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typeChecker.cpp
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typeChecker.cpp
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/*
Copyright 2013-present Barefoot Networks, Inc.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#include "typeChecker.h"
#include "frontends/common/constantFolding.h"
#include "frontends/common/resolveReferences/resolveReferences.h"
#include "frontends/p4/coreLibrary.h"
#include "frontends/p4/enumInstance.h"
#include "frontends/p4/methodInstance.h"
#include "frontends/p4/toP4/toP4.h"
#include "lib/algorithm.h"
#include "lib/log.h"
#include "syntacticEquivalence.h"
#include "typeConstraints.h"
#include "typeSubstitution.h"
#include "typeUnification.h"
namespace P4 {
namespace {
// Used to set the type of Constants after type inference
class ConstantTypeSubstitution : public Transform {
TypeVariableSubstitution *subst;
TypeMap *typeMap;
TypeInference *tc;
public:
ConstantTypeSubstitution(TypeVariableSubstitution *subst, ReferenceMap *, TypeMap *typeMap,
TypeInference *tc)
: subst(subst), typeMap(typeMap), tc(tc) {
CHECK_NULL(subst);
CHECK_NULL(typeMap);
CHECK_NULL(tc);
LOG3("ConstantTypeSubstitution " << subst);
}
#if 0
// If two Type_InfInt types have been unified, we replace
// one of them with the other.
const IR::Node *postorder(IR::Type_InfInt* type) override {
auto repl = subst->get(type);
if (!repl)
return type;
while (repl->is<IR::Type_Var>()) {
auto next = subst->get(repl->to<IR::ITypeVar>());
BUG_CHECK(next != repl, "Cycle in substitutions: %1%", next);
if (!next) break;
repl = next;
}
LOG2("Replacing " << type << " with " << repl);
return repl;
}
#endif
const IR::Node *postorder(IR::Constant *cst) override {
auto cstType = typeMap->getType(getOriginal(), true);
if (!cstType->is<IR::ITypeVar>()) return cst;
auto repl = cstType;
while (repl->is<IR::ITypeVar>()) {
auto next = subst->get(repl->to<IR::ITypeVar>());
BUG_CHECK(next != repl, "Cycle in substitutions: %1%", next);
if (!next) break;
repl = next;
}
if (repl != cstType) {
// We may replace a type variable with another one
LOG2("Inferred type " << repl << " for " << cst);
cst = new IR::Constant(cst->srcInfo, repl, cst->value, cst->base);
} else {
LOG2("No type inferred for " << cst << " repl is " << repl);
}
return cst;
}
const IR::Expression *convert(const IR::Expression *expr) {
auto result = expr->apply(*this)->to<IR::Expression>();
if (result != expr && (::errorCount() == 0)) tc->learn(result, this);
return result;
}
const IR::Vector<IR::Expression> *convert(const IR::Vector<IR::Expression> *vec) {
auto result = vec->apply(*this)->to<IR::Vector<IR::Expression>>();
if (result != vec) tc->learn(result, this);
return result;
}
const IR::Vector<IR::Argument> *convert(const IR::Vector<IR::Argument> *vec) {
auto result = vec->apply(*this)->to<IR::Vector<IR::Argument>>();
if (result != vec) tc->learn(result, this);
return result;
}
};
} // namespace
TypeChecking::TypeChecking(ReferenceMap *refMap, TypeMap *typeMap, bool updateExpressions) {
addPasses({new P4::ResolveReferences(refMap), new P4::TypeInference(refMap, typeMap, true),
updateExpressions ? new ApplyTypesToExpressions(typeMap) : nullptr,
updateExpressions ? new P4::ResolveReferences(refMap) : nullptr});
setStopOnError(true);
}
//////////////////////////////////////////////////////////////////////////
bool TypeInference::learn(const IR::Node *node, Visitor *caller) {
auto *learner = clone();
learner->setCalledBy(caller);
unsigned previous = ::errorCount();
(void)node->apply(*learner);
unsigned errCount = ::errorCount();
bool result = errCount > previous;
if (result) typeError("Error while analyzing %1%", node);
return result;
}
const IR::Expression *TypeInference::constantFold(const IR::Expression *expression) {
if (readOnly) return expression;
DoConstantFolding cf(refMap, typeMap, false);
auto result = expression->apply(cf);
LOG3("Folded " << expression << " into " << result);
return result;
}
// Make a clone of the type where all type variables in
// the type parameters are replaced with fresh ones.
