Thumb conditional branch binary encodings. rdar://8745367

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121493 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/ARM/ARMAsmBackend.cpp

@@ -200,6 +200,9 @@ static unsigned adjustFixupValue(unsigned Kind, uint64_t Value) {
     uint32_t Binary = (Value - 4) >> 1;
     return ((Binary & 0x20) << 9) | ((Binary & 0x1f) << 3);
   }
+  case ARM::fixup_arm_thumb_bcc:
+    // Offset by 4 and don't encode the lower bit, which is always 0.
+    return ((Value - 4) >> 1) & 0xff;
   case ARM::fixup_arm_pcrel_10:
     Value = Value - 6; // ARM fixups offset by an additional word and don't
                        // need to adjust for the half-word ordering.
@@ -310,6 +313,7 @@ static unsigned getFixupKindNumBytes(unsigned Kind) {
   default:
     llvm_unreachable("Unknown fixup kind!");
 
+  case ARM::fixup_arm_thumb_bcc:
   case ARM::fixup_arm_thumb_cp:
     return 1;
 

lib/Target/ARM/ARMCodeEmitter.cpp

@@ -175,6 +175,8 @@ namespace {
       const { return 0; }
     unsigned getThumbBLXTargetOpValue(const MachineInstr &MI, unsigned Op)
       const { return 0; }
+    unsigned getThumbBCCTargetOpValue(const MachineInstr &MI, unsigned Op)
+      const { return 0; }
     unsigned getThumbCBTargetOpValue(const MachineInstr &MI, unsigned Op)
       const { return 0; }
     unsigned getBranchTargetOpValue(const MachineInstr &MI, unsigned Op)

lib/Target/ARM/ARMFixupKinds.h

@@ -52,6 +52,9 @@ enum Fixups {
   // fixup_arm_thumb_cp - Fixup for Thumb load/store from constant pool instrs.
   fixup_arm_thumb_cp,
 
+  // fixup_arm_thumb_bcc - Fixup for Thumb load/store from constant pool instrs.
+  fixup_arm_thumb_bcc,
+
   // The next two are for the movt/movw pair
   // the 16bit imm field are split into imm{15-12} and imm{11-0}
   // Fixme: We need new ones for Thumb.

lib/Target/ARM/ARMInstrThumb.td

@@ -74,6 +74,10 @@ def t_imm_s4 : Operand<i32> {
 
 // Define Thumb specific addressing modes.
 
+def t_bcctarget : Operand<i32> {
+  let EncoderMethod = "getThumbBCCTargetOpValue";
+}
+
 def t_cbtarget : Operand<i32> {
   let EncoderMethod = "getThumbCBTargetOpValue";
 }
@@ -508,12 +512,14 @@ let isBranch = 1, isTerminator = 1, isBarrier = 1 in {
 // FIXME: should be able to write a pattern for ARMBrcond, but can't use
 // a two-value operand where a dag node expects two operands. :(
 let isBranch = 1, isTerminator = 1 in
-  def tBcc : T1I<(outs), (ins brtarget:$target, pred:$p), IIC_Br,
+  def tBcc : T1I<(outs), (ins t_bcctarget:$target, pred:$p), IIC_Br,
                  "b${p}\t$target",
                  [/*(ARMbrcond bb:$target, imm:$cc)*/]>,
              T1Encoding<{1,1,0,1,?,?}> {
   bits<4> p;
+  bits<8> target;
   let Inst{11-8} = p;
+  let Inst{7-0} = target;
 }
 
 // Compare and branch on zero / non-zero

lib/Target/ARM/ARMMCCodeEmitter.cpp

@@ -59,6 +59,7 @@ public:
       { "fixup_arm_thumb_blx",      0,    32,   MCFixupKindInfo::FKF_IsPCRel },
       { "fixup_arm_thumb_cb",       0,    16,   MCFixupKindInfo::FKF_IsPCRel },
       { "fixup_arm_thumb_cp",       1,    8,    MCFixupKindInfo::FKF_IsPCRel },
+      { "fixup_arm_thumb_bcc",      1,    8,    MCFixupKindInfo::FKF_IsPCRel },
       { "fixup_arm_movt_hi16",      0,    16,   0 },
       { "fixup_arm_movw_lo16",      0,    16,   0 },
     };
@@ -100,6 +101,10 @@ public:
   uint32_t getThumbBLXTargetOpValue(const MCInst &MI, unsigned OpIdx,
                                     SmallVectorImpl<MCFixup> &Fixups) const;
 
+  /// getThumbBCCTargetOpValue - Return encoding info for Thumb branch target.
+  uint32_t getThumbBCCTargetOpValue(const MCInst &MI, unsigned OpIdx,
+                                    SmallVectorImpl<MCFixup> &Fixups) const;
+
   /// getThumbCBTargetOpValue - Return encoding info for Thumb branch target.
   uint32_t getThumbCBTargetOpValue(const MCInst &MI, unsigned OpIdx,
                                    SmallVectorImpl<MCFixup> &Fixups) const;
@@ -452,6 +457,13 @@ getThumbBLXTargetOpValue(const MCInst &MI, unsigned OpIdx,
   return ::getBranchTargetOpValue(MI, OpIdx, ARM::fixup_arm_thumb_blx, Fixups);
 }
 
+/// getThumbBCCTargetOpValue - Return encoding info for Thumb branch target.
+uint32_t ARMMCCodeEmitter::
+getThumbBCCTargetOpValue(const MCInst &MI, unsigned OpIdx,
+                        SmallVectorImpl<MCFixup> &Fixups) const {
+  return ::getBranchTargetOpValue(MI, OpIdx, ARM::fixup_arm_thumb_bcc, Fixups);
+}
+
 /// getThumbCBTargetOpValue - Return encoding info for Thumb branch target.
 uint32_t ARMMCCodeEmitter::
 getThumbCBTargetOpValue(const MCInst &MI, unsigned OpIdx,

utils/TableGen/EDEmitter.cpp

@@ -587,6 +587,7 @@ static int ARMFlagFromOpName(LiteralConstantEmitter *type,
   IMM("neon_vcvt_imm32");
 
   MISC("brtarget", "kOperandTypeARMBranchTarget");                // ?
+  MISC("t_bcctarget", "kOperandTypeARMBranchTarget");             // ?
   MISC("t_cbtarget", "kOperandTypeARMBranchTarget");              // ?
   MISC("bltarget", "kOperandTypeARMBranchTarget");                // ?
   MISC("t_bltarget", "kOperandTypeARMBranchTarget");              // ?