dexonsmith added inline comments.
================
Comment at: clang/lib/Serialization/ASTReader.cpp:6343
"Invalid data, missing pragma diagnostic states");
- SourceLocation Loc = ReadSourceLocation(F, Record[Idx++]);
- auto IDAndOffset = SourceMgr.getDecomposedLoc(Loc);
- assert(IDAndOffset.first.isValid() && "invalid FileID for transition");
- assert(IDAndOffset.second == 0 && "not a start location for a FileID");
+ FileID FID = ReadFileID(F, Record, Idx);
+ assert(FID.isValid() && "invalid FileID for transition");
----------------
alexfh wrote:
> alexfh wrote:
> > dexonsmith wrote:
> > > alexfh wrote:
> > > > alexfh wrote:
> > > > > jansvoboda11 wrote:
> > > > > > alexfh wrote:
> > > > > > > dexonsmith wrote:
> > > > > > > > eaeltsin wrote:
> > > > > > > > > This doesn't work as before, likely because ReadFileID
> > > > > > > > > doesn't do TranslateSourceLocation.
> > > > > > > > >
> > > > > > > > > Our tests fail.
> > > > > > > > >
> > > > > > > > > I tried calling TranslateSourceLocation here and the tests
> > > > > > > > > passed:
> > > > > > > > > ```
> > > > > > > > > SourceLocation Loc =
> > > > > > > > > Diag.SourceMgr->getComposedLoc(FID, 0);
> > > > > > > > > SourceLocation Loc2 = TranslateSourceLocation(F, Loc);
> > > > > > > > > auto IDAndOffset = SourceMgr.getDecomposedLoc(Loc2);
> > > > > > > > >
> > > > > > > > > // Note that we don't need to set up
> > > > > > > > > Parent/ParentOffset here, because
> > > > > > > > > // we won't be changing the diagnostic state within
> > > > > > > > > imported FileIDs
> > > > > > > > > // (other than perhaps appending to the main source
> > > > > > > > > file, which has no
> > > > > > > > > // parent).
> > > > > > > > > auto &F = Diag.DiagStatesByLoc.Files[IDAndOffset.first];
> > > > > > > > > ```
> > > > > > > > >
> > > > > > > > > Sorry I don't know the codebase, so this fix is definitely
> > > > > > > > > ugly :) But it shows the problem.
> > > > > > > > >
> > > > > > > > I don't think that's the issue, since `ReadFileID()` calls
> > > > > > > > `TranslateFileID`, which should seems like it should be
> > > > > > > > equivalent.
> > > > > > > >
> > > > > > > > However, I notice that the post-increment for `Idx` got
> > > > > > > > dropped! Can you try replacing the line of code with the
> > > > > > > > following and see if that fixes your tests (without any extra
> > > > > > > > TranslateSourceLocation logic)?
> > > > > > > > ```
> > > > > > > > lang=c++
> > > > > > > > FileID FID = ReadFileID(F, Record, Idx++);
> > > > > > > > ```
> > > > > > > >
> > > > > > > > If so, maybe you can contribute that fix with a reduced
> > > > > > > > testcase? I suggest adding me, @vsapsai, @Bigcheese, and
> > > > > > > > @jansvoboda11 as reviewers.
> > > > > > > >
> > > > > > > > @alexfh, maybe you can check if this fixes your tests as well?
> > > > > > > >
> > > > > > > > (If this is the issue, it's a bit surprising we don't have
> > > > > > > > existing tests covering this case... and embarrassing I missed
> > > > > > > > it when reviewing initially!)
> > > > > > > I've noticed the dropped `Idx` post-increment as well, but I went
> > > > > > > a step further and looked at the `ReadFileID` implementation,
> > > > > > > which is actually doing a post-increment itself, and accepts
> > > > > > > `Idx` by reference:
> > > > > > > ```
> > > > > > > FileID ReadFileID(ModuleFile &F, const RecordDataImpl &Record,
> > > > > > > unsigned &Idx) const {
> > > > > > > return TranslateFileID(F, FileID::get(Record[Idx++]));
> > > > > > > }
> > > > > > > ```
> > > > > > >
> > > > > > > Thus, it seems to be correct. But what @eaeltsin has found is
> > > > > > > actually a problem for us. I'm currently trying to make an
> > > > > > > isolated test case, but it's quite tricky (as header modules are
> > > > > > > =\). It may be the case that our build setup relies on something
> > > > > > > clang doesn't explicitly promises, but the fact is that the
> > > > > > > behavior (as observed by our build setup) has changed. I'll try
> > > > > > > to revert the commit for now to get us unblocked and provide a
> > > > > > > test case as soon as I can.
