[CodeView] Emit S_OBJNAME record

[aganea]

Summary

We've had a longstanding incompatibility with MSVC where we don't emit a couple of CodeView records that normally go in each file. This patch aims to address the first of these records - the S_OBJNAME symbol. This symbol is very simple. It just contains the full path to the object file that the debug info is being emitted to.

When building from clang, the approach taken here is to use the target file name, as decided by the CompilerInstance::createDefaultOutputFile. It is then passed down to the backend through MCTargetOptions, to make it available to CodeViewDebug. The same approach is taken when using llc or LTO/ThinLTO (through LLD or llvm-lto2). When emitting to stdout (path is '-'), we emit the S_OBJNAME record with an empty name.

The objective of this patch is to support live code patching tools like Recode or Live++. They are different from Microsoft Edit & Continue, which we don't plan to support. Several changes are needed in LLVM to support these tools:

1. Emit S_OBJNAME (this patch)
2. Emit full cc1 cmd-line in LF_BUILDINFO, see D80833.
3. Emit two-byte nops, see D81301.
4. Emit the 'hotpatch' flag in S_COMPILE3, see D116511.

[rnk]

I'd back out the C API changes, but otherwise this makes sense to me. Let's check with @aprantl, though.

llvm/include/llvm-c/DebugInfo.h

202–203 ↗

(On Diff #133138)

I'd suggest leaving this alone, we can add a LLVMDIBuilderCreateCompileUnit2 if any frontend using the C API ever cares about this.

[aprantl]

Whenever changing IR / IR Metadata there also needs to be a Bitcode upgrade test in test/Bitcode with a .bc file of the old format, and an assembler round-trip test in test/Assembler.

That said, I'm wondering if this isn't a property that is better on the llvm::Module. For example, in an LTO compilation, do you really want the name of the individual bitcode-holding .o files or do you want the name of the lto.o file? Another example is the Swift frontend, which always generates at least DICompileUnits per llvm::Module. It would be more efficient to put, e.g., a NamedMDNode into the module so this information can be shared between the CUs.

[dblaikie]

Does this need to be the name of an actual object file? Any idea how this should work in the case of LTO?

For the .dwo file name, which must be the actual name of the final .dwo file (ie: intermediate IR 'object' file names are not relevant, only the final true object file because that's where the .dwo file comes from) this wasn't passed down through debug info metadata (because at the time the metadata's generated the final object file name is not known - that metadata might be merged, split, Thin merged, etc, before the final object is emitted) but through the MCOptions struct passed into LLVM's MC layer.

[zturner]

In D43002#1000711, @dblaikie wrote:

Does this need to be the name of an actual object file? Any idea how this should work in the case of LTO?

For the .dwo file name, which must be the actual name of the final .dwo file (ie: intermediate IR 'object' file names are not relevant, only the final true object file because that's where the .dwo file comes from) this wasn't passed down through debug info metadata (because at the time the metadata's generated the final object file name is not known - that metadata might be merged, split, Thin merged, etc, before the final object is emitted) but through the MCOptions struct passed into LLVM's MC layer.

I tested with MSVC LTCG (their name for LTO) and here's the behavior it exhibits.

1. When compiling with LTCG and outputting foo.obj, the output file is not recognized as a COFF object file. I believe this matches our behavior of outputting bitcode files.
2. When linking 2 LTCG object files together and getting a final PDB, the object name symbols reference the "pseudo-object files" mentioned in step 1.

I believe the reason for this behavior is that the final PDB contains information about every original compiland, regardless of whether it participated in LTO. I mentioned in the original patch description that the S_OBJNAME symbol is 1 out of 2 symbols that we don't yet emit. The other one emits more info including (among other things) the full command line used to generate the object file. So I think the idea here is that with all of this information combined, given only a PDB a person can reproduce the exact build. For that reason I think this needs to be the original bitcode-holding .o files.

[dblaikie]

Adrian - what do you think about Reid's point regarding not changing the C API unless needed? I'm fairly OK with that, but not sure. Seems like it could be a surprising "gotcha" where someone thinks they're doing the right things to produce CodeView but they're missing this because the API isn't exposed/suggesting that usage.

It would be more efficient to put, e.g., a NamedMDNode into the module so this information can be shared between the CUs.

I assume the string data itself is shared by the bitcode format? But I don't really know.

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

837–842

This is O(N^2) (erase is O(N)) & could be made O(N) (using a technique similar to the erase+remove idiom - using literal erase+remove probably isn't practical due to the stateful nature of the walk).

Is there no other logic for this already elsewhere in LLVM?

855–856

Probably best just to use another/separate declaration here? (I think such a thing might be specified in the style guide, but I'm not sure)

[zturner]

In D43002#1000801, @dblaikie wrote:

It would be more efficient to put, e.g., a NamedMDNode into the module so this information can be shared between the CUs.

I assume the string data itself is shared by the bitcode format? But I don't really know.

All of this code is new to me, so I'm still kind of fumbling along as I learn how all this stuff works together, but my impression was that Adrian's suggestion only really applied if I wanted the name of the lto.o file. Given that I need the name of the bitcode containing .o file, does any of this still apply? Is the current solution appropriate in that case?

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

837–842

Unfortunately there's not. But you're right, I can do this a bit more efficiently by keeping a separate read pointer and write pointer.

[aprantl]

In D43002#1000801, @dblaikie wrote:

Adrian - what do you think about Reid's point regarding not changing the C API unless needed? I'm fairly OK with that, but not sure. Seems like it could be a surprising "gotcha" where someone thinks they're doing the right things to produce CodeView but they're missing this because the API isn't exposed/suggesting that usage.

This depends on whether this is just a nice-to-have feature for Windows or if it is important enough to warrant creating a new API function.

It would be more efficient to put, e.g., a NamedMDNode into the module so this information can be shared between the CUs.

I assume the string data itself is shared by the bitcode format? But I don't really know.

I think that is correct.

There is still the question on how this is supposed to behave in an LTO build? Do you want the name of the shared LTO.o file for all CUs, or do you want to preserve the names of the bitcode-.o files? If the former is the case, then it makes more sense to make this a property of the Module, otherwise it needs to be on the DICompileUnit.

[aprantl]

clang/lib/CodeGen/CGDebugInfo.cpp

567 ↗

(On Diff #133138)

Should this not be gated on the debuginfo kind being codeview?

[zturner]

In D43002#1000838, @aprantl wrote:

This depends on whether this is just a nice-to-have feature for Windows or if it is important enough to warrant creating a new API function.

I can back out the api changes, it doesn't seem important enough to me until there is at least 1 active user of the c api who wants it.

There is still the question on how this is supposed to behave in an LTO build? Do you want the name of the shared LTO.o file for all CUs, or do you want to preserve the names of the bitcode-.o files? If the former is the case, then it makes more sense to make this a property of the Module, otherwise it needs to be on the DICompileUnit.

I mentioned in another response but it might have been overlooked. It needs to be the bitcode-.o files.

clang/lib/CodeGen/CGDebugInfo.cpp

567 ↗

(On Diff #133138)

Couldn't a non-CodeView processor just ignore this field if they aren't interested in it? I can't think of a good reason to gate it at this high of a level.

[aprantl]

In D43002#1000863, @zturner wrote:

In D43002#1000838, @aprantl wrote:

There is still the question on how this is supposed to behave in an LTO build? Do you want the name of the shared LTO.o file for all CUs, or do you want to preserve the names of the bitcode-.o files? If the former is the case, then it makes more sense to make this a property of the Module, otherwise it needs to be on the DICompileUnit.

I mentioned in another response but it might have been overlooked. It needs to be the bitcode-.o files.

Thanks.

Should this not be gated on the debuginfo kind being codeview?

Couldn't a non-CodeView processor just ignore this field if they aren't interested in it? I can't think of a good reason to gate it at this high of a level.

It needlessly increases the size of the intermediate products in the LTO case on non-windows platforms and every time we encode any paths in Clang build products we are inviting problems with non-reproducible builds.
Related question: does remapDIPath do the right thing for the *output* file?

[zturner]

Gated the passing of this flag behind a check for CodeView. I also removed the O(N^2) function anyway in favor of just calling make_absolute. This seems more correct anyway as it will handle the case where the output file is specified as an absolute path already.

[aprantl]

I think this is still missing the bitcode upgrade test.

llvm/test/DebugInfo/COFF/buildinfo.ll

42 ↗

(On Diff #133309)

Please strip all quoted attributes., they are bound to break in future versions

[thakis]

I was about to say "please make sure this honors -fdebug-prefix-map" but I suppose codeview probably contains so many absolute paths at the moment that we should instead have a concerted effort to make debug info cwd-independent at some later point instead.

[zturner]

Adds tests for bitcode upgrade and assembly roundtripping (as well as the necessary fixes to make these tests pass).

