aeda4157d4
6 Commits
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Seth Brenith
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386ed8a9a0 |
Update postmortem tools to use unsigned compressed pointers
The tests were already passing because they happened to use objects allocated in the lower half of the heap reservation, but this small change should make behavior more consistent. Change-Id: Ib6be3123d347234f4771c213f2209bfe6e19c569 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1860332 Reviewed-by: Igor Sheludko <ishell@chromium.org> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com> Cr-Commit-Position: refs/heads/master@{#64294} |
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Seth Brenith
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1d3c4975be |
[tools] Use instance types of known Maps in v8_debug_helper
If we can read an object's Map pointer but not any data from the Map itself, we may still be able to accurately describe the object's type if the Map pointer matches one of the known Maps from the snapshot. GetObjectProperties uses that data in one of two ways: - If it is sure that the Map pointer matches a known Map, then it uses the type from that Map and continues as if it read the type normally. - If the Map pointer is at the right offset within a heap page to match a known Map, but the caller didn't provide the addresses of the first pages in Map space or read-only space, then the type of that Map is just a guess and gets returned in a separate array. This gives the caller the opportunity to present guessed types to the user, and perhaps call again using the guessed type as the type hint. Bug: v8:9376 Change-Id: I187f67b77e76699863a14534a9d635b79f654124 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1787986 Commit-Queue: Seth Brenith <seth.brenith@microsoft.com> Reviewed-by: Jakob Gruber <jgruber@chromium.org> Reviewed-by: Michael Achenbach <machenbach@chromium.org> Reviewed-by: Tobias Tebbi <tebbi@chromium.org> Cr-Commit-Position: refs/heads/master@{#63908} |
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Seth Brenith
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2ccca6c5ac |
[tools][torque] Include string values in GetObjectProperties responses
This change provides a quick way to see string contents in postmortem debugging sessions, without digging through a (possibly very large, in the case of ConsString) tree of properties. As well as being convenient for inspecting String objects, this functionality will also be necessary for displaying property names on JSReceiver objects. In order to support custom behaviors for specific classes, this change extends the existing generated debug reader classes with a visitor pattern. Bug: v8:9376 Change-Id: I70eab9ea4e74ca0fab39bf5998d6a602716a4202 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1771939 Reviewed-by: Tobias Tebbi <tebbi@chromium.org> Commit-Queue: Seth Brenith <seth.brenith@microsoft.com> Cr-Commit-Position: refs/heads/master@{#63485} |
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Seth Brenith
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0921e8f28b |
Reland "Add postmortem debugging helper library"
This is a reland of
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Zhi An Ng
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6747e3a186 |
Revert "Add postmortem debugging helper library"
This reverts commit
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Seth Brenith
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517ab73fd7 |
Add postmortem debugging helper library
This change begins to implement the functionality described in https://docs.google.com/document/d/1evHnb1uLlSbvHAAsmOXyc25x3uh1DjgNa8u1RHvwVhk/edit# for investigating V8 state in crash dumps. This change adds a new library, v8_debug_helper, for providing platform- agnostic assistance with postmortem debugging. This library can be used by extensions built for debuggers such as WinDbg or lldb. Its public API is described by debug-helper.h; currently the only method it exposes is GetObjectProperties, but we'd like to add more functionality over time. The API surface is restricted to plain C-style structs and pointers, so that it's easy to link from a debugger extension built with a different toolchain. This change also adds a new cctest file to exercise some basic interaction with the new library. The API function GetObjectProperties takes an object pointer (which could be compressed, or weak, or a SMI), and returns a string description of the object and a list of properties the object contains. For now, the list of properties is entirely based on Torque object definitions, but we expect to add custom properties in future updates so that it can be easier to make sense of complex data structures such as dictionaries. GetObjectProperties does several things that are intended to generate somewhat useful results even in cases where memory may be corrupt or unavailable: - The caller may optionally provide a type string which will be used if the memory for the object's Map is inaccessible. - All object pointers are compared against the list of known objects generated by mkgrokdump. The caller may optionally provide the pointers for the first pages of various heap spaces, to avoid spurious matches. If those pointers are not provided, then any matches are prefixed with "maybe" in the resulting description string, such as "maybe UndefinedValue (0x4288000341 <Oddball>)". Bug: v8:9376 Change-Id: Iebf3cc2dea3133c7811bcefcdf38d9458b02fded Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1628012 Commit-Queue: Seth Brenith <seth.brenith@microsoft.com> Reviewed-by: Yang Guo <yangguo@chromium.org> Reviewed-by: Michael Stanton <mvstanton@chromium.org> Cr-Commit-Position: refs/heads/master@{#62882} |