r347205 - [FileManager] getFile(open=true) after getFile(open=false) should open the file.

Nico Weber via cfe-commits cfe-commits at lists.llvm.org
Wed Jan 23 13:26:46 PST 2019


For completeness, in case the construction isn't clear, here's a full repro
of the symptom.

$ cat pch.cc
$ cat pch.h
#include "foo.h"
$ rm bar/foo.h
$ for i in {1..300}; do echo '#include "foo'$i'.h"' >> bar/foo.h; done
$ for i in {1..300}; do touch bar/foo$i.h; done
$ cat client.cc
#include "bar/foo.h"
$ for i in {1..300}; do echo '#include "bar/foo'$i'.h"' >> client.cc; done

With today's trunk, on macOS:

Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Ycpch.h
/FIpch.h pch.cc  /Ibar
Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Yupch.h
/FIpch.h client.cc /Ibar
client.cc(253,10):  fatal error: 'bar/foo252.h' file not found
#include "bar/foo252.h"
         ^~~~~~~~~~~~~~
1 error generated.

This works fine with this patch undone.

On Wed, Jan 23, 2019 at 2:55 PM Nico Weber <thakis at chromium.org> wrote:

> This might finally be a repro!
>
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ ls bar
> foo.h foo2.h
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ type foo.h
> -bash: type: foo.h: not found
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ ls bar
> foo.h foo2.h
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat bar/foo.h
> #include "foo2.h"
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat bar/foo2.h
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat pch.h
> #include "foo.h"
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat pch.cc
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat client.cc
> #include "bar/foo.h"
> #include "bar/foo2.h"
>
> #include "foo3.h"
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Ycpch.h
> /FIpch.h pch.cc  /Ibar
> stat pch.cc 1
> opened pch.cc
> closing pch.cc
> stat ./pch.h 1
> opened ./pch.h
> closing ./pch.h
> stat ./foo.h 1
> stat bar/foo.h 1
> opened bar/foo.h
> closing bar/foo.h
> stat bar/foo2.h 1
> opened bar/foo2.h
> closing bar/foo2.h
> stat pch.cc 1
> opened pch.cc
> stat pch.pch 1
> opened pch.pch
> closing pch.pch
> stat /Users/thakis/src/llvm-mono-2/bar/foo2.h 0
> stat /Users/thakis/src/llvm-mono-2/bar/foo.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
> closing /Users/thakis/src/llvm-mono-2/pch.cc
> stat ./pch.h 1
> opened ./pch.h
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Yupch.h
> /FIpch.h client.cc
> stat client.cc 1
> opened client.cc
> stat pch.pch 1
> opened pch.pch
> closing pch.pch
> stat /Users/thakis/src/llvm-mono-2/bar/foo2.h 0
> stat /Users/thakis/src/llvm-mono-2/bar/foo.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
> closing client.cc
> stat ./pch.h 1
> opened ./pch.h
> stat ./bar/foo.h 1
> opened ./bar/foo.h
> closing ./bar/foo.h
> stat /Users/thakis/src/llvm-mono-2/bar/foo2.h 1
> opened /Users/thakis/src/llvm-mono-2/bar/foo2.h
> closing /Users/thakis/src/llvm-mono-2/bar/foo2.h
> stat ./bar/foo2.h 1
> opened ./bar/foo2.h
> stat ./foo3.h 1
> opened ./foo3.h
> closing ./foo3.h
>
>
> Note how ./bar/foo2.h is opened in the 4th-to-last line but never closed.
> For comparision, with your patch reverted:
>
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Ycpch.h
> /FIpch.h pch.cc  /Ibar
> stat pch.cc 1
> opened pch.cc
> closing pch.cc
> stat ./pch.h 1
> opened ./pch.h
> closing ./pch.h
> stat ./foo.h 1
> stat bar/foo.h 1
> opened bar/foo.h
> closing bar/foo.h
> stat bar/foo2.h 1
> opened bar/foo2.h
> closing bar/foo2.h
> stat pch.cc 1
> opened pch.cc
> stat pch.pch 1
> opened pch.pch
> closing pch.pch
> stat /Users/thakis/src/llvm-mono-2/bar/foo2.h 0
> stat /Users/thakis/src/llvm-mono-2/bar/foo.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
> closing /Users/thakis/src/llvm-mono-2/pch.cc
> stat ./pch.h 1
> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Yupch.h
> /FIpch.h client.cc
> stat client.cc 1
> opened client.cc
> stat pch.pch 1
> opened pch.pch
> closing pch.pch
> stat /Users/thakis/src/llvm-mono-2/bar/foo2.h 0
> stat /Users/thakis/src/llvm-mono-2/bar/foo.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.h 0
> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
> closing client.cc
> stat ./pch.h 1
> stat ./bar/foo.h 1
> stat ./bar/foo2.h 1
> stat ./foo3.h 1
> opened ./foo3.h
> closing ./foo3.h
>
> On Wed, Jan 23, 2019 at 2:21 PM Nico Weber <thakis at chromium.org> wrote:
>
>> On Wed, Jan 23, 2019 at 2:17 PM Nico Weber <thakis at chromium.org> wrote:
>>
>>> Here's what I think is a repro:
>>>
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat foo.h
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat foo2.h
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat pch.h
>>> #include "foo.h"
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat pch.cc
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ cat client.cc
>>> #include "foo2.h"
>>> #include "foo.h"
>>>
>>> #include "foo2.h"
>>> #include "foo.h"
>>>
>>> Then just build pch.cc with a pch file, and then use it (you can do this
>>> on any OS; you could also use the gcc style driver if you prefer it).
>>>
>>> The following output is with your change reverted, I added
>>>
>>> fprintf(stderr, "stat %s %d\n", Filename.str().c_str(), openFile);
>>>
>>> right before the call to getStatValue() in getFile, and
>>>
>>> if (openFile) fprintf(stderr, "opened %s\n", Filename.str().c_str());
>>>   UFE.File = std::move(F);
>>>
>>> at the very bottom of that function, and changed getBufferForFile() to
>>> have
>>>
>>>     if (ShouldCloseOpenFile) {
>>> fprintf(stderr, "closing %s\n", Entry->getName().str().c_str());
>>>       Entry->closeFile();
>>> }
>>>
>>>
>>> The output is:
>>>
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Ycpch.h
>>> /FIpch.h pch.cc
>>> stat pch.cc 1
>>> opened pch.cc
>>> closing pch.cc
>>> stat ./pch.h 1
>>> opened ./pch.h
>>> closing ./pch.h
>>> stat ./foo.h 1
>>> opened ./foo.h
>>> closing ./foo.h
>>> stat pch.cc 1
>>> opened pch.cc
>>> stat pch.pch 1
>>> opened pch.pch
>>> closing pch.pch
>>> stat /Users/thakis/src/llvm-mono-2/foo.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
>>> closing /Users/thakis/src/llvm-mono-2/pch.cc
>>> stat ./pch.h 1
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Yupch.h
>>> /FIpch.h client.cc
>>> stat client.cc 1
>>> opened client.cc
>>> stat pch.pch 1
>>> opened pch.pch
>>> closing pch.pch
>>> stat /Users/thakis/src/llvm-mono-2/foo.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
>>> closing client.cc
>>> stat ./pch.h 1
>>> stat ./foo2.h 1
>>> opened ./foo2.h
>>> closing ./foo2.h
>>> stat ./foo.h 1
>>>
>>>
>>> Note how foo.h at the end is stat'd with openFile = 1, but we don't keep
>>> that file handle around.
