[+v8-dev -chromium-dev] On Wed, Aug 15, 2018 at 2:42 PM Christian Biesinger <cbiesin...@chromium.org> wrote:
> You may be better off asking on the V8 mailing list: > https://groups.google.com/group/v8-dev Yup, redirecting there. > Although I don't know how close I got, this is my latest attempt: > That looks fine. That said, these are changes to SharedFunctionInfo, whereas in your mail, you talk about adding a field to JSFunction. Which did you do? The patch looks fine, the error is surprising. Adding a field at the end of an object shouldn't perturb other fields at its beginning... Are you sure you haven't made any other changes? > > > > in shared-function-info.h: > > ...... > > DECL_INT_ACCESSORS(flags2) > > ...... > > DECL_BOOLEAN_ACCESSORS(is_foo) > > ...... > > // Layout description. > > #define SHARED_FUNCTION_INFO_FIELDS(V) \ > > /* Pointer fields. */ \ > > V(kStartOfPointerFieldsOffset, 0) \ > > V(kFunctionDataOffset, kPointerSize) \ > > V(kNameOrScopeInfoOffset, kPointerSize) \ > > V(kOuterScopeInfoOrFeedbackMetadataOffset, kPointerSize) \ > > V(kScriptOffset, kPointerSize) \ > > V(kFunctionIdentifierOrDebugInfoOffset, kPointerSize) \ > > V(kEndOfPointerFieldsOffset, 0) \ > > /* Raw data fields. */ \ > > V(kUniqueIdOffset, kUniqueIdFieldSize) \ > > V(kLengthOffset, kUInt16Size) \ > > V(kFormalParameterCountOffset, kUInt16Size) \ > > V(kExpectedNofPropertiesOffset, kUInt16Size) \ > > V(kFunctionTokenOffsetOffset, kUInt16Size) \ > > V(kFlagsOffset, kInt32Size) \ > > V(kFlagsOffset2, kInt32Size) \ > > /* Total size. */ \ > > V(kSize, 0) > > ...... > > // Bit positions in |flags2| > > #define FLAGS_BIT_FIELDS2(V, _) \ > > V(IsFooBit, bool, 1, _) > > DEFINE_BIT_FIELDS(FLAGS_BIT_FIELDS2) > > #undef FLAGS_BIT_FIELDS2 > > > > in shared-fucntion-info-inl.h > > BIT_FIELD_ACCESSORS(SharedFunctionInfo, flags2, is_foo, > > SharedFunctionInfo::IsFooBit) > > > > Also I exposed proper setter/getter(s) in v8.h and api.cc. However, I > keep getting errors while loading pages: > > abort: The function_data field should be a BytecodeArray on interpreter > entry > > Received signal 11 SEGV_MAPERR 0009ffffffff > > #0 0x7fd8eff58d5d base::debug::StackTrace::StackTrace() > > #1 0x7fd8efc3cdec base::debug::StackTrace::StackTrace() > > #2 0x7fd8eff587b4 base::debug::(anonymous > namespace)::StackDumpSignalHandler() > > #3 0x7fd8d0fbe390 <unknown> > > #4 0x7fd8dad4068f v8::internal::AbstractCode::SourcePosition() > > #5 0x7fd8da67c4ce v8::internal::JavaScriptFrame::Print() > > #6 0x7fd8da770f81 v8::internal::Isolate::PrintStack() > > #7 0x7fd8da772b37 v8::internal::Isolate::PrintStack() > > #8 0x7fd8da9a2c16 v8::internal::__RT_impl_Runtime_Abort() > > #9 0x7fd8da9a28df v8::internal::Runtime_Abort() > > > > I know I'm now playing with some executable HeapObject at runtime so I > need to make sure its layout is valid. Having this said, it remains unclear > to me what I should do exactly to adjust relevant bits to ensure the > JSFunction object pertains its recognizable structure. Could anyone please > provide a little input on this? Thanks so much in advance! > > > > On Tuesday, August 14, 2018 at 5:21:32 PM UTC-7, stzh...@gmail.com > wrote: > >> > >> Hi all, > >> > >> I've been trying hard to add a custom bool flag in > v8::internal::JSFunction. It feels like classes like JSFunction are not > designed for adding things this way because I ran into all kinds of errors > and/or DCHECK failures. > >> > >> Methods I've tried so far: (i) adding bool variables directly to > v8/src/objects.h and v8/src/objects-inl.h directly ---> object layout gets > garbled so it's no longer valid executable JSFunction; (ii) adding fields > via DECL_BOOLEAN_ACCESSORS and other macros ---> various bits seem to need > adjustment, otherwise fails DCHECKs. Without detailed documentation, I'm > basically in a haze in terms of how should I re-calculate those bits. > >> > >> Any tip or working example of adding such a field? Existing examples in > the code look pretty confusing as they don't seem to have a clear > documentation/usage (per my understanding of Chromium internals, which is > quite basic...). Thanks a lot! > >> > >> Best, > >> - Z > > > > -- > > -- > > Chromium Developers mailing list: chromium-...@chromium.org > > View archives, change email options, or unsubscribe: > > http://groups.google.com/a/chromium.org/group/chromium-dev > > --- > > You received this message because you are subscribed to the Google > Groups "Chromium-dev" group. > > To view this discussion on the web visit > https://groups.google.com/a/chromium.org/d/msgid/chromium-dev/84f9fc7b-320e-4fb4-9d8c-314e274e057e%40chromium.org > . > > -- > -- > Chromium Developers mailing list: chromium-...@chromium.org > View archives, change email options, or unsubscribe: > http://groups.google.com/a/chromium.org/group/chromium-dev > --- > You received this message because you are subscribed to the Google Groups > "Chromium-dev" group. > To view this discussion on the web visit > https://groups.google.com/a/chromium.org/d/msgid/chromium-dev/CAPTJ0XEemft9VzTgJ_ssfoWEzp6TEfCHx9vGjmeDHz%2BaQjmFWA%40mail.gmail.com > . > > -- -- v8-dev mailing list v8-dev@googlegroups.com http://groups.google.com/group/v8-dev --- You received this message because you are subscribed to the Google Groups "v8-dev" group. 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