ARM: validate immediate branch targets in AsmParser.

Immediate branch targets aren't commonly used, but if they are we should make
sure they can actually be encoded. This means they must be divisible by 2 when
targeting Thumb mode, and by 4 when targeting ARM mode.

Also do a little naming cleanup while I was changing everything around anyway.

llvm-svn: 275116

5 files changed, 93 insertions, 51 deletions

diff --git a/llvm/lib/Target/ARM/ARMInstrInfo.td b/llvm/lib/Target/ARM/ARMInstrInfo.td
index e2a66eb56cf..060376b0a27 100644
--- a/llvm/lib/Target/ARM/ARMInstrInfo.td
+++ b/llvm/lib/Target/ARM/ARMInstrInfo.td
@@ -418,34 +418,35 @@ def brtarget : Operand<OtherVT> {
   let DecoderMethod = "DecodeT2BROperand";
 }
 
-// FIXME: get rid of this one?
-def uncondbrtarget : Operand<OtherVT> {
-  let EncoderMethod = "getUnconditionalBranchTargetOpValue";
-  let OperandType = "OPERAND_PCREL";
+// Branches targeting ARM-mode must be divisible by 4 if they're a raw
+// immediate.
+def ARMBranchTarget : AsmOperandClass {
+  let Name = "ARMBranchTarget";
 }
 
-// Branch target for ARM. Handles conditional/unconditional
-def br_target : Operand<OtherVT> {
-  let EncoderMethod = "getARMBranchTargetOpValue";
-  let OperandType = "OPERAND_PCREL";
+// Branches targeting Thumb-mode must be divisible by 2 if they're a raw
+// immediate.
+def ThumbBranchTarget : AsmOperandClass {
+  let Name = "ThumbBranchTarget";
 }
 
-// Call target.
-// FIXME: rename bltarget to t2_bl_target?
-def bltarget : Operand<i32> {
-  // Encoded the same as branch targets.
-  let EncoderMethod = "getBranchTargetOpValue";
+def arm_br_target : Operand<OtherVT> {
+  let ParserMatchClass = ARMBranchTarget;
+  let EncoderMethod = "getARMBranchTargetOpValue";
   let OperandType = "OPERAND_PCREL";
 }
 
 // Call target for ARM. Handles conditional/unconditional
 // FIXME: rename bl_target to t2_bltarget?
-def bl_target : Operand<i32> {
+def arm_bl_target : Operand<i32> {
+  let ParserMatchClass = ARMBranchTarget;
   let EncoderMethod = "getARMBLTargetOpValue";
   let OperandType = "OPERAND_PCREL";
 }
 
-def blx_target : Operand<i32> {
+// Target for BLX *from* ARM mode.
+def arm_blx_target : Operand<i32> {
+  let ParserMatchClass = ThumbBranchTarget;
   let EncoderMethod = "getARMBLXTargetOpValue";
   let OperandType = "OPERAND_PCREL";
 }
@@ -2208,7 +2209,7 @@ let isCall = 1,
   // at least be a pseudo instruction expanding to the predicated version
   // at MC lowering time.
   Defs = [LR], Uses = [SP] in {
-  def BL  : ABXI<0b1011, (outs), (ins bl_target:$func),
+  def BL  : ABXI<0b1011, (outs), (ins arm_bl_target:$func),
                 IIC_Br, "bl\t$func",
                 [(ARMcall tglobaladdr:$func)]>,
             Requires<[IsARM]>, Sched<[WriteBrL]> {
@@ -2218,7 +2219,7 @@ let isCall = 1,
     let DecoderMethod = "DecodeBranchImmInstruction";
   }
 
-  def BL_pred : ABI<0b1011, (outs), (ins bl_target:$func),
+  def BL_pred : ABI<0b1011, (outs), (ins arm_bl_target:$func),
                    IIC_Br, "bl", "\t$func",
                    [(ARMcall_pred tglobaladdr:$func)]>,
                 Requires<[IsARM]>, Sched<[WriteBrL]> {
@@ -2259,7 +2260,7 @@ let isCall = 1,
 
