lean4-htt/src/library/compiler/vm_compiler.cpp
Leonardo de Moura 2bd400964c feat(library/vm/vm): store arguments in reverse order on the stack
It simplifies the code for handling closures.
2016-05-13 10:54:29 -07:00

313 lines
11 KiB
C++

/*
Copyright (c) 2016 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "util/fresh_name.h"
#include "util/sstream.h"
#include "kernel/instantiate.h"
#include "library/constants.h"
#include "library/trace.h"
#include "library/vm/vm.h"
#include "library/vm/optimize.h"
#include "library/util.h"
#include "library/compiler/simp_inductive.h"
#include "library/compiler/erase_irrelevant.h"
#include "library/compiler/nat_value.h"
#include "library/compiler/preprocess.h"
namespace lean {
class vm_compiler_fn {
environment m_env;
buffer<vm_instr> & m_code;
void emit(vm_instr const & i) {
m_code.push_back(i);
}
unsigned next_pc() const {
return m_code.size();
}
expr mk_local(name const & n) {
return ::lean::mk_local(n, mk_neutral_expr());
}
void compile_args(unsigned nargs, expr const * args, unsigned bpz, name_map<unsigned> const & m) {
for (unsigned i = 0; i < nargs; i++, bpz++) {
compile(args[i], bpz, m);
}
}
void compile_rev_args(unsigned nargs, expr const * args, unsigned bpz, name_map<unsigned> const & m) {
unsigned i = nargs;
while (i > 0) {
--i;
compile(args[i], bpz, m);
bpz++;
}
}
void compile_global(vm_decl const & decl, unsigned nargs, expr const * args, unsigned bpz, name_map<unsigned> const & m) {
compile_rev_args(nargs, args, bpz, m);
lean_assert(nargs <= decl.get_arity());
if (decl.get_arity() == nargs) {
if (decl.is_builtin())
emit(mk_invoke_builtin_instr(decl.get_idx()));
else
emit(mk_invoke_global_instr(decl.get_idx()));
} else {
emit(mk_closure_instr(decl.get_idx(), nargs));
}
}
[[ noreturn ]] void throw_unknown_constant(name const & n) {
throw exception(sstream() << "code generation failed, VM does not have code for '" << n << "'");
}
void compile_constant(expr const & e) {
name const & n = const_name(e);
if (is_neutral_expr(e)) {
emit(mk_sconstructor_instr(0));
} else if (is_unreachable_expr(e)) {
emit(mk_unreachable_instr());
} else if (n == get_nat_zero_name()) {
emit(mk_num_instr(mpz(0)));
} else if (auto idx = is_internal_cnstr(e)) {
emit(mk_sconstructor_instr(*idx));
} else if (optional<vm_decl> decl = get_vm_decl(m_env, n)) {
compile_global(*decl, 0, nullptr, 0, name_map<unsigned>());
} else {
throw_unknown_constant(n);
}
}
void compile_local(expr const & e, name_map<unsigned> const & m) {
unsigned idx = *m.find(mlocal_name(e));
emit(mk_push_instr(idx));
}
void compile_cases_on(expr const & e, unsigned bpz, name_map<unsigned> const & m) {
buffer<expr> args;
expr fn = get_app_args(e, args);
lean_assert(is_constant(fn));
name const & fn_name = const_name(fn);
unsigned num;
if (fn_name == get_nat_cases_on_name()) {
num = 2;
} else {
lean_assert(is_internal_cases(fn));
num = *is_internal_cases(fn);
}
lean_assert(args.size() == num + 1);
lean_assert(num >= 1);
/** compile major premise */
compile(args[0], bpz, m);
unsigned cases_pos = next_pc();
buffer<unsigned> cases_args;
buffer<unsigned> goto_pcs;
cases_args.resize(num, 0);
if (fn_name == get_nat_cases_on_name())
emit(mk_nat_cases_instr(0, 0));
else if (num == 1)
emit(mk_cases1_instr());
else if (num == 2)
emit(mk_cases2_instr(0, 0));
else
emit(mk_casesn_instr(cases_args.size(), cases_args.data()));
for (unsigned i = 1; i < args.size(); i++) {
cases_args[i - 1] = next_pc();
expr b = args[i];
buffer<expr> locals;
name_map<unsigned> new_m = m;
unsigned new_bpz = bpz;
while (is_lambda(b)) {
name n = mk_fresh_name();
new_m.insert(n, new_bpz);
locals.push_back(mk_local(n));
new_bpz++;
b = binding_body(b);
}
b = instantiate_rev(b, locals.size(), locals.data());
compile(b, new_bpz, new_m);
if (locals.size() > 0)
emit(mk_drop_instr(locals.size()));
// if it is not the last case, we need to use a goto
if (i + 1 < args.size()) {
goto_pcs.push_back(next_pc());
emit(mk_goto_instr(0)); // fix later
}
}
/* Fix cases instruction pc's */
if (num >= 2) {
for (unsigned i = 0; i < cases_args.size(); i++)
m_code[cases_pos].set_pc(i, cases_args[i]);
}
unsigned end_pc = next_pc();
/* Fix goto instruction pc's */
for (unsigned i = 0; i < goto_pcs.size(); i++) {
m_code[goto_pcs[i]].set_goto_pc(end_pc);
}
}
void compile_cnstr(expr const & e, unsigned bpz, name_map<unsigned> const & m) {
