zeek/tools/binpac/src/pac_expr.cc

861 lines
25 KiB
C++

// See the file "COPYING" in the main distribution directory for copyright.
#include "pac_expr.h"
#include "pac_case.h"
#include "pac_cstr.h"
#include "pac_exception.h"
#include "pac_exttype.h"
#include "pac_id.h"
#include "pac_let.h"
#include "pac_nullptr.h"
#include "pac_number.h"
#include "pac_output.h"
#include "pac_record.h"
#include "pac_regex.h"
#include "pac_typedecl.h"
#include "pac_utils.h"
string OrigExprList(ExprList* list) {
bool first = true;
string str;
foreach (i, ExprList, list) {
Expr* expr = *i;
if ( first )
first = false;
else
str += ", ";
str += expr->orig();
}
return str;
}
string EvalExprList(ExprList* exprlist, Output* out, Env* env) {
string val_list("");
bool first = true;
foreach (i, ExprList, exprlist) {
if ( ! first )
val_list += ", ";
val_list += (*i)->EvalExpr(out, env);
first = false;
}
return val_list;
}
static const char* expr_fmt[] = {
// NOLINTNEXTLINE(cppcoreguidelines-macro-usage)
#define EXPR_DEF(type, num_op, fmt) fmt,
#include "pac_expr.def"
#undef EXPR_DEF
};
void Expr::init() {
id_ = nullptr;
num_ = nullptr;
cstr_ = nullptr;
regex_ = nullptr;
num_operands_ = 0;
operand_[0] = nullptr;
operand_[1] = nullptr;
operand_[2] = nullptr;
args_ = nullptr;
cases_ = nullptr;
}
Expr::Expr(ID* arg_id) : DataDepElement(EXPR) {
init();
expr_type_ = EXPR_ID;
id_ = arg_id;
orig_ = strfmt("%s", id_->Name());
}
Expr::Expr(Number* arg_num) : DataDepElement(EXPR) {
init();
expr_type_ = EXPR_NUM;
num_ = arg_num;
orig_ = strfmt("((int) %s)", num_->Str());
}
Expr::Expr(Nullptr* arg_nullp) : DataDepElement(EXPR) {
init();
expr_type_ = EXPR_NULLPTR;
nullp_ = arg_nullp;
orig_ = strfmt("%s", nullp_->Str());
}
Expr::Expr(ConstString* cstr) : DataDepElement(EXPR) {
init();
expr_type_ = EXPR_CSTR;
cstr_ = cstr;
orig_ = cstr_->str();
}
Expr::Expr(RegEx* regex) : DataDepElement(EXPR) {
init();
expr_type_ = EXPR_REGEX;
regex_ = regex;
orig_ = strfmt("/%s/", regex_->str().c_str());
}
Expr::Expr(ExprType arg_type, Expr* op1) : DataDepElement(EXPR) {
init();
expr_type_ = arg_type;
num_operands_ = 1;
operand_[0] = op1;
orig_ = strfmt(expr_fmt[expr_type_], op1->orig());
}
Expr::Expr(ExprType arg_type, Expr* op1, Expr* op2) : DataDepElement(EXPR) {
init();
expr_type_ = arg_type;
num_operands_ = 2;
operand_[0] = op1;
operand_[1] = op2;
operand_[2] = nullptr;
orig_ = strfmt(expr_fmt[expr_type_], op1->orig(), op2->orig());
}
Expr::Expr(ExprType arg_type, Expr* op1, Expr* op2, Expr* op3) : DataDepElement(EXPR) {
init();
expr_type_ = arg_type;
num_operands_ = 3;
operand_[0] = op1;
operand_[1] = op2;
operand_[2] = op3;
orig_ = strfmt(expr_fmt[expr_type_], op1->orig(), op2->orig(), op3->orig());
}
Expr::Expr(ExprList* args) : DataDepElement(EXPR) {
init();
expr_type_ = EXPR_CALLARGS;
num_operands_ = -1;
args_ = args;
orig_ = OrigExprList(args_);
}
Expr::Expr(Expr* index, CaseExprList* cases) : DataDepElement(EXPR) {
init();
expr_type_ = EXPR_CASE;
num_operands_ = -1;
operand_[0] = index;
cases_ = cases;
orig_ = strfmt("case %s of { ", index->orig());
foreach (i, CaseExprList, cases_) {
CaseExpr* c = *i;
orig_ += strfmt("%s => %s; ", OrigExprList(c->index()).c_str(), c->value()->orig());
}
orig_ += "}";
}
Expr::~Expr() {
delete id_;
delete operand_[0];
delete operand_[1];
