  bbit0 $8, 42, foo
   bbit1 $3, 31, foo
   bbit132 $24, 10, foo
+  bbit1 $14, 46, foo
   cins  $25, $10, 22, 2
   cins  $9, 17, 29
   cins32 $15, $2, 18, 8
   cins32 $22, 9, 22
+  cins  $24, $31, 32, 31
+  cins  $15, 37, 5
   dmul  $9, $6, $7
   dmul  $19, $24, $25
   dmul  $9, $6
   dmul  $21, $25
   dpop  $9, $6
   dpop  $15, $22
   dpop  $12
   exts  $4, $25, 27, 15
   exts  $15, 17, 6
   exts32 $4, $13, 10, 8
   exts32 $15, 11, 20
+  exts  $7, $4, 54, 9
+  exts  $25, 37, 25
   mtm0  $15
   mtm1  $16
   mtm2  $17
   mtp0  $18
   mtp1  $19
   mtp2  $20
   pop   $9, $6
   pop   $8, $19