Start incorporating the ARM integrated assembler.

src/IceAssemblerARM32.h

Index: src/IceAssemblerARM32.h
diff --git a/src/IceAssemblerARM32.h b/src/IceAssemblerARM32.h
index 2a42826df60df8a77d83bd45db72a1202445e95e..2b6bbb11d9e9ac48ce1498c258510419e1c9d5c2 100644
--- a/src/IceAssemblerARM32.h
+++ b/src/IceAssemblerARM32.h
@@ -24,8 +24,11 @@
 #define SUBZERO_SRC_ICEASSEMBLERARM32_H
 
 #include "IceAssembler.h"
+#include "IceConditionCodesARM32.h"
 #include "IceDefs.h"
 #include "IceFixups.h"
+#include "IceRegistersARM32.h"
+#include "IceTargetLowering.h"
 
 namespace Ice {
 namespace ARM32 {
@@ -35,15 +38,24 @@ class AssemblerARM32 : public Assembler {
   AssemblerARM32 &operator=(const AssemblerARM32 &) = delete;
 
 public:
-  explicit AssemblerARM32(bool use_far_branches = false)
-      : Assembler(Asm_ARM32) {
-    // This mode is only needed and implemented for MIPS and ARM.
-    assert(!use_far_branches);
+  explicit AssemblerARM32(GlobalContext *Ctx, bool use_far_branches = false)
+      : Assembler(Asm_ARM32, Ctx) {
+    // TODO(kschimpf): Add mode if needed when branches are handled.
     (void)use_far_branches;
   }
   ~AssemblerARM32() override = default;
 
-  void alignFunction() override { llvm_unreachable("Not yet implemented."); }
+  void alignFunction() override {
+    const SizeT Align = 1 << getBundleAlignLog2Bytes();
+    SizeT BytesNeeded = Utils::OffsetToAlignment(Buffer.getPosition(), Align);
+    constexpr SizeT InstSize = sizeof(int32_t);
+    assert(BytesNeeded % InstSize == 0);
+    while (BytesNeeded > 0) {
+      // TODO(kschimpf) Should this be NOP or some other instruction?
+      bkpt(0);
+      BytesNeeded -= InstSize;
+    }
+  }
 
   SizeT getBundleAlignLog2Bytes() const override { return 4; }
 
@@ -67,18 +79,173 @@ public:
   }
 
   void bindCfgNodeLabel(SizeT NodeNumber) override {
-    (void)NodeNumber;
-    llvm_unreachable("Not yet implemented.");
+    assert(!getPreliminary());
+    Label *L = getOrCreateCfgNodeLabel(NodeNumber);
+    this->bind(L);
   }
 
   bool fixupIsPCRel(FixupKind Kind) const override {
     (void)Kind;
     llvm_unreachable("Not yet implemented.");
   }
+  void bind(Label *label);
+
+  void bkpt(uint16_t imm16);
+
+  void bx(RegARM32::GPRRegister rm, CondARM32::Cond cond = CondARM32::AL);
 
