report Variables

The report keyword specifies variables whose values should be flushed. When monitoring an application execution, data describing observations should be stored in a report variable to make use of this flushing feature.

Using report is really shorthand for report unshared, see [unshared] variable documentation.

The default behavior of this "flush" is to print to the console (the core Whamm library uses WASI to do this). This will be done at the end of program execution with the final values of the variables.

For example:

report var count;
wasm:opcode:call:before {
    // count the number of times the `call` opcode was used during the application's dynamic execution.
    // (a single global count)
    count++;
}