[aprantl]

clang/lib/CodeGen/CGDebugInfo.cpp

561 ↗

(On Diff #133446)

You don't need to create a local copy of the string here. You could just use a ?: in the createCompileUnit invocation.

llvm/test/Assembler/cu-outputfile.ll

1 ↗

(On Diff #133446)

We usually do llvm-as < %s | llvm-dis - | llvm-as -| llvm-dis - | FileCheck.

llvm/test/Bitcode/upgrade-cu-outputfile.ll

2 ↗

(On Diff #133446)

There should be a .bc file created by an llvm-as from before this patch checked into the repository and that should be used as input.

[zturner]

Modified the tests as suggested by @aprantl

[zturner]

@aprantl ping

[aprantl]

The only thing that's missing is a test for the correct hashing of the new field in unittests/IR/MetadataTest.cpp.

[aprantl]

To clarify my last comment: No need to check for the correct hashing, since DICompileUnits are always distinct, but extending DICompileUnitTest would be the right thing to do.

[rnk]

I was reviewing the records that msvc emits that clang does not, and I noticed this again.

Here's a thought. Why are we putting this on the compile unit in the first place? Why not use a global named metadata node? Most of the complexity in this patch is from going through DICompileUnit, when we can just claim a global named metadata node for the output object file. It could probably even point to a DIFile so we can preserve some information about whether the path is relative.

[dblaikie]

In D43002#1279796, @rnk wrote:

I was reviewing the records that msvc emits that clang does not, and I noticed this again.

Here's a thought. Why are we putting this on the compile unit in the first place? Why not use a global named metadata node? Most of the complexity in this patch is from going through DICompileUnit, when we can just claim a global named metadata node for the output object file. It could probably even point to a DIFile so we can preserve some information about whether the path is relative.

If this is meant to name the final object file that's emitted - perhaps it shouldn't be in metadata at all. The Split-DWARF DWO file name is similar: it must name the actual file that was emitted - and isn't related to the original modules that may've been generated. This data is passed down through an MCOption, if I recall correctly.

[aganea]

@zturner Do you mind if we took over this patch and finish it? This prevents using Live++ with Clang.

[• mathieupelo]

Hi, I just jumped on this project. I'm currently trying to get S_OBJECTNAME symbol in order to make Live++ work.
I was looking at the feed and I don't understand what you mean @rnk when you say "Why not use a global named metadata node?". Could you please give more clarification on what you mean here, it would help a lot.
Also, @dblaikie if the info shouldn't be in metadata, where do you think it should be ?
Thanks

[rnk]

Thinking about it again, maybe it should be an MCOption like David suggested. S_OBJNAME should probably refer to the final location of the native object file, which is only known to whoever sets up MCOptions. For example, with "fat" LTO, the linker is the one responsible for setting up the output file.

Named metadata nodes are things like !llvm.ident = {...} that you see at global scope in .ll files, but I don't think it's relevant.

As far as this patch is concerned, I don't think we should put this thing on the compile unit. The whole idea of compile units is to preserve the separation between compilation units through LTO, but we can't really do that in codeview anyway.

[• mathieupelo]

Hello, I as requested placed the outputfile name in the MCTargetOptions.h. However, I encountered an issue. @rnk

I didn’t find any way to go back to MCTargetOptions.h from the CompilerInvocation.cpp. I understand it would make sense that there is one somewhere, but I can’t find it. Do any of you know how I’m supposed to access the MCTargetOption? Should I create my own way there?
Sorry to waste your time and maybe the answer is simple to answer but I’m fairly new to this code so there is some aspects of the code I dont fully understand.

[aganea]

I'm taking over this patch, as discussed offline with Zachary.

I've re-implemented the patch to use the target/final file name of the .OBJ, as suggested.

The bulk of the changes is mostly to pass around the file name, down to the back end.

[echristo]

First question:

Since split dwarf has to do some similar things can we not use the same support? This seems to be a lot of changes for this.

Second question:

and if we can't use the same support can we make split dwarf use this? Having two separate methods for passing everything around is a bit painful.

[aganea]

Simplified. Now using CodeGenOptions to pass the object filename around.

[aganea]

In D43002#2061162, @echristo wrote:

First question:

Since split dwarf has to do some similar things can we not use the same support? This seems to be a lot of changes for this.

Second question:

and if we can't use the same support can we make split dwarf use this? Having two separate methods for passing everything around is a bit painful.

To answer both questions, I tried to converge but the uses are slightly different. In one case (DWARF) the -split-dwarf-file/-split-dwarf-output flags are passed down almost blindly to the back-end, whereas for COFF there's more logic to determine where the file should be emitted (see CompilerInstance::createOutputFile). We always need full path names in S_OBJNAME, whereas (it seems) split DWARF can handle relative paths (for example see llvm-mc -split-dwarf-file). I think the purpose is also different: the .dwo is for immediate debugger consumption, whereas the path in S_OBJNAME seems to be used more like a global identifier.

Please let me know if you feel this could be done differently.

[aganea]

Simplify.
Added coverage when using clang-cl since this is a MSVC-specific feature.
When -fdebug-compilation-dir=. is used, relative paths are now emitted in the S_OBJNAME record.

[aganea]

Ping.

[aganea]

Ping!

[rnk]

I think the biggest concern here is what to do about /Fa / -save-temps. If we do nothing, the S_OBJNAME record will change if you run the same compilation twice with and without those flags. Generally, we strive to ensure that the directly emitted object file is identical to one rinsed through textual assembly, but that doesn't always work. I'm not sure if /Fa works reliably since we switched to Intel style assembly syntax either.

clang/include/clang/Basic/CodeGenOptions.h

231

Let's bikeshed the name a bit. This thing is the -o//Fo value, plus some processing. It can be symbolic, as in -. It could be the name of a bitcode file with -flto. It could be the name of an assembly file if you do clang -S --target=x86_64-windows-msvc -g t.cpp -o t.s. It could be the name of an ELF file if you try hard. I think in any of these cases where the user directly emits something that isn't a COFF object, it's OK to use that name for the S_OBJNAME record.

What it is, is the name of the compiler's output file, as we would like it to appear in debug info. With that in mind, here are some ideas:

• CodeViewObjectName: very directly referring to S_OBJNAME
• ObjectFilename: very general
• ObjectFilenameForDebug: generalizing over cv/dwarf
• OutputFilenameForDebug: generalizing over assembly, bc, and obj

I think I like ObjectFilenameForDebug best. DebugObjectFilename seems like a no-go, since that sounds like the dwo file name.

---

This brings me to the case of -save-temps / /Fa. In these cases, the compile action is broken into pieces, and the assembler is invoked in a follow-up process. Does that mean the driver needs to pass an extra flag along to the -cc1 action? That would be a bummer.

clang/lib/Frontend/CompilerInstance.cpp

717 ↗

(On Diff #304364)

I think saving the output file name during output file creation seems like an unexpected side effect for this function. Can we handle it earlier, maybe near dwo file name handling?

clang/test/CodeGenCXX/debug-info-objname.cpp

5

I checked, this is also consistent with clang's regular /Z7 output for source filenames.

21–22

And this is the thing we rely on, so it should all work.

llvm/include/llvm/MC/MCTargetOptions.h

65

This should probably be in llvm/include/llvm/Target/TargetOptions.h. I think MCTargetOptions is intended to control assembler behavior, but this option is read while producing assembly in CodeGen, not during assembling.

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

788

This isn't unescaping them, it's just canonicalizing double slashes to one slash, right? Would llvm::sys::native suffice?

[aganea]

clang/include/clang/Basic/CodeGenOptions.h

231

I think we should fix -save-temps and /Fa, thanks for raising that! Would you mind if I added a new cc1 flag for that purpose? Something like -target-file-name.
When using -save-temps, each cc1 command doesn't know about the final filename, except for the last cc1 command. We would need to provide that name somehow when passing -S.

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

788

llvm::sys::path::native() doesn't remove consecutive (back)slashes. I think @zturner's main intent was when debugging in Visual Studio with arguments from LIT tests, they sometimes contain double backslashes.

[rnk]

clang/include/clang/Basic/CodeGenOptions.h

231

Yes, I think we'll need a new cc1 flag. I'd avoid "target" in the flag name, since it makes me thing of target as in platform, OS, ISA, etc. Maybe just -object-file-name? It's very boring, and reasonably specific.

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

788

I see. I think "unescape" shouldn't be in the name, this isn't about escape characters, it's about cleaning up or canonicalizing the path.

[dpaoliello]

@rnk @aganea Ping... Just wanted to see what was happening with this change, and if there is anything I can do to help get it merged in.

[aganea]

As suggested by @rnk

[aganea]

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

788

I removed this function. Now using sys::path::remove_dots which removes the consecutive slashes.

[aganea]

Ping! Any further comments? Thanks in advance for your time.

