1451343 - [BinAST] Verify name capture

Status: RESOLVED FIXED

(Core :: JavaScript Engine, enhancement, P3)

Description

[David Teller [:Yoric] - still alive but not very active]

Bug 1437004 and bug 1439855 implement most of the BinAST parser (for a subset of JavaScript), but are still missing verification of captured names.

We need to implement this before releasing.

Comment 1

[Eric Faust [:efaust]]

I have patches for this! I didn't know there was talk of someone else implementing it, so I did >.>. Will put it up for review this afternoon, so Yoric and arai can take a look at it.

Comment 2

[David Teller [:Yoric] - still alive but not very active]

In this case, reassigning to efaust.

Comment 3

[Eric Faust [:efaust]]

Attachment: Part 1: Properly use provided capture information

Comment 4

[Eric Faust [:efaust]]

Attachment: Part 2: Verify capture information when parsing scopes.

Comment 5

[David Teller [:Yoric] - still alive but not very active]

Comment on attachment 8970816 [details] [diff] [review]
Part 1: Properly use provided capture information

Review of attachment 8970816 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/frontend/BinSource.cpp
@@ +198,4 @@
>      return result;
>  }
>  
> +static bool TryMarkCaptureInScope(ParseContext::Scope& scope, HandleAtom atom)

What does the return value mean? Is it an error? If so, shouldn't you propagate it in all cases?

@@ +199,5 @@
>  }
>  
> +static bool TryMarkCaptureInScope(ParseContext::Scope& scope, HandleAtom atom)
> +{
> +    auto name = scope.lookupDeclaredName(atom);

We can have `atom == nullptr`, right? Shouldn't we bailout in that case?

@@ +224,5 @@
> +            MOZ_ASSERT(parseContext_->isFunctionBox());
> +
> +            if (parseContext_->functionBox()->function()->isNamedLambda()) {
> +                if (TryMarkCaptureInScope(parseContext_->namedLambdaScope(), name))
> +                    continue;

Why don't we propagate the error (if it's an error)?

@@ +234,5 @@
> +        }
> +
> +        if (kind == BinKind::AssertedVarScope) {
> +            if (TryMarkCaptureInScope(parseContext_->varScope(), name))
> +                continue;

Here, too?

Comment 6

[David Teller [:Yoric] - still alive but not very active]

Comment on attachment 8970817 [details] [diff] [review]
Part 2: Verify capture information when parsing scopes.

Review of attachment 8970817 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/frontend/BinSource.cpp
@@ +154,1 @@
>  BinASTParser<Tok>::buildFunction(const size_t start, const BinKind kind, ParseNode* name,

Nit: Could you take the opportunity to document somewhere that we call this method after creating the scope?

@@ +154,5 @@
>  BinASTParser<Tok>::buildFunction(const size_t start, const BinKind kind, ParseNode* name,
>                                   ParseNode* params, ParseNode* body, FunctionBox* funbox)
>  {
> +    // Check all our bindings before doing anything else.
> +    MOZ_TRY(checkFunctionClosedVars());

This doesn't check arguments, right? Do we need to check them, too? If not, could you document why?

::: js/src/frontend/BinSource.h
@@ +195,4 @@
>          DeclarationKind kind);
>      MOZ_MUST_USE JS::Result<Ok> parseAndUpdateCapturedNames(const BinKind kind);
>      MOZ_MUST_USE JS::Result<Ok> checkBinding(JSAtom* name);
> +    MOZ_MUST_USE JS::Result<Ok> checkClosedVars(ParseContext::Scope& scope);

Nit: A little documentation would be nice, now that there is more than one person working on that code :)

::: js/src/frontend/BinSource.yaml
@@ +688,4 @@
>      build: |
>          if (!IsIdentifier(name))
>              return raiseError("Invalid identifier");
> +        BINJS_TRY(usedNames_.noteUse(cx_, name, parseContext_->scriptId(), parseContext_->innermostScope()->id()));

Out of curiosity, what's that for?

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/03130e40886b
Part 1: Use provided capture information. (r=Yoric)
https://hg.mozilla.org/integration/mozilla-inbound/rev/cf0675c2f362
Part 2: Check annotated closed vars against known uses. (r=Yoric)

Comment 8

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/03130e40886b
https://hg.mozilla.org/mozilla-central/rev/cf0675c2f362