verilator/src/V3DepthBlock.cpp

126 lines
4.4 KiB
C++

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Prevent very deep expressions
//
// Code available from: https://verilator.org
//
//*************************************************************************
//
// Copyright 2003-2024 by Wilson Snyder. This program is free software; you
// can redistribute it and/or modify it under the terms of either the GNU
// Lesser General Public License Version 3 or the Perl Artistic License
// Version 2.0.
// SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
//
//*************************************************************************
// V3DepthBlock's Transformations:
//
// Each module:
// For each deep block, create cfunc including that block.
//
//*************************************************************************
#include "V3PchAstNoMT.h" // VL_MT_DISABLED_CODE_UNIT
#include "V3DepthBlock.h"
#include "V3EmitCBase.h"
VL_DEFINE_DEBUG_FUNCTIONS;
//######################################################################
class DepthBlockVisitor final : public VNVisitor {
// NODE STATE
// STATE
const AstNodeModule* m_modp = nullptr; // Current module
const AstCFunc* m_cfuncp = nullptr; // Current function
int m_depth = 0; // How deep in an expression
int m_deepNum = 0; // How many functions made
// METHODS
AstCFunc* createDeepFunc(AstNodeStmt* nodep) {
VNRelinker relinkHandle;
nodep->unlinkFrBack(&relinkHandle);
// Create sub function
AstScope* const scopep = m_cfuncp->scopep();
const string name = m_cfuncp->name() + "__deep" + cvtToStr(++m_deepNum);
AstCFunc* const funcp = new AstCFunc{nodep->fileline(), name, scopep};
funcp->slow(m_cfuncp->slow());
funcp->isStatic(m_cfuncp->isStatic());
funcp->isLoose(m_cfuncp->isLoose());
funcp->addStmtsp(nodep);
scopep->addBlocksp(funcp);
// Call sub function at the point where the body was removed from
AstCCall* const callp = new AstCCall{nodep->fileline(), funcp};
callp->dtypeSetVoid();
if (VN_IS(m_modp, Class)) {
funcp->argTypes(EmitCBase::symClassVar());
callp->argTypes("vlSymsp");
}
UINFO(6, " New " << callp << endl);
relinkHandle.relink(callp->makeStmt());
// Done
return funcp;
}
// VISITORS
void visit(AstNodeModule* nodep) override {
UINFO(4, " MOD " << nodep << endl);
VL_RESTORER(m_modp);
{
m_modp = nodep;
m_deepNum = 0;
iterateChildren(nodep);
}
}
void visit(AstCFunc* nodep) override {
// We recurse into this.
VL_RESTORER(m_depth);
VL_RESTORER(m_cfuncp);
{
m_depth = 0;
m_cfuncp = nodep;
iterateChildren(nodep);
}
}
void visit(AstStmtExpr* nodep) override {} // Stop recursion after introducing new function
void visit(AstJumpBlock*) override {} // Stop recursion as can't break up across a jump
void visit(AstNodeStmt* nodep) override {
m_depth++;
if (m_depth > v3Global.opt.compLimitBlocks()) { // Already done
UINFO(4, "DeepBlocks " << m_depth << " " << nodep << endl);
const AstNode* const backp = nodep->backp(); // Only for debug
if (debug() >= 9) backp->dumpTree("- pre : ");
AstCFunc* const funcp = createDeepFunc(nodep);
iterate(funcp);
if (debug() >= 9) backp->dumpTree("- post: ");
if (debug() >= 9) funcp->dumpTree("- func: ");
} else {
iterateChildren(nodep);
}
m_depth--;
}
void visit(AstNodeExpr*) override {} // Accelerate
//--------------------
void visit(AstVar*) override {} // Don't hit varrefs under vars
void visit(AstNode* nodep) override { iterateChildren(nodep); }
public:
// CONSTRUCTORS
explicit DepthBlockVisitor(AstNetlist* nodep) { iterate(nodep); }
~DepthBlockVisitor() override = default;
};
//######################################################################
// DepthBlock class functions
void V3DepthBlock::depthBlockAll(AstNetlist* nodep) {
UINFO(2, __FUNCTION__ << ": " << endl);
{ DepthBlockVisitor{nodep}; } // Destruct before checking
V3Global::dumpCheckGlobalTree("deepblock", 0, dumpTreeEitherLevel() >= 3);
}