// This should only be applied to canonical types.
const IR::Type *TypeInference::cloneWithFreshTypeVariables(const IR::IMayBeGenericType *type) {
TypeVariableSubstitution tvs;
for (auto v : type->getTypeParameters()->parameters) {
auto tv = new IR::Type_Var(v->srcInfo, v->getName());
bool b = tvs.setBinding(v, tv);
BUG_CHECK(b, "%1%: failed replacing %2% with %3%", type, v, tv);
}
TypeVariableSubstitutionVisitor sv(&tvs, true);
sv.setCalledBy(this);
auto cl = type->to<IR::Type>()->apply(sv);
CHECK_NULL(cl);
learn(cl, this);
LOG3("Cloned for type variables " << type << " into " << cl);
return cl->to<IR::Type>();
}
TypeInference::TypeInference(ReferenceMap *refMap, TypeMap *typeMap, bool readOnly,
bool checkArrays)
: refMap(refMap),
typeMap(typeMap),
initialNode(nullptr),
readOnly(readOnly),
checkArrays(checkArrays),
currentActionList(nullptr) {
CHECK_NULL(typeMap);
CHECK_NULL(refMap);
visitDagOnce = false; // the done() method will take care of this
}
Visitor::profile_t TypeInference::init_apply(const IR::Node *node) {
if (node->is<IR::P4Program>()) {
LOG3("Reference map for type checker:" << std::endl << refMap);
LOG2("TypeInference for " << dbp(node));
}
initialNode = node;
refMap->validateMap(node);
return Transform::init_apply(node);
}
void TypeInference::end_apply(const IR::Node *node) {
if (readOnly && !(*node == *initialNode)) {
BUG("At this point in the compilation typechecking "
"should not infer new types anymore, but it did.");
}
typeMap->updateMap(node);
if (node->is<IR::P4Program>()) LOG3("Typemap: " << std::endl << typeMap);
}
TypeInference *TypeInference::clone() const {
return new TypeInference(this->refMap, this->typeMap, true);
}
bool TypeInference::done() const {
auto orig = getOriginal();
bool done = typeMap->contains(orig);
LOG3("TI Visiting " << dbp(orig) << (done ? " done" : ""));
return done;
}
const IR::Type *TypeInference::getType(const IR::Node *element) const {
const IR::Type *result = typeMap->getType(element);
// This should be happening only when type-checking already failed
// for some node; we are now just trying to typecheck a parent node.
// So an error should have already been signalled.
if ((result == nullptr) && (::errorCount() == 0))
BUG("Could not find type of %1% %2%", dbp(element), element);
return result;
}
const IR::Type *TypeInference::getTypeType(const IR::Node *element) const {
const IR::Type *result = typeMap->getType(element);
// See comment in getType() above.
if (result == nullptr) {
if (::errorCount() == 0) BUG("Could not find type of %1%", element);
return nullptr;
}
BUG_CHECK(result->is<IR::Type_Type>(), "%1%: expected a TypeType", dbp(result));
return result->to<IR::Type_Type>()->type;
}
void TypeInference::setType(const IR::Node *element, const IR::Type *type) {
typeMap->setType(element, type);
}
void TypeInference::addSubstitutions(const TypeVariableSubstitution *tvs) {
typeMap->addSubstitutions(tvs);
}
TypeVariableSubstitution *TypeInference::unifyBase(
bool allowCasts, const IR::Node *errorPosition, const IR::Type *destType,
const IR::Type *srcType, cstring errorFormat,
std::initializer_list<const IR::Node *> errorArgs) {
CHECK_NULL(destType);
CHECK_NULL(srcType);
if (srcType == destType) return new TypeVariableSubstitution();
TypeConstraint *constraint;
TypeConstraints constraints(typeMap->getSubstitutions(), typeMap);
if (allowCasts)
constraint = new CanBeImplicitlyCastConstraint(destType, srcType, errorPosition);
else
constraint = new EqualityConstraint(destType, srcType, errorPosition);
if (!errorFormat.isNullOrEmpty()) constraint->setError(errorFormat, errorArgs);
constraints.add(constraint);
auto tvs = constraints.solve();
addSubstitutions(tvs);
return tvs;
}
const IR::Type *TypeInference::canonicalizeFields(
const IR::Type_StructLike *type,
std::function<const IR::Type *(const IR::IndexedVector<IR::StructField> *)> constructor) {
bool changes = false;
auto fields = new IR::IndexedVector<IR::StructField>();
for (auto field : type->fields) {
auto ftype = canonicalize(field->type);
if (ftype == nullptr) return nullptr;
if (ftype != field->type) changes = true;
BUG_CHECK(!ftype->is<IR::Type_Type>(), "%1%: TypeType in field type", ftype);
auto newField = new IR::StructField(field->srcInfo, field->name, field->annotations, ftype);
fields->push_back(newField);
}
if (changes)
return constructor(fields);
else
return type;
}
const IR::ParameterList *TypeInference::canonicalizeParameters(const IR::ParameterList *params) {
if (params == nullptr) return params;
bool changes = false;
auto vec = new IR::IndexedVector<IR::Parameter>();
for (auto p : *params->getEnumerator()) {
auto paramType = getTypeType(p->type);
if (paramType == nullptr) return nullptr;
BUG_CHECK(!paramType->is<IR::Type_Type>(), "%1%: Unexpected parameter type", paramType);
if (paramType != p->type) {
p = new IR::Parameter(p->srcInfo, p->name, p->annotations, p->direction, paramType,
p->defaultValue);
changes = true;
}
setType(p, paramType);
vec->push_back(p);
}
if (changes)
return new IR::ParameterList(params->srcInfo, *vec);
else
return params;
}
bool TypeInference::checkParameters(const IR::ParameterList *paramList, bool forbidModules,
bool forbidPackage) const {
for (auto p : paramList->parameters) {
auto type = getType(p);
if (type == nullptr) return false;
if (auto ts = type->to<IR::Type_SpecializedCanonical>()) type = ts->baseType;
if (forbidPackage && type->is<IR::Type_Package>()) {
typeError("%1%: parameter cannot be a package", p);
return false;
}
if (p->direction != IR::Direction::None &&
(type->is<IR::Type_Extern>() || type->is<IR::Type_String>())) {
typeError("%1%: a parameter with type %2% cannot have a direction", p, type);
return false;
}
if ((forbidModules || p->direction != IR::Direction::None) &&
(type->is<IR::Type_Parser>() || type->is<IR::Type_Control>() ||
type->is<IR::P4Parser>() || type->is<IR::P4Control>())) {
typeError("%1%: parameter cannot have type %2%", p, type);
return false;
}
}
return true;
}
/**
* Bind the parameters with the specified arguments.
