MCRegisterInfo.h

//=== MC/MCRegisterInfo.h - Target Register Description ---------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file describes an abstract interface used to get information about a
// target machines register file.  This information is used for a variety of
// purposed, especially register allocation.
//
//===----------------------------------------------------------------------===//

/* Capstone Disassembly Engine */
/* By Nguyen Anh Quynh <aquynh@gmail.com>, 2013-2019 */

#ifndef CS_LLVM_MC_MCREGISTERINFO_H
#define CS_LLVM_MC_MCREGISTERINFO_H

#include "capstone/platform.h"

/// An unsigned integer type large enough to represent all physical registers,
/// but not necessarily virtual registers.
typedef uint16_t MCPhysReg;
typedef const MCPhysReg* iterator;

typedef struct MCRegisterClass2 {
	iterator RegsBegin;
	const uint8_t *RegSet;
	uint8_t RegsSize;
	uint8_t RegSetSize;
} MCRegisterClass2;

typedef struct MCRegisterClass {
	iterator RegsBegin;
	const uint8_t *RegSet;
	uint16_t RegSetSize;
} MCRegisterClass;

/// MCRegisterDesc - This record contains information about a particular
/// register.  The SubRegs field is a zero terminated array of registers that
/// are sub-registers of the specific register, e.g. AL, AH are sub-registers
/// of AX. The SuperRegs field is a zero terminated array of registers that are
/// super-registers of AX.
typedef struct MCRegisterDesc {
	uint32_t Name;      // Printable name for the reg (for debugging)
	uint32_t SubRegs;   // Sub-register set, described above
	uint32_t SuperRegs; // Super-register set, described above

	// Offset into MCRI::SubRegIndices of a list of sub-register indices for each
	// sub-register in SubRegs.
	uint32_t SubRegIndices;

	// RegUnits - Points to the list of register units. The low 4 bits holds the
	// Scale, the high bits hold an offset into DiffLists. See MCRegUnitIterator.
	uint32_t RegUnits;

	/// Index into list with lane mask sequences. The sequence contains a lanemask
	/// for every register unit.
	uint16_t RegUnitLaneMasks;	// ???
} MCRegisterDesc;

/// MCRegisterInfo base class - We assume that the target defines a static
/// array of MCRegisterDesc objects that represent all of the machine
/// registers that the target has.  As such, we simply have to track a pointer
/// to this array so that we can turn register number into a register
/// descriptor.
///
/// Note this class is designed to be a base class of TargetRegisterInfo, which
/// is the interface used by codegen. However, specific targets *should never*
/// specialize this class. MCRegisterInfo should only contain getters to access
/// TableGen generated physical register data. It must not be extended with
/// virtual methods.
typedef struct MCRegisterInfo {
	const MCRegisterDesc *Desc;                 // Pointer to the descriptor array
	unsigned NumRegs;                           // Number of entries in the array
	unsigned RAReg;                             // Return address register
	unsigned PCReg;                             // Program counter register
	const MCRegisterClass *Classes;             // Pointer to the regclass array
	unsigned NumClasses;                        // Number of entries in the array
	unsigned NumRegUnits;                       // Number of regunits.
	uint16_t (*RegUnitRoots)[2];          // Pointer to regunit root table.
	const MCPhysReg *DiffLists;                 // Pointer to the difflists array
	// const LaneBitmask *RegUnitMaskSequences;    // Pointer to lane mask sequences
	const char *RegStrings;                     // Pointer to the string table.
	// const char *RegClassStrings;                // Pointer to the class strings.
	const uint16_t *SubRegIndices;              // Pointer to the subreg lookup
	// array.
	unsigned NumSubRegIndices;                  // Number of subreg indices.
	const uint16_t *RegEncodingTable;           // Pointer to array of register
	// encodings.
} MCRegisterInfo;

void MCRegisterInfo_InitMCRegisterInfo(MCRegisterInfo *RI,
		const MCRegisterDesc *D, unsigned NR, unsigned RA,
		unsigned PC,
		const MCRegisterClass *C, unsigned NC,
		uint16_t (*RURoots)[2],
		unsigned NRU,
		const MCPhysReg *DL,
		const char *Strings,
		const uint16_t *SubIndices,
		unsigned NumIndices,
		const uint16_t *RET);

unsigned MCRegisterInfo_getMatchingSuperReg(const MCRegisterInfo *RI, unsigned Reg, unsigned SubIdx, const MCRegisterClass *RC);

unsigned MCRegisterInfo_getSubReg(const MCRegisterInfo *RI, unsigned Reg, unsigned Idx);

const MCRegisterClass* MCRegisterInfo_getRegClass(const MCRegisterInfo *RI, unsigned i);

bool MCRegisterClass_contains(const MCRegisterClass *c, unsigned Reg);

#endif