byteSize-of-symbol.js

Enable keyboard shortcuts

// |jit-test| skip-if: !getBuildConfiguration("moz-memory")

// Run this test only if we're using jemalloc. Other malloc implementations

// exhibit surprising behaviors. For example, 32-bit Fedora builds have

// non-deterministic allocation sizes.

// Check JS::ubi::Node::size results for symbols.

// We actually hard-code specific sizes into this test, even though they're

// implementation details, because in practice there are only two architecture

// variants to consider (32-bit and 64-bit), and if these sizes change, that's

// something SpiderMonkey hackers really want to know; they're supposed to be

// stable.

const SIZE_OF_SYMBOL = getBuildConfiguration("pointer-byte-size") == 4 ? 16 : 16;

// Without a description.

assertEq(byteSize(Symbol()), SIZE_OF_SYMBOL);

// With a description.

assertEq(byteSize(Symbol("This is a relatively long description to be passed to "

                         + "Symbol() but it doesn't matter because it just gets "

                         + "interned as a JSAtom* anyways.")),

         SIZE_OF_SYMBOL);