delete operand_[2];
delete_list(args_);
delete_list(cases_);
}
void Expr::AddCaseExpr(CaseExpr* case_expr) {
ASSERT(str_.empty());
ASSERT(expr_type_ == EXPR_CASE);
ASSERT(cases_);
cases_->push_back(case_expr);
}
void Expr::GenStrFromFormat(Env* env) {
// The format != "@custom@"
ASSERT(*expr_fmt[expr_type_] != '@');
switch ( num_operands_ ) {
case 1: str_ = strfmt(expr_fmt[expr_type_], operand_[0]->str()); break;
case 2: str_ = strfmt(expr_fmt[expr_type_], operand_[0]->str(), operand_[1]->str()); break;
case 3: str_ = strfmt(expr_fmt[expr_type_], operand_[0]->str(), operand_[1]->str(), operand_[2]->str()); break;
default:
DEBUG_MSG("num_operands_ = %d, orig = %s\n", num_operands_, orig());
ASSERT(0);
break;
}
}
namespace {
RecordField* GetRecordField(const ID* id, Env* env) {
Field* field = env->GetField(id);
ASSERT(field);
if ( field->tof() != RECORD_FIELD && field->tof() != PADDING_FIELD )
throw Exception(id, "not a record field");
RecordField* r = static_cast<RecordField*>(field);
ASSERT(r);
return r;
}
} // namespace
void Expr::GenCaseEval(Output* out_cc, Env* env) {
ASSERT(expr_type_ == EXPR_CASE);
ASSERT(operand_[0]);
ASSERT(cases_);
Type* val_type = DataType(env);
ID* val_var = env->AddTempID(val_type);
// DataType(env) can return a null pointer if an enum value is not
// defined.
if ( ! val_type )
throw Exception(this, "undefined case value");
out_cc->println("%s %s;", val_type->DataTypeStr().c_str(), env->LValue(val_var));
// force evaluation of IDs appearing in case stmt
operand_[0]->ForceIDEval(out_cc, env);
foreach (i, CaseExprList, cases_)
(*i)->value()->ForceIDEval(out_cc, env);
out_cc->println("// NOLINTBEGIN(bugprone-branch-clone)");
out_cc->println("switch ( %s ) {", operand_[0]->EvalExpr(out_cc, env));
Type* switch_type = operand_[0]->DataType(env);
out_cc->inc_indent();
CaseExpr* default_case = nullptr;
foreach (i, CaseExprList, cases_) {
CaseExpr* c = *i;
ExprList* index = c->index();
if ( ! index ) {
if ( default_case )
throw Exception(c, "duplicate default cases");
default_case = c;
}
else {
GenCaseStr(index, out_cc, env, switch_type);
out_cc->inc_indent();
out_cc->println("%s = %s;", env->LValue(val_var), c->value()->EvalExpr(out_cc, env));
out_cc->println("break;");
out_cc->dec_indent();
}
}
// Generate the default case after all other cases
GenCaseStr(nullptr, out_cc, env, switch_type);
out_cc->inc_indent();
if ( default_case ) {
out_cc->println("%s = %s;", env->LValue(val_var), default_case->value()->EvalExpr(out_cc, env));
}
else {
out_cc->println("throw binpac::ExceptionInvalidCaseIndex(\"%s\", (int64)%s);", Location(),
operand_[0]->EvalExpr(out_cc, env));
}
out_cc->println("break;");
out_cc->dec_indent();
out_cc->dec_indent();
out_cc->println("}");
out_cc->println("// NOLINTEND(bugprone-branch-clone)");
env->SetEvaluated(val_var);
str_ = env->RValue(val_var);
}
void Expr::GenEval(Output* out_cc, Env* env) {
switch ( expr_type_ ) {
case EXPR_NUM: str_ = num_->Str(); break;
case EXPR_NULLPTR: str_ = nullp_->Str(); break;
case EXPR_ID:
if ( ! env->Evaluated(id_) )
env->Evaluate(out_cc, id_);
str_ = env->RValue(id_);
break;
case EXPR_MEMBER: {
/*
For member expressions such X.Y, evaluating
X only is sufficient. (Actually trying to
evaluate Y will lead to error because Y is
not defined in the current environment.)