[rnk]

lgtm

Sorry for the delay, I got sick last week and read through email newest to oldest.

[MaskRay]

Some test nits:) I don't know CodeView :(

clang/test/CodeGenCXX/debug-info-objname.cpp

1

The whole file appears to be CRLF where almost all other tests use LF in llvm-project.

2

%T is deprecated in lit (https://llvm.org/docs/CommandGuide/lit.html#substitutions): it is easy to cause multi-threading file reuse problems because lit runs tests parallelly.

I personally prefer RUN: rm -rf %t && mkdir %t && cd %t if you need to cd.

My personal comment style for non-RUN non-CHECK lines is /// - it stands out in many editors and may help possible FileCheck/lit's future direction to catch stale CHECK prefixes.

30

Prefer --input-file or input redirection to cat xxx | yyy

36

{{[0-9]+}} -> [[#]]

[aganea]

In D43002#3205190, @MaskRay wrote:

Some test nits:) I don't know CodeView :(

Fixed, thanks @MaskRay !

clang/include/clang/Basic/CodeGenOptions.h

public:
 
   /// The name for the split debug info file used for the DW_AT_[GNU_]dwo_name
   /// attribute in the skeleton CU.
   std::string SplitDwarfFile;
 
   /// Output filename for the split debug info, not used in the skeleton CU.
   std::string SplitDwarfOutput;
 
+  /// Output filename used in the COFF debug information.
+  std::string ObjectFilenameForDebug;
+
   /// The name of the relocation model to use.
   llvm::Reloc::Model RelocationModel;
 
   /// If not an empty string, trap intrinsics are lowered to calls to this
   /// function instead of to trap instructions.
   std::string TrapFuncName;
 
   /// A list of dependent libraries.

clang/include/clang/Driver/Job.h

public:
   }
 
   /// Sets the environment to be used by the new process.
   /// \param NewEnvironment An array of environment variables.
   /// \remark If the environment remains unset, then the environment
   ///         from the parent process will be used.
   virtual void setEnvironment(llvm::ArrayRef<const char *> NewEnvironment);
 
+  void replaceArguments(llvm::opt::ArgStringList List) {
+    Arguments = std::move(List);
+  }
+
   const char *getExecutable() const { return Executable; }
 
   const llvm::opt::ArgStringList &getArguments() const { return Arguments; }
 
   const std::vector<InputInfo> &getInputInfos() const { return InputInfoList; }
 
   const std::vector<std::string> &getOutputFilenames() const {
     return OutputFilenames;

clang/include/clang/Driver/Options.td

def nostdincxx : Flag<["-"], "nostdinc++">, Flags<[CC1Option]>,
   MarshallingInfoNegativeFlag<HeaderSearchOpts<"UseStandardCXXIncludes">>;
 def nostdlib : Flag<["-"], "nostdlib">, Group<Link_Group>;
 def nostdlibxx : Flag<["-"], "nostdlib++">;
 def object : Flag<["-"], "object">;
 def o : JoinedOrSeparate<["-"], "o">, Flags<[NoXarchOption, RenderAsInput,
   CC1Option, CC1AsOption, FC1Option, FlangOption]>,
   HelpText<"Write output to <file>">, MetaVarName<"<file>">,
   MarshallingInfoString<FrontendOpts<"OutputFile">>;
+def object_file_name_EQ : Joined<["-"], "object-file-name=">, Flags<[CC1Option, CC1AsOption, CoreOption]>,
+  HelpText<"Set the output <file> for debug infos">, MetaVarName<"<file>">,
+  MarshallingInfoString<CodeGenOpts<"ObjectFilenameForDebug">>;
+def object_file_name : Separate<["-"], "object-file-name">, Flags<[CC1Option, CC1AsOption, CoreOption]>,
+    Alias<object_file_name_EQ>;
 def pagezero__size : JoinedOrSeparate<["-"], "pagezero_size">;
 def pass_exit_codes : Flag<["-", "--"], "pass-exit-codes">, Flags<[Unsupported]>;
 def pedantic_errors : Flag<["-", "--"], "pedantic-errors">, Group<pedantic_Group>, Flags<[CC1Option]>,
   MarshallingInfoFlag<DiagnosticOpts<"PedanticErrors">>;
 def pedantic : Flag<["-", "--"], "pedantic">, Group<pedantic_Group>, Flags<[CC1Option,FlangOption,FC1Option]>,
   HelpText<"Warn on language extensions">, MarshallingInfoFlag<DiagnosticOpts<"Pedantic">>;
 def pg : Flag<["-"], "pg">, HelpText<"Enable mcount instrumentation">, Flags<[CC1Option]>,
   MarshallingInfoFlag<CodeGenOpts<"InstrumentForProfiling">>;

clang/lib/CodeGen/BackendUtil.cpp

if (!Entry.IsFramework &&
         (Entry.Group == frontend::IncludeDirGroup::Quoted ||
          Entry.Group == frontend::IncludeDirGroup::Angled ||
          Entry.Group == frontend::IncludeDirGroup::System))
       Options.MCOptions.IASSearchPaths.push_back(
           Entry.IgnoreSysRoot ? Entry.Path : HSOpts.Sysroot + Entry.Path);
   Options.MCOptions.Argv0 = CodeGenOpts.Argv0;
   Options.MCOptions.CommandLineArgs = CodeGenOpts.CommandLineArgs;
   Options.DebugStrictDwarf = CodeGenOpts.DebugStrictDwarf;
+  Options.ObjectFilenameForDebug = CodeGenOpts.ObjectFilenameForDebug;
 
   return true;
 }
 
 static Optional<GCOVOptions> getGCOVOptions(const CodeGenOptions &CodeGenOpts,
                                             const LangOptions &LangOpts) {
   if (!CodeGenOpts.EmitGcovArcs && !CodeGenOpts.EmitGcovNotes)
     return None;
static void runThinLTOBackend(
   // We can simply import the values mentioned in the combined index, since
   // we should only invoke this using the individual indexes written out
   // via a WriteIndexesThinBackend.
   FunctionImporter::ImportMapTy ImportList;
   if (!lto::initImportList(*M, *CombinedIndex, ImportList))
     return;
 
   auto AddStream = [&](size_t Task) {
-    return std::make_unique<CachedFileStream>(std::move(OS));
+    return std::make_unique<CachedFileStream>(std::move(OS),
+                                              CGOpts.ObjectFilenameForDebug);
   };
   lto::Config Conf;
   if (CGOpts.SaveTempsFilePrefix != "") {
     if (Error E = Conf.addSaveTemps(CGOpts.SaveTempsFilePrefix + ".",
                                     /* UseInputModulePath */ false)) {
       handleAllErrors(std::move(E), [&](ErrorInfoBase &EIB) {
         errs() << "Error setting up ThinLTO save-temps: " << EIB.message()
                << '\n';

clang/lib/Driver/ToolChains/Clang.cpp

if (NoOmitFP || mustUseNonLeafFramePointerForTarget(Triple) ||
     if (OmitLeafFP)
       return CodeGenOptions::FramePointerKind::NonLeaf;
     return CodeGenOptions::FramePointerKind::All;
   }
   return CodeGenOptions::FramePointerKind::None;
 }
 
 /// Add a CC1 option to specify the debug compilation directory.
-static void addDebugCompDirArg(const ArgList &Args, ArgStringList &CmdArgs,
+static const char *addDebugCompDirArg(const ArgList &Args,
+                                      ArgStringList &CmdArgs,
                                       const llvm::vfs::FileSystem &VFS) {
   if (Arg *A = Args.getLastArg(options::OPT_ffile_compilation_dir_EQ,
                                options::OPT_fdebug_compilation_dir_EQ)) {
     if (A->getOption().matches(options::OPT_ffile_compilation_dir_EQ))
       CmdArgs.push_back(Args.MakeArgString(Twine("-fdebug-compilation-dir=") +
                                            A->getValue()));
     else
       A->render(Args, CmdArgs);
   } else if (llvm::ErrorOr<std::string> CWD =
                  VFS.getCurrentWorkingDirectory()) {
     CmdArgs.push_back(Args.MakeArgString("-fdebug-compilation-dir=" + *CWD));
   }
+  StringRef Path(CmdArgs.back());
+  return Path.substr(Path.find('=') + 1).data();
+}
+
+static void addDebugObjectName(const ArgList &Args, ArgStringList &CmdArgs,
+                               const char *DebugCompilationDir,
+                               const char *OutputFileName) {
+  // No need to generate a value for -object-file-name if it was provided.
+  for (auto *Arg : Args.filtered(options::OPT_Xclang))
+    if (StringRef(Arg->getValue()).startswith("-object-file-name"))
+      return;
+
+  if (Args.hasArg(options::OPT_object_file_name_EQ))
+    return;
+
+  SmallString<128> ObjFileNameForDebug(OutputFileName);
+  if (ObjFileNameForDebug != "-" &&
+      !llvm::sys::path::is_absolute(ObjFileNameForDebug) &&
+      (!DebugCompilationDir ||
+       llvm::sys::path::is_absolute(DebugCompilationDir))) {
+    // Make the path absolute in the debug infos like MSVC does.
+    llvm::sys::fs::make_absolute(ObjFileNameForDebug);
+  }
+  CmdArgs.push_back(
+      Args.MakeArgString(Twine("-object-file-name=") + ObjFileNameForDebug));
 }
 
