mirror of
https://github.com/privatevoid-net/nix-super.git
synced 2024-11-11 00:36:20 +02:00
8775be3393
this slightly increases the amount of memory used for any given symbol, but this increase is more than made up for if the symbol is referenced more than once in the EvalState that holds it. on average every symbol should be referenced at least twice (once to introduce a binding, once to use it), so we expect no increase in memory on average. symbol tables are limited to 2³² entries like position tables, and similar arguments apply to why overflow is not likely: 2³² symbols would require as many string instances (at 24 bytes each) and map entries (at 24 bytes or more each, assuming that the map holds on average at most one item per bucket as the docs say). a full symbol table would require at least 192GB of memory just for symbols, which is well out of reach. (an ofborg eval of nixpks today creates less than a million symbols!)
533 lines
13 KiB
C++
533 lines
13 KiB
C++
#include "nixexpr.hh"
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#include "derivations.hh"
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#include "eval.hh"
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#include "symbol-table.hh"
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#include "util.hh"
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#include <cstdlib>
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namespace nix {
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/* Displaying abstract syntax trees. */
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static void showString(std::ostream & str, std::string_view s)
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{
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str << '"';
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for (auto c : s)
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if (c == '"' || c == '\\' || c == '$') str << "\\" << c;
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else if (c == '\n') str << "\\n";
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else if (c == '\r') str << "\\r";
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else if (c == '\t') str << "\\t";
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else str << c;
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str << '"';
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}
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static void showId(std::ostream & str, std::string_view s)
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{
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if (s.empty())
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str << "\"\"";
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else if (s == "if") // FIXME: handle other keywords
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str << '"' << s << '"';
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else {
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char c = s[0];
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if (!((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_')) {
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showString(str, s);
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return;
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}
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for (auto c : s)
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if (!((c >= 'a' && c <= 'z') ||
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(c >= 'A' && c <= 'Z') ||
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(c >= '0' && c <= '9') ||
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c == '_' || c == '\'' || c == '-')) {
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showString(str, s);
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return;
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}
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str << s;
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}
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}
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std::ostream & operator << (std::ostream & str, const Symbol & sym)
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{
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showId(str, sym.s);
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return str;
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}
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void Expr::show(const SymbolTable & symbols, std::ostream & str) const
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{
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abort();
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}
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void ExprInt::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << n;
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}
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void ExprFloat::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << nf;
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}
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void ExprString::show(const SymbolTable & symbols, std::ostream & str) const
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{
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showString(str, s);
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}
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void ExprPath::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << s;
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}
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void ExprVar::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << symbols[name];
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}
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void ExprSelect::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "(";
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e->show(symbols, str);
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str << ")." << showAttrPath(symbols, attrPath);
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if (def) {
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str << " or (";
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def->show(symbols, str);
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str << ")";
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}
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}
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void ExprOpHasAttr::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "((";
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e->show(symbols, str);
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str << ") ? " << showAttrPath(symbols, attrPath) << ")";
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}
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void ExprAttrs::show(const SymbolTable & symbols, std::ostream & str) const
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{
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if (recursive) str << "rec ";
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str << "{ ";
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typedef const decltype(attrs)::value_type * Attr;
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std::vector<Attr> sorted;
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for (auto & i : attrs) sorted.push_back(&i);
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std::sort(sorted.begin(), sorted.end(), [&](Attr a, Attr b) {
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std::string_view sa = symbols[a->first], sb = symbols[b->first];
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return sa < sb;
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});
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for (auto & i : sorted) {
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if (i->second.inherited)
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str << "inherit " << symbols[i->first] << " " << "; ";
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else {
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str << symbols[i->first] << " = ";
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i->second.e->show(symbols, str);
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str << "; ";
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}
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}
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for (auto & i : dynamicAttrs) {
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str << "\"${";
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i.nameExpr->show(symbols, str);
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str << "}\" = ";
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i.valueExpr->show(symbols, str);
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str << "; ";
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}
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str << "}";
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}
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void ExprList::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "[ ";
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for (auto & i : elems) {
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str << "(";
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i->show(symbols, str);
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str << ") ";
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}
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str << "]";
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}
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void ExprLambda::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "(";
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if (hasFormals()) {
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str << "{ ";
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bool first = true;
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for (auto & i : formals->formals) {
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if (first) first = false; else str << ", ";
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str << symbols[i.name];
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if (i.def) {
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str << " ? ";
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i.def->show(symbols, str);
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}
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}
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if (formals->ellipsis) {
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if (!first) str << ", ";
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str << "...";
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}
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str << " }";
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if (arg) str << " @ ";
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}
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if (arg) str << symbols[arg];
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str << ": ";
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body->show(symbols, str);
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str << ")";
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}
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void ExprCall::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << '(';
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fun->show(symbols, str);
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for (auto e : args) {
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str << ' ';
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e->show(symbols, str);
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}
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str << ')';
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}
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void ExprLet::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "(let ";
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for (auto & i : attrs->attrs)
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if (i.second.inherited) {