*/
operand_[0]->GenEval(out_cc, env);
Type* ty0 = operand_[0]->DataType(env);
if ( ty0 ) {
str_ = strfmt("%s%s", operand_[0]->EvalExpr(out_cc, env), ty0->EvalMember(operand_[1]->id()).c_str());
}
else {
string tmp = strfmt("->%s()", operand_[1]->id()->Name());
str_ = strfmt("%s%s", operand_[0]->EvalExpr(out_cc, env), tmp.c_str());
}
} break;
case EXPR_SUBSCRIPT: {
operand_[0]->GenEval(out_cc, env);
operand_[1]->GenEval(out_cc, env);
string v0 = operand_[0]->EvalExpr(out_cc, env);
string v1 = operand_[1]->EvalExpr(out_cc, env);
Type* ty0 = operand_[0]->DataType(env);
if ( ty0 )
str_ = ty0->EvalElement(v0, v1);
else
str_ = strfmt("%s[%s]", v0.c_str(), v1.c_str());
} break;
case EXPR_SIZEOF: {
const ID* id = operand_[0]->id();
RecordField* rf;
Type* ty;
try {
if ( rf = GetRecordField(id, env); rf != nullptr ) {
str_ = strfmt("%s", rf->FieldSize(out_cc, env));
}
} catch ( ExceptionIDNotFound& e ) {
if ( ty = TypeDecl::LookUpType(id); ty != nullptr ) {
int ty_size = ty->StaticSize(global_env());
if ( ty_size >= 0 )
str_ = strfmt("%d", ty_size);
else
throw Exception(id, "unknown size");
}
else
throw Exception(id, "not a record field or type");
}
} break;
case EXPR_OFFSETOF: {
const ID* id = operand_[0]->id();
RecordField* rf = GetRecordField(id, env);
str_ = strfmt("%s", rf->FieldOffset(out_cc, env));
} break;
case EXPR_CALLARGS: str_ = EvalExprList(args_, out_cc, env); break;
case EXPR_CASE: GenCaseEval(out_cc, env); break;
default:
// Evaluate every operand by default
for ( auto& op : operand_ )
if ( op )
op->GenEval(out_cc, env);
GenStrFromFormat(env);
break;
}
}
void Expr::ForceIDEval(Output* out_cc, Env* env) {
switch ( expr_type_ ) {
case EXPR_NUM:
case EXPR_SIZEOF:
case EXPR_OFFSETOF: break;
case EXPR_ID:
if ( ! env->Evaluated(id_) )
env->Evaluate(out_cc, id_);
break;
case EXPR_MEMBER: operand_[0]->ForceIDEval(out_cc, env); break;
case EXPR_CALLARGS: {
foreach (i, ExprList, args_)
(*i)->ForceIDEval(out_cc, env);
} break;
case EXPR_CASE: {
operand_[0]->ForceIDEval(out_cc, env);
foreach (i, CaseExprList, cases_)
(*i)->value()->ForceIDEval(out_cc, env);
} break;
default:
// Evaluate every operand by default
for ( auto& op : operand_ )
if ( op )
op->ForceIDEval(out_cc, env);
break;
}
}
const char* Expr::EvalExpr(Output* out_cc, Env* env) {
GenEval(out_cc, env);
return str();
}
Type* Expr::DataType(Env* env) const {
Type* data_type;
switch ( expr_type_ ) {
case EXPR_ID: data_type = env->GetDataType(id_); break;
case EXPR_MEMBER: {
// Get type of the parent
Type* parent_type = operand_[0]->DataType(env);
if ( ! parent_type )
return nullptr;
data_type = parent_type->MemberDataType(operand_[1]->id());
} break;
case EXPR_SUBSCRIPT: {
// Get type of the parent
Type* parent_type = operand_[0]->DataType(env);
data_type = parent_type->ElementDataType();
} break;
case EXPR_PAREN: data_type = operand_[0]->DataType(env); break;
case EXPR_COND: {
Type* type1 = operand_[1]->DataType(env);
Type* type2 = operand_[2]->DataType(env);
if ( ! Type::CompatibleTypes(type1, type2) ) {
throw Exception(this, strfmt("type mismatch: %s vs %s", type1->DataTypeStr().c_str(),