>>>
>>> Now with your patch applied, where put the
>>>
>>> if (openFile) fprintf(stderr, "opened %s\n", Filename.str().c_str());
>>>     UFE.File = std::move(F);
>>>
>>> print in the block you moved up.
>>>
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Ycpch.h
>>> /FIpch.h pch.cc
>>> stat pch.cc 1
>>> opened pch.cc
>>> closing pch.cc
>>> stat ./pch.h 1
>>> opened ./pch.h
>>> closing ./pch.h
>>> stat ./foo.h 1
>>> opened ./foo.h
>>> closing ./foo.h
>>> stat pch.cc 1
>>> opened pch.cc
>>> stat pch.pch 1
>>> opened pch.pch
>>> closing pch.pch
>>> stat /Users/thakis/src/llvm-mono-2/foo.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
>>> closing /Users/thakis/src/llvm-mono-2/pch.cc
>>> stat ./pch.h 1
>>> opened ./pch.h
>>> Nicos-MacBook-Pro:llvm-mono-2 thakis$ out/gn/bin/clang-cl /c /Yupch.h
>>> /FIpch.h client.cc
>>> stat client.cc 1
>>> opened client.cc
>>> stat pch.pch 1
>>> opened pch.pch
>>> closing pch.pch
>>> stat /Users/thakis/src/llvm-mono-2/foo.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.h 0
>>> stat /Users/thakis/src/llvm-mono-2/pch.cc 0
>>> closing client.cc
>>> stat ./pch.h 1
>>> opened ./pch.h
>>> stat ./foo2.h 1
>>> opened ./foo2.h
>>> closing ./foo2.h
>>> stat ./foo.h 1
>>> opened ./foo.h
>>> closing ./foo.h
>>>
>>>
>>> Notice how pch.pch gets opened twice but never closed in the version
>>> with your patch.
>>>
>>
>> Sorry, I mean pch.h. But that's probably just from the /FI flag. While
>> this is an example of a file that's opened and not closed with your patch,
>> it'd be nice to have a repro that shows this from an #include line, not
>> from an /FI flag. Let me look at this a bit more. Sorry for the noise.
>>
>>
>>> I think this is enough to show that your patch is introducing
>>> assumptions made by clang's PCH code. Even though the issue isn't
>>> understood in detail, this is imho enough to revert and fix and debug
>>> async, unless you're able to fix very quickly.
>>>
>>>
>>>
>>> On Wed, Jan 23, 2019 at 1:23 PM Nico Weber <thakis at chromium.org> wrote:
>>>
>>>> The way things worked before your patch is that getFile() calls for
>>>> headers that are loaded from a PCH file hit the early-ish return in
>>>>
>>>>   if (UFE.isValid()) { // Already have an entry with this inode, return
>>>> it.
>>>>
>>>> The first stack I posted (with ReadControlBlock() in it) populates
>>>> this UniqueRealFiles cache, and then getFile() for includes in a pch when
>>>> called from the preprocessor just return "early", at least before the file
>>>> is opened. (Stack for that:
>>>>
>>>> (lldb) bt
>>>> * thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint
>>>> 3.1
>>>>   * frame #0: 0x000000010005a2cf
>>>> clang-cl`clang::FileManager::getFile(this=0x000000011200a190,
>>>> Filename=(Data =
>>>> "../../third_party/blink/renderer/core/layout/api/third_party/skia/include/core/SkPoint3.h/paint/third_party/skia/include/core/SkPoint3.hܲ?\x01",
>>>> Length = 89), openFile=true, CacheFailure=true) at FileManager.cpp:198
>>>>     frame #1: 0x0000000102ca1cb2
>>>> clang-cl`clang::HeaderSearch::getFileAndSuggestModule(this=0x000000011282e600,
>>>> FileName=(Data =
>>>> "../../third_party/blink/renderer/core/layout/api/third_party/skia/include/core/SkPoint3.h/paint/third_party/skia/include/core/SkPoint3.hܲ?\x01",
>>>> Length = 89), IncludeLoc=(ID = 4980551), Dir=0x000000011071e500,
>>>> IsSystemHeaderDir=false, RequestingModule=0x0000000000000000,
>>>> SuggestedModule=0x00007fff5fbf9020) at HeaderSearch.cpp:313
>>>>     frame #2: 0x0000000102ca37aa
>>>> clang-cl`clang::HeaderSearch::LookupFile(this=0x000000011282e600,
>>>> Filename=(Data = "third_party/skia/include/core/SkPoint3.h", Length = 40),
>>>> IncludeLoc=(ID = 4980551), isAngled=false, FromDir=0x0000000000000000,
>>>> CurDir=0x00007fff5fbf9848, Includers=ArrayRef<std::__1::pair<const
>>>> clang::FileEntry *, const clang::DirectoryEntry *> > @ 0x00007fff5fbf7c78,
>>>> SearchPath=0x00007fff5fbf9438, RelativePath=0x00007fff5fbf9028,
>>>> RequestingModule=0x0000000000000000, SuggestedModule=0x00007fff5fbf9020,
>>>> IsMapped=0x00007fff5fbf9857, SkipCache=false, BuildSystemModule=false) at
>>>> HeaderSearch.cpp:756
>>>>     frame #3: 0x0000000102d01898
>>>> clang-cl`clang::Preprocessor::LookupFile(this=0x000000011282f618,
>>>> FilenameLoc=(ID = 4980551), Filename=(Data =
>>>> "third_party/skia/include/core/SkPoint3.h", Length = 40), isAngled=false,
>>>> FromDir=0x0000000000000000, FromFile=0x0000000000000000,