 /// Add a CC1 and CC1AS option to specify the debug file path prefix map.
 static void addDebugPrefixMapArg(const Driver &D, const ArgList &Args, ArgStringList &CmdArgs) {
   for (const Arg *A : Args.filtered(options::OPT_ffile_prefix_map_EQ,
                                     options::OPT_fdebug_prefix_map_EQ)) {
     StringRef Map = A->getValue();
     if (!Map.contains('='))
if (Arg *Asm = Args.getLastArg(options::OPT_fasm, options::OPT_fno_asm)) {
     else
       CmdArgs.push_back("-fno-gnu-keywords");
   }
 
   if (!ShouldEnableAutolink(Args, TC, JA))
     CmdArgs.push_back("-fno-autolink");
 
   // Add in -fdebug-compilation-dir if necessary.
+  const char *DebugCompilationDir =
       addDebugCompDirArg(Args, CmdArgs, D.getVFS());
 
   addDebugPrefixMapArg(D, Args, CmdArgs);
 
   if (Arg *A = Args.getLastArg(options::OPT_ftemplate_depth_,
                                options::OPT_ftemplate_depth_EQ)) {
     CmdArgs.push_back("-ftemplate-depth");
     CmdArgs.push_back(A->getValue());
   }

   if (Arg *A = Args.getLastArg(options::OPT_fsymbol_partition_EQ)) {
     std::string Str = A->getAsString(Args);
     if (!TC.getTriple().isOSBinFormatELF())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << Str << TC.getTripleString();
     CmdArgs.push_back(Args.MakeArgString(Str));
   }
 
+  // Add the output path to the object file for CodeView debug infos.
+  if (EmitCodeView && Output.isFilename())
+    addDebugObjectName(Args, CmdArgs, DebugCompilationDir,
+                       Output.getFilename());
+
   // Add the "-o out -x type src.c" flags last. This is done primarily to make
   // the -cc1 command easier to edit when reproducing compiler crashes.
   if (Output.getType() == types::TY_Dependencies) {
     // Handled with other dependency code.
   } else if (Output.isFilename()) {
     if (Output.getType() == clang::driver::types::TY_IFS_CPP ||
         Output.getType() == clang::driver::types::TY_IFS) {
       SmallString<128> OutputFilename(Output.getFilename());
void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
 
   // Ignore explicit -force_cpusubtype_ALL option.
   (void)Args.hasArg(options::OPT_force__cpusubtype__ALL);
 
   // Pass along any -I options so we get proper .include search paths.
   Args.AddAllArgs(CmdArgs, options::OPT_I_Group);
 
   // Determine the original source input.
-  const Action *SourceAction = &JA;
-  while (SourceAction->getKind() != Action::InputClass) {
-    assert(!SourceAction->getInputs().empty() && "unexpected root action!");
-    SourceAction = SourceAction->getInputs()[0];
+  auto FindSource = [](const Action *S) -> const Action * {
+    while (S->getKind() != Action::InputClass) {
+      assert(!S->getInputs().empty() && "unexpected root action!");
+      S = S->getInputs()[0];
     }
+    return S;
+  };
+  const Action *SourceAction = FindSource(&JA);
 
   // Forward -g and handle debug info related flags, assuming we are dealing
   // with an actual assembly file.
   bool WantDebug = false;
   Args.ClaimAllArgs(options::OPT_g_Group);
   if (Arg *A = Args.getLastArg(options::OPT_g_Group))
     WantDebug = !A->getOption().matches(options::OPT_g0) &&
                 !A->getOption().matches(options::OPT_ggdb0);
 
   unsigned DwarfVersion = ParseDebugDefaultVersion(getToolChain(), Args);
   if (const Arg *GDwarfN = getDwarfNArg(Args))
     DwarfVersion = DwarfVersionNum(GDwarfN->getSpelling());
 
   if (DwarfVersion == 0)
     DwarfVersion = getToolChain().GetDefaultDwarfVersion();
 
   codegenoptions::DebugInfoKind DebugInfoKind = codegenoptions::NoDebugInfo;
 
+  // Add the -fdebug-compilation-dir flag if needed.
+  const char *DebugCompilationDir =
+      addDebugCompDirArg(Args, CmdArgs, C.getDriver().getVFS());
+
   if (SourceAction->getType() == types::TY_Asm ||
       SourceAction->getType() == types::TY_PP_Asm) {
     // You might think that it would be ok to set DebugInfoKind outside of
     // the guard for source type, however there is a test which asserts
     // that some assembler invocation receives no -debug-info-kind,
     // and it's not clear whether that test is just overly restrictive.
     DebugInfoKind = (WantDebug ? codegenoptions::DebugInfoConstructor
                                : codegenoptions::NoDebugInfo);
-    // Add the -fdebug-compilation-dir flag if needed.
-    addDebugCompDirArg(Args, CmdArgs, C.getDriver().getVFS());
 
     addDebugPrefixMapArg(getToolChain().getDriver(), Args, CmdArgs);
 
     // Set the AT_producer to the clang version when using the integrated
     // assembler on assembly source files.
     CmdArgs.push_back("-dwarf-debug-producer");
     CmdArgs.push_back(Args.MakeArgString(getClangFullVersion()));
 
void ClangAs::ConstructJob(Compilation &C, const JobAction &JA,
   // FIXME: Stop lying and consume only the appropriate driver flags
   Args.ClaimAllArgs(options::OPT_W_Group);
 
   CollectArgsForIntegratedAssembler(C, Args, CmdArgs,
                                     getToolChain().getDriver());
 
   Args.AddAllArgs(CmdArgs, options::OPT_mllvm);
 
+  if (DebugInfoKind > codegenoptions::NoDebugInfo && Output.isFilename())
+    addDebugObjectName(Args, CmdArgs, DebugCompilationDir,
+                       Output.getFilename());
+
+  // Fixup any previous commands that use -object-file-name because when we
+  // generated them, the final .obj name wasn't yet known.
+  for (Command &J : C.getJobs()) {
+    if (SourceAction != FindSource(&J.getSource()))
+      continue;
+    auto &JArgs = J.getArguments();
+    for (unsigned I = 0; I < JArgs.size(); ++I) {
+      if (StringRef(JArgs[I]).startswith("-object-file-name=") &&
+          Output.isFilename()) {
+        ArgStringList NewArgs(JArgs.begin(), JArgs.begin() + I);
+        addDebugObjectName(Args, NewArgs, DebugCompilationDir,
+                           Output.getFilename());
+        NewArgs.append(JArgs.begin() + I + 1, JArgs.end());
+        J.replaceArguments(NewArgs);
+        break;
+      }
+    }
+  }
+
   assert(Output.isFilename() && "Unexpected lipo output.");
   CmdArgs.push_back("-o");
   CmdArgs.push_back(Output.getFilename());
 
   const llvm::Triple &T = getToolChain().getTriple();
   Arg *A;
   if (getDebugFissionKind(D, Args, A) == DwarfFissionKind::Split &&
       T.isOSBinFormatELF()) {

clang/test/CMakeLists.txt

list(APPEND CLANG_TEST_DEPS
     llvm-dis
     llvm-dwarfdump
     llvm-ifs
     llvm-lto2
     llvm-modextract
     llvm-nm
     llvm-objcopy
     llvm-objdump
+    llvm-pdbutil
     llvm-profdata
     llvm-rc
     llvm-readelf
     llvm-readobj
     llvm-strip
     llvm-symbolizer
     llvm-windres
     opt