type2->DataTypeStr().c_str()));
}
data_type = type1;
} break;
case EXPR_CALL: data_type = operand_[0]->DataType(env); break;
case EXPR_CASE: {
if ( cases_ && ! cases_->empty() ) {
Type* type1 = cases_->front()->value()->DataType(env);
Type* numeric_with_largest_width = nullptr;
foreach (i, CaseExprList, cases_) {
Type* type2 = (*i)->value()->DataType(env);
if ( ! Type::CompatibleTypes(type1, type2) ) {
throw Exception(this, strfmt("type mismatch: %s vs %s", type1->DataTypeStr().c_str(),
type2->DataTypeStr().c_str()));
}
if ( type1 == extern_type_nullptr )
type1 = type2;
if ( type2 && type2->IsNumericType() ) {
if ( numeric_with_largest_width ) {
int largest;
int contender;
// External C++ types like "int", "bool", "enum" use "int"
// storage internally.
if ( numeric_with_largest_width->tot() == Type::EXTERN )
largest = sizeof(int);
else
largest = numeric_with_largest_width->StaticSize(env);
if ( type2->tot() == Type::EXTERN )
contender = sizeof(int);
else
contender = type2->StaticSize(env);
if ( contender > largest )
numeric_with_largest_width = type2;
}
else
numeric_with_largest_width = type2;
}
}
data_type = numeric_with_largest_width ? numeric_with_largest_width : type1;
}
else
data_type = nullptr;
} break;
case EXPR_NUM:
case EXPR_SIZEOF:
case EXPR_OFFSETOF:
case EXPR_NEG:
case EXPR_PLUS:
case EXPR_MINUS:
case EXPR_TIMES:
case EXPR_DIV:
case EXPR_MOD:
case EXPR_BITNOT:
case EXPR_BITAND:
case EXPR_BITOR:
case EXPR_BITXOR:
case EXPR_LSHIFT:
case EXPR_RSHIFT:
case EXPR_EQUAL:
case EXPR_GE:
case EXPR_LE:
case EXPR_GT:
case EXPR_LT:
case EXPR_NOT:
case EXPR_AND:
case EXPR_OR: data_type = extern_type_int; break;
default: data_type = nullptr; break;
}
return data_type;
}
string Expr::DataTypeStr(Env* env) const {
Type* type = DataType(env);
if ( ! type ) {
throw Exception(this, strfmt("cannot find data type for expression `%s'", orig()));
}
return type->DataTypeStr();
}
string Expr::SetFunc(Output* out, Env* env) {
switch ( expr_type_ ) {
case EXPR_ID: return set_function(id_);
case EXPR_MEMBER: {
// Evaluate the parent
string parent_val(operand_[0]->EvalExpr(out, env));
return parent_val + "->" + set_function(operand_[1]->id());
} break;
default:
throw Exception(this, strfmt("cannot generate set function "
"for expression `%s'",
orig()));
break;
}
}
bool Expr::ConstFold(Env* env, int* pn) const {
switch ( expr_type_ ) {
case EXPR_NUM: *pn = num_->Num(); return true;
case EXPR_ID: return env->GetConstant(id_, pn);
default:
// ### FIXME: folding consts
return false;
}
}
// TODO: build a generic data dependency extraction process
namespace {
// Maximum of two minimal header sizes
int mhs_max(int h1, int h2) {
if ( h1 < 0 || h2 < 0 )
return -1;
else {
// return max(h1, h2);
return h1 > h2 ? h1 : h2;
}
}
// MHS required to evaluate the field
int mhs_letfield(Env* env, LetField* field) { return field->expr()->MinimalHeaderSize(env); }
int mhs_recordfield(Env* env, RecordField* field) {
int offset = field->static_offset();
if ( offset < 0 ) // offset cannot be statically determined
return -1;