>>>> CurDir=0x00007fff5fbf9848, SearchPath=0x00007fff5fbf9438,
>>>> RelativePath=0x00007fff5fbf9028, SuggestedModule=0x00007fff5fbf9020,
>>>> IsMapped=0x00007fff5fbf9857, SkipCache=false) at PPDirectives.cpp:740
>>>>     frame #4: 0x0000000102d033c4
>>>> clang-cl`clang::Preprocessor::HandleIncludeDirective(this=0x000000011282f618,
>>>> HashLoc=(ID = 4980542), IncludeTok=0x000000011180a810,
>>>> LookupFrom=0x0000000000000000, LookupFromFile=0x0000000000000000,
>>>> isImport=false) at PPDirectives.cpp:1773
>>>>     frame #5: 0x0000000102d05e3a
>>>> clang-cl`clang::Preprocessor::HandleDirective(this=0x000000011282f618,
>>>> Result=0x000000011180a810) at PPDirectives.cpp:942
>>>>     frame #6: 0x0000000102cbff1f
>>>> clang-cl`clang::Lexer::LexTokenInternal(this=0x000000011bc567a0,
>>>> Result=0x000000011180a810, TokAtPhysicalStartOfLine=true) at Lexer.cpp:3931
>>>>     frame #7: 0x0000000102cbc1b8
>>>> clang-cl`clang::Lexer::Lex(this=0x000000011bc567a0,
>>>> Result=0x000000011180a810) at Lexer.cpp:3152
>>>>     frame #8: 0x0000000102d54dcb
>>>> clang-cl`clang::Preprocessor::Lex(this=0x000000011282f618,
>>>> Result=0x000000011180a810) at Preprocessor.cpp:868
>>>>     frame #9: 0x0000000102f235f9
>>>> clang-cl`clang::Parser::ConsumeBrace(this=0x000000011180a800) at
>>>> Parser.h:563
>>>>     frame #10: 0x0000000102f2a21a
>>>> clang-cl`clang::BalancedDelimiterTracker::consumeClose(this=0x00007fff5fbfa560)
>>>> at RAIIObjectsForParser.h:429
>>>>     frame #11: 0x0000000102e788e5
>>>> clang-cl`clang::Parser::ParseInnerNamespace(this=0x000000011180a800,
>>>> InnerNSs=0x00007fff5fbfa6e0, index=0, InlineLoc=0x00007fff5fbfa7a0,
>>>> attrs=0x00007fff5fbfa6b8, Tracker=0x00007fff5fbfa560) at
>>>> ParseDeclCXX.cpp:250
>>>>     frame #12: 0x0000000102e77dd6
>>>> clang-cl`clang::Parser::ParseNamespace(this=0x000000011180a800,
>>>> Context=FileContext, DeclEnd=0x00007fff5fbfaa70, InlineLoc=(ID = 0)) at
>>>> ParseDeclCXX.cpp:223
>>>>     frame #13: 0x0000000102e5af29
>>>> clang-cl`clang::Parser::ParseDeclaration(this=0x000000011180a800,
>>>> Context=FileContext, DeclEnd=0x00007fff5fbfaa70, attrs=0x00007fff5fbfac40)
>>>> at ParseDecl.cpp:1714
>>>>     frame #14: 0x0000000102f25dc3
>>>> clang-cl`clang::Parser::ParseExternalDeclaration(this=0x000000011180a800,
>>>> attrs=0x00007fff5fbfac40, DS=0x0000000000000000) at Parser.cpp:788
>>>>     frame #15: 0x0000000102f24f06
>>>> clang-cl`clang::Parser::ParseTopLevelDecl(this=0x000000011180a800,
>>>> Result=0x00007fff5fbfad78) at Parser.cpp:609
>>>>     frame #16: 0x0000000102e4a076
>>>> clang-cl`clang::ParseAST(S=0x00000001118fb600, PrintStats=true,
>>>> SkipFunctionBodies=false) at ParseAST.cpp:156
>>>>     frame #17: 0x0000000100add312
>>>> clang-cl`clang::ASTFrontendAction::ExecuteAction(this=0x0000000112007eb0)
>>>> at FrontendAction.cpp:1035
>>>>     frame #18: 0x00000001004f6cbd
>>>> clang-cl`clang::CodeGenAction::ExecuteAction(this=0x0000000112007eb0) at
>>>> CodeGenAction.cpp:1047
>>>>     frame #19: 0x0000000100adc920
>>>> clang-cl`clang::FrontendAction::Execute(this=0x0000000112007eb0) at
>>>> FrontendAction.cpp:934
>>>>     frame #20: 0x0000000100a4ce4e
>>>> clang-cl`clang::CompilerInstance::ExecuteAction(this=0x0000000112005f70,
>>>> Act=0x0000000112007eb0) at CompilerInstance.cpp:954
>>>>     frame #21: 0x0000000100b5c25f
>>>> clang-cl`clang::ExecuteCompilerInvocation(Clang=0x0000000112005f70) at
>>>> ExecuteCompilerInvocation.cpp:267
>>>>     frame #22: 0x0000000100001ab9 clang-cl`cc1_main(Argv=ArrayRef<const
>>>> char *> @ 0x00007fff5fbfb4c8,
>>>> Argv0="../../../../llvm-mono-2/out/gn/bin/clang-cl",
>>>> MainAddr=0x0000000100028100) at cc1_main.cpp:218
>>>>     frame #23: 0x000000010002998f
>>>> clang-cl`ExecuteCC1Tool(argv=ArrayRef<const char *> @ 0x00007fff5fbfba78,
>>>> Tool=(Data = "", Length = 0)) at driver.cpp:309
>>>>     frame #24: 0x0000000100028a71 clang-cl`main(argc_=409,
>>>> argv_=0x00007fff5fbfd170) at driver.cpp:381
>>>>     frame #25: 0x00007fffb015c235 libdyld.dylib`start + 1
>>>>
>>>> ).
>>>>
>>>>
>>>> After your patch, we open the file before that cache check, and then
>>>> open way more files, and don't the ones from the PCH for some reason.
>>>> Closing is normally happening in through
>>>>
>>>> Preprocessor::HandleIncludeDirective() ->
>>>> Preprocessor::EnterSourceFile() -> SourceManager::getBuffer() ->
>>>> ContentCache::getBuffer()
>>>> -> FileManager::getBufferForFile(ShouldCloseOpenFile)
>>>>
>>>> but apparently that's not getting called for headers from PCH files.