   // mov lr, pc; b if callee is marked noreturn to avoid confusing the
   // return stack predictor.
-  def BMOVPCB_CALL : ARMPseudoInst<(outs), (ins bl_target:$func),
+  def BMOVPCB_CALL : ARMPseudoInst<(outs), (ins arm_bl_target:$func),
                                8, IIC_Br, [(ARMcall_nolink tglobaladdr:$func)]>,
                       Requires<[IsARM]>, Sched<[WriteBr]>;
 }
@@ -2267,7 +2268,7 @@ let isCall = 1,
 let isBranch = 1, isTerminator = 1 in {
   // FIXME: should be able to write a pattern for ARMBrcond, but can't use
   // a two-value operand where a dag node expects two operands. :(
-  def Bcc : ABI<0b1010, (outs), (ins br_target:$target),
+  def Bcc : ABI<0b1010, (outs), (ins arm_br_target:$target),
                IIC_Br, "b", "\t$target",
                [/*(ARMbrcond bb:$target, imm:$cc, CCR:$ccr)*/]>,
                Sched<[WriteBr]>  {
@@ -2282,8 +2283,9 @@ let isBranch = 1, isTerminator = 1 in {
     // FIXME: We shouldn't need this pseudo at all. Just using Bcc directly
     // should be sufficient.
     // FIXME: Is B really a Barrier? That doesn't seem right.
-    def B : ARMPseudoExpand<(outs), (ins br_target:$target), 4, IIC_Br,
-                [(br bb:$target)], (Bcc br_target:$target, (ops 14, zero_reg))>,
+    def B : ARMPseudoExpand<(outs), (ins arm_br_target:$target), 4, IIC_Br,
+                [(br bb:$target)], (Bcc arm_br_target:$target,
+                (ops 14, zero_reg))>,
                 Sched<[WriteBr]>;
 
     let Size = 4, isNotDuplicable = 1, isIndirectBranch = 1 in {
@@ -2310,7 +2312,7 @@ let isBranch = 1, isTerminator = 1 in {
 }
 
 // BLX (immediate)
-def BLXi : AXI<(outs), (ins blx_target:$target), BrMiscFrm, NoItinerary,
+def BLXi : AXI<(outs), (ins arm_blx_target:$target), BrMiscFrm, NoItinerary,
                "blx\t$target", []>,
            Requires<[IsARM, HasV5T]>, Sched<[WriteBrL]> {
   let Inst{31-25} = 0b1111101;
@@ -2340,9 +2342,9 @@ let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1, Uses = [SP] in {
   def TCRETURNri : PseudoInst<(outs), (ins tcGPR:$dst), IIC_Br, []>,
                    Sched<[WriteBr]>;
 
-  def TAILJMPd : ARMPseudoExpand<(outs), (ins br_target:$dst),
+  def TAILJMPd : ARMPseudoExpand<(outs), (ins arm_br_target:$dst),
                                  4, IIC_Br, [],
-                                 (Bcc br_target:$dst, (ops 14, zero_reg))>,
+                                 (Bcc arm_br_target:$dst, (ops 14, zero_reg))>,
                                  Requires<[IsARM]>, Sched<[WriteBr]>;
 
   def TAILJMPr : ARMPseudoExpand<(outs), (ins tcGPR:$dst),
diff --git a/llvm/lib/Target/ARM/ARMInstrThumb.td b/llvm/lib/Target/ARM/ARMInstrThumb.td
index 5d4698f6a8b..bec1ea8763d 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb.td
@@ -125,26 +125,38 @@ def t_adrlabel : Operand<i32> {
   let ParserMatchClass = UnsignedOffset_b8s2;
 }
 
-def t_bcctarget : Operand<i32> {
-  let EncoderMethod = "getThumbBCCTargetOpValue";
-  let DecoderMethod = "DecodeThumbBCCTargetOperand";
-}
 
-def t_cbtarget : Operand<i32> {
-  let EncoderMethod = "getThumbCBTargetOpValue";
-  let DecoderMethod = "DecodeThumbCmpBROperand";
+def thumb_br_target : Operand<OtherVT> {
+  let ParserMatchClass = ThumbBranchTarget;
+  let EncoderMethod = "getThumbBranchTargetOpValue";
+  let OperandType = "OPERAND_PCREL";
 }
 
-def t_bltarget : Operand<i32> {
+def thumb_bl_target : Operand<i32> {
+  let ParserMatchClass = ThumbBranchTarget;
   let EncoderMethod = "getThumbBLTargetOpValue";
   let DecoderMethod = "DecodeThumbBLTargetOperand";
 }
 
-def t_blxtarget : Operand<i32> {
+// Target for BLX *from* thumb mode.
+def thumb_blx_target : Operand<i32> {
+  let ParserMatchClass = ARMBranchTarget;
   let EncoderMethod = "getThumbBLXTargetOpValue";
   let DecoderMethod = "DecodeThumbBLXOffset";
 }
 