int size = field->StaticSize(env, offset);
if ( size < 0 ) // size cannot be statically determined
return -1;
return offset + size;
}
int mhs_casefield(Env* env, CaseField* field) {
// TODO: deal with the index
int size = field->StaticSize(env);
if ( size < 0 ) // size cannot be statically determined
return -1;
return size;
}
int mhs_field(Env* env, Field* field) {
int mhs = -1;
switch ( field->tof() ) {
case LET_FIELD: {
LetField* f = static_cast<LetField*>(field);
ASSERT(f);
mhs = mhs_letfield(env, f);
} break;
case CONTEXT_FIELD:
case FLOW_FIELD: ASSERT(0); break;
case PARAM_FIELD: mhs = 0; break;
case RECORD_FIELD:
case PADDING_FIELD: {
RecordField* f = static_cast<RecordField*>(field);
ASSERT(f);
mhs = mhs_recordfield(env, f);
} break;
case CASE_FIELD: {
CaseField* f = static_cast<CaseField*>(field);
ASSERT(f);
mhs = mhs_casefield(env, f);
} break;
case PARSE_VAR_FIELD:
case PRIV_VAR_FIELD:
case PUB_VAR_FIELD:
case TEMP_VAR_FIELD: mhs = 0; break;
case WITHINPUT_FIELD: {
// ### TODO: fix this
mhs = -1;
} break;
}
return mhs;
}
int mhs_id(Env* env, const ID* id) {
int mhs = -1;
switch ( env->GetIDType(id) ) {
case CONST:
case GLOBAL_VAR:
case TEMP_VAR:
case STATE_VAR:
case FUNC_ID:
case FUNC_PARAM: mhs = 0; break;
case MEMBER_VAR:
case PRIV_MEMBER_VAR: {
Field* field = env->GetField(id);
if ( ! field )
throw ExceptionIDNotField(id);
mhs = mhs_field(env, field);
} break;
case UNION_VAR:
// TODO: deal with UNION_VAR
mhs = -1;
break;
case MACRO: {
Expr* e = env->GetMacro(id);
mhs = e->MinimalHeaderSize(env);
} break;
}
return mhs;
}
} // namespace
int Expr::MinimalHeaderSize(Env* env) {
int mhs;
switch ( expr_type_ ) {
case EXPR_NUM:
// Zero byte is required
mhs = 0;
break;
case EXPR_ID: mhs = mhs_id(env, id_); break;
case EXPR_MEMBER:
// TODO: this is not a tight bound because
// one actually does not have to parse the
// whole record to compute one particular
// field.
mhs = operand_[0]->MinimalHeaderSize(env);
break;
case EXPR_SUBSCRIPT: {
int index;
Type* array_type = operand_[0]->DataType(env);
Type* elem_type = array_type->ElementDataType();
int elem_size = elem_type->StaticSize(env);
if ( elem_size >= 0 && operand_[1]->ConstFold(env, &index) ) {
mhs = elem_size * index;
}
else {
mhs = -1;
}
} break;
case EXPR_SIZEOF: {
const ID* id = operand_[0]->id();
ASSERT(id);
RecordField* rf;
Type* ty;
if ( rf = GetRecordField(id, env); rf != nullptr ) {
if ( rf->StaticSize(env, -1) >= 0 )
mhs = 0;
else
mhs = mhs_recordfield(env, rf);
}
else if ( ty = TypeDecl::LookUpType(id); ty != nullptr ) {
mhs = 0;
}
else
throw Exception(id, "not a record field or type");
} break;
case EXPR_OFFSETOF: {
const ID* id = operand_[0]->id();
ASSERT(id);
RecordField* field = GetRecordField(id, env);
mhs = field->static_offset();
if ( mhs < 0 ) {
mhs = 0;
// Take the MHS of the preceding (non-let) field
RecordField* prev_field = field->prev();
ASSERT(prev_field);
mhs = mhs_recordfield(env, prev_field);
}
} break;
case EXPR_CALLARGS: {
mhs = 0;
if ( args_ )
for ( const auto& arg : *args_ )
mhs = mhs_max(mhs, arg->MinimalHeaderSize(env));
} break;