* For example, given a type
* void _<T>(T data)
* it can be specialized to
* void _<int<32>>(int<32> data);
*/
const IR::Type *TypeInference::specialize(const IR::IMayBeGenericType *type,
const IR::Vector<IR::Type> *arguments) {
TypeVariableSubstitution *bindings = new TypeVariableSubstitution();
bool success = bindings->setBindings(type->getNode(), type->getTypeParameters(), arguments);
if (!success) return nullptr;
LOG2("Translation map\n" << bindings);
TypeVariableSubstitutionVisitor tsv(bindings);
const IR::Node *result = type->getNode()->apply(tsv);
if (result == nullptr) return nullptr;
LOG2("Specialized " << type << "\n\tinto " << result);
return result->to<IR::Type>();
}
// May return nullptr if a type error occurs.
const IR::Type *TypeInference::canonicalize(const IR::Type *type) {
if (type == nullptr) return nullptr;
auto exists = typeMap->getType(type);
if (exists != nullptr) {
if (exists->is<IR::Type_Type>()) return exists->to<IR::Type_Type>()->type;
return exists;
}
if (auto tt = type->to<IR::Type_Type>()) type = tt->type;
if (type->is<IR::Type_SpecializedCanonical>() || type->is<IR::Type_InfInt>() ||
type->is<IR::Type_Action>() || type->is<IR::Type_Error>() || type->is<IR::Type_Newtype>() ||
type->is<IR::Type_Table>()) {
return type;
} else if (type->is<IR::Type_Dontcare>()) {
return IR::Type_Dontcare::get();
} else if (type->is<IR::Type_Base>()) {
if (!type->is<IR::Type_Bits>())
// all other base types are singletons
return type;
auto tb = type->to<IR::Type_Bits>();
auto canon = IR::Type_Bits::get(tb->size, tb->isSigned);
if (!typeMap->contains(canon)) typeMap->setType(canon, new IR::Type_Type(canon));
return canon;
} else if (type->is<IR::Type_Enum>() || type->is<IR::Type_SerEnum>() ||
type->is<IR::Type_ActionEnum>() || type->is<IR::Type_MatchKind>()) {
return type;
} else if (auto set = type->to<IR::Type_Set>()) {
auto et = canonicalize(set->elementType);
if (et == nullptr) return nullptr;
if (et->is<IR::Type_Stack>() || et->is<IR::Type_Set>() || et->is<IR::Type_HeaderUnion>())
::error(ErrorType::ERR_TYPE_ERROR, "%1%: Sets of %2% are not supported", type, et);
if (et == set->elementType) return type;
const IR::Type *canon = new IR::Type_Set(type->srcInfo, et);
return canon;
} else if (auto stack = type->to<IR::Type_Stack>()) {
auto et = canonicalize(stack->elementType);
if (et == nullptr) return nullptr;
const IR::Type *canon;
if (et == stack->elementType)
canon = type;
else
canon = new IR::Type_Stack(stack->srcInfo, et, stack->size);
canon = typeMap->getCanonical(canon);
return canon;
} else if (auto vec = type->to<IR::Type_P4List>()) {
auto et = canonicalize(vec->elementType);
if (et == nullptr) return nullptr;
const IR::Type *canon;
if (et == vec->elementType)
canon = type;
else
canon = new IR::Type_P4List(vec->srcInfo, et);
canon = typeMap->getCanonical(canon);
return canon;
} else if (auto list = type->to<IR::Type_List>()) {
auto fields = new IR::Vector<IR::Type>();
// list<set<a>, b> = set<tuple<a, b>>
// TODO: this should not be done here.
