verilator/src/V3WidthCommit.cpp

538 lines
24 KiB
C++

// -*- mode: C++; c-file-style: "cc-mode" -*-
//*************************************************************************
// DESCRIPTION: Verilator: Commit expression widths
//
// Code available from: https://verilator.org
//
//*************************************************************************
//
// Copyright 2003-2025 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
//
//*************************************************************************
//
// Remove all $signed, $unsigned, we're done with them.
//
// This step is only called on real V3Width, not intermediate e.g. widthParams
//
//*************************************************************************
#include "V3PchAstNoMT.h" // VL_MT_DISABLED_CODE_UNIT
#include "config_build.h"
#include "verilatedos.h"
#include "V3WidthCommit.h"
#include "V3MemberMap.h"
VL_DEFINE_DEBUG_FUNCTIONS;
//######################################################################
// Now that all widthing is complete,
// Copy all width() to widthMin(). V3Const expects this
class WidthCommitVisitor final : public VNVisitor {
// NODE STATE
// AstVar::user1p -> bool, processed
// AstNodeFTask::user2() -> int. Non-zero if ever referenced (called)
// AstNew::user2() -> int. Count of number of references, minus references in
// functions never called
const VNUser1InUse m_inuser1;
const VNUser2InUse m_inuser2;
// STATE
AstNodeFTask* m_ftaskp = nullptr; // Current function/task
AstNodeModule* m_modp = nullptr; // Current module
std::string m_contNba; // In continuous- or non-blocking assignment
bool m_dynsizedelem
= false; // Writing a dynamically-sized array element, not the array itself
VMemberMap m_memberMap; // Member names cached for fast lookup
bool m_taskRefWarn = true; // Allow task reference warnings
bool m_underSel = false; // Under AstMemberSel or AstSel
bool m_underAlwaysEdged = false; // Under always with sequential SenTree
std::vector<AstNew*> m_virtualNewsp; // Instantiations of virtual classes
std::vector<AstNodeFTask*> m_tasksp; // All the tasks, we will check if they are ever called
public:
// METHODS
VL_DEFINE_DEBUG_FUNCTIONS;
private:
// METHODS
void editDType(AstNode* nodep) {
// Called by every visitor. Edit dtypes for this node, also check for some warnings
nodep->dtypep(editOneDType(nodep->dtypep()));
if (m_ftaskp && m_ftaskp->verilogFunction() && m_taskRefWarn && nodep->isTimingControl())
nodep->v3warn(
FUNCTIMECTL,
"Functions cannot contain time-controlling statements (IEEE 1800-2023 13.4)\n"
<< nodep->warnContextPrimary() << "\n"
<< nodep->warnMore() << "... Suggest make caller 'function "
<< m_ftaskp->prettyName() << "' a task\n"
<< m_ftaskp->warnContextSecondary());
}
AstNodeDType* editOneDType(AstNodeDType* nodep) {
// See if the dtype/refDType can be converted to a standard one
// This reduces the number of dtypes in the system, and since
// dtypep() figures into sameTree() results in better optimizations
if (!nodep) return nullptr;
// Recurse to handle the data type, as may change the size etc of this type
if (!nodep->user1()) iterate(nodep);
// Look for duplicate
if (AstBasicDType* const bdtypep = VN_CAST(nodep, BasicDType)) {
AstBasicDType* const newp = nodep->findInsertSameDType(bdtypep);
if (newp != bdtypep && debug() >= 9) {
UINFO_PREFIX("dtype replacement ");
nodep->dumpSmall(std::cout);
std::cout << " ----> ";
newp->dumpSmall(std::cout);
std::cout << std::endl;
}
return newp;
}
return nodep;
}
void classEncapCheck(AstNode* nodep, AstNode* defp, AstClass* defClassp) {
// Check local/protected status and complain
bool local = false;
bool prot = false;
if (!defp) {
// rand_mode() / constraint_mode() handled in V3Randomize
UASSERT_OBJ(nodep->name() == "rand_mode" || nodep->name() == "constraint_mode", nodep,
