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 11:55:56 PST 2019
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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