bool anySet = false;
bool anyChange = false;
for (auto t : list->components) {
if (t->is<IR::Type_Set>()) {
anySet = true;
t = t->to<IR::Type_Set>()->elementType;
}
auto t1 = canonicalize(t);
anyChange = anyChange || t != t1;
if (t1 == nullptr) return nullptr;
fields->push_back(t1);
}
const IR::Type *canon;
if (anySet)
canon = new IR::Type_Tuple(type->srcInfo, *fields);
else if (anyChange)
canon = new IR::Type_List(type->srcInfo, *fields);
else
canon = type;
canon = typeMap->getCanonical(canon);
if (anySet) canon = new IR::Type_Set(type->srcInfo, canon);
return canon;
} else if (auto tuple = type->to<IR::Type_Tuple>()) {
auto fields = new IR::Vector<IR::Type>();
bool anyChange = false;
for (auto t : tuple->components) {
auto t1 = canonicalize(t);
anyChange = anyChange || t != t1;
if (t1 == nullptr) return nullptr;
fields->push_back(t1);
}
const IR::Type *canon;
if (anyChange)
canon = new IR::Type_Tuple(type->srcInfo, *fields);
else
canon = type;
canon = typeMap->getCanonical(canon);
return canon;
} else if (auto tp = type->to<IR::Type_Parser>()) {
auto pl = canonicalizeParameters(tp->applyParams);
auto tps = tp->typeParameters;
if (pl == nullptr || tps == nullptr) return nullptr;
if (!checkParameters(pl, forbidModules, forbidPackages)) return nullptr;
if (pl != tp->applyParams || tps != tp->typeParameters)
return new IR::Type_Parser(tp->srcInfo, tp->name, tp->annotations, tps, pl);
return type;
} else if (auto tp = type->to<IR::Type_Control>()) {
auto pl = canonicalizeParameters(tp->applyParams);
auto tps = tp->typeParameters;
if (pl == nullptr || tps == nullptr) return nullptr;
if (!checkParameters(pl, forbidModules, forbidPackages)) return nullptr;
if (pl != tp->applyParams || tps != tp->typeParameters)
return new IR::Type_Control(tp->srcInfo, tp->name, tp->annotations, tps, pl);
return type;
} else if (auto tp = type->to<IR::Type_Package>()) {
auto pl = canonicalizeParameters(tp->constructorParams);
auto tps = tp->typeParameters;
if (pl == nullptr || tps == nullptr) return nullptr;
if (pl != tp->constructorParams || tps != tp->typeParameters)
return new IR::Type_Package(tp->srcInfo, tp->name, tp->annotations, tps, pl);
return type;
} else if (auto cont = type->to<IR::P4Control>()) {
auto ctype0 = getTypeType(cont->type);
if (ctype0 == nullptr) return nullptr;
auto ctype = ctype0->to<IR::Type_Control>();
auto pl = canonicalizeParameters(cont->constructorParams);
if (pl == nullptr) return nullptr;
if (ctype != cont->type || pl != cont->constructorParams)
return new IR::P4Control(cont->srcInfo, cont->name, ctype, pl, cont->controlLocals,
cont->body);
return type;
} else if (auto p = type->to<IR::P4Parser>()) {
auto ctype0 = getTypeType(p->type);
if (ctype0 == nullptr) return nullptr;
auto ctype = ctype0->to<IR::Type_Parser>();
auto pl = canonicalizeParameters(p->constructorParams);
if (pl == nullptr) return nullptr;
if (ctype != p->type || pl != p->constructorParams)
return new IR::P4Parser(p->srcInfo, p->name, ctype, pl, p->parserLocals, p->states);
return type;
} else if (auto te = type->to<IR::Type_Extern>()) {
bool changes = false;
auto methods = new IR::Vector<IR::Method>();
for (auto method : te->methods) {
auto fpType = canonicalize(method->type);
if (fpType == nullptr) return nullptr;
if (fpType != method->type) {
method =
new IR::Method(method->srcInfo, method->name, fpType->to<IR::Type_Method>(),
method->isAbstract, method->annotations);
changes = true;
setType(method, fpType);
}
methods->push_back(method);
}
auto tps = te->typeParameters;
if (tps == nullptr) return nullptr;
const IR::Type *resultType = type;
if (changes || tps != te->typeParameters)
resultType = new IR::Type_Extern(te->srcInfo, te->name, tps, *methods);
return resultType;
} else if (auto mt = type->to<IR::Type_Method>()) {
const IR::Type *res = nullptr;
if (mt->returnType != nullptr) {
res = canonicalize(mt->returnType);
if (res == nullptr) return nullptr;
}
bool changes = res != mt->returnType;
auto pl = canonicalizeParameters(mt->parameters);
auto tps = mt->typeParameters;
if (pl == nullptr) return nullptr;
if (!checkParameters(pl)) return nullptr;
changes = changes || pl != mt->parameters || tps != mt->typeParameters;
const IR::Type *resultType = mt;
if (changes) resultType = new IR::Type_Method(mt->getSourceInfo(), tps, res, pl, mt->name);
return resultType;
} else if (auto hdr = type->to<IR::Type_Header>()) {
return canonicalizeFields(hdr, [hdr](const IR::IndexedVector<IR::StructField> *fields) {
return new IR::Type_Header(hdr->srcInfo, hdr->name, hdr->annotations,