"Only rand_mode() and constraint_mode() can have no def");
return;
}
if (const auto anodep = VN_CAST(defp, Var)) {
local = anodep->isHideLocal();
prot = anodep->isHideProtected();
} else if (const auto anodep = VN_CAST(defp, NodeFTask)) {
local = anodep->isHideLocal();
prot = anodep->isHideProtected();
} else if (const auto anodep = VN_CAST(defp, Typedef)) {
local = anodep->isHideLocal();
prot = anodep->isHideProtected();
} else {
nodep->v3fatalSrc("ref to unhandled definition type " << defp->prettyTypeName());
}
if (local || prot) {
const auto refClassp = VN_CAST(m_modp, Class);
const char* how = nullptr;
// Inner nested classes can access `local` or `protected` members of their outer class
const auto nestedAccess = [refClassp](const AstClass*, const AstNode* memberp) {
return memberp == refClassp;
};
if (local && defClassp
&& ((refClassp != defClassp) && !(defClassp->existsMember(nestedAccess)))) {
how = "'local'";
} else if (prot && defClassp && !AstClass::isClassExtendedFrom(refClassp, defClassp)
&& !(defClassp->existsMember(nestedAccess))) {
how = "'protected'";
}
if (how) {
UINFO(9, "refclass " << refClassp);
UINFO(9, "defclass " << defClassp);
nodep->v3warn(ENCAPSULATED, nodep->prettyNameQ()
<< " is hidden as " << how
<< " within this context (IEEE 1800-2023 8.18)\n"
<< nodep->warnContextPrimary() << "\n"
<< nodep->warnOther()
<< "... Location of definition\n"
<< defp->warnContextSecondary());
}
}
}
void varLifetimeCheck(AstNode* nodep, AstVar* varp) {
// Skip if we are under a member select (lhs of a dot)
// We don't care about lifetime of anything else than rhs of a dot
if (!m_underSel && !m_contNba.empty()) {
std::string varType;
const AstNodeDType* const varDtp = varp->dtypep()->skipRefp();
if (varp->lifetime().isAutomatic() && !VN_IS(varDtp, IfaceRefDType)
&& !(varp->isFuncLocal() && varp->isIO()))
varType = "Automatic lifetime";
else if (varp->isClassMember() && !varp->lifetime().isStatic()
&& !VN_IS(varDtp, IfaceRefDType))
varType = "Class non-static";
else if (varDtp->isDynamicallySized() && m_dynsizedelem)
varType = "Dynamically-sized";
if (!varType.empty()) {
UINFO(1, " Related var dtype: " << varDtp);
nodep->v3error(varType
<< " variable not allowed in " << m_contNba
<< " assignment (IEEE 1800-2023 6.21): " << varp->prettyNameQ());
}
}
}
void deadCheckTasks() {
for (AstNodeFTask* taskp : m_tasksp) {
if (!taskp->user2()) {
taskp->foreach([](AstNew* newp) { newp->user2Inc(-1); });
}
}
for (AstNew* newp : m_virtualNewsp) {
if (newp->user2() > 0)
newp->v3error("Illegal to call 'new' using an abstract virtual class "
+ AstNode::prettyNameQ(newp->classOrPackagep()->origName())
+ " (IEEE 1800-2023 8.21)");
}
}
// VISITORS
void visit(AstNodeModule* nodep) override {
VL_RESTORER(m_modp);
m_modp = nodep;
iterateChildren(nodep);
editDType(nodep);
if (AstClass* const classp = VN_CAST(nodep, Class)) {
for (AstClassExtends* extendsp = classp->extendsp(); extendsp;
extendsp = extendsp->classp()->extendsp()) {
const AstClass* const ebasep = extendsp->classp();
if (ebasep->baseOverride().isFinal()) {
extendsp->v3error("Class " << nodep->prettyNameQ()
<< " is being extended from class marked ':final'"
" (IEEE 1800-2023 8.20)\n"
<< extendsp->warnContextPrimary() << "\n"
<< ebasep->warnOther()
<< "... Location of ':final' class being extended\n"
<< ebasep->warnContextSecondary());
}
}
}
}
void visit(AstAlways* nodep) override {
// As have not optimized SenTrees yet, an 'always .*' will be on first and only SenItem
if (nodep->sentreep() && nodep->sentreep()->sensesp()
&& nodep->sentreep()->sensesp()->isComboStar()) {
const bool noReads = nodep->forall(
[&](const AstNodeVarRef* refp) { return !refp->access().isReadOrRW(); });
if (noReads) {
nodep->v3warn(ALWNEVER, "'always @*' will never execute as expression list is "
