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//===- X86RecognizableInstr.h - Disassembler instruction spec ----*- 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 X86 Disassembler Emitter.
// It contains the interface of a single recognizable instruction.
// Documentation for the disassembler emitter in general can be found in
// X86DisasemblerEmitter.h.
//
//===----------------------------------------------------------------------===//
#ifndef X86RECOGNIZABLEINSTR_H
#define X86RECOGNIZABLEINSTR_H
#include "X86DisassemblerTables.h"
#include "CodeGenTarget.h"
#include "Record.h"
#include "llvm/System/DataTypes.h"
#include "llvm/ADT/SmallVector.h"
namespace llvm {
namespace X86Disassembler {
/// RecognizableInstr - Encapsulates all information required to decode a single
/// instruction, as extracted from the LLVM instruction tables. Has methods
/// to interpret the information available in the LLVM tables, and to emit the
/// instruction into DisassemblerTables.
class RecognizableInstr {
private:
/// The opcode of the instruction, as used in an MCInst
InstrUID UID;
/// The record from the .td files corresponding to this instruction
const Record* Rec;
/// The prefix field from the record
uint8_t Prefix;
/// The opcode field from the record; this is the opcode used in the Intel
/// encoding and therefore distinct from the UID
uint8_t Opcode;
/// The form field from the record
uint8_t Form;
/// The segment override field from the record
uint8_t SegOvr;
/// The hasOpSizePrefix field from the record
bool HasOpSizePrefix;
/// The hasREX_WPrefix field from the record
bool HasREX_WPrefix;
/// The hasVEX_4VPrefix field from the record
bool HasVEX_4VPrefix;
/// The hasLockPrefix field from the record
bool HasLockPrefix;
/// The isCodeGenOnly filed from the record
bool IsCodeGenOnly;
/// The instruction name as listed in the tables
std::string Name;
/// The AT&T AsmString for the instruction
std::string AsmString;
/// Indicates whether the instruction is SSE
bool IsSSE;
/// Indicates whether the instruction has FR operands - MOVs with FR operands
/// are typically ignored
bool HasFROperands;
/// Indicates whether the instruction should be emitted into the decode
/// tables; regardless, it will be emitted into the instruction info table
bool ShouldBeEmitted;
/// The operands of the instruction, as listed in the CodeGenInstruction.
/// They are not one-to-one with operands listed in the MCInst; for example,
/// memory operands expand to 5 operands in the MCInst
const std::vector<CGIOperandList::OperandInfo>* Operands;
/// The description of the instruction that is emitted into the instruction
/// info table
InstructionSpecifier* Spec;
/// insnContext - Returns the primary context in which the instruction is
/// valid.
///
/// @return - The context in which the instruction is valid.
InstructionContext insnContext() const;
enum filter_ret {
FILTER_STRONG, // instruction has no place in the instruction tables
FILTER_WEAK, // instruction may conflict, and should be eliminated if
// it does
FILTER_NORMAL // instruction should have high priority and generate an
// error if it conflcits with any other FILTER_NORMAL
// instruction
};
/// filter - Determines whether the instruction should be decodable. Some
/// instructions are pure intrinsics and use unencodable operands; many
/// synthetic instructions are duplicates of other instructions; other
/// instructions only differ in the logical way in which they are used, and
/// have the same decoding. Because these would cause decode conflicts,
/// they must be filtered out.
///
/// @return - The degree of filtering to be applied (see filter_ret).
filter_ret filter() const;
/// typeFromString - Translates an operand type from the string provided in
/// the LLVM tables to an OperandType for use in the operand specifier.
///
/// @param s - The string, as extracted by calling Rec->getName()
/// on a CodeGenInstruction::OperandInfo.
/// @param isSSE - Indicates whether the instruction is an SSE
/// instruction. For SSE instructions, immediates are
/// fixed-size rather than being affected by the
/// mandatory OpSize prefix.
/// @param hasREX_WPrefix - Indicates whether the instruction has a REX.W
/// prefix. If it does, 32-bit register operands stay
/// 32-bit regardless of the operand size.
/// @param hasOpSizePrefix- Indicates whether the instruction has an OpSize
/// prefix. If it does not, then 16-bit register
/// operands stay 16-bit.