>>>>
>>>> On Wed, Jan 23, 2019 at 12:38 PM Nico Weber <thakis at chromium.org>
>>>> wrote:
>>>>
>>>>> Stacks for getFile() from PCH files look like so:
>>>>>
>>>>> (lldb) bt
>>>>> * thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint
>>>>> 1.1
>>>>>   * frame #0: 0x000000010005a1fb
>>>>> clang-cl`clang::FileManager::getFile(this=0x00000001106111f0,
>>>>> Filename=(Data =
>>>>> "/Users/thakis/src/chrome/src/out/gnwin/../../third_party/skia/include/core/SkPoint3.h",
>>>>> Length = 85), openFile=false, CacheFailure=true) at FileManager.cpp:187
>>>>>     frame #1: 0x0000000103c44b2e
>>>>> clang-cl`clang::ASTReader::getInputFile(this=0x000000011104c200,
>>>>> F=0x000000011104fc00, ID=3, Complain=true) at ASTReader.cpp:2120
>>>>>     frame #2: 0x0000000103c5173b
>>>>> clang-cl`clang::ASTReader::ReadControlBlock(this=0x000000011104c200,
>>>>> F=0x000000011104fc00, Loaded=0x00007fff5fbfa130,
>>>>> ImportedBy=0x0000000000000000, ClientLoadCapabilities=0) at
>>>>> ASTReader.cpp:2398
>>>>>     frame #3: 0x0000000103c5381b
>>>>> clang-cl`clang::ASTReader::ReadASTCore(this=0x000000011104c200,
>>>>> FileName=(Data =
>>>>> "obj/third_party/blink/renderer/core/layout/layout_cc.pch", Length = 56),
>>>>> Type=MK_PCH, ImportLoc=(ID = 0), ImportedBy=0x0000000000000000,
>>>>> Loaded=0x00007fff5fbfa130, ExpectedSize=0, ExpectedModTime=0,
>>>>> ExpectedSignature=ASTFileSignature @ 0x00007fff5fbf9d58,
>>>>> ClientLoadCapabilities=0) at ASTReader.cpp:4208
>>>>>     frame #4: 0x0000000103c5fe95
>>>>> clang-cl`clang::ASTReader::ReadAST(this=0x000000011104c200, FileName=(Data
>>>>> = "obj/third_party/blink/renderer/core/layout/layout_cc.pch", Length = 56),
>>>>> Type=MK_PCH, ImportLoc=(ID = 0), ClientLoadCapabilities=0,
>>>>> Imported=0x0000000000000000) at ASTReader.cpp:3883
>>>>>     frame #5: 0x0000000100a49542
>>>>> clang-cl`clang::CompilerInstance::createPCHExternalASTSource(Path=(Data =
>>>>> "obj/third_party/blink/renderer/core/layout/layout_cc.pch", Length = 56),
>>>>> Sysroot=(Data = "/", Length = 1), DisablePCHValidation=false,
>>>>> AllowPCHWithCompilerErrors=false, PP=0x0000000111037e18,
>>>>> Context=0x0000000111042200, PCHContainerRdr=0x000000011060d2b0,
>>>>> Extensions=ArrayRef<std::__1::shared_ptr<clang::ModuleFileExtension> > @
>>>>> 0x00007fff5fbfa430, DependencyFile=0x0000000000000000,
>>>>> DependencyCollectors=ArrayRef<std::__1::shared_ptr<clang::DependencyCollector>
>>>>> > @ 0x00007fff5fbfa448, DeserializationListener=0x0000000000000000,
>>>>> OwnDeserializationListener=false, Preamble=false,
>>>>> UseGlobalModuleIndex=true) at CompilerInstance.cpp:532
>>>>>     frame #6: 0x0000000100a4909b
>>>>> clang-cl`clang::CompilerInstance::createPCHExternalASTSource(this=0x000000011060d000,
>>>>> Path=(Data = "obj/third_party/blink/renderer/core/layout/layout_cc.pch",
>>>>> Length = 56), DisablePCHValidation=false, AllowPCHWithCompilerErrors=false,
>>>>> DeserializationListener=0x0000000000000000,
>>>>> OwnDeserializationListener=false) at CompilerInstance.cpp:490
>>>>>     frame #7: 0x0000000100ada301
>>>>> clang-cl`clang::FrontendAction::BeginSourceFile(this=0x000000011060eee0,
>>>>> CI=0x000000011060d000, RealInput=0x0000000110614a60) at
>>>>> FrontendAction.cpp:859
>>>>>     frame #8: 0x0000000100a4cdf8
>>>>> clang-cl`clang::CompilerInstance::ExecuteAction(this=0x000000011060d000,
>>>>> Act=0x000000011060eee0) at CompilerInstance.cpp:953
>>>>>     frame #9: 0x0000000100b5c21f
>>>>> clang-cl`clang::ExecuteCompilerInvocation(Clang=0x000000011060d000) at
>>>>> ExecuteCompilerInvocation.cpp:267
>>>>>     frame #10: 0x0000000100001ac9
>>>>> clang-cl`cc1_main(Argv=ArrayRef<const char *> @ 0x00007fff5fbfb4c8,
>>>>> Argv0="../../../../llvm-mono-2/out/gn/bin/clang-cl",
>>>>> MainAddr=0x0000000100028110) at cc1_main.cpp:218
>>>>>     frame #11: 0x000000010002999f
>>>>> clang-cl`ExecuteCC1Tool(argv=ArrayRef<const char *> @ 0x00007fff5fbfba78,
>>>>> Tool=(Data = "", Length = 0)) at driver.cpp:309
>>>>>     frame #12: 0x0000000100028a81 clang-cl`main(argc_=409,
>>>>> argv_=0x00007fff5fbfd170) at driver.cpp:381
>>>>>     frame #13: 0x00007fffb015c235 libdyld.dylib`start + 1
>>>>>
>>>>> (lldb) bt
>>>>> * thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint
>>>>> 1.1
>>>>>   * frame #0: 0x000000010005a1fb
>>>>> clang-cl`clang::FileManager::getFile(this=0x00000001106111f0,
>>>>> Filename=(Data =
>>>>> "/Users/thakis/src/chrome/src/out/gnwin/../../third_party/skia/include/core/SkPoint3.h",
>>>>> Length = 85), openFile=false, CacheFailure=true) at FileManager.cpp:187
>>>>>     frame #1: 0x0000000103c476e3
>>>>> clang-cl`clang::serialization::reader::HeaderFileInfoTrait::EqualKey(this=0x00007fff5fbf5f80,
>>>>> Key=0x00007fff5fbf6068)::$_1::operator()(clang::serialization::reader::HeaderFileInfoTrait::internal_key_type
>>>>> const&) const at ASTReader.cpp:1723
>>>>>     frame #2: 0x0000000103c4759f
>>>>> clang-cl`clang::serialization::reader::HeaderFileInfoTrait::EqualKey(this=0x0000000113a16c88,
>>>>> a=0x00007fff5fbf6068, b=0x00007fff5fbf6138) at ASTReader.cpp:1726
>>>>>     frame #3: 0x0000000103cd5c1e
>>>>> clang-cl`llvm::OnDiskChainedHashTable<clang::serialization::reader::HeaderFileInfoTrait>::find_hashed(this=0x0000000113a16c70,
>>>>> IKey=0x00007fff5fbf6138, KeyHash=986574196, InfoPtr=0x0000000113a16c88) at