clang/test/CodeGenCXX/debug-info-objname.cpp

+// RUN: cp %s %T/debug-info-objname.cpp
+// RUN: cd %T
+
+// No output file provided, input file is relative, we emit an absolute path (MSVC behavior).
+// RUN: %clang_cl /c /Z7 -nostdinc debug-info-objname.cpp
+// RUN: llvm-pdbutil dump -all debug-info-objname.obj | FileCheck %s --check-prefix=ABSOLUTE
+
+// No output file provided, input file is absolute, we emit an absolute path (MSVC behavior).
+// RUN: %clang_cl /c /Z7 -nostdinc -- %T/debug-info-objname.cpp
+// RUN: llvm-pdbutil dump -all debug-info-objname.obj | FileCheck %s --check-prefix=ABSOLUTE
+
+// The output file is provided as an absolute path, we emit an absolute path.
+// RUN: %clang_cl /c /Z7 -nostdinc /Fo%T/debug-info-objname.obj -- %T/debug-info-objname.cpp
+// RUN: llvm-pdbutil dump -all debug-info-objname.obj | FileCheck %s --check-prefix=ABSOLUTE
+
+// The output file is provided as relative path, -working-dir is provided, we emit an absolute path.
+// RUN: %clang_cl /c /Z7 -nostdinc -working-dir=%T debug-info-objname.cpp
+// RUN: llvm-pdbutil dump -all debug-info-objname.obj | FileCheck %s --check-prefix=ABSOLUTE
+
+// The input file name is relative and we specify -fdebug-compilation-dir, we emit a relative path.
+// RUN: %clang_cl /c /Z7 -nostdinc -fdebug-compilation-dir=. debug-info-objname.cpp
+// RUN: llvm-pdbutil dump -all debug-info-objname.obj | FileCheck %s --check-prefix=RELATIVE
+
+// Ensure /FA emits an .asm file which contains the path to the final .obj, not the .asm
+// RUN: %clang_cl /c /Z7 -nostdinc -fdebug-compilation-dir=. /FA debug-info-objname.cpp
+// RUN: cat debug-info-objname.asm | FileCheck %s --check-prefix=ASM
+
+// Same thing for -save-temps
+// RUN: %clang_cl /c /Z7 -nostdinc -fdebug-compilation-dir=. /clang:-save-temps debug-info-objname.cpp
+// RUN: cat debug-info-objname.asm | FileCheck %s --check-prefix=ASM
+
+int main() {
+  return 1;
+}
+
+// ABSOLUTE: S_OBJNAME [size = {{[0-9]+}}] sig=0, `{{.+}}debug-info-objname.obj`
+// RELATIVE: S_OBJNAME [size = {{[0-9]+}}] sig=0, `debug-info-objname.obj`
+// ASM: Record kind: S_OBJNAME
+// ASM-NEXT: .long   0
+// ASM-NEXT: .asciz  "debug-info-objname.obj"

llvm/include/llvm/MC/MCTargetOptions.h

public:
   bool PreserveAsmComments : 1;
 
   bool Dwarf64 : 1;
   int DwarfVersion = 0;
 
   std::string ABIName;
   std::string AssemblyLanguage;
   std::string SplitDwarfFile;
+  std::string COFFOutputFilename;
 
   const char *Argv0 = nullptr;
   ArrayRef<const char *> CommandLineArgs;
 
   /// Additional paths to search for `.include` directives when using the
   /// integrated assembler.
   std::vector<std::string> IASSearchPaths;
 

llvm/include/llvm/Support/Caching.h

 class MemoryBuffer;
 
 /// This class wraps an output stream for a file. Most clients should just be
 /// able to return an instance of this base class from the stream callback, but
 /// if a client needs to perform some action after the stream is written to,
 /// that can be done by deriving from this class and overriding the destructor.
 class CachedFileStream {
 public:
-  CachedFileStream(std::unique_ptr<raw_pwrite_stream> OS) : OS(std::move(OS)) {}
+  CachedFileStream(std::unique_ptr<raw_pwrite_stream> OS,
+                   std::string OSPath = "")
+      : OS(std::move(OS)), ObjectPathName(OSPath) {}
   std::unique_ptr<raw_pwrite_stream> OS;
+  std::string ObjectPathName;
   virtual ~CachedFileStream() = default;
 };
 
 /// This type defines the callback to add a file that is generated on the fly.
 ///
 /// Stream callbacks must be thread safe.
 using AddStreamFn =
     std::function<Expected<std::unique_ptr<CachedFileStream>>(unsigned Task)>;

llvm/include/llvm/Support/ToolOutputFile.h

 ///   - The file is automatically deleted when the ToolOutputFile
 ///     object is destroyed unless the client calls keep().
 class ToolOutputFile {
   /// This class is declared before the raw_fd_ostream so that it is constructed
   /// before the raw_fd_ostream is constructed and destructed after the
   /// raw_fd_ostream is destructed. It installs cleanups in its constructor and
   /// uninstalls them in its destructor.
   class CleanupInstaller {
+  public:
     /// The name of the file.
     std::string Filename;
-  public:
+
     /// The flag which indicates whether we should not delete the file.
     bool Keep;
 
     StringRef getFilename() { return Filename; }
     explicit CleanupInstaller(StringRef Filename);
     ~CleanupInstaller();
   } Installer;
 
public:
   raw_fd_ostream &os() { return *OS; }
 
   /// Return the filename initialized with.
   StringRef getFilename() { return Installer.getFilename(); }
 
   /// Indicate that the tool's job wrt this output file has been successful and
   /// the file should not be deleted.
   void keep() { Installer.Keep = true; }
+
+  const std::string &outputFilename() { return Installer.Filename; }
 };
 
 } // end llvm namespace
 
 #endif

llvm/include/llvm/Target/TargetOptions.h

public:
 
     DenormalMode getDenormalMode(const fltSemantics &FPType) const;
 
     /// What exception model to use
     ExceptionHandling ExceptionModel = ExceptionHandling::None;
 
     /// Machine level options.
     MCTargetOptions MCOptions;
+
+    /// Stores the filename/path of the final .o/.obj file, to be written in the
+    /// debug information. This is used for emitting the CodeView S_OBJNAME
+    /// record.
+    std::string ObjectFilenameForDebug;
   };
 
 } // End llvm namespace
 
 #endif

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.h

class LLVM_LIBRARY_VISIBILITY CodeViewDebug : public DebugHandlerBase {
   /// section. Appears at the front of every .debug$S or .debug$T or .debug$P
   /// section.
   void emitCodeViewMagicVersion();
 
   void emitTypeInformation();
 
   void emitTypeGlobalHashes();
 
+  void emitObjName();
+
   void emitCompilerInformation();
 
   void emitBuildInfo();
 
   void emitInlineeLinesSubsection();
 
   void emitDebugInfoForThunk(const Function *GV,
                              FunctionInfo &FI,

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

void CodeViewDebug::endModule() {
   // of the payload followed by the payload itself.  The subsections are 4-byte
   // aligned.
 
   // Use the generic .debug$S section, and make a subsection for all the inlined
   // subprograms.
   switchToDebugSectionForSymbol(nullptr);
 
   MCSymbol *CompilerInfo = beginCVSubsection(DebugSubsectionKind::Symbols);
+  emitObjName();
   emitCompilerInformation();
   endCVSubsection(CompilerInfo);
 
   emitInlineeLinesSubsection();
 
   // Emit per-function debug information.
   for (auto &P : FnDebugInfo)
     if (!P.first->isDeclarationForLinker())
for (const auto &GHR : TypeTable.hashes()) {
     }
     assert(GHR.Hash.size() == 8);
     StringRef S(reinterpret_cast<const char *>(GHR.Hash.data()),
                 GHR.Hash.size());
     OS.emitBinaryData(S);
   }
 }
 
+void CodeViewDebug::emitObjName() {
+  MCSymbol *CompilerEnd = beginSymbolRecord(SymbolKind::S_OBJNAME);
+
+  StringRef PathRef(Asm->TM.Options.ObjectFilenameForDebug);
+  llvm::SmallString<256> PathStore(PathRef);
+
+  if (PathRef.empty() || PathRef == "-") {
+    // Don't emit the filename if we're writing to stdout or to /dev/null.
+    PathRef = {};
+  } else {
+    llvm::sys::path::remove_dots(PathStore, /*remove_dot_dot=*/true);
+    PathRef = PathStore;
+  }
+
+  OS.AddComment("Signature");
+  OS.emitIntValue(0, 4);
+
+  OS.AddComment("Object name");
+  emitNullTerminatedSymbolName(OS, PathRef);
+
+  endSymbolRecord(CompilerEnd);
+}
+
 namespace {
 struct Version {
   int Part[4];
 };
 } // end anonymous namespace
 
 // Takes a StringRef like "clang 4.0.0.0 (other nonsense 123)" and parses out
 // the version number.
if (isdigit(C)) {
         return V;
     } else if (N > 0)
       return V;
   }
   return V;
 }
 
 void CodeViewDebug::emitCompilerInformation() {
   MCSymbol *CompilerEnd = beginSymbolRecord(SymbolKind::S_COMPILE3);
   uint32_t Flags = 0;
 
   // The low byte of the flags indicates the source language.
   Flags = CurrentSourceLanguage;
   // TODO:  Figure out which other flags need to be set.
   if (MMI->getModule()->getProfileSummary(/*IsCS*/ false) != nullptr) {
     Flags |= static_cast<uint32_t>(CompileSym3Flags::PGO);
   }
 
   OS.AddComment("Flags and language");
   OS.emitInt32(Flags);
 
   OS.AddComment("CPUType");
   OS.emitInt16(static_cast<uint64_t>(TheCPU));
 