/// @return - The operand's type.
static OperandType typeFromString(const std::string& s,
bool isSSE,
bool hasREX_WPrefix,
bool hasOpSizePrefix);
/// immediateEncodingFromString - Translates an immediate encoding from the
/// string provided in the LLVM tables to an OperandEncoding for use in
/// the operand specifier.
///
/// @param s - See typeFromString().
/// @param hasOpSizePrefix - Indicates whether the instruction has an OpSize
/// prefix. If it does not, then 16-bit immediate
/// operands stay 16-bit.
/// @return - The operand's encoding.
static OperandEncoding immediateEncodingFromString(const std::string &s,
bool hasOpSizePrefix);
/// rmRegisterEncodingFromString - Like immediateEncodingFromString, but
/// handles operands that are in the REG field of the ModR/M byte.
static OperandEncoding rmRegisterEncodingFromString(const std::string &s,
bool hasOpSizePrefix);
/// rmRegisterEncodingFromString - Like immediateEncodingFromString, but
/// handles operands that are in the REG field of the ModR/M byte.
static OperandEncoding roRegisterEncodingFromString(const std::string &s,
bool hasOpSizePrefix);
static OperandEncoding memoryEncodingFromString(const std::string &s,
bool hasOpSizePrefix);
static OperandEncoding relocationEncodingFromString(const std::string &s,
bool hasOpSizePrefix);
static OperandEncoding opcodeModifierEncodingFromString(const std::string &s,
bool hasOpSizePrefix);
/// handleOperand - Converts a single operand from the LLVM table format to
/// the emitted table format, handling any duplicate operands it encounters
/// and then one non-duplicate.
///
/// @param optional - Determines whether to assert that the
/// operand exists.
/// @param operandIndex - The index into the generated operand table.
/// Incremented by this function one or more
/// times to reflect possible duplicate
/// operands).
/// @param physicalOperandIndex - The index of the current operand into the
/// set of non-duplicate ('physical') operands.
/// Incremented by this function once.
/// @param numPhysicalOperands - The number of non-duplicate operands in the
/// instructions.
/// @param operandMapping - The operand mapping, which has an entry for
/// each operand that indicates whether it is a
/// duplicate, and of what.
void handleOperand(bool optional,
unsigned &operandIndex,
unsigned &physicalOperandIndex,
unsigned &numPhysicalOperands,
unsigned *operandMapping,
OperandEncoding (*encodingFromString)
(const std::string&,
bool hasOpSizePrefix));
/// shouldBeEmitted - Returns the shouldBeEmitted field. Although filter()
/// filters out many instructions, at various points in decoding we
/// determine that the instruction should not actually be decodable. In
/// particular, MMX MOV instructions aren't emitted, but they're only
/// identified during operand parsing.
///
/// @return - true if at this point we believe the instruction should be
/// emitted; false if not. This will return false if filter() returns false
/// once emitInstructionSpecifier() has been called.
bool shouldBeEmitted() const {
return ShouldBeEmitted;
}
/// emitInstructionSpecifier - Loads the instruction specifier for the current
/// instruction into a DisassemblerTables.
///
/// @arg tables - The DisassemblerTables to populate with the specifier for
/// the current instruction.
void emitInstructionSpecifier(DisassemblerTables &tables);
/// emitDecodePath - Populates the proper fields in the decode tables
/// corresponding to the decode paths for this instruction.
///
/// @arg tables - The DisassemblerTables to populate with the decode
/// decode information for the current instruction.
void emitDecodePath(DisassemblerTables &tables) const;
/// Constructor - Initializes a RecognizableInstr with the appropriate fields
/// from a CodeGenInstruction.
///
/// @arg tables - The DisassemblerTables that the specifier will be added to.
/// @arg insn - The CodeGenInstruction to extract information from.
/// @arg uid - The unique ID of the current instruction.
RecognizableInstr(DisassemblerTables &tables,
const CodeGenInstruction &insn,
InstrUID uid);
public:
/// processInstr - Accepts a CodeGenInstruction and loads decode information
/// for it into a DisassemblerTables if appropriate.
///
/// @arg tables - The DiassemblerTables to be populated with decode
/// information.
/// @arg insn - The CodeGenInstruction to be used as a source for this
/// information.
/// @uid - The unique ID of the instruction.
static void processInstr(DisassemblerTables &tables,
const CodeGenInstruction &insn,
InstrUID uid);
};
} // namespace X86Disassembler
} // namespace llvm
#endif
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