[PATCH] D42095: [WebAssembly] Symbol changes #3: Make Clang object file tables match LLD output. NFC.

[Sam Clegg via Phabricator via llvm-commits]

sbc100 added inline comments.


================
Comment at: test/MC/WebAssembly/weak-alias.ll:197
+; CHECK-NEXT:           Value:           16
+; CHECK-NEXT:         Content:         '01000000'
+; CHECK-NEXT:   - Type:            CUSTOM
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sbc100 wrote:
> ncw wrote:
> > sbc100 wrote:
> > > How as this change generated a new data segment?  I guess maybe it was zero before so now it was elided?  
> > > 
> > > It looks to me like we really want to two different function addresses here for the address of the function itself and the address of the weak alias.  Its not until link time that these two things become the same thing.  Maybe it doesn't really matter as long as the linker can distinguish them, but it makes sense to be that there would be two different function addresses in this object file.
> > Ah, the test data before was skipping the section - see the "CHECK" in the original file, rather than "CHECK-NEXT". I thought it was useful to expand the test to assert on the section that was being skipped; it was odd that previously it was deliberately not examining the final segment.
> > 
> > "It's not until link time that they become the same thing" -> but the table in the object file is linked. The "provisional" values that are used for relocations in the object file are a preview of the values that would get written out. I think it makes sense to use the same rules for writing out provisional values as we do for writing out the actual values in LLD. Hence we don't put the exact same function twice in the table - there's really no point. Seeing a function appear multiple times in the table doesn't make the output any easier to read.
> But for intermediate output such as this (or the lld -r) we are still waiting for the a potential strong version of the symbol, so the weak alias and the function in points too are still district (both here and in lld -r).   
> 
Hmm.. maybe i'll expand this test expectation now as a separate change to make this change more explicit.


Repository:
  rL LLVM

https://reviews.llvm.org/D42095