   NamedMDNode *CUs = MMI->getModule()->getNamedMetadata("llvm.dbg.cu");
   const MDNode *Node = *CUs->operands().begin();
   const auto *CU = cast<DICompileUnit>(Node);
 
   StringRef CompilerVersion = CU->getProducer();
   Version FrontVer = parseVersion(CompilerVersion);
   OS.AddComment("Frontend version");
   for (int N : FrontVer.Part)
     OS.emitInt16(N);
 
   // Some Microsoft tools, like Binscope, expect a backend version number of at
   // least 8.something, so we'll coerce the LLVM version into a form that

llvm/lib/LTO/LTOBackend.cpp

if (EC)
       report_fatal_error(Twine("Failed to open ") + DwoFile + ": " +
                          EC.message());
   }
 
   Expected<std::unique_ptr<CachedFileStream>> StreamOrErr = AddStream(Task);
   if (Error Err = StreamOrErr.takeError())
     report_fatal_error(std::move(Err));
   std::unique_ptr<CachedFileStream> &Stream = *StreamOrErr;
+  TM->Options.ObjectFilenameForDebug = Stream->ObjectPathName;
+
   legacy::PassManager CodeGenPasses;
   CodeGenPasses.add(
       createImmutableModuleSummaryIndexWrapperPass(&CombinedIndex));
   if (Conf.PreCodeGenPassesHook)
     Conf.PreCodeGenPassesHook(CodeGenPasses);
   if (TM->addPassesToEmitFile(CodeGenPasses, *Stream->OS,
                               DwoOut ? &DwoOut->os() : nullptr,
                               Conf.CGFileType))

llvm/lib/Support/Caching.cpp

if (EC != errc::no_such_file_or_directory && EC != errc::permission_denied)
       return createStringError(EC, Twine("Failed to open cache file ") +
                                        EntryPath + ": " + EC.message() + "\n");
 
     // This file stream is responsible for commiting the resulting file to the
     // cache and calling AddBuffer to add it to the link.
     struct CacheStream : CachedFileStream {
       AddBufferFn AddBuffer;
       sys::fs::TempFile TempFile;
-      std::string EntryPath;
       unsigned Task;
 
       CacheStream(std::unique_ptr<raw_pwrite_stream> OS, AddBufferFn AddBuffer,
                   sys::fs::TempFile TempFile, std::string EntryPath,
                   unsigned Task)
-          : CachedFileStream(std::move(OS)), AddBuffer(std::move(AddBuffer)),
-            TempFile(std::move(TempFile)), EntryPath(std::move(EntryPath)),
+          : CachedFileStream(std::move(OS), std::move(EntryPath)),
+            AddBuffer(std::move(AddBuffer)), TempFile(std::move(TempFile)),
             Task(Task) {}
 
       ~CacheStream() {
         // TODO: Manually commit rather than using non-trivial destructor,
         // allowing to replace report_fatal_errors with a return Error.
 
         // Make sure the stream is closed before committing it.
         OS.reset();
 
         // Open the file first to avoid racing with a cache pruner.
         ErrorOr<std::unique_ptr<MemoryBuffer>> MBOrErr =
             MemoryBuffer::getOpenFile(
-                sys::fs::convertFDToNativeFile(TempFile.FD), EntryPath,
+                sys::fs::convertFDToNativeFile(TempFile.FD), ObjectPathName,
                 /*FileSize=*/-1, /*RequiresNullTerminator=*/false);
         if (!MBOrErr)
           report_fatal_error(Twine("Failed to open new cache file ") +
                              TempFile.TmpName + ": " +
                              MBOrErr.getError().message() + "\n");
 
         // On POSIX systems, this will atomically replace the destination if
         // it already exists. We try to emulate this on Windows, but this may
         // fail with a permission denied error (for example, if the destination
         // is currently opened by another process that does not give us the
         // sharing permissions we need). Since the existing file should be
         // semantically equivalent to the one we are trying to write, we give
         // AddBuffer a copy of the bytes we wrote in that case. We do this
         // instead of just using the existing file, because the pruner might
         // delete the file before we get a chance to use it.
-        Error E = TempFile.keep(EntryPath);
+        Error E = TempFile.keep(ObjectPathName);
         E = handleErrors(std::move(E), [&](const ECError &E) -> Error {
           std::error_code EC = E.convertToErrorCode();
           if (EC != errc::permission_denied)
             return errorCodeToError(EC);
 
           auto MBCopy = MemoryBuffer::getMemBufferCopy((*MBOrErr)->getBuffer(),
-                                                       EntryPath);
+                                                       ObjectPathName);
           MBOrErr = std::move(MBCopy);
 
           // FIXME: should we consume the discard error?
           consumeError(TempFile.discard());
 
           return Error::success();
         });
 
         if (E)
           report_fatal_error(Twine("Failed to rename temporary file ") +
-                             TempFile.TmpName + " to " + EntryPath + ": " +
+                             TempFile.TmpName + " to " + ObjectPathName + ": " +
                              toString(std::move(E)) + "\n");
 
         AddBuffer(Task, std::move(*MBOrErr));
       }
     };
 
     return [=](size_t Task) -> Expected<std::unique_ptr<CachedFileStream>> {
       // Write to a temporary to avoid race condition

llvm/test/DebugInfo/COFF/globals.ll

 ; RUN: llc < %s | FileCheck %s --check-prefix=ASM
 ; RUN: llc < %s -filetype=obj | llvm-readobj - --codeview | FileCheck %s --check-prefix=OBJ
 ; RUN: llc < %s | llvm-mc -filetype=obj --triple=x86_64-windows | llvm-readobj - --codeview | FileCheck %s --check-prefix=OBJ
-; RUN: llc < %s -filetype=obj | obj2yaml | FileCheck %s --check-prefix=YAML
+; RUN: llc < %s -filetype=obj | obj2yaml | FileCheck %s --check-prefixes=YAML,YAML-STDOUT
+; RUN: llc < %s -filetype=obj -o %t
+; RUN: obj2yaml < %t | FileCheck %s --check-prefixes=YAML,YAML-FILE
 
 ; C++ source to regenerate:
 ; $ cat a.cpp
 ; int first;
 ; 
 ; template <typename T> struct A { static const int comdat = 3; };
 ; 
 ; thread_local const int *middle = &A<void>::comdat;

 ; OBJ-NEXT:      DisplayName: foo::Data::DataStatic
 ; OBJ-NEXT:      LinkageName: ?DataStatic@Data@foo@@2HA
 ; OBJ-NEXT:    }
 
 ; YAML-LABEL:  - Name:            '.debug$S'
 ; YAML:    Subsections:
 ; YAML:      - !Symbols
 ; YAML:        Records:
+; YAML:          - Kind:            S_OBJNAME
+; YAML:            ObjNameSym:
+; YAML:               Signature:       0
+; YAML-STDOUT:        ObjectName:      ''
+; YAML-FILE:          ObjectName:      '{{.*}}'
 ; YAML:          - Kind:            S_COMPILE3
 ; YAML:            Compile3Sym:
 
 ; YAML:      - !Symbols
 ; YAML-NEXT:        Records:
 ; YAML-LABEL:        - Kind:            S_GDATA32
 ; YAML-NEXT:            DataSym:
 ; YAML-NOT: Segment

llvm/test/DebugInfo/COFF/multifunction.ll

 ; String table
 ; X64: .cv_stringtable
 
 ; OBJ64:    Section {
 ; OBJ64:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ64:      Characteristics [ (0x42300040)
 ; OBJ64:      ]
 ; OBJ64:      Relocations [
-; OBJ64-NEXT:   0x64 IMAGE_REL_AMD64_SECREL x
-; OBJ64-NEXT:   0x68 IMAGE_REL_AMD64_SECTION x
-; OBJ64-NEXT:   0x9C IMAGE_REL_AMD64_SECREL x
-; OBJ64-NEXT:   0xA0 IMAGE_REL_AMD64_SECTION x
-; OBJ64-NEXT:   0x100 IMAGE_REL_AMD64_SECREL y
-; OBJ64-NEXT:   0x104 IMAGE_REL_AMD64_SECTION y
-; OBJ64-NEXT:   0x138 IMAGE_REL_AMD64_SECREL y
-; OBJ64-NEXT:   0x13C IMAGE_REL_AMD64_SECTION y
-; OBJ64-NEXT:   0x19C IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x1A0 IMAGE_REL_AMD64_SECTION f
-; OBJ64-NEXT:   0x1D4 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x1D8 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x70 IMAGE_REL_AMD64_SECREL x
+; OBJ64-NEXT:   0x74 IMAGE_REL_AMD64_SECTION x
+; OBJ64-NEXT:   0xA8 IMAGE_REL_AMD64_SECREL x
+; OBJ64-NEXT:   0xAC IMAGE_REL_AMD64_SECTION x
+; OBJ64-NEXT:   0x10C IMAGE_REL_AMD64_SECREL y
+; OBJ64-NEXT:   0x110 IMAGE_REL_AMD64_SECTION y
+; OBJ64-NEXT:   0x144 IMAGE_REL_AMD64_SECREL y
+; OBJ64-NEXT:   0x148 IMAGE_REL_AMD64_SECTION y
+; OBJ64-NEXT:   0x1A8 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x1AC IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x1E0 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x1E4 IMAGE_REL_AMD64_SECTION f
 ; OBJ64-NEXT: ]
 ; OBJ64:      Subsection [
 ; OBJ64-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ64:        {{.*}}Proc{{.*}}Sym {
 ; OBJ64:          Kind: S_LPROC32_ID (0x1146)
 ; OBJ64:          CodeSize: 0xE
 ; OBJ64:          DisplayName: x
 ; OBJ64:          LinkageName: x

