action.h

/*
 * SPDX-FileCopyrightText: 2013 Barefoot Networks, Inc.
 * Copyright 2013-present Barefoot Networks, Inc.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
 
#ifndef BACKENDS_BMV2_COMMON_ACTION_H_
#define BACKENDS_BMV2_COMMON_ACTION_H_
 
#include "helpers.h"
#include "ir/ir.h"
 
namespace P4::BMV2 {

struct JumpLabelInfo {
    // The number of jump labels that have been created so far, for
    // the current action where we are generating its primitives.
    // Jump labels are allocated starting from 0 and incrementing from
    // there.
    int numLabels;
    // The jump label that is positioned at the end of the action
    // body.  This is needed if we wish to implement a 'return' or
    // 'exit' statement within a conditionally executed part of an
    // action body, to jump to the end of the action.
    int labelIdEndOfAction;
    // Label ID for the end of the innermost enclosing loop (break target).
    // -1 means we are not inside any loop.
    int labelIdBreak = -1;
    // Label ID for the update section of the innermost enclosing loop (continue target).
    // -1 means we are not inside any loop.
    int labelIdContinue = -1;
    // Let F be the set of offsets in the action that contain a
    // primitive "_jump" or _jump_if_zero".  For each offset f in F,
    // offsetToTargetLabelId[f] is the label ID to which the primitive
    // should jump.
    std::map<unsigned int, unsigned int> offsetToTargetLabelId;
    // For each offset f in F, offsetToJumpParams[f] is the array
    // of parameters that should be used as operands to the primitive,
    // except for the offset, which will only be added at the end of
    // method convertActionBodyTop.
    std::map<unsigned int, Util::JsonArray *> offsetToJumpParams;
    // labelIdToJumpOffset[labelId] equal to offset means that the
    // position of that labelId within the array of primitives for an
    // action is 'offset'.  _jump and _jump_if_zero primitive actions
    // must use 'offset' as their offset parameter in order to jump to
    // that primitive.
    std::map<unsigned int, unsigned int> labelIdToJumpOffset;
};
 
class ActionConverter : public Inspector {
    ConversionContext *ctxt;
 
    void convertActionBodyTop(const IR::Vector<IR::StatOrDecl> *body, Util::JsonArray *result);
    void convertActionBody(const IR::Vector<IR::StatOrDecl> *body, Util::JsonArray *result,
                           bool inConditional, JumpLabelInfo *info);
    void convertActionParams(const IR::ParameterList *parameters, Util::JsonArray *params);
    cstring jsonAssignment(const IR::Type *type);
    void postorder(const IR::P4Action *action) override;
 
 public:
    const bool emitExterns;
    explicit ActionConverter(ConversionContext *ctxt, const bool &emitExterns_)
        : ctxt(ctxt), emitExterns(emitExterns_) {
        setName("ConvertActions");
    }
};
 
}  // namespace P4::BMV2
 
#endif /* BACKENDS_BMV2_COMMON_ACTION_H_ */