Files
carbon-lang/toolchain/parse/handle_paren_expr.cpp
T
Jon Ross-Perkins f67791cfee Separate subtree size information from parse nodes. (#4174)
Move subtree sizes over to TreeAndSubtrees, using the different
structure to represent the additional parse work that occurs, as well as
making it clear which functions require the extra information. My intent
is to make it hard to use this by accident.

The subtree size is still tracked during Parse::Tree construction. I
think a lot of that can be cleaned up, although we use it during
placeholder assignment so it may take some work. I wanted to see what
people thought about this before taking action on such a change.

I'm using a 1m line source file generated by #4124 for testing. Command
is `time bazel-bin/toolchain/install/prefix_root/bin/carbon compile
--phase=check --dump-mem-usage ~/tmp/data.carbon`

At head, what I'm seeing is:

```
...
parse_tree_.node_impls_:
  used_bytes:      61516116
  reserved_bytes:  61516116
...
Total:
  used_bytes:      447814230
  reserved_bytes:  551663894
...
1.43s user 0.14s system 99% cpu 1.565 total
```

With `Tree::Verify` disabled completely, it looks like:
```
parse_tree_.node_impls_:
  used_bytes:      41010744
  reserved_bytes:  41010744
...
Total:
  used_bytes:      427308858
  reserved_bytes:  531158522
...
1.20s user 0.13s system 99% cpu 1.332 total
```

Re-enabling just the basic verification (what is now `Tree::Verify`),
I'm seeing maybe 0.05s slower, but that's within noise for my system. I
do see variability in my timing results, and overall I think this is a
0.2s +/- 0.1s improvement versus the earlier (always testing `Extract`
code) implementation. That's opt; debug builds will be unaffected,
because the same checking occurs as before.

Note, the subtree size is a third of the node representation, which is
why I'm showing the decrease in memory usage here.
2024-07-31 19:39:45 +00:00

114 lines
3.9 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/parse/context.h"
#include "toolchain/parse/handle.h"
namespace Carbon::Parse {
auto HandleOnlyParenExpr(Context& context) -> void {
auto state = context.PopState();
// Advance past the open paren.
auto open_paren = context.ConsumeChecked(Lex::TokenKind::OpenParen);
context.AddLeafNode(NodeKind::ParenExprStart, open_paren);
state.token = open_paren;
context.PushState(state, State::OnlyParenExprFinish);
context.PushState(State::Expr);
}
static auto FinishParenExpr(Context& context,
const Context::StateStackEntry& state) -> void {
context.AddNode(NodeKind::ParenExpr, context.Consume(), state.has_error);
}
auto HandleOnlyParenExprFinish(Context& context) -> void {
auto state = context.PopState();
if (!context.PositionIs(Lex::TokenKind::CloseParen)) {
if (!state.has_error) {
CARBON_DIAGNOSTIC(UnexpectedTokenInCompoundMemberAccess, Error,
"Expected `)`.");
context.emitter().Emit(*context.position(),
UnexpectedTokenInCompoundMemberAccess);
state.has_error = true;
}
// Recover from the invalid token.
context.SkipTo(context.tokens().GetMatchedClosingToken(state.token));
}
FinishParenExpr(context, state);
}
auto HandleParenExpr(Context& context) -> void {
auto state = context.PopState();
// Advance past the open paren. The placeholder will be replaced at the end
// based on whether we determine this is a tuple or parenthesized expression.
context.AddLeafNode(NodeKind::Placeholder,
context.ConsumeChecked(Lex::TokenKind::OpenParen));
if (context.PositionIs(Lex::TokenKind::CloseParen)) {
context.PushState(state, State::TupleLiteralFinish);
} else {
context.PushState(state, State::ParenExprFinish);
context.PushState(State::ExprAfterOpenParenFinish);
context.PushState(State::Expr);
}
}
auto HandleExprAfterOpenParenFinish(Context& context) -> void {
auto state = context.PopState();
auto list_token_kind = context.ConsumeListToken(
NodeKind::TupleLiteralComma, Lex::TokenKind::CloseParen, state.has_error);
if (list_token_kind == Context::ListTokenKind::Close) {
return;
}
// We found a comma, so switch parent state to tuple handling.
auto finish_state = context.PopState();
CARBON_CHECK(finish_state.state == State::ParenExprFinish)
<< "Unexpected parent state, found: " << finish_state.state;
context.PushState(finish_state, State::TupleLiteralFinish);
// If the comma is not immediately followed by a close paren, push handlers
// for the next tuple element.
if (list_token_kind != Context::ListTokenKind::CommaClose) {
context.PushState(state, State::TupleLiteralElementFinish);
context.PushState(State::Expr);
}
}
auto HandleTupleLiteralElementFinish(Context& context) -> void {
auto state = context.PopState();
if (context.ConsumeListToken(NodeKind::TupleLiteralComma,
Lex::TokenKind::CloseParen, state.has_error) ==
Context::ListTokenKind::Comma) {
context.PushState(state);
context.PushState(State::Expr);
}
}
auto HandleParenExprFinish(Context& context) -> void {
auto state = context.PopState();
context.ReplacePlaceholderNode(state.subtree_start, NodeKind::ParenExprStart,
state.token);
FinishParenExpr(context, state);
}
auto HandleTupleLiteralFinish(Context& context) -> void {
auto state = context.PopState();
context.ReplacePlaceholderNode(state.subtree_start,
NodeKind::TupleLiteralStart, state.token);
context.AddNode(NodeKind::TupleLiteral, context.Consume(), state.has_error);
}
} // namespace Carbon::Parse