hdr->typeParameters, *fields);
});
} else if (auto str = type->to<IR::Type_Struct>()) {
return canonicalizeFields(str, [str](const IR::IndexedVector<IR::StructField> *fields) {
return new IR::Type_Struct(str->srcInfo, str->name, str->annotations,
str->typeParameters, *fields);
});
} else if (auto hu = type->to<IR::Type_HeaderUnion>()) {
return canonicalizeFields(hu, [hu](const IR::IndexedVector<IR::StructField> *fields) {
return new IR::Type_HeaderUnion(hu->srcInfo, hu->name, hu->annotations,
hu->typeParameters, *fields);
});
} else if (auto su = type->to<IR::Type_UnknownStruct>()) {
return canonicalizeFields(su, [su](const IR::IndexedVector<IR::StructField> *fields) {
return new IR::Type_UnknownStruct(su->srcInfo, su->name, su->annotations, *fields);
});
} else if (auto st = type->to<IR::Type_Specialized>()) {
auto baseCanon = canonicalize(st->baseType);
if (baseCanon == nullptr) return nullptr;
if (st->arguments == nullptr) return baseCanon;
if (!baseCanon->is<IR::IMayBeGenericType>()) {
typeError(
"%1%: Type %2% is not generic and thus it"
" cannot be specialized using type arguments",
type, baseCanon);
return nullptr;
}
auto gt = baseCanon->to<IR::IMayBeGenericType>();
auto tp = gt->getTypeParameters();
if (tp->size() != st->arguments->size()) {
typeError("%1%: Type %2% has %3% type parameter(s), but it is specialized with %4%",
type, gt, tp->size(), st->arguments->size());
return nullptr;
}
IR::Vector<IR::Type> *args = new IR::Vector<IR::Type>();
for (const IR::Type *a : *st->arguments) {
auto atype = getTypeType(a);
if (atype == nullptr) return nullptr;
auto checkType = atype;
if (auto tsc = atype->to<IR::Type_SpecializedCanonical>()) checkType = tsc->baseType;
if (checkType->is<IR::Type_Control>() || checkType->is<IR::Type_Parser>() ||
checkType->is<IR::Type_Package>() || checkType->is<IR::P4Parser>() ||
checkType->is<IR::P4Control>()) {
typeError("%1%: Cannot use %2% as a type parameter", type, checkType);
return nullptr;
}
const IR::Type *canon = canonicalize(atype);
if (canon == nullptr) return nullptr;
args->push_back(canon);
}
auto specialized = specialize(gt, args);
auto result =
new IR::Type_SpecializedCanonical(type->srcInfo, baseCanon, args, specialized);
LOG2("Scanning the specialized type");
learn(result, this);
return result;
} else {
BUG_CHECK(::errorCount(), "Unexpected type %1%", dbp(type));
}
// If we reach this point some type error must have occurred, because
// the typeMap lookup at the beginning of the function has failed.
return nullptr;
}
///////////////////////////////////// Visitor methods
const IR::Node *TypeInference::preorder(IR::P4Program *program) {
currentActionList = nullptr;
if (typeMap->checkMap(getOriginal()) && readOnly) {
LOG2("No need to typecheck");
prune();
}
return program;
}
const IR::Node *TypeInference::postorder(IR::Type_Error *decl) {
(void)setTypeType(decl);
for (auto id : *decl->getDeclarations()) setType(id->getNode(), decl);
return decl;
}
const IR::Node *TypeInference::postorder(IR::Declaration_MatchKind *decl) {
if (done()) return decl;
for (auto id : *decl->getDeclarations()) setType(id->getNode(), IR::Type_MatchKind::get());
return decl;
}
const IR::Node *TypeInference::postorder(IR::Type_Table *type) {
(void)setTypeType(type);
return type;
}
const IR::Node *TypeInference::postorder(IR::P4Table *table) {
currentActionList = nullptr;
if (done()) return table;
auto type = new IR::Type_Table(table);
setType(getOriginal(), type);
setType(table, type);
return table;
}
const IR::Node *TypeInference::postorder(IR::P4Action *action) {
if (done()) return action;
auto pl = canonicalizeParameters(action->parameters);
if (pl == nullptr) return action;
if (!checkParameters(action->parameters, forbidModules, forbidPackages)) return action;
auto type = new IR::Type_Action(new IR::TypeParameters(), nullptr, pl);
bool foundDirectionless = false;
for (auto p : action->parameters->parameters) {
auto ptype = getType(p);
if (ptype->is<IR::Type_Extern>())
typeError("%1%: Action parameters cannot have extern types", p->type);
if (p->direction == IR::Direction::None)
foundDirectionless = true;
else if (foundDirectionless)
typeError("%1%: direction-less action parameters have to be at the end", p);
}
setType(getOriginal(), type);
setType(action, type);
return action;
}
const IR::Node *TypeInference::postorder(IR::Declaration_Variable *decl) {
if (done()) return decl;
auto type = getTypeType(decl->type);
if (type == nullptr) return decl;
if (type->is<IR::IMayBeGenericType>()) {
// Check that there are no unbound type parameters
