private Result assertThat(String expr, String type, String decls)
throws UnableToCompleteException {
ConstantsAssumption.Updater updater =
new ConstantsAssumption.Updater(new ConstantsAssumption());
String codeSnippet = decls;
codeSnippet += "return " + expr + ";";
JProgram program = compileSnippet(type, codeSnippet);
JMethod mainMethod = findMainMethod(program);
JBlock block = ((JMethodBody) mainMethod.getBody()).getBlock();
List<JStatement> statements = block.getStatements();
// TODO: not a pretty assumption detection.
for (JStatement stmt : statements) {
if (!(stmt instanceof JDeclarationStatement)) {
continue;
}
JDeclarationStatement decl = (JDeclarationStatement) stmt;
if (decl.getInitializer() != null) {
updater.set(decl.getVariableRef().getTarget(), (JValueLiteral) decl.getInitializer());
}
}
JReturnStatement returnStatement = (JReturnStatement) statements.get(statements.size() - 1);
return new Result(ExpressionEvaluator.evaluate(returnStatement.getExpr(), updater.unwrap()));
}
@Override
public void endVisit(JDeclarationStatement x, Context ctx) {
super.endVisit(x, ctx);
lValues.pop();
// The variable may have been pruned.
if (isVariablePruned(x.getVariableRef().getTarget())) {
JExpression replacement =
makeReplacementForAssignment(x.getSourceInfo(), x.getVariableRef(), x.getInitializer());
ctx.replaceMe(replacement.makeStatement());
}
}
/**
* Creates a JMultiExpression from a set of JExpressionStatements, optionally terminated by a
* JReturnStatement. If the method doesn't match this pattern, it returns <code>null</code>.
*
* <p>If a method has a non-void return statement and can be represented as a multi-expression,
* the output of the multi-expression will be the return expression of the method. If the method
* is void, the output of the multi-expression should be considered undefined.
*/
private List<JExpression> extractExpressionsFromBody(JMethodBody body) {
List<JExpression> expressions = Lists.newArrayList();
CloneCalleeExpressionVisitor cloner = new CloneCalleeExpressionVisitor();
for (JStatement stmt : body.getStatements()) {
if (stmt instanceof JDeclarationStatement) {
JDeclarationStatement declStatement = (JDeclarationStatement) stmt;
if (!(declStatement.getVariableRef() instanceof JLocalRef)) {
return null;
}
JExpression initializer = declStatement.getInitializer();
if (initializer == null) {
continue;
}
JLocal local = (JLocal) declStatement.getVariableRef().getTarget();
JExpression clone =
new JBinaryOperation(
stmt.getSourceInfo(),
local.getType(),
JBinaryOperator.ASG,
new JLocalRef(declStatement.getVariableRef().getSourceInfo(), local),
cloner.cloneExpression(initializer));
expressions.add(clone);
} else if (stmt instanceof JExpressionStatement) {
JExpressionStatement exprStmt = (JExpressionStatement) stmt;
JExpression expr = exprStmt.getExpr();
JExpression clone = cloner.cloneExpression(expr);
expressions.add(clone);
} else if (stmt instanceof JReturnStatement) {
JReturnStatement returnStatement = (JReturnStatement) stmt;
JExpression expr = returnStatement.getExpr();
if (expr != null) {
JExpression clone = cloner.cloneExpression(expr);
clone = maybeCast(clone, body.getMethod().getType());
expressions.add(clone);
}
// We hit an unconditional return; no need to evaluate anything else.
break;
} else {
// Any other kind of statement won't be inlinable.
return null;
}
}
return expressions;
}
@Override
public boolean visit(JDeclarationStatement x, Context ctx) {
super.visit(x, ctx);
lValues.push(x.getVariableRef());
return true;
}