buffer<expr> args;
expr const & fn = get_app_args(e, args);
lean_assert(is_internal_cnstr(fn));
unsigned cidx = *is_internal_cnstr(fn);
compile_args(args.size(), args.data(), bpz, m);
emit(mk_constructor_instr(cidx, get_app_num_args(e)));
}
void compile_proj(expr const & e, unsigned bpz, name_map<unsigned> const & m) {
buffer<expr> args;
expr const & fn = get_app_args(e, args);
lean_assert(is_internal_proj(fn));
unsigned idx = *is_internal_proj(fn);
lean_assert(args.size() >= 1);
compile_rev_args(args.size() - 1, args.data() + 1, bpz, m);
bpz += args.size() - 1;
compile(args[0], bpz, m);
emit(mk_proj_instr(idx));
if (args.size() > 1)
emit(mk_invoke_instr(args.size() - 1));
}
void compile_fn_call(expr const & e, unsigned bpz, name_map<unsigned> const & m) {
buffer<expr> args;
expr fn = get_app_args(e, args);
if (!is_constant(fn)) {
compile_rev_args(args.size(), args.data(), bpz+1, m);
compile(fn, bpz, m);
emit(mk_invoke_instr(args.size()));
return;
} else if (is_constant(fn)) {
if (optional<vm_decl> decl = get_vm_decl(m_env, const_name(fn))) {
compile_global(*decl, args.size(), args.data(), bpz, m);
} else {
throw_unknown_constant(const_name(fn));
}
} else {
lean_unreachable();
}
}
void compile_app(expr const & e, unsigned bpz, name_map<unsigned> const & m) {
expr const & fn = get_app_fn(e);
if (is_internal_cases(fn) || is_constant(fn, get_nat_cases_on_name())) {
compile_cases_on(e, bpz, m);
} else if (is_internal_cnstr(fn)) {
compile_cnstr(e, bpz, m);
} else if (is_internal_proj(fn)) {
compile_proj(e, bpz, m);
} else {
compile_fn_call(e, bpz, m);
}
}
void compile_let(expr e, unsigned bpz, name_map<unsigned> const & m) {
unsigned counter = 0;
buffer<expr> locals;
name_map<unsigned> new_m = m;
while (is_let(e)) {
counter++;
compile(instantiate_rev(let_value(e), locals.size(), locals.data()), bpz, new_m);
name n = mk_fresh_name();
new_m.insert(n, bpz);
locals.push_back(mk_local(n));
bpz++;
e = let_body(e);
}
lean_assert(counter > 0);
compile(instantiate_rev(e, locals.size(), locals.data()), bpz, new_m);
emit(mk_drop_instr(counter));
}
void compile_macro(expr const & e) {
if (is_nat_value(e)) {
emit(mk_num_instr(get_nat_value_value(e)));
} else {
throw exception("code generation failed, unexpected kind of macro has been found");
}
}
void compile(expr const & e, unsigned bpz, name_map<unsigned> const & m) {
switch (e.kind()) {
case expr_kind::Var: lean_unreachable();
case expr_kind::Sort: lean_unreachable();
case expr_kind::Meta: lean_unreachable();
case expr_kind::Pi: lean_unreachable();
case expr_kind::Lambda: lean_unreachable();
case expr_kind::Macro: compile_macro(e); break;
case expr_kind::Constant: compile_constant(e); break;
case expr_kind::Local: compile_local(e, m); break;
case expr_kind::App: compile_app(e, bpz, m); break;
case expr_kind::Let: compile_let(e, bpz, m); break;
}
}
unsigned get_arity(expr e) {
unsigned r = 0;
while (is_lambda(e)) {
r++;
e = binding_body(e);
}
return r;
}
public:
vm_compiler_fn(environment const & env, buffer<vm_instr> & code):
m_env(env), m_code(code) {}
unsigned operator()(expr e) {
buffer<expr> locals;
unsigned bpz = 0;
unsigned arity = get_arity(e);
unsigned i = arity;
name_map<unsigned> m;
while (is_lambda(e)) {
name n = mk_fresh_name();
i--;
m.insert(n, i);
locals.push_back(mk_local(n));
bpz++;
e = binding_body(e);
}
e = instantiate_rev(e, locals.size(), locals.data());
compile(e, bpz, m);
emit(mk_ret_instr());
return arity;
}
};
environment vm_compile(environment const & env, buffer<pair<name, expr>> const & procs) {
environment new_env = env;
for (auto const & p : procs) {
new_env = reserve_vm_index(new_env, p.first, p.second);
}
for (auto const & p : procs) {
buffer<vm_instr> code;
vm_compiler_fn gen(new_env, code);
unsigned arity = gen(p.second);
optimize(new_env, code);
lean_trace(name({"compiler", "code_gen"}), tout() << " " << p.first << " " << arity << "\n";
display_vm_code(tout().get_stream(), new_env, code.size(), code.data()););
new_env = update_vm_code(new_env, p.first, code.size(), code.data());
}
return new_env;
}
environment vm_compile(environment const & env, declaration const & d) {
buffer<pair<name, expr>> procs;
preprocess(env, d, procs);
return vm_compile(env, procs);
}
void initialize_vm_compiler() {
register_trace_class({"compiler", "code_gen"});
}
void finalize_vm_compiler() {
}
}