const IR::IMayBeGenericType *gt = type->to<IR::IMayBeGenericType>();
if (!gt->getTypeParameters()->empty()) {
typeError("Unspecified type parameters for %1% in %2%", gt, decl);
return decl;
}
}
const IR::Type *baseType = type;
if (auto sc = type->to<IR::Type_SpecializedCanonical>()) baseType = sc->baseType;
if (baseType->is<IR::IContainer>() || baseType->is<IR::Type_Extern>() ||
baseType->is<IR::Type_Parser>() || baseType->is<IR::Type_Control>()) {
typeError("%1%: cannot declare variables of type '%2%' (consider using an instantiation)",
decl, type);
return decl;
}
if (type->is<IR::Type_String>() || type->is<IR::Type_InfInt>()) {
typeError("%1%: Cannot declare variables with type %2%", decl, type);
return decl;
}
auto orig = getOriginal<IR::Declaration_Variable>();
if (decl->initializer != nullptr) {
auto init = assignment(decl, type, decl->initializer);
if (decl->initializer != init) {
auto declType = type->getP4Type();
decl->type = declType;
decl->initializer = init;
LOG2("Created new declaration " << decl);
}
}
setType(decl, type);
setType(orig, type);
return decl;
}
bool TypeInference::canCastBetween(const IR::Type *dest, const IR::Type *src) const {
if (src->is<IR::Type_Action>()) return false;
if (src == dest) return true;
if (dest->is<IR::Type_Newtype>()) {
auto dt = getTypeType(dest->to<IR::Type_Newtype>()->type);
if (typeMap->equivalent(dt, src)) return true;
}
if (src->is<IR::Type_Bits>()) {
auto f = src->to<IR::Type_Bits>();
if (dest->is<IR::Type_Bits>()) {
auto t = dest->to<IR::Type_Bits>();
if (f->size == t->size)
return true;
else if (f->isSigned == t->isSigned)
return true;
} else if (dest->is<IR::Type_Boolean>()) {
return f->size == 1 && !f->isSigned;
} else if (auto de = dest->to<IR::Type_SerEnum>()) {
return typeMap->equivalent(src, getTypeType(de->type));
} else if (dest->is<IR::Type_InfInt>()) {
return true;
}
} else if (src->is<IR::Type_Boolean>()) {
if (dest->is<IR::Type_Bits>()) {
auto b = dest->to<IR::Type_Bits>();
return b->size == 1 && !b->isSigned;
}
} else if (src->is<IR::Type_InfInt>()) {
return dest->is<IR::Type_Bits>() || dest->is<IR::Type_Boolean>() ||
dest->is<IR::Type_InfInt>();
} else if (src->is<IR::Type_Newtype>()) {
auto st = getTypeType(src->to<IR::Type_Newtype>()->type);
return typeMap->equivalent(dest, st);
} else if (auto se = src->to<IR::Type_SerEnum>()) {
auto set = getTypeType(se->type);
if (auto db = dest->to<IR::Type_Bits>()) {
return typeMap->equivalent(set, db);
}
if (auto de = dest->to<IR::Type_SerEnum>()) {
return typeMap->equivalent(set, getTypeType(de->type));
}
}
return false;
}
const IR::Expression *TypeInference::assignment(const IR::Node *errorPosition,
const IR::Type *destType,
const IR::Expression *sourceExpression) {
if (destType->is<IR::Type_Unknown>()) BUG("Unknown destination type");
if (destType->is<IR::Type_Dontcare>()) return sourceExpression;
const IR::Type *initType = getType(sourceExpression);
if (initType == nullptr) return sourceExpression;
auto tvs = unifyCast(errorPosition, destType, initType,
"Source expression '%1%' produces a result of type '%2%' which cannot be "
"assigned to a left-value with type '%3%'",
{sourceExpression, initType, destType});
if (tvs == nullptr)
// error already signalled
return sourceExpression;
if (!tvs->isIdentity()) {
ConstantTypeSubstitution cts(tvs, refMap, typeMap, this);
sourceExpression = cts.convert(sourceExpression); // sets type
}
if (destType->is<IR::Type_SerEnum>() && !typeMap->equivalent(destType, initType)) {
typeError("%1%: values of type '%2%' cannot be implicitly cast to type '%3%'",
errorPosition, initType, destType);
return sourceExpression;
}
if (initType->is<IR::Type_InfInt>() && !destType->is<IR::Type_InfInt>()) {
auto toType = destType->getP4Type();
sourceExpression = new IR::Cast(toType, sourceExpression);
setType(toType, new IR::Type_Type(destType));
setType(sourceExpression, destType);
setCompileTimeConstant(sourceExpression);
}
auto concreteType = destType;
if (auto tsc = destType->to<IR::Type_SpecializedCanonical>()) concreteType = tsc->substituted;
bool cst = isCompileTimeConstant(sourceExpression);
if (auto ts = concreteType->to<IR::Type_StructLike>()) {
auto si = sourceExpression->to<IR::StructExpression>();
auto type = destType->getP4Type();
setType(type, new IR::Type_Type(destType));
if (initType->is<IR::Type_UnknownStruct>() ||
(si != nullptr && initType->is<IR::Type_Struct>())) {
// Even if the structure is a struct expression with the right type,
// we still need to recurse over its fields; they many not have
// the right type.
