Adding simple disassembler.

[colinl]

Summary

Adding a basic disassembler to use for testing instruction encoding bits.

[mcrosier]

lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp

72

Is Address used?

83

Same.

94

Same.

[colinl]

Removing unused parameter names.

lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp

72

Hmm I guess not. Removed the parameter name.

[sidneym]

lib/Target/Hexagon/HexagonInstrInfoV4.td

2133 ↗

(On Diff #15033)

The above could be removed and be submitted in another patch.

[colinl]

Removing .td file for later inclusion.

[• rafael]

Thanks a lot for working on this!

lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp

39

Don't repeat the name int the comment.

46

Don't repeat the name in the comment.

49

Missing override.

71

Start function names in lowercase.

[colinl]

Fixing up comments and adding override keyword.
Decode<Name>RegisterClass function names seem to be picked by tablegen.

[• rafael]

This is fine by me with a nit.

lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp

44

Why is this needed? MCDisassembler's destructor is virtual, so you should be able to just omit this.

[colinl]

Removing redundant virtual destructor.

[mcrosier]

Committed in r220393. Minor fixup in r220396.

lib/Target/Hexagon/CMakeLists.txt

 set(LLVM_TARGET_DEFINITIONS Hexagon.td)
 
+tablegen(LLVM HexagonGenDisassemblerTables.inc -gen-disassembler)
 tablegen(LLVM HexagonGenRegisterInfo.inc -gen-register-info)
 tablegen(LLVM HexagonGenInstrInfo.inc -gen-instr-info)
 tablegen(LLVM HexagonGenMCCodeEmitter.inc -gen-emitter)

 add_subdirectory(TargetInfo)
 add_subdirectory(InstPrinter)
 add_subdirectory(MCTargetDesc)
+add_subdirectory(Disassembler)
 

lib/Target/Hexagon/Disassembler/CMakeLists.txt

+add_llvm_library(LLVMHexagonDisassembler
+  HexagonDisassembler.cpp
+  )

lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp

+//===-- HexagonDisassembler.cpp - Disassembler for Hexagon ISA ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "MCTargetDesc/HexagonBaseInfo.h"
+#include "MCTargetDesc/HexagonMCTargetDesc.h"
+
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCDisassembler.h"
+#include "llvm/MC/MCExpr.h"
+#include "llvm/MC/MCFixedLenDisassembler.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCInstrDesc.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/MemoryObject.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/Support/Endian.h"
+
+#include <vector>
+#include <array>
+
+using namespace llvm;
+
+#define DEBUG_TYPE "hexagon-disassembler"
+
+using DecodeStatus = MCDisassembler::DecodeStatus;
+
+namespace {
+/// \brief Hexagon disassembler for all Hexagon platforms.
+class HexagonDisassembler : public MCDisassembler {
+public:
+  HexagonDisassembler(MCSubtargetInfo const &STI, MCContext &Ctx)
+      : MCDisassembler(STI, Ctx) {}
+
+  DecodeStatus getInstruction(MCInst &instr, uint64_t &size,
+                              MemoryObject const &region, uint64_t address,
+                              raw_ostream &vStream, raw_ostream &cStream) const override;
+};
+}
+
+static const uint16_t IntRegDecoderTable[] = {
+    Hexagon::R0,  Hexagon::R1,  Hexagon::R2,  Hexagon::R3,  Hexagon::R4,
+    Hexagon::R5,  Hexagon::R6,  Hexagon::R7,  Hexagon::R8,  Hexagon::R9,
+    Hexagon::R10, Hexagon::R11, Hexagon::R12, Hexagon::R13, Hexagon::R14,
+    Hexagon::R15, Hexagon::R16, Hexagon::R17, Hexagon::R18, Hexagon::R19,
+    Hexagon::R20, Hexagon::R21, Hexagon::R22, Hexagon::R23, Hexagon::R24,
+    Hexagon::R25, Hexagon::R26, Hexagon::R27, Hexagon::R28, Hexagon::R29,
+    Hexagon::R30, Hexagon::R31};
+
+static const uint16_t DoubleRegDecoderTable[] = {
+    Hexagon::D0,  Hexagon::D1,  Hexagon::D2,  Hexagon::D3,
+    Hexagon::D4,  Hexagon::D5,  Hexagon::D6,  Hexagon::D7,
+    Hexagon::D8,  Hexagon::D9,  Hexagon::D10, Hexagon::D11,
+    Hexagon::D12, Hexagon::D13, Hexagon::D14, Hexagon::D15};
+
+static const uint16_t PredRegDecoderTable[] = {Hexagon::P0, Hexagon::P1,
+                                               Hexagon::P2, Hexagon::P3};
+
+static DecodeStatus DecodeIntRegsRegisterClass(MCInst &Inst, unsigned RegNo,
+                                               uint64_t /*Address*/,
+                                               void const *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  unsigned Register = IntRegDecoderTable[RegNo];
+  Inst.addOperand(MCOperand::CreateReg(Register));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeDoubleRegsRegisterClass(MCInst &Inst, unsigned RegNo,
+                                                  uint64_t /*Address*/,
+                                                  void const *Decoder) {
+  if (RegNo > 15)
+    return MCDisassembler::Fail;
+
+  unsigned Register = DoubleRegDecoderTable[RegNo];
+  Inst.addOperand(MCOperand::CreateReg(Register));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodePredRegsRegisterClass(MCInst &Inst, unsigned RegNo,
+                                                uint64_t /*Address*/,
+                                                void const *Decoder) {
+  if (RegNo > 3)
+    return MCDisassembler::Fail;
+
+  unsigned Register = PredRegDecoderTable[RegNo];
+  Inst.addOperand(MCOperand::CreateReg(Register));
+  return MCDisassembler::Success;
+}
+
+#include "HexagonGenDisassemblerTables.inc"
+
+static MCDisassembler *createHexagonDisassembler(Target const &T,
+                                                 MCSubtargetInfo const &STI,
+                                                 MCContext &Ctx) {
+  return new HexagonDisassembler(STI, Ctx);
+}
+
+extern "C" void LLVMInitializeHexagonDisassembler() {
+  TargetRegistry::RegisterMCDisassembler(TheHexagonTarget,
+                                         createHexagonDisassembler);
+}
+
+DecodeStatus HexagonDisassembler::getInstruction(MCInst &MI, uint64_t &Size,
+                                                 MemoryObject const &Region,
+                                                 uint64_t Address,
+                                                 raw_ostream &os,
+                                                 raw_ostream &cs) const {
+  std::array<uint8_t, 4> Bytes;
+  Size = 4;
+  if (Region.readBytes(Address, Bytes.size(), Bytes.data()) == -1) {
+    return MCDisassembler::Fail;
+  }
+  uint32_t insn =
+      llvm::support::endian::read<uint32_t, llvm::support::little,
+                                  llvm::support::unaligned>(Bytes.data());
+
+  // Remove parse bits.
+  insn &= ~static_cast<uint32_t>(HexagonII::InstParseBits::INST_PARSE_MASK);
+  return decodeInstruction(DecoderTable32, MI, insn, Address, this, STI);
+}