+def thumb_bcc_target : Operand<OtherVT> {
+  let ParserMatchClass = ThumbBranchTarget;
+  let EncoderMethod = "getThumbBCCTargetOpValue";
+  let DecoderMethod = "DecodeThumbBCCTargetOperand";
+}
+
+def thumb_cb_target : Operand<OtherVT> {
+  let ParserMatchClass = ThumbBranchTarget;
+  let EncoderMethod = "getThumbCBTargetOpValue";
+  let DecoderMethod = "DecodeThumbCmpBROperand";
+}
+
 // t_addrmode_pc := <label> => pc + imm8 * 4
 //
 def t_addrmode_pc : MemOperand {
@@ -471,7 +483,7 @@ let isCall = 1,
   Defs = [LR], Uses = [SP] in {
   // Also used for Thumb2
   def tBL  : TIx2<0b11110, 0b11, 1,
-                  (outs), (ins pred:$p, t_bltarget:$func), IIC_Br,
+                  (outs), (ins pred:$p, thumb_bl_target:$func), IIC_Br,
                   "bl${p}\t$func",
                   [(ARMcall tglobaladdr:$func)]>,
              Requires<[IsThumb]>, Sched<[WriteBrL]> {
@@ -485,7 +497,7 @@ let isCall = 1,
 
   // ARMv5T and above, also used for Thumb2
   def tBLXi : TIx2<0b11110, 0b11, 0,
-                 (outs), (ins pred:$p, t_blxtarget:$func), IIC_Br,
+                 (outs), (ins pred:$p, thumb_blx_target:$func), IIC_Br,
                    "blx${p}\t$func", []>,
               Requires<[IsThumb, HasV5T, IsNotMClass]>, Sched<[WriteBrL]> {
     bits<24> func;
@@ -540,8 +552,9 @@ let isBranch = 1, isTerminator = 1, isBarrier = 1 in {
   // Just a pseudo for a tBL instruction. Needed to let regalloc know about
   // the clobber of LR.
   let Defs = [LR] in
-  def tBfar : tPseudoExpand<(outs), (ins t_bltarget:$target, pred:$p),
-                          4, IIC_Br, [], (tBL pred:$p, t_bltarget:$target)>,
+  def tBfar : tPseudoExpand<(outs), (ins thumb_bl_target:$target, pred:$p),
+                          4, IIC_Br, [],
+                          (tBL pred:$p, thumb_bl_target:$target)>,
                           Sched<[WriteBrTbl]>;
 
   def tBR_JTr : tPseudoInst<(outs),
@@ -557,7 +570,7 @@ 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 t_bcctarget:$target, pred:$p), IIC_Br,
+  def tBcc : T1I<(outs), (ins thumb_bcc_target:$target, pred:$p), IIC_Br,
                  "b${p}\t$target",
                  [/*(ARMbrcond bb:$target, imm:$cc)*/]>,
              T1BranchCond<{1,1,0,1}>, Sched<[WriteBr]> {
diff --git a/llvm/lib/Target/ARM/ARMInstrThumb2.td b/llvm/lib/Target/ARM/ARMInstrThumb2.td
index 93fde91d9d2..55e5308be40 100644
--- a/llvm/lib/Target/ARM/ARMInstrThumb2.td
+++ b/llvm/lib/Target/ARM/ARMInstrThumb2.td
@@ -3524,7 +3524,7 @@ def t2LDMIA_RET: t2PseudoExpand<(outs GPR:$wb), (ins GPR:$Rn, pred:$p,
 
 let isBranch = 1, isTerminator = 1, isBarrier = 1 in {
 let isPredicable = 1 in
-def t2B   : T2I<(outs), (ins uncondbrtarget:$target), IIC_Br,
+def t2B   : T2I<(outs), (ins thumb_br_target:$target), IIC_Br,
                  "b", ".w\t$target",
                  [(br bb:$target)]>, Sched<[WriteBr]>,
                  Requires<[IsThumb, HasV8MBaseline]> {
@@ -3617,9 +3617,9 @@ let isCall = 1, isTerminator = 1, isReturn = 1, isBarrier = 1 in {
   // IOS version.
   let Uses = [SP] in
   def tTAILJMPd: tPseudoExpand<(outs),
-                   (ins uncondbrtarget:$dst, pred:$p),
+                   (ins thumb_br_target:$dst, pred:$p),
                    4, IIC_Br, [],
-                   (t2B uncondbrtarget:$dst, pred:$p)>,
+                   (t2B thumb_br_target:$dst, pred:$p)>,
                  Requires<[IsThumb2, IsMachO]>, Sched<[WriteBr]>;
 }
 
@@ -3655,7 +3655,7 @@ def t2BXJ : T2I<(outs), (ins GPRnopc:$func), NoItinerary, "bxj", "\t$func", []>,
 