"empty (no variables read)\n"
<< nodep->warnMore()
<< "... Suggest use 'always_comb'");
VL_DO_DANGLING(pushDeletep(nodep->unlinkFrBack()), nodep);
return;
}
}
VL_RESTORER(m_underAlwaysEdged);
m_underAlwaysEdged
= nodep->sentreep() && nodep->sentreep()->sensesp() && nodep->sentreep()->hasEdge();
// Iterate will delete ComboStar sentrees, so after above
iterateChildren(nodep);
editDType(nodep);
}
void visit(AstFork* nodep) override {
VL_RESTORER(m_taskRefWarn);
// fork..join_any is allowed to call tasks, and UVM does this
if (!nodep->isTimingControl()) m_taskRefWarn = false;
iterateChildren(nodep);
editDType(nodep);
}
void visit(AstSenTree* nodep) override {
if (nodep->sensesp() && nodep->sensesp()->isComboStar()) {
UASSERT_OBJ(!nodep->sensesp()->nextp(), nodep, "Shouldn't be senitems after .*");
// Make look like standalone always
// (Rest of code assumed this before .* existed)
VL_DO_DANGLING(pushDeletep(nodep->unlinkFrBack()), nodep);
return;
}
iterateChildren(nodep);
editDType(nodep);
}
void visit(AstAttrOf* nodep) override {
switch (nodep->attrType()) {
case VAttrType::FUNC_ARG_PROTO: // FALLTHRU
case VAttrType::FUNC_RETURN_PROTO:
VL_DO_DANGLING(pushDeletep(nodep->unlinkFrBack()), nodep);
return;
default:;
}
iterateChildren(nodep);
editDType(nodep);
}
void visit(AstClassExtends* nodep) override {
if (nodep->user1SetOnce()) return; // Process once
// Extend arguments were converted to super.new arguments in V3LinkDot
if (nodep->argsp()) pushDeletep(nodep->argsp()->unlinkFrBackWithNext());
iterateChildren(nodep);
}
void visit(AstConst* nodep) override {
if (nodep->user1SetOnce()) return; // Process once
UASSERT_OBJ(nodep->dtypep(), nodep, "No dtype");
iterate(nodep->dtypep()); // Do datatype first
if (AstConst* const newp = V3WidthCommit::newIfConstCommitSize(nodep)) {
nodep->replaceWith(newp);
AstNode* const oldp = nodep;
nodep = newp;
// UINFOTREE(5, oldp, "", "fixConstSize_old");
// UINFOTREE(5, newp, "", "_new");
VL_DO_DANGLING(pushDeletep(oldp), oldp);
}
editDType(nodep);
}
void visit(AstCastWrap* nodep) override {
iterateChildren(nodep);
editDType(nodep);
UINFO(6, " Replace " << nodep << " w/ " << nodep->lhsp());
nodep->replaceWith(nodep->lhsp()->unlinkFrBack());
VL_DO_DANGLING(pushDeletep(nodep), nodep);
}
void visit(AstConstraint* nodep) override {
iterateChildren(nodep);
editDType(nodep);
{
const AstClass* const classp = VN_CAST(m_modp, Class);
if (nodep->isKwdPure()
&& (!classp || (!classp->isInterfaceClass() && !classp->isVirtual()))) {
nodep->v3error("Illegal to have 'pure constraint' in non-abstract class"
" (IEEE 1800-2023 18.5.2)");
}
}
}
void visit(AstNodeDType* nodep) override {
// Note some specific dtypes have unique visitors
visitIterateNodeDType(nodep);
}
void visit(AstNodeUOrStructDType* nodep) override {
if (nodep->user1SetOnce()) return; // Process once
visitIterateNodeDType(nodep);
}
void visit(AstEnumDType* nodep) override {
nodep->tableMap().clear(); // Only needed up through V3Width process
visitIterateNodeDType(nodep);
}
void visit(AstParamTypeDType* nodep) override {
if (nodep->user1SetOnce()) return; // Process once
visitIterateNodeDType(nodep);
// Move to type table as all dtype pointers must resolve there
nodep->unlinkFrBack(); // Make non-child
v3Global.rootp()->typeTablep()->addTypesp(nodep);
}
void visit(AstRefDType* nodep) override {
visitIterateNodeDType(nodep);
if (!nodep->typedefp()) return; // Already checked and cleared
classEncapCheck(nodep, nodep->typedefp(), VN_CAST(nodep->classOrPackagep(), Class));
nodep->typedefp(nullptr); // No longer needed
}
void visitIterateNodeDType(AstNodeDType* nodep) {
// Rather than use dtypeChg which may make new nodes, we edit in place,
// as we don't need to preserve any widthMin's, and every dtype with the same width
// gets an identical edit.