>>>>> OnDiskHashTable.h:390
>>>>>     frame #4: 0x0000000103cd59b8
>>>>> clang-cl`llvm::OnDiskChainedHashTable<clang::serialization::reader::HeaderFileInfoTrait>::find(this=0x0000000113a16c70,
>>>>> EKey=0x00007fff5fbf6538, InfoPtr=0x0000000000000000) at
>>>>> OnDiskHashTable.h:345
>>>>>     frame #5: 0x0000000103cd58b9 clang-cl`(anonymous
>>>>> namespace)::HeaderFileInfoVisitor::operator(this=0x00007fff5fbf6538,
>>>>> M=0x000000011104fc00)(clang::serialization::ModuleFile&) at
>>>>> ASTReader.cpp:5683
>>>>>     frame #6: 0x0000000103cd5850 clang-cl`bool llvm::function_ref<bool
>>>>> (clang::serialization::ModuleFile&)>::callback_fn<(anonymous
>>>>> namespace)::HeaderFileInfoVisitor>(callable=140734799766840,
>>>>> params=0x000000011104fc00) at STLExtras.h:125
>>>>>     frame #7: 0x0000000103e338cc clang-cl`llvm::function_ref<bool
>>>>> (clang::serialization::ModuleFile&)>::operator(this=0x00007fff5fbf64a0,
>>>>> params=0x000000011104fc00)(clang::serialization::ModuleFile&) const at
>>>>> STLExtras.h:142
>>>>>     frame #8: 0x0000000103e33507
>>>>> clang-cl`clang::serialization::ModuleManager::visit(this=0x000000011104c298,
>>>>> Visitor=function_ref<bool (clang::serialization::ModuleFile &)> @
>>>>> 0x00007fff5fbf64a0, ModuleFilesHit=0x0000000000000000)>,
>>>>> llvm::SmallPtrSetImpl<clang::serialization::ModuleFile*>*) at
>>>>> ModuleManager.cpp:411
>>>>>     frame #9: 0x0000000103c69ade
>>>>> clang-cl`clang::ASTReader::GetHeaderFileInfo(this=0x000000011104c200,
>>>>> FE=0x0000000113a00030) at ASTReader.cpp:5698
>>>>>     frame #10: 0x0000000103c69d03 clang-cl`non-virtual thunk to
>>>>> clang::ASTReader::GetHeaderFileInfo(this=0x000000011104c200,
>>>>> FE=0x0000000113a00030) at ASTReader.cpp:0
>>>>>     frame #11: 0x0000000102ca607c
>>>>> clang-cl`clang::HeaderSearch::getExistingFileInfo(this=0x0000000111036e00,
>>>>> FE=0x0000000113a00030, WantExternal=true) const at HeaderSearch.cpp:1140
>>>>>     frame #12: 0x0000000102ca6faf
>>>>> clang-cl`clang::HeaderSearch::findModuleForHeader(this=0x0000000111036e00,
>>>>> File=0x0000000113a00030, AllowTextual=true) const at HeaderSearch.cpp:1334
>>>>>     frame #13: 0x0000000102ca700a
>>>>> clang-cl`suggestModule(HS=0x0000000111036e00, File=0x0000000113a00030,
>>>>> RequestingModule=0x0000000000000000, SuggestedModule=0x00007fff5fbf9020) at
>>>>> HeaderSearch.cpp:1343
>>>>>     frame #14: 0x0000000102ca1dd2
>>>>> clang-cl`clang::HeaderSearch::findUsableModuleForHeader(this=0x0000000111036e00,
>>>>> File=0x0000000113a00030, Root=0x00000001106126d0,
>>>>> RequestingModule=0x0000000000000000, SuggestedModule=0x00007fff5fbf9020,
>>>>> IsSystemHeaderDir=false) at HeaderSearch.cpp:1367
>>>>>     frame #15: 0x0000000102ca1cee
>>>>> clang-cl`clang::HeaderSearch::getFileAndSuggestModule(this=0x0000000111036e00,
>>>>> FileName=(Data = "../../third_party/skia/include/core/SkPoint3.h", Length =
>>>>> 46), IncludeLoc=(ID = 4980551), Dir=0x00000001106126d0,
>>>>> IsSystemHeaderDir=false, RequestingModule=0x0000000000000000,
>>>>> SuggestedModule=0x00007fff5fbf9020) at HeaderSearch.cpp:318
>>>>>     frame #16: 0x0000000102ca20ad
>>>>> clang-cl`clang::DirectoryLookup::LookupFile(this=0x000000011060f1e0,
>>>>> Filename=0x00007fff5fbf7c20, HS=0x0000000111036e00, IncludeLoc=(ID =
>>>>> 4980551), SearchPath=0x00007fff5fbf9438, RelativePath=0x00007fff5fbf9028,
>>>>> RequestingModule=0x0000000000000000, SuggestedModule=0x00007fff5fbf9020,
>>>>> InUserSpecifiedSystemFramework=0x00007fff5fbf763f,
>>>>> HasBeenMapped=0x00007fff5fbf763e, MappedName=0x00007fff5fbf7640) const at
>>>>> HeaderSearch.cpp:357
>>>>>     frame #17: 0x0000000102ca3e15
>>>>> clang-cl`clang::HeaderSearch::LookupFile(this=0x0000000111036e00,
>>>>> Filename=(Data = "third_party/skia/include/core/SkPoint3.h", Length = 40),
>>>>> IncludeLoc=(ID = 4980551), isAngled=false, FromDir=0x0000000000000000,
>>>>> CurDir=0x00007fff5fbf9848, Includers=ArrayRef<std::__1::pair<const
>>>>> clang::FileEntry *, const clang::DirectoryEntry *> > @ 0x00007fff5fbf7c78,
>>>>> SearchPath=0x00007fff5fbf9438, RelativePath=0x00007fff5fbf9028,
>>>>> RequestingModule=0x0000000000000000, SuggestedModule=0x00007fff5fbf9020,
>>>>> IsMapped=0x00007fff5fbf9857, SkipCache=false, BuildSystemModule=false) at
>>>>> HeaderSearch.cpp:854
>>>>>     frame #18: 0x0000000102d01858
>>>>> clang-cl`clang::Preprocessor::LookupFile(this=0x0000000111037e18,
>>>>> FilenameLoc=(ID = 4980551), Filename=(Data =
>>>>> "third_party/skia/include/core/SkPoint3.h", Length = 40), isAngled=false,
>>>>> FromDir=0x0000000000000000, FromFile=0x0000000000000000,
>>>>> CurDir=0x00007fff5fbf9848, SearchPath=0x00007fff5fbf9438,
>>>>> RelativePath=0x00007fff5fbf9028, SuggestedModule=0x00007fff5fbf9020,
>>>>> IsMapped=0x00007fff5fbf9857, SkipCache=false) at PPDirectives.cpp:740
>>>>>     frame #19: 0x0000000102d03384
>>>>> clang-cl`clang::Preprocessor::HandleIncludeDirective(this=0x0000000111037e18,
>>>>> HashLoc=(ID = 4980542), IncludeTok=0x000000011080ac10,
>>>>> LookupFrom=0x0000000000000000, LookupFromFile=0x0000000000000000,
>>>>> isImport=false) at PPDirectives.cpp:1773
>>>>>     frame #20: 0x0000000102d05dfa
>>>>> clang-cl`clang::Preprocessor::HandleDirective(this=0x0000000111037e18,
>>>>> Result=0x000000011080ac10) at PPDirectives.cpp:942
>>>>>     frame #21: 0x0000000102cbfedf