 // Compare and branch on zero / non-zero
 let isBranch = 1, isTerminator = 1 in {
-  def tCBZ  : T1I<(outs), (ins tGPR:$Rn, t_cbtarget:$target), IIC_Br,
+  def tCBZ  : T1I<(outs), (ins tGPR:$Rn, thumb_cb_target:$target), IIC_Br,
                   "cbz\t$Rn, $target", []>,
               T1Misc<{0,0,?,1,?,?,?}>,
               Requires<[IsThumb, HasV8MBaseline]>, Sched<[WriteBr]> {
@@ -3667,7 +3667,7 @@ let isBranch = 1, isTerminator = 1 in {
     let Inst{2-0} = Rn;
   }
 
-  def tCBNZ : T1I<(outs), (ins tGPR:$Rn, t_cbtarget:$target), IIC_Br,
+  def tCBNZ : T1I<(outs), (ins tGPR:$Rn, thumb_cb_target:$target), IIC_Br,
                   "cbnz\t$Rn, $target", []>,
               T1Misc<{1,0,?,1,?,?,?}>,
               Requires<[IsThumb, HasV8MBaseline]>, Sched<[WriteBr]> {
diff --git a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
index b3b0dffb6c9..d368e2349b3 100644
--- a/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ b/llvm/lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -676,6 +676,24 @@ public:
   bool isImm() const override {
     return Kind == k_Immediate;
   }
+
+  bool isARMBranchTarget() const {
+    if (!isImm()) return false;
+
+    if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(getImm()))
+      return CE->getValue() % 4 == 0;
+    return true;
+  }
+
+
+  bool isThumbBranchTarget() const {
+    if (!isImm()) return false;
+
+    if (const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(getImm()))
+      return CE->getValue() % 2 == 0;
+    return true;
+  }
+
   // checks whether this operand is an unsigned offset which fits is a field
   // of specified width and scaled by a specific number of bits
   template<unsigned width, unsigned scale>
@@ -1728,6 +1746,16 @@ public:
       Inst.addOperand(MCOperand::createExpr(Expr));
   }
 
+  void addARMBranchTargetOperands(MCInst &Inst, unsigned N) const {
+    assert(N == 1 && "Invalid number of operands!");
+    addExpr(Inst, getImm());
+  }
+
+  void addThumbBranchTargetOperands(MCInst &Inst, unsigned N) const {
+    assert(N == 1 && "Invalid number of operands!");
+    addExpr(Inst, getImm());
+  }
+
   void addCondCodeOperands(MCInst &Inst, unsigned N) const {
     assert(N == 2 && "Invalid number of operands!");
     Inst.addOperand(MCOperand::createImm(unsigned(getCondCode())));
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
index 1b40655fbe1..9fca13eeea9 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCCodeEmitter.cpp
@@ -120,11 +120,11 @@ public:
                                   SmallVectorImpl<MCFixup> &Fixups,
                                   const MCSubtargetInfo &STI) const;
 
-  /// getUnconditionalBranchTargetOpValue - Return encoding info for 24-bit
+  /// getThumbBranchTargetOpValue - Return encoding info for 24-bit
   /// immediate Thumb2 direct branch target.
-  uint32_t getUnconditionalBranchTargetOpValue(const MCInst &MI, unsigned OpIdx,
-                                  SmallVectorImpl<MCFixup> &Fixups,
-                                  const MCSubtargetInfo &STI) const;
+  uint32_t getThumbBranchTargetOpValue(const MCInst &MI, unsigned OpIdx,
+                                       SmallVectorImpl<MCFixup> &Fixups,
+                                       const MCSubtargetInfo &STI) const;
 
   /// getARMBranchTargetOpValue - Return encoding info for 24-bit immediate
   /// branch target.
@@ -750,10 +750,9 @@ getARMBLXTargetOpValue(const MCInst &MI, unsigned OpIdx,
 
 /// getUnconditionalBranchTargetOpValue - Return encoding info for 24-bit
 /// immediate branch target.
-uint32_t ARMMCCodeEmitter::
-getUnconditionalBranchTargetOpValue(const MCInst &MI, unsigned OpIdx,
-                       SmallVectorImpl<MCFixup> &Fixups,
-                       const MCSubtargetInfo &STI) const {
+uint32_t ARMMCCodeEmitter::getThumbBranchTargetOpValue(
+    const MCInst &MI, unsigned OpIdx, SmallVectorImpl<MCFixup> &Fixups,
+    const MCSubtargetInfo &STI) const {
   unsigned Val = 0;
   const MCOperand MO = MI.getOperand(OpIdx);