[AVR] Add the machine code disassembler
This adds a super basic implementation of a machine code disassembler.
It doesn't support any operands with custom encoding.
llvm-svn: 284930
diff --git a/llvm/lib/Target/AVR/Disassembler/AVRDisassembler.cpp b/llvm/lib/Target/AVR/Disassembler/AVRDisassembler.cpp
new file mode 100644
index 0000000..ae87d64
--- /dev/null
+++ b/llvm/lib/Target/AVR/Disassembler/AVRDisassembler.cpp
@@ -0,0 +1,160 @@
+//===- AVRDisassembler.cpp - Disassembler for AVR ---------------*- C++ -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the AVR Disassembler.
+//
+//===----------------------------------------------------------------------===//
+
+#include "AVR.h"
+#include "AVRRegisterInfo.h"
+#include "AVRSubtarget.h"
+#include "MCTargetDesc/AVRMCTargetDesc.h"
+
+#include "llvm/MC/MCDisassembler/MCDisassembler.h"
+#include "llvm/MC/MCFixedLenDisassembler.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCContext.h"
+#include "llvm/MC/MCAsmInfo.h"
+#include "llvm/Support/TargetRegistry.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "avr-disassembler"
+
+typedef MCDisassembler::DecodeStatus DecodeStatus;
+
+namespace {
+
+/// A disassembler class for AVR.
+class AVRDisassembler : public MCDisassembler {
+public:
+ AVRDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
+ : MCDisassembler(STI, Ctx) {}
+ virtual ~AVRDisassembler() {}
+
+ DecodeStatus getInstruction(MCInst &Instr, uint64_t &Size,
+ ArrayRef<uint8_t> Bytes, uint64_t Address,
+ raw_ostream &VStream,
+ raw_ostream &CStream) const override;
+};
+}
+
+namespace llvm {
+extern Target TheAVRTarget;
+}
+
+static MCDisassembler *createAVRDisassembler(const Target &T,
+ const MCSubtargetInfo &STI,
+ MCContext &Ctx) {
+ return new AVRDisassembler(STI, Ctx);
+}
+
+
+extern "C" void LLVMInitializeAVRDisassembler() {
+ // Register the disassembler.
+ TargetRegistry::RegisterMCDisassembler(TheAVRTarget,
+ createAVRDisassembler);
+}
+
+static DecodeStatus DecodeGPR8RegisterClass(MCInst &Inst, unsigned RegNo,
+ uint64_t Address, const void *Decoder) {
+ return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeLD8RegisterClass(MCInst &Inst, unsigned RegNo,
+ uint64_t Address, const void *Decoder) {
+ return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodePTRREGSRegisterClass(MCInst &Inst, unsigned RegNo,
+ uint64_t Address, const void *Decoder) {
+ return MCDisassembler::Success;
+}
+
+#include "AVRGenDisassemblerTables.inc"
+
+static DecodeStatus readInstruction16(ArrayRef<uint8_t> Bytes, uint64_t Address,
+ uint64_t &Size, uint32_t &Insn) {
+ if (Bytes.size() < 2) {
+ Size = 0;
+ return MCDisassembler::Fail;
+ }
+
+ Size = 2;
+ Insn = (Bytes[0] << 0) | (Bytes[1] << 8);
+
+ return MCDisassembler::Success;
+}
+
+static DecodeStatus readInstruction32(ArrayRef<uint8_t> Bytes, uint64_t Address,
+ uint64_t &Size, uint32_t &Insn) {
+
+ if (Bytes.size() < 4) {
+ Size = 0;
+ return MCDisassembler::Fail;
+ }
+
+ Size = 4;
+ Insn = (Bytes[0] << 0) | (Bytes[1] << 8) | (Bytes[2] << 16) | (Bytes[3] << 24);
+
+ return MCDisassembler::Success;
+}
+
+static const uint8_t *getDecoderTable(uint64_t Size) {
+
+ switch (Size) {
+ case 2: return DecoderTable16;
+ case 4: return DecoderTable32;
+ default: llvm_unreachable("instructions must be 16 or 32-bits");
+ }
+}
+
+DecodeStatus AVRDisassembler::getInstruction(MCInst &Instr, uint64_t &Size,
+ ArrayRef<uint8_t> Bytes,
+ uint64_t Address,
+ raw_ostream &VStream,
+ raw_ostream &CStream) const {
+ uint32_t Insn;
+
+ DecodeStatus Result;
+
+ // Try decode a 16-bit instruction.
+ {
+ Result = readInstruction16(Bytes, Address, Size, Insn);
+
+ if (Result == MCDisassembler::Fail) return MCDisassembler::Fail;
+
+ // Try to auto-decode a 16-bit instruction.
+ Result = decodeInstruction(getDecoderTable(Size), Instr,
+ Insn, Address, this, STI);
+
+ if (Result != MCDisassembler::Fail)
+ return Result;
+ }
+
+ // Try decode a 32-bit instruction.
+ {
+ Result = readInstruction32(Bytes, Address, Size, Insn);
+
+ if (Result == MCDisassembler::Fail) return MCDisassembler::Fail;
+
+ Result = decodeInstruction(getDecoderTable(Size), Instr, Insn,
+ Address, this, STI);
+
+ if (Result != MCDisassembler::Fail) {
+ return Result;
+ }
+
+ return MCDisassembler::Fail;
+ }
+}
+
+typedef DecodeStatus (*DecodeFunc)(MCInst &MI, unsigned insn, uint64_t Address,
+ const void *Decoder);
+