> > > > > > Thanks for helping out @dexonsmith, we did have the week off.
> > > > > >
> > > > > > @eaeltsin @alexfhDone, are you able to provide the failing test
> > > > > > case? I'm happy to look into it and re-land this with a fix.
> > > > > I've spent multiple hours trying to extract an observable test case.
> > > > > It turned out to be too hairy of a yaq to shave: for each compilation
> > > > > a separate sandboxed environment is created with a separate symlink
> > > > > tree with just the inputs necessary for that action. Some of the
> > > > > inputs are prebuilt module files (e.g. for libc++) that are
> > > > > version-locked with the compiler. So far @jgorbe and I could reduce
> > > > > this to four compilation steps with their own symlink trees with
> > > > > inputs. While I could figure out some of the factors that affect
> > > > > reproducibility (for example, symlinks are important, since making a
> > > > > deep copy of the input directories makes the issue disappear), it
> > > > > will take a few more hours of concentrated yak shaving to bring this
> > > > > to a shareable state. I'm not sure I have much more time to sink into
> > > > > investigating this.
> > > > >
> > > > > It seems like examining code based on @eaeltsin's finding may be a
> > > > > more fruitful path to synthesizing a regression test. Could you try
> > > > > following that path?
> > > > One more observation: `-fmodules-embed-all-files` and
> > > > `-Wno-mismatched-tags` compiler options turned out to be important.
> > > Maybe @eaeltsin can help, but I don't see any reason to think that
> > > testcase will be easier. Typically we don't revert without a testcase or
> > > at least some way to understand the problem and make progress.
> > >
> > > (Maybe @jansvoboda11 has ideas for extra instrumentation in the compiler
> > > to better understand what's going on with your setup?)
> > I've managed to get rid of the precompiled module files and now I have
> > something much more observable. It will take some more time to brush it up
> > though.
> The standalone repro is here: {F25463527}
>
> The files should be unpacked to a directory (e.g. /tmp/repro/standalone) and
> the repro.sh script can be invoked with CLANG environment variable pointing
> to the clang binary being tested. The script will create two symlink trees
> and start clang twice. The second clang invocation fails with clang
> containing this patch.
>
> ```
> $ CLANG=/tmp/repro/clang-good /tmp/repro/standalone/repro.sh
> ++ dirname /tmp/repro/standalone/repro.sh
> + DIR=/tmp/repro/standalone
> + cd /tmp/repro/standalone
> + rm -rf 1 2
> + mkdir -p 1/q/a_proto/mypkg 1/p/a_proto/mypkg 2/q/a_proto/mypkg
> 2/p/b_proto/mypkg
> + ln -sf /tmp/repro/standalone/files/a_proto.cppmap 1/
> + ln -sf /tmp/repro/standalone/files/a.pb.h
> /tmp/repro/standalone/files/a.proto.h 1/p/a_proto/mypkg/
> + ln -sf /tmp/repro/standalone/files/a.pb.h
> /tmp/repro/standalone/files/a.proto.h 1/q/a_proto/mypkg/
> + ln -sf /tmp/repro/standalone/files/a_proto.cppmap
> /tmp/repro/standalone/files/b_proto.cppmap 2/
> + ln -sf /tmp/repro/standalone/files/a.pb.h 2/q/a_proto/mypkg/
> + ln -sf /tmp/repro/standalone/files/b.pb.h 2/p/b_proto/mypkg/
> + CC_ARGS=('-Wno-mismatched-tags' '-Xclang=-fmodules-embed-all-files'
> '-Xclang=-fmodules-local-submodule-visibility' '-fmodules'