llvm/test/DebugInfo/COFF/pr28747.ll

 ; RUN: llc < %s | FileCheck %s
 ; CHECK:             .section .debug$S,"dr"{{$}}
 ; CHECK-NEXT:        .p2align 2
 ; CHECK-NEXT:        .long 4
 ; CHECK-NEXT:        .long  241
 ; CHECK-NEXT:        .long  [[SUBSEC_END:.*]]-[[SUBSEC_START:.*]] # Subsection size
 ; CHECK-NEXT:        [[SUBSEC_START]]:
-; CHECK-NEXT:        .short [[C1_END:.*]]-[[C1_START:.*]] # Record length
-; CHECK:             [[C1_END]]:
+; CHECK-NEXT:        .short [[OBJNAME_END:.*]]-[[OBJNAME_START:.*]] # Record length
+; CHECK:             [[OBJNAME_END]]:
+; CHECK-NEXT:        .short [[COMPILE3_END:.*]]-[[COMPILE3_START:.*]] # Record length
+; CHECK:             [[COMPILE3_END]]:
 ; CHECK-NEXT:        [[SUBSEC_END]]:
 ; CHECK-NEXT:        .p2align 2
 ; CHECK-NEXT:        .cv_filechecksums
 ; CHECK-NEXT:        .cv_stringtable
 
 target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
 target triple = "i686-pc-windows-msvc18.0.0"
 

llvm/test/DebugInfo/COFF/simple.ll

 ; X86-LABEL: .section        .debug$S,"dr"
 ; X86-NEXT: .p2align 2
 ; X86-NEXT: .long   4
 ; Symbol subsection
 ; X86-NEXT: .long   241
 ; X86-NEXT: .long [[COMPILE_END:.*]]-[[COMPILE_START:.*]] #
 ; Compiler information record
 ; X86-NEXT: [[COMPILE_START]]:
-; X86-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X86:      [[C1_END]]:
+; X86-NEXT: .short [[OBJNAME_END:.*]]-[[OBJNAME_START:.*]] #
+; X86:      [[OBJNAME_END]]:
+; X86-NEXT: .short [[COMPILE3_END:.*]]-[[COMPILE3_START:.*]] #
+; X86:      [[COMPILE3_END]]:
 ; X86-NEXT: [[COMPILE_END]]:
 ; X86-NEXT: .p2align  2
 ; X86-NEXT: .cv_fpo_data _f
 ; X86-NEXT: .long 241  # Symbol subsection for f
 ; X86-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] # Subsection size
 ; X86-NEXT: [[F1_START]]:
 ; X86-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X86-NEXT: [[PROC_SEGMENT_START]]:

 ; String table
 ; X86-NEXT: .cv_stringtable
 
 ; OBJ32:    Section {
 ; OBJ32:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ32:      Characteristics [ (0x42300040)
 ; OBJ32:      ]
 ; OBJ32:      Relocations [
-; OBJ32-NEXT:   0x44 IMAGE_REL_I386_DIR32NB _f
-; OBJ32-NEXT:   0x90 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0x94 IMAGE_REL_I386_SECTION _f
-; OBJ32-NEXT:   0xC8 IMAGE_REL_I386_SECREL _f
-; OBJ32-NEXT:   0xCC IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0x50 IMAGE_REL_I386_DIR32NB _f
+; OBJ32-NEXT:   0x9C IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0xA0 IMAGE_REL_I386_SECTION _f
+; OBJ32-NEXT:   0xD4 IMAGE_REL_I386_SECREL _f
+; OBJ32-NEXT:   0xD8 IMAGE_REL_I386_SECTION _f
 ; OBJ32-NEXT: ]
 ; OBJ32:      Subsection [
 ; OBJ32-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ32:  Compile3Sym
 ; OBJ32:      ]
 ; OBJ32:      Subsection [
 ; OBJ32-NEXT:   SubSectionType: FrameData (0xF5)
 ; OBJ32:      ]

 ; X64-LABEL: .section        .debug$S,"dr"
 ; X64-NEXT: .p2align 2
 ; X64-NEXT: .long   4
 ; Symbol subsection
 ; X64-NEXT: .long   241
 ; X64-NEXT: .long [[COMPILE_END:.*]]-[[COMPILE_START:.*]] #
 ; Compiler information record
 ; X64-NEXT: [[COMPILE_START]]:
-; X64-NEXT: .short [[C1_END:.*]]-[[C1_START:.*]] #
-; X64:      [[C1_END]]:
+; X64-NEXT: .short [[OBJNAME_END:.*]]-[[OBJNAME_START:.*]] #
+; X64:      [[OBJNAME_END]]:
+; X64-NEXT: .short [[COMPILE3_END:.*]]-[[COMPILE3_START:.*]] #
+; X64:      [[COMPILE3_END]]:
 ; X64-NEXT: [[COMPILE_END]]:
 ; X64-NEXT: .p2align  2
 ; X64-NEXT: .long 241  # Symbol subsection for f
 ; X64-NEXT: .long [[F1_END:.*]]-[[F1_START:.*]] # Subsection size
 ; X64-NEXT: [[F1_START]]:
 ; X64-NEXT: .short [[PROC_SEGMENT_END:.*]]-[[PROC_SEGMENT_START:.*]] #
 ; X64-NEXT: [[PROC_SEGMENT_START]]:
 ; X64-NEXT: .short  4423

 ; String table
 ; X64-NEXT: .cv_stringtable
 
 ; OBJ64:    Section {
 ; OBJ64:      Name: .debug$S (2E 64 65 62 75 67 24 53)
 ; OBJ64:      Characteristics [ (0x42300040)
 ; OBJ64:      ]
 ; OBJ64:      Relocations [
-; OBJ64-NEXT:   0x64 IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0x68 IMAGE_REL_AMD64_SECTION f
-; OBJ64-NEXT:   0x9C IMAGE_REL_AMD64_SECREL f
-; OBJ64-NEXT:   0xA0 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0x70 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0x74 IMAGE_REL_AMD64_SECTION f
+; OBJ64-NEXT:   0xA8 IMAGE_REL_AMD64_SECREL f
+; OBJ64-NEXT:   0xAC IMAGE_REL_AMD64_SECTION f
 ; OBJ64-NEXT: ]
 ; OBJ64:      Subsection [
 ; OBJ64-NEXT:   SubSectionType: Symbols (0xF1)
 ; OBJ64:        {{.*}}Proc{{.*}}Sym {
 ; OBJ64:          CodeSize: 0xE
 ; OBJ64:          DisplayName: f
 ; OBJ64:          LinkageName: f
 ; OBJ64:        }

llvm/test/DebugInfo/COFF/vframe-fpo.ll

 ; ASM-NEXT:    calll   "?g@@YAXAAH00@Z"
 
 ; CODEVIEW:      CodeViewDebugInfo [
 ; CODEVIEW-NEXT:   Section: .debug$S (4)
 ; CODEVIEW-NEXT:   Magic: 0x4
 ; CODEVIEW-NEXT:   Subsection [
 ; CODEVIEW-NEXT:     SubSectionType: Symbols (0xF1)
 ; CODEVIEW-NEXT:     SubSectionSize:
-; CODEVIEW-NEXT:     Compile3Sym {
+; CODEVIEW-NEXT:     ObjNameSym {
+; CODEVIEW-NEXT:       Kind: S_OBJNAME (0x1101)
+; CODEVIEW:          Compile3Sym {
 ; CODEVIEW-NEXT:       Kind: S_COMPILE3 (0x113C)
 ; CODEVIEW:          }
 ; CODEVIEW:        ]
 ; CODEVIEW:        Subsection [
 ; CODEVIEW-NEXT:     SubSectionType: FrameData (0xF5)
 ; CODEVIEW-NEXT:     SubSectionSize:
 ; CODEVIEW-NEXT:     LinkageName: _main
 ; CODEVIEW:          FrameData {

llvm/test/MC/AArch64/coff-debug.ll

 ; RUN: llc -mtriple=aarch64-windows -filetype=obj -o - %s | \
-; RUN: llvm-readobj --codeview - | FileCheck %s
+; RUN: llvm-readobj --codeview - | FileCheck %s --check-prefixes=CHECK,CHECK-STDOUT
+; RUN: llc -mtriple=aarch64-windows -filetype=obj -o %t.o %s
+; RUN: llvm-readobj --codeview %t.o | FileCheck %s --check-prefixes=CHECK,CHECK-FILE
 