lib/Target/Hexagon/Disassembler/LLVMBuild.txt

+;===-- ./lib/Target/Hexagon/Disassembler/LLVMBuild.txt ---------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = HexagonDisassembler
+parent = Hexagon
+required_libraries = HexagonDesc MCDisassembler HexagonInfo Support
+add_to_library_groups = Hexagon

lib/Target/Hexagon/Disassembler/Makefile

+##===-- lib/Target/Hexagon/Disassembler/Makefile -----------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../../..
+LIBRARYNAME = LLVMHexagonDisassembler
+
+# Hack: we need to include 'main' target directory to grab private headers
+CPP.Flags += -I$(PROJ_OBJ_DIR)/.. -I$(PROJ_SRC_DIR)/..
+
+include $(LEVEL)/Makefile.common

lib/Target/Hexagon/HexagonInstrFormats.td

   let Itinerary = itin;
   let Size = 4;
 
+  // SoftFail is a field the disassembler can use to provide a way for
+  // instructions to not match without killing the whole decode process. It is
+  // mainly used for ARM, but Tablegen expects this field to exist or it fails
+  // to build the decode table.
+  field bits<32> SoftFail = 0;
+
   // *** Must match MCTargetDesc/HexagonBaseInfo.h ***
 
   // Instruction type according to the ISA.

lib/Target/Hexagon/LLVMBuild.txt

 ;===------------------------------------------------------------------------===;
 
 [common]
-subdirectories = InstPrinter MCTargetDesc TargetInfo
+subdirectories = Disassembler InstPrinter MCTargetDesc TargetInfo
 
 [component_0]
 type = TargetGroup

lib/Target/Hexagon/MCTargetDesc/HexagonBaseInfo.h

 #include "HexagonMCTargetDesc.h"
 #include "llvm/Support/ErrorHandling.h"
 
+#include <stdint.h>
+
 namespace llvm {
 
 /// HexagonII - This namespace holds all of the target specific flags that

     MO_GPREL
   };
 
+  enum class InstParseBits : uint32_t {
+    INST_PARSE_MASK       = 0x0000c000,
+    INST_PARSE_PACKET_END = 0x0000c000,
+    INST_PARSE_LOOP_END   = 0x00008000,
+    INST_PARSE_NOT_END    = 0x00004000,
+    INST_PARSE_DUPLEX     = 0x00000000,
+    INST_PARSE_EXTENDER   = 0x00000000
+  };
+
 } // End namespace HexagonII.
 
 } // End namespace llvm.

lib/Target/Hexagon/Makefile

                 HexagonGenDAGISel.inc HexagonGenSubtargetInfo.inc \
                 HexagonGenCallingConv.inc \
                 HexagonGenDFAPacketizer.inc \
-                HexagonGenMCCodeEmitter.inc
+                HexagonGenMCCodeEmitter.inc \
+                HexagonGenDisassemblerTables.inc
 
-DIRS = InstPrinter TargetInfo MCTargetDesc
+DIRS = InstPrinter TargetInfo MCTargetDesc Disassembler
 
 include $(LEVEL)/Makefile.common