• Milad Farazmand's avatar
    PPC/s390: Reland "[compiler] Optionally apply an offset to stack checks" · 05918654
    Milad Farazmand authored
    Port b875f466
    
    Original Commit Message:
    
        This is a reland of 4a16305b
    
        The original CL adjust only one part of the stack check, namely the
        comparison of the stack pointer against the stack limit in generated code.
        There is a second part: Runtime::kStackGuard repeats this check to
        distinguish between a stack overflow and an interrupt request.
    
        This second part in runtime must apply the offset just like in generated
        code. It is implemented in this reland by the StackCheckOffset operator
        and a new StackGuardWithGap runtime function.
    
        Original change's description:
        > [compiler] Optionally apply an offset to stack checks
        >
        > The motivation behind this change is that the frame size of an optimized
        > function and its unoptimized version may differ, and deoptimization
        > may thus trigger a stack overflow. The solution implemented in this CL
        > is to optionally apply an offset to the stack check s.t. the check
        > becomes 'sp - offset > limit'. The offset is applied to stack checks at
        > function-entry, and is set to the difference between the optimized and
        > unoptimized frame size.
        >
        > A caveat: OSR may not be fully handled by this fix since we've already
        > passed the function-entry stack check. A possible solution would be to
        > *not* skip creation of function-entry stack checks for inlinees.
        >
        > This CL: 1. annotates stack check nodes with the stack check kind, where
        > kind is one of {function-entry,iteration-body,unknown}. 2. potentially
        > allocates a temporary register to store the result of the 'sp - offset'
        > in instruction selection (and switches input registers to 'unique'
        > mode). 3. Applies the offset in code generation.
        >
        > Drive-by: Add src/compiler/globals.h for compiler-specific globals.
        >
        > Bug: v8:9534,chromium:1000887
        > Change-Id: I257191c4a4978ccb60cfa5805ef421f30f0e9826
        > Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1762521
        > Commit-Queue: Jakob Gruber <jgruber@chromium.org>
        > Reviewed-by: Georg Neis <neis@chromium.org>
        > Cr-Commit-Position: refs/heads/master@{#63701}
    
    R=jgruber@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
    BUG=
    LOG=N
    
    Change-Id: I37bf1d9157a96a5d3538108703f2d7469a11bffe
    Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1890535Reviewed-by: 's avatarJunliang Yan <jyan@ca.ibm.com>
    Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
    Cr-Commit-Position: refs/heads/master@{#64652}
    05918654
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