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str << "inherit " << symbols[i.first] << "; ";
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}
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else {
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str << symbols[i.first] << " = ";
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i.second.e->show(symbols, str);
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str << "; ";
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}
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str << "in ";
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body->show(symbols, str);
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str << ")";
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}
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void ExprWith::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "(with ";
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attrs->show(symbols, str);
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str << "; ";
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body->show(symbols, str);
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str << ")";
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}
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void ExprIf::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "(if ";
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cond->show(symbols, str);
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str << " then ";
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then->show(symbols, str);
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str << " else ";
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else_->show(symbols, str);
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str << ")";
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}
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void ExprAssert::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "assert ";
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cond->show(symbols, str);
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str << "; ";
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body->show(symbols, str);
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}
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void ExprOpNot::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "(! ";
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e->show(symbols, str);
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str << ")";
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}
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void ExprConcatStrings::show(const SymbolTable & symbols, std::ostream & str) const
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{
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bool first = true;
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str << "(";
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for (auto & i : *es) {
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if (first) first = false; else str << " + ";
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i.second->show(symbols, str);
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}
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str << ")";
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}
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void ExprPos::show(const SymbolTable & symbols, std::ostream & str) const
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{
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str << "__curPos";
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}
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std::ostream & operator << (std::ostream & str, const Pos & pos)
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{
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if (!pos)
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str << "undefined position";
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else
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{
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auto f = format(ANSI_BOLD "%1%" ANSI_NORMAL ":%2%:%3%");
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switch (pos.origin) {
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case foFile:
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f % (const std::string &) pos.file;
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break;
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case foStdin:
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case foString:
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f % "(string)";
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break;
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default:
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throw Error("unhandled Pos origin!");
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}
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str << (f % pos.line % pos.column).str();
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}
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return str;
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}
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std::string showAttrPath(const SymbolTable & symbols, const AttrPath & attrPath)
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{
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std::ostringstream out;
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bool first = true;
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for (auto & i : attrPath) {
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if (!first) out << '.'; else first = false;
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if (i.symbol)
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out << symbols[i.symbol];
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else {
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out << "\"${";
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i.expr->show(symbols, out);
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out << "}\"";
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}
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}
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return out.str();
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}
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/* Computing levels/displacements for variables. */
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void Expr::bindVars(const EvalState & es, const StaticEnv & env)
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{
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abort();
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}
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void ExprInt::bindVars(const EvalState & es, const StaticEnv & env)
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{
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}
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void ExprFloat::bindVars(const EvalState & es, const StaticEnv & env)
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{
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}
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void ExprString::bindVars(const EvalState & es, const StaticEnv & env)
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{
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}
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void ExprPath::bindVars(const EvalState & es, const StaticEnv & env)
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{
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}
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void ExprVar::bindVars(const EvalState & es, const StaticEnv & env)
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{
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/* Check whether the variable appears in the environment. If so,
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set its level and displacement. */
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const StaticEnv * curEnv;
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Level level;
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int withLevel = -1;
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for (curEnv = &env, level = 0; curEnv; curEnv = curEnv->up, level++) {
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if (curEnv->isWith) {
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if (withLevel == -1) withLevel = level;
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} else {
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auto i = curEnv->find(name);
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if (i != curEnv->vars.end()) {
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fromWith = false;
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this->level = level;
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displ = i->second;
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return;
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}
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}
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}
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/* Otherwise, the variable must be obtained from the nearest
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enclosing `with'. If there is no `with', then we can issue an
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"undefined variable" error now. */
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if (withLevel == -1)
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throw UndefinedVarError({
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.msg = hintfmt("undefined variable '%1%'", es.symbols[name]),
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.errPos = es.positions[pos]
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});
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fromWith = true;
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this->level = withLevel;
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}
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void ExprSelect::bindVars(const EvalState & es, const StaticEnv & env)
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{
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e->bindVars(es, env);
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if (def) def->bindVars(es, env);
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for (auto & i : attrPath)
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if (!i.symbol)
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i.expr->bindVars(es, env);
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}
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void ExprOpHasAttr::bindVars(const EvalState & es, const StaticEnv & env)
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{
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e->bindVars(es, env);
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for (auto & i : attrPath)
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if (!i.symbol)
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i.expr->bindVars(es, env);
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}
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void ExprAttrs::bindVars(const EvalState & es, const StaticEnv & env)
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{
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const StaticEnv * dynamicEnv = &env;
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StaticEnv newEnv(false, &env, recursive ? attrs.size() : 0);
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if (recursive) {
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dynamicEnv = &newEnv;
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Displacement displ = 0;
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for (auto & i : attrs)
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newEnv.vars.emplace_back(i.first, i.second.displ = displ++);
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// No need to sort newEnv since attrs is in sorted order.
