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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/**
* Embedding-provided build ID information, used by SpiderMonkey to tag cached
* compilation data so that cached data can be reused when possible, or
* discarded and regenerated if necessary.
*/
#ifndef js_BuildId_h
#define js_BuildId_h
#include "jstypes.h" // JS_PUBLIC_API
#include "js/Vector.h" // js::Vector
namespace js {
class SystemAllocPolicy;
} // namespace js
namespace JS {
/** Vector of characters used for holding build ids. */
using BuildIdCharVector = js::Vector<char, 0, js::SystemAllocPolicy>;
/**
* Return the buildId (represented as a sequence of characters) associated with
* the currently-executing build. If the JS engine is embedded such that a
* single cache entry can be observed by different compiled versions of the JS
* engine, it is critical that the buildId shall change for each new build of
* the JS engine.
*/
using BuildIdOp = bool (*)(BuildIdCharVector* buildId);
/**
* Embedder hook to set the buildId-generating function.
*/
extern JS_PUBLIC_API void SetProcessBuildIdOp(BuildIdOp buildIdOp);
/**
* Some cached data is, in addition to being build-specific, CPU-specific: the
* cached data depends on CPU features like a particular level of SSE support.
*
* This function produces a buildId that includes:
*
* * the buildId defined by the embedder-provided BuildIdOp set by
* JS::SetProcessBuildIdOp, and
* * CPU feature information for the current CPU.
*
* Embedders may use this function to tag cached data whose validity depends
* on having consistent buildId *and* on the CPU supporting features identical
* to those in play when the cached data was computed.
*/
[[nodiscard]] extern JS_PUBLIC_API bool GetOptimizedEncodingBuildId(
BuildIdCharVector* buildId);
/**
* Script bytecode is dependent on the buildId and a few other things.
*
* This function produces a buildId that includes:
*
* * The buildId defined by the embedder-provided BuildIdOp set by
* JS::SetProcessBuildIdOp.
* * Additional bytes describing things like endianness, pointer size and
* other state XDR buffers depend on.
*
* Note: this value may depend on runtime preferences so isn't guaranteed to be
* stable across restarts.
*
* Embedders should use this function to tag transcoded bytecode.
* See Transcoding.h.
*/
[[nodiscard]] extern JS_PUBLIC_API bool GetScriptTranscodingBuildId(
BuildIdCharVector* buildId);
} // namespace JS
#endif /* js_BuildId_h */
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