[PATCH] D16440: [ThinLTO] Link in only necessary DICompileUnit operands

Tue Feb 23 09:14:26 PST 2016

FYI, I had a quick look at the big merged file.  I walked back from one of
the unresolved types:
```
!"_ZTSN3JSC6ParserINS_5LexerItEEEE" => used by !DIDerivedType(pointer) // via baseType:
!DIDerivedType() => used by !DISubroutineType() // via types:
!DISubroutineType() => used by !DISubprogram() // via type:
// note: isDefinition: false
!DISubprogram(isDefinition: false) => used by !DICompositeType(class) // via elements:
// note: class has identifier:, but not listed directly in a compile unit!
!DICompositeType(class) => used by !DICompositeType(enum) // via: scope:
!DICompositeType(enum) => used by !DICompileUnit() // via: retainedTypes:
```

The weird thing I noticed: there was a class in the chain that had an identifier
but was also not directly listed in retained types.

Maybe this will help someone come up with a reproducer?

> On 2016-Feb-22, at 20:24, Mehdi Amini <mehdi.amini at apple.com> wrote:
> 
> I didn't expect any miracle from you :)
> My intention was just mentioning that the patch shouldn't be committed as there is a known bug, and I obviously will try to give a reasonably small repro ASAP.
> 
> -- 
> Mehdi
> 
>> On Feb 22, 2016, at 7:39 PM, Teresa Johnson <tejohnson at google.com> wrote:
>> 
>> Unfortunately without seeing how the types were referenced in the original module I may not be able to deduce why they weren't pulled in. But go ahead and send me the IR after importing in the meantime and I will see what I can figure out.
>> 
>> 
>> On Mon, Feb 22, 2016 at 6:02 PM, Mehdi Amini <mehdi.amini at apple.com> wrote:
>> Unfortunately IIRC it involved 800 files, and I don't have them. I need to reproduce and it'll take some time. I can send you the IR *after* importing (the broken module) if it can help (not sure).
>> 
>> -- 
>> Mehdi
>> 
>> 
>> 
>>> On Feb 22, 2016, at 5:52 PM, Teresa Johnson <tejohnson at google.com> wrote:
>>> 
>>> Can you give me a test case to reproduce, or at least the IR for the module we're importing from (where these presumably came from) and which function(s) were imported?
>>> 
>>> Thanks,
>>> Teresa
>>> 
>>> On Mon, Feb 22, 2016 at 5:37 PM, Mehdi Amini <mehdi.amini at apple.com> wrote:
>>> We still have an issue with this patch, when compiling this with thinlto and debug info: https://github.com/adobe/webkit/blob/master/Source/WebCore/inspector/InspectorRuntimeAgent.cpp
>>> 
>>> I haven't had time to narrow it unfortunately, it seems that "baseType" for some DIDerivedType entries are not present.
>>> What we see is a broken LLVM Module straight after the FunctionImporter. The output looks like this:
>>> 
>>> unresolved type ref
>>> !"_ZTSN3JSC14ScopeLabelInfoE"
>>> !121713 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !"_ZTSN3JSC14ScopeLabelInfoE", size: 64, align: 64)
>>> unresolved type ref
>>> !"_ZTSN3JSC15DeclarationTypeE"
>>> !121577 = !DISubroutineType(types: !121578)
>>> unresolved type ref
>>> !"_ZTSN3JSC17AssignmentContextE"
>>> !121580 = !DISubroutineType(types: !121581)
>>> unresolved type ref
>>> !"_ZTSN3JSC17DestructuringKindE"
>>> !121577 = !DISubroutineType(types: !121578)
>>> unresolved type ref
>>> !"_ZTSN3JSC21DeclarationImportTypeE"
>>> !121606 = !DISubroutineType(types: !121607)
>>> unresolved type ref
>>> !"_ZTSN3JSC23SourceProviderCacheItemE"
>>> !121621 = !DIDerivedType(tag: DW_TAG_const_type, baseType: !"_ZTSN3JSC23SourceProviderCacheItemE")
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerIhEEE10LexerStateE"
>>> !121743 = !DISubroutineType(types: !121744)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerIhEEE15AutoPopScopeRefE"
>>> !121600 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !"_ZTSN3JSC6ParserINS_5LexerIhEEE15AutoPopScopeRefE", size: 64, align: 64)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerIhEEE20ExpressionErrorClassE"
>>> !121571 = !DISubroutineType(types: !121572)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerIhEEE23AutoCleanupLexicalScopeE"
>>> !121604 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !"_ZTSN3JSC6ParserINS_5LexerIhEEE23AutoCleanupLexicalScopeE", size: 64, align: 64)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerIhEEE25ExpressionErrorClassifierE"
>>> !121535 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !"_ZTSN3JSC6ParserINS_5LexerIhEEE25ExpressionErrorClassifierE", size: 64, align: 64)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerIhEEE9SavePointE"
>>> !121751 = !DISubroutineType(types: !121752)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerItEEE10LexerStateE"
>>> !122000 = !DISubroutineType(types: !122001)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerItEEE15AutoPopScopeRefE"
>>> !121866 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !"_ZTSN3JSC6ParserINS_5LexerItEEE15AutoPopScopeRefE", size: 64, align: 64)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerItEEE20ExpressionErrorClassE"
>>> !121838 = !DISubroutineType(types: !121839)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerItEEE23AutoCleanupLexicalScopeE"
>>> !121870 = !DIDerivedType(tag: DW_TAG_reference_type, baseType: !"_ZTSN3JSC6ParserINS_5LexerItEEE23AutoCleanupLexicalScopeE", size: 64, align: 64)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerItEEE25ExpressionErrorClassifierE"
>>> !121803 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !"_ZTSN3JSC6ParserINS_5LexerItEEE25ExpressionErrorClassifierE", size: 64, align: 64)
>>> unresolved type ref
>>> !"_ZTSN3JSC6ParserINS_5LexerItEEE9SavePointE"
>>> !122008 = !DISubroutineType(types: !122009)
>>> unresolved type ref
>>> !"_ZTSN3JSC9ScopeNodeE"
>>> !121635 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !"_ZTSN3JSC9ScopeNodeE", size: 64, align: 64)
>>> 
>>> 
>>> --
>>> Mehdi
>>> 
>>> 
>>> > On Feb 22, 2016, at 2:20 PM, Teresa Johnson <tejohnson at google.com> wrote:
>>> >
>>> > tejohnson updated this revision to Diff 48732.
>>> > tejohnson added a comment.
>>> >
>>> > Handle a null MD passed to MapMetadata to address problem reported by
>>> > ahatanak.
>>> >
>>> >
>>> > http://reviews.llvm.org/D16440
>>> >
>>> > Files:
>>> >  include/llvm/Linker/IRMover.h
>>> >  lib/Linker/IRMover.cpp
>>> >  lib/Linker/LinkModules.cpp
>>> >  lib/Transforms/Utils/ValueMapper.cpp
>>> >  test/Linker/thinlto_funcimport_debug.ll
>>> >  test/Transforms/FunctionImport/Inputs/funcimport_debug.ll
>>> >  test/Transforms/FunctionImport/funcimport_debug.ll
>>> >
>>> > <D16440.48732.patch>
>>> 
>>> 
>>> 
>>> 
>>> -- 
>>> Teresa Johnson |	 Software Engineer |	 tejohnson at google.com |	 408-460-2413
>> 
>> 
>> 
>> 
>> -- 
>> Teresa Johnson |	 Software Engineer |	 tejohnson at google.com |	 408-460-2413
> 