   static bool classof(const Assembler *Asm) {
     return Asm->getKind() == Asm_ARM32;
   }
+
+private:
+  // Instruction encoding bits.
+
+  // halfword (or byte)
+  static constexpr uint32_t H = 1 << 5;
+  // load (or store)
+  static constexpr uint32_t L = 1 << 20;
+  // set condition code (or leave unchanged)
+  static constexpr uint32_t S = 1 << 20;
+  // writeback base register (or leave unchanged)
+  static constexpr uint32_t W = 1 << 21;
+  // accumulate in multiply instruction (or not)
+  static constexpr uint32_t A = 1 << 21;
+  // unsigned byte (or word)
+  static constexpr uint32_t B = 1 << 22;
+  // high/lo bit of start of s/d register range
+  static constexpr uint32_t D = 1 << 22;
+  // long (or short)
+  static constexpr uint32_t N = 1 << 22;
+  // positive (or negative) offset/index
+  static constexpr uint32_t U = 1 << 23;
+  // offset/pre-indexed addressing (or post-indexed addressing)
+  static constexpr uint32_t P = 1 << 24;
+  // immediate shifter operand (or not)
+  static constexpr uint32_t I = 1 << 25;
+
+  // The following define individual bits.
+  static constexpr uint32_t B0 = 1;
+  static constexpr uint32_t B1 = 1 << 1;
+  static constexpr uint32_t B2 = 1 << 2;
+  static constexpr uint32_t B3 = 1 << 3;
+  static constexpr uint32_t B4 = 1 << 4;
+  static constexpr uint32_t B5 = 1 << 5;
+  static constexpr uint32_t B6 = 1 << 6;
+  static constexpr uint32_t B7 = 1 << 7;
+  static constexpr uint32_t B8 = 1 << 8;
+  static constexpr uint32_t B9 = 1 << 9;
+  static constexpr uint32_t B10 = 1 << 10;
+  static constexpr uint32_t B11 = 1 << 11;
+  static constexpr uint32_t B12 = 1 << 12;
+  static constexpr uint32_t B16 = 1 << 16;
+  static constexpr uint32_t B17 = 1 << 17;
+  static constexpr uint32_t B18 = 1 << 18;
+  static constexpr uint32_t B19 = 1 << 19;
+  static constexpr uint32_t B20 = 1 << 20;
+  static constexpr uint32_t B21 = 1 << 21;
+  static constexpr uint32_t B22 = 1 << 22;
+  static constexpr uint32_t B23 = 1 << 23;
+  static constexpr uint32_t B24 = 1 << 24;
+  static constexpr uint32_t B25 = 1 << 25;
+  static constexpr uint32_t B26 = 1 << 26;
+  static constexpr uint32_t B27 = 1 << 27;
+
+  // Constants used for the decoding or encoding of the individual fields of
+  // instructions. Based on section A5.1 from the "ARM Architecture Reference
+  // Manual, ARMv7-A and ARMv7-R edition". See:
+  // http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0406c
+  static constexpr uint32_t kConditionShift = 28;
+  static constexpr uint32_t kConditionBits = 4;
+  static constexpr uint32_t kTypeShift = 25;
+  static constexpr uint32_t kTypeBits = 3;
+  static constexpr uint32_t kLinkShift = 24;
+  static constexpr uint32_t kLinkBits = 1;
+  static constexpr uint32_t kUShift = 23;
+  static constexpr uint32_t kUBits = 1;
+  static constexpr uint32_t kOpcodeShift = 21;
+  static constexpr uint32_t kOpcodeBits = 4;
+  static constexpr uint32_t kSShift = 20;
+  static constexpr uint32_t kSBits = 1;
+  static constexpr uint32_t kRnShift = 16;
+  static constexpr uint32_t kRnBits = 4;
+  static constexpr uint32_t kRdShift = 12;
+  static constexpr uint32_t kRdBits = 4;
+  static constexpr uint32_t kRsShift = 8;
+  static constexpr uint32_t kRsBits = 4;
+  static constexpr uint32_t kRmShift = 0;
+  static constexpr uint32_t kRmBits = 4;
+
+  // Immediate instruction fields encoding.
+  static constexpr uint32_t kRotateShift = 8;
+  static constexpr uint32_t kRotateBits = 4;
+  static constexpr uint32_t kImmed8Shift = 0;
+  static constexpr uint32_t kImmed8Bits = 8;
+
+  // Shift instruction register fields encodings.
+  static constexpr uint32_t kShiftImmShift = 7;
+  static constexpr uint32_t kShiftRegisterShift = 8;
+  static constexpr uint32_t kShiftImmBits = 5;
+  static constexpr uint32_t kShiftShift = 5;
+  static constexpr uint32_t kShiftBits = 2;
+
+  // Load/store instruction offset field encoding.
+  static constexpr uint32_t kOffset12Shift = 0;
+  static constexpr uint32_t kOffset12Bits = 12;
+  static constexpr uint32_t kOffset12Mask = 0x00000fff;
+
+  // Mul instruction register field encodings.
+  static constexpr uint32_t kMulRdShift = 16;
+  static constexpr uint32_t kMulRdBits = 4;
+  static constexpr uint32_t kMulRnShift = 12;
+  static constexpr uint32_t kMulRnBits = 4;
+
+  // Div instruction register field encodings.
+  static constexpr uint32_t kDivRdShift = 16;
+  static constexpr uint32_t kDivRdBits = 4;
+  static constexpr uint32_t kDivRmShift = 8;
+  static constexpr uint32_t kDivRmBints = 4;
+  static constexpr uint32_t kDivRnShift = 0;
+  static constexpr uint32_t kDivRnBits = 4;
+
+  // ldrex/strex register field encodings.
+  static constexpr uint32_t kLdExRnShift = 16;
+  static constexpr uint32_t kLdExRtShift = 12;
+  static constexpr uint32_t kStrExRnShift = 16;
+  static constexpr uint32_t kStrExRdShift = 12;
+  static constexpr uint32_t kStrExRtShift = 0;
+
+  // MRC instruction offset field encoding.
+  static constexpr uint32_t kCRmShift = 0;
+  static constexpr uint32_t kCRmBits = 4;
+  static constexpr uint32_t kOpc2Shift = 5;
+  static constexpr uint32_t kOpc2Bits = 3;
+  static constexpr uint32_t kCoprocShift = 8;
+  static constexpr uint32_t kCoprocBits = 4;
+  static constexpr uint32_t kCRnShift = 16;
+  static constexpr uint32_t kCRnBits = 4;
+  static constexpr uint32_t kOpc1Shift = 21;
+  static constexpr uint32_t kOpc1Bits = 3;
+
+  static constexpr uint32_t kBranchOffsetMask = 0x00ffffff;
+
+  // A vector of pool-allocated x86 labels for CFG nodes.
+  using LabelVector = std::vector<Label *>;
+  LabelVector CfgNodeLabels;
+
+  Label *getOrCreateLabel(SizeT Number, LabelVector &Labels);
+  Label *getOrCreateCfgNodeLabel(SizeT NodeNumber) {
+    return getOrCreateLabel(NodeNumber, CfgNodeLabels);
+  }
+
+  void emitInt32(int32_t Value) { Buffer.emit<int32_t>(Value); }
+
+  static int32_t BkptEncoding(uint16_t imm16) {
+    // bkpt requires that the cond field is AL.
+    // cccc00010010iiiiiiiiiiii0111iiii where cccc=AL and i in imm16
+    return (CondARM32::AL << kConditionShift) | B24 | B21 |
+           ((imm16 >> 4) << 8) | B6 | B5 | B4 | (imm16 & 0xf);
+  }
 };
 
 } // end of namespace ARM32