if (nodep->user1SetOnce()) return; // Process once
nodep->widthMinFromWidth();
// Too late to any unspecified sign to be anything but unsigned
if (nodep->numeric().isNosign()) nodep->numeric(VSigning::UNSIGNED);
iterateChildren(nodep);
nodep->virtRefDTypep(editOneDType(nodep->virtRefDTypep()));
nodep->virtRefDType2p(editOneDType(nodep->virtRefDType2p()));
}
void visit(AstNodeFTask* nodep) override {
if (!nodep->taskPublic() && !nodep->dpiExport() && !nodep->dpiImport())
m_tasksp.push_back(nodep);
VL_RESTORER(m_ftaskp);
m_ftaskp = nodep;
iterateChildren(nodep);
editDType(nodep);
{
const AstClass* const classp = VN_CAST(m_modp, Class);
if (nodep->classMethod() && nodep->pureVirtual() && classp
&& !classp->isInterfaceClass() && !classp->isVirtual()) {
nodep->v3error(
"Illegal to have 'pure virtual' in non-virtual class (IEEE 1800-2023 8.21)");
}
}
bool extended = false;
if (const AstClass* const classp = VN_CAST(m_modp, Class)) {
for (AstClassExtends* extendsp = classp->extendsp(); extendsp;
extendsp = extendsp->classp()->extendsp()) {
const AstClass* const eclassp = extendsp->classp();
if (AstNodeFTask* const fbasep
= VN_CAST(m_memberMap.findMember(eclassp, nodep->name()), NodeFTask)) {
if (fbasep != nodep) {
extended = true;
if (nodep->baseOverride().isInitial()) {
nodep->v3error("Member "
<< nodep->prettyNameQ()
<< " is marked ':initial' but is being extended"
" (IEEE 1800-2023 8.20)\n"
<< nodep->warnContextPrimary() << "\n"
<< fbasep->warnOther()
<< "... Location of declaration being extended\n"
<< fbasep->warnContextSecondary());
}
if (fbasep->baseOverride().isFinal()) {
nodep->v3error(
"Member "
<< nodep->prettyNameQ()
<< " is being extended from member marked ':final'"
" (IEEE 1800-2023 8.20)\n"
<< nodep->warnContextPrimary() << "\n"
<< fbasep->warnOther()
<< "... Location of ':final' declaration being extended\n"
<< fbasep->warnContextSecondary());
}
}
}
}
}
if (!extended && nodep->baseOverride().isExtends()) {
nodep->v3error("Member " << nodep->prettyNameQ()
<< " marked ':extends' but no base class function is"
" being extend (IEEE 1800-2023 8.20)");
}
}
void visit(AstNodeVarRef* nodep) override {
iterateChildren(nodep);
editDType(nodep);
classEncapCheck(nodep, nodep->varp(), VN_CAST(nodep->classOrPackagep(), Class));
if (nodep->access().isWriteOrRW()) varLifetimeCheck(nodep, nodep->varp());
}
void visit(AstAssign* nodep) override {
iterateChildren(nodep);
editDType(nodep);
// Lint
if (m_underAlwaysEdged) {
const bool ignore = nodep->lhsp()->forall([&](const AstVarRef* refp) {
// Ignore reads (e.g.: index expressions)
if (refp->access().isReadOnly()) return true;
const AstVar* const varp = refp->varp();
// Ignore ...
