llvm/llvm/utils/TableGen/Common/GlobalISel/Patterns.h

//===- Patterns.h ----------------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
/// \file Contains the Pattern hierarchy alongside helper classes such as
/// PatFrag, MIFlagsInfo, PatternType, etc.
///
/// These classes are used by the GlobalISel Combiner backend to help parse,
/// process and emit MIR patterns.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_UTILS_TABLEGEN_COMMON_GLOBALISEL_PATTERNS_H
#define LLVM_UTILS_TABLEGEN_COMMON_GLOBALISEL_PATTERNS_H

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Twine.h"
#include <memory>
#include <optional>
#include <string>

namespace llvm {

class Record;
class SMLoc;
class StringInit;
class CodeExpansions;
class CodeGenInstruction;
struct CodeGenIntrinsic;

namespace gi {

class CXXPredicateCode;
class LLTCodeGen;
class LLTCodeGenOrTempType;
class RuleMatcher;

//===- PatternType --------------------------------------------------------===//

struct VariadicPackTypeInfo { … };

/// Represent the type of a Pattern Operand.
///
/// Types have two form:
///   - LLTs, which are straightforward.
///   - Special types, e.g. GITypeOf, Variadic arguments list.
class PatternType { … };

//===- Pattern Base Class -------------------------------------------------===//

/// Base class for all patterns that can be written in an `apply`, `match` or
/// `pattern` DAG operator.
///
/// For example:
///
///     (apply (G_ZEXT $x, $y), (G_ZEXT $y, $z), "return isFoo(${z})")
///
/// Creates 3 Pattern objects:
///   - Two CodeGenInstruction Patterns
///   - A CXXPattern
class Pattern { … };

//===- AnyOpcodePattern ---------------------------------------------------===//

/// `wip_match_opcode` patterns.
/// This matches one or more opcodes, and does not check any operands
/// whatsoever.
///
/// TODO: Long-term, this needs to be removed. It's a hack around MIR
///       pattern matching limitations.
class AnyOpcodePattern : public Pattern { … };

//===- CXXPattern ---------------------------------------------------------===//

/// Represents raw C++ code which may need some expansions.
///
///   e.g. [{ return isFooBux(${src}.getReg()); }]
///
/// For the expanded code, \see CXXPredicateCode. CXXPredicateCode objects are
/// created through `expandCode`.
///
/// \see CodeExpander and \see CodeExpansions for more information on code
/// expansions.
///
/// This object has two purposes:
///   - Represent C++ code as a pattern entry.
///   - Be a factory for expanded C++ code.
///     - It's immutable and only holds the raw code so we can expand the same
///       CXX pattern multiple times if we need to.
///
/// Note that the code is always trimmed in the constructor, so leading and
/// trailing whitespaces are removed. This removes bloat in the output, avoids
/// formatting issues, but also allows us to check things like
/// `.startswith("return")` trivially without worrying about spaces.
class CXXPattern : public Pattern { … };

//===- InstructionPattern ---------------------------------------------===//

/// An operand for an InstructionPattern.
///
/// Operands are composed of three elements:
///   - (Optional) Value
///   - (Optional) Name
///   - (Optional) Type
///
/// Some examples:
///   (i32 0):$x -> V=int(0), Name='x', Type=i32
///   0:$x -> V=int(0), Name='x'
///   $x -> Name='x'
///   i32:$x -> Name='x', Type = i32
class InstructionOperand { … };

/// Base class for CodeGenInstructionPattern & PatFragPattern, which handles all
/// the boilerplate for patterns that have a list of operands for some (pseudo)
/// instruction.
class InstructionPattern : public Pattern { … };

//===- OperandTable -------------------------------------------------------===//

/// Maps InstructionPattern operands to their definitions. This allows us to tie
/// different patterns of a (apply), (match) or (patterns) set of patterns
/// together.
class OperandTable { … };

//===- MIFlagsInfo --------------------------------------------------------===//

/// Helper class to contain data associated with a MIFlags operand.
class MIFlagsInfo { … };

//===- CodeGenInstructionPattern ------------------------------------------===//

/// Matches an instruction or intrinsic:
///    e.g. `G_ADD $x, $y, $z` or `int_amdgcn_cos $a`
///
/// Intrinsics are just normal instructions with a special operand for intrinsic
/// ID. Despite G_INTRINSIC opcodes being variadic, we consider that the
/// Intrinsic's info takes priority. This means we return:
///   - false for isVariadic() and other variadic-related queries.
///   - getNumInstDefs and getNumInstOperands use the intrinsic's in/out
///   operands.
class CodeGenInstructionPattern : public InstructionPattern { … };

//===- OperandTypeChecker -------------------------------------------------===//

/// This is a trivial type checker for all operands in a set of
/// InstructionPatterns.
///
/// It infers the type of each operand, check it's consistent with the known
/// type of the operand, and then sets all of the types in all operands in
/// propagateTypes.
///
/// It also handles verifying correctness of special types.
class OperandTypeChecker { … };

//===- PatFrag ------------------------------------------------------------===//

/// Represents a parsed GICombinePatFrag. This can be thought of as the
/// equivalent of a CodeGenInstruction, but for PatFragPatterns.
///
/// PatFrags are made of 3 things:
///   - Out parameters (defs)
///   - In parameters
///   - A set of pattern lists (alternatives).
///
/// If the PatFrag uses instruction patterns, the root must be one of the defs.
///
/// Note that this DOES NOT represent the use of the PatFrag, only its
/// definition. The use of the PatFrag in a Pattern is represented by
/// PatFragPattern.
///
/// PatFrags use the term "parameter" instead of operand because they're
/// essentially macros, and using that name avoids confusion. Other than that,
/// they're structured similarly to a MachineInstruction  - all parameters
/// (operands) are in the same list, with defs at the start. This helps mapping
/// parameters to values, because, param N of a PatFrag is always operand N of a
/// PatFragPattern.
class PatFrag { … };

//===- PatFragPattern -----------------------------------------------------===//

/// Represents a use of a GICombinePatFrag.
class PatFragPattern : public InstructionPattern { … };

//===- BuiltinPattern -----------------------------------------------------===//

/// Represents builtin instructions such as "GIReplaceReg" and "GIEraseRoot".
enum BuiltinKind { … };

class BuiltinPattern : public InstructionPattern { … };

} // namespace gi
} // end namespace llvm

#endif // LLVM_UTILS_TABLEGEN_COMMON_GLOBALISEL_PATTERNS_H