> '-fno-implicit-modules' '-fno-implicit-module-maps' '-std=gnu++17'
> '-Xclang=-fmodule-map-file-home-is-cwd')
> + export CC_ARGS
> + : /tmp
> + cd /tmp/repro/standalone/1
> + /tmp/repro/clang-good -Wno-mismatched-tags
> -Xclang=-fmodules-embed-all-files
> -Xclang=-fmodules-local-submodule-visibility -fmodules -fno-implicit-modules
> -fno-implicit-module-maps -std=gnu++17 -Xclang=-fmodule-map-file-home-is-cwd
> -I q/a_proto -fmodule-name=//a -fmodule-map-file=a_proto.cppmap -xc++
> -Xclang=-emit-module -c a_proto.cppmap -o /tmp/a.pcm
> + cd /tmp/repro/standalone/2
> + /tmp/repro/clang-good -Wno-mismatched-tags
> -Xclang=-fmodules-embed-all-files
> -Xclang=-fmodules-local-submodule-visibility -fmodules -fno-implicit-modules
> -fno-implicit-module-maps -std=gnu++17 -Xclang=-fmodule-map-file-home-is-cwd
> -I q/b_proto -I q/a_proto -fmodule-name=//b -fmodule-map-file=b_proto.cppmap
> -Xclang=-fmodule-file=/tmp/a.pcm -xc++ -Xclang=-emit-module -c b_proto.cppmap
> -o /tmp/b.pcm
>
> $ CLANG=/tmp/repro/clang-bad /tmp/repro/standalone/repro.sh
> ++ dirname /tmp/repro/standalone/repro.sh
> + DIR=/tmp/repro/standalone
> + cd /tmp/repro/standalone
> + rm -rf 1 2
> + mkdir -p 1/q/a_proto/mypkg 1/p/a_proto/mypkg 2/q/a_proto/mypkg
> 2/p/b_proto/mypkg
> + ln -sf /tmp/repro/standalone/files/a_proto.cppmap 1/
> + ln -sf /tmp/repro/standalone/files/a.pb.h
> /tmp/repro/standalone/files/a.proto.h 1/p/a_proto/mypkg/
> + ln -sf /tmp/repro/standalone/files/a.pb.h
> /tmp/repro/standalone/files/a.proto.h 1/q/a_proto/mypkg/
> + ln -sf /tmp/repro/standalone/files/a_proto.cppmap
> /tmp/repro/standalone/files/b_proto.cppmap 2/
> + ln -sf /tmp/repro/standalone/files/a.pb.h 2/q/a_proto/mypkg/
> + ln -sf /tmp/repro/standalone/files/b.pb.h 2/p/b_proto/mypkg/
> + CC_ARGS=('-Wno-mismatched-tags' '-Xclang=-fmodules-embed-all-files'
> '-Xclang=-fmodules-local-submodule-visibility' '-fmodules'
> '-fno-implicit-modules' '-fno-implicit-module-maps' '-std=gnu++17'
> '-Xclang=-fmodule-map-file-home-is-cwd')
> + export CC_ARGS
> + : /tmp
> + cd /tmp/repro/standalone/1
> + /tmp/repro/clang-bad -Wno-mismatched-tags -Xclang=-fmodules-embed-all-files
> -Xclang=-fmodules-local-submodule-visibility -fmodules -fno-implicit-modules
> -fno-implicit-module-maps -std=gnu++17 -Xclang=-fmodule-map-file-home-is-cwd
> -I q/a_proto -fmodule-name=//a -fmodule-map-file=a_proto.cppmap -xc++
> -Xclang=-emit-module -c a_proto.cppmap -o /tmp/a.pcm
> + cd /tmp/repro/standalone/2
> + /tmp/repro/clang-bad -Wno-mismatched-tags -Xclang=-fmodules-embed-all-files
> -Xclang=-fmodules-local-submodule-visibility -fmodules -fno-implicit-modules
> -fno-implicit-module-maps -std=gnu++17 -Xclang=-fmodule-map-file-home-is-cwd
> -I q/b_proto -I q/a_proto -fmodule-name=//b -fmodule-map-file=b_proto.cppmap
> -Xclang=-fmodule-file=/tmp/a.pcm -xc++ -Xclang=-emit-module -c b_proto.cppmap
> -o /tmp/b.pcm
> While building module '//b':
> In file included from <module-includes>:1:
> In file included from ./p/b_proto/mypkg/b.pb.h:3:
> q/a_proto/mypkg/a.pb.h:3:10: fatal error: 'mypkg/a.proto.h' file not found
> #include "mypkg/a.proto.h"
> ^~~~~~~~~~~~~~~~~
> 1 error generated.
> ```
Great!
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D137213/new/
https://reviews.llvm.org/D137213
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