return varp->isUsedLoopIdx() // ... loop indices
|| varp->isTemp() // ... temporaries
|| varp->fileline()->warnIsOff(V3ErrorCode::BLKSEQ); // ... user said so
});
if (!ignore) {
nodep->v3warn(BLKSEQ,
"Blocking assignment '=' in sequential logic process\n"
<< nodep->warnMore() //
<< "... Suggest using delayed assignment '<='");
}
}
}
void visit(AstAssignDly* nodep) override {
iterateAndNextNull(nodep->timingControlp());
iterateAndNextNull(nodep->rhsp());
{
VL_RESTORER(m_contNba);
m_contNba = "nonblocking";
iterateAndNextNull(nodep->lhsp());
}
editDType(nodep);
}
void visit(AstAssignW* nodep) override {
iterateAndNextNull(nodep->timingControlp());
iterateAndNextNull(nodep->rhsp());
{
VL_RESTORER(m_contNba);
m_contNba = "continuous";
iterateAndNextNull(nodep->lhsp());
}
editDType(nodep);
}
void visit(AstNodeFTaskRef* nodep) override {
iterateChildren(nodep);
editDType(nodep);
classEncapCheck(nodep, nodep->taskp(), VN_CAST(nodep->classOrPackagep(), Class));
if (nodep->taskp() && nodep->taskp()->verilogTask() && m_ftaskp
&& m_ftaskp->verilogFunction() && m_taskRefWarn) {
nodep->v3warn(FUNCTIMECTL,
"Functions cannot invoke tasks (IEEE 1800-2023 13.4)\n"
<< nodep->warnContextPrimary() << "\n"
<< nodep->warnMore() << "... Suggest make caller 'function "
<< m_ftaskp->prettyName() << "' a task\n"
<< m_ftaskp->warnContextSecondary() << "\n"
<< nodep->warnMore() << "... Or, suggest make called 'task "
<< nodep->taskp()->prettyName() << "' a function void\n"
<< nodep->taskp()->warnContextSecondary());
}
if (nodep->taskp()) nodep->taskp()->user2(1);
if (AstNew* const newp = VN_CAST(nodep, New)) {
if (!VN_IS(newp->backp(), Assign)) return;
if (AstClass* const classp = VN_CAST(newp->classOrPackagep(), Class)) {
if (classp->isVirtual() || classp->isInterfaceClass()) {
m_virtualNewsp.push_back(newp);
newp->user2Inc();
}
}
}
}
void visit(AstMemberSel* nodep) override {
{
VL_RESTORER(m_underSel);
m_underSel = true;
iterateChildren(nodep);
}
editDType(nodep);
if (auto* const classrefp = VN_CAST(nodep->fromp()->dtypep(), ClassRefDType)) {
classEncapCheck(nodep, nodep->varp(), classrefp->classp());
} // else might be struct, etc
varLifetimeCheck(nodep, nodep->varp());
}
void visit(AstVar* nodep) override {
iterateChildren(nodep);
editDType(nodep);
if (nodep->isFuncLocal() && nodep->direction() == VDirection::INPUT && nodep->valuep()) {
// It's the default value of optional argument.
// Such values are added to function calls in V3Width so can be removed now
pushDeletep(nodep->valuep()->unlinkFrBack());
}
}
void visit(AstNodePreSel* nodep) override { // LCOV_EXCL_LINE
// This check could go anywhere after V3Param
nodep->v3fatalSrc("Presels should have been removed before this point");
}
void visit(AstCMethodHard* nodep) override {
VL_RESTORER(m_dynsizedelem);
if (nodep->method() == VCMethod::ARRAY_AT || nodep->method() == VCMethod::ARRAY_AT_WRITE
|| nodep->method() == VCMethod::DYN_AT_WRITE_APPEND)
m_dynsizedelem = true;
iterateChildren(nodep);
editDType(nodep);
}
void visit(AstAssocSel* nodep) override {
VL_RESTORER(m_dynsizedelem);
m_dynsizedelem = true;
iterateChildren(nodep);
editDType(nodep);
}
void visit(AstSel* nodep) override {
{
VL_RESTORER(m_underSel);
m_underSel = true;
iterateChildren(nodep);
}
editDType(nodep);
}
void visit(AstNode* nodep) override {
iterateChildren(nodep);
editDType(nodep);
}
public:
// CONSTRUCTORS
explicit WidthCommitVisitor(AstNetlist* nodep) {
// Were changing widthMin's, so the table is now somewhat trashed
nodep->typeTablep()->clearCache();
iterate(nodep);
deadCheckTasks();
// Don't want to AstTypeTable::repairCache, as all needed nodes
// have been added back in; a repair would prevent dead nodes from
// being detected
}
~WidthCommitVisitor() override = default;
};
//######################################################################
// V3WidthCommit class functions
void V3WidthCommit::widthCommit(AstNetlist* nodep) {
UINFO(2, __FUNCTION__ << ":");
{ WidthCommitVisitor{nodep}; } // Destruct before checking
V3Global::dumpCheckGlobalTree("widthcommit", 0, dumpTreeEitherLevel() >= 6);
}