>>>>> clang-cl`clang::Lexer::LexTokenInternal(this=0x000000011a6f1430,
>>>>> Result=0x000000011080ac10, TokAtPhysicalStartOfLine=true) at Lexer.cpp:3931
>>>>>     frame #22: 0x0000000102cbc178
>>>>> clang-cl`clang::Lexer::Lex(this=0x000000011a6f1430,
>>>>> Result=0x000000011080ac10) at Lexer.cpp:3152
>>>>>     frame #23: 0x0000000102d54d8b
>>>>> clang-cl`clang::Preprocessor::Lex(this=0x0000000111037e18,
>>>>> Result=0x000000011080ac10) at Preprocessor.cpp:868
>>>>>     frame #24: 0x0000000102f235b9
>>>>> clang-cl`clang::Parser::ConsumeBrace(this=0x000000011080ac00) at
>>>>> Parser.h:563
>>>>>     frame #25: 0x0000000102f2a1da
>>>>> clang-cl`clang::BalancedDelimiterTracker::consumeClose(this=0x00007fff5fbfa560)
>>>>> at RAIIObjectsForParser.h:429
>>>>>     frame #26: 0x0000000102e788a5
>>>>> clang-cl`clang::Parser::ParseInnerNamespace(this=0x000000011080ac00,
>>>>> InnerNSs=0x00007fff5fbfa6e0, index=0, InlineLoc=0x00007fff5fbfa7a0,
>>>>> attrs=0x00007fff5fbfa6b8, Tracker=0x00007fff5fbfa560) at
>>>>> ParseDeclCXX.cpp:250
>>>>>     frame #27: 0x0000000102e77d96
>>>>> clang-cl`clang::Parser::ParseNamespace(this=0x000000011080ac00,
>>>>> Context=FileContext, DeclEnd=0x00007fff5fbfaa70, InlineLoc=(ID = 0)) at
>>>>> ParseDeclCXX.cpp:223
>>>>>     frame #28: 0x0000000102e5aee9
>>>>> clang-cl`clang::Parser::ParseDeclaration(this=0x000000011080ac00,
>>>>> Context=FileContext, DeclEnd=0x00007fff5fbfaa70, attrs=0x00007fff5fbfac40)
>>>>> at ParseDecl.cpp:1714
>>>>>     frame #29: 0x0000000102f25d83
>>>>> clang-cl`clang::Parser::ParseExternalDeclaration(this=0x000000011080ac00,
>>>>> attrs=0x00007fff5fbfac40, DS=0x0000000000000000) at Parser.cpp:788
>>>>>     frame #30: 0x0000000102f24ec6
>>>>> clang-cl`clang::Parser::ParseTopLevelDecl(this=0x000000011080ac00,
>>>>> Result=0x00007fff5fbfad78) at Parser.cpp:609
>>>>>     frame #31: 0x0000000102e4a036
>>>>> clang-cl`clang::ParseAST(S=0x00000001108fba00, PrintStats=true,
>>>>> SkipFunctionBodies=false) at ParseAST.cpp:156
>>>>>     frame #32: 0x0000000100add2d2
>>>>> clang-cl`clang::ASTFrontendAction::ExecuteAction(this=0x000000011060eee0)
>>>>> at FrontendAction.cpp:1035
>>>>>     frame #33: 0x00000001004f6c7d
>>>>> clang-cl`clang::CodeGenAction::ExecuteAction(this=0x000000011060eee0) at
>>>>> CodeGenAction.cpp:1047
>>>>>     frame #34: 0x0000000100adc8e0
>>>>> clang-cl`clang::FrontendAction::Execute(this=0x000000011060eee0) at
>>>>> FrontendAction.cpp:934
>>>>>     frame #35: 0x0000000100a4ce0e
>>>>> clang-cl`clang::CompilerInstance::ExecuteAction(this=0x000000011060d000,
>>>>> Act=0x000000011060eee0) at CompilerInstance.cpp:954
>>>>>     frame #36: 0x0000000100b5c21f
>>>>> clang-cl`clang::ExecuteCompilerInvocation(Clang=0x000000011060d000) at
>>>>> ExecuteCompilerInvocation.cpp:267
>>>>>     frame #37: 0x0000000100001ac9
>>>>> clang-cl`cc1_main(Argv=ArrayRef<const char *> @ 0x00007fff5fbfb4c8,
>>>>> Argv0="../../../../llvm-mono-2/out/gn/bin/clang-cl",
>>>>> MainAddr=0x0000000100028110) at cc1_main.cpp:218
>>>>>     frame #38: 0x000000010002999f
>>>>> clang-cl`ExecuteCC1Tool(argv=ArrayRef<const char *> @ 0x00007fff5fbfba78,
>>>>> Tool=(Data = "", Length = 0)) at driver.cpp:309
>>>>>     frame #39: 0x0000000100028a81 clang-cl`main(argc_=409,
>>>>> argv_=0x00007fff5fbfd170) at driver.cpp:381
>>>>>     frame #40: 0x00007fffb015c235 libdyld.dylib`start + 1
>>>>>
>>>>>
>>>>> For regular includes they look like so:
>>>>>
>>>>> (lldb) bt
>>>>> * thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint
>>>>> 1.1
>>>>>   * frame #0: 0x0000000100059d29
>>>>> clang-cl`clang::FileManager::getStatValue(this=0x0000000110611270,
>>>>> Path=(Data =
>>>>> "../../third_party/blink/renderer/platform/scheduler/public/scheduling_lifecycle_state.h",
>>>>> Length = 87), Data=0x00007fff5fbf6640, isFile=true, F=0x00007fff5fbf6680)
>>>>> at FileManager.cpp:465
>>>>>     frame #1: 0x000000010005a471
>>>>> clang-cl`clang::FileManager::getFile(this=0x0000000110611270,
>>>>> Filename=(Data =
>>>>> "../../third_party/blink/renderer/platform/scheduler/public/scheduling_lifecycle_state.h",
>>>>> Length = 87), openFile=true, CacheFailure=true) at FileManager.cpp:230
>>>>>     frame #2: 0x0000000102ca1ca2
>>>>> clang-cl`clang::HeaderSearch::getFileAndSuggestModule(this=0x0000000111036e00,
>>>>> FileName=(Data =
>>>>> "../../third_party/blink/renderer/platform/scheduler/public/scheduling_lifecycle_state.h",
>>>>> Length = 87), IncludeLoc=(ID = 9004850), Dir=0x0000000110502730,
>>>>> IsSystemHeaderDir=false, RequestingModule=0x0000000000000000,
>>>>> SuggestedModule=0x00007fff5fbf9030) at HeaderSearch.cpp:313
>>>>>     frame #3: 0x0000000102ca20dd
>>>>> clang-cl`clang::DirectoryLookup::LookupFile(this=0x0000000110503850,
>>>>> Filename=0x00007fff5fbf7c30, HS=0x0000000111036e00, IncludeLoc=(ID =
>>>>> 9004850), SearchPath=0x00007fff5fbf9448, RelativePath=0x00007fff5fbf9038,
>>>>> RequestingModule=0x0000000000000000, SuggestedModule=0x00007fff5fbf9030,
>>>>> InUserSpecifiedSystemFramework=0x00007fff5fbf764f,
>>>>> HasBeenMapped=0x00007fff5fbf764e, MappedName=0x00007fff5fbf7650) const at
>>>>> HeaderSearch.cpp:357
>>>>>     frame #4: 0x0000000102ca3e45
>>>>> clang-cl`clang::HeaderSearch::LookupFile(this=0x0000000111036e00,
>>>>> Filename=(Data =
>>>>> "third_party/blink/renderer/platform/scheduler/public/scheduling_lifecycle_state.h",