CHECK_NULL(si);
if (ts->fields.size() != si->components.size()) {
typeError("%1%: destination type expects %2% fields, but source only has %3%",
errorPosition, ts->fields.size(), si->components.size());
return sourceExpression;
}
IR::IndexedVector<IR::NamedExpression> vec;
bool changes = false;
for (size_t i = 0; i < ts->fields.size(); i++) {
auto fieldI = ts->fields.at(i);
auto compI = si->components.at(i)->expression;
auto src = assignment(sourceExpression, fieldI->type, compI);
if (src != compI) changes = true;
vec.push_back(new IR::NamedExpression(fieldI->name, src));
}
if (!changes) vec = si->components;
if (initType->is<IR::Type_UnknownStruct>() || changes) {
sourceExpression = new IR::StructExpression(type, type, vec);
setType(sourceExpression, destType);
}
} else if (auto li = sourceExpression->to<IR::ListExpression>()) {
if (ts->fields.size() != li->components.size()) {
typeError("%1%: destination type expects %2% fields, but source only has %3%",
errorPosition, ts->fields.size(), li->components.size());
return sourceExpression;
}
IR::IndexedVector<IR::NamedExpression> vec;
for (size_t i = 0; i < ts->fields.size(); i++) {
auto fieldI = ts->fields.at(i);
auto compI = li->components.at(i);
auto src = assignment(sourceExpression, fieldI->type, compI);
vec.push_back(new IR::NamedExpression(fieldI->name, src));
}
sourceExpression = new IR::StructExpression(type, type, vec);
setType(sourceExpression, destType);
}
// else this is some other expression that evaluates to a struct
if (cst) setCompileTimeConstant(sourceExpression);
} else if (auto tt = concreteType->to<IR::Type_Tuple>()) {
if (auto li = sourceExpression->to<IR::ListExpression>()) {
if (tt->getSize() != li->components.size()) {
typeError("%1%: destination type expects %2% fields, but source only has %3%",
errorPosition, tt->getSize(), li->components.size());
return sourceExpression;
}
bool changed = false;
IR::Vector<IR::Expression> vec;
for (size_t i = 0; i < tt->getSize(); i++) {
auto typeI = tt->at(i);
auto compI = li->components.at(i);
auto src = assignment(sourceExpression, typeI, compI);
if (src != compI) changed = true;
vec.push_back(src);
}
if (changed) sourceExpression = new IR::ListExpression(vec);
}
// else this is some other expression that evaluates to a tuple
setType(sourceExpression, destType);
if (cst) setCompileTimeConstant(sourceExpression);
}
return sourceExpression;
}
const IR::Node *TypeInference::postorder(IR::Annotation *annotation) {
auto checkAnnotation = [this](const IR::Expression *e) {
if (!isCompileTimeConstant(e))
typeError("%1%: structured annotation must be compile-time constant values", e);
auto t = getType(e);
if (!t)
// type error during typechecking
return;
if (!t->is<IR::Type_InfInt>() && !t->is<IR::Type_String>() && !t->is<IR::Type_Boolean>())
typeError("%1%: illegal type for structured annotation; must be int, string or bool",
e);
};
if (annotation->structured) {
// If it happens here it was created in the compiler, so it's a bug, not an error.
BUG_CHECK(annotation->expr.empty() || annotation->kv.empty(),
"%1%: structured annotations cannot contain expressions and kv-pairs",
annotation);
for (auto e : annotation->expr) checkAnnotation(e);
for (auto e : annotation->kv) checkAnnotation(e->expression);
}
return annotation;
}
const IR::Node *TypeInference::postorder(IR::Declaration_Constant *decl) {
if (done()) return decl;
auto type = getTypeType(decl->type);
if (type == nullptr) return decl;
if (type->is<IR::Type_Extern>()) {
typeError("%1%: Cannot declare constants of extern types", decl->name);
return decl;
}
if (!isCompileTimeConstant(decl->initializer))
typeError("%1%: Cannot evaluate initializer to a compile-time constant", decl->initializer);
auto orig = getOriginal<IR::Declaration_Constant>();
auto newInit = assignment(decl, type, decl->initializer);
if (newInit != decl->initializer)
decl = new IR::Declaration_Constant(decl->srcInfo, decl->name, decl->annotations,
decl->type, newInit);
setType(decl, type);
setType(orig, type);
return decl;
}
// Returns the type of the constructed object and
// new arguments for constructor, which may have inserted casts.
