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feat(kernel/for_each): avoid recursion at for_each template

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It saves a lot of stack space.

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
This commit is contained in:
Leonardo de Moura 2013-11-18 18:08:28 -08:00
parent e10d17a0f4
commit 2951c92ad1
1 changed files with 60 additions and 41 deletions
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101
src/kernel/for_each.h
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@ -6,6 +6,8 @@ Author: Leonardo de Moura
*/
#pragma once
#include <memory>
#include <utility>
#include "util/buffer.h"
#include "kernel/expr.h"
#include "kernel/expr_sets.h"
@ -26,51 +28,68 @@ class for_each_fn {
"for_each_fn: return type of m_f is not bool");
void apply(expr const & e, unsigned offset) {
if (!CacheAtomic) {
buffer<std::pair<expr const &, unsigned>> todo;
todo.emplace_back(e, offset);
while (true) {
begin_loop:
if (todo.empty())
break;
auto p = todo.back();
todo.pop_back();
expr const & e = p.first;
unsigned offset = p.second;
if (!CacheAtomic) {
switch (e.kind()) {
case expr_kind::Constant: case expr_kind::Type: case expr_kind::Value:
case expr_kind::Var: case expr_kind::MetaVar:
m_f(e, offset);
goto begin_loop;
default:
break;
}
}
if (is_shared(e)) {
expr_cell_offset p(e.raw(), offset);
if (!m_visited)
m_visited.reset(new expr_cell_offset_set());
if (m_visited->find(p) != m_visited->end())
goto begin_loop;
m_visited->insert(p);
}
if (!m_f(e, offset))
goto begin_loop;
switch (e.kind()) {
case expr_kind::Constant: case expr_kind::Type: case expr_kind::Value:
case expr_kind::Var: case expr_kind::MetaVar:
m_f(e, offset);
return;
default:
break;
goto begin_loop;
case expr_kind::App: {
auto it = end_args(e);
auto begin = begin_args(e);
while (it != begin) {
--it;
todo.emplace_back(*it, offset);
}
goto begin_loop;
}
case expr_kind::Eq:
todo.emplace_back(eq_rhs(e), offset);
todo.emplace_back(eq_lhs(e), offset);
goto begin_loop;
case expr_kind::Lambda:
case expr_kind::Pi:
todo.emplace_back(abst_body(e), offset + 1);
todo.emplace_back(abst_domain(e), offset);
goto begin_loop;
case expr_kind::Let:
todo.emplace_back(let_body(e), offset + 1);
todo.emplace_back(let_value(e), offset);
if (let_type(e))
todo.emplace_back(let_type(e), offset);
goto begin_loop;
}
}
if (is_shared(e)) {
expr_cell_offset p(e.raw(), offset);
if (!m_visited)
m_visited.reset(new expr_cell_offset_set());
if (m_visited->find(p) != m_visited->end())
return;
m_visited->insert(p);
}
if (!m_f(e, offset))
return;
switch (e.kind()) {
case expr_kind::Constant: case expr_kind::Type: case expr_kind::Value:
case expr_kind::Var: case expr_kind::MetaVar:
return;
case expr_kind::App:
std::for_each(begin_args(e), end_args(e), [=](expr const & arg){ return apply(arg, offset); });
return;
case expr_kind::Eq:
apply(eq_lhs(e), offset);
apply(eq_rhs(e), offset);
return;
case expr_kind::Lambda:
case expr_kind::Pi:
apply(abst_domain(e), offset);
apply(abst_body(e), offset + 1);
return;
case expr_kind::Let:
if (let_type(e))
apply(let_type(e), offset);
apply(let_value(e), offset);
apply(let_body(e), offset + 1);
return;
}
}
public: