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Run 2 passes over the AST in RewriteCallerCodeLocation
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The first pass `FindCallerLocationFunctions` will visit the param list of each function, find the params that are assigned to the default `goog.callerLocation()` function, and store these function names in a map.

The second pass `RewriteCallerLocationFunctionCalls` will visit each call node and check if it is a function call that requires a transformation. If it does, it will rewrite the call node to include the code location.

PiperOrigin-RevId: 692321563
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@rahul-kamat @copybara-github
rahul-kamat authored and copybara-github committed Nov 1, 2024
1 parent 54a62c2 commit dfa880a
Showing 1 changed file with 159 additions and 148 deletions.
307 changes: 159 additions & 148 deletions src/com/google/javascript/jscomp/RewriteCallerCodeLocation.java
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Original file line number Diff line number Diff line change
Expand Up @@ -35,7 +35,7 @@
*
* <p>i.e. `signal(0,goog.xid(path/to/file.ts:lineno:charno))`
*/
class RewriteCallerCodeLocation extends AbstractPostOrderCallback implements CompilerPass {
class RewriteCallerCodeLocation implements CompilerPass {

static final DiagnosticType JSC_CALLER_LOCATION_POSITION_ERROR =
DiagnosticType.error(
Expand Down Expand Up @@ -83,177 +83,188 @@ public RewriteCallerCodeLocation(AbstractCompiler compiler) {

@Override
public void process(Node externs, Node root) {
NodeTraversal.traverseRoots(compiler, this, externs, root);
}

@Override
public void visit(NodeTraversal t, Node n, Node parent) {
// TODO(user): Run 2 passes over the AST.
// 1st pass: visitParamListAndAddCallerLocationFunctionNames
// 2nd pass: visitCallNodeAndRewrite
switch (n.getToken()) {
case PARAM_LIST:
visitParamListAndAddCallerLocationFunctionNames(n, t);
break;
case CALL:
visitCallNodeAndRewrite(n, t);
break;
default:
break;
NodeTraversal.traverse(compiler, root, new FindCallerLocationFunctions());
if (!callerLocationFunctionNames.isEmpty()) {
NodeTraversal.traverse(compiler, root, new RewriteCallerLocationFunctionCalls());
}
}

/**
* Visits the param list of a function and checks if it contains a default value of
* goog.callerLocation. If it does, `visitParamList` stores the function name and the index of the
* param in `callerLocationFunctionNames` map.
*
* <p>Example: function signal(val, here: goog.CodeLocation = goog.callerLocation()) {}
*
* <p>`callerLocationFunctionNames` will have an entry for "signal" -> 2 (because "here" is the
* second param)
*
* @param n param list node
*/
private void visitParamListAndAddCallerLocationFunctionNames(Node n, NodeTraversal t) {
// function foo(<params>) ...
// Each item in <params> is scanned for having a default value.
// If there exists a default value, check if it is `goog.callerLocation`.
// Check if there is another optional argument that comes before the goog.callerLocation arg.
int defaultValuesCount = 0;
int paramPosition = 0; // keep track of the position of the param in the param list.
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
paramPosition++;
if (!c.isDefaultValue()) {
continue;
private class FindCallerLocationFunctions extends AbstractPostOrderCallback {

@Override
public void visit(NodeTraversal t, Node n, Node parent) {
if (n.isParamList()) {
visitParamListAndAddCallerLocationFunctionNames(n, t);
}
defaultValuesCount++;
Node call = c.getSecondChild(); // CALL node (E.g: goog.callerLocation())
if (!call.isCall()) {
continue;
if (n.isCall()) {
// Throw an error when goog.callerLocation() is NOT used as a default value in a
// function's parameter.
Node firstChild = n.getFirstChild();
if (GOOG_CALLER_LOCATION_QUALIFIED_NAME.matches(firstChild)
&& !n.getParent().isDefaultValue()) {
compiler.report(JSError.make(firstChild, JSC_CALLER_LOCATION_ERROR));
}
}
Node getProp = call.getFirstChild();
if (GOOG_CALLER_LOCATION_QUALIFIED_NAME.matches(getProp)) {
if (defaultValuesCount > 1) {
this.compiler.report(JSError.make(c, JSC_CALLER_LOCATION_POSITION_ERROR));
}

/**
* Visits the param list of a function and checks if it contains a default value of
* goog.callerLocation. If it does, `visitParamList` stores the function name and the index of
* the param in `callerLocationFunctionNames` map.
*
* <p>Example: function signal(val, here: goog.CodeLocation = goog.callerLocation()) {}
*
* <p>`callerLocationFunctionNames` will have an entry for "signal" -> 2 (because "here" is the
* second param)
*
* @param n param list node
*/
private void visitParamListAndAddCallerLocationFunctionNames(Node n, NodeTraversal t) {
// function foo(<params>) ...
// Each item in <params> is scanned for having a default value.
// If there exists a default value, check if it is `goog.callerLocation`.
// Check if there is another optional argument that comes before the goog.callerLocation arg.
int defaultValuesCount = 0;
int paramPosition = 0; // keep track of the position of the param in the param list.
for (Node c = n.getFirstChild(); c != null; c = c.getNext()) {
paramPosition++;
if (!c.isDefaultValue()) {
continue;
}
// E.g: function signal(val, here: goog.CodeLocation = goog.callerLocation()) {}
// Add ("signal" -> 2) to `callerLocationFunctionNames`
String functionName = n.getParent().getFirstChild().getQualifiedName();
if (functionName == null) {
// Anonymous functions are not allowed to use goog.callerLocation.
this.compiler.report(
JSError.make(
n.getParent().getFirstChild(), JSC_ANONYMOUS_FUNCTION_CODE_LOCATION_ERROR));
return;
defaultValuesCount++;
Node call = c.getSecondChild(); // CALL node (E.g: goog.callerLocation())
if (!call.isCall()) {
continue;
}
Node getProp = call.getFirstChild();
if (GOOG_CALLER_LOCATION_QUALIFIED_NAME.matches(getProp)) {
if (defaultValuesCount > 1) {
compiler.report(JSError.make(c, JSC_CALLER_LOCATION_POSITION_ERROR));
}
// E.g: function signal(val, here: goog.CodeLocation = goog.callerLocation()) {}
// Add ("signal" -> 2) to `callerLocationFunctionNames`
String functionName = n.getParent().getFirstChild().getQualifiedName();
if (functionName == null) {
// Anonymous functions are not allowed to use goog.callerLocation.
compiler.report(
JSError.make(
n.getParent().getFirstChild(), JSC_ANONYMOUS_FUNCTION_CODE_LOCATION_ERROR));
return;
}

FunctionVarAndParamPosition functionVarAndPosition =
new FunctionVarAndParamPosition(t.getScope().getVar(functionName), paramPosition);
callerLocationFunctionNames.put(functionName, functionVarAndPosition);
}

FunctionVarAndParamPosition functionVarAndPosition =
new FunctionVarAndParamPosition(t.getScope().getVar(functionName), paramPosition);
callerLocationFunctionNames.put(functionName, functionVarAndPosition);
}
}
}

/**
* Visits call expression nodes and checks if they require transformations. If they do, it
* rewrites the call expression node to include the code location.
*
* <p>E.g: `signal(0)` will be rewritten to `signal(0, goog.xid(path/to/file.ts:lineno:charno))`
*
* @param n call node
*/
private void visitCallNodeAndRewrite(Node n, NodeTraversal t) {
Node firstChild = n.getFirstChild();
if (firstChild == null
|| (!firstChild.isName() && !firstChild.isGetProp())
|| firstChild.getQualifiedName() == null) {
return;
}
private class RewriteCallerLocationFunctionCalls extends AbstractPostOrderCallback {

if (GOOG_CALLER_LOCATION_QUALIFIED_NAME.matches(firstChild)
&& !n.getParent().isDefaultValue()) {
this.compiler.report(JSError.make(firstChild, JSC_CALLER_LOCATION_ERROR));
@Override
public void visit(NodeTraversal t, Node n, Node parent) {
if (n.isCall()) {
visitCallNodeAndRewrite(n, t);
}
}

// Check if the call-site is calling a callerLocation function.
// E.g: signal(0); name = "signal"
String name = firstChild.getQualifiedName();

// ClosureRewriteModule pass will run before this pass and will rename exported function names
// and aliases in goog.modules.
// E.g:
// function name = module$contents$google3$javascript$apps$wiz$signals$signal_signal
// call node name = module$exports$google3$javascript$apps$wiz$signals$signal.signal
String moduleContentsName =
name.replace('.', '_').replace("module$exports$", "module$contents$");

if (!callerLocationFunctionNames.containsKey(moduleContentsName)) {
return;
}
/**
* Visits call expression nodes and checks if they require transformations. If they do, it
* rewrites the call expression node to include the code location.
*
* <p>E.g: `signal(0)` will be rewritten to `signal(0, goog.xid(path/to/file.ts:lineno:charno))`
*
* @param n call node
*/
private void visitCallNodeAndRewrite(Node n, NodeTraversal t) {
Node firstChild = n.getFirstChild();
if (firstChild == null
|| (!firstChild.isName() && !firstChild.isGetProp())
|| firstChild.getQualifiedName() == null) {
return;
}

FunctionVarAndParamPosition functionVarAndPosition =
callerLocationFunctionNames.get(moduleContentsName);
// Check if the call-site is calling a callerLocation function.
// E.g: signal(0); name = "signal"
String name = firstChild.getQualifiedName();

Var callerLocationFunction = functionVarAndPosition.getFunctionVar();
Var calleeFunction = t.getScope().getVar(moduleContentsName);
if (!Objects.equals(calleeFunction, callerLocationFunction)) {
return;
}
// ClosureRewriteModule pass will run before this pass and will rename exported function names
// and aliases in goog.modules.
// E.g:
// function name = module$contents$google3$javascript$apps$wiz$signals$signal_signal
// call node name = module$exports$google3$javascript$apps$wiz$signals$signal.signal
String moduleContentsName =
name.replace('.', '_').replace("module$exports$", "module$contents$");

// Check if the argument is provided.
// E.g:
// function signal(val, here: goog.CodeLocation = goog.callerLocation()) {}
// signal(0, xid('path/to/file.ts:25')); // goog.CodeLocation is provided
int positionOfCallerLocationArg = functionVarAndPosition.getParamPosition();
int numberOfArgs = n.getChildCount() - 1; // -1 for the firstChild which is the function name.
if (numberOfArgs >= positionOfCallerLocationArg) {
// goog.CodeLocation is provided as an argument, we will not rewrite this call-site.
// If `undefined` is passed in as an argument to goog.CodeLocation, we will throw an error.
// Otherwise continue without rewriting.
JSType jsType = n.getChildAtIndex(positionOfCallerLocationArg).getJSType();
if (jsType != null && jsType.isExplicitlyVoidable()) {
// user is passing in undefined as an argument to goog.CodeLocation
this.compiler.report(JSError.make(firstChild, JSC_UNDEFINED_CODE_LOCATION_ERROR));
if (!callerLocationFunctionNames.containsKey(moduleContentsName)) {
return;
}

return;
}

// create the goog.xid(path/to/file.ts:lineno:charno) and add it as the last parameter.
Node xidCall = createGoogXidFilePathNode(n);
compiler.reportChangeToEnclosingScope(n);
n.addChildToBack(xidCall);
}

/**
* Creates a call node for "goog.xid(path/to/file.ts:lineno:charno)"
*
* @param n call node of a function that needs to be rewritten to include the code location
* @return call node including code location i.e. "goog.xid(path/to/file.ts:lineno:charno)"
*/
private Node createGoogXidFilePathNode(Node n) {
// googNode is "goog"
Node googNode = IR.name("goog");
googNode.srcrefIfMissing(n);
FunctionVarAndParamPosition functionVarAndPosition =
callerLocationFunctionNames.get(moduleContentsName);

// googXid is "goog.xid" node
Node googXid = astFactory.createGetPropWithUnknownType(googNode, "xid");
googXid.srcrefIfMissing(n);
Var callerLocationFunction = functionVarAndPosition.getFunctionVar();
Var calleeFunction = t.getScope().getVar(moduleContentsName);
if (!Objects.equals(calleeFunction, callerLocationFunction)) {
return;
}

// callNode is "goog.xid()" node
Node callNode = astFactory.createCallWithUnknownType(googXid);
callNode.srcrefIfMissing(n);
// Check if the argument is provided.
// E.g:
// function signal(val, here: goog.CodeLocation = goog.callerLocation()) {}
// signal(0, xid('path/to/file.ts:25')); // goog.CodeLocation is provided
int positionOfCallerLocationArg = functionVarAndPosition.getParamPosition();
int numberOfArgs = n.getChildCount() - 1; // -1 for the firstChild which is the function name.
if (numberOfArgs >= positionOfCallerLocationArg) {
// goog.CodeLocation is provided as an argument, we will not rewrite this call-site.
// If `undefined` is passed in as an argument to goog.CodeLocation, we will throw an error.
// Otherwise continue without rewriting.
JSType jsType = n.getChildAtIndex(positionOfCallerLocationArg).getJSType();
if (jsType != null && jsType.isExplicitlyVoidable()) {
// user is passing in undefined as an argument to goog.CodeLocation
compiler.report(JSError.make(firstChild, JSC_UNDEFINED_CODE_LOCATION_ERROR));
}

// stringNode is "path/to/file.ts:lineno:charno" node
Node stringNode =
astFactory.createString(n.getSourceFileName() + ":" + n.getLineno() + ":" + n.getCharno());
stringNode.srcrefIfMissing(n);
return;
}

// turns callNode from "goog.xid()" to "goog.xid(path/to/file.ts:lineno:charno)"
callNode.addChildToBack(stringNode);
// create the goog.xid(path/to/file.ts:lineno:charno) and add it as the last parameter.
Node xidCall = createGoogXidFilePathNode(n);
compiler.reportChangeToEnclosingScope(n);
n.addChildToBack(xidCall);
}

return callNode;
/**
* Creates a call node for "goog.xid(path/to/file.ts:lineno:charno)"
*
* @param n call node of a function that needs to be rewritten to include the code location
* @return call node including code location i.e. "goog.xid(path/to/file.ts:lineno:charno)"
*/
private Node createGoogXidFilePathNode(Node n) {
// googNode is "goog"
Node googNode = IR.name("goog");
googNode.srcrefIfMissing(n);

// googXid is "goog.xid" node
Node googXid = astFactory.createGetPropWithUnknownType(googNode, "xid");
googXid.srcrefIfMissing(n);

// callNode is "goog.xid()" node
Node callNode = astFactory.createCallWithUnknownType(googXid);
callNode.srcrefIfMissing(n);

// stringNode is "path/to/file.ts:lineno:charno" node
Node stringNode =
astFactory.createString(
n.getSourceFileName() + ":" + n.getLineno() + ":" + n.getCharno());
stringNode.srcrefIfMissing(n);

// turns callNode from "goog.xid()" to "goog.xid(path/to/file.ts:lineno:charno)"
callNode.addChildToBack(stringNode);

return callNode;
}
}

/**
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