std::pair<const IR::Type *, const IR::Vector<IR::Argument> *> TypeInference::checkExternConstructor(
const IR::Node *errorPosition, const IR::Type_Extern *ext,
const IR::Vector<IR::Argument> *arguments) {
auto none = std::pair<const IR::Type *, const IR::Vector<IR::Argument> *>(nullptr, nullptr);
auto freshExtern = cloneWithFreshTypeVariables(ext)->to<IR::Type_Extern>();
auto constructor = freshExtern->lookupConstructor(arguments);
if (constructor == nullptr) {
typeError("%1%: type %2% has no matching constructor", errorPosition, ext);
return none;
}
auto mt = getType(constructor);
if (mt == nullptr) return none;
auto methodType = mt->to<IR::Type_Method>();
BUG_CHECK(methodType != nullptr, "Constructor does not have a method type, but %1%", mt);
if (errorPosition->is<IR::ConstructorCallExpression>()) {
for (auto m : ext->methods) {
if (m->isAbstract) {
typeError(
"%1%: extern type %2% with abstract methods cannot be instantiated"
" using a constructor call; consider using a declaration",
errorPosition, ext);
return none;
}
}
}
auto args = new IR::Vector<IR::ArgumentInfo>();
size_t i = 0;
for (auto pi : *methodType->parameters->getEnumerator()) {
if (i >= arguments->size()) {
BUG_CHECK(pi->isOptional() || pi->defaultValue != nullptr, "Missing nonoptional arg %s",
pi);
break;
}
auto arg = arguments->at(i++);
if (!isCompileTimeConstant(arg->expression))
typeError("%1%: cannot evaluate to a compile-time constant", arg);
auto argType = getType(arg->expression);
auto paramType = getType(pi);
if (argType == nullptr || paramType == nullptr) return none;
if (paramType->is<IR::Type_Control>() || paramType->is<IR::Type_Parser>() ||
paramType->is<IR::P4Control>() || paramType->is<IR::P4Parser>() ||
paramType->is<IR::Type_Package>())
typeError("%1%: parameter cannot have type %2%", pi, paramType);
auto argInfo = new IR::ArgumentInfo(arg->srcInfo, arg->expression, true, argType, arg);
args->push_back(argInfo);
}
// will always be bound to Type_Void.
auto rettype = new IR::Type_Var(IR::ID(refMap->newName("R"), "<returned type>"));
auto callType =
new IR::Type_MethodCall(errorPosition->srcInfo, new IR::Vector<IR::Type>(), rettype, args);
auto tvs = unify(errorPosition, methodType, callType,
"Constructor invocation %1% does not match constructor declaration %2%",
{callType, constructor});
BUG_CHECK(tvs != nullptr || ::errorCount(), "Unification failed with no error");
if (tvs == nullptr) return none;
LOG2("Constructor type before specialization " << methodType << " with " << tvs);
TypeVariableSubstitutionVisitor substVisitor(tvs);
substVisitor.setCalledBy(this);
auto specMethodType = methodType->apply(substVisitor);
LOG2("Constructor type after specialization " << specMethodType);
learn(specMethodType, this);
auto canon = getType(specMethodType);
if (canon == nullptr) return none;
auto functionType = specMethodType->to<IR::Type_MethodBase>();
BUG_CHECK(functionType != nullptr, "Method type is %1%", specMethodType);
if (!functionType->is<IR::Type_Method>()) BUG("Unexpected type for function %1%", functionType);
ConstantTypeSubstitution cts(tvs, refMap, typeMap, this);
// Arguments may need to be cast, e.g., list expression to a
// header type.
auto paramIt = functionType->parameters->begin();
auto newArgs = new IR::Vector<IR::Argument>();
bool changed = false;
for (auto arg : *arguments) {
cstring argName = arg->name.name;
bool named = !argName.isNullOrEmpty();
const IR::Parameter *param;
if (named) {
param = functionType->parameters->getParameter(argName);
} else {
BUG_CHECK(paramIt != functionType->parameters->end(), "Not enough parameters %1%",
errorPosition);
param = *paramIt;
}
auto newExpr = arg->expression;
if (param->direction == IR::Direction::In || param->direction == IR::Direction::None) {
// This is like an assignment; may make additional conversions.
newExpr = assignment(arg, param->type, arg->expression);
} else {
// Insert casts for 'int' values.
newExpr = cts.convert(newExpr)->to<IR::Expression>();
}
if (::errorCount() > 0) return none;
if (newExpr != arg->expression) {
LOG2("Changing method argument to " << newExpr);
changed = true;
newArgs->push_back(new IR::Argument(arg->srcInfo, arg->name, newExpr));
} else {
newArgs->push_back(arg);