Skip to content

fix missing local variables at the bottom of blocks #75

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
masuhar wants to merge 1 commit into
base: master
Choose a base branch
from
Open

fix missing local variables at the bottom of blocks #75

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
38 changes: 31 additions & 7 deletions src/js/code-instrumentation/ast-transforms.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2157,6 +2157,13 @@ __$__.ASTTransforms = {
__$__.ASTTransforms.varEnv.addVariable(node.id.name, parent.kind, true);
}

// remember the current list of variables, which is used as
// the variables at the end of a block statement.
let variables_end = __$__.ASTTransforms.varEnv.Variables();

// discard the current frame of local variables, so that
// the later checkpoint insertion will only see the variables
// available at the beginning of the block
if (__$__.ASTTransforms.varScopes[node.type]) {
__$__.ASTTransforms.varEnv.pop();
}
Expand All @@ -2165,6 +2172,8 @@ __$__.ASTTransforms = {
let start = node.loc.start;
let end = node.loc.end;
let parent = path[path.length - 2];
// lexical variables (i.e., after popping off declared
// variables in this block)
let variables = __$__.ASTTransforms.varEnv.Variables();


Expand Down Expand Up @@ -2291,7 +2300,11 @@ __$__.ASTTransforms = {
return [
__$__.ASTTransforms.changedGraphStmt(),
__$__.ASTTransforms.makeCheckpoint(start, variables),
node,
// This embedding might create unnecessary nested blocks, which can cause
// a problem (because it uses the same `variables` at the beginning and
// the end; but there should be variables declared inside of the block.)
// However, this code seems to be dead, so I leave it as it is now.
node,
__$__.ASTTransforms.changedGraphStmt(),
__$__.ASTTransforms.makeCheckpoint(end, variables)
];
Expand All @@ -2311,7 +2324,7 @@ __$__.ASTTransforms = {
}

if (node.type === 'BlockStatement') {
return this.transformBlockStatement(start,end,variables,b,node,path);
return this.transformBlockStatement(start,end,variables,variables_end,b,node,path);
} else {
// console.log("here!");
__$__.ASTTransforms.pairCPID[__$__.ASTTransforms.checkPoint_idCounter] = __$__.ASTTransforms.checkPoint_idCounter + 1;
Expand All @@ -2327,8 +2340,16 @@ __$__.ASTTransforms = {
}
}
},
// transform all (other) block statement
transformBlockStatement(start,end,variables,b,node,path){
// transform all (other) block statement. Parameters
// `variables_begin` and `variables_end` are the list of variables
// that are accessible at the beginning of the given block `node`.
// For example, transformBlockStatement(_,_,["foo"],["foo","bar"],
// _, { s1; let bar = 123; s2; }) will return a list of AST nodes:
// [ CNG; CP(...{foo: foo}...); s1; let bar = 123;
// CNG; CP(...{foo: foo, bar: bar}...); ]
// where CNG is a statement to flag changes, CP is a checkpointing
// statement.
transformBlockStatement(start,end,variables_begin,variables_end,b,node,path){
start.column += 1;
end.column -= 1;
// when this is in a constructor and the first statement of
Expand All @@ -2348,10 +2369,10 @@ __$__.ASTTransforms = {
return b.BlockStatement(
beforeCP.concat(
[__$__.ASTTransforms.changedGraphStmt(),
__$__.ASTTransforms.makeCheckpoint(start, variables),
node,
__$__.ASTTransforms.makeCheckpoint(start, variables_begin),
...node.body, // embed the block body, no nesting
__$__.ASTTransforms.changedGraphStmt(),
__$__.ASTTransforms.makeCheckpoint(end, variables)
__$__.ASTTransforms.makeCheckpoint(end, variables_end)
]));
}
},
Expand Down Expand Up @@ -2488,6 +2509,9 @@ __$__.ASTTransforms = {
b.Identifier(__$__.ASTTransforms.checkPoint_idCounter++),
b.ObjectExpression(
variables.map(function(val) {
// for VAL, create a property name and a variable
// reference exression, namely
// {VAL: typeof VAL !== 'string' ? VAL : undefined}
let new_val = (val === temp_var) ? '__temp_' + val : val;
return b.Property(
b.Identifier(val),
Expand Down