Improve encoding support for BLX with immediat eoperands, and fix a BLX decoding bug this uncovered.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138675 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 25 insertions, 12 deletions

diff --git a/lib/Target/ARM/ARMCodeEmitter.cpp b/lib/Target/ARM/ARMCodeEmitter.cpp
index 7d4eb6f18f..8f28c43173 100644
--- a/lib/Target/ARM/ARMCodeEmitter.cpp
+++ b/lib/Target/ARM/ARMCodeEmitter.cpp
@@ -189,6 +189,8 @@ namespace {
       unsigned Op) const { return 0; }
     unsigned getARMBranchTargetOpValue(const MachineInstr &MI, unsigned Op)
       const { return 0; }
+    unsigned getARMBLXTargetOpValue(const MachineInstr &MI, unsigned Op)
+      const { return 0; }
     unsigned getCCOutOpValue(const MachineInstr &MI, unsigned Op)
       const { return 0; }
     unsigned getSOImmOpValue(const MachineInstr &MI, unsigned Op)
diff --git a/lib/Target/ARM/ARMInstrInfo.td b/lib/Target/ARM/ARMInstrInfo.td
index d20e944ddf..56a4d831e1 100644
--- a/lib/Target/ARM/ARMInstrInfo.td
+++ b/lib/Target/ARM/ARMInstrInfo.td
@@ -344,9 +344,13 @@ def bl_target : Operand<i32> {
   // Encoded the same as branch targets.
   let EncoderMethod = "getARMBranchTargetOpValue";
   let OperandType = "OPERAND_PCREL";
-  let DecoderMethod = "DecodeBLTargetOperand";
 }
 
+def blx_target : Operand<i32> {
+  // Encoded the same as branch targets.
+  let EncoderMethod = "getARMBLXTargetOpValue";
+  let OperandType = "OPERAND_PCREL";
+}
 
 // A list of registers separated by comma. Used by load/store multiple.
 def RegListAsmOperand : AsmOperandClass { let Name = "RegList"; }
@@ -1657,6 +1661,7 @@ let isCall = 1,
     let Inst{31-28} = 0b1110;
     bits<24> func;
     let Inst{23-0} = func;
+    let DecoderMethod = "DecodeBranchImmInstruction";
   }
 
   def BL_pred : ABI<0b1011, (outs), (ins bl_target:$func, variable_ops),
@@ -1665,6 +1670,7 @@ let isCall = 1,
                 Requires<[IsARM, IsNotDarwin]> {
     bits<24> func;
     let Inst{23-0} = func;
+    let DecoderMethod = "DecodeBranchImmInstruction";
   }
 
   // ARMv5T and above
@@ -1784,7 +1790,7 @@ let isBranch = 1, isTerminator = 1 in {
 }
 
 // BLX (immediate)
-def BLXi : AXI<(outs), (ins br_target:$target), BrMiscFrm, NoItinerary,
+def BLXi : AXI<(outs), (ins blx_target:$target), BrMiscFrm, NoItinerary,
                "blx\t$target", []>,
            Requires<[IsARM, HasV5T]> {
   let Inst{31-25} = 0b1111101;
diff --git a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
index 6b87dfd0df..c3ad2907c9 100644
--- a/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
+++ b/lib/Target/ARM/Disassembler/ARMDisassembler.cpp
@@ -69,8 +69,6 @@ static DecodeStatus DecodeCCOutOperand(llvm::MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder);
 static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder);
-static DecodeStatus DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
-                               uint64_t Address, const void *Decoder);
 static DecodeStatus DecodeRegListOperand(llvm::MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder);
 static DecodeStatus DecodeSPRRegListOperand(llvm::MCInst &Inst, unsigned Val,
@@ -766,13 +764,6 @@ static DecodeStatus DecodeSOImmOperand(llvm::MCInst &Inst, unsigned Val,
   return Success;
 }
 
-static DecodeStatus DecodeBLTargetOperand(llvm::MCInst &Inst, unsigned Val,
-                               uint64_t Address, const void *Decoder) {
-  Val <<= 2;
-  Inst.addOperand(MCOperand::CreateImm(SignExtend32<26>(Val)));
-  return Success;
-}
-
 static DecodeStatus DecodeSORegImmOperand(llvm::MCInst &Inst, unsigned Val,
                                uint64_t Address, const void *Decoder) {
   DecodeStatus S = Success;
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
index 19a37356b2..94aeb59089 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
@@ -118,6 +118,8 @@ public:
   /// branch target.
   uint32_t getARMBranchTargetOpValue(const MCInst &MI, unsigned OpIdx,
                                      SmallVectorImpl<MCFixup> &Fixups) const;
+  uint32_t getARMBLXTargetOpValue(const MCInst &MI, unsigned OpIdx,
+                                     SmallVectorImpl<MCFixup> &Fixups) const;
 
   /// getAdrLabelOpValue - Return encoding info for 12-bit immediate
   /// ADR label target.
@@ -544,8 +546,20 @@ getARMBranchTargetOpValue(const MCInst &MI, unsigned OpIdx,
   return MO.getImm() >> 2;
 }
 
+uint32_t ARMMCCodeEmitter::
+getARMBLXTargetOpValue(const MCInst &MI, unsigned OpIdx,
+                          SmallVectorImpl<MCFixup> &Fixups) const {
+  const MCOperand MO = MI.getOperand(OpIdx);
+  if (MO.isExpr()) {
+    if (HasConditionalBranch(MI)) 
+      return ::getBranchTargetOpValue(MI, OpIdx,
+                                      ARM::fixup_arm_condbranch, Fixups);
+    return ::getBranchTargetOpValue(MI, OpIdx, 
+                                    ARM::fixup_arm_uncondbranch, Fixups);
+  }
 
-
+  return MO.getImm() >> 1;
+}
 
 /// getUnconditionalBranchTargetOpValue - Return encoding info for 24-bit
 /// immediate branch target.