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116 lines
4.5 KiB
C++
116 lines
4.5 KiB
C++
// -*- mode: C++; c-file-style: "cc-mode" -*-
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//*************************************************************************
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// DESCRIPTION: Verilator: Passes over DfgGraph
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//
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// Code available from: https://verilator.org
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//
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//*************************************************************************
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//
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// Copyright 2003-2023 by Wilson Snyder. This program is free software; you
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// can redistribute it and/or modify it under the terms of either the GNU
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// Lesser General Public License Version 3 or the Perl Artistic License
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// Version 2.0.
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// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
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//
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//*************************************************************************
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#ifndef VERILATOR_V3DFGPASSES_H_
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#define VERILATOR_V3DFGPASSES_H_
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#include "config_build.h"
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#include "V3DfgPeephole.h"
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class AstModule;
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class DfgGraph;
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//===========================================================================
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// Various context objects hold data that need to persist across invocations
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// of a DFG pass.
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class V3DfgCseContext final {
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const std::string m_label; // Label to apply to stats
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public:
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VDouble0 m_eliminated; // Number of common sub-expressions eliminated
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explicit V3DfgCseContext(const std::string& label)
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: m_label{label} {}
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~V3DfgCseContext();
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};
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class DfgRemoveVarsContext final {
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const std::string m_label; // Label to apply to stats
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public:
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VDouble0 m_removed; // Number of redundant variables removed
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explicit DfgRemoveVarsContext(const std::string& label)
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: m_label{label} {}
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~DfgRemoveVarsContext();
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};
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class V3DfgOptimizationContext final {
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const std::string m_label; // Label to add to stats, etc.
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const std::string m_prefix; // Prefix to add to file dumps (derived from label)
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public:
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VDouble0 m_modules; // Number of modules optimized
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VDouble0 m_coalescedAssignments; // Number of partial assignments coalesced
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VDouble0 m_inputEquations; // Number of input combinational equations
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VDouble0 m_representable; // Number of combinational equations representable
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VDouble0 m_nonRepDType; // Equations non-representable due to data type
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VDouble0 m_nonRepImpure; // Equations non-representable due to impure node
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VDouble0 m_nonRepTiming; // Equations non-representable due to timing control
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VDouble0 m_nonRepLhs; // Equations non-representable due to lhs
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VDouble0 m_nonRepNode; // Equations non-representable due to node type
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VDouble0 m_nonRepUnknown; // Equations non-representable due to unknown node
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VDouble0 m_nonRepVarRef; // Equations non-representable due to variable reference
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VDouble0 m_nonRepWidth; // Equations non-representable due to width mismatch
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VDouble0 m_intermediateVars; // Number of intermediate variables introduced
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VDouble0 m_replacedVars; // Number of variables replaced
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VDouble0 m_resultEquations; // Number of result combinational equations
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V3DfgCseContext m_cseContext0{m_label + " 1st"};
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V3DfgCseContext m_cseContext1{m_label + " 2nd"};
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V3DfgPeepholeContext m_peepholeContext{m_label};
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DfgRemoveVarsContext m_removeVarsContext{m_label};
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explicit V3DfgOptimizationContext(const std::string& label);
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~V3DfgOptimizationContext();
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const std::string& prefix() const { return m_prefix; }
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};
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namespace V3DfgPasses {
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//===========================================================================
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// Top level entry points
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//===========================================================================
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// Construct a DfGGraph representing the combinational logic in the given AstModule. The logic
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// that is represented by the graph is removed from the given AstModule. Returns the
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// constructed DfgGraph.
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DfgGraph* astToDfg(AstModule&, V3DfgOptimizationContext&);
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// Optimize the given DfgGraph
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void optimize(DfgGraph&, V3DfgOptimizationContext&);
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// Convert DfgGraph back into Ast, and insert converted graph back into its parent module.
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// Returns the parent module.
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AstModule* dfgToAst(DfgGraph&, V3DfgOptimizationContext&);
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//===========================================================================
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// Intermediate/internal operations
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//===========================================================================
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// Common subexpression elimination
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void cse(DfgGraph&, V3DfgCseContext&);
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// Inline fully driven variables
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void inlineVars(const DfgGraph&);
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// Peephole optimizations
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void peephole(DfgGraph&, V3DfgPeepholeContext&);
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// Remove redundant variables
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void removeVars(DfgGraph&, DfgRemoveVarsContext&);
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// Remove unused nodes
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void removeUnused(DfgGraph&);
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} // namespace V3DfgPasses
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#endif
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