 ; ModuleID = 'a.c'
 source_filename = "a.c"
 target datalayout = "e-m:w-p:64:64-i32:32-i64:64-i128:128-n32:64-S128"
 target triple = "aarch64--windows-msvc18.0.0"
 
 ; Function Attrs: noinline nounwind optnone
 define i32 @main() #0 !dbg !7 {

 ; CHECK:     Name: main
 ; CHECK:   }
 ; CHECK: ]
 ; CHECK: CodeViewDebugInfo [
 ; CHECK:   Section: .debug$S (4)
 ; CHECK:   Magic: 0x4
 ; CHECK:   Subsection [
 ; CHECK:     SubSectionType: Symbols (0xF1)
+; CHECK:     ObjNameSym {
+; CHECK:       Kind: S_OBJNAME (0x1101)
+; CHECK:       Signature: 0x0
+; CHECK-STDOUT: ObjectName: {{$}}
+; CHECK-FILE:   ObjectName: {{.*}}.o
+; CHECK:     }
 ; CHECK:     Compile3Sym {
 ; CHECK:       Kind: S_COMPILE3 (0x113C)
 ; CHECK:       Language: C (0x0)
 ; CHECK:       Flags [ (0x0)
 ; CHECK:       ]
 ; CHECK:     }
 ; CHECK:   ]
 ; CHECK:   Subsection [

llvm/test/MC/ARM/coff-debugging-secrel.ll

 ; CHECK-ITANIUM:   }
 ; CHECK-ITANIUM:   Section {{.*}}.debug_pubnames {
 ; CHECK-ITANIUM:     0x6 IMAGE_REL_ARM_SECREL .debug_info
 ; CHECK-ITANIUM:   }
 ; CHECK-ITANIUM: ]
 
 ; CHECK-MSVC: Relocations [
 ; CHECK-MSVC:   Section {{.*}} .debug$S {
-; CHECK-MSVC:     0x64 IMAGE_REL_ARM_SECREL function
-; CHECK-MSVC:     0x68 IMAGE_REL_ARM_SECTION function
-; CHECK-MSVC:     0xA0 IMAGE_REL_ARM_SECREL function
-; CHECK-MSVC:     0xA4 IMAGE_REL_ARM_SECTION function
+; CHECK-MSVC:     0x70 IMAGE_REL_ARM_SECREL function
+; CHECK-MSVC:     0x74 IMAGE_REL_ARM_SECTION function
+; CHECK-MSVC:     0xAC IMAGE_REL_ARM_SECREL function
+; CHECK-MSVC:     0xB0 IMAGE_REL_ARM_SECTION function
 ; CHECK-MSVC:   }
 ; CHECK-MSVC: ]
 

llvm/test/MC/COFF/cv-compiler-info.ll

-; RUN: llc -mtriple i686-pc-windows-msvc < %s | FileCheck %s
+; RUN: llc -mtriple i686-pc-windows-msvc < %s | FileCheck %s --check-prefixes=CHECK,STDOUT
+; RUN: llc -mtriple i686-pc-windows-msvc < %s -o %t
+; RUN: FileCheck %s --input-file=%t --check-prefixes=CHECK,FILE
 ; ModuleID = 'D:\src\scopes\foo.cpp'
 source_filename = "D:\5Csrc\5Cscopes\5Cfoo.cpp"
 target datalayout = "e-m:x-p:32:32-i64:64-f80:32-n8:16:32-a:0:32-S32"
 target triple = "i686-pc-windows-msvc19.0.23918"
 
 ; Function Attrs: nounwind sspstrong
 define i32 @"\01?foo@@YAHXZ"() #0 !dbg !10 {
 entry:
   ret i32 42, !dbg !14
 }
 
 attributes #0 = { nounwind sspstrong "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "frame-pointer"="all" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "target-cpu"="pentium4" "target-features"="+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
 
 !llvm.dbg.cu = !{!0}
 !llvm.module.flags = !{!7, !8}
 !llvm.ident = !{!9}
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 4.0.0 ", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
 ; One .debug$S section should contain an S_COMPILE3 record that identifies the
 ; source language and the version of the compiler based on the DICompileUnit.
 ; CHECK:  .section  .debug$S,"dr"
+; CHECK:        .short  4353                    # Record kind: S_OBJNAME
+; CHECK-NEXT:   .long   0                       # Signature
+; STDOUT-NEXT:  .byte   0                       # Object name
+; FILE-NEXT:    .asciz  "{{.*}}{{\\\\|/}}cv-compiler-info.ll.tmp" # Object name
 ; CHECK:    .short  4412                  # Record kind: S_COMPILE3
-; CHECK:    .long 1                       # Flags and language
-; CHECK:    .short  7                     # CPUType
-; CHECK:    .short  4                     # Frontend version
-; CHECK:    .short  0
-; CHECK:    .short  0
-; CHECK:    .short  0
-; CHECK:    .short  [[BACKEND_VERSION:[0-9]+]]  # Backend version
-; CHECK:    .short  0
-; CHECK:    .short  0
-; CHECK:    .short  0
-; CHECK:    .asciz  "clang version 4.0.0 "  # Null-terminated compiler version string
-; CHECK-NOT: .short 4412                  # Record kind: S_COMPILE3
+; CHECK-NEXT:   .long 1                       # Flags and language
+; CHECK-NEXT:   .short  7                     # CPUType
+; CHECK-NEXT:   .short  4                     # Frontend version
+; CHECK-NEXT:   .short  0
+; CHECK-NEXT:   .short  0
+; CHECK-NEXT:   .short  0
+; CHECK-NEXT:   .short  [[BACKEND_VERSION:[0-9]+]]  # Backend version
+; CHECK-NEXT:   .short  0
+; CHECK-NEXT:   .short  0
+; CHECK-NEXT:   .short  0
+; CHECK-NEXT:   .asciz  "clang version 4.0.0 "  # Null-terminated compiler version string
+; CHECK-NOT:    .short  4412                  # Record kind: S_COMPILE3
 !1 = !DIFile(filename: "D:\5Csrc\5Cscopes\5Cfoo.cpp", directory: "D:\5Csrc\5Cscopes\5Cclang")
 !2 = !{}
 !7 = !{i32 2, !"CodeView", i32 1}
 !8 = !{i32 2, !"Debug Info Version", i32 3}
 !9 = !{!"clang version 4.0.0 "}
 !10 = distinct !DISubprogram(name: "foo", linkageName: "\01?foo@@YAHXZ", scope: !1, file: !1, line: 1, type: !11, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, retainedNodes: !2)
 !11 = !DISubroutineType(types: !12)
 !12 = !{!13}
 !13 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
 !14 = !DILocation(line: 2, scope: !10)

llvm/tools/llc/llc.cpp

static int compileModule(char **argv, LLVMContext &Context) {
   if (codegen::getFloatABIForCalls() != FloatABI::Default)
     Options.FloatABIType = codegen::getFloatABIForCalls();
 
   // Figure out where we are going to send the output.
   std::unique_ptr<ToolOutputFile> Out =
       GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
   if (!Out) return 1;
 
+  // Ensure the filename is passed down to CodeViewDebug.
+  Target->Options.ObjectFilenameForDebug = Out->outputFilename();
+
   std::unique_ptr<ToolOutputFile> DwoOut;
   if (!SplitDwarfOutputFile.empty()) {
     std::error_code EC;
     DwoOut = std::make_unique<ToolOutputFile>(SplitDwarfOutputFile, EC,
                                                sys::fs::OF_None);
     if (EC)
       reportError(EC.message(), SplitDwarfOutputFile);
   }

llvm/tools/llvm-lto2/llvm-lto2.cpp

if (HasErrors)
     return 1;
 
   auto AddStream = [&](size_t Task) -> std::unique_ptr<CachedFileStream> {
     std::string Path = OutputFilename + "." + utostr(Task);
 
     std::error_code EC;
     auto S = std::make_unique<raw_fd_ostream>(Path, EC, sys::fs::OF_None);
     check(EC, Path);
-    return std::make_unique<CachedFileStream>(std::move(S));
+    return std::make_unique<CachedFileStream>(std::move(S), Path);
   };
 
   auto AddBuffer = [&](size_t Task, std::unique_ptr<MemoryBuffer> MB) {
     *AddStream(Task)->OS << MB->getBuffer();
   };
 
   FileCache Cache;
   if (!CacheDir.empty())