case EXPR_CASE: {
mhs = operand_[0]->MinimalHeaderSize(env);
for ( const auto& ce : *cases_ ) {
if ( ce->index() )
for ( const auto& idx : *(ce->index()) )
mhs = mhs_max(mhs, idx->MinimalHeaderSize(env));
mhs = mhs_max(mhs, ce->value()->MinimalHeaderSize(env));
}
} break;
default:
// Evaluate every operand by default
mhs = 0;
for ( auto& op : operand_ )
if ( op )
mhs = mhs_max(mhs, op->MinimalHeaderSize(env));
break;
}
return mhs;
}
bool Expr::HasReference(const ID* id) const {
switch ( expr_type_ ) {
case EXPR_ID: return *id == *id_;
case EXPR_MEMBER: return operand_[0]->HasReference(id);
case EXPR_CALLARGS: {
foreach (i, ExprList, args_)
if ( (*i)->HasReference(id) )
return true;
}
return false;
case EXPR_CASE: {
foreach (i, CaseExprList, cases_)
if ( (*i)->HasReference(id) )
return true;
}
return false;
default:
// Evaluate every operand by default
for ( auto& op : operand_ ) {
if ( op && op->HasReference(id) ) {
return true;
}
}
return false;
}
}
bool Expr::DoTraverse(DataDepVisitor* visitor) {
switch ( expr_type_ ) {
case EXPR_ID: break;
case EXPR_MEMBER:
/*
For member expressions such X.Y, evaluating
X only is sufficient. (Actually trying to
evaluate Y will lead to error because Y is
not defined in the current environment.)
*/
if ( ! operand_[0]->Traverse(visitor) )
return false;
break;
case EXPR_CALLARGS: {
foreach (i, ExprList, args_)
if ( ! (*i)->Traverse(visitor) )
return false;
} break;
case EXPR_CASE: {
foreach (i, CaseExprList, cases_)
if ( ! (*i)->Traverse(visitor) )
return false;
} break;
default:
// Evaluate every operand by default
for ( auto& op : operand_ ) {
if ( op && ! op->Traverse(visitor) ) {
return false;
}
}
break;
}
return true;
}
bool Expr::RequiresAnalyzerContext() const {
switch ( expr_type_ ) {
case EXPR_ID: return *id_ == *analyzer_context_id;
case EXPR_MEMBER:
/*
For member expressions such X.Y, evaluating
X only is sufficient. (Actually trying to
evaluate Y will lead to error because Y is
not defined in the current environment.)
*/
return operand_[0]->RequiresAnalyzerContext();
case EXPR_CALLARGS: {
foreach (i, ExprList, args_)
if ( (*i)->RequiresAnalyzerContext() )
return true;
}
return false;
case EXPR_CASE: {
foreach (i, CaseExprList, cases_)
if ( (*i)->RequiresAnalyzerContext() )
return true;
}
return false;
default:
// Evaluate every operand by default
for ( auto& op : operand_ )
if ( op && op->RequiresAnalyzerContext() ) {
DEBUG_MSG("'%s' requires analyzer context\n", op->orig());
return true;
}
return false;
}
}
CaseExpr::CaseExpr(ExprList* index, Expr* value)
: DataDepElement(DataDepElement::CASEEXPR), index_(index), value_(value) {}
CaseExpr::~CaseExpr() {
delete_list(index_);
index_ = nullptr;
delete value_;
}
bool CaseExpr::DoTraverse(DataDepVisitor* visitor) {
foreach (i, ExprList, index_)
if ( ! (*i)->Traverse(visitor) )
return false;
return value_->Traverse(visitor);
}
bool CaseExpr::HasReference(const ID* id) const { return value_->HasReference(id); }
bool CaseExpr::RequiresAnalyzerContext() const {
// index_ should evaluate to constants
return value_->RequiresAnalyzerContext();
}