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Andreas Haas authored
With this CL it is guaranteed that every time after AllocatedStackSpace allocates a full page, this page also gets touched. Background: On Windows it is required to touch every new memory page on the stack before adding another memory page. This is implemented in {AllocateStackSpace}. This was implemented so far by repeatedly allocating a new page, followed by touching the new page. The last allocation, which may has up to the size of a page, did not get touched anymore, with the assumption that allocated stack space will be used before new stack space gets allocated. However, this assumption is wrong. In Liftoff, the whole stack space that is needed for a function gets allocated in the beginning of the function. This stack space may only be used for spills though, and the spilling may only happen after the first function call in the function. In this case the callee function will write to its own stack frame before the stack frame of the caller gets used. As written above, the last allocation does not get touched anymore. In the case that this is a full memory page, this can mean that a full memory page gets skipped without getting touched. With this CL it is guaranteed that the last allocation is always smaller than one page, and therefore it is impossible to skip a full page without touching it as long as there are no two calls to {AllocateStackSpace} without a {push} in between. Bug: v8:12063 Change-Id: If0bb41212e882beb926aac538001b02f179fc03e Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3168276 Commit-Queue: Andreas Haas <ahaas@chromium.org> Reviewed-by: Clemens Backes <clemensb@chromium.org> Cr-Commit-Position: refs/heads/main@{#76915}
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