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for (auto & i : attrs)
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i.second.e->bindVars(es, i.second.inherited ? env : newEnv);
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}
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else
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for (auto & i : attrs)
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i.second.e->bindVars(es, env);
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for (auto & i : dynamicAttrs) {
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i.nameExpr->bindVars(es, *dynamicEnv);
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i.valueExpr->bindVars(es, *dynamicEnv);
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}
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}
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void ExprList::bindVars(const EvalState & es, const StaticEnv & env)
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{
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for (auto & i : elems)
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i->bindVars(es, env);
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}
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void ExprLambda::bindVars(const EvalState & es, const StaticEnv & env)
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{
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StaticEnv newEnv(
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false, &env,
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(hasFormals() ? formals->formals.size() : 0) +
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(!arg ? 0 : 1));
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Displacement displ = 0;
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if (arg) newEnv.vars.emplace_back(arg, displ++);
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if (hasFormals()) {
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for (auto & i : formals->formals)
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newEnv.vars.emplace_back(i.name, displ++);
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newEnv.sort();
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for (auto & i : formals->formals)
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if (i.def) i.def->bindVars(es, newEnv);
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}
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body->bindVars(es, newEnv);
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}
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void ExprCall::bindVars(const EvalState & es, const StaticEnv & env)
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{
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fun->bindVars(es, env);
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for (auto e : args)
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e->bindVars(es, env);
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}
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void ExprLet::bindVars(const EvalState & es, const StaticEnv & env)
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{
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StaticEnv newEnv(false, &env, attrs->attrs.size());
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Displacement displ = 0;
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for (auto & i : attrs->attrs)
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newEnv.vars.emplace_back(i.first, i.second.displ = displ++);
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// No need to sort newEnv since attrs->attrs is in sorted order.
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for (auto & i : attrs->attrs)
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i.second.e->bindVars(es, i.second.inherited ? env : newEnv);
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body->bindVars(es, newEnv);
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}
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void ExprWith::bindVars(const EvalState & es, const StaticEnv & env)
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{
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/* Does this `with' have an enclosing `with'? If so, record its
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level so that `lookupVar' can look up variables in the previous
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`with' if this one doesn't contain the desired attribute. */
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const StaticEnv * curEnv;
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Level level;
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prevWith = 0;
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for (curEnv = &env, level = 1; curEnv; curEnv = curEnv->up, level++)
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if (curEnv->isWith) {
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prevWith = level;
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break;
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}
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attrs->bindVars(es, env);
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StaticEnv newEnv(true, &env);
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body->bindVars(es, newEnv);
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}
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void ExprIf::bindVars(const EvalState & es, const StaticEnv & env)
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{
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cond->bindVars(es, env);
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then->bindVars(es, env);
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else_->bindVars(es, env);
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}
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void ExprAssert::bindVars(const EvalState & es, const StaticEnv & env)
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{
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cond->bindVars(es, env);
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body->bindVars(es, env);
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}
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void ExprOpNot::bindVars(const EvalState & es, const StaticEnv & env)
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{
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e->bindVars(es, env);
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}
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void ExprConcatStrings::bindVars(const EvalState & es, const StaticEnv & env)
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{
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for (auto & i : *this->es)
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i.second->bindVars(es, env);
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}
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void ExprPos::bindVars(const EvalState & es, const StaticEnv & env)
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{
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}
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/* Storing function names. */
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void Expr::setName(SymbolIdx name)
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{
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}
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void ExprLambda::setName(SymbolIdx name)
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{
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this->name = name;
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body->setName(name);
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}
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std::string ExprLambda::showNamePos(const EvalState & state) const
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{
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std::string id(name
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? concatStrings("'", state.symbols[name], "'")
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: "anonymous function");
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return fmt("%1% at %2%", id, state.positions[pos]);
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}
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/* Symbol table. */
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size_t SymbolTable::totalSize() const
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{
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size_t n = 0;
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dump([&] (const Symbol & s) { n += std::string_view(s).size(); });
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return n;
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}
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}
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