>>>>> Length = 81), IncludeLoc=(ID = 9004850), isAngled=false,
>>>>> FromDir=0x0000000000000000, CurDir=0x00007fff5fbf9858,
>>>>> Includers=ArrayRef<std::__1::pair<const clang::FileEntry *, const
>>>>> clang::DirectoryEntry *> > @ 0x00007fff5fbf7c88,
>>>>> SearchPath=0x00007fff5fbf9448, RelativePath=0x00007fff5fbf9038,
>>>>> RequestingModule=0x0000000000000000, SuggestedModule=0x00007fff5fbf9030,
>>>>> IsMapped=0x00007fff5fbf9867, SkipCache=false, BuildSystemModule=false) at
>>>>> HeaderSearch.cpp:854
>>>>>     frame #5: 0x0000000102d01888
>>>>> clang-cl`clang::Preprocessor::LookupFile(this=0x0000000111037e18,
>>>>> FilenameLoc=(ID = 9004850), Filename=(Data =
>>>>> "third_party/blink/renderer/platform/scheduler/public/scheduling_lifecycle_state.h",
>>>>> Length = 81), isAngled=false, FromDir=0x0000000000000000,
>>>>> FromFile=0x0000000000000000, CurDir=0x00007fff5fbf9858,
>>>>> SearchPath=0x00007fff5fbf9448, RelativePath=0x00007fff5fbf9038,
>>>>> SuggestedModule=0x00007fff5fbf9030, IsMapped=0x00007fff5fbf9867,
>>>>> SkipCache=false) at PPDirectives.cpp:740
>>>>>     frame #6: 0x0000000102d033b4
>>>>> clang-cl`clang::Preprocessor::HandleIncludeDirective(this=0x0000000111037e18,
>>>>> HashLoc=(ID = 9004841), IncludeTok=0x0000000115068810,
>>>>> LookupFrom=0x0000000000000000, LookupFromFile=0x0000000000000000,
>>>>> isImport=false) at PPDirectives.cpp:1773
>>>>>     frame #7: 0x0000000102d05e2a
>>>>> clang-cl`clang::Preprocessor::HandleDirective(this=0x0000000111037e18,
>>>>> Result=0x0000000115068810) at PPDirectives.cpp:942
>>>>>     frame #8: 0x0000000102cbff0f
>>>>> clang-cl`clang::Lexer::LexTokenInternal(this=0x000000011d98b010,
>>>>> Result=0x0000000115068810, TokAtPhysicalStartOfLine=true) at Lexer.cpp:3931
>>>>>     frame #9: 0x0000000102cbc1a8
>>>>> clang-cl`clang::Lexer::Lex(this=0x000000011d98b010,
>>>>> Result=0x0000000115068810) at Lexer.cpp:3152
>>>>>     frame #10: 0x0000000102d54dbb
>>>>> clang-cl`clang::Preprocessor::Lex(this=0x0000000111037e18,
>>>>> Result=0x0000000115068810) at Preprocessor.cpp:868
>>>>>     frame #11: 0x0000000102f235e9
>>>>> clang-cl`clang::Parser::ConsumeBrace(this=0x0000000115068800) at
>>>>> Parser.h:563
>>>>>     frame #12: 0x0000000102f2a20a
>>>>> clang-cl`clang::BalancedDelimiterTracker::consumeClose(this=0x00007fff5fbfa570)
>>>>> at RAIIObjectsForParser.h:429
>>>>>     frame #13: 0x0000000102e788d5
>>>>> clang-cl`clang::Parser::ParseInnerNamespace(this=0x0000000115068800,
>>>>> InnerNSs=0x00007fff5fbfa6f0, index=0, InlineLoc=0x00007fff5fbfa7b0,
>>>>> attrs=0x00007fff5fbfa6c8, Tracker=0x00007fff5fbfa570) at
>>>>> ParseDeclCXX.cpp:250
>>>>>     frame #14: 0x0000000102e77dc6
>>>>> clang-cl`clang::Parser::ParseNamespace(this=0x0000000115068800,
>>>>> Context=FileContext, DeclEnd=0x00007fff5fbfaa80, InlineLoc=(ID = 0)) at
>>>>> ParseDeclCXX.cpp:223
>>>>>     frame #15: 0x0000000102e5af19
>>>>> clang-cl`clang::Parser::ParseDeclaration(this=0x0000000115068800,
>>>>> Context=FileContext, DeclEnd=0x00007fff5fbfaa80, attrs=0x00007fff5fbfac50)
>>>>> at ParseDecl.cpp:1714
>>>>>     frame #16: 0x0000000102f25db3
>>>>> clang-cl`clang::Parser::ParseExternalDeclaration(this=0x0000000115068800,
>>>>> attrs=0x00007fff5fbfac50, DS=0x0000000000000000) at Parser.cpp:788
>>>>>     frame #17: 0x0000000102f24ef6
>>>>> clang-cl`clang::Parser::ParseTopLevelDecl(this=0x0000000115068800,
>>>>> Result=0x00007fff5fbfad88) at Parser.cpp:609
>>>>>     frame #18: 0x0000000102e4a066
>>>>> clang-cl`clang::ParseAST(S=0x0000000115061a00, PrintStats=false,
>>>>> SkipFunctionBodies=false) at ParseAST.cpp:156
>>>>>     frame #19: 0x0000000100add302
>>>>> clang-cl`clang::ASTFrontendAction::ExecuteAction(this=0x000000011060ef90)
>>>>> at FrontendAction.cpp:1035
>>>>>     frame #20: 0x00000001004f6cad
>>>>> clang-cl`clang::CodeGenAction::ExecuteAction(this=0x000000011060ef90) at
>>>>> CodeGenAction.cpp:1047
>>>>>     frame #21: 0x0000000100adc910
>>>>> clang-cl`clang::FrontendAction::Execute(this=0x000000011060ef90) at
>>>>> FrontendAction.cpp:934
>>>>>     frame #22: 0x0000000100a4ce3e
>>>>> clang-cl`clang::CompilerInstance::ExecuteAction(this=0x000000011060d050,
>>>>> Act=0x000000011060ef90) at CompilerInstance.cpp:954
>>>>>     frame #23: 0x0000000100b5c24f
>>>>> clang-cl`clang::ExecuteCompilerInvocation(Clang=0x000000011060d050) at
>>>>> ExecuteCompilerInvocation.cpp:267
>>>>>     frame #24: 0x0000000100001b19
>>>>> clang-cl`cc1_main(Argv=ArrayRef<const char *> @ 0x00007fff5fbfb4d8,
>>>>> Argv0="../../../../llvm-mono-2/out/gn/bin/clang-cl",
>>>>> MainAddr=0x0000000100028160) at cc1_main.cpp:218
>>>>>     frame #25: 0x00000001000299ef
>>>>> clang-cl`ExecuteCC1Tool(argv=ArrayRef<const char *> @ 0x00007fff5fbfba88,
>>>>> Tool=(Data = "", Length = 0)) at driver.cpp:309
>>>>>     frame #26: 0x0000000100028ad1 clang-cl`main(argc_=408,
>>>>> argv_=0x00007fff5fbfd188) at driver.cpp:381
>>>>>     frame #27: 0x00007fffb015c235 libdyld.dylib`start + 1
>>>>>     frame #28: 0x00007fffb015c235 libdyld.dylib`start + 1
>>>>>
>>>>>
>>>>>
>>>>> On Wed, Jan 23, 2019 at 12:10 PM Sam McCall <sammccall at google.com>
>>>>> wrote:
>>>>>
>>>>>> Thanks! given that we don't see an earlier stat, I guess these files
>>>>>> were being treated as virtual (file metadata deserialized from PCH).
>>>>>> Previously despite the open=true these never actually got opened, and that
>>>>>> worked fine.
>>>>>>
>>>>>> I'm away from my computer but will verify later tonight or in the
>>>>>> morning (CET) and try to find a fix. If it's not obvious, we should revert
>>>>>> the patch at least on the release branch.
>>>>>>
>>>>>> A stack trace at the relevant breakpoint might well be useful - can't
>>>>>> remember if there are lots of entry points here.
>>>>>>
>>>>>> Cheers, Sam
>>>>>>
>>>>>> On Wed, Jan 23, 2019, 16:38 Nico Weber <thakis at chromium.org wrote:
>>>>>>
>>>>>>> With your patch reverted locally, at the same breakpoint I instead
>>>>>>> get
>>>>>>>
>>>>>>> $ lsof -p 95842 | wc -l
>>>>>>>       94
>>>>>>>
>>>>>>> So your patch seems to increase number of open file handles by ~260%.
>>>>>>>
>>>>>>> On Wed, Jan 23, 2019 at 10:27 AM Nico Weber <thakis at chromium.org>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> On Wed, Jan 23, 2019 at 9:54 AM Sam McCall <sammccall at google.com>
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>> (Email is better than IRC if that's OK - I don't know this code
>>>>>>>>> that well so it takes me a while).
>>>>>>>>>
>>>>>>>>> Thanks, that's definitely interesting and not what I expected. I
>>>>>>>>> thought every call sequence r347205 changed the behavior of would have
>>>>>>>>> resulted in two calls to getStatValue().
>>>>>>>>> I guess the "pch"/"main" output is printed before the
>>>>>>>>> corresponding lines in run.sh?
>>>>>>>>>
>>>>>>>>
>>>>>>>> Correct.
>>>>>>>>
>>>>>>>>
>>>>>>>>> Weird that we don't get any output from building the PCH, but I
>>>>>>>>> don't know well how PCH builds work.
>>>>>>>>>
>>>>>>>>> > It looks like FS->getCurrentWorkingDirectory() is set
>>>>>>>>> yet FileSystemOpts.WorkingDir.empty() is also true. Is that expected?
>>>>>>>>> I think so. The FileManager and the VFS each have their own
>>>>>>>>> concept of working directory, I guess for historical reasons.
>>>>>>>>> Making use of the VFS one but not the FileManager one seems
>>>>>>>>> reasonable.
>>>>>>>>>
>>>>>>>>> So the weirdness is that FileSystemStatCache::get() is returning
>>>>>>>>> true (i.e. file doesn't exist), when the file does exist.
>>>>>>>>> Possibilities:
>>>>>>>>> 1) we're serving this result from the FileSystemStatCache (and
>>>>>>>>> maybe it's being poisoned in a PCH-related way somehow). Except as far as I
>>>>>>>>> can tell, FileSystemStatCache is always null (FileManager::setStateCache
>>>>>>>>> has no callers).
>>>>>>>>> 2) the FS.openFileForRead call failed (ultimately ::open, if FS is
>>>>>>>>> the real FS)
>>>>>>>>> 3) the OwnedFile->status() call failed (ultimately ::fstat)
>>>>>>>>> 4) I'm misreading the code somehow
>>>>>>>>>
>>>>>>>>
>>>>>>>> ::open() fails with errno == 24, EMFILE.
>>>>>>>>
>>>>>>>> This log statement here:
>>>>>>>>
>>>>>>>> diff --git a/clang/lib/Basic/FileSystemStatCache.cpp
>>>>>>>> b/clang/lib/Basic/FileSystemStatCache.cpp
>>>>>>>> index d29ebb750fc..63fc4780237 100644
>>>>>>>> --- a/clang/lib/Basic/FileSystemStatCache.cpp
>>>>>>>> +++ b/clang/lib/Basic/FileSystemStatCache.cpp
>>>>>>>> @@ -70,9 +70,13 @@ bool FileSystemStatCache::get(StringRef Path,
>>>>>>>> FileData &Data, bool isFile,
>>>>>>>>      //
>>>>>>>>      // Because of this, check to see if the file exists with
>>>>>>>> 'open'.  If the
>>>>>>>>      // open succeeds, use fstat to get the stat info.
>>>>>>>> -    auto OwnedFile = FS.openFileForRead(Path);
>>>>>>>> +    llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>> OwnedFile =
>>>>>>>> +        FS.openFileForRead(Path);
>>>>>>>>
>>>>>>>>      if (!OwnedFile) {
>>>>>>>> +if (Path.endswith("scheduling_lifecycle_state.h")) {
>>>>>>>> +fprintf(stderr, "hmm failed %s\n",
>>>>>>>> OwnedFile.getError().message().c_str());
>>>>>>>> +}
>>>>>>>>        // If the open fails, our "stat" fails.
>>>>>>>>        R = CacheMissing;
>>>>>>>>      } else {
>>>>>>>>
>>>>>>>>
>>>>>>>> causes clang to print "hmm failed Too many open files". That path
>>>>>>>> should maybe check if `OwnedFile.getError().value() == EMFILE &&
>>>>>>>> OwnedFile.getError().category() == std::generic_category()` on mac and
>>>>>>>> abort or diag or something more visible.
>>>>>>>>
>>>>>>>> `ulimit -n` on macOS is pretty small -- do you see how your patch
>>>>>>>> could cause clang to keep more file handles open?
>>>>>>>>
>>>>>>>> Here's how many files clang had open when I had a breakpoint in
>>>>>>>> that error path:
>>>>>>>>
>>>>>>>> $ lsof -p 91890 | wc -l
>>>>>>>>      343
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>>
>>>>>>>>> Could you find out which of these is going on? Either running in a
>>>>>>>>> debugger or adding some similar printfs to FileSystemStatCache::get()
>>>>>>>>> should be doable.
>>>>>>>>> I'm also going to try to work out how the patch could have
>>>>>>>>> affected this, but new vs correct much easier for me to compare than new vs
>>>>>>>>> old...
>>>>>>>>>
>>>>>>>>
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