The initial problem reported in the bug is that we try to speculatively load a
bareword import before the import map is dynamically inserted that makes that
load valid. The load fails and then we cache the failure in the module map.
The more general problem is that import maps change the locations that imports
are resolved to so if when there is a dynamically inserted import map
speculative preload may load and cache the wrong things.
This patch fixes this problem by removing any preloaded modules from the module
map when an import map is registered.
Previously we used to do something like this but it was changed because I
wasn't confident that it wouldn't remove too much. However it appears that this
is necessary to handle this situation, so it's implemented here but with more
checks that it only removes preloaded modules. This is handled by adding extra
flags where necessary so we have the information on hand to check.
I've made these diagnostic asserts so that this actually gets check in real use.
Differential Revision: https://phabricator.services.mozilla.com/D202611
This change adds the `LoadedScript` in the memory reporter.
This change is needed as we are looking into using the `LoadedScript` as a value
of the `SharedSubResourceCache`. The upcoming cache requires the Value to be
registered in the memory reporter, providing a `SizeOfInlcudingThis` function.
Differential Revision: https://phabricator.services.mozilla.com/D203132
The initial problem reported in the bug is that we try to speculatively load a
bareword import before the import map is dynamically inserted that makes that
load valid. The load fails and then we cache the failure in the module map.
The more general problem is that import maps change the locations that imports
are resolved to so if when there is a dynamically inserted import map
speculative preload may load and cache the wrong things.
This patch fixes this problem by removing any preloaded modules from the module
map when an import map is registered.
Previously we used to do something like this but it was changed because I
wasn't confident that it wouldn't remove too much. However it appears that this
is necessary to handle this situation, so it's implemented here but with more
checks that it only removes preloaded modules. This is handled by adding extra
flags where necessary so we have the information on hand to check.
I've made these diagnostic asserts so that this actually gets check in real use.
Differential Revision: https://phabricator.services.mozilla.com/D202611
The initial problem reported in the bug is that we try to speculatively load a
bareword import before the import map is dynamically inserted that makes that
load valid. The load fails and then we cache the failure in the module map.
The more general problem is that import maps change the locations that imports
are resolved to so if when there is a dynamically inserted import map
speculative preload may load and cache the wrong things.
This patch fixes this problem by removing any preloaded modules from the module
map when an import map is registered.
Previously we used to do something like this but it was changed because I
wasn't confident that it wouldn't remove too much. However it appears that this
is necessary to handle this situation, so it's implemented here but with more
checks that it only removes preloaded modules. This is handled by adding extra
flags where necessary so we have the information on hand to check.
I've made these diagnostic asserts so that this actually gets check in real use.
Differential Revision: https://phabricator.services.mozilla.com/D202611
We are looking into caching loaded script in memory. To do so we need something
to cache.
At the moment, the `ScriptLoadRequest` structure hold all the fields which are
loaded, and used before executing JavaScript code. Then, the `ScriptLoadRequest`
is not guaranteed to out-live the first execution.
Therefore, we have to move fields out of the `ScriptLoadRequest` such that they
can later be used by any caching mechanism. The `LoadedScript` is the closest
existing structure which exists which fit the description.
This patch moves fields out of the ScriptLoadRequest into the `LoadedScript`,
which already has a `LoadedScript` field.
The `LoadedScript` field is initialized sooner, when the `ScriptLoadRequest` is
created, to be subsituted later by a real cache implementation. At the moment
the function `ScriptLoadRequest::NoCacheEntryFound` is used as a placeholder to
change the state of the `ScriptLoadRequest` from `CheckingCache` to `Fetching`.
Existing initializations are replaced by assertions to fail in debug build if
the current patch does not reproduce the expected state properly.
The `LoadedScript` get fields such as the source text, the text length, the
bytecode buffer (which also contains SRI), and the offset at which the bytecode
starts within the bytecode buffer. As these fields are no longer reachable by
name, multiple accessors are added to work-around the issue. Using this as an
opportunity to add extra assertions as part of these accessors.
A new class named `LoadedScriptDelegate` is added to re-add, by inheritance, all
the accessors which used to be part of `ScriptLoadRequest` as methods which are
delegating to the field which is holding the `LoadedScript`. This class is using
templates to avoid virtual inheritance which might hinder inlining, especially
since `ScriptLoadRequest` cannot be made final, as `ModuleLoadRequest` extends
it.
The `ScriptFetchOptions` structure is moved to its own file to solve C++ include
issues.
Differential Revision: https://phabricator.services.mozilla.com/D197921
We are looking into caching loaded script in memory. To do so we need something
to cache.
At the moment, the `ScriptLoadRequest` structure hold all the fields which are
loaded, and used before executing JavaScript code. Then, the `ScriptLoadRequest`
is not guaranteed to out-live the first execution.
Therefore, we have to move fields out of the `ScriptLoadRequest` such that they
can later be used by any caching mechanism. The `LoadedScript` is the closest
existing structure which exists which fit the description.
This patch moves fields out of the ScriptLoadRequest into the `LoadedScript`,
which already has a `LoadedScript` field.
The `LoadedScript` field is initialized sooner, when the `ScriptLoadRequest` is
created, to be subsituted later by a real cache implementation. At the moment
the function `ScriptLoadRequest::NoCacheEntryFound` is used as a placeholder to
change the state of the `ScriptLoadRequest` from `CheckingCache` to `Fetching`.
Existing initializations are replaced by assertions to fail in debug build if
the current patch does not reproduce the expected state properly.
The `LoadedScript` get fields such as the source text, the text length, the
bytecode buffer (which also contains SRI), and the offset at which the bytecode
starts within the bytecode buffer. As these fields are no longer reachable by
name, multiple accessors are added to work-around the issue. Using this as an
opportunity to add extra assertions as part of these accessors.
A new class named `LoadedScriptDelegate` is added to re-add, by inheritance, all
the accessors which used to be part of `ScriptLoadRequest` as methods which are
delegating to the field which is holding the `LoadedScript`. This class is using
templates to avoid virtual inheritance which might hinder inlining, especially
since `ScriptLoadRequest` cannot be made final, as `ModuleLoadRequest` extends
it.
The `ScriptFetchOptions` structure is moved to its own file to solve C++ include
issues.
Differential Revision: https://phabricator.services.mozilla.com/D163615
We are looking into caching loaded script in memory. To do so we need something
to cache.
At the moment, the `ScriptLoadRequest` structure hold all the fields which are
loaded, and used before executing JavaScript code. Then, the `ScriptLoadRequest`
is not guaranteed to out-live the first execution.
Therefore, we have to move fields out of the `ScriptLoadRequest` such that they
can later be used by any caching mechanism. The `LoadedScript` is the closest
existing structure which exists which fit the description.
This patch moves fields out of the ScriptLoadRequest into the `LoadedScript`,
which already has a `LoadedScript` field.
The `LoadedScript` field is initialized sooner, when the `ScriptLoadRequest` is
created, to be subsituted later by a real cache implementation. At the moment
the function `ScriptLoadRequest::NoCacheEntryFound` is used as a placeholder to
change the state of the `ScriptLoadRequest` from `CheckingCache` to `Fetching`.
Existing initializations are replaced by assertions to fail in debug build if
the current patch does not reproduce the expected state properly.
The `LoadedScript` get fields such as the source text, the text length, the
bytecode buffer (which also contains SRI), and the offset at which the bytecode
starts within the bytecode buffer. As these fields are no longer reachable by
name, multiple accessors are added to work-around the issue. Using this as an
opportunity to add extra assertions as part of these accessors.
A new class named `LoadedScriptDelegate` is added to re-add, by inheritance, all
the accessors which used to be part of `ScriptLoadRequest` as methods which are
delegating to the field which is holding the `LoadedScript`. This class is using
templates to avoid virtual inheritance which might hinder inlining, especially
since `ScriptLoadRequest` cannot be made final, as `ModuleLoadRequest` extends
it.
The `ScriptFetchOptions` structure is moved to its own file to solve C++ include
issues.
Differential Revision: https://phabricator.services.mozilla.com/D163615
Original patch by mccr8.
At least for the cycle collector, the purpose of calling unmark gray when
accessing a JS field of a C++ object is to avoid creating references from a
black object to a gray object. However, this particular code is writing
undefined, so that should not be a danger.
This particular code is by its nature dealing with GC things that are gray and
may be about to be GCed, so calling unmark grey can waste a tremendous amount
of time. On a profile of collecting a JS-heavy page, I was seeing 20% of the
100ms CC being spent on it.
The patch uses unbarrieredGet in ModuleScript::UnlinkModuleRecord and adds a
new API to clear a module record's private value without checking whether
associated objects are gray.
Differential Revision: https://phabricator.services.